SYSTEM FOR RIVET FASTENING

SYSTEME DE FIXATION DE RIVETS

English Abstract

A system and method for rivet setting comprising an anvil having an anvil face, a plunger having a sensor coupled to a control system that measures the distance between the anvil face and the work surface during the rivet setting process and stops the rivet driver when the driven rivet head achieves a desired head height above the work surface. In preferred embodiments, the control system also communicates the stage of the rivet driving cycle to the operators to expedite the rivet driving process.

French Abstract

La présente invention concerne un système et un procédé permettant d'installer des rivets, comprenant une enclume possédant une face d'enclume, un piston possédant un capteur accouplé à un système de commande qui mesure la distance entre la face d'enclume et la surface de travail pendant le procédé d'installation de rivets et qui arrête le dispositif d'entraînement de rivets lorsque la tête de rivet entraînée atteint une hauteur de tête souhaitée au-dessus de la surface de travail. Selon des modes de réalisation préférés, le système de commande communique également le stade du cycle d'entraînement de rivets aux opérateurs pour accélérer le procédé d'entraînement de rivets.

Claims

EMBODIMENTS IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS
CLAIMED ARE DEFINED AS FOLLOWS:

1. A system for
fastening a rivet in a workpiece with a rivet driver, the workpiece having
a work surface, the rivet having a manufactured head, a shank, and a shank
end, the
shank and shank end nominally projecting from the work surface, the system
comprising:
an anvil having an anvil face;
a plunger slidably engaged with said anvil, said plunger having a plunger
distal
end, the plunger distal end nominally extending beyond said anvil face;
a load source that is operative to nominally urge said plunger distal end
forward
relative to said anvil face to maintain contact with the work surface;
a sensor that is operative to sense a distance between the plunger distal end
and
the anvil face and produce a first input signal related to said distance; and
a control subsystem comprising a controller, said control subsystem operative
to:
enable and disable the rivet driver; and

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receive the first input signal from the said sensor and send an output signal
to the controller, and disable the rivet driver when said distance is
substantially equal to a desired rivet head height.
2. The system of claim 1, further comprising:
a first sensor configuration consisting of said sensor that is operative to
produce
said first input signal when said anvil face first contacts the shank end; or
a second sensor configuration consisting of a second sensor that is first
operative
to produce a second input signal when said anvil face first contacts the shank
end
and a further sensor that is second operative to produce a further input
signal
when said anvil face first contacts the shank end; or
a third sensor configuration consisting of a third sensor that is operative to

produce a third input signal when said anvil face contacts the shank end; and
wherein said first, second or third sensor configurations are each operative
to
sense said distance when said anvil face first contacts said shank end, and
produces a specific input signal related to said distance;
wherein said specific input signal from any sensor configuration of said
first,
second or third sensor configurations is representative of a shank length
nominally projecting from said work surface upon said first contact; and
wherein said control subsystem:
receives said specific input signal from said any sensor configuration;

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stores said distance;
determines said desired rivet head height; and
stores said desired rivet head height.
3. The system of claim 1, further comprising:
a fourth sensor having a plurality of spindles feet at said distal end of said

plunger, the fourth sensor operative to produce a fourth input signal when the

spindles feet are substantially in contact with said work surface; and
wherein the control subsystem is operative to:
at least one of determine if the anvil face is substantially parallel to said
work surface and determine if said spindles feet are substantially in contact
with said work surface; and
disable the rivet driver when said anvil face is not substantially parallel to

said work surface or when said spindles feet are not substantially in contact
with said work surface.
4. The system of claim 1, further comprising:
a set tool that is coupled to the rivet driver at a first end and is operative
to impact
the manufactured head at a second end;

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a fifth sensor that is operative to produce a fifth input signal when driving
the
rivet and said second end of said set tool is substantially in communication
with
said manufactured head; and
wherein said control subsystem is operative to:
evaluate said fifth input signal from said fifth sensor to determine when
said second end of the set tool is not substantially in communication with
the manufactured head; and
disable the rivet driver when said second end of said set tool is not
substantially in communication with the manufactured head.
5. The system of claim 4, further comprising:
a first indicator that is operative to indicate when said second end of said
set tool
makes contact with said manufactured head; and
wherein said control system receives the fifth input signal from said fifth
sensor
and is operative to toggle said first indicator that indicates that said
second end of
said set tool is in contact with said manufactured head and representative
that a
rivet gun operator is in "ready" condition.
6. The system of claim 2, further comprising:

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a second indicator that is operative to indicate when said anvil face makes
contact with said shank end; and
wherein the control subsystem receives the third input signal from the third
sensor and is operative to toggle said second indicator that indicates that
said
anvil face is in contact with said shank end and representative that a bucking
bar
operator is in "ready" condition.
7. The system of claim 3, further comprising:
a third indicator that is operative to indicate when said spindles feet are in
contact
with said work surface; and
wherein said control subsystem receives said fourth input signal from said
fourth
sensor and is operative to:
determine, when driving the rivet, if said spindles feet are substantially in
contact with said work surface; and
toggle said third indicator that indicates said spindles feet are not
substantially in contact with said work surface.
8. The system of claim 5 wherein said control subsystem receives said first
indicator or an
input signal from a second sensor; and
wherein said control subsystem is operative to:

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determine if said second end of said set tool is substantially in
communication with said manufactured head;
determine a damage event condition; and
operate said controller to disable said rivet driver when said damage event
condition is determined.
9. The system of claim 6 wherein said control subsystem receives said
second indicator or
said second input signal from said second sensor; and
wherein said control subsystem is operative to:
determine if said anvil is substantially in communication with said shank
end;
determine a damage event condition; and
operate said controller to disable said rivet driver when said damage event
condition is determined.
10. The system of claim 2 wherein the control subsystem:
receives the said first input signal from said sensor, or receives said second
input
signal from said second sensor and then receives said first input signal from
said
sensor, or receives said second input signal from said second sensor and then
receives said further input signal from said further sensor, or receives said
third
input signal from said third sensor; and

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is operative to determine and store the desired rivet head height.
11. The system of any one of claims 1, 2 or 10 wherein said control
subsystem:
determines the desired rivet head height;
is operative to analyze the first input signal from said sensor to assess
plastic
deformation of a rivet shank; and
is operative to disable the rivet driver when said distance is substantially
equal to
said desired rivet head height.
12. The system of any one of claims 1 to 11, further comprising:
a user input device that is operative to receive input from a user; and
wherein said control subsystem is operative to receive said input from said
user
and the first input signal from said sensor when said plunger distal end is a
known distance from said anvil face, to calibrate the distance between said
plunger distal end and said anvil face.
13. The system of any one of claims 1 to 12:
wherein the sensor has a switching threshold and is operative to produce a
digital
signal; and

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whereby a physical feature on the plunger actuates the switching threshold of
said sensor when the plunger is axially displaced a distance representative of
the
desired rivet head height.
14. The system of any one of claims 1 to 13, further comprising:
a sixth sensor that is operative to sense an impact magnitude from a rivet
diver
blow, and produce a sixth input signal when the rivet driver produces an
impact
on the rivet; and
wherein said control subsystem receives said sixth input signal and is
operative to
determine and store at least one of:
a tally of said impacts required to set the rivet to said desired rivet head
height; and
an impact frequency of the rivet driver.
15. The system of any one of claims 1 to 14 wherein the control subsystem
comprises at
least one control subsystem, the system further comprising:
a data base operating on a central computer, said central computer being
operative to receive a plurality of data sets from the at least one control
subsystem and store said data sets in said data base; and
wherein the data sets comprise data consisting of at least one of:



a protruding rivet shank length;
the desired rivet head height;
a rivet set head height; and
a count of impacts from the rivet driver, required to form said rivet set head

height.
16. The system of any one of claims 1 to 15, further comprising:
said controller, said controller operative to enable and disable said rivet
driver,
and said controller comprising an input coupled to a power source and an
output
coupled to the rivet driver; and
wherein the control subsystem:
disables the rivet driver by actuating said controller to decouple the power
source from the rivet driver, or
enables said rivet driver by actuating the controller to couple the power
source to the rivet driver.
17. The system of claims 1 to 14 wherein the control subsystem comprises a
plurality of
control subsystems, the system further comprising:
a memory;

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an addressable communication capability between at least two of the plurality
of
control subsystems;
a central computer having central memory, said central computer in
communication with or comprised of at least one of the plurality of control
subsystem;
wherein said plurality of control subsystems are operable to transfer a data
set of
riveting information to said central memory; and
wherein said central memory stores said data set.
18. The system of
any one of claims 1 to 14, wherein the control subsystem comprises at
least two control subsystems, the system further comprising first and second
radios
coupled between the at least two control subsystems and operative to send and
receive
data between said at least two control subsystems.

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Description

SYSTEM FOR RIVET FASTENING
BACKGROUND
This disclosure relates to a system and method for fastening rivets and/or
using process
indicators to communicate to operators the stage of each rivet during a rivet
setting cycle. In
particular, the disclosure relates to a system and method that relies on
sensors that are used as
part of a feedback control system to achieve rivet setting tolerances by
measuring in real-time or
near-real-time the rivet's driven head (sometimes called the upset head or
shop head) height
while the control system also controls rivet gun operation and communicates
the rivet driving
cycle stage to the rivet setting operator(s).
Riveting produces the strongest practical means of fastening airplane skins
and
substructure together. Although the cost of installing one rivet is small,
installing the great
number of rivets used in airplane manufacture represents a large percentage of
the total cost of
any airplane.
1
Date recu/Date Received 2020-04-20

CA 02892774 2015-05-21
WO 2014/081404
PCT/US2012/000561
It should be first noted that the term "tolerance" is used broadly throughout
this disclosure.
Conventionally, the term tolerance signifies a plus or minus range of
acceptance on a bell-shaped-curve distribution
of samples with preferably the peak of the bell-shaped curve representing the
optimum and the distribution of
samples being bounded by a narrow band having upper and lower specification
limits. The curve is used with a
measure of standard deviation to quantitatively characterize defects by a
measure of standard deviation or sigma
value. In this disclosure, the term tolerance also sometimes refers to a
specific value representing the optimum peak
of the bell-curve (or very near peak, i.e., extremely tight tolerance). For
example, "It is often difficult to consistently
set rivets to meet tolerances but it is extremely difficult to consistently
set rivets to an optimal tolerance." In other
words, a very tight tolerance being met consistently by a large data set
having that is both accurate and precise also
has a high sigma value.
Although this invention may be applied to special types of rivets, for
purposes of clarity, this disclosure
uses as an example conventional solid-shank rivets that comprise a
manufactured head, a shank, a shank end, and a
driven head. The driven head is formed by upsetting the rivet shank with a
rivet gun or rivet driver while backing
the shank with a bucking bar. The shank actually expands slightly while being
driven so the rivet fits tightly in the
drilled hole and the shank end deforms to produce a driven head. Fastened
material is then held between the
manufactured head and the driven head.
Where there is easy access to both sides of the work, the rivet-gun operator
can sometimes simultaneously
drive the rivet and back the rivet with a bucking bar; however, in most cases
both a rivet-gun operator and a
bucking-bar operator or bucker must work together to drive solid-shank rivets.
The conventional procedure for
driving rivets is as follows: (I) the rivet gun operator adjusts the air
regulator which controls the air pressure and/or
air flow to increase or decrease hitting force of the pneumatic rivet gun;
next (2) the rivet gun operator inserts the
rivet into the drilled hole, places the rivet set tool anvil face against the
rivet and waits for the bucker; next (3) the
bucker holds the bucking bar anvil face on the opposite end of the rivet; next
(4) the rivet gun operator should "feel"
the pressure being applied by the bucker through the rivet; and finally (5)
the rivet-gun operator will start the rivet
gun by pulling the trigger to release a short burst of rivet-gun blows and
then stop the rivet gun when the rivet has
been driven or set to be within a desired range of manufacturing
specifications or tolerances. Forward-set rivets are
formed when the set tool hammers on the manufactured head and the bucking bar
backs the shank end of the rivet.
Backset rivets are formed when the set tool hammers on the shank end of the
rivet and the bucking bar backs the
manufactured head of the rivet. It is to be understood that teachings of this
disclosure apply to both forward-set and
backset rivet driving methods and one skilled in the art could apply the
teachings of one method to achieve another
method.
Throughout the rivet setting process, both operators must hold their tools
perpendicular or orthogonal to the
work so the rivet is driven axially. The entire rivet setting process requires
both skill and experience since the rivet-
gun operator must determine rivet gun burst-length or blows needed according
to variables such as manual forces
2

applied by either bucker or gun operator, the rivet size being driven, the
rivet gun design and air-
flow or pressure settings and the mass of the rivet gun and bucking bars.
These variables must be
judged by the rivet-gun operator to time the length of the rivet driving stage
needed to achieve
desired rivet set tolerances.
Further, to communicate with each other, the rivet-gun operator and bucker
conventionally
use a tapping code to enable the bucker to communicate with the rivet-gun
operator: one-tap on the
rivet by the bucker means start or resume driving the rivet (resuming is often
necessary when the
rivet has been under-driven and has not reached tolerance); two-taps on the
rivet by the bucker
means the finished or set rivet was within satisfactory tolerance; three-taps
on the rivet by the
bucker means the rivet was improperly set and must be removed (this typically
occurs when the
rivet has been over-driven and can not be modified to achieve tolerance).
Where verbal
communication is possible, the rivet-gun operator typically announces "ready"
when he is ready to
begin riveting and waits for the bucker to likewise announce "ready" when he
is ready to begin
bucking and follows with a "good", "drive more" or "not good" verbal report of
the completed set
rivet.
To achieve design strength, the driven head of a rivet must fall within an
acceptable
tolerance range; to inspect rivets, the bucker sometimes uses a gauge to
measure the driven head-
height or driven head-width after the rivet has been set. Often, however, to
save time, the bucker
only visually inspects the driven head to determine if it meets required
tolerances. If the rivet has
been under-driven leaving the head height too high, additional driving is
needed (although due to
work hardening of the rivet material, rivet holding strength for rivets driven
in repeated driving
stages is often reduced). Over-driven rivets require removal, which is a time
consuming process
that can often damage the work and sometimes requires using an oversized
replacement rivet
having a different setting tolerance. Over-driven rivets often blemish or bend
the work, sometimes
causing costly rework or irreparable damage.
The background art is characterized by U.S. Patent Nos. 1,803,965; 2,354,914;
3,478,567;
3,559,269; 3,574,918; 3,933,025; 4,218,911; 4,566,182; 5,398,537; 5,953,952;
6,011,482;
6,088,897; 6,357,101; 6,363,768; 6,823,709; and 7,331,205.
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CA 2892774 2018-01-08

Although the conventional method of driving rivets described above has been
effective for
many years, some background art methods have unsuccessfully attempted to
improve the process.
What is needed is a rivet fastener system that overcomes the disadvantages of
the background art;
such a rivet fastening system is disclosed herein.
BRIEF SUMMARY
The present disclosure describes means and methods for fastening rivets and/or
using
process indicators to communicate to operators the driving stage of each rivet
during a rivet setting
cycle.
As used herein, the following terms and variations thereof have the meanings
given below,
unless a different meaning is clearly intended by the context in which such
term is used:
"A," "an" and "the" and similar referents used herein are to be construed to
cover both the
singular and the plural unless their usage in context indicates otherwise.
"About" and "approximately" mean within plus or minus ten percent of a recited
parameter
or measurement, and preferably within plus or minus five percent of such
parameter or
measurement; if a parameter or measure is not referenced, these terms mean
that a reasonable
allowance in parameter or measurement is permitted as one skilled in the art
might determine.
"Comprise" and variations of the term, such as "comprising" and "comprises,"
as well as
"having" and "including" are not intended to exclude other additives,
components, integers, or
steps.
"Debounces" means any kind of hardware device or software that identifies only
one
digital signature from a plurality of digital signatures within the space of a
determined time
(usually milliseconds).
"Exemplary," "illustrative," and "preferred" mean "another."
"Substantially" means "equivalent" or "approximately equivalent" or "about
equal to",
given equipment and conditions involved.
"Desired rivet head height" means "rivet head height within the specification"
(between
upper and lower specification limits) but can also have a tighter tolerance
than the specification.
"Switching threshold" means a measured relative position, point, or location
where a
switching operation occurs; where switching is a reversible transition from
high-resistivity state to
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CA 2892774 2018-01-08

a low-resistivity state or the equivalent as determined by software and the
relative position is
preferably both accurate and precise.
"Loop circuit" means an electrically conductive path; when coupled with
microprocessor
software to detect a "make" or a "break" in the circuit, a sensor is produced.
"Rivet driver" means any equipment used to impart work energy to deform a
rivet shank,
e.g., a rivet driver includes a hand-held manually operated rivet gun or a
robotically operated
hammering machine. The term "rivet gun" may be replaced by "rivet driver."
"Anvil face" means a rivet impacting surface of an anvil on a bucking bar or a
set tool.
"First contact" means when an anvil face first makes contact with a rivet
manufactured
head or a shank end, preferably at the beginning of a rivet driving stage and
just before the rivet
driver is enabled.
"Control subsystem" means any subset of a control system optionally including
a
"controller" and may be comprised of at least one of: a microprocessor, a
microcontroller, a
computer or digital logic device;
"Controller" may be any driver device comprised of a relay a field effect
transistor a
transistor or a microprocessor; a driver device may be any intermediate device
or equipment used
to operate or actuate another device or equipment such as a valve. In some
cases the term
"controller" can also mean microprocessor, microcontroller, computer or other
digital logic device.
"Visual indicator" means a "visually observable communication signal" and may
be
synonymous with terms "indicator", "visual signal", "light", or "Light
Emitting Diode."
"Power regulator" means anything to provide a controlled or specific "power
level" or
"energy level- or "force level;" an example for pneumatic power supply a power
regulator is an air
regulator.
"Resilient member" means a "load source" and may be understood as a force
applying
system or component; for example a spring.
In this disclosure, a plurality of sensors are described. Various sensors
perform various
tasks and some sensors may perform a plurality of tasks. To better illustrate
the disclosure, these
sensors are summarized here and presented later in more detail when discussing
illustrative
embodiments of the invention.
= First sensor: A first sensor preferably is used to sense when a distance
between an
anvil face and a work surface represents a driven rivet head height that
substantially
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CA 2892774 2018-01-08

matches a desired rivet head height. First sensors may be either analogue or
digital.
This sensor is used to determine when to cease riveting.
= Second sensor: A second sensor preferably is used to sense when an anvil
face comes
into contact with a rivet manufactured head or a rivet shank end and may serve
as an
impact sensor. Preferably, a loop sensor is used in second sensors but other
sensor
types such as a current sourcing sensor or a touch capacitance sensor may be
used.
Preferably, second sensors are digital. This sensor is used for a plurality of
determining
purposes including at least one of: a possible damage event condition, a rivet
driver
impact, or providing a signal to measure a protruding rivet shank length.
= Third sensor: A third sensor preferably is used to sense when a distance
between an
anvil face and a work surface represents a protruding shank length.
Preferably, a third
sensor works in conjunction with a second sensor where a signal from a second
sensor
is needed to indicate when an anvil face first comes into contact with a rivet
shank end.
A third sensor is preferably analogue and, therefore, may also be used as a
first sensor.
A purpose of a third sensor is to sense a rivet protruding shank length when
an anvil
face first comes into contact with a rivet shank end and normally requires a
second
sensor to determine when this contact occurs; however, it is possible for the
third
sensor to measure the described protruding shank length without using a second
sensor
(as described later).
= Fourth sensor: A fourth sensor preferably is used to sense tool alignment
by
determining spindles feet contact with work surface. Preferably, a loop sensor
is used
in fourth sensors but other sensor types such as a current sourcing sensor or
a touch
capacitance sensor may be used. Preferably, fourth sensors are digital.
Normally a
plurality of fourth sensors are on distal end of plunger and serve to detect
when the
spindles feet rest on a work surface.
In one embodiment there is described a way to measure the height of the formed
rivet head
during the rivet driving process and through a feedback control process
disable or stop the rivet gun
the moment the rivet head achieves the desired set tolerance. In this
embodiment, an automated
control process may allow both operators to focus on holding their tools
orthogonal to the work
surface and not be concerned about under-driving or over-driving the rivet.
Other embodiments
may provide a means for communicating the stage of the rivet driving process
to both rivet-gun and
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CA 2892774 2018-01-08

bucking operators by means of light, e.g., light-emitting diode (LED)
indicators, with at least one
LED located on or near the bucking bar and at least one LED located on or near
the rivet gun. By
detecting the switch states of one or more switches, the control system
operates the LED indicator
lights to sequentially signal the operators and thus guide them through each
sequential stage of the
rivet setting cycle.
Another embodiment may prevent inadvertent damage to the airframe by using a
control
system to disable the rivet gun when not needed and may enable the rivet gun
only when both the
rivet-gun operator and bucker have signaled (by LED lights via a
microprocessor detecting switch
.. states) that they are ready for the rivet driving stage of a rivet setting
cycle.
Another embodiment may use a unique micro-adjustable bucking bar that may be
adjusted
to toggle a switch state during the rivet driving stage when the height of a
rivet's driven head
achieves an optimal rivet set tolerance; this switching action may then
disable the rivet gun and
stop the riveting process. In this embodiment, preferably an electromechanical
switch and/or an
optical photo interrupter switch may be used to detect a rivet set threshold.
However, other means
of measuring the formed rivet head height during the rivet driving stage are
envisioned by the
applicant. For example, in an alternate embodiment, during the rivet's driving-
stage, continuous
analog measurement of the rivet head height above the work surface may be
achieved with a Linear
Variable Differential Transducer (LVDT) sensor. In this embodiment, a LVDT
sensor continuously
measures the formed rivet head height by likewise directly or indirectly
measuring the gap or
distance between the bucking anvil face and the work to determine the rivet-
head-height of the
driven rivet head. Embodiments comprising non-contact sensors are also
envisioned and may
include at least one inductive, capacitive and/or optical technologies.
Another embodiment may perform data logging in microprocessor memory of the
measured rivet driven head height after the rivet has been set for Quality
Assurance and Quality
Control verification purposes. Another embodiment may use a disclosed plunger
mechanism to
press pieces of joined work pieces together by applying compression spring
force to the work
surface during the rivet setting process. Additionally, the plunger mechanism
in this embodiment
may also form a shroud around the rivet head and thus may serve to prevent the
bucking tool from
sliding off the formed rivet head during the rivet driving stage. This may
reduce a damage event
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CA 2892774 2018-01-08

condition or reduce an opportunity of the rivet gun hammering on a rivet that
is not backed by a
bucking bar and thus causing damage to the airframe or substructure work.
Furthermore, the
plunger mechanism may also help the bucker maintain orthogonal alignment of
the bucking tool
relative to the work by holding the spindles feet of the plunger flush against
the work during the
.. rivet driving cycle.
Another embodiment may log at least one of the quality of set rivets, the
rivets setting
performance of operators, the time to complete specific riveting projects, and
the projected time to
complete specific riveting jobs.
While as previously stated embodiments may eliminate under-driving the rivet
and may
consequently prevent a plurality of hammering sessions; another embodiment may
maximize set
rivet material strength. During the rivet driving stage, the rivet shank may
undergo plastic
deformation; the shank-end may become the driven head and may forms into a
mushroom shape
.. and the shank also simultaneously expands. If the gun force is set too low,
then excessive rivet gun
blows or impacts are required to set 10 the rivet; this may cause the rivet
material to fatigue or
work harden resulting in reduced material strength of the rivet and therefore
reduced rivet holding
strength. Ideally to achieve the best rivet properties, rivets can be set with
a minimum number of
impacts but excessive rivet gun force may be difficult for operators to
control while simultaneously
.. maintaining tool alignment orthogonal to the work surface. In this
embodiment, therefore, the
control system may provide feedback for optimal air flow and/or air pressure
supplied to the gun
based on the number of impacts and/or the driving stage time to set a rivet.
In other words, the
feedback system may determine if the rivet gun impact force should be
increased or decreased
while also keeping the impacting force within acceptable operator-tool-control
limits. The rivet
setting time interval measurement begins when the rivet driving stage starts
and ends when the
driven head achieves optimum tolerance (when a measuring threshold has been
reached). The
number of impacts is may be counted by assessing the digital signature to
debounce the signals
from the bucking bar contact with the rivet, as detected by a momentary break
or switching in a
circuit by a computer or microprocessor. Alternately', an accelerometer or
other impact sensor
attached to the rivet gun, bucking bar or air supply line may be used to count
the number of rivet-
driving-stage impacts. Therefore, either an accelerometer or signal debouncer
may serve as an
impact sensor. Rivet setting time may be a measurement of the driving stage
time by a
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CA 2892774 2018-01-08

microprocessor. The control system may then indicate to the operator to
increase or decrease the
impact force via flow or pressure changes or alternately may automatically
make this adjustment
by controlling the air regulator settings or other settings for the rivet gun.
Any type of
communication such as LEDs, LED light bars or liquid crystal displays (LCDs)
may be used to
notify the rivet gun operator of recommended air-pressure regulator setting
changes.
In another embodiment, the operator may provide microprocessor inputs such as
the size of
the rivet being driven and the total joined sheathing material thickness into
the microprocessor's
memory via any type of input device such as a keypad. This may allow the
microprocessor to
determine the optimal number of impacts needed for the job in order to produce
the highest
strength rivets and may also determine the optimal tolerance threshold for the
formed rivet head
height (where analogue sensors are employed). Determining rivet size may also
be achieved by
measuring the protruding shank length after a rivet has been inserted into a
hole. Those skilled in
the art will appreciate that a control approach disclosed herein, coupled with
real-time or near-real-
time measurement of the upsetting rivet head, may also be used to set solid
shank rivets at a
specified location on a stress-strain curve to maximize rivet fastener
strength and durability.
Furthermore, accurate and precise measurement systems coupled to real-time
feedback control may
be incorporated into the disclosed embodiments, and may make it possible to
achieve "ideal" or
very low standard deviations (at, near or better than "six sigma") for any
desired rivet set objective.
Furthermore. even higher rivet set tolerance (higher standard deviation) is
desired to more precisely
control the set rivet product. Achieving extremely high tolerance levels may
involve feedback
and/or feed forward control strategies.
An illustrative embodiment, may comprise electronic circuits, a
microprocessor, software
code, sensors, switches, a specialized bucking bar or set tool equipment and
lights (such as LEDs)
to provide means of communication between the rivet gun operator and the
bucker and additionally
to provide feedback control of the rivet gun operation. In this embodiment,
several switches and
LEDs can be used to identify and communicate the stage of the riveting cycle
to the operators as
well as to enable the rivet gun; another switch may detect when a rivet has
been set to a specific
height or width and ends the riveting cycle by disabling the rivet gun. A
microprocessor operating
in accordance with software disclosed herein may read switch states and
controls the rivet setting
process by sequencing the rivet driving process (communicating the sequenced
rivet driving stage
to operators) by status LED lights indicators and may enable and disenable the
rivet gun. The
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circuit may include a multi-conductor cable that extends from a circuit board
located near the rivet
gun to the bucking bar system and may serve to service communication and
control; although, in
an alternate embodiment, this cable can be replaced with radio frequency (RF)
signals, infrared, or
other wireless means. In some embodiments, the bucking bar system may have a
microadjustable
gap-height setting that the operator sets to match the desired driven head
height of a rivet; when
this dimension is achieved during the rivet driving process, a switch can be
thrown which ends the
cycle by electromechanically disabling the rivet gun. The rivet gun may be
enabled and disabled by
electromechanical means including at least one of the following: an air
solenoid controlling air
power to the rivet gun or electromechanical control of gun operation.
Alternately, instead of having
a micro-adjustable gap-height setting capability, a plurality of tools may be
provided, with each
tool having a specific pre-calibrated rivet head height designed for setting a
corresponding specific
rivet size. Sensors may be digital or analogue.
In another embodiment, there is provided a method for setting a rivet in a
work piece, said
rivet having a rivet manufactured head and a shank having a shank end, said
method comprising:
sensing when a rivet set tool of a rivet gun has been placed on the rivet
manufactured head and
indicating to a bucking bar operator that a rivet gun operator is ready to
commence riveting;
sensing when a bucking bar has been placed on the shank end and indicating to
said rivet gun
operator that said bucking bar operator is ready to commence riveting; driving
the rivet by forcing
the shank against said bucking bar with said rivet set tool to form a driven
rivet head; sensing when
the height of said driven rivet head is substantially equal to a desired set
rivet head height and
indicating to both said bucking bar operator and said rivet gun operator that
said desired set rivet
head height has been achieved; and ceasing driving the rivet when said driven
rivet height is
substantially equal to said desired set rivet head height. The rivet gun may
be a pneumatic rivet
gun, the operation of which is controlled by a solenoid valve, said method
further comprising: first
actuating said solenoid valve when said driven rivet head height is
substantially equal to said
desired set rivet head height to operatively decouple said rivet gun from an
air supply source and
stop riveting; and second actuating said solenoid valve to operatively couple
said rivet gun to said
air supply source when said rivet gun operator and said bucking bar operator
are both ready to start
riveting. Said rivet gun may be a pneumatic rivet gun, the operation of which
is controlled by a
(e.g., normally open) solenoid valve, and said method further comprises:
closing said solenoid
valve when said driven rivet head height is substantially equal to said
desired set rivet head height.
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A person having ordinary skill in the art would understand that a normally
closed solenoid valve
may be used instead.
In another embodiment, there is provided a system for setting a rivet in a
work piece, said
rivet having a rivet manufactured head and a shank having a shank end, said
system comprising:
means for sensing when a rivet set tool has been placed on the rivet
manufactured head and
indicating to a bucking bar operator that a rivet gun operator is ready to
commence riveting; means
for sensing when a bucking bar has been placed on said shank end and
indicating to said rivet gun
operator that said bucking bar operator is ready to commence riveting; means
for driving the rivet
by forcing the shank against said bucking bar with said rivet set tool to form
a driven rivet head;
means for sensing when the height of said driven rivet head is substantially
equal to a desired set
rivet head height and indicating to both said bucking bar operator and said
rivet gun operator that
said desired set rivet head height has been achieved; and means for ceasing
driving the rivet when
said driven rivet height is substantially equal to said desired set rivet head
height. Said means for
driving may be a pneumatic rivet gun that is controlled by a solenoid valve,
and said system further
comprises: means for actuating said solenoid valve when said driven rivet head
height is
substantially equal to said desired set rivet head height to decouple said gun
from said air supply.
In another embodiment, there is provided a bucking bar for forming a rivet
head, said
.. bucking bar comprising: a housing having a cap and a cavity into which a
cylinder stem protrudes,
said cylinder stem having a distal shoulder; a plunger that is slidably
mounted in said cavity, said
plunger comprising a plunger stem that is mounted on said cylinder stem, said
plunger stem having
a plunger shoulder and a proximal shoulder; a compression spring that is
disposed within said
plunger stem and that has a first end that rests on said distal shoulder and a
second end that rests on
said proximal shoulder; a hammer that is slidably mounted in said plunger,
said hammer having an
anvil face at one end and being immovably attached to said housing at another
end. The bucking
bar may further comprise: a traveling nut that is disposed within said cavity
and around said
plunger stem, said traveling nut being held in position relative to said anvil
face by a micro-
adjustable jackscrew assembly; and a switch that is attached to said traveling
nut and that is
operative to change its state (e.g., to open or to close) when the position of
said plunger shoulder
relative to said switch indicates that a desired set rivet head height has
been achieved. The bucking
bar may further comprise: a wire that connects said switch to and between a
power supply and
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means for detecting when said desired set rivet head height has been achieved.
The bucking bar
may further comprise: a conducting post that is attached to said cap and
disposed in said cavity and
that passes through said traveling nut, said conducting post being in
electrical communication with
said anvil face; a bucking bar indicator light that is attached to the
exterior of said housing; a first
.. wire that connects said conducting post to means for detecting when said
anvil face is in contact
with the rivet shank; and a second wire that connects said bucking bar
indicator light to a ground;
wherein said bucking bar indicator light is operative to become illuminated
when said rivet gun
operator and said bucking bar operator are both ready to commence riveting.
Said plunger may
further comprise a shroud that surrounds said rivet head when said bucking bar
is in use. The
shroud's being bucked off because the anvil face gets bucked far away from the
forming rivet head
may be correctable by having the shroud extend farther past the anvil face and
requiring more
compressive force to be applied to the plunger for the bucker to indicate that
he is ready. Said
plunger may further comprise a spindles feet that extends through said hammer
and beyond said
anvil face.
In a further illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a shank, said rivet
being in conductive
communication with said work piece, said system comprising: a circuit
subassembly having a first
source of power and a bucker ready indicator light, said circuit subassembly
being in conductive
communication with said work piece; a rivet gun that is equipped with a rivet
set tool, said rivet
tool being in conductive communication with said circuit subassembly and
having a second source
of power; and a bucking bar system, said bucking bar system having a rivet gun
operator ready
indicator light that is in conductive communication with said circuit
subassembly; wherein said
rivet set tool is operative to impose a first voltage on said rivet
manufactured head when it is placed
in contact with said rivet manufactured head. The system may further comprise:
a switch that is
capable of isolating said second source of power from said rivet gun. The
system may further
comprise: a bucking bar control system comprising a microprocessor for
acquiring and processing
data relating to rivet driving; a power subsystem, a sensor array subsystem,
and a control and
communication subsystem. Said power subsystem may include rechargeable battery
and/or an
external power supply, and a power regulator. Said sensor array subsystem may
include a plurality
of bucking bar sensors and a plurality of rivet gun sensors. Said control and
communication
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subsystem may include a pneumatic solenoid having a controller, a plurality of
communication
indicators, a communication port, a graphical user interface and a keypad.
In another embodiment, there is provided a method for controlling a system for
setting a
rivet in a work piece with a rivet gun and a bucking bar, said method
comprising: initializing the
system; waiting to receive a second signal from a second sensor that indicates
that a rivet gun
operator is ready to commence riveting; when said first signal is received,
illuminating a rivet gun
operator indicator light and a bucking bar operator indicator light; waiting
to receive another
second signal from another second sensor that indicates that a bucking bar
operator is ready to
commence riveting; when said second signal is received, flashing said rivet
gun operator indicator
light and said bucking bar operator indicator light on and off; optionally,
starting a first user
selectable time delay; enabling the operation of said rivet gun by actuating a
solenoid coupling said
rivet gun to an air supply source; beginning a rivet setting operation;
sensing that said rivet setting
operation has begun and then starting a timer, counting the number of impact
blows from the rivet
gun and waiting to receive a rivet head height threshold detection signal;
when said rivet head
height threshold detection signal is received, stopping the rivet gun, stops
said timer, turning off
said indicator lights and, optionally, starting a second user selectable time
delay. The method may
further comprise: determining strength of the rivet, displaying a recommended
rivet gun air
regulator setting and logging a set rivet head height.
In another illustrative embodiment, there is provided a bucking bar for
forming a rivet
head, said bucking bar comprising: a housing having a cavity and comprising a
housing shoulder; a
plunger that is slidably mounted in said cavity and that is held within said
cavity by said housing
shoulder, said plunger comprising a plunger stem that has a proximal shoulder;
a cap screw that is
mounted on said proximal shoulder; a hammer that is slidably mounted in said
plunger, said
hammer having an anvil face at one end and a cap at another end; a compression
spring that is
disposed within said cavity and that has a first end that rests on said cap
and a second end that rests
on said proximal shoulder. The bucking bar may further comprise: a photo
switch that is mounted
on said housing within said cavity, said photo switch being operative to
actuate or toggle states
when said cap screw is detected by said photo switch.
In another illustrative embodiment, there is provided a backriveting system,
said
backriveting system comprising: a plunger comprising a proximal shoulder and
having a cavity; an
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internal collar that is slidably movable within said cavity; a rivet set tool
having a set tool stem that
extends through said cavity and through said internal collar, said rivet set
tool having one end
having an anvil face and another end being attachable to a rivet gun and said
set tool stem being
fixed to said internal collar; a compression spring having a first end that
rests on said internal collar
and a second end that rests on said proximal shoulder; an exterior collar that
is attachable to said
stem; and a switch that is attached to said plunger and that is operative to
actuate or toggle states
when the position of said exterior collar relative to said switch indicates
that a desired set rivet head
height has been achieved or (alternatively) when said switch indicates that a
rivet gun operator is
ready to begin riveting.
In yet another illustrative embodiment, there is provided a bucking bar for
forming a rivet
head on a rivet in a work piece, said bucking bar comprising: a housing having
a cavity having an
interior surface upon which is provided a key or axially-positioned tab; a
first embedded switch
that is embedded in said housing; a plunger that is slidably mounted in said
cavity, said plunger
comprising a plunger stem that has exterior threads, a proximal shoulder, a
collar and a shroud; a
traveling nut that has interior threads that are operative to engage with said
exterior threads on said
plunger, said traveling nut having a groove that is operative to engage with
said said key or axially
positioned tab to achieve axial slidable movement of said traveling nut; a
hammer, a portion of
which is mounted in said plunger, said hammer having an anvil face at one end
and a cap at another
end; a switch housing collar that is mounted within said cavity; a second
embedded switch that is
attached to said switch housing collar; and a compression spring that is
disposed within said cavity
and that has a first end that rests on said switch housing collar and a second
end that rests on said
proximal shoulder; wherein said first embedded switch is operative to toggle
switch state when said
collar of said plunger moves axially upward relative to said housing; and
wherein said second
embedded switch is operative to toggle switch state when the position of said
traveling nut relative
to said switch indicates that a desired set rivet head height has been
achieved. The bucking bar may
further comprise: three electrical conducting contact points disposed about
120 degrees apart
around said shroud; a wire connecting each of said electrical conducting
contact points to a
microprocessor that is operative to detect which of said three electrical
conducting contact points
are resting on said work piece. The bucking bar may further comprise: three
indicator lights
disposed about 120 degrees apart around said shroud, any number of said three
indicator lights
being operative to illuminate if directed to do so by said microprocessor. The
bucking bar may
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further comprise: three electrical conducting contact points disposed about
120 degrees apart
around said shroud; a wire connecting each of said electrical conducting
contact points to a
microprocessor that is operative to detect which of said three electrical
conducting contact points
are resting on said work piece. The bucking bar may further comprise: three
indicator lights
.. disposed about 120 degrees apart around said shroud, any number of said
three indicator lights
being operative to illuminate if directed to do so by said microprocessor.
In another illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a rivet shank, said
system comprising: a
rivet gun having a rivet set tool that is energized by a pressurized fluid
that must pass through a
solenoid valve, said solenoid valve having a first port through which said
pressurized fluid enters
said solenoid valve and a second port through which said pressurized fluid
must pass to reach said
rivet gun; an augmented bucking bar having a contact; a first source of direct
current that is
disposed in a first normally open electrical circuit that also includes a
first work piece, a first
indicator light and said rivet set tool connected in series, said first source
of direct current being
operative to illuminate said first indicator light when said rivet set tool is
placed in contact with
said rivet manufactured head; a second source of direct current that is
disposed in a second
normally open electrical circuit that also includes a second work piece, a
second indicator light and
said augmented bucking bar connected in series, said second normally open
electrical circuit also
being connected to a relay, said second source of direct current being
operative to illuminate said
second indicator light when said augmented bucking bar is placed in contact
with said rivet shank;
a third source of direct current that is disposed in a third normally open
electrical circuit that also
includes said second work piece, said relay and said contact connected in
series, said third source
of direct current being operative to actuate said relay when said contact is
brought in contact with
said second work piece during a riveting cycle (operatively, this circuit is
formed when the driven
rivet height is substantially equal to the desired set rivet head height); and
a fourth source of direct
current that is disposed in a fourth normally open electrical circuit that
also includes said relay and
said solenoid valve, said fourth source of direct current being operative to
close said first port of
said solenoid valve when said relay is actuated. Said solenoid valve may be a
three-port solenoid
valve comprising a third port that is connected to an ambient atmosphere and
said fourth source of
direct current being operative to close the first port and open the second
port and said third port of
CA 2892774 2018-01-08

said solenoid valve when said relay is actuated, thereby allowing backpressurc
from said rivet gun
to be exhausted from the rivet gun to said ambient atmosphere.
In yet another illustrative embodiment, there is provided a method for
controlling a system
for setting a rivet in a work piece with a rivet gun that is operated by a
rivet gun operator and a
bucking bar that is operated by a bucking bar operator, said method
comprising: initializing system
components and disabling the rivet gun; conducting system tests, comprising
detecting whether the
rivet gun operator is ready to begin riveting, detecting whether the bucking
bar operator is ready to
begin bucking and monitoring the system for system errors; turning system LEDs
on, including
turning on the bucking bar operator's LED to indicate the bucking bar operator
that the rivet gun
operator is ready to begin riveting and turning the rivet gun operator's LED
on to verify that the
bucking bar operator's LED has been turned on; detecting that the bucking bar
operator is ready to
begin bucking, enabling the rivet gun and flashing said LEDs on-and-off to
indicate to both
operators that the bucking bar operator is ready to begin bucking, continuing
to monitor the system
for said system errors and for calibration requests and disabling the rivet
gun when desired set rivet
head height has been achieved; if one of said system errors is detected,
ceasing riveting and
informing the operators of the error condition; if a calibration request is
received, allowing at least
one of said operators to calibrate the system; and resetting the system. Said
conducting system tests
step may further comprise: detecting whether a rivet head height detection
sensor is working,
determining whether the rivet gun operator has set up on a rivet and then
disengaged, determining
whether the bucker has removed the bucking bar from the rivet, detecting
whether a calibration
mode has been requested by one of the operators or alternately by the system,
and detecting when a
system reset is requested by at least one of the operators or by the system
following the end of a
rivet driving cycle, following operation of an error management subroutine, or
following operation
of a calibration management subroutine. The method may further comprise:
counting the number
of rivets driven and invoking an automatic calibration check after the system
is used to set a
predetermined number of rivets. The method may further comprise: counting the
number of
impacts it takes to set a rivet and/or measuring each rivet setting time.
In another illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a rivet shank, said
system comprising: a
rivet gun having a rivet set tool that is wired to a first circuit subassembly
that is wired to a first
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work piece, said rivet set tool being operative to generate a first signal
when it is placed on the rivet
manufactured head; a bucking bar that is wired to or integral with a second
circuit subassembly that
is in radio frequency communication with said first circuit subassembly, or
that is in radio
frequency communication with a third circuit subassembly that is in radio
frequency
communication with said first circuit subassembly, said bucking bar being
operative to generate a
second signal when it is placed on the rivet shank and being operative to
generate a third signal
when the rivet is set; a solenoid valve that is wired to a fourth circuit
subassembly that is in radio
frequency communication with said first circuit subassembly, or that is in
radio frequency
communication with a third circuit subassembly that is in radio frequency
communication with said
first circuit subassembly, said solenoid valve being operative to enable and
disable said rivet gun; a
microprocessor or data logger that is wired to a fifth circuit subassembly
that is in radio frequency
communication with said first circuit subassembly and said second circuit
subassembly, or that is
in radio frequency communication with a third circuit subassembly that is in
radio frequency
communication with said first circuit subassembly and said second circuit
subassembly, said
microprocessor or data logger being operative to monitor productivity. The
system may further
comprise: a pressure regulator that is wired to a sixth circuit subassembly
that is in radio frequency
communication with at least one of said first circuit subassembly, said second
circuit subassembly,
said third circuit subassembly, said fourth circuit subassembly and said fifth
circuit subassembly,
said pressure regulator being operative to control the pressure being imposed
on said solenoid
valve and, thereby, on said rivet gun. A person having ordinary skill in the
art would understand
that any means of radio communication could be used to accomplish this
function.
In yet another illustrative embodiment, there is provided a method for setting
a rivet in a
work piece, said method comprising: attaching a sensor pad having a thickness
equal to a desired
rivet head height to said work piece; driving a rivet having a rivet
manufactured head and a rivet
shank by forcing said rivet shank against a bucking bar with a rivet gun to
produce said driven rivet
head having a height; determining whether said height is substantially equal
to a desired set rivet
head height; and ceasing driving said rivet when said height is equal to said
desired rivet head
height. Said bucking bar being held by a bucker and said rivet gun may be held
by a rivet gun
operator, and said method may further comprise: prior to said driving step,
transmitting a rivet gun
operator ready signal to said bucker when said rivet gun contacts said rivet
manufactured head,
thereby indicating to said bucker that said rivet gun operator is ready; and
transmitting a bucker
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ready signal to said rivet gun operator after sensing when said bucking bar
contacts said rivet
shank, thereby indicating to said rivet gun operator that said bucker is
ready. The method may
further comprise: prior to said ceasing step (described above), transmitting
an end of riveting cycle
signal to said rivet gun operator when said bucking bar contacts said sensor
pad. The method may
.. further comprise: applying a force to said work piece after said rivet gun
operator ready signal is
transmitted and before said bucker ready signal is transmitted. Said bucking
bar contacting said
rivet shank may be accomplished by the bucker's compressing a spring loaded
plunger that is
applying a force to said work piece.
In yet another illustrative embodiment, there is provided a system for setting
a rivet in a
work piece, said system comprising: means for driving a rivet having a rivet
manufactured head
and a rivet shank by forcing said rivet shank against a bucking bar with a
rivet gun to produce said
driven rivet head having a height; means for determining whether said height
is substantially equal
to a desired set rivet head height; and means for ceasing driving said rivet
when said height is equal
to said desired rivet head height.
In another illustrative embodiment, there is provided a method for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a shank having a shank
end, said method
comprising: sensing when a rivet set tool of a rivet gun has been placed in
electrical
communication with the rivet and indicating that said rivet set tool is ready;
sensing when a
bucking bar has been placed in electrical communication with the rivet and
indicating that said
bucking bar is ready; driving the rivet by forcing the shank against said
bucking bar with said rivet
set tool to form a driven rivet head; determining when the height of said
driven rivet head is
substantially equal to a desired set rivet head height and indicating that
said desired set rivet head
.. height has been achieved; and ceasing driving the rivet. Said sensing steps
and/or determining step
may comprise: completing electrical circuits. Said indicating step may
comprise turning lights on
or off and/or flashing lights on and off. Said determining step may further
comprise disabling said
rivet gun. Said disabling step may comprise actuating a solenoid valve on a
compressed air line
from a compressed air source to said rivet gun to decouple said rivet gun from
said compresses air.
Said driving step may comprise forcing an anvil face against the shank and
simultaneously pushing
a plunger having a shoulder and a base against the work piece, thereby causing
said anvil face to
move toward said base as said driven rivet head is formed. Said forcing step
may comprise
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compressing a spring that urges said base against said work piece when said
anvil face is forced
against said shank. Said determining step (described above) may comprise
sensing when said
shoulder or said base is displaced away from a plane containing at least a
portion of said anvil face
a selected distance. One or more of said indicating steps may comprise a radio
frequency
communication. The method may further comprise monitoring contact between said
bucking bar
and the rivet shank and counting hammer blows during the driving step.
In yet another illustrative embodiment, there is provided a method for setting
a rivet in a
work piece, said rivet having a rivet manufactured head and a shank having a
shank end, said
method comprising: a step for sensing when a rivet set tool of a rivet gun has
been placed in
electrical communication with the rivet and indicating that said rivet set
tool is ready; a step for
sensing when a bucking bar has been placed in electrical communication with
the rivet and
indicating that said bucking bar is ready; a step for driving the rivet by
forcing the shank against
said bucking bar with said rivet set tool to form a driven rivet head; a step
for determining when
the height of said driven rivet head is substantially equal to a desired set
rivet head height and
indicating that said desired set rivet head height has been achieved; and a
step for ceasing driving
the rivet.
In another illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a shank having a shank
end, said system
comprising: means for sensing when a rivet set tool of a rivet gun has been
placed in electrical
communication with the rivet and indicating that said rivet set tool is ready;
means for sensing
when a bucking bar has been placed in electrical communication with the rivet
and indicating that
said bucking bar is ready; means for driving the rivet by forcing the shank
against said bucking bar
.. with said rivet set tool to form a driven rivet head; means for determining
when the height of said
driven rivet head is substantially equal to a desired set rivet head height
and indicating that said
desired set rivet head height has been achieved; and means for ceasing driving
the rivet.
In yet another illustrative embodiment, there is provided a system for
determining when a
rivet gun set tool contacts a manufactured head and when an anvil face of a
bucking bar tool
contacts a rivet shank, said system comprising: means for determining when the
rivet gun set tool
contacts the manufactured head and when the anvil face of the bucking bar tool
contacts the rivet
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shank that are incorporated into said rivet gun set tool and/or into the
bucking bar tool; and means
for informing an operator when the rivet gun set tool contacts the
manufactured head and when the
anvil face of the bucking bar tool contacts the rivet shank.
In another illustrative embodiment, there is provided a system for fastening a
rivet in a
work piece with a rivet driver, the workpiece having a work surface, said
rivet having a
manufactured head, a shank, and a shank end, the shank and shank end nominally
projecting from
said work surface, said system comprising: an anvil having an anvil face; a
plunger slidably
engaged with said anvil, said plunger having a distal end, said distal end
nominally extending
beyond said anvil face; a load source that is operative to nominally urge said
5 plunger distal end
forward relative to said anvil face to maintain contact with a work surface; a
first sensor that is
operative to sense the distance between a work surface and said anvil face and
produce a first input
signal related to said distance; a control subsystem comprising a controller;
said controller
subsystem operative to enable and disable a rivet driver; and receive said
first input signal from
said first sensor and send an output signal to the controller, and disable a
rivet driver when said
distance is substantially equal to a desired rivet head height. In another
embodiment, the system
further comprises: a second sensor that is operative to produce a second input
signal when said
anvil face first contacts a shank end; a third sensor that is operative to
sense said distance and
produce a third input signal related to said distance and representative of a
shank length nominally
projecting from said work surface upon said first contact; and wherein said
control subsystem is
operable to: receive said second input signal and said third input signal;
store said distance;
determine said desired rivet head height; and store said desired rivet head
height. In another
embodiment, the system further comprises: a third sensor that is operative to
produce a third input
signal when said anvil face first contacts a shank end; and wherein said
control subsystem: receives
said third input signal; and is operative to determine when said anvil face
makes said first contact
with a shank end, store said distance, determine said desired rivet head
height, and store said
desired rivet head height. In another embodiment, the system further
comprises: a second sensor
that is operative to produce a second input signal when said anvil face first
contacts a shank end;
wherein said control subsystem receives said second input signal and produces
a second output
signal that indicates that said anvil face is in contact with a shank end. In
another embodiment, the
system further comprises: a second sensor that is operative to produce a
second input signal when
the rivet driver first contacts a manufactured head or a shank end; wherein
said control subsystem
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receives said second input signal and produces a second output signal that
indicates that the rivet
driver is in contact with a manufactured head or a shank end. In another
embodiment, the system
further comprises a second sensor that is operative to produce a second input
signal when the rivet
driver contacts one of a manufactured head or a shank end or said anvil face
contacts the other of a
manufactured head or a shank end. In another embodiment, said control
subsystem receives said
second input signal and is operative to activate a visual signal, said visual
signal being operative to
provide a communication to a user. In another embodiment, said control
subsystem receives said
second input signal and is operative to determine a damage event condition and
to operate said
controller to disable a rivet driver when said damage event condition is
determined. In another
embodiment, said control subsystem receives said second input signal and is
operative to indicate
to a user that both a rivet driver and said anvil face are in contact with a
rivet. In another
embodiment, the system further comprises: a fourth sensor having a plurality
of spindles feet at the
distal end of said plunger, said fourth sensor being operative to produce a
fourth input signal that
characterizes whether said plurality of spindles feet are substantially in
contact with a work
surface; wherein said control subsystem receives said fourth input signal and
is operative to
determine when said anvil face is not approximately perpendicular to a shank
or parallel to the
work surface and produce a fourth output signal that indicates a need for a
tool alignment
correction or causes said controller to disable the rivet driver. In another
embodiment, said control
subsystem is also operative to activate a visual signal based on said fourth
input signal, said visual
signal providing a communication to a user. In another embodiment, the system
further comprises:
a plurality of electrical conducting contact points disposed about the distal
end of said plunger; and
a circuit connecting 5 said electrical conducting contact points to the
control subsystem, said
control subsystem being operative to detect which of said electrical
conducting contact points are
resting on a work surface. In another embodiment, the system further comprises
a plurality of
indicator lights disposed about said plunger, any number of said indicator
lights being operative to
illuminate if directed to do so by said control subsystem; wherein said
indicator lights arc
illuminated in a fashion to communicate a tool alignment position correction
relative to a work
surface. In another embodiment, said control subsystem receives said first
input signal and is
operative to determine a desired rivet head height. In another embodiment, the
system further
comprises: a user input device that is operative to receive input from a user;
wherein said first
sensor is an analogue sensor; and wherein said control subsystem is operative
to receive said
desired rivet head height from said user input device. In another embodiment,
the system further
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comprises: a memory; an addressable communication capability between at least
two control
subsystems; a central computer having central memory, said central computer in
communication
with or comprised of at least one control subsystem; wherein said at least one
control subsystem is
operable to transfer a data set of riveting information to said central
memory; and wherein said
central memory stores said data set. In another embodiment, the system further
comprises: a data
base operating on said central computer, said central computer being operative
to receive a
plurality of said data sets from said control subsystems and store them in
said data base. In another
embodiment, the system further comprises: a valve to enable and disable said
rivet driver; said
valve comprising: an input coupled to a power source, an output coupled to
said rivet driver; and
.. wherein said control subsystem disables said rivet driver by actuating said
valve, or said control
subsystem enables said rivet driver by actuating said valve, thereby coupling
a power source to said
rivet driver. In another embodiment said first sensor has a switching
threshold; whereby a 25
physical feature on said plunger actuates the switching threshold of said
first sensor when plunger
is axially displaced said distance representative to a desired rivet head
height. In another
.. embodiment, the system further comprises an adjustable mechanism that is
operative to allow said
first sensor to be adjusted so that said switching threshold toggles when said
distance is
substantially equal to said desired rivet head height. In another embodiment,
the system further
comprises: a user input device that is operative to receive an input from a
user; wherein said control
subsystem is operative to receive said input representing a known distance
between the work
.. surface and said anvil face for use in calibrating said first sensor. In
another embodiment, the
system further comprises: an impact sensor that is operative to sense, and
produce a second input
signal when a rivet driver produces an impact on a rivet; and wherein said
control subsystem
receives said impact sensor second input signal and is operative to determine
an impact event and
store a tally of said impacts. In another embodiment, the system further
comprises: a third sensor
that is operative to produce a third input signal when said anvil face first
contacts a shank end, said
third input signal being related to a shank length extending between said
anvil face and the work
surface; and an indicator that is operative to indicate a level of impact
power transmitted from a
rivet driver based on said shank length; wherein said control subsystem also
receives said third
input signal and is operative to determine a rivet size, then determine if
said tally approximately
corresponds to a rivet gun impact power substantially needed to set said rivet
to a desired rivet
head height using a predetermined number of rivet driver impacts according to
a shank length. In
another embodiment, said control subsystem is also operative to: keep a count
of the number of
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rivets set by a rivet driver; compare said count to a predetermined number;
and indicate when said
count and said predetermined number are substantially equal. In another
embodiment, the system
further comprises: a user interface device that is operative to receive an
input from a user and to
provide an output to said user; and wherein said control subsystem is
operative to determine an
.. offset distance and notify said user of said offset distance, said offset
distance being a difference
between a first measure and a second measure, said first measure being
indicated by said first
sensor when a first known distance is sensed between the work surface and the
anvil face before a
recalibration of the rivet driver and said second measure being indicated by
said first sensor when a
first known distance is sensed between the work surface and the anvil face
upon a recalibration of
the rivet driver. In another embodiment, said control subsystem is also
operative to indicate that the
system for fastening a rivet requires refurbishment or replacement when said
offset distance
exceeds a specified level. In another embodiment, said control subsystem is
operative to analyze
said first input signal to assess plastic deformation of the shank in
determining when said distance
is substantially equal to a desired rivet head height.
In yet another illustrative embodiment, there is provided a system for
fastening a rivet in a
work piece with a rivet driver, the work piece having a work surface, the
rivet having a shank and a
shank end, said system comprising: means for setting a rivet to create a rivet
head, said setting
means (i.e., means for setting) having an anvil face; means for contacting a
work surface having a
contact point, said contact point extending beyond said anvil face; urging
means (i.e., means for
urging) to urge said contact point to maintain contact with a work surface;
first sensing means
operable to sense the distance between a work surface and said anvil face and
to produce a first
input signal related thereto; and controlling means (i.e., means for
controlling) operable to enable
and disable the rivet driver. In another embodiment, the system further
comprises: means for
computing that receives said input signal from said first sensing means and
sends an output signal
to said control means, said means for computing being operative to actuate
said control means to
disable the rivet driver when said distance is substantially equal to a
desired rivet head height. In
another embodiment, the system further comprises: second sensing means
operable to produce a
second input signal when said means for setting a rivet first contacts a shank
end; means for storing
data; means for computing that receives said first input signal and said
second input signal, said
computing means is operative: to store said distance as data in said means for
storing; to determine
a desired rivet head height; to store a desired rivet head height as data in
said means for storing
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when said second input signal is received; and to send an output signal to
said control means to
disable a rivet driver when said distance is substantially equal to a desired
rivet head height. In
another embodiment, said second sensing means is operative to produce a second
input signal
when said anvil face first contacts a shank end; and said means for computing
receives said second
input signal and produces a second output signal that indicates that said
anvil face is in first contact
with a shank end. In another embodiment, the system further comprises a fourth
sensing means
comprising a plurality of spindles feet, said fourth sensing means being
operative to produce a
fourth input signal that indicates whether said plurality of spindles feet are
resting on a work
surface; and wherein said means for computing receives said fourth input
signal, determines when
said anvil face is not substantially perpendicular to the shank or
substantially parallel to the work
surface, and produces a third output signal that indicates a need for a tool
alignment correction or
that actuates a controller to disable a rivet driver. In another embodiment,
said means for
computing receives 5 said second input signal and produces said second output
signal that indicates
that both the rivet driver and said anvil face are in first contact with the
rivet. In another
embodiment, said second sensing means is operative to produce said second
input signal each time
said anvil face contacts the shank end and said means for computing is
operative to determine
whether an impact from the rivet driver has occurred and count said impacts.
In a further illustrative embodiment, there is provided a system for fastening
a rivet in a
work piece with a rivet driver, the rivet having a manufactured head, a shank
and a shank end, the
work piece having a work surface, said system comprising: an anvil having an
anvil face; a plunger
having a distal end, said distal end extending beyond said anvil face; a load
source that is operative
to urge said distal end to maintain contact with the work surface; a first
sensor that is operative to
sense the distance between the work surface and said anvil face and produce a
first input signal
related to said distance; a second sensor that is operative to produce a
second input signal when
said anvil face first contacts the shank end; a memory; a controller that is
operative to enable and
disable the rivet driver; and a microprocessor that receives said first input
signal and said second
input signal, is operative to: store said distance in said memory; determine a
desired rivet head
height; store said desired rivet head height in said memory when said second
input signal is
received; and send an output signal to said controller to disable the rivet
driver when said distance
is substantially equal to a desired rivet head height. In another embodiment,
said second sensor is
also operative to produce a second input signal when the rivet driver first
contacts one of the
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manufactured head or the shank end or when said anvil face first contacts the
other of the
manufactured head or the shank end.
In another illustrative embodiment, there is provided a method for fastening a
rivet having
a shank and a shank end, in a work piece having a work surface with a system
comprising a rivet
driver, a controller that is operative to enable and disable the rivet driver,
a microprocessor that is
operative to control controller, a plunger having a contact point, a load
source that is operative to
urge said contact point to maintain contact with the work surface, an anvil
having an anvil face, and
a first sensor that is operative to sense the distance between the work
surface and said anvil face,
said method comprising: placing the plunger against the work surface and
applying a load to the
plunger that is operative to load the load source until the anvil face
contacts a shank end; driving
the rivet with the rivet driver; with the first sensor, sensing the distance
between the work surface
and the anvil face and generating a first input signal related to such
distance; with the
microprocessor, receiving said first input signal from the first sensor,
determining when said
distance is substantially equal to a desired rivet head height, and then
actuating the controller to
disable the rivet driver. In another embodiment, the system further comprises
a second sensor, and
said method further comprises: with the second sensor, generating a second
input signal when the
anvil face first contacts the shank end; and with the microprocessor:
receiving said second input
signal and generating a second output signal that indicates that said anvil
face is in first contact
with the shank end; or, receiving said second input signal and determining a
desired rivet head
height based on said distance. In another embodiment, the method further
comprises applying a
load to the work piece with said plunger, said load being operative to
minimize any air gap existing
between a plurality of work pieces.
In another illustrative embodiment, there is provided one or more rivets
produced in
accordance with a method disclosed herein.
In yet another illustrative embodiment, there is provided a system for
fastening a rivet in a
work piece with a rivet driver that is operative to produce a plurality of
hammer impacts, said
system comprising: an anvil having an anvil face for delivering a hammer
impact against the rivet;
an impact sensor that is operative to sense when said hammer impact occurs or
sense the duration
of operation of the rivet driver, and produce an input signal related to an
impact count; a
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microprocessor; a memory; a controller that is operative to enable and disable
the rivet driver;
wherein said microprocessor receives said input signal, and is operative to
determine when a
desired number of hammer impacts has occurred or when a desired duration of
operation has
occurred and then to actuate said controller to disable the rivet driver; and
wherein said controller
disables the rivet driver when a distance between a work surface and the anvil
face substantially
equals a desired rivet head height. In another embodiment, the system further
comprises: a rivet
driving information, said rivet driving information being obtained from the
impact sensor or from a
user input and selected from the group consisting of: a rivet driver hammer
period or frequency, a
nominal rivet size, a rivet material, a desired number of hammer impacts, and
a nominal rivet
1 0 .. driving power regulator setting; and wherein the microprocessor is
operative to disable the rivet
driver when the impact count is substantially equal to a desired number of
impacts or the rivet
driver hammering duration is substantially equal to a desired duration needed
to set rivet to a
desired rivet head height.
In another illustrative embodiment, there is provided a method for setting a
rivet in a work
piece with a rivet driver, said rivet having a rivet manufactured head and a
shank having a shank
end, said method comprising: sensing when a rivet driver anvil face has been
placed on the rivet
manufactured head or the shank end and indicating that a rivet driver is ready
to commence
riveting; sensing when a bucking bar anvil face has been placed on the shank
end and indicating
.. that the bucking bar is ready to commence riveting; driving the rivet by
forcing the shank against
said bucking bar anvil face with said rivet driver anvil face to form a driven
rivet head; sensing
when the height of said driven rivet head is substantially equal to a desired
predetermined rivet
head height; and ceasing driving the rivet when the height of said driven
rivet head is substantially
equal to said desired predetermined rivet head height. In another embodiment,
said operation of the
rivet driver is controlled by a valve, and said method further comprises:
first actuating said valve
when said driven rivet head height is substantially equal to said desired
predetermined rivet head
height to operatively decouple the rivet driver from a power supply source and
stop riveting; and
second actuating the valve to operatively couple the rivet driver to the power
supply source when
the rivet driver operator and a bucking bar operator are both ready to start
setting a subsequent
rivet.
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In yet another illustrative embodiment, there is provided a system for setting
a rivet in a
work piece, said rivet having a rivet manufactured head and a shank having a
shank end, said
system comprising: means for sensing when a rivet set tool has been placed on
the rivet
manufactured head or the shank end and indicating to a bucking bar operator
that a rivet gun
operator is ready to commence riveting; means for sensing when a bucking bar
has been placed on
the shank end and indicating to the rivet gun operator that the bucking bar
operator is ready to
commence riveting; means for driving the rivet by forcing the shank against
the bucking bar with
the rivet set tool to form a driven rivet head; and means for ceasing driving
the rivet when the
driven rivet head height is substantially equal to the desired set rivet head
height. In another
embodiment, said means for driving is a rivet gun that is controlled by a
valve; and said system
further comprises: means for actuating said valve when the driven rivet head
height is substantially
equal to the desired set rivet head height to operatively decouple the rivet
gun from a power supply
source effectuating disabling the rivet gun; and means for subsequently
actuating the valve to
operatively couple the rivet gun to the power supply source when the rivet gun
operator or the
bucking bar operator is ready to commence setting a further rivet by
effectuating enabling the rivet
gun.
In another illustrative embodiment, there is provided an anvil for forming a
rivet head on a
rivet shank, said anvil comprising: a housing having portions defining a
cavity, a cap portion at one
end of said cavity and a cylinder stem protrudes from the cap into said
cavity; a plunger that is
slidably mounted in said cavity, said plunger comprising a plunger stem that
is slidable relative to
said cylinder stem; a resilient loading device acting between said housing and
said plunger to urge
said plunger away from the cap portions of said housing; a hammer that is
mounted within said
plunger, said hammer having a hammer stem connected to the cap portion of said
housing, and an
anvil face carried by said hammer stem opposite the location, that the hammer
stem is attached to
said housing. In another embodiment, the anvil further comprises: an
adjustable position sensor to
sense the position of said plunger, said position sensor being held in
position relative to said anvil
face by a micro-adjustable assembly; a state sensor coordinating with said
micro-adjustable
assembly, said state sensor operative to change its state when the position of
said plunger relative
to said state sensor indicates that a desired set rivet head height has been
achieved. In another
embodiment, the anvil further comprises a bucking bar having an anvil for
forming the rivet head
on the rivet in a work piece, said bucking bar comprising: a key or axially-
positioned tab located in
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cavity of said housing; a first switch that is in said housing; said plunger
further comprising: a
plunger stem that has exterior threads, a proximal shoulder, a collar, and a
shroud; a traveling nut
that has interior threads that are operative to engage with said exterior
threads on said plunger, said
traveling nut having a longitudinal groove that is operative to engage with
said key or axially-
positioned tab to achieve axial slidable movement of said traveling nut along
said plunger; a switch
housing collar that is mounted within said cavity; a second switch that is
attached to at least one of
said switch housing collar, said housing, and said cap; and a resilient
loading device disposed
within said cavity further comprising: a first end that rests on said switch
housing collar or on said
cap and a second end that rests on said proximal shoulder; wherein said first
embedded switch is
operative to toggle switch state when said collar of said plunger moves
axially upward relative to
said housing, thereby operably indicating when bucking bar operator is ready
to begin bucking; and
wherein said second switch is operative to toggle switch state when the
position of said traveling
nut relative to said switch indicates that a desired set rivet head height has
been achieved. In
another embodiment, the anvil further comprises: a microprocessor; a first
conducting path
providing electrical communication from said microprocessor to said anvil
face; a second
conducting path providing electrical communication from said microprocessor to
a work piece; a
visual indicator attached to 5 said housing; a loop circuit sensor for
detecting when said anvil face
is in contact with a rivet shank or for detecting when said anvil face is not
in contact with a rivet
shank; and a third conductor path that connects said visual indicator to a
ground and to a power
source; said microprocessor controlling the operation of said visual indicator
to communicate to a
rivet gun user or a bucking bar user the driving stage of the rivet setting
process; wherein said
visual indicator is operative to become illuminated in a first fashion when
the rivet gun user is
ready to commence riveting and in a second fashion when a rivet gun operator
and a bucking bar
user are both ready to commence riveting. In another embodiment said plunger
further comprises a
shroud that surrounds said rivet head when said anvil is in use; said shroud
encircling said anvil
face. In another embodiment, said plunger further comprises a spindles feet
located at the distal end
of said plunger that nominally extend beyond the plane of said anvil face to
rest on a work surface.
In a further illustrative embodiment, there is provided a method for
controlling a system for
setting a rivet in a work piece with a rivet gun and a bucking bar, said
method comprising:
initializing the system; waiting to receive a first signal from a first sensor
that indicates that a rivet
gun operator is ready to commence riveting; when said first signal is
received, activating in a first
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fashion a rivet gun operator ready indicator; waiting to receive a second
signal from a second
sensor that indicates that a bucking bar operator is ready to commence
riveting; when said second
signal is received, activating in a second fashion a bucking bar operator
ready indicator; optionally,
starting a first user selectable time delay; enabling the operation of the
rivet gun by actuating a
switch coupling the rivet gun to a power supply source; beginning a rivet
setting operation; sensing
that the rivet setting operation has begun and then optionally determining the
number of impact
blows from the rivet gun and waiting to receive a rivet head height threshold
detection signal; when
the rivet head height threshold detection signal is received, stopping the
rivet gun by decoupling
the rivet gun from the power supply source and optionally stopping the timer
or starting a second
user selectable time delay. In another embodiment, the method further
comprises: determining a
strength of the rivet; displaying a recommended rivet gun power level setting
and/or adjusting a
rivet gun power level setting; and optionally storing in a data memory device
a set rivet head height
and/or rivet set strength.
In another illustrative embodiment, there is provided a method for controlling
a system for
setting a rivet in a work piece with a rivet gun that is operated by a rivet
gun operator and a
bucking bar that is operated by a bucking bar operator, said method
comprising: initializing system
components and disabling the rivet gun; conducting system tests, comprising
detecting whether the
rivet gun operator is ready to begin riveting, detecting whether the bucking
bar operator is ready to
begin bucking and monitoring the system for system errors; activating a
plurality of system visual
indicators in a first fashion, including activating a bucking bar operator's
visual indicator to
indicate to the bucking bar operator that the rivet gun operator is ready to
begin riveting and/or
activating a rivet gun operator's visual indicator to notify to the rivet gun
operator that a signal has
been sent to the bucking bar operator that the rivet gun operator is ready to
begin riveting; detecting
that the bucking bar operator is ready to begin bucking, enabling the rivet
gun and activating a
plurality of system visual indicators in a second fashion to notify both
operators that the bucking
bar operator is ready to begin bucking; continuing to monitor the system for
said system errors and
for requests to calibrate system components and disabling the rivet gun 5 when
the desired set rivet
head height has been achieved; if one of said system errors is detected,
ceasing riveting and
informing the operators of the error condition; if a calibration request is
received, allowing at least
one of said operators to calibrate the system; and resetting the system. In
another embodiment, said
conducting system tests step further comprises at least one of: detecting
whether a rivet head height
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detection sensor is working; determining whether the rivet gun operator has
set up on a rivet and
then disengaged; determining whether the bucking bar operator has removed the
bucking bar from
the rivet; detecting whether a calibration mode has been requested by one of
the operators or
alternately by the system; and detecting when a system reset is requested by
at least one of the
operators or by the system following the end of a rivet driving cycle. In
another embodiment, the
method further comprises: counting the number of rivets set and invoking an
automatic calibration
after the system is used to set a predetermined number of rivets. In another
embodiment, the
method further comprises counting the number of impacts it takes to set a
rivet and/or measuring
each rivet setting time duration.
In another illustrative embodiment there is provided a method for setting a
rivet in a work
piece, said method comprising: attaching a sensor pad having a thickness equal
to a desired rivet
head height one of the work piece or a bucking bar anvil face; driving a rivet
having a rivet
manufactured head and a rivet shank by forcing the rivet shank against the
bucking bar anvil face
.. with a rivet gun to produce the driven rivet head having a height;
determining whether the height is
substantially equal to a desired set rivet head height; and ceasing driving
the rivet when the height
is equal to the desired rivet head height; whereby the sensor pad actuates a
switch when said height
is substantially equal to a desired set rivet head height. In another
embodiment, the bucking bar is
being held by a bucker and the rivet gun is being held by a rivet gun
operator, and said method
.. further comprises: prior to said driving step, transmitting a rivet gun
operator ready signal to the
bucker when the rivet gun contacts the rivet manufactured head, thereby
indicating to the bucker
that the rivet gun operator is ready; and transmitting a bucker ready signal
to the rivet gun operator
after sensing when the bucking bar contacts the rivet shank, thereby
indicating to the rivet gun
operator that the bucker is ready.
In yet another illustrative embodiment, there is provided a system for setting
a rivet in a
work piece, said system comprising: means for sensing when a rivet set tool
has been placed on a
rivet manufactured head or a shank end and indicating to a bucking bar
operator that a rivet gun
operator is ready to commence riveting; means for sensing when an anvil has
been placed on the
shank end and indicating to the rivet gun operator that the bucking bar
operator is ready to
commence riveting; means for driving a rivet having the rivet manufactured
head and a rivet shank
having the shank end by forcing the rivet shank end against the anvil with a
rivet gun to produce a
CA 2892774 2018-01-08

driven rivet head having a height; means for determining whether the height is
substantially equal
to a desired set rivet head height; and means for ceasing driving said rivet
when the height is equal
to the desired rivet head height.
In another illustrative embodiment, there is provided a method for setting a
rivet in a work
piece, the rivet having a rivet manufactured head and a shank having a shank
end, said method
having steps comprising: sensing when a rivet set tool of a rivet driver has
engaged the rivet
manufactured head or the shank end of the rivet and indicating that the rivet
set tool is ready;
sensing when a bucking bar has engaged the rivet manufactured head or the
shank end of the rivet
.. and indicating that the bucking bar is ready; driving the rivet by forcing
the shank against the
bucking bar with the rivet set tool to form a driven rivet head or by forcing
the rivet manufactured
head against the bucking bar with the rivet set tool to form a driven rivet
head; determining when
the height of the driven rivet head is substantially equal to a desired set
rivet head height; and
ceasing driving the rivet. In another embodiment, said sensing steps and/or
said determining step
.. comprises closing electrical circuits. In another embodiment, said
indicating steps comprise one or
more of activating a visual indicator, deactivating a visual indicator, and
continually and
sequentially activating and deactivating a visual indicator. In another
embodiment, said
determining step further comprises disabling the rivet driver. In another
embodiment, said
disabling comprises actuating a valve to decouple the rivet driver from a
power source. In another
embodiment, said driving step comprises forcing an anvil face against the
shank and
simultaneously pushing a plunger and a base against the work piece, thereby
causing the anvil face
to move toward the base as the driven rivet head is formed. In another
embodiment, one or more of
said indicating steps comprises a radio frequency communication. In another
embodiment, the
method further comprises monitoring contact between the bucking bar and the
rivet shank and
counting the number of hammer blows during the driving step. In another
embodiment, the method
further comprises upon said ceasing step, transmitting an end of riveting
cycle signal to disable the
rivet gun. In another embodiment, said forcing comprises urging the plunger
base against the work
piece to compress a resilient member when the anvil face is forced against the
shank. In another
embodiment, said determining step comprises sensing when the plunger is
displaced away from a
.. plane containing at least a portion of said anvil face a selected distance.
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In a further illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, the rivet having a rivet manufactured head and a shank having a shank
end, said system
comprising: means for sensing when a rivet set tool of a rivet driver has
engaged the rivet
manufactured head or the shank end of the rivet and indicating that the rivet
set tool is ready;
means for sensing when a bucking bar has engaged the rivet manufactured head
or the shank end of
the rivet and indicating that the bucking bar is ready; means for driving the
rivet by forcing the
shank against the bucking bar with the rivet set tool to form a driven rivet
head or means for
driving the rivet by forcing the rivet manufactured head against the bucking
bar with the rivet set
tool to form the driven rivet head; means for determining when the height of
the driven rivet head
is substantially equal to a desired set rivet head height; and means for
ceasing driving the rivet.
In another illustrative embodiment, there is provided a system for determining
when a rivet
gun set tool having a first anvil face contacts a rivet and when a bucking bar
having a second anvil
face contacts a rivet shank, said system comprising: means for determining
when the first anvil
face contacts the manufactured head or when the second anvil face contacts the
rivet that are
incorporated into the rivet gun set tool or into the bucking bar tool; and
means for informing an
operator when the rivet gun set tool contacts the rivet 5 or when the second
anvil face contacts the
rivet shank. In another embodiment, the system is also for setting a rivet in
a work piece, the rivet
having a rivet manufactured head and a rivet shank, said system further
comprising: a rivet gun
having a rivet set tool that is energized by a pressurized fluid that must
pass through a valve, said
valve having a first port through which said pressurized fluid enters said
valve and a second port
through which said pressurized fluid must pass to reach said rivet gun; an
augmented bucking bar
having a contact; a first source of electrical current that is disposed in a
first normally open
electrical circuit that also includes a first work piece, a first visual
indicator and said rivet set tool
connected in series, said first source of direct current being operative to
activate said first visual
indicator when said rivet set tool is placed in contact with said rivet
manufactured head; a second
source of electrical current that is disposed in a second normally open
electrical circuit that also
includes a second work piece, a second visual indicator and said augmented
bucking bar connected
in series, said second normally open electrical circuit also being connected
to a relay, said second
source of electrical current being operative to activate said second visual
indicator when said
augmented bucking bar is placed in contact with said rivet shank; a third
source of electrical
current that is disposed in a third normally open electrical circuit that also
includes said second
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work piece, said relay and said contact connected in series, said third source
of electrical current
being operative to actuate said relay when said contact is brought in contact
with said second work
piece during a riveting cycle; and a fourth source of electrical current that
is disposed in a fourth
normally open electrical circuit that also includes said relay and said valve,
said fourth source of
electrical current being operative to close said first port of said valve when
said relay is actuated.
In another illustrative embodiment, there is provided a method for setting a
rivet in a work
piece, with a rivet gun having a rivet set tool having a first anvil face and
a power source; and with
a bucking bar having a second anvil face; and with at least one circuit
subassembly having an
electrical power source and being capable of at least one of: monitoring,
indicating,
communicating, sequencing, and controlling a rivet driving process; the rivet
having a rivet
manufactured head and a shank having a shank end that is deformable into a
driven rivet head
when the rivet is set, said method comprising: using the rivet gun, the
bucking bar, and the at least
one circuit subassembly to set the rivet; sensing when a rivet gun operator
commences rivet setting
with the rivet gun having the rivet set tool and indicating to a bucking bar
operator that the rivet
gun operator is ready to commence riveting; sensing when the bucking bar
operator commences
rivet setting with the bucking bar and indicating to the rivet gun operator
that the bucking bar
operator is ready to commence riveting; and whereby when the commencement of a
rivet setting
cycle is sensed, communication between the rivet gun operator and the bucking
bar operator is
establish ed. In another embodiment, the method further comprises: driving the
rivet by forcing the
shank end against either the first anvil face or the second anvil face causing
the shank end to
deform; and sensing when the driven rivet head height is substantially equal
to a desired set rivet
head height and indicating to a rivet gun operator or a bucking bar operator
that the desired set rivet
head height has been achieved or ceasing driving the rivet when said driven
rivet head height is
substantially equal to the desired set rivet head height. In another
embodiment, the method further
comprises: adjusting a sensor actuating threshold positioned on the rivet set
tool or on the bucking
bar to match a desired rivet head height; actuating a valve with the circuit
subassembly to
operatively decouple the rivet gun from a power supply source and stop
riveting when the sensor
actuating threshold is detected; and whereby when the rivet is set, a desired
rivet head height
approximately matches a driven rivet head height and the rivet is set with
tolerance control. In
another embodiment, the method further comprises: sensing a rivet setting
stage; and enabling the
rivet gun during the rivet setting stage and otherwise disabling the rivet gun
by decoupling the rivet
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gun from a power source, thereby preventing damage to the rivet and/or the
work piece caused by
an incorrect tool operation. In another embodiment, the method further
comprises: sensing and
determining a rivet gun hammer cycle period or frequency; sensing
disengagement of the first anvil
face or of the second anvil face from a surface of the rivet surface during a
rivet deforming stage
.. and before sensing that a desired rivet head height has been achieved; and
disabling the rivet gun
by decoupling it from the power source, thereby preventing damage to the rivet
and the work piece
caused by an incorrect rivet driving operation. In another embodiment, the
method further
comprises: assessing a rivet deforming process and determining if the power
level to the rivet gun
should be increased or decreased to correspondingly increase or decrease a
rivet gun hammering
force; and communicating a recommended power level adjustment to an operator
or otherwise
automatically adjusting the power level, thereby controlling a rivet set
strength and a rivet set
tolerance. In another embodiment, the method further comprises: sending and or
receiving rivet
driving process information between a plurality of circuit subassemblies to
achieve at least one of:
controlling a rivet tool equipment during the sequence of steps of a rivet
setting cycle; indicating a
rivet driving stage to an operator; preventing damage to the rivet or to the
work piece; controlling a
plurality of rivet set tolerances; adjusting or recommending to an operator an
adjustment to a power
supply setting; recording a plurality of rivet set data; and repeating a
plurality communication
signals to avoid blocking of said communication signals by a work piece
material. In another
embodiment, the method further comprises providing a loaded plunger having
spindles feet on a
.. backriveting system or on a bucking bar system wherein said feet contact
the work piece
approximately during a rivet deforming stage; sensing and determining
approximate orthogonal
alignment between the work piece and either the backriveting system of the
rivet gun or the
bucking bar system; stopping a rivet deforming activity by decoupling the
rivet gun from its power
source when determination of the approximate orthogonal alignment is
approximately wrong or so
informing the bucking bar operator and/or the rivet gun operator of status of
the approximate
orthogonal alignment; and whereby aiding tool operators maintain approximate
orthogonal
alignment of the systems relative to the work piece and establishing a
capability to prevent
operators from forming misshapen rivets or damaging the work piece when a
rivet set tool or a
bucking bar is misaligned. In another embodiment, the method further
comprises: sensing when a
.. rivet gun operator approximately engages the rivet with the rivet gun
having the first anvil face to
first commence a rivet setting cycle and indicating to a bucking bar operator
that the rivet gun
operator is ready to commence riveting, or sensing when the bucking bar
operator approximately
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engages the rivet with the bucking bar having the second anvil face to
commence a second rivet
setting cycle and indicating to the rivet gun operator that the bucking bar
operator is ready to
commence riveting; first actuating a valve to couple a power supply to rivet
gun enabling rivet gun;
driving the rivet to cause the shank end of said rivet to deform; sensing when
the height of the
driven rivet head is substantially equal to a desired set rivet head height
and indicating to both the
bucking bar operator and the rivet gun operator 5 that the desired set rivet
head height has been
achieved, or ceasing driving the rivet when the height of the driven rivet
head is substantially equal
to the desired set rivet head height by second actuating solenoid valve to
decouple the power
supply from the rivet gun.
In another illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a shank having a shank
end that is
deformable into a driven rivet head having a driven rivet head height when the
rivet is set and said
driven rivet head height substantially matches a desired rivet head height,
said system comprising:
.. a bucking bar system or a rivet gun having a backriveting system, wherein
said bucking bar system
or said backriveting system are made entirely or in part of items selected
from the group consisting
of: a plunger, a load source, an electric power supply, a circuit subassembly,
a controller
subsystem, a sensor, an indicator, and a valve. In another embodiment, the
system further
comprises: means for sensing when a rivet gun operator commences rivet setting
with said rivet
gun having a backriveting system and indicating to a bucking bar operator that
the rivet gun
operator is ready to commence riveting; or means for sensing when the bucking
bar operator
commences rivet setting with the bucking bar system and indicating to the
rivet gun operator that
the bucking bar operator is ready to commence riveting.
In a further illustrative embodiment, there is provided a system for setting a
rivet in a work
piece, said rivet having a rivet manufactured head and a shank having a shank
end that is
deformable into a driven rivet head having a driven rivet head height, said
system comprising: one
of the group consisting of: (a) a rivet gun having a power source and a
backriveting system, said
backriveting system having a first circuit subassembly being powered by a
power source, and a
bucking bar operator ready indicator and/or a desired rivet height sensor; or
(b) a bucking bar
system, said bucking bar system having a bucking bar and a rivet gun operator
ready indicator
and/or a desired rivet height sensor. In another embodiment, the system
further comprises means
for sensing when the bucking bar operator commences rivet setting with said
bucking bar system
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and indicating to the rivet gun operator that the 30 bucking bar operator is
ready to commence
riveting. In another embodiment, said backriveting system further comprises
one or more parts
selected from a group consisting of: a first sensor that is capable of
detecting when said driven rivet
head height substantially matches a desired set rivet head height; and a
second sensor that is
capable of detecting when a set tool system operator first engages or
otherwise contacts the rivet
manufactured head or the shank end of the rivet. In another embodiment, said
bucking bar system
further comprises one or more sensors selected from a group consisting of: a
first sensor that is
capable of detecting when said driven rivet head height substantially matches
a desired set rivet
head height; and a second sensor that is capable of detecting when the bucking
bar operator first
engages or otherwise contacts the rivet manufactured head or the shank end of
the rivet. In another
embodiment, said bucking bar system further comprises one or more parts
selected from a group
consisting of: a first sensor that is capable of detecting when the driven
rivet head height
substantially matches a desired set rivet head height; a second circuit
subassembly being powered
by another power source; a second sensor that is capable of detecting when a
bucking bar system
first engages or otherwise contacts the rivet manufactured head or the shank
end of the rivet. In
another embodiment, said backriveting system or said bucking bar comprises a
microprocessor for
acquiring a plurality of sensor array subsystem data, said microprocessor
having a power
subsystem and said microprocessor being operative to process said plurality of
sensor array
subsystem data to determine at least one of: when a rivet gun contacts a
surface of the rivet and to
further determine a rivet driving stage and then to operate at least one of
indicator to indicate said
rivet driving stage to the rivet gun operator or to the bucking bar operator;
when the rivet gun or
the bucking bar incorrectly disengages from the surface of the rivet during a
rivet deforming
activity and before the driven rivet head height matches a desired rivet head
height and then to stop
the rivet gun; and when the driven rivet head becomes deformed to
approximately match the
desired rivet head height and then to stop the rivet gun. In another
embodiment, the system further
comprises: means for driving the rivet by forcing the shank end either against
an anvil face of said
backriveting system or against an anvil face of said bucking bar system and
causing the shank end
to deform into the driven rivet head; means for sensing when the driven rivet
head is substantially
equal to a desired set rivet head height; and means for ceasing
driving the rivet when the driven rivet head height is substantially equal to
the desired set rivet
head height. In another embodiment, the system further comprises: means for
adjusting a sensor
having a sensor actuating threshold located on the backriveting system or on
the bucking bar
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system to match an approximate measurement of a desired rivet head height; and
a second circuit
subassembly means to actuate a valve to operatively decouple the rivet gun
from a power supply
source and stop riveting when the sensor actuating threshold is detected. In
another embodiment,
the system further comprises: means for sensing a rivet deforming stage; and
means for enabling
the rivet gun during the rivet deforming stage while otherwise disabling the
rivet gun by
decoupling it from its power source. In another embodiment, the system further
comprises: means
for sensing and determining a rivet gun impact period or frequency; means for
sensing
disengagement of an anvil face from a rivet surface during a rivet deforming
stage and before
sensing that a desired rivet head height has been achieved thereby determining
an incorrect
operator action; and means for disabling the rivet gun by decoupling it from
its power source. In
another embodiment, the system further comprises: means for assessing a rivet
deforming process
and determining if the power level to the rivet gun should be increased or
decreased to
correspondingly increase or decrease the hammering force of the rivet gun; and
means for
communicating a recommended power level to the rivet gun operator or
automatically adjusting
the power level. In another embodiment, the system further comprises: means
for sending and or
receiving rivet driving process information among a plurality of circuits to
achieve at least one of: a
determination of a rivet driving stage; an indication of a rivet driving
stage; prevention of damage
to said rivet or said work piece; control of rivet set tolerances; adjusting
or recommending an
adjustment to power level setting; recording rivet set data; and repeating
communication signals.
In yet another illustrative embodiment there is provided a set rivet produced
in accordance
with a method for fastening a rivet having a shank and a shank end in a work
piece having a work
surface with a system comprising a rivet driver, a controller that is
operative to enable and disable
said rivet driver, a microprocessor that is operative to control said
controller, a plunger having a
contact point, a load source that is operative to urge said contact point to
maintain contact with the
work surface, an anvil having an anvil face, and a first sensor that is
operative to sense the distance
between the work surface and the anvil face, said method comprising: placing
the plunger on the
work surface; advancing the plunger to activate the load source until the
anvil face contacts the
shank end; driving the rivet with the rivet driver; with the first sensor,
sensing the distance between
the work surface and the anvil face and generating an input signal; and with
the microprocessor,
receiving said input signal from the first sensor, determining when said
distance is approximately
equal to a desired rivet head height, and then actuating the controller,
thereby disabling the rivet
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driver. In another illustrative embodiment, there is provided a plurality of
set rivets, each of said set
rivets being produced in accordance with a method for fastening a rivet having
a shank and a shank
end in a work piece having a work surface with a system comprising a rivet
driver, a controller that
is operative to enable and disable the rivet driver, a microprocessor that is
operative to control the
controller, a plunger having a contact point, a load source that is operative
to urge the contact point
to maintain contact with the work surface, an anvil having an anvil face, a
first sensor that is
operative to sense a distance between the work surface and the anvil face, and
a second sensor, said
method comprising: placing the plunger on the work surface and applying a
force to the plunger
that is operative to load the load source until the anvil face contacts the
shank end; driving the rivet
.. with the rivet driver; with the first sensor, sensing the distance between
the work surface and the
anvil face and generating an input signal; with the second sensor, generating
a second signal when
the anvil face first contacts the shank end; with the microprocessor,
receiving the first and second
input signals from the first sensor and the second sensor, determining a rivet
size, and determining
when said distance is approximately equal to a desired rivet head height, and
then actuating the
controller, thereby disabling the rivet driver. In another embodiment, the
system further comprises
a second sensor and said method further comprises: with the second sensor,
generating a second
signal when the anvil face first contacts the shank end; with the
microprocessor, receiving said
second input signal and generating a second output signal that indicates to a
user that said anvil
face is in first contact with the shank end.
In another illustrative embodiment, there is provided a non-transitory
computer-readable
medium including computer-executable instructions which, when loaded onto a
computer performs
a method comprising: during said rivet driving stage, monitoring the rivet to
determine when a
measured rivet set height is approximately equal to a desired rivet head
height; and when said
measured rivet set height is approximately equal to the desired rivet head
height, ceasing riveting,
thereby terminating the rivet driving stage. In another embodiment, the method
further comprises:
monitoring the rivet to determine if the anvil face becomes decoupled from the
rivet shank end; and
if said anvil face becomes decoupled from the rivet shank end, ceasing
riveting, and indicating an
error condition to an operator.
In another illustrative embodiment, there is provided a non-transitory
computer-readable
medium including computer-executable instructions which, when loaded onto a
computer performs
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a method comprising: detecting when a first anvil face first contacts a rivet
manufactured head and
indicating that the first anvil face operator is ready; detecting when a
second anvil face first
contacts said rivet shank end, storing a protruding length of the rivet shank
in a memory; and
determining and storing in the memory a desired rivet head height, and
indicating that the second
anvil face operator is ready; optionally enabling a rivet driver by actuating
a controller, thereby
initiating a rivet driving stage; during the rivet driving stage, monitoring
the rivet to determine
when a measured rivet set height is approximately equal to said desired rivet
head height; and when
the measured rivet set height is approximately equal to said desired rivet
head height, ceasing
riveting, thereby terminating the rivet driving stage. In another embodiment,
said method further
comprises: during the rivet driving stage, monitoring the rivet to determine
if the first anvil face
becomes decoupled from the rivet manufactured head; during the rivet driving
stage, monitoring
the rivet to determine if the second anvil face becomes decoupled from rivet
shank end; if the first
anvil face becomes decoupled from the rivet manufactured head or the second
anvil face becomes
decoupled from the rivet shank end, ceasing riveting, and indicating an error.
condition to an
operator.
In one embodiment, there is provided a system for fastening a rivet in a
workpiece with a
rivet driver, the workpiece having a work surface, the rivet having a
manufactured head, a shank,
and a shank end, the shank and shank end nominally projecting from the work
surface. The system
includes an anvil having an anvil face, and a plunger slidably engaged with
said anvil. Said
plunger has a plunger distal end, the plunger distal end nominally extending
beyond said anvil face.
The system further includes: a load source that is operative to nominally urge
said plunger distal
end forward relative to said anvil face to maintain contact with the work
surface; a sensor that is
operative to sense a distance between the plunger distal end and the anvil
face and produce a first
input signal related to said distance; and a control subsystem comprising a
controller. The control
subsystem is operative to enable and disable the rivet driver, and receive the
first input signal from
the first sensor and send an output signal to the controller, and disable the
rivet driver when said
distance is substantially equal to a desired rivet head height.
The system may include: a first sensor configuration consisting of said sensor
that is
operative to produce said first input signal when said anvil face first
contacts the shank end; or a
second sensor configuration consisting of a second sensor that is first
operative to produce a second
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input signal when said anvil face first contacts the shank end and a further
sensor that is second
operative to produce a further input signal when said anvil face first
contacts the shank end, or a
third sensor configuration consisting of a third sensor that is operative to
produce a third input
signal when said anvil face contacts the shank end. The first, second or third
sensor configurations
may be each operative to sense said distance when said anvil face first
contacts said shank end, and
produces a specific input signal related to said distance. The specific input
signal from any sensor
configuration of said first, second or third sensor configurations may be
representative of a shank
length nominally projecting from said work surface upon said first contact.
The control subsystem
may receive said specific input signal from said any sensor configuration, may
store said distance,
.. may determine said desired rivet head height, and may store said desired
rivet head height.
The system may include a fourth sensor having a plurality of spindles feet at
said distal end
of said plunger, the fourth sensor operative to produce a fourth input signal
when the spindles feet
are substantially in contact with said work surface. The control subsystem may
be operative to: at
least one of determine if the anvil face is substantially parallel to said
work surface and determine
if said spindles feet are substantially in contact with said work surface; and
disable the rivet driver
when said anvil face is not substantially parallel to said work surface or
when said spindles feet are
not substantially in contact with said work surface.
The system may include a set tool that is coupled to the rivet driver at a
first end and is
operative to impact the manufactured head at a second end. The system may
further include a fifth
sensor that is operative to produce a fifth input signal when driving the
rivet and said second end of
said set tool is substantially in communication with said manufactured head.
The control
subsystem may be operative to: evaluate said fifth input signal from said
fifth sensor to determine
when said second end of the set tool is not substantially in communication
with the manufactured
head; and disable the rivet driver when said second end of said set tool is
not substantially in
communication with the manufactured head.
The system may include a first indicator that is operative to indicate when
said second end
of said set tool makes first contact with said manufactured head. The control
system may receive
the fifth input signal from said fifth sensor and the control subsystem may be
operative to toggle
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said first indicator that indicates that said second end of said set tool is
in contact with said
manufactured head and representative that a rivet gun operator is in "ready"
condition.
The system may include a second indicator that is operative to indicate when
said anvil
face makes said first contact with said shank end. The control subsystem may
receive the third
input signal from the third sensor and the control subsystem may be operative
to toggle said second
indicator that indicates that said anvil face is in contact with said shank
end and representative that
a bucking bar operator is in "ready'' condition.
The system may include a third indicator that is operative to indicate when
said spindles
feet are in contact with said work surface. The control subsystem may receive
said second input
signal from said second sensor and the control subsystem may be operative to:
determine, when
driving the rivet, if said spindles feet are substantially in contact with
said work surface; and toggle
the third indicator that indicates said spindles feet are not substantially in
contact with said work
surface.
The control subsystem may receive said first indicator or an input signal from
a second
sensor. The control subsystem may be operative to: determine if said second
end of said set tool is
substantially in communication with said manufactured head; determine a damage
event condition;
and operate said controller to disable said rivet driver when said damage
event condition is
determined.
The control subsystem may receive said second indicator or said second input
signal from
said second sensor. The control subsystem may be operative to: determine if
said anvil is
substantially in communication with said shank end; determine a damage event
condition; and
operate said controller to disable said rivet driver when said damage event
condition is determined.
The control subsystem may receive the said first input signal from said
sensor, or may
receive said second input signal from said second sensor and then receive said
input signal from
said sensor, or may receive said second input signal from said second sensor
and then receive said
further input signal from said further sensor, or may receive said third input
signal from said third
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sensor. The control subsystem may be operative to determine and store the
desired rivet head
height.
The control subsystem may determine the desired rivet head height, may be
operative to
analyze the first input signal from said sensor to assess plastic deformation
of a rivet shank and
may be operative to disable the rivet driver when said distance is
substantially equal to said desired
rivet head height.
The system may include a user input device that is operative to receive input
from a user.
The control subsystem may be operative to receive said input from said user
and the first input
signal from said first sensor when said plunger distal end is a known distance
from said anvil face,
to calibrate the distance between the plunger distal end and the anvil face.
The first sensor may have a switching threshold and may be operative to
produce a digital
signal, whereby a physical feature on the plunger actuates the switching
threshold of said first
sensor when the plunger is axially displaced a distance representative of the
desired rivet head
height.
The system may include a sixth sensor that is operative to sense an impact
magnitude from
a rivet diver blow, and produce a sixth input signal when the rivet driver
produces an impact on the
rivet. The control subsystem may receive said sixth input signal and may be
operative to determine
and store at least one of: a tally of said impacts required to set rivet to
said desired rivet head height
and the impact frequency of a rivet driver.
The control subsystem may include at least one control subsystem. The system
may further
include a data base operating on a central computer, said central computer
being operative to
receive a plurality of data sets from the at least one control subsystem and
store said data sets in
said data base. The data sets may include data consisting of at least one of a
protruding rivet shank
length, the desired rivet head height, a rivet set head height, and a count of
impacts from the rivet
driver, required to form said rivet set head height.
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The system may include said controller. Said controller may be operative to
enable and
disable said rivet driver, and said controller may comprise an input coupled
to a power source and
an output coupled to the rivet driver. The control subsystem may disable the
rivet driver by
actuating said controller to decouple the power source from the rivet driver,
or may enable said
rivet driver by actuating the controller to couple the power source to the
rivet driver.
The control subsystem may include a plurality of control subsystems. The
system may
further include a memory, an addressable communication capability between at
least two control
subsystems, and a central computer having central memory. Said central
computer may be in
communication with or comprised of at least one of the plurality of control
subsystems. The
plurality of control subsystems may be operable to transfer a data set of
riveting information to said
central memory, and said central memory may store said data set.
The control subsystem may include at least two control subsystems. The system
may
further include first and second radios coupled between the at least two
control subsystems and
operative to send and receive data between said at least two control
subsystems.
Further aspects of the disclosed embodiments will become apparent from
consideration of
the drawings and the ensuing description of the disclosed embodiments. A
person skilled in the art
will realize that other embodiments are possible and that the details of the
disclosed embodiments
can be modified in a number of respects, all without departing from the
concept. Thus, the
following drawings and description are to be regarded as illustrative in
nature and not restrictive.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The features of the disclosed embodiments will be better understood by
reference to the
accompanying drawings which illustrate presently disclosed embodiments. In the
drawings:
Figs. lA through ID present perspective views of conventional bucking bars
used in the
prior art.
Figs. 2A and 2B present elevation views of two types of prior art rivet
fasteners.
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Fig. 3 is an elevation view illustrating properly set rivets of the types
shown in Figs. 2A and
2B.
Fig. 4A is an elevation view of an improperly set prior art rivet of the type
shown in Fig. 2A.
Fig. 4B is an elevation view of an improperly set prior art rivet of the type
shown in Fig. 2A.
Fig. 4C is an elevation view of an improperly set prior art rivet of the type
shown in Fig. 2A.
Fig. 4D is an elevation view of an improperly set prior art rivet of the type
shown in Fig. 2A.
Fig. 4E is an elevation view of an improperly set prior art rivet of the type
shown in Fig. 2A.
Fig. 4F is an elevation view of an improperly set prior art rivet of the type
shown in Fig. 2A.
Fig. 5A is a schematic diagram of one disclosed embodiment.
Fig. 5B is an elevation view of an aspect of the disclosed embodiment
illustrated in Fig. 5A
Fig. 6A is an exploded perspective view of the major mechanical components of
a bucking
bar in accordance with another disclosed embodiment.
Fig. 6B is an assembled perspective view of the bucking bar presented in Fig.
6A.
Fig. 7A is a partial cross-sectional view of the bucking bar presented in Fig.
6B (for purposes
of clarity, only selected components are presented).
Fig. 7B is a detailed cross-sectional view of the bucking bar presented in
Fig. 6B (including
parts shown in Fig. 7A).
Fig. 8 is a schematic diagram of another disclosed embodiment, exhibiting
general
components and their relationships.
Fig. 9 is a perspective view of an alternate embodiment of the bucking bar.
Fig. 10 is a schematic block diagram of a microprocessor in accordance with
another
disclosed embodiment.
Fig. 11 is a schematic block diagram of a control system in accordance with a
disclosed
embodiment comprising the microprocessor illustrated in Fig. 10 interconnected
with
microprocessor peripherals.
Fig. 12 is a schematic process flow diagram for a microprocessor program or
software
listing in accordance with another disclosed embodiment.
Fig. 13 is a cross-sectional view of yet another alternate embodiment of a
bucking bar.
FIG. 14 is a cross-sectional view of yet another alternate embodiment by
applying the
electromechanical components previously illustrated in Figs 7A and 7B.
Fig. 15 is a cross-sectional view of still another alternate embodiment of the
bucking bar
illustrated in Figs. 7A and 7B.
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Fig. 16 is a perspective view of still another embodiment of the bucking bar
illustrated in
Figs. 7A and 7B and serves to illustrate electrical contact points on the
spindles feet.
Fig. 17 is a schematic block diagram of yet another simplified embodiment of
rivet system
illustrated in Fig. 5.
Fig. 18 is a simplified schematic block diagram of yet another simplified
embodiment of
rivet system.
Fig. 19 is schematic flow diagram for software instructions in accordance with
the simplified
embodiment illustrated in Fig. 18.
Fig. 20 is a schematic block diagram that illustrates the general
relationships among the
components of an alternate radio frequency embodiment of the invention.
Figs. 21A and 21B are schematic diagrams that illustrate another disclosed
embodiment.
Figs. 22 and 23 are screen shots of an oscilloscope monitoring the operation
of another
disclosed embodiment.
Fig. 24 is a partial cross-sectional view of still another alternate
embodiment depicting
another backriveting approach similar to Fig. 14 but also applying the
teachings previously
illustrated in Figs. 7A and 7B.
Fig. 25 is a partial cross-sectional view of still another alternate
embodiment.
Figs. 26 and 27 are partial cross-sectional views of still another disclosed
embodiment
depicting means for tool alignment and tool contact and illustrating alternate
sensing approaches
and sensing technology applications that may be applied to teachings
previously illustrated in Figs.
7A, 7B, 13, 14, 15, 16, and 24.
Fig. 28 is a simplified schematic block diagram of yet another simplified
embodiment of
rivet system that may be applied to teachings previously illustrated in Figs
5A, 7A, 7B, 8, 9, 13, 14,
15, 16, 17, 18, 20, 21A, 2113, 24, 25, and 26.
Figs. 29A and 29B are a schematic flow diagram for software instructions in
accordance with
another disclosed embodiment. Fig. 29B is a continuation of Fig. 29A.
The following reference numerals are used to indicate the parts and
environment of the
invention on the drawings:
52 first common bucking bar
52' augmented bucking bar
54 second common bucking bar
56 third common bucking bar
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58 fourth common bucking bar
62 manufactured common rivet head, manufactured universal rivet
head, manufactured
rivet head,
20 rivet head
63 semicircular cut, mar, smiley damage to rivet manufactured head
63' semicircular cut, mar, dent, smiley damage to work piece
64 counter-sunk rivet head, flush rivet head, manufactured rivet
head, rive head
66 rivet manufactured head, manufactured head
68 rivet shank
70 end of rivet shank, rivet shank end
72 first work piece
73 second work piece
74 first facing surface, work piece sheathing surface nearest
rivet manufactured head,
first work surface
76 second facing surface, work piece sheathing surface nearest rivet shank
end, second
work surface
78 work thickness
80 distance
82 rivet head width
84 desired set rivet head height
84a low side rivet head height
84b high side rivet head height
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84c overdriven rivet head height
84d underdriven rivet head height
86 rivet head
96 air gap
98 bulge
100 rivet fastening system
102 pneumatic rivet gun, rivet gun, rivet driver
104 rivet set tool, set tool
106 positive low voltage DC power supply, power supply source
108 first conducting wire
110 air hose
112 electro-mechanical solenoid valve, solenoid valve, valve
114 first LED indicator light
116 second conducting wire
118 ground
124 second LED indicator light
126 third conducting wire
128 sensor pad
130 electrically-conductive contacting surface, contact
134 fourth conducting wire
136 third LED indicator light
138 fourth LED indicator light
212 rivet gun operator control circuit board, first circuit board
212' bucker control circuit board, second circuit board
212" RF repeater circuit board, third circuit board
212" data acquisition system, fourth circuit board
212" solenoid control circuit board, fifth circuit board
212" air regulator control circuit board, sixth circuit board
214 mounted LED indicator light, first indicator light
216 mounted LED indicator light bar
218 user selectable position switches
220 first conducting lead wire
226 second conducting lead wire
232 first multi-conductor cable
236 second multi-conductor cable
237 third multi-conductor cable
238 bucking bar
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240 bucking bar indicator LED light, second indicator light
240" second indicating LED
250 cap bolt fastener
252 micro-adjustable jackscrew, jackscrew
254 cap
256 conducting post
257 longitudinal axis
258 e-spring clip, clip
260 housing
262 housing bolt fasteners
264 traveling nut
266 load source, compression spring
268 plunger
270 hammer
300 anvil face
302 interior cylinder stem, cylinder stem
304 distal shoulder
306 plunger stem
308 plunger shoulder
310 proximal shoulder
312 spindles feet, lip
312' first contact point
312" second contact point
313" third contact point
314 first distance, gap height, distance between the anvil face and the
spindles feet, distance between
the work surface and anvil face
316 second distance, translated first distance 314
318 proximal surface
320 housing and plunger surfaces
322 hammer and plunger surfaces
323 cylinder stem and plunger stem surfaces
325 hammer stem, hammer shaft
326 hammer stem and plunger surfaces
327 hammer base
350 microswitch, switch
352 switch lever arm
354 jack-plug assembly
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358 momentary push-button switch and indicator LED light assembly
360 first internal wire
362 third internal wires
364 second internal wires
366 housing and traveling nut surfaces
368 plunger stem and traveling nut surfaces
371 first switch chatter signature
371' second switch chatter signature
373 first contact bounce signature
373' second contact bounce signature
375 first falling edge hammer signature
375' second hammer signature
377 time interval
500 digital logic device, microcomputer, microcontroller,
microprocessor, computer, controller,
control subsystem
502 processor(s)
504 random access memory, RAM, memory
506 read only memory, ROM
508 bus
510 storage device
512 input/output device(s)
514 sensor interface
520 bucking bar control system, rivet set tool control system,
control system
522 computer, microcomputer
524 power subsystem
526 sensor array subsystem
528 control and communication subsystem
530 rechargeable battery, battery
532 power regulator, regulator
534 external power supply, power supply
540 pneumatic solenoid, pneumatic solenoid valve, solenoid valve,
valve
542 communication indicators
544 communication port
546 graphic user interface
548 keypad, interface
550 initialize step
552 detect "AG Ready" step

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554 gun ready conditional step
556 turn LEDs on step
558 detect "BB Ready" step
560 bucker ready conditional step
562 initiate riveting step
564 detect start rivet step
566 rivet start conditional step
568 start timer/count impacts step
570 detect height threshold conditional step
572 end riveting cycle step
574 first interrupt service request step
576 second interrupt service request step
578 forced recalibration step
580 conduct calibration, calibration mode
582 stop rivet gun IRQ from "detect if user disengaged work during driving
cycle" in block 568
600 cap screw
602 access port
605 slot type photointen-upter switch
606 strain relief device
611 housing shoulder
640 set tool assembly
650 external collar
652 external setscrew
654 internal collar
656 internal setscrew
702 threaded traveling nut
704 key, axially-positioned tab, tab
706 switch housing collar
708 first embedded switch
710 second embedded switch
712 shoulder of collar
713 shoulder of housing
802 first battery
804 second battery
806 third battery
808 relay
810 fourth battery
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902 NPN type transistor
904 relay, field effect transistor, transistor, solenoid driver,
valve driver, driver, valve controller,
controller
906 user activated switch
908 calibration mode LED
950 start step
952 initialize system step
954 main program step
956 rivet gun operator ready step, bucker ready block
958 bucker ready step, bucker ready block
960 error detection step, fault management step, error detection
block
962 calibration step, calibration block
964 system reset step, system reset block
990 pressure regulator, flow regulator, air regulator
992 radio frequency signals
994 management computer, central computer
1002 spring coupling recess, recess
1004 first raised cylinder diameter
1006 second raised cylinder diameter
1008 spring clip recess, recess
1010 internal spring clip, clip
1012 hole
1014 spiral roll pin, roll pin, pin
1016 pin slots, slots
1018 lid
1020 sub-assembly circuit board
1022 multi-conductor jack plug, plug
1023 spring loaded electrical contacting pin
1024 light source, LED, lamp, user indicator, indicator
1026 hole in lid, hole
1027 light from LED light source, light
1030 alternative set tool assembly
1032 alternative housing
1034 LED indicator light, light
1040 master circuit board, circuit board
1042 slave circuit board, circuit board subassembly, circuit board
1044 alternating to direct current power converter and supply,
power supply
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1046 2-conductor power port jack plug, power jack plug
1048 direct current supply voltage regulator, voltage regulator
1050 constant current supply regulator, current regulator
1054 controller block
1056 LED control block
1058 signal control block
1060 contact sensor block
1062 loop circuit sensor block
1063 indicator block, user communication for tool alignment aid
1064 momentary pushbutton microprocessor mode selection input device,
pushbutton, user interface
1066 first electrical conductive attachment mechanism, first
alligator clip
1068 second electrical conductive attachment mechanism, second
alligator clip
1100 alternate set tool
1104 first spring electrical contact, commutation lever,
commutator
1106 first electrical conducting pin
1108 second electrical conducting pin
1120 detector, sensor
1121 target detected by sensor, detected target, target
1150 firmware schematic drawing, schematic drawing
1152 power supply block, power conditioning, voltage and current
regulators, power supply
1154 valve control block, control block
1156 LED illumination and communication control circuit, light
control circuit
1158 power supply to spindle feet control, first loop circuit
formation, signal output
1160 contact detection of spindles feet or anvil face, second loop
circuit formation, contact detection
DETAILED DESCRIPTION OF THE INVENTION
The following description of the preferred embodiments of the invention is
merely exemplary in nature and
is in no way intended to limit the invention, its application, or uses. In
preferred embodiments, the rivet fastening
system disclosed herein is configured to control the rivet setting process and
the resultant rivet set.
Referring to Figs. IA through 1 D, prior art examples of common conventional
bucking bars are illustrated.
Conventional bucking bars are used to back up rivets during the fastening
process and comprise a metal mass
typically having a hardened material and a polished anvil face for impacting
the rivets. Conventional bars come in
numerous bar shapes, illustrated here by first common bucking bar 52, second
common bucking bar 54, third
common bucking bar 56 and fourth common bucking bar 58.
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Referring to Figs. 2A and 2B, examples of two typical prior art solid-core
rivets are presented. Both rivets
have manufactured heads 66, a rivet shank 68 and a rivet shank end 70. Fig. 2A
depicts a first type of said solid core
rivet having a dome shaped, common or universal rivet head 62. Fig. 2B depicts
a second type of said solid core
rivet having a counter-sunk or flush rivet head 64.
Referring to Fig. 3, examples of properly set prior art rivets are
illustrated. The rivets are used to fasten a
plurality of work pieces 72, 73 having combined work thickness 78 together.
Manufactured head 66 secures first
work piece 72 having first facing surface 74 while the driven rivet head 86
secures second work piece 73 having
second facing surface 76. Facing surfaces 74 and 76 are also work surfaces.
Typically, when undriven, rivet shank
68 initially protrudes beyond surface 76 a distance 80 of about I 'A times
work thickness 78. When set, rivet head
86 typically has a rivet head width 82 of about l',12 times the diameter of
rivet shank 68 and has a desired set rivet
head height 84 of about 'A of the diameter of rivet shank 68. Thus, when
properly sizing rivets to work thickness 78,
typically a rivet width 82 is a directly proportional function of rivet height
84 and visa versa. Rivet setting
specifications are further outlined in United States of America Military
Specification MIL-R-471 96A (MD.
Preferred embodiments of this invention provide configurations to achieve
measurement of the rivet head height in
real-time or near real time using preferred sensing technologies coupled with
the teachings (presented later) best
suited for this measurement. However, a person having ordinary skill in the
art would understand that should other
sensing technologies be developed or identified to measure rivet head width 82
in real-time or near real time, these
sensors could be incorporated into this invention without changing the intent
or concept of this invention. It is also
realized that other sensing technologies for measurement of the rivet head
height in real-time or near real time may
be developed or may be identified to further improve this invention.
Incorporation of such sensors are also
considered not to alter the intent or concept of this invention.
Referring to Fig. 4A, an illustration of an improperly set prior art universal
rivet is presented. Set low side
rivet head height 84a is less than minimum allowed height tolerance and/or set
high side rivet head height 84b is
greater than maximum allowed height tolerance. This illustration depicts a
misshapen rivet head resulting from tool
misalignment (by not holding the bucking bar orthogonal to the work surface).
Referring to Fig. 4B, an illustration of an improperly set prior art universal
rivet is presented. Set
overdriven rivet head height 84c is less than minimum allowed height tolerance
and/or set underdriven rivet head
height 84d is greater than maximum allowed height tolerance. This illustration
depicts a misshaped rivet head
resulting from the anvil face slipping off the rivet head during the rivet
fastening process.
Referring to Fig. 4C, an illustration of another improperly set prior art
universal rivet presented. In this
instance, set rivet head 86 is not centered on the longitudinal axis of rivet
shank 68. This set rivet shape results from
side-loads being applied to the rivet during the rivet driving stage and such
an improperly set rivet does not
adequately secure the work pieces together.
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Referring to Fig. 4D, an illustration of another improperly set prior art
universal rivet is presented. In this
instance, rivet 62 is set in a manner that allows a first type of air gap 96
to be formed between work pieces 72 and
73. Again, this results in a set rivet that does not adequately secure the
work pieces together.
Referring to Fig. 4E, an illustration of another improperly set prior art
universal rivet is presented. In this
instance, rivet 62 is set in a manner that allows a second type of air gap 96
to be formed between work pieces 72 and
73. This also results in a set rivet that does not adequately secure the work
pieces together. Furthermore, in this
instance, rivet shank 68 expands during the rivet setting process forming
bulge 98, which prevents the work pieces
from coming together flush and renders the rivet difficult to remove for
rework. The situations depicted in Figs. 4D
and 4E show improperly set rivets resulting from the work pieces not being
adequately pressed together during the
riveting process. Figs. 4A ¨ 4E illustrate out of tolerance set rivets that do
not adequately secure the work pieces
together and require removal and rework resulting in extensive lost labor time
and potential damage to the work
surfaces or subsurfaces.
Referring to Fig. 4F, an illustration of another improperly set prior art
universal rivet is presented. This
type of rivet is commonly driven using use a concave or cup-shaped anvil faced
set tool that matches said rivet head
62 shape. If a rivet gun impact event occurs when the set tool anvil face is
improperly positioned or aligned over
said rivet head 62, a semicircular cut, mar, or indentation commonly termed a
"smile" or a "smiley" can result as
another instance of an improperly set rivet. Fig. 4F shows damage to said
rivet head 62 illustrated by smiley 63 and
shows damage to work piece sheathing surface 74 illustrated by smiley damage
63'. Smiley damage requires
rework.
Referring to Figs. 5A and 5B, a simplified embodiment of the invention is
illustrated to simplify and teach
the invention. In this embodiment, rivet fastening system 100 comprises
pneumatic rivet gun 102 equipped with
rivet set tool 104. Rivet gun 102 may also be a rivet driver and a rivet
driver can also be any device that departs
energy to upset a rivet; not all rivet drivers are necessarily rivet guns. Set
tool 104 is preferably connected to
positive low voltage direct current (DC) power supply 106 by first conducting
wire 108. Rivet gun 102 is preferably
connected to an air reservoir (not shown) via air hose 110 with electro-
mechanical solenoid valve 112 being located
in-line with (in series with) air hose 110 between rivet gun 102 and the air
reservoir.
In this embodiment, second conducting wire 116 is coupled to work piece 73
that is connected in series
with first LED indicator light 114 to ground 118. Thus, when set tool 104
contacts rivet manufactured head 66
and/or work piece 72 or 73, a first loop circuit (forming a second sensor) is
closed from power supply source 106
through rivet manufactured head 66 and/or work piece 72 or 73 and second
conducting wire 116 to illuminate first
LED indicator light 114 and thereby indicate to the bucker (bucker bar
operator) that the rivet gun operator is
"ready" to begin the rivet cycle.

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In this embodiment, third conducting wire 126 is coupled to first common
bucking bar 52 which is
connected in series with second LED indicator light 124 to ground 118. Thus,
when common bucking bar 52
contacts rivet shank end 70, a second loop circuit (forming another second
sensor) is closed from power supply
source 106, first wire 108, through set tool 104 and rivet 62 to common
bucking bar 52 and third conducting wire
126 to illuminate second LED indicator light 124 to indicate to the rivet gun
operator that the bucker is also "ready"
to begin the rivet cycle.
Finally, referring to Fig. 5B, in this embodiment,-sensor pad 128 is
adhesively affixed to second facing
surface 76 adjacent to rivet shank 68. Sensor pad 128 is preferably comprised
of an adhesive pad (not shown) on a
first side and an electrically-conductive contacting surface 130 on a second
(opposite) side which is coupled to
fourth conducting wire 134. Sensor pad 128 is preferably comprised of a
compressible material such as a memory
foam that returns to its original height after compression force(s) are
removed. Sensor pad 128 preferably has a
height (measured between the described adhesive surface and conductive
contacting surface 130) that matches
desired set rivet head height 84.
Again referring to Fig. 5A, fourth conducting wire 134 is coupled in series to
third LED light 136 and
fourth LED light 138 and solenoid valve 112 between contacting surface 130 and
ground 118. Thus, when bucking
bar 52 contacts sensor pad 128 contacting surface 130 (this occurs when the
driven rivet head 86 achieves desired
set height 84), a third loop circuit (forming a first sensor) is closed from
source 106, first wire 108, through set tool
104, rivet 62, bucking bar 52, contacting surface 130 to illuminate third LED
indicator light 136 and fourth LED
indicator light 138 and close solenoid valve 112 to indicate to both operators
that the rivet setting cycle is at an end.
Solenoid valve 112 closes, disabling rivet gun 102 when rivet 62 has been set,
thereby automatically stopping the
riveting process.
Referring to Fig. 6A, an exploded view of a preferred embodiment of bucking
bar 238 is presented. In this
embodiment, bucking bar 238 is comprised of cap bolt fastener 250, micro-
adjustable jack screw 252, cap 254,
conducting post 256, e-spring clip 258, housing 260, housing bolt fasteners
262, traveling nut 264, load source or
compression spring 266, plunger 268 and hammer 270. During assembly of bucking
bar 238, jackscrew 252 is
affixed to cap 254 by means of e-spring clip 258 (jack screw 252 is not
threadedly engaged with cap 254 or with clip
258). Then, housing bolt fasteners 262 affix housing 260 to cap 254. Next,
traveling nut 264 is threadedly engaged
with jackscrew 252 forming a micro-adjustable traveling-nut-positioning
jackscrew assembly. Next, compression
spring 266 and plunger 268 are installed, guided by the shaft of hammer 270.
The assembly process is completed by
affixing the end of the shaft of hammer 270 to cap 254 with cap bolt fastener
250. Cap bolt fastener 250 is
threadedly engaged with the end of the shaft of hammer 270. FIG. 6B shows a
perspective view of assembled
bucking bar 238.
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Referring to Fig. 7A, a cross-sectional view of a preferred embodiment bucking
bar 238 is presented. In
this embodiment, cap bolt fastener 250 is threadedly engaged with end of the
shaft of hammer 270 and serves to
affix hammer 270 to cap 254. Optionally, this engagement may be augmented with
a key (not shown in Fig. 7A)
interfacing between the threaded end of the shaft of hammer 270 with cap,
serving to allow user to secure fastener
250 without rotating the shaft of hammer 270. A plurality of housing fasteners
262 attach housing 260 to cap 254.
Compression spring 266 applies opposing force to distal shoulder 304, located
at end of interior cylinder stem 302 of
housing 260, and to proximal shoulder 310 of plunger 268.
Movement of plunger 268 is preferably guided by machine slide tolerances at
housing and plunger surfaces
320, bounded as shown by housing 260 and plunger 268. Movement of plunger 268
is preferably further guided by
machine slide tolerances at hammer and plunger surfaces 322, bounded as shown
by the base of hammer 270 and
plunger 268. Movement of plunger 268 is preferably further guided by machine
slide tolerances at housing cylinder
stem and plunger stem at surfaces 323; bounded by cylinder stem 302 and
plunger stem 306. Movement of plunger
268 is preferably still further guided by machine slide tolerances at hammer
stem 325 and plunger surfaces 326;
bounded as shown by hammer stem 325 and plunger 268. In this embodiment,
plunger 268 can thus only move
parallel to longitudinal axis 257.
Proximal surface 318 of housing 260 is preferably beveled as shown to reduce
potential bucker finger
pinch-point injuries. In this embodiment, conducting post 256 provides an
electrically conductive loop circuit path
from the cavity in housing 260 to the anvil face 300 through cap 254 and
hammer 270 (which conductive path is
discussed later).
In this embodiment, anvil face 300 becomes orthogonally aligned to work piece
73 and rivet shank end 70
by flush-contact between second facing surface 76 and lip or spindles feet 312
surface, located at the base of plunger
268. Unless a force greater than that exerted by compression spring 266 is
axially applied to spindles feet 312,
compression spring 266 forces plunger 268 to remain against hammer base 327.
When downward force is applied to
bucking bar 238 (with spindles feet 312 resting against second facing surface
76), preferably any possible air gap 96
between work pieces 72 and 73 is eliminated by the force exerted by
compression spring 266 on second facing work
surface 76 through spindles feet 312 of plunger 268.
= 30
In this configuration, any axial motion of plunger 268 deflects compression
spring 266. However, while
spindles feet 312 are in contact with second facing surface 76, a first
distance 314 between second facing surface 76
and anvil face 300 is directly transferred to a second distance 316 by
displacement of plunger shoulder 308. When
enough downward force is applied to the bucking bar 238, anvil face 300 comes
in contact with the rivet shank end
70, from this moment forward first distance 314 represents the height of the
forming rivet head and is sometimes
. termed the "gap height" or distance between anvil face and spindles feet or
distance between the work surface and
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anvil face. First distance 314 and second distance 316 are always equal
because first distance 314 is translated
through plunger 268 body to second distance 316.
Referring to Fig. 7B, a partial cross-sectional view of a preferred embodiment
bucking bar 238 of Fig. 7A
is presented that provides additional detail. In this embodiment, bucking bar
238 comprises a micro-adjustable
jackscrew assembly that includes jackscrew 252 coupled to cap 254 by means of
e-spring clip 258. Jackscrew 252
preferably has a small slot in its shaft to accept clip 258 and likewise
housing 260 preferably also has a small slot to
provide clearance for clip 258. Jackscrew 252 extends through cap 254 and
housing 260 and is threadedly engaged
with traveling nut 264. First sensor switch 350 is affixed to traveling nut
264 such that switch lever arm 352 may
contact shoulder 308 as second distance 316 is translated from first distance
314. Jackscrew 252 is not however
threadedly engaged with cap 254, clip 258 or housing 260. This restricts the
motion of jackscrew 252 motion to
clockwise or counter-clockwise rotational movement which movement is operative
to axially position traveling nut
264 and cause switch 350 to trip switch lever 352 on plunger shoulder 308 when
desired set rivet head height 84 is
achieved.
In this embodiment, movement of traveling nut 264 is preferably guided by
machine slide tolerances at
housing and traveling nut surfaces 366 and at plunger and traveling nut
surfaces 368; bounded as shown by housing
260 and traveling nut 264 and by plunger stem 306 and traveling nut 264,
respectively. In an alternate embodiment,
traveling nut 264 may be guided by other bodies, for example, by conducting
post 256 or a grooved slot in the body
of housing 260.
The micro-adjustable jackscrew assembly is preferably calibrated by placing a
disk or other body having
height matching a desired set rivet head height 84 on second facing surface 76
(or another surface that is equivalent
to second facing surface 76); then, bucking bar 238 is placed over the disk
and compressed until anvil face 300 is
flush against the disk and spindles feet 312 are against second facing surface
76. Next, the rivet gun operator
contacts set tool 104 against the rivet manufactured head 66 to cause bucking
bar indicator LED light 240 to
illuminate; finally, the bucking bar operator adjusts jackscrew 252 until the
bucking bar indicator LED light 240
begins to continuously flash on and off. This is a simple one-point
calibration. Some sensors require that the user be
cognizant of switch behavior such as pre-travel, otherwise known as the
movement of the actuator prior to closing
the circuit, sometimes referred to as "Travel to Make." Another switch
behavior is hysteresis described here as a
"Travel to Break." Thus the switch make and switch break positions do not
always coincide. Those skilled in the
art will recognize that employing a second switch in bucking bar 238 having
switch lever axially offset from the first
rivet set threshold (height 86 tolerance detection) switch can also be used to
overcome these problems; provided that
the offset distance is sufficient for the second switch to make after the
first switch breaks. Other calibration methods
may be used without out deviation from concept of this invention. A user
operated switch can optionally invoke the
calibration process (presented later).
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Bucking bar 238 preferably further comprises second multi-conductor cable 236
having a jack-plug
assembly 354. From jack-plug assembly 354, first internal wire 360 is coupled
to conducting post 256. Also from
jack-plug assembly 354, second internal wires 364 connect to switch 350 and
third internal wires 362 connect to
combination momentary push-button switch and indicator LED light assembly 358.
Optionally, conducting post
256 may be replaced by any electrically conductive path coupling a circuit
board to an anvil face. In application, the
described micro-adjustable mechanism is operative to allow a user to position
said first sensor so that said switching
threshold toggles when distance between anvil face and work surface is
substantially equal to said desired rivet head
height.
In this embodiment, bucking bar indicator LED light 240 shown in other
embodiments is intentionally
replaced by a combination comprising momentary push-button switch and
indicator LED light assembly 358.
Momentary push-button switch and indicator LED light assembly 358 provides the
bucker with the option of
manually indicating (second sensor) when he is "ready" to begin bucking. This
feature is considered an alternate
embodiment because, in some cases, rivets are coated with a non-conductive
material. This alternate embodiment
also includes a momentary push-button switch (not shown) on circuit board 212
(shown in other embodiments) that
also provides the rivet gun operator with the option of manually indicating
when he is "ready" to begin riveting.
Referring to Fig. 8, a preferred embodiment of the invention is presented that
preferably incorporates
bucking bar 238. In this embodiment, rivet fastening system 100 is comprised
of pneumatic rivet gun 102 that is
70 equipped with rivet set tool 104 and circuit board 212. Circuit board
212 preferably comprises mounted LED
indicator light 214, mounted LED indicator light bar 216, a set of user
selectable position switches 218, first
conducting lead wire 220 and second conducting lead wire 226, first multi-
conductor cable 232 and second multi-
conductor cable 236 and various electronic components such as a circuit
isolating photocoupler, a microprocessor, a
battery and/or an external power supply, a power regulator, and a
communication port (with these electronic
components not being shown in Fig. 8 for purposes of clarity). Second multi-
conductor cable 236 preferably
couples circuit board 212 to the bucking bar 238. The equipment shown in Fig.
8 not only accommodates the
functionality described earlier with respect to equipment shown in Figs. 5A
and 5B, but also allows for additional
capabilities to be presented later.
Contacting set tool 104 with rivet manufactured head 66 and/or first work
piece 72 closes a first loop
circuit (second sensor) formed by first conducting lead wire 220 and second
conducting lead wire 226. Upon
detection of this first completed circuit, the microprocessor illuminates
mounted LED indicator light 214 and
bucking bar indicator LED light 240 located on circuit board 212 and bucking
bar 238, respectively; this indicates to
both operators that the rivet gun operator is "ready" to begin riveting. In an
alternate embodiment, another sensor
technology is used to replace first conducting lead wire 220. For example, a
touch capacitance sensor mounted on
= circuit board 212 that is coupled to second conducting lead wire 226 to
sense contact between set tool 104 and
manufactured head 66.
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When bucking bar indicator LED light 240 illuminates, the bucker then backs up
rivet shank end 70 with
bucking bar 238. This action compresses plunger 268 which applies force to
second work piece 73 to eliminate any
air gap 96. Plunger 268 is further compressed until anvil face 300 of bucking
bar 238 contacts rivet shank end 70
forming a second loop circuit through a first path (second conducting lead
wire 226, set tool 104, manufactured head
66 and/or first work piece 72, the bucking bar anvil, and second multi-
conductor cable 236) or alternately through a
second path (first conducting lead wire 220, first work piece 72, common rivet
62, the bucking bar anvil, and cable
236). Upon detecting this second loop circuit (another second sensor) the
microprocessor continuously flashes
indicator LED lights 214 and 240 on-and-off to indicate to both operators that
the bucker is also "ready" to begin
riveting. Furthermore, the microprocessor also then operates controller 904 to
open solenoid valve 112 to enable
operation of rivet gun 102.
While common rivet 62 is being driven, rivet head 86 forms until it meets the
desired rivet head height 84.
Also, while common rivet 62 is being driven, plunger 268, acting against
second facing surface 76 is further
compressed. Upon achieving the desired head height 84, a switch is toggled by
the axial motion of plunger 268; this
forms a third loop circuit (first sensor) using at least two conductor wires
in second multi-conductor cable 236.
When this third circuit is detected, the microprocessor preferably turns off
mounted LED indicator light 214 and
bucking bar indicator LED light 240 and then closes solenoid valve 112 (using
controller 904) to disable rivet gun
102, thereby stopping rivet gun 102. Mounted LED indicator light 214 and
bucking bar indicator LED light 240
being turned off or rivet gun 102 being disabled, serves to indicate to both
operators that the rivet has been set. A
timing delay is then started by the microprocessor before enabling a new
riveting cycle. In this way, the
microprocessor sequentially controls each stage of the rivet setting cycle.
This sequencing prevents, for example,
the bucker from indicating the he is "ready" until after the rivet gun
operator has indicated that he is "ready."
in an alternative embodiment, detection of a closed loop circuit when set tool
104 contacts rivet head 66
may be achieved by detecting a loop circuit formed by first conducting lead
wire 220 and second conducting lead
wire 226 at circuit board 212. Similarly, a loop circuit is completed at
circuit board 212 when both (1) set tool 104
contacts rivet manufactured head 66 and (2) anvil face 300 contacts rivet
shank end 70 forming a contact circuit
through second conducting lead wire 226 and second multi-conductor cable 236.
Detection of these loop circuits
may be achieved by any means including measuring conductivity or electrical
resistance in the loop to determine if
the loop circuit of interest is open or closed, and/or detecting an applied
voltage from one side of the loop circuit
with a microprocessor.
In an alternate embodiment, second multi-conductor cable 236 is replaced by
radio frequency (RF),
infrared or by other wireless communication. In this embodiment, bucking bar
238 is provided with a separate
circuit board, with both the circuit board 212 and the separate circuit board
being equipped with RF transceivers for
purposes of wireless communication. In this alternate embodiment, another
conducting lead wire may extend from

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bucking bar 238 to work piece 72 or 73 that would be closed when anvil face
300 contacts rivet shank end 70. In
still another alternate embodiment, first conducting lead wire 220 and the
other conducting lead wire described
above may be eliminated by using sensors from other sensing technologies such
as capacitance sensors at circuit
board 212 and at the separate circuit board described above for detecting
contact of set tool 104 or anvil face 300
with rivet 62. Any other contact detector method or sensing technology may be
incorporated into the invention
without deviation from the inventive concept.
In an alternate embodiment, first conducting lead wire 220 can be eliminated
by including at least one
detecting loop circuit (not shown in Fig. 8) on circuit board 212. In this
embodiment, work pieces 72 and 73 are
coupled to the same electrical ground potential as the power supply to circuit
board 212. Here a detecting loop
circuit on circuit board 212 detects when components are electrically sourcing
a small amount of current directly to
ground potential. A first detecting circuit (second sensor) identifies when
set tool 104 contacts rivet head 66 by
detecting sourcing current to ground via second conducting lead wire 226, set
tool 104, rivet head 66, and work
pieces 72 or 73 to ground (not shown). Likewise a second detecting circuit
(another second sensor) identifies when
bucking bar 238 anvil face 300 contacts rivet shank end 70 by detecting
sourcing current to ground via second multi-
conductor cable 236, first internal wire 360, conducting post 256, anvil face
300, rivet shank end 70, and work piece
72 or 73 to ground (not shown). Also optionally a third detecting circuit
identifies when spindles feet 312
(discussed later) of plunger 268 contact surface 76.
Referring to Fig. 9, a perspective view of an alternate embodiment of bucking
bar 238 is
presented. A person having ordinary skill in the art will understand that the
configuration presented in Fig. 7B may
be modified in any way to adapt the described bucking bar 238 to specific
riveting applications (this is the reason for
multiple configurations of conventional bucking bars shown in Figs. 1A-1D).
However, it is acknowledged that, in
some cases, riveting in extremely congested areas may limit the use of a
preferred embodiment bucking bar 238. In
these cases, use of the alternate embodiment of bucking bar 238 shown in Fig.
9 may be appropriate. The alternative
embodiment of bucking bar 238 of Fig. 9 differs from the preferred embodiment
of bucking bar 238 of Fig. 7B in
that plunger 268 preferably comprises a stem (spindles feet 312) that extends
through bucking hammer 270 and
beyond anvil face 300. In this embodiment, cap 254 houses all other components
previously described and those
skilled in the art would appreciate design considerations needed for
construction of the alternative embodiment,
given the teachings of this disclosure. The alternative embodiment of bucking
bar 238 shown in Fig. 9 is preferably
functionally the same as the preferred embodiment of bucking bar 238 shown in
Fig. 7B except that spindles feet
312 in the alternative embodiment do not shroud the rivet head, preventing
bucking bar 238 from slipping off a
forming rivet head. Alternately, Fig. 9 exhibits the end of a LVDT sensor
protruding beyond the anvil face 300 of
bucking bar 238. Use of a LVDT sensor demonstrates an alternative sensor
technology that may be better suited for
congested spaces and provides an analogue output signal that can be configured
to detect the desired rivet head
height for a plurality of rivet sizes. Those skilled in the art will
understand that analogue sensors provide continuous
measurement of distance or displacement between the work surface and the anvil
face; also an analogue sensor
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serves as a first sensor when said distance is substantially equal to a
desired rivet head height and also serves as a
third sensor to measure a protruding shank length for determination of rivet
size and corresponding desired rivet
head height (this is discussed later).
Referring to Fig. 10, a block diagram of a preferred embodiment of
microprocessor 500 is presented. In
this embodiment, microprocessor 500 comprises bus 508 or another communication
device to communicate
information, and processor 502 coupled to bus 508 to process information.
While microprocessor 500 is illustrated
in Fig. 10 as having a single processor, microprocessor 500 may include
multiple processors and/or co-processors.
Microprocessor 500 preferably further comprises random access memory (RAM) 504
and/or another dynamic
storage device 510 (also referred to herein as memory 510), coupled to bus 508
to store information or instructions
to be executed by processor 502. Random access memory 504 may also be provided
to store temporary variables or
other intermediate information during execution of instructions by processor
502.
Microprocessor 500 may also comprise read only memory 506 (ROM) and/or another
static storage device
coupled to bus 508 to store static information and instructions for processor
502. Data storage device 510 is
preferably coupled to bus 508 to store information and instructions.
Input/output device(s) 512 may include any
device known in the art to provide input data to a microprocessor 500 system
and/or receive output data from
microprocessor 500 system.
In preferred embodiments, instructions are provided to memory 504 from a
conventional storage device
510, such as a magnetic disk, Electrically Erasable Program Memory (EEPROM),
read-only memory (ROM) 506
integrated circuit, CD-ROM, DVD, via a remote connection that is either wired
or wireless, providing access to one
or more electronically-accessible media, etc. In alternative embodiments, hard-
wired circuitry can be used in place
of or in combination with software instructions. Thus, means for execution of
sequences of instructions in
accordance with the invention are not limited to any specific combination of
hardware circuitry and software
instructions.
In a preferred embodiment, sensor interface 514 allows microprocessor 500 to
communicate with one or
more sensors within rivet fastening system 100. For example, sensor interface
514 may be configured to receive
output signals from one or more switches that detect switch states of the
components of rivet fastening system 100
as described herein. Sensor interface 514 may be, for example, an analog-to-
digital converter that converts an
analog voltage signal generated by a LVDT sensor to a multi-bit digital signal
for use by processor 502.
In a preferred embodiment, processor 502 analyzes sensor input data and
transmits signal to indicator
lights, graphical user interfaces (GUIs) such as LCDs through input/output
device(s) 512 to allow communication
between operators or to allow operator calibration of bucking bar 238.
Additionally, in an alternate embodiment,
second multi-conductor cable 236 is replaced by wireless signals such as radio
frequency or infrared. In this
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configuration, each of at least two microprocessors 500 may be coupled
wirelessly such as with to radio frequency
transceivers to communicate signals characterizing the state of the rivet
driving process between the rivet gun
operator and the bucker as described in this disclosure. Alternately other
wireless communication means such as
infrared may be used.
Processor(s) 502 may also cause system components to take other actions in
response to signals from the
sensors. For example, processor(s) 502 may use controller 904 to cause
solenoid valve 112 to open or close thus
enabling or disabling rivet gun 102. Microprocessor 500 may also be a
microcomputer, a microcontroller, a
computer, or logic circuits such as Transistor Transistor Logic (TTL) or Field
Gate Programmable Array (FGPA).
Referring to Fig. II, a schematic block diagram of control system 520 is
presented. In this embodiment,
control system 520 comprises microprocessor 500 or computer 522 as another
representation of a microprocessor
500 for acquiring and processing data relating to the rivet driving cycle or
process. In this alternate representation,
additional equipment is provided although those skilled in the art will
recognize functional equivalences of
equipment portrayed in Fig. 10 and Fig. 11 to achieve a useful working system.
Preferably, control system 520
includes power subsystem 524, sensor array subsystem 526, and control and
communication subsystem 528. Power
subsystem 524 preferably includes rechargeable battery 530 for powering
control system 520, and power regulator
532 for power control and recharging battery 530. External power supply 534
may be used to supply charging
power or optionally to replace the battery 530. Power from regulator 532 is
supplied to microprocessor 500 and
(optionally) to solenoid 540 and (optionally) may facilitate supplying power
to other components of control system
520. Controller 904 (not shown) preferrably lies between microprocessor 500
and solenoid 540;.however by
definition if microprocessor can source enough current to drive valve directly
then controller 904 is considered to be
part of microprocessor.
In this embodiment, sensor array subsystem 526 includes bucking bar sensors
536 and rivet gun sensors
538. Control and communication subsystem 528 preferably includes a pneumatic
solenoid 540 also having a driver
relay or controller, communication indicator(s) 542, such as LEDs and or LED
light-bars, communication port 544
for down loading data logged recordings of set rivet head heights for process
quality assurance/quality control
purposes (which may optionally include at least one of radio frequency (RF)
transmitter, receiver and transceiver),
graphical user interface (GUI) 546 for operator interfacing with control
system 520 and keypad 548 also for operator
interfacing with control system 520.
In operation of preferred embodiments of the invention, data generated by each
of the components of
sensor array subsystem 526 are transmitted to microprocessor 500 where the
data are processed and stored. Bucking
bar system control commands are preferably then transmitted to control and
communication subsystem 528 where
solenoid operation is determined, communication of rivet cycle stage is
indicated, user interface is achieved and
data-logged rivet head setting data are transmitted to other media via a
transceiver or by other means. Control
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system 520 is depicted with a microprocessor 500 although those skilled in the
art will know that a microprocessor
may be a microcontroller, a computer, or any arrangement of other digital
logic equipment to achieve described
system control.
Referring to Fig. 12, a schematic flow diagram of a preferred embodiment of
bucking bar software
instructions is presented. In this embodiment, because microprocessor 500
governs sequential riveting steps, when
rivet fastening system 100 is started, microprocessor 500 immediately
initializes system components in initialize
step 550 by setting variables, inputs and outputs, and setting the solenoid to
disable the rivet gun.
Next, in this embodiment, microprocessor 500 preferably waits for a received
sensor signal to indicate that
the rivet-gun operator is "ready" in detect "AG Ready" step 552; in gun ready
conditional step 554 forces the
sequencing process. Next, a rivet driving cycle is begun when microprocessor
500 detects an affirmative signal
from gun ready conditional step 554; microprocessor 500 then responds by
illuminating rivet gun operator and
bucker indicator lights to turn LEDs on in step 556 to indicate to both
operators that the rivet gun operator is ready
to begin riveting.
Next, in this embodiment, microprocessor 500 waits for a received sensor
signal to indicate that the bucker
is "ready" in detect "BB Ready" step 558; bucker ready conditional step 560
forces the sequencing process. When
microprocessor 500 detects an affirmative signal from bucker ready conditional
step 560, it continuously flashes
both indicator lights on-and-off, preferably starts an optional first time
delay to provide the operators a final moment
before riveting begins and then enables the rivet gun to initiate riveting
step 562. The flashing lights indicate to both
operators that the bucker is "ready" to begin riveting. In an alternate
embodiment, microprocessor 500 may
automatically start the rivet gun to eliminate the need for the rivet-gun
operator to depress the rivet-gun trigger.
Next, in this embodiment, microprocessor 500 waits to receive a sensor signal
to indicate that the riveting
has begun in detect start rivet step 564; rivet start conditional step 566
forces the sequencing process. When an
affirmative signal is detected in rivet start conditional step 566,
microprocessor 500 starts a timer and counts the
number of impact blows from rivet gun 102 while simultaneously waiting to
receive a rivet head height threshold
detection in start timer/count impacts step 568; detect height threshold
conditional step 570 forces the sequencing
process. A limit threshold sensor is preferably used to detect when the height
of the rivet's desired set rivet head
height 84 is reached in the driving process. Thus, while waiting for an
affirmative detection signal in detect height
threshold conditional step 570, microprocessor 500 counts the number of rivet-
gun impacts by the number of
toggled switch states of the bucking bar anvil face 300 contacting rivet shank
end (upon each impact the bucking bar
anvil face 300 is bounced off the rivet head forming a switching cycle; and in
preferred embodiments
microprocessor 500 "debounces" the signal to match the rivet-gun operating
frequency). Debounced signals
comprise a form of an impact sensor. Alternately, to detect rivet gun blows or
impacts, an accelerometer may be
used as another form of impact sensor.
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Also incorporated in step 568 is an interrupt service request (IRQ) that
activates if either the bucker or the
rivet gun operator disengages the work during the rivet driving stage. The IRQ
in step 568 stops the rivet gun in step
582 conducts a time delay, indicates an error via a LED signal and returns
control to step 550. This is particularly
important because if the bucker were to disengage the bucking bar from the
rivet during the rivet driving stage, a
damage event condition would be produced; in this case additional hammer blows
from the rivet gun would then
damage the work. The described bucker "ready" detection sensor is preferably
used to detect bucking bar
disengagement during the driving stage and preferably stop the rivet gun
immediately to prevent any hammer blows
to work that is not backed by the bucking bar. [More details of this feature
are presented later].
In this embodiment, after detecting an affirmative signal in detect height
threshold conditional step 570,
then in step 572 microprocessor 500 disables rivet gun 102: stopping rivet gun
102, stops the timer started in start
timer/count impacts step 568, turns off the indicator lights and starts a
second user selectable time delay. The
second time delay allows the rivet gun operator to remove rivet gun 102 from
the work prior to start the next rivet
cycle. Meanwhile to improve set rivet property, microprocessor 500 then
preferably determines rivet strength
according to set tolerance level and a material stress-strain curve using the
previous setting time and/or number of
hammer blows measured in start timer/count impacts step 568 and then displays
recommended rivet gun air
regulator setting modifications to the rivet gun operator who may then adjust
the impacting force (regulated air
pressure setting) supplied to rivet gun 102. In an alternate embodiment,
microprocessor 500 makes rivet-gun air
regulator setting changes automatically through feedback control of an electro-
mechanical air regulator (not shown).
Finally, after the completion of the time delay set in end riveting step 572,
the rivet driving cycle is
completed and microprocessor 500 returns to initialize step 550, although
display results generated in end riveting
cycle step 572 are not cleared from the display until an affirmative signal is
detected at ready gun conditional step
554 in the next rivet setting cycle. This allows the rivet gun operator
additional time between rivet cycles to adjust
rivet gun air regulator pressure settings. If at any time the desired set
rivet head height threshold is detected, an
interrupt service request in first interrupt service request step 574 forces
operation to reset to end riveting cycle step
572. IRQ in step 574 serves as software redundancy to rivet head height
detection in step 568.
Referring again to Fig. 12, still another interrupt service request (IRQ) is
preferably provided in second
interrupt service request step 576 upon detection of the user's toggling a
switch to manually enter a calibration mode
or, optionally, if the total number of rivets exceeds a predetermined number
since the last time a calibration was
conducted, a forced calibration is initiated in step 578 (control system 500
preferably counts the number of rivets
driven by counting the number of rivet cycles in step 572). In calibration
mode step 580, the user calibrates the
bucking bar to set the rivet head height detection threshold to achieve
setting rivets to a desired optimal tolerance.
After calibration mode in step 580, operation is returned to step 550.

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During the rivet driving stage, the loop circuit detecting contact between
anvil face 300 and rivet shank end
70 exhibits a significant amount of switch chatter 371 (rapid opening and
closing of contacts) indicative of extreme
vibration and/or shock. However by coupling at least one of a hardware and a
software low-pass filter to
"debounce" the signal for this circuit, the rivet gun hammering cycle can be
identified. This information may be
then used to automatically determine if the bucker inadvertently disengaged
bucking bar 238 anvil face 300 from
rivet shank 70 during the rivet driving stage and would then produce a
software interrupt service request to
immediately stop the rivet gun. Bucking bar removal from work during the rivet
driving stage can be detected
automatically regardless of the many variables presented earlier (such as
variations in bucking bar mass, rivet gun
mass, applied user forces, air regulator settings, etc.). The benefit of
detecting bar disengagement during the driving
stage is protection to the work from hammering on work that is not backed by a
bucking bar. In this case bucking
bar disengagement or removal is defined as removing the bucking bar anvil face
300 from rivet shank 70 to stop
backing the rivet; it is not a result of anvil face 300 being momentarily
"bucked" off the shank 70 as a result of the
normal rivet driving stage cycle.
Furthermore, while adding a dampener to the rivet plunger system was
considered by the applicant as a
way to further stabilize the bucking bar, users prefer a bucking bar that
allows them to "feel" the work. However,
adding a dampener in an alternate embodiment is envisioned by the applicant.
In summary, a low pass filter can be used to "debounce" signals to accommodate
for mechanical and/or
electrical bouncing of the bucking bar anvil face 300 on the forming rivet
head. These data may be used to prevent
inadvertent damage to the work by hammering on unbacked work by disabling the
rivet gun, if either operator
disengages their tool from the work during the rivet driving stage. Premature
tool disengagement during a rivet
driving stage is a damage event condition. Optionally, by determining the
hammer period and identifying each
falling-edge-signal, system 100 may determine that the anvil face 300 is in
contact with rivet shank end 70 just
before the rivet gun "hammers" again (or just before a few milliseconds more
than it takes to disengage the rivet gun
before the next "hammer" commences).
Referring to Fig. 13, a partial cross-sectional view of still another
alternate embodiment of bucking bar 238
is presented to further illustrate another possible configuration. This
embodiment combines a cap portion and an
anvil portion to form hammer 270 having a reduced diameter anvil face 300.
Compression spring 266 applies force
to plunger 268 which is retained by housing 260 at housing shoulder 611.
Plunger 268 is guided by a groove, key or
axially-positioned tab 704 in housing 260 restricting plunger motion to axial
travel. Housing 260 is secured to
hammer 270 by a plurality of housing bolt fasteners 262.
In this embodiment, a slotted photo switch 605 is a first sensor and is
preferably retained in a cavity in
housing 260 by the shape of said cavity or by adhesive. Cap screw 600 is
threadedly engaged with threaded
plunger 268 as shown to allow axial micro-positioning and adjustment of photo
switch 605 operation during
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calibration process by adjusting cap screw 600 (discussed later). Photo switch
605 toggles switch state when
interrupted by the head of cap screw 600. Thus cap screw 600 serves as a
mechanical flag to interrupt photo switch
605. Access port 602 allows the user to adjust by rotation of cap screw 600
either clockwise or counterclockwise to
axially position cap screw 600 to a desired location.
Upon assembly of this embodiment of bucking bar 238, slotted photo switch 605
is secured to housing 260
with photo switch 605 connected to multi-conductor cable 237 with cable being
secured by strain relief device 606
which is preferably threadedly attached with body of housing 260 to support
multi-conductor cable 237. Next,
compression spring 266, plunger 268 (with pre-installed cap screw 600) and
housing 260 are sequentially installed.
These components are all held by housing 260 and housing 260 is then affixed
to cap end of hammer 270 by housing
bolt fasteners 262. A plurality of bolt fasteners 262 are threadedly engaged
with the body of housing 260. Multi-
conductor cable 237 is coupled to bucker control circuit board 212' upon which
is mounted bucking bar indicator
LED light 240. Bucker control circuit board 212' preferably communicates with
rivet gun control circuit board 212
via radio frequency signals 992. Bucker control circuit board 212' may be
affixed to the bucker's wrist by means of
a Velcro fastener, affixed to bucking bar 238 or integrated into bucking bar
238.
In operation, the bucker calibrates bucker bar 238 by setting plunger 268
spindles feet to desired set rivet
head height 84 relative to anvil face 300 and then adjusting cap screw 600
until photo switch 605 toggles; a
successful calibration is indicated by threshold illumination of bucking bar
indicator LED light 240. It is noted in
this configuration that during calibration a cap screw adjustment tool (not
shown in Fig. 13) will give false detection
indication at LED 240 and therefore adjustment tool must be repeatedly removed
from slot 602 after having made
fine adjustments to the cap screw 600 axial position until desired set rivet
head height 84 is detected by interruption
of photo switch 605 by head of cap screw 600.
Referring to Fig. 14, a partial cross-sectional view of still another
alternate embodiment of the invention is
presented. In this alternate embodiment the teachings of this invention are
applied to the rivet set tool for use in
backriveting. Those skilled in the art will recognize that the provided
teachings of both bucking bar and rivet set tool
systems are similar in functional design and operational practice to produce
the same desired results. There is no
functional difference between a rivet that has been forward set vs. a rivet
that has been backset; in some cases it is
the operator's choice to select the rivet-setting tool used based on working-
space restrictions and in other cases it
only user preference. Consequently, means and method of operation for the set
tool in Fig. 14 is similar to bucking
bar tools and vise versa. Backriveting system 640 is preferably used in
situations where a conventional bucking bar
is placed over the manufactured head of flush rivet 64 or of universal head
rivet 62 (preferably with concave cup
shape ground into anvil face of bucking bar to accommodate universal head
rivet 62 shape) and the rivet gun set tool
is used to form driven rivet head 86.
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In this embodiment, backriveting system 640 comprises rivet set tool 104
having anvil face 300.
Compression spring 266 is retained by internal collar 654 and setscrew 656.
Compression spring 266 applies force
to plunger 268. An access port through plunger 268 allows setscrew 656 to be
tightened into a recess in set tool 104.
Set screw 656 is threadedly engaged with collar 654. Embedded in plunger 268
is first sensor rnicroswitch 352
having switch lever arm 351 which actuates on the shoulder of external collar
650 which is secured to set tool 104
by external setscrew 652. Set screw 652 is threadedly engaged with collar 650.
During assembly, plunger 268, compression spring 266 and collars 654 and 650
are slid onto set tool 104.
External collar 650 is used to position internal collar 654 and compress
spring 266 until internal setscrew 656 is
fastened. This secures plunger 268 on set tool 104. Next, plunger 268 is
positioned to desired set rivet head height
84 and external collar 650 is then positioned such that it just toggles switch
lever arm 351 when external collar 650
is secured to set tool 104 with external setscrew 652. Actuation of
microswitch 351 is indicated by illumination of
an LED and/or solenoid closure that is not shown on Fig. 14 when gap height
314 or the distance between spindles
feet (resting on work surface) and anvil face 300 achieve a desired driven
rivet head height 84. It is further noted
that although a small timing delay may be preferred, system 640 may
alternately be used in wireless (RF)
applications as a detector for detecting when the set tool contacts a
manufactured head to detect (by toggling switch
351 with a small motion of plunger 268) when the rivet gun operator is "ready"
to begin riveting. (This is another
example of how one could eliminate the need for conducting wires 220 and 226
shown in Fig. 8; more examples will
be shown later).
Referring to Fig. IS, a partial cross-sectional view of still another
alternate embodiment of the invention is
presented. In this embodiment, bucking bar 238 comprises a micro adjustable
system (operated by manual rotation
of plunger 268) and further comprises first switch 708 to detect the initial
motion of plunger 268 for the purpose
of detecting when the bucker is ready. This embodiment is particularly useful
in a wireless system such as RF
(which could replace multi-conductor cable 236) in which circuit closure
cannot be detected by means of a circuit on
the rivet gun side. It should be noted that the embodiment in Fig. 15 could be
further simplified by removing collar
706 and embedding second switch 710 (a first sensor) into sidewall of housing
260 or embedding second switch 710
into cap end of hammer while maintaining the same functionality.
Similar to the embodiment shown in Fig. 13, the embodiment of bucking bar 238
shown in Fig. 15
combines the cap and anvil to form hammer 270 having a reduced-diameter anvil
face 300. Compression spring 266
applies force to plunger 268 which is retained by housing 260. Housing 260 is
secured to hammer 270 by a plurality
of housing bolt fasteners 262. Compression spring 266 may be any type of load
source.
In this embodiment, plunger 268 is preferably retained in housing 260 by the
shoulder of plunger collar 712
on shoulder of housing 713 while plunger 268 is threadedly engaged with
threaded traveling nut 702. Threaded
traveling nut 702 is preferably guided by a groove, key or axially-positioned
tab 704 in housing 260. Tab 704 thus
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prevents rotational motion of threaded traveling nut 702, thereby restricting
traveling nut 702 to axial movements.
This configuration allows the user to rotate plunger 268 clockwise or
counterclockwise relative to housing 260 by
grasping it at its exposed end (near anvil face 300), to position threaded
traveling nut 702 within housing 260 cavity.
The threaded engagement between plunger 268 and threaded traveling nut 702
provides sufficient friction to prevent
inadvertent rotation of plunger 268 and guide marks (not shown) on the outside
of plunger 268 may be aligned with
similar guide marks (also not shown) on the outside of housing 260 for
position referencing of threaded traveling nut
702. (All threaded engagements described in this disclosure are preferably
provided with sufficient friction to
prevention inadvertent or unintended movement or rotation.)
In this embodiment, first embedded switch 708 is embedded in housing 260 and
when plunger 268 is not
deflected by first distance 314, the shoulder of plunger collar 712 holds the
switch actuation lever down due to the
force exerted by compression spring 266. Thus, with only a slight axial
movement of plunger 268, a switch state
change is detected at first embedded switch 708 as collar 712 of plunger 268
moves off of the switch actuation lever.
This detection feature, combined with a small timing delay in a
microprocessor, may be used to detect when the
bucker has indicated that he is "ready" to begin bucking. Also as previously
indicated when discussing Fig. 8, an
alternate embodiment for detecting when the bucker has indicated that he is
"ready" to begin bucking by detecting a
sourced current from power supply of circuit board 212 to electrical ground
via bucking bar anvil face 300 contacts
the rivet shank end 70, rivet 68, a first or a second work piece (72 or 73) to
a ground (not shown in Fig. 15) sharing
the same electrical ground potential as the power supply. Although not
limiting, those skilled in the art will
recognize an optical photo coupler integrated circuit provides an example
means to detect a sourced current to
ground and may be used to detect any anvil face contact with a rivet or any
spindles foot contact with a work surface
(described later). The purpose of demonstrating use of alternate embodiment
from Fig. 8 in Fig. 15 is to further
demonstrate that the teachings of the invention can be modified in a number of
respects by a person skilled in the art
to produce a multiplicity of embodiments of the invention, all without
departing from the concept.
In this embodiment, second embedded switch 710 is embedded into cylindrically-
shaped switch housing
collar 706. Compression spring 266 fits into a recess in switch housing collar
706 and securely maintains switch
housing collar 706 firmly against the cap of hammer 270. Collar 706 is also
engaged with tab 704 to prevent collar
706 rotation relative to hammer 270 shaft. Second switch 710 is also located
near the outside diameter of switch
housing collar 706. In this configuration, displacement of plunger 268 by
distance 314 is translated into distance
316 by the shoulder of threaded traveling nut 702, but threaded traveling nut
702 is limited in travel by contact with
switch housing collar 706. However, slightly before threaded traveling nut 702
abuts the shoulder of switch housing
collar 706, the shoulder threaded traveling nut 702 actuates the switch lever
of second embedded switch 710,
resulting in a switch state change. This switch state change is detected at
second embedded switch 710 and
indicates that the desired set rivet head height 84 has been achieved.
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It is noted that a second compression spring (not shown) could be affixed to
second embedded switch 710
to allow plunger 268 to move distance 314, causing the end of traveling nut
702 to press against second switch 710
and thereby causing the state of switch 710 to toggle. Should traveling nut
702 rapidly impact against second switch
710, the second compression spring would then compress allowing second switch
710 to recess into a receiving slot
in switch housing collar 706, thereby protecting second switch 710.
Furthermore, plunger travel 314 is allowed to
travel until flush with (and preferably slightly beyond) anvil face 300 before
limiting the travel of the shoulder of
threaded traveling nut 702 at switch housing collar 706. This embodiment would
serve to protect the spindles feet
end of plunger 268 from damage if the tool were to be accidentally dropped,
and to protect damage to the engaged
threads of plunger 268 and traveling nut 702 and to protect second switch 710
from possible crushing damage from
the traveling nut 702. Wires extending from first and switches 708 and 710;
respectively, to second multi-conductor
cable 236 are not shown in Fig. 15 for the purposes of clarity. Furthermore,
from these teachings, it should be
understood that second switch 710 could also be embedded into the cavity
sidewall of housing 260 while still being
operative by traveling nut 702, thereby simplifying the design.
Referring to Fig. 16, a perspective view of still another alternate embodiment
of bucking bar 238 is
presented. In this view, spindles feet 312 and anvil face 300 are shown. In
this alternate embodiment, spindles feet
electrical conducting contact points (first contact point 312', second contact
point 312" and third contact point
312") are located as shown 120-degrees apart. When bucking bar 238 is oriented
orthogonal to second work piece
73, said contact points communicate with second facing surface 76 (work
surface). To ensure positive
communicative contact with work, contact points 312', 312" and 312" become the
spindles feet 312 and may be
slightly raised or protrude above the spindles feet 312 surface (cylinder
plane formed by end of plunger 268). Each
contact point is wired to a second microprocessor (conducting wires and second
microprocessor are not shown in
Fig. 16 for purposes of clarity). Coupled with microprocessor software, the
contact points 312', 312" and 312"
constitute at least one loop circuit and form at least one fourth sensor to
detect when spindles feet 312 is in planar
contact or near planar contact with second facing surface 76 (i.e., when
bucking bar 238 is orthogonal or nearly
orthogonal to second facing surface 76; second facing surface 76 is a work
surface).
In a first configuration, operation of the bucking bar embodiment of Fig. 16
is understood by referring back
to Fig. 8: When used in bucking bar system 100, using multi-conductor cable
236, at least one of said contact points
is wired to an input channel of a microprocessor on circuit board 212 and at
least one of said contact points is wired
to an output channel of a microprocessor on circuit board 212. When bucking
bar 238 is orthogonally or about
orthogonally positioned with spindles feet 312 and said contact points rest
against second facing surface 76, at least
one additional loop circuits (fourth sensor) are formed. Those skilled in the
art will recognize a plurality of possible
circuit paths for sensing spindles feet contact with work surface. One circuit
path is from circuit board 212 to work
surface via wire 220 or 226 and then to spindles feet via work surface.
Another circuit path is from to one of the
spindles feet and conducted across work surface to at least one of the other
spindles feet. Still another circuit path is
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In a second configuration, the bucking bar embodiment of Fig. 16 is used in a
wireless application. In a
wireless application, a second circuit board 212' (not shown) is located on or
near bucking bar 238 and preferably
having RF transceiver for communication with a first circuit board 212 (also
not show). Each of contact points 312',
312" and 312" is each independently wired to its own input channel to the
second microprocessor. In this second
configuration, the correct orthogonal position of bucking bar 238 is detected
by testing continuity loops formed
between contact points 312', 312" and 312" using contact with second facing
surface 76 to close the loop circuits.
In a first example, continuity is tested between contact points 312' and 312"
and then in near-real-time tested
between contact points 312" and 312". This forms a three-point plane test to
determine if orthogonal positioning
has been achieved. In a second example, power is supplied from the second
circuit board to contact point 312' and
is detected through the work at contacts 312" and 312" to determine if
orthogonal positioning has been achieved.
(Note: Both first and second configuration examples may also be used to
replace switch 708 in Fig. 15 to detect
when the bucker is "ready" since power supplied at any of the contact points
312', 312", or 312" may be used to
form a circuit path by contacting anvil face 300 with rivet shank end 70 via a
wire affixed to conducting post 256,
for example. Another way is to detect continuity across at least two of said
contact points as a test condition for rivet
tool operation. Furthermore, failure of this condition could automatically
cease rivet driving and produce a tool
alignment error indicated to operators by a unique LED flashing pattern).
This alternate embodiment may optionally also include three indicating LEDs
[first indicating LED (not
shown), second indicating LED 240" and third indicating LED (not shown)]
similarly located 120-degrees about
housing 260 or cap 254. This is illustrated in Fig. 16 by LED 240" located in
the same axial plane as second
contact point 312". Thus, depending on whether the first or second
configuration described above is used, the
second microprocessor can identify during the rivet driving stage which
contact point(s) are not in communication
with second facing surface 76 and illuminate at least one LED to indicate to
the bucker a suggested appropriate
bucking bar 238 positioning corrective action. This provides a user with a
tool alignment aid. For example, if
contact points 312' and 312" are detected but contact point 312" is not
detected, the microprocessor illuminates or
flashes second indicating LED 240" to indicate to the bucker to tip bucking
bar 238 towards illuminated second
indicating LED 240". Then, after the bucker has made the appropriate bar 238
positioning correction, the
microprocessor stops illumination of second indicating LED 240". It is
understood that the indicating LEDs may
also be used to illuminate the work while still serving to indicate bar 238
alignment corrections to the bucker. In
such a case, turning the indicating LED lights off or flashing lights may be
used as a tool alignment aid to indicate to
the bucker a direction of bucking bar 238 correction movement to achieve
orthogonal alignment.
A person having ordinary skill in the art would understood that although in
the illustrated embodiments
three contact points are used to detect tool alignment (in that three-points
define a plane), due to the geometry of
spindles feet 312, two points and potentially only one point may also be used
to achieve the same result. Also, more
than said three contact points may also be used to achieve the same result.
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A person having ordinary skill in the art would also understand that although
electrical contact points are
illustrated, any contact detection sensor, device or devices, such as a
plurality of switches appropriately positioned
about the spindles feet 312 could also be used without deviating from the
concept of this alternate embodiment. In
another example, using these teachings, three or more LVDT sensors may be used
to determine alignment of anvil
face 300 plane to the work surface plane, allowing the microprocessor to
provide LED indication to the bucker to
make small tool alignment corrections to the position of bar 238 to achieve
acceptable orthogonal alignment or to
allow the microprocessor to momentarily disable the rivet gun if bucking bar
238 alignment is outside an acceptable
range (this is another form of damage event condition). LVDT sensors may be
incorporated into spindles feet 312
or extend through anvil face 300 as shown in Fig. 9. A person having ordinary
skill in the art would also understand
that the teaching of this alternate embodiment may be applied to the spindles
feet of any embodiment of this
invention such as spindles feet on plunger 268 shown in Fig. 14.
To summarize Fig. 16, in this embodiment, means are proyided for achieving and
maintaining parallel
planar alignment of anvil face 300 with the work to ensure that rivet shank 68
is driven axially. Additionally,
alternate means for detecting when the bucker is "ready" are also provided.
Furthermore, means for correcting tool
misalignment relative to work surface (via LED light indication) during the
rivet driving stage is provided or,
optionally, to prevent prior art misshaped set rivets the rivet driving stage
may be interrupted by momentarily
disabling the rivet gun when unacceptable tool misalignment is detected.
Finally, those skilled in the art will
recognize that any time a rivet driving stage begins, but ends prematurely,
and not as a result of achieving a desired
rivet head height, a fault event is created and users are so notified via LED
indicators. A fault event is usually a
damage event condition but could also result from a rivet gun operator
prematurely disengaging the gun trigger
before the rivet is fully set (as detected by a first sensor and automatically
ceasing riveting). A fault event indicator
informs the users to return the unfinished rivet and recommence a rivet
driving stage until a first sensor detects that
the driven rivet head height substantially matches a desired rivet head
height.
Referring to Fig. 17, a schematic diagram of another relatively simple
embodiment of the invention (similar
to that shown previously in Fig. 5A) is presented. Although the embodiment
illustrated in Fig. 17 is not the most
preferred embodiment of the invention, it is used to simplify and teach the
invention. In this embodiment, bucking
bar system 100 comprises first battery 802 which is coupled to rivet set tool
104 of rivet gun 102. When the rivet
gun operator contacts rivet tool 104 against rivet manufactured head 66, a
first loop circuit (forming a second
sensor) is made via first LED indicating light 114 (which may also be a work
illuminating LED) to indicate to the
bucker that the rivet gun operator is ready to start riveting.
Second battery 804 is also coupled to augmented bucking bar 52' at a first end
and to second work piece 73
at a second end with fourth LED indicator light 138 disposed inline. When
bucker contacts augmented bucking bar
52' against rivet shank end 70, a second loop circuit (forming another second
sensor) is made through second work
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piece 73, illuminating fourth LED indicator light 138 to indicate to the rivet
gun operator that the bucker is ready to
start riveting. Seeing fourth LED indicator light 138 illuminate, the rivet
gun operator then begins riveting.
Next, similar to the situation described in Fig. 5A, when the desired set
rivet head height 84 is obtained, a
third loop circuit is formed from battery 806 through contact 130 (forming a
first sensor) and work and relay 808,
thereby actuating relay 808. When relay 808 is actuated, power from battery
810 is supplied to solenoid valve 112,
momentarily disabling the rivet gun power source (air supply). This signals
the rivet gun operator to discontinue
riveting and both operators then move to then next rivet.
In the embodiment shown in Fig. 17, solenoid valve 112 comprises a two-port
valve coupled inline
between the air supply and rivet gun 102. In this embodiment, the first valve
port is coupled to the air supply and
the second valve port is coupled to rivet gun 102. In an alternate embodiment,
solenoid valve 112 is a three-port
valve likewise coupled between the air supply and rivet gun 102. The first
valve port is coupled to the air supply
and the second valve port is coupled to rivet gun 102. The third valve port is
coupled to the ambient atmosphere. In
operation, when rivet gun 102 is energized, the three-port valve allows air to
pass from the air supply to rivet gun
102 (from the first port through to the second port) while the third valve
port is closed. When rivet gun 102 is de-
energized, the three-port valve disconnects the air supply while
simultaneously allowing backpressure from rivet
gun 102 to be exhausted to the ambient air (from the second port through to
the third port). In this embodiment, the
three-port valve serves to rapidly de-energize rivet gun 102 by venting
backpressure to the atmosphere and to
prevent residual rivet gun hammer blows when solenoid valve 112 decouples
rivet gun 102 from the air supply.
Referring to Fig. 18, a wiring schematic diagram is presented that is
consistent with software instructions in
accordance with a preferred embodiment of the invention. These instructions
were written and tested using a Basic
Stamp 2 microprocessor; in a production embodiment, use of an Atmel tiny
microprocessor with programming in
the C language is preferred.
In this embodiment, circuit board 212 illustrates in schematic view a
preferred wiring diagram for operation
of rivet fastening system 100. Circuit board 212 supplies power to the work
piece and to bucking bar 238 as shown.
This allows contact detection at Input-Pin0 (second sensor) when rivet set
tool 104 contacts first work piece 72 or
rivet manufactured head 66. Similarly, contact of anvil face 300 (not shown in
Fig. 18) of bucking bar 238 with
rivet is detected at Input-Pinl (another second sensor). In this schematic
configuration switch 350 is Normally Open.
Switch 350 is a first sensor and actuates when the rivet has been set; this is
detected at Input-Pin2.
Further referring to Fig. 18, Output-Pin3 preferably controls the status of
bucking bar indicator LED light
240 using a NPN type transistor 902. Output-Pin4 controls the status of
mounted LED indicator light 214. Bucking
bar indicator LED light 240 and mounted LED indicator light 214 serve to
communicate the stage of rivet setting
during each rivet setting cycle to bucker and rivet gun operator;
respectively. Finally Output-Pin5 is used to control
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the on or off status of solenoid valve 112 via controller 904. Any type of
solenoid driver, valve driver, driver or
controller 904 may be used: examples include a relay, a Field Effect
Transistor, a 555 Integrated Circuit, a NPN or
PNP transistor, or the microprocessor 500. This equipment lists many types of
controller examples and should not
be considered limiting; a controller 904 is operative to enable and disable a
rivet driver and said controller 904 is
preferably operated by a microprocessor. Therefore a signal from
microprocessor is sent to a controller 904 to cause
actuation and enable or disable the rivet driver. Also, the solenoid may be
driven directly by microprocessor
OutputPin5. In this embodiment, the closing of user activated switch 906 is
detected at Input-Pin6 to manually
place the system into a calibration mode. Additionally, calibration mode LED
908 illuminates when system 100 is
in the calibration mode via Output-Pin7 to so inform the users. Other Output
Pins (not shown) may be used with
other LEDs to direct the user to make clockwise or counterclockwise
directional adjustments of positioning
jackscrew 252 during calibration.
A person having ordinary skill in the art would understand that there are
numerous alternative structural
embodiments and alternative microprocessor instructions that could be used to
achieve the teaching of this
invention. Also, numerous components on circuit 212 have been omitted for
purposes of clarity. Furthermore, it is
also understood that if rivet fastening non-electrically-conductive work
pieces such as plastic or carbon fiber is
called for, schematic system 100, as well as its associated microprocessor
listing, could be easily modified to
maintain operator "ready" indicating status using teachings such as those
presented in Fig. 14 (that shows how a
switch system may be used to detect when set tool 104 contacts the work piece)
as well as those presented in Fig. 15
(that shows how switch 708 may be used to detect when plunger 268 contacts the
work piece).
Referring to Fig. 19, a schematic flow diagram is presented of a more
preferred embodiment of software
instructions for microprocessor 500. Since the operation of microprocessor 500
governs sequential riveting steps,
when system 100 is started at start step 950, it immediately initializes
system components in initialize system step
952, by declaring variables, setting variables, inputs and outputs, setting
solenoid 112 to disable rivet gun 102, etc.
Next, in main program step 954, system tests are conducted by poling the
status of input pins to determine
which subroutine to call. Numerous tests are performed. Example tests include
detecting whether the rivet gun
operator is ready to begin riveting; detecting whether the bucking bar
operator is ready to begin bucking; detecting
whether there is a sequence or switch fault error (primarily for purposes of
forcing the proper sequence of rivet cycle
driving stages). Another error test is to detect whether the rivet head height
detection sensor is working. Still
another test is to determine whether the rivet gun operator has set up on a
rivet and then disengaged (removed the
rivet gun set tool from the work or rivet head). Still another error test is
to determine whether the bucker has
removed the bucking bar from the rivet during the rivet driving stage. This is
an especially important test since it
prevents the air gun operator from riveting against a rivet that is not being
backed by the bucking bar; thus
preventing damage to the work (a damage event condition).
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Still further referring to the main program step 954 other tests are
conducted. The main program step 954
also detects whether the calibration mode has been requested by the user (by
switching system 100 into a calibration
mode) or alternately by the system, e.g., requiring bucking bar recalibration
after a predetermined number of rivets
have been driven. Finally, in main program step 954, the system detects when a
system reset is requested by at least
one of the users (e.g., by pressing a reset button on circuit board 212) or by
the system following the end of a rivet
driving cycle, following operation of the error management subroutine, or
following operation of the calibration
management subroutine.
In rivet gun operator ready step 956, a subroutine is invoked when main
program step 954 detects that the
rivet gun operator is ready to start riveting. In this first subroutine, the
LEDs are turned on to indicate the bucker
that the rivet gun operator is ready to begin riveting; the rivet gun
operator's LED is also turned on to verify the
described communication to the bucker.
In bucker ready step 958, another subroutine is invoked when main program step
954 detects that the
bucker is ready to begin bucking. In this second subroutine, rivet gun 102 is
enabled and the LEDs are flashed on-
and-off to indicate to both operators that the bucker is ready to begin
bucking. Meanwhile, in bucker ready step 958,
microprocessor 500 continuously monitors for system errors (to be described
later) while also continuously
monitoring for calibration requests (described earlier). Bucker ready step 958
is where the rivet driving cycle stage
is conducted. If no interrupts, such as error faults or calibration requests,
are identified in bucker ready step 958,
microprocessor 500 disables rivet gun 102 when desired set rivet head height
84 has been achieved and routes
logical control to system reset step 964 (described later).
However, still referring to bucker ready step 958, if a system error is
detected, rivet gun 102 is disabled and
logical control is passed to the error detection block 960. Another
possibility is that a calibration request is detected
in bucker ready step 958; this would cause rivet gun 102 to be disabled and
logical control to be passed to the
calibration step 962.
Next, in error detection step 960, a third subroutine is invoked by main
program step 954 or by bucker
ready step 958 as a result of detecting a system error. There are numerous
error possibilities. For example, errors
can be a result of a rivet cycle sequencing fault, such as when the bucker
attempts to indicate that he is ready to
begin bucking before the rivet gun operator has first indicated that he is
ready to begin riveting. In another example,
if the bucker removes the bucking bar from the rivet during the riveting
stage, an error is detected which stops the
riveting process to prevent damage to the work resulting from the rivet gun
hammering on a rivet that is not backed
by the bucking bar. In still another example, an error results if a desired
set rivet head height has been detected but
the bucker has not indicated that he is ready. These examples illustrate some
of the many possible fault detection
schemes. After step 960, control is passed to step 964.

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Next, in the calibration step 962, a fourth subroutine invoked by main program
block 954 or by bucker
ready step 958 as a result of detecting a request for system calibration.
Calibration step 962 allows the user to
identify how many rivets have been driven since the last calibration was
performed. This information coupled with
total elapsed riveting time can be used by management to help determine worker
performance. Additionally, since
system 100 tracks the number of rivets driven, it can automatically force a
calibration check after a predetermined
number of rivets have been set or if the user sets a calibration switch. After
step 962, control is passed to step 964.
Finally, system reset step 964 allows test parameters to be cleared or reset
before the start of each rivet
cycle. The main program step 954, as well as all described subroutines in
steps 956, 958, 960 and 962 directly or
indirectly invoke system reset block 964; the only exception is the rivet gun
ready block 956 which passes control
logic to the main program block 954. Those skilled in the art will recognize
another form of indicating is actuation
of solenoid valve either open to start a rivet driving cycle or closed to end
a rivet driving cycle.
In preferred embodiments, system 100 ensures the tool does not fall out of
calibration because it was not
recalibrated on a timely basis. Therefore, the microprocessor uses a
"debounced" signal to count the number of
rivets driven and invokes an automatic calibration check after setting a
predetermined number of rivets. Coupled
with measuring total riveting time, the user (or management) is able to assess
the rivet setting production
performance for a work shift. In preferred embodiments, the number of impacts
it takes to set a rivet and/or
measuring the rivet setting time is performed by system 100 (this is useful
for recommending and/or automatically
adjusting air regulator settings to maximize rivet strength properties by
minimizing work hardening of the rivet
material). Alternately, assessing the hammer cycle frequency and/or
"debounced" bucker contact signals, air
regulator settings can also likewise be adjusted. Those skilled in the art
will also recognize that after accommodating
for the largest variables including user applied forces, tool alignment, air
regulator settings, and tool equipment
mass; a system might alternately accurately set rivets by only controlling the
total number of impacts allowed before
ceasing riveting, i.e., limiting the total impacts for each rivet driving
stage. Total impacts can be obtained by
directly counting impacts or timing the duration of a rivet driving stage
based on the impact gun frequency. Total
impacts may be adjusted according to rivet size (a user input) or by
determining rivet size using a sensor (presented
later). This approach is considered to be a less preferred alternate
embodiment of the invention.
Referring to Fig. 20, a schematic diagram is presented that depicts
relationships among a plurality of
microprocessor units located on distributed circuit boards for a "wireless"
e.g. radio frequency (RF) embodiment of
the invention. This diagram shows that rivet gun operator control circuit
board 212 can communicate directly with
second bucker control circuit board 212' using RF signals 992 or alternately
communicate using RF signals 992 via
a RF repeater circuit board depicted as third circuit board 212". Fig. 20
shows circuit board 212' disposed outside
the housing of bucking bar 238; however, circuit board 212' may be
incorporated into bucking bar 238.
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In preferred embodiments, a RF communication scheme is used to datalog worker
progress/productivity or
other rivet setting data; when multiple workers are using this embodiment,
each circuit board preferably has a
unique RF "hand shake" address. By correlating tool RF addresses, data is
preferably transmitted via RF from at
least one of circuit board 212, 212', 212", 212" and 212" to fourth circuit
board 212" which is coupled to
central computer 994 for data logging and database purposes.
In a preferred embodiment, air solenoid valve 112 is operated by fifth circuit
board 212" having
preferably a RF transceiver or at least a RF receiver in communication with at
least one of circuit board 212, second
circuit board 212' and/or third circuit board 212". Finally, air regulator 990
is operated by sixth circuit board
212" having preferably a RF transceiver or at least a RF receiver to achieve
RF communication via 992 signals
with at least one of circuit board 212, second circuit board 212' and/or third
circuit board 212". In this embodiment,
communication between and among all circuit boards is achieved using RF
signals 992, although the applicant
alternately envisions substituting RF communication with communication wires
(not shown in Fig. 20) for coupling
communication between one or more circuit boards.
Finally, referring again to the preferred embodiment shown in Fig. 20, at
least one of circuit board 212,
212', and 212" may communicate with the fourth circuit board 212" which is
coupled to a data logging central
computer 994. Memory belonging to a central computer 994 is termed central
memory. All six of the RF circuit
boards (212, 212', 212", 212", 212", 212") preferably have transceiver RF
capability to allow
communication handshaking between each other. It is understood that each
circuit board has an RF address to
prevent unintended cross-communication with other circuit boards belonging to
other equipment not shown in Fig.
20. Those skilled in the art will appreciate that many combinations of
communication between circuit boards are
possible so the described communication combination is not to be limiting.
Also given this teaching, it should be
easily recognized that data from a plurality of users can be transmitted from
any of the circuit boards 212, 212',
212", 212", or 212" to circuit board 212" where data are stored on management
central computer 994. A data
set may comprise at least one of an equipment identification, a user
identification, a time and date stamp, a rivet
size, a desired rivet head height, a set rivet head height, a number of hammer
blows, an air regulator setting, an
offset distance, a time duration of rivet driving, a rivet gun hammering
frequency. Furthermore, it is understood by a
person having skill in the art that database information may be queried to
determine or document tool performance
or to aid manufacturers with production schedules or other purposes. In one
example, if the RF address of each
riveting tool in this invention is correlated or assigned to a user, user
performance and production could be better
assessed and managed. In a less preferred configuration of Fig. 20, data from
a data set may be transferred to central
computer 994 by other than wireless means.
Referring to Figs. 21A and 21B, more preferred embodiment of the invention is
presented. The table
shows preferred I/O Pin designations. Pin P3 represents a first sensor and
pins PO and P1 represent second sensors.
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In preferred embodiments, the solenoid only enables rivet gun for rivet
driving stage; this prevents damage
to work from inadvertent rivet gun use (another form of damage event
condition). In an alternative embodiment, the
rivet gun is "hotwired" to eliminate need for rivet gun operator to use the
rivet gun trigger (but, with this
embodiment, a user adjustable timing delay prior to starting the rivet gun may
be desired for user appeal).
Fig. 21A depicts a preferred controller 904 using a Field Effect Transistor
(FET) which is faster acting that
the 555 Integrated circuit. Parallel resistive and capacitive couplings to
ground for inputs PINO and PIN1 serve to
help eliminate false detections and a zener diode coupled to InputPin0
alternately adds additional protection. This
arrangement also helps to filter switch chatter (described later).
Working Example
Referring to Fig. 22, a digital recording of operation of a prototype of
system 100 using an oscilloscope
shows bucking bar tool-to-rivet contact signature using a preferred embodiment
of bucking bar 238; the drawing
represents bar 238 dynamic response to a rivet gun "hammer" cycle. Also, the
recording shows clear signs of switch
chatter 371 (rapid opening and closing of contacts) indicative of extreme
vibration and/or shock between anvil face
300 and rivet shank end 70. Contact bounce or oscillation of movable contact
upon closure of circuit was present as
indicated by first contact bounce signature 373. The "switch" in this case was
the make or break when the bucking
bar was in contact or bounced off (not in contact) with the forming rivet
head; respectively. When in contact, a
voltage was detected and when not in contact, no voltage was detected. The
rivet gun "hammer-blow" was
indicated by first falling edge hammer signal 375. The time interval the anvil
face 300 was '`bucked-off" the rivet
shank was shown by time interval 377. In general, there was a clear impact
signature.
Referring to Fig. 22 a rivet gun hammer cycle period was approximately 37
milliseconds (ms) which is
equivalent to about 27 Hertz. The time in contact was about 22 ms and the non-
contact time was about 15 ms. The
regulator air pressure was 90 pounds per square inch. It is important to note
that the switch chatter and contact
bounce signatures could be an artifact from the oscilloscope, switch (formed
by mechanical bouncing of the anvil
face against the rivet end) or a combination of tkese factors; however,
signatures variances from oscilloscope
measurement would be representatively equivalent in both Figs. 22 and 23 and,
therefore, for comparison purposes,
variations from the oscilloscope measurement would be consistent.
Fig. 23 shows a repeated test using a conventional bucking bar of similar
mass. A significant increase in
mechanical bouncing (anvil face on rivet head) before coming to rest was
present; indicated by the contact bounce
signature 373'. Switch chatter 371' was also present along with second falling
edge hammer signal 375'. In
general, the signature exhibited in Fig. 23 showed more vibration and was less
clearly defined compared to the
signature in Fig. 22.
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In both cases, the anvil face was abutted against the rivet shank end when the
rivet gun commenced a
"hammer". Careful observation revealed approximately equivalent hammer
frequencies. Results are presented in
Table I.
Table I.
Item Bucking bar 238
Conventional bucking bar
Time "in-contact" 22 ms 18 ms
Time "non-contact" ¨15 ms 20 ms
Mass 1 lb 10.0 oz 1 lb 7.2 oz
The findings of this experiment were that, compared to the conventional bars,
bucking bar 238 exhibited a
much more well-defined characteristic train-wave signature. The difference
between the waveform signatures of
Figs. 22 and 23 is mainly due to the plunger design of bar 238. The high
frequency on and off signal in the test of
the conventional bucking bar is mainly due to the working pieces resonance
from the impulse after the rivet gun
fires. The impact of the rivet gun firing causes the working pieces to vibrate
at their natural frequencies. Depending
on how the work pieces are fixed, their response due to impact could be large
and the large displacement vibration
could cause the rivet head and the bucking bar to be in intermittent contact
(exhibited by 373 and in particular 373').
While using the improved bucking bar 238, the spring-back plunger is
preferably always in contact with the working
piece, on top of the bucking bar in contact with the rivet head. The
additional contact between the plunger and the
working piece can limit the working piece vibration after the rivet gun firing
through at lease one of three
mechanisms: (1) added equivalent dampening of the working piece; (2) changed
working piece boundary
conditions; and (3) increased working piece equivalent stiffness. The natural
frequency of both bucking bars is
significantly higher than any waveform signature captured; however careful
design of spring plunger system must be
practiced to ensure that this system does not have a natural frequency near
the rivet gun cycle frequency, which
would cause the spring plunger system to resonance.
Consequently, dampening from the compression spring and plunger assembly
results in: (1) increased
bucking bar stability and consequently controllability (less bouncy), and (2)
since bar 238 more quickly returns to an
anvil face contacting rivet shank steady-state condition, an ability to
increase rivet gun hammer rates, resulting in
less work hardening of the rivet material and faster rivet driving. Depending
on the rivet gun, increased air pressure
settings can result in at least faster hammering frequencies and/or higher
hammering amplitudes (such as increased
hammer force magnitude). Shorter rivet driving stages could result in a better
rivet set result because there is less
time for manual tool misalignment motions.
The falling-edge signal occurring immediately after a rivet gun "hammer"
appears to be the easiest and
most consistent portion of the various waveforms to identify. By using a low
pass Butterworth or ChevyChev or
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other filter, the switch chatter signature 371 and the contact bounce
signature 373 could be removed or reduced to
produce a "clean" (or debounced) impact signature. Hardware or software or a
combination of hardware and
software filtering are possible. Waveform detection software that serves as an
impact sensor identifies hammer
blow events during a hammering cycle and may also determine if the bucker
disengaged from the rivet during a rivet
driving cycle, resulting in an IRQ to stop the gun (reference Fig. 12, step
568).
In the embodiment tested, the solenoid took about 8 milliseconds to disable
the rivet gun. Therefore, during
a 37 millisecond hammering cycle, an optimized algorithm such as that
described in the steps above could prevent
an inadvertent hammer blow to the work 8 milliseconds prior to a next second
"hammer blow". This provides
protection for over 78 percent of a "hammer" period. Thus, by determining the
hammer period and identifying the
falling-edge-signal, system 100 could determine that anvil face 300 is in
contact with rivet shank end 70 just before
the rivet gun "hammers" again (or about 10 milliseconds before the next hammer
strike). Alternately, another
approach to prevent inadvertent hammer blows is to recognize that the rivet
gun hammer cycle period is about 37ms
with the in-contact time being about 22ms; while the solenoid closing speed is
about 8ms. In this approach, the
microprocessor ensures that there is a sufficient in-contact time interval
each hammer cycle (before each hammer
blow).
This example also demonstrated that the bucking bar system described herein
could be adapted to work
with any conventional bucking bar to roughly set rivets by counting the number
of impacts and limiting the driving
stage to a specific number of hammer blows. Although rivets would be roughly
set due to rivet-setting variables
described earlier, this method may be more consistent than previous practices
and in particular in cases of highly
unique bucking bar shapes are used to buck rivets in difficult to reach
locations. These locations are also
notoriously difficult to inspect and rework. While this not is not a preferred
embodiment of the invention, those
skilled in the art, using the teachings herein, could adapt the rivet gun to
limit the rivet driving stage to a specific
number of hammer blows to set the rivet.
This example also demonstrated that the signature shown in Fig. 22 can be used
to count hammer blows
and coupled with a hammer cycle timer also determine hammer frequency. This
embodiment allows the setting of
the maximum time limit the bucking bar can be decoupled from the rivet during
the driving stage. Exceeding this
maximum time limit would be a detection of the bucking bar anvil face being
disengaged with the rivet during the
driving stage and thus prevent inadvertent hammer blows to work not being
backed by the bucking bar. In another
preferred embodiment, system 100 alternately includes an on-circuit-board
accelerometer sensor to sense impacts
and determine hammering frequency.
it is understood from these findings that microprocessor 500 may optionally
also use measured bucking bar
tool-to-rivet contact data to automatically adjust, or otherwise recommend to
the user, the air regulator setting levels
supplied to the rivet gun by adjustment of the air regulator setting. This
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above signature forming a controlled Pulse Width Modulated (PWM) digital
signature i.e.) controlling the elapsed
time of the trough and the elapsed time of the crest of the pulse-train
signature. It is noted in the described method
that a safe time interval prior to a "hammer blow" is important but can also
be a limitation to detecting bucking bar
disengagement during a riveting stage and to the maximum safe amount of air
pressure supplied to the rivet gun.
Furthermore, upon starting a riveting project, users normally practice on test
work specimens to ensure they
have the proper air regulator setting before beginning work on aircraft
surfaces; however, should this step be
omitted, microprocessor 500 would optionally also detect anomalies in the
measured bucking bar tool-to-work
contact signature to identify grossly improper air regulator settings and to
immediately stop the rivet gun or
alternately adjust to in real time the air regulator setting thus preventing
damage to the work.
Finally to summarize, it is noted that the mechanical vibration and previously
cited switch chatter are
substantially reduced using bucking bar 238 compared to a conventional bucking
bar having similar mass. This
reduction in vibration is a result of at least one of the spindles feet
contacting the work ancUor the compressive
spring providing a dampening effect. In either case, preferred embodiments of
bucking bar 238 are more stable and
controllable when compared to conventional bucking bars of comparable mass.
Also, compared to conventional
bucking bars of similar mass, bucking bar 238 spends more time with anvil face
300 in communication with the
rivet 70. This is a demonstration of the improved performance of preferred
embodiments of bucking bar 238 over
conventional bars. This improved performance can be exploited by increasing
the rivet gun hammer frequency to
set rivets faster. Benefits of faster rivet setting include saving time,
improved rivet properties by reducing work
hardening of the rivet material resulting is stronger rivets, and improved
consistency since critical tool-position
holding time is reduced during the rivet driving stage. Alternatively, since
this improved performance results in
reduced tool vibration, the invention reduces carpal tunnel or hand-arm
vibration syndromes and other debilitating
user injuries such as white finger.
Referring to Fig. 24, a partial cross-sectional view of still another
alternate embodiment of the invention is
presented. In this embodiment, set tool assembly 640 comprising set tool 104
that conventionally attaches to rivet
gun 102 using a retaining spring (not shown) by coupling rivet gun 102, or
other type of rivet driver, into recess
1002 between first raised cylinder diameter 1004 and second raised cylinder
diameter 1006. Set tool 104 further has
reduced cylinder diameter recess 1008 to receive external spring clip 1010 and
center-line-located hole 1012 to
receive a spiral roll pin 1014. Set tool 104 further has anvil face 300 at its
distal end while shaft 325 of set tool 104
provides axial guidance to plunger 268.
Next, housing 260 is secured proximal to the shoulder of second raised
cylinder diameter 1006 by spring
clip 1010 or alternately by spring 266 and also serves to provide axial motion
guidance for plunger 268. Spring 266
pushes against said clip 1010 and/or against inside of housing 260 and also
pushes against plunger 268 at plunger
shoulder 308. A person having skill in the art will understand that the load
source force applied to plunger 268 may
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be applied by means other than a spring, such as by an air bladder. Plunger
268 is retained by pin 1014 located in
hole 1012 of set tool 104; where the ends of pin 1014 protrude into pin slots
1016 of plunger 268. Therefore, under
normal conditions, spring 266 pushes plunger 268 axially outward of housing
260) until pin 1014 stops plunger 268
with pin 1014 being disposed at a first end of slot 1016. In use, by applying
force at spindles feet 312, plunger 268
can travel axially, compressing spring 266 until pin 1014 limits or stops the
travel of pin 1014 at a second end of slot
1016. As plunger 268 travels axially, the gap height 314 between spindles feet
312 and anvil face 300 changes.
Sufficient travel of plunger 268 is provided between first and second ends of
slot 1016 to accommodate under
normal conditions a protruding rivet shank in gap height 314 and to
accommodate under rivet set conditions a
desired rivet head height in gap height 314.
Next, affixed to housing 260 via a slotted groove mate is lid 1018. Lid 1018
preferably has four-sides and
a top and has a pocket or recess therein to hold sub-assembly circuit board
1020. Sub-assembly circuit board 1020
preferably comprises multi-conductor connector jack 1022, LED 1024, spring
loaded contacting pin 1023, and
micro-switch 350 (a first sensor) that comprises switch lever arm 352. Spring
loaded contacting pin 1023 allows
electrical conductive communication from sub-assembly circuit board 1020 to
anvil face 300 via lid 1018 or via
conducting path from lid 1018 and housing 260 to anvil face 300. In this
illustration, plunger 268 is considered to
be a non-electrically-conductive material; however, those skilled in the art
will recognize other configurations are
possible such that contact of anvil face 300 to rivet shank end 70 (not shown)
can be detected by a formed loop
circuit like those previously illustrated herein using wires 220 and 226 as
presented in Fig. 8 or conducting other
paths using optical photo coupler circuits (presented later). Other possible
configurations are also presented later.
Hole 1026 in said lid 1018 allows light 1027 from LED 1024 to illuminate the
work pieces (not shown) and/or may
be used for operator communication. Sub-assembly circuit board 1020 couples to
a circuit board (not shown but
similar to circuit board 212 in Fig. 8) via a multi-conductor cable (not
shown) or alternately via a wireless
communication link.
Upon assembly, sub-assembly circuit board 1020 is preferably inserted into the
recess in lid 1018 and is
potted into place while ensuring conductive pin 1023 contacts the frame of lid
1018. Next, using a sliding motion,
lid 1018 is affixed to housing 260 via a groove male/female mate. Next,
housing 260 is installed by sliding it over
anvil face 300 of set tool 104 and is held into position by installing
external clip 1010. Next, compression spring
266 is inserted over the end of set tool 104. Finally, plunger 268 is
installed, causing some pre-compression of
spring 266 and is secured by equally spacing pin 1014 in hole 1012 so that it
retains plunger 268 by the presence of
pin 1014 in slots 1016. Those skilled in the art will recognize that there are
many ways to attach housing 260. In a
first example, rather than using external clip 1010, an internal clip may be
used by extending housing over second
raised cylinder diameter 1006 in installing an internal clip on housing 260
body proximal to recess 1002. In a
second example, body of plunger 260 may be made longer and have receiving
holes that mate with hole 1012. In
this case pin 1014 may then be lengthened to secure plunger 260.
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In this embodiment, a means for making various micro-adjustments is omitted
and the desired rivet head
height is determined by appropriately selecting component dimensions, such as
appropriately sizing the cylinder
length of plunger 268 and slot 1016 locations in plunger 268. By specifying
the length of plunger 268 and allowing
necessary the plunger travel, when gap height 314 (between anvil face 300 and
spindles feet 312) becomes
substantially equal to a desired rivet head set height 84, then switch 350
simultaneously actuates by movement of
switch lever arm 352 against plunger shoulder 308. Those skilled in the art
will recognize many ways to locate
switch 350 (a first sensor) so that the switching threshold toggles the switch
state when switch lever 352 contacts on
shoulder 308 when the gap height or distance between the anvil face and work
surface substantially matches a
desired rivet height.
In other words, in practice set tool assembly 640 is preferably designed to
set a specific rivet head size and
a multiplicity of attachable set tool assemblies 640 (or packaged kits of set
tool assemblies 640) are each
manufactured to match a desired rivet head height 84 for each specific rivet
head being formed 86 (see Fig. 3). In
practice, this approach is analogous to a conventional socket set having
multiplicity of sockets with each socket
mating with a specific bolt size. Previously described features of other
embodiments are intentionally omitted here
for clarity, such as the plunger travel detection switch 708 (see Fig. 15) or
spindles feet contact points 312', 312"
and 312" (see Fig. 16) or LED communication lights (see Fig. 8); however it
will be understood by those skilled in
the art that any of the teachings or tool features throughout this invention
may be incorporated into this tool and that
teachings or features throughout this discourse are interchangeable between
all tools without limitation--according to
the needs of the user.
Still referring to Fig. 24, in application, set tool 104 is attached to rivet
gun 102. A bucker installs a rivet
and backs the manufactured head with a bucking bar. Then, the rivet gun
operator positions set tool 104 over rivet
shank end 70, contacting spindles feet 312 on the work surface and, by
applying force, compresses spring 266 to =
slide plunger 268 axially. Contact of anvil face 300 with rivet shank end 70
is then preferably detected by a loop
circuit sensor and rivet gun 102 is enabled by coupling it to a power supply,
for example, an air supply if the rivet
driver is pneumatically powered or other type of power supply if the rivet
driver is powered other than
pneumatically. Then, the rivet driving stage commences. When the driven rivet
head height substantially equals to
desired rivet head height 84, a switch, for example switch 350 described
above, is actuated and riveting ceases by
decoupling rivet gun 102 from its air supply. Given the many teachings of this
invention, those skilled in the art will
recognize many methods for detecting when anvil face 300 contacts rivet shank
end 70. One of the preferred
methods of detecting anvil face and rivet shank end contact with tool
illustrated in Fig. 24, is via a loop circuit using
the circuit described above with wires 220 and 226 in Fig. 8, thereby using
the loop circuit as a sensor.
In an alternate embodiment a mass block (not shown in Fig. 24) is attached to
set tool 104 (similar to
attaching set tool 104 to a rivet gun). This functionally transforms the set
tool into a bucking bar and further
demonstrates that the teachings of the set tool can be applied to the bucking
bar and that both tools are the same or
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nearly the same. Those skilled in the art will recognize that a set tool or a
bucking bar may serve as a rivet shank
deforming tool. Therefore, a rivet shank deforming tool may be either a set
tool or a bucking bar.
Referring to Fig. 25, a partial cross-sectional view of still another
preferred embodiment of the invention is
presented. In this embodiment, alternative set tool assembly 1030 comprises
set tool 104 that conventionally
attaches to rivet gun 102 using a retaining spring (not shown) by coupling
rivet gun 102 into recess 1002 between
first raised cylinder diameter 1004 and second raised cylinder diameter 1006.
Set tool 104 further has recess slot
1008 to receive external spring clip 1010 and anvil face 300. In this
illustration, anvil face 300 has a concave
surface to substantially match the shape of universal manufactured rivet head
62 depicted in Fig. 2A. Compression
spring 266 applies force against clip 1010 and housing 1032 to secure housing
1032 against second raised cylinder
diameter 1006. Alternative housing 1032 has a circuit subassembly (not shown)
having optional LED 1024 to
illuminate the work pieces and optionally LED 1034 to provide communication to
the user; although optionally LED
1024 may also provide communication (serve as an indicator). The circuit
subassembly further contains a
contacting pad (not shown) or optionally spring loaded electrical contacting
pin 1023 to provide electrical
=
communication from the circuit subassembly to anvil face 300. A multi-
conductor cable 236 preferably attaches to
alternative housing 1032 and has strain relief 606. Combined with the
teachings and equipment of Fig. 8, a similar
loop circuit forms a second sensor that uses circuit board 212, wire 220, and
wire 226 is used to preferably detect
when anvil face 300 is contacting rivet head 62 (although wire 226 is
preferably replaced by multi-conductor cable
236). In preferred embodiments, this loop circuit forms a second sensor and
the microprocessor detects when this
anvil face 300 decouples from the rivet during a rivet driving stage and
determines a damage event condition; then
immediately ceasing riveting to prevent "smiley" face damage.
The circuit subassembly (not shown) couples to a circuit board (not shown) via
a multi-conductor cable 236
or alternately via a single conductor cable or via wireless communication
according to user needs. If wireless
communication is used, the circuit subassembly provides necessary wireless
equipment with microprocessor and
means for delivering power, preferably from battery source. Also, for wireless
application, any proximity sensor,
loop circuit sensor, touch-capacitance sensor, or other sensor technology may
be employed to detect the contact of
anvil face 300 with rivet head 62. Given the many teachings of this invention,
those skilled in the art will recognize
that many methods may be used for detecting when anvil face 300 contacts
either manufactured head 62 or 64, or
rivet shank end 70. This statement also applies to detecting when spindles
feet 312 of plunger 268 (see Fig. 24)
contact a first work surface 74 or a second work surface 76 (see Fig. 3).
Other preferred methods are presented later
in this disclosure.
In application, the rivet gun operator installs a rivet and places anvil face
300 of set tool 104 on rivet
manufactured head 62. Contact is detected by second sensor. The bucker then
backs rivet shank end 70 with
conventional bucking bar 52 (or the like) or optionally backs rivet shank end
70 with bucking bar disclosed herein
(e.g., one described in Figs. 7A and 7B). When the bucker uses bucking bar 52,
a master circuit board (not shown)
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coupled to alternative set tool assembly 1030 detects when tool 104 anvil face
300 contacts rivet head 62 and
enables the operation of rivet gun 102 by coupling it to its air supply. Then
the rivet driving stage commences.
During the rivet driving stage, system 100 (see Fig. 8) immediately detects if
anvil face 300 of set tool 104
substantially decouples contact with said manufactured head 62 and immediately
ceases riveting in order to prevent
smiley face damage 63 or 63' (described in Fig. 4F). If the described
decoupling above does not occur, the
operators judge the duration of said driving stage based on their skill and
art to set the rivet so that driven rivet head
86 height substantially equals desired rivet head height 84. Accidentally
decoupling of anvil face 300 from rivet
head 62 during the rivet driving stage typically occurs as a result of the
rivet gun operator not maintaining correct
forces or tool alignment relative to the rivet head 62 or to the work surface
74.
However, when the bucker uses a disclosed bucking bar with system 1030, a
circuit board detects when
both anvil face 300 of tool 104 contacts rivet head 62 and anvil face 300 of
disclosed bucking bar in contact with
rivet and then enables the operation of rivet gun 102 by coupling it to its
air supply. Then the rivet driving stage
commences. If the described decoupling above does not occur, circuit board
ceases riveting when disclosed bucking
bar sensor indicates that driven rivet head height 86 substantially matches
desired rivet head height 84. Optionally
LED communication lights on set tool 104 and the disclosed bucking bar
indicate to the operators when that rivet
gun operator is "ready", when bucker is "ready", and when the rivet driving
stage is complete. Therefore, those
skilled in the art will recognize that equipment shown in Fig. 25 used with
other equipment from other teachings
presented herein provides a means to prevent the smiley damage described in
Fig. 4F. Set tool assembly 1030 may
be optionally used with either conventional or invented bucking bars disclosed
herein.
Referring to Fig. 26, a partial cross-sectional view of still another
preferred embodiment of the invention is
presented. This illustration employs the many teachings in this discourse to
convey another preferred embodiment
of a rivet set tool assembly 1100. Here, partial assembly 1100 is depicted for
brevity to represent the working end of
either the invented bucking bar or the invented set tool because, when forming
a shop head, either tool functionally
works in a similar manner and given the teachings herein those skilled in the
art can construct the remainder of the
tool. Hammer stem 325 has hole 1012 and anvil face 300 at its distal end.
Plunger 268 has two opposing pin slots
1016 and is axially retained on hammer stem 325 by pin 1014 (not shown in this
view) which is disposed in hole
1012. Compression spring 266 applies axial force to plunger 268. In this
embodiment, housing 260 comprises at
least one lid 1018 and sub-assembly circuit board 1020 having a commutation
lever 1104 that rides on first electrical
conducting pin 1106. First electrical conducting pin 1106 is affixed to
plunger 268 and forms spindles feet 312' at
distal end of plunger 268. A plurality of first electrical conducting pins
1106 may be used to form additional
spindles feet 312" and 312" where each spindles foot is part of a unique
electrical loop circuit and can form a
plurality of fourth sensors).
Alternately, in another embodiment, a plurality of second electrical
conducting pins 1108 may be affixed
(preferably embedded, but protruding slightly) to the outside diameter of
plunger 268 so that conductive

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commutation is provided from friction contact of each second electrical
conductive pin 1108 to commutation lever
1104 or to a conductive pad (not shown) located on the inside diameter of
housing 260. Those skilled in the art will
understand that a plurality of spring pins (similar to spring loaded
electrical contacting pin 1023) may be used to
provide a plurality of spindles feet 312' to electrically define a planer or
near planer surface orthogonal to the plane
of work surface 74 while still accommodating slight contours in work surface
74 since most work pieces in aircraft
have contour shapes. Spring pin examples are exhibited at the WWW domain mill-
max.com. (This sort of pin can
also be a conducting post 256). Preferably, a plurality of first electrical
conducting pins 1106 or a plurality of second
electrical conducting pins 1108 form a plurality of spindles feet 312' and are
preferably disposed 120-degrees apart
to form first, second, and third contact points, thereby forming spindles feet
312', 312", and 312" as shown in Fig.
16.
In the illustrative embodiment shown in Fig. 26, plunger 268 is preferably
fabricated from a non-
electrically conductive material. This configuration preferably provides a
unique electrical loop circuit that is
formed (or switched) by contact of one or more spindles foot with work surface
74. For example, by allowing
spindles feet 312' to have a positive circuit electrical potential and both
spindles feet 312" and 312" to have a
negative circuit electrical potential, then when the spindles feet contact the
airframe surface, a first circuit is formed
by loop circuit closure from spindles feet 312' to 312" and a second circuit
is formed by loop circuit closure from
spindles feet 312' to 312". The first and second circuits form fourth sensors.
Furthermore, in this example, a third
circuit is formed between spindles feet 312' and anvil face 300 when anvil
face 300 contacts rivet. The third circuit
forms a second sensor. Therefore, with the loop circuits described above,
means are provided to detect contact of
one or more spindles foot with work surface 74, to detect tool alignment and
to detect when anvil face 300 contacts
rivet shank end 70 or optionally rivet head 66. Microprocessor instructions
can then poll loop circuit detection
sensors (or similar sensors) to determine when the tool contacts the work, to
determine tool orthogonal or near
orthogonal tool alignment relative to the work, and to determine when anvil
face 300 is in contact with rivet head 66
or rivet shank end 70. After said determination is made, microprocessor
instructions can then interrupt tool
operation if undesired tool alignment is determined and/or can operate
communication LEDs, like LED 240" in Fig.
16, to provide feedback to correct tool alignment. Given the teachings of this
example, those skilled in the art will
recognize numerous ways to form the described circuits so the example is not
limiting.
The configuration described above provides yet another loop circuit detection
path by eliminating wire 220
and replacing wire 226 with multi-conductor wire 236 to replicate the
described loop circuit formed using wires 220
and 226 in Fig. 8. The configuration eliminates the need for wires 220 and 226
in Fig. 26. Sub-assembly circuit
board 1020 is preferably coupled to a control circuit board by a multi-
conductor cable or by any wireless means (not
shown). Also the features of Figs. 24 and 26 could be incorporated into Fig.
25 to aid tool alignment and prevent
"smiley" type damage; yet another damage event condition. Therefore, in
addition to further illustrating the concepts
presented in Fig. 16, Fig. 26 demonstrates to those skilled in the art the
potential benefits of using selective
teachings presented in this disclosure to achieve user goals.
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Fig. 27 presents a partial cross-sectional view showing a partial assembly of
still another preferred
embodiment of the invention. Like Fig. 26, this illustration also employs many
of the teachings in this disclosure to
convey to those skilled in the art that the depicted partial assembly features
may be employed on the "working end"
of either the disclosed set tools or the disclosed bucking bar tools. In other
words, portions of alternate set tool 1100
in Fig. 27 are functionally equivalent to those shown in Fig. 26 and are again
depicted for clarity to represent the
working end of either the disclosed bucking bar or the disclosed set tool.
Given the proceeding teachings, those
skilled in the art will be able to construct the remainder of the tool. In
alternate set tool 1100, analog detector or
sensor 1120 is depicted that continuously measures linear displacement of
plunger 268 relative to anvil face 300 to
measure gap height 314 (during a rivet driving stage and when the anvil face
is in contact with the rivet shank end,
the gap height is substantially equivalent to the distance between the anvil
face and the work surface). In this
illustration, detector or sensor 1120 measures the linear travel of target
1121 material affixed in plunger 268 to
determine or measure gap height 314 between spindles feet 312 and anvil face
300.
Sensor 1120 senses distance between the work surface and the anvil face; it
serves as a first sensor when
said distance is substantially equal to a desired rivet head height. However
because it is analogue, sensor 1120 may
also serve as a third sensor when said distance is a measure of protruding
rivet shank length which allows
determination of rivet size and corresponding desired rivet head height. A
protruding rivet shank is distance 80 (See
Fig. 3). Sensor 1120 also serves to continuously measure axial travel or
displacement of the plunger relative to the
anvil face which allows determination of when this travel first stops to be a
measurement of rivet protruding shank
length (discussed later). Preferably a microprocessor uses input from a second
sensor (e.g. described earlier as loop
circuit sensors) to determine when an anvil face 300 first makes contact with
a rivet shank end, just prior to
commencing a rivet driving stage. Those skilled in the art will recognize
still more methods of anvil face and rivet
shank end detection: when urging anvil face 300 towards a work surface the
plunger 268 does not move until
spindles feet 312 come into contact with work surface. Upon further urging the
plunger 268 displaces axially and
stops (displacement motion ceases) when the anvil face first contacts the
rivet shank end; software detecting this
ceased motion may then poll sensor 1120 to determine a protruding shank
length, a rivet size and a desired driven
rivet head height; before commencing a rivet driving stage. Using this sensor
and software detection method, sensor
1120 can serve as a third sensor without first using information from a
tangible second sensor to determine as a
marker when an anvil face first makes contact with a rivet shank end. This is
because software detects when the
anvil face contacts a shank end by monitoring motion of the plunger through
continuous polling of sensor 1120 and
therefore the combination software and sensor 1120 forms another type of
second sensor.
With the above teaching, those skilled in the art will recognize that when
using software to monitor the
third sensor 1120 input signal and corresponding plunger motion, a protruding
rivet shank length may be determined
when the plunger first stops (this corresponds to a measurement between the
anvil face and work surface when the
anvil face first contacts a rivet shank end) and, therefore, a rivet size may
be determined. This is a preferred method
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of determining a rivet size when the work surface is a non-conductive
material, such as carbon fiber. Alternately, an
input from a second sensor detecting an anvil face contact with a rivet shank
end is used to signal a microprocessor
to poll third sensor 1120 and then determine a rivet size. A user input is yet
another way to provide the
microprocessor with rivet size information. Next, using input from an impact
sensor, a microprocessor can
determine the total or tally of impacts needed to set a rivet from a rivet
driving stage. Next, the microprocessor
determines by calculation or lookup table said tally of impacts to drive said
rivet approximately corresponds to said
rivet size and optionally indicates to a user a recommend air regulator
adjustment recommendation for a next rivet.
This air regulator adjustment feedback approach preferably improves rivet
properties such as fatigue strength and
minimizes rivet material work hardening caused using excessive impacts to set
a rivet. Said air regulator adjustment
recommendations are used to continuously improve the rivet set quality.
This configuration illustrates the use of other types of sensors to measure
linear travel of plunger 268 to
determine gap height 314. In a first example, sensor 1120 may be a high
resolution magnetic displacement sensor
integrated circuit paired with magnet target 1121. In a second example, sensor
1120 may be an inductive proximity
sensor paired with iron target 1121. Those skilled in the art will recognize
that other sensors and/or targets are also
possible with this configuration and that these may include without limitation
at least one of inductive, hall effect,
and magneto-resistive technologies. Furthermore, the configuration may be
modified to accommodate such sensors.
Such artisans will also recognize and incorporate sensor calibration when
necessary and understand that at least one
of the above example sensors requires that housing 260 (and particularly
sensor 1120) rotation not be permitted to
avoid rotational position changes between the sensor and the target that would
misalign the sensor/target pair and
loss of calibration or produce inaccurate linear plunger motion measurement.
Without limit, other sensor
configurations are also possible. A plurality of sensors 1120 and/or targets
1121 may be used to improve
measurement resolution. A target may also consist of a plurality of magnets
stacked together with reversing poles.
Alternatively, the body of an inductive sensor such as an LVDT sensor may be
affixed to housing 260 while the
sensor's plunger could be in contact with or affixed to the plunger 268_
Likewise those skilled in the art will
recognize the application of capacitive, eddy current, magneto-inductive, draw-
wire, confocal or other sensors for
measuring relative displacement, distance or position between the housing 260
and the plunger 268 to determine a
corresponding off-set distance between the anvil face and the work surface.
Therefore, using the above teachings, just before commencing a rivet driving
stage and when a described
second sensor detects first contact of anvil face 300 with a rivet shank end
70, microprocessor 500 immediately
measures and stores into memory the length of protruding shank 80 from work
surface 76. (Measuring a protruding
shank length is another method of determining a rivet size and a desired rivet
head height). Then, microprocessor
500 calculates or otherwise uses a look-up table (also stored in
microprocessor memory 504) to determine the
optimal or desired rivet set head height 84. This ensures that all rivet heads
are set to substantially match a desired
set rivet head height 84. Optionally, previously described LED lights 214,240
may be used to indicate to operators
when anvil face 30 first makes contact with either rivet manufactured head 66
or with rivet shank end 70. Also,
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since measuring protruding rivet shank length and rivet driving stage use the
same tool in the same mechanical
motion, system 100 can determine the achievement of a desired rivet head
height and set a rivet faster than
conventional methods that require a plurality of robotic motions to achieve
this result. Therefore, the teachings of
Fig. 26 and 27 may be incorporated into the working end of fully robotic
machines to set rivets at a faster rate.
To further clarify, preferably in the embodiment illustrated in Fig. 27 when
analog sensors are used, a
measurement of protruding rivet shank length is made by storing gap height 314
value when anvil face 300 first
contacts rivet shank end 70. This is a measure of protruding shank length and
corresponds to a rivet size. Then, with
rivet size information the microprocessor 500 uses a lookup table or
alternately calculates desired set rivet head
height 84 and stores this value into a first memory. Finally, during the rivet
driving stage, the measured forming
rivet head height is continuously updated into a second memory and when the
said forming rivet head height is
substantially equal to a desired set rivet head height 84, stored in the first
memory, riveting is ceased. In other
words, the measured rivet height of the forming rivet head is continuously
stored in the second memory and
repeatedly compared to desired set rivet head height 84 in first memory and
riveting is ceased when these values
substantially match.
As previously indicated, after measurement of a protruding shank length (a
measure of rivet size) this
disclosure also allows for rivet property assessment. Assessment may include
rivet material strength based on
number of impacts required to achieve a desired rivet head height or may
include to precise control of a set rivet by
closely matching it a desired rivet head height; this also controls the
location of the rivet material strength on a
stress-strain curve to optimize rivet set strength and rivet fatigue strength
(this are rivet properties). Any means of
feedback is permitted to adjust or recommend adjustment of air regulator
settings is possible.
Also as previously indicated, the tools provided in this disclosure may be
automatically recalibrated by
tracking the number of rivets that have been set and then invoking a
recalibration test when the rivet number
substantially reaches a predetermined number of rivets. In addition, a
recalibration procedure can also include an
offset determination step where a measure of how close the tool was to a
desired calibration distance (at the
beginning of a recalibration process) is assessed. In other words an offset
distance is a measure of how far out of
calibration a first sensor is at the beginning of a re-calibration procedure.
If there is no offset distance (or it is very
small) the tool is determined to closely match a desired calibration and
either not require recalibration or be slightly
out of calibration. On the other hand if there is an offset distance (and
particularly if it is large i.e. large enough to
set rivets outside specification limits) the tool is determined to not only to
be out of calibration, but may also need to
be refurbished or replaced. For example, a control subsystem is operative to
determine an offset distance and notify
said user of said offset distance, said offset distance being a difference
between a first measure and a second
measure, said first measure being indicated by said first sensor when a first
known distance is sensed between the
work surface and the anvil face before a recalibration of the rivet driver and
said second measure being indicated by
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said first sensor when a first known distance is sensed between the work
surface and the anvil face upon a
recalibration of the rivet driver.
Therefore if the offset distance is determined to be large then the tool
likely has been setting rivets to
incorrect tolerances prior to the re-calibration checking process. Because
rivets are manufactured in various sizes
and are used to fasten materials of various thicknesses, the measured
protruding shank length will vary; therefore the
term "large" related to offset distance is a relative measure determined by
those skilled in the art but is generally to
be understood as an offset value that is unacceptable because it could produce
rivets outside specification limits
based on the rivet being set. To prevent this from happening, the
predetermined number of rivets that initiated the re-
calibration checking process can be automatically reduced. Alternately if the
tool is outside acceptable re-calibration
parameters, there is likely a component failure (such as a sensor failure) or
part wear and the tool may be flagged to
be removed from service including being refurbished or replaced. When
determining an offset distance, a first
measure is a reading of the first sensor when the gap height or distance
between the anvil face and work surface is
known. A second measure is a reading of the sensor after it has been
calibrated to match the known distance
between the anvil face and the work surface. Finally the difference between
the first measure and the second
measure is the offset distance.
Although feedback control has been presented throughout this disclosure, those
skilled in the art will
recognize that feedforward predictive control strategies can also be used to
determine when a forming rivet head
height will substantially match a desired rivet head height. For example by
plotting the deforming height of a rivet
shank end during the rivet driving stage a deformation curve showing forming
rivet head height and number of
impacts can be produced. Those skilled in the art will recognize a plurality
of real-time or near real-time analysis
methods to determine when a deformation curve will intercept a desired rivet
head height and then cease the rivet
driving stage. It is understood then that feedforward control may use
deformation rate characteristics to determine
when the deformation curve intercepts a desired optimal set-point before
ceasing riveting. The approach has the
potential advantage of eliminating a final rivet driver impact that would set
the rivet head height slightly lower than
an optimal location (even without feedforward control, the rivet would still
be set within specifications).
Those skilled in the art will recognize that a rivet shank deforms more near
the beginning of rivet driving
stage and less near the end of the rivet driving stage due to material work
hardening. This characteristic provides yet
another alternate way to determine when a driven rivet head substantially
matches a desired rivet head height. In a
first example, a microprocessor monitoring a first analogue sensor can
determine the slope (or near instantaneous
slope) of a rivet deformation curve to determine approximately when a driven
rivet head matches a desired rivet
head height. In this case the slope is negative and a relatively high scalar
value (magnitude) at the beginning of the
rivet driving stage and becomes negative and a relatively low scalar near the
end of the rivet driving stage. Relative
rate of changes in slope or values of slope compared from beginning to near
end of the rivet driving stage can be
used to assess and determine when a driven rivet head height substantially
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Likewise in a second example, a microprocessor monitoring a first analogue
sensor can determine the
amount of rivet shank deformation (or change in protruding rivet shank height)
while a rivet undergoes deformation
to determine approximately when a driven rivet head matches a desired rivet
head height. In this case the
deformation magnitude is relatively large at the beginning of the rivet
driving stage and comparatively small near
the end of the rivet driving stage. Relative rivet shank deformation amounts
(per hammer blow) are another way of
expressing a rivet deformation curve to assess shank deformation magnitudes
from beginning to near end of the rivet
driving stage to determine when a driven rivet head height substantially
matches a desired rivet head height.
Furthermore, the applicant also recognizes that by assessing near real-time
rivet setting parameters such as
rate or magnitude of slope or rivet size changes, it may be also possible to
determine a rivet size and thus a desired
rivet head height. However, because the number of impacts quantitatively
relates to the shank deformation (the rate
or magnitude of shank slope change or the rate or magnitude of shank
deformation change), these examples are
considered to be the same approach as limiting the number of impacts during a
rivet driving stage, based on rivet
size (presented earlier). These examples illustrate how measuring and
assessing plastic deformation of a rivet shank
can be used as an alternative means for sensing when a rivet has been set to a
desired rivet head height. These
examples are not limiting, for example plastic deformation could be assessed
by a high frequency anvil signature
resulting from an impact or by other means for sensing.
Referring again to Fig. 27, in an alternate embodiment a user has an input
device to provide the
microprocessor with data related to a rivet size being driven. This data may
be in the form of a manufacturer's
specified rivet size or a protruding shank length. Upon receiving this input
from the user, the microprocessor then
determines a desired rivet head height. Furthermore, to provide calibration
functionality, a user can set the distance
between a work surface and an anvil face to a known distance and then so input
said known distance into said
microprocessor.
Figure 28 illustrates a schematic drawing of an illustrative embodiment of the
firmware to operate tools
provided in the previous teachings. Schematic drawing 1150 includes a power
supply block 1152 comprising an
AC/DC power converter (utility power supply not shown) and alternately a
battery power supply. A voltage
regulator supplies desired voltage source (designated VCC) and a current
regulator supplies desired current source.
A plurality of voltage or current regulators may be used to achieve design
goals. Microprocessor 500 operates in
accordance with microprocessor instructions and has a plurality of digital
input output channels (for purposes of
simplicity the microprocessor shown does not show in-system programming or
additional input/output ports needed
to handle all channels presented). Next, control block 1154 depicts a direct
current powered solenoid valve
controlled by a field effect transistor from a microprocessor output channel
(other power supply and circuit
configurations are possible). Next, in light control block 1056, LED 1024 is
operative to be an indicator to a user
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and is operated by a transistor using an output channel from the
microprocessor 500 to control LED 1024 lumen
output or the on or off state.
Switch 350 is a first sensor and is used to detect when forming rivet head
becomes substantially equal to
desired rivet head height. Said switch 350 is coupled to a microprocessor
input channel. However it is understood by
those skilled in the art using teachings of Fig. 9 that analogue LVDT sensor
or of Fig. 27 depicting analogue sensor
1120 and target 1121 pair or (any analogue sensor) can alternately be
substituted for switch 350; in this case an
analogue to digital integrated circuit would be employed prior to coupling to
microprocessor input channels.
Next, signal control block 1058 uses microprocessor digital output channels
and transistors to supply
positive potential power according to microprocessor instructions to spindles
feet 312', 312" and/or 312". Output
signal control block 1058 follows microprocessor instructions allowing the
microprocessor digital output channels to
switch power supply via transistors to any one of spindles feet 312', 312",
and 312". These components include
transistors and as needed resistors and diodes. This allows the microprocessor
to preferably provide power in a
sequential step-wise process to any of the spindles feet and is useful because
not all spindles feet are necessarily in
simultaneous contact with an airframe work surfaces 74 or 76 (a work surface
may have a convex or concave
shape). Alternately power could also be provided to the anvil face and a loop
circuit sensor formed through at least
one of the spindles feet, but this is less preferred because upon use the
spindles feet preferably come in contact with
a conductive material (airframe) before anvil face comes into contact with a
conductive material (rivet).
In contact sensor 1060 block, the microprocessor digital input channels are
preferably coupled to said
spindles feet 312', 312", 312" and to anvil face 300 (as described in Figs. 16
and 26) via a multiplicity of optical
photocouplers. Preferably photocoupler integrated circuits are sensors for the
microprocessor when loop circuits are
closed (made). Said microprocessor 500 digital output channels in signal
control block 1058 preferably work in
conjunction with said digital input channels in contact sensor 1060 block;
optionally rapidly switching power in a
repeating cycle to at least one of the spindles feet allows same-time
detection on at least one of the other spindles
feet and/or anvil face. Since said spindles feet are also coupled to signal
control block 1058, microprocessor
instructions are used to track the spindles feet being supplied with a signal
output from signal control block 1058 to
avoid negative or false detection of said spindles feet contact. Photocouplers
coupled to spindles feet 312', 312" and
312" serve as fourth sensors to determine spindles feet contact with work
surface. A photocoupler coupled to anvil
face 300 is a second sensor used to determine when an anvil face contacts a
rivet shank end or alternately a rivet
manufactured head.
Interface loop circuit sensor block 1062 couples the microprocessor 500 to
alligator clips 1066 and 1068
forming a second sensor. Alligator clip 1068 corresponds to a digital output
channel and alligator clip 1066
corresponds to a digital input channel. In a first example use, said clip 1068
can be coupled to a set tool while said
clip 1066 can be coupled to a work surface to form a loop circuit sensor path
capable of detecting when a set tool
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anvil face contacts a rivet in said work. In a second example use, said clip
1068 can be coupled to a bucking bar
anvil while said clip 1066 can be coupled to a work surface to form a loop
circuit sensor capable of detecting when a
bucking bar anvil face contacts said rivet in said work. In a third example
use, said clip 1068 can be used with
photo-coupler input 300 to from a loop circuit sensor path to detect anvil
face contact with a rivet. Alligator clips
1066 and 1068 are similar to lead wires 220 and 226 in Fig. 8 and provide an
alternative loop circuit path to having
spindles feet contacts described in Figs. 16 and 26. Next, indicator block
1063 preferably provides a plurality of
LED indicators to provide a user with information about tool alignment
according to spindles feet contact with work
surface. Indicator block 1063 shows three LED lights, corresponding to those
depicted in Fig. 16.
Finally in Fig. 28, user interface block 1064 depicts a multiplicity of switch
state settings and a LED
indicator to form a user input/output device. Although preferably tip switch
detectors in jack plug connects (not
shown in drawing) would be used to determine peripheral equipment coupled to
the schematic 1150; however
alternately, said switch settings of said block 1064 allows users to inform
said microprocessor the mode of operation
(and consequently what software subroutines to operate) according to the
peripheral equipment connected to
schematic drawing 1150. The LED in interface block 1064 is capable of
providing an operator with mode selection
feedback in the form of unique flashing light signals.
Figs. 29A and 29B present a schematic process flow diagram for software
instructions in accordance with a
preferred embodiment of the invention illustrated in Figs. 24 through 27. The
flow diagram provides a broad =
structural framework describing software functionality which, based on the
equipment configuration and knowledge
of those skilled in the art, may be modified to suite specific needs of the
user and accommodate the operation of the
tools presented throughout this disclosure. Details of this flow diagram are
omitted intentionally for purposes of
clarity and brevity and also because it is understood that those skilled in
the art can configure software to match the
function of the tools using these teachings perhaps also with the flow diagram
teachings in Figs. 12 and 19.
Referring to Fig. 29A, in Step 1, the program starts. In Step 2, the program
initializes program settings.
Step 3 is the main program and may include the following tasks:
= Step 3a calls a subroutine to determine the mode of operation
= Step 3b calls a subroutine to calibrate the tool; this subroutine may be
configured to be called
periodically to ensure the tool is recalibrated on a routine basis, e.g.,
after setting a specific
number of rivets.
= Step 3c calls a subroutine to set the rivet according to the mode
determined in the Step 4
subroutine.
= Step 3d provides fault notification to user, e.g., if a mode of operation
could not be determined, a
fault is generated to inform the user that the microprocessor could not detect
the equipment being
used and determine the desired operation mode.
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= Step 3e restarts the main program, e.g., after each rivet setting cycle.
Step 4 is a subroutine to determine the operation mode. The purpose of
determining a desired operation
mode is to run the correct software based the tools being used and the desired
work to be performed. For example,
forward riveting tools shown in Figs. 7A and 7B using the configuration shown
in Fig. 8, or tools shown in Figs. 9,
13, 15, or 16, or the configuration shown in Fig. 20 all need to be identified
to run the appropriate forward rivet
setting software. Back riveting tools depicted in Figs. 14 and 24 follow a
different sequence of operations that
requires a different software code. The forward setting tool of Fig. 25 also
requires a unique software code.
Furthermore, the tool equipment depicted in Figs. 26 and 27 also require
unique software code. Some tools may be
equipped only with LEDs for communication, and tool combinations may be used,
such as the set tool depicted in
Fig. 25 in conjunction with a bucking bar tool depicted in Fig. 26 or 27. Due
to these numerous tools and tool
combinations, for purposes of brevity while still providing sufficient
teachings to those skilled in the art, only
selected modes of operation described in Steps 4a (Mode A with the Fig. 24 set
tool) and 4f (defined here using the
Fig. 25 set tool and Fig. 26 and 27 bucking bar tool) are presented later in
the rivet set subroutines disclosed herein.
Step 5 is a subroutine for tool calibration. Upon the initialization Step 2,
this subroutine is configured to be
CALLED the first time the tool is used and then periodically for recalibration
after a predetermined number of rivets
have been set. Rivet counting logic is included to keep track of the number of
rivets set. A two-point tool
calibration process is preferably used according to those skilled in the art
and communication LEDs, normally used
to indicate the stage of the rivet driving process, may be used for feedback
to operators to guide them through the
calibration process. Calibration is also considered to be understood by those
skilled in the art.
Step 6 is a subroutine to set rivets when Mode A was determined in Step 4.
Again due to these numerous
tools and tool combinations, and for purposes of brevity while still providing
sufficient teachings to those skilled in
the art, Step 6 describes the process flow for using the set tool described in
Fig. 24 with a flush rivet and a standard
bucking bar like prior art Fig. IA. Therefore, the equipment includes: Fig. 8
circuit board assembly 212, wire 220, a
multi-conductor cable 236 coupling said assembly 212 to the Fig. 24 set tool
(replacing wire 226 in Fig. 8), wires
232, and solenoid 112. In operation, the rivet is set as follows:
= In Step 6a, flags are cleared and LEDs are turned on to illuminate the
work;
= In Step 6b, the bucker inserts a rivet into a hole and backs it with a
conventional or prior art
bucking bar on a manufactured flush head. Then, the software detects when Fig.
24 set tool anvil
face first contacts rivet shank end and enables the rivet gun by coupling it
to an air supply by
solenoid actuation;
= In Step 6c, the height of driven rivet head is continuously measured and
stored into a second
memory and compared to a desired rivet head height stored in a first memory to
determine when
the driven rivet head height substantially equals a desired rivet head height.
When the
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determination is made, riveting is ceased and preferably a short timing delay
is used to allow the
rivet gun operator to fully decouple from the rivet before allowing a next
rivet setting cycle to
begin;
= Also in Step 6c, preferably rivet set anvil face contact with the rivet
shank end is also monitored to
determine if these surfaces become substantially decoupled (breaking loop
circuit sensor) during
the rivet driving stage because this condition could indicate that the rivet
gun operator has
prematurely removed the rivet gun from the rivet before the desired rivet set
has been achieved. If
decoupling is determined, riveting is ceased and LEDs are used to indicate the
error to the
operator. This allows corrective action.
= At end of Step 6, control is returned to the main program.
Referring to Fig. 29B (which is a continuation of Fig. 29A), Step 7 is a
subroutine to set rivets when Mode
D was determined in Step 4. Again, due to the numerous disclosed tools and
tool combinations, for purposes of
brevity while still providing sufficient teachings to those skilled in the
art, Step 7 describes the process flow for
using the set tool described in Fig. 25 with a bucking bar having features
described in Figs. 26 and 27.
Communication between circuit board 212 and bucking bar is RF and multi-
conductor cable 236 replaces wire 226.
Wire 220 is also used to form a loop circuit sensor to detect when the set
tool anvil face is in contact with the
universal manufactured head of the rivet. In operation, the rivet is set as
follows:
= In Step 7a, flags are cleared and the LEDs are turned on to illuminate
the work;
= In Step 7b, the rivet gun operator inserts a rivet into a hole and places
the rivet set tool (Fig. 25) on
the rivet universal head. Then this action is detected by make of loop circuit
sensor formed by
conductor in cable 236, set tool, anvil face, rivet, work, and wire 220 and
then momentarily LEDs
flash to indicate that the rivet gun operator is "ready";
= In Step 7c, bucker then applies a bucking bar (including features
illustrated in Fig. 26 and 27).
Bucking bar anvil face contact with the rivet shank end is detected by a loop
circuit through
spindles feet 312', the work, the rivet, the anvil face, and the hammer stem;
then, the protruding
rivet shank length is immediately measured and stored into first
microprocessor memory. Then, a
microprocessor calculates or otherwise uses look-up table to determine desired
rivet set head
height 84 which is stored into second microprocessor memory. Finally, LEDs
flash again to
indicate that both operators are "ready";
Step 7d is the rivet driving stage. Here, the rivet gun is enabled by coupling
the air supply to the rivet gun
using a solenoid valve. Throughout the rivet driving stage, at least one
software loop continually monitors
equipment to determine if the rivet has been set or if either the rivet gun
operator or bucker operator disengaged
from the rivet during the rivet driving stage. It is understood that if the
rivet set tool anvil face substantially
decouples from the rivet manufactured head; riveting is immediately ceased and
LED lights indicate the fault type to

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inform the operators about what happened and to restart the riveting process
on the same rivet. This fault detection
serves to prevent smiley damage caused by the set tool anvil face (illustrated
in Fig. 40. It is further understood that
as its name indicates, the bucking bar anvil face literally bounces on the
forming rivet head (as illustrated in Figs. 22
and 23). However, if the bucker were to remove the bucking bar during the
rivet driving stage, monitoring in Step
7d quickly detects this tool-removal type of decoupling from the bouncing type
of decoupling illustrated in Fig. 22
and immediately ceases riveting and similarly LED lights indicate the fault
type to inform the operators about what
happened and to restart the riveting process on the same rivet. Flow charts
are used in this specification to broadly
describe system operation; however, they should not be considered limiting.
Also text further augmenting the
flowcharts should be considered to be included with flowcharts when
applicable.
A person having ordinary skill in the art would understand that the invention
has applications in all types of
riveting operations. Applications include aircraft manufacture, recreational
trailer manufacture; commercial
semitrailer manufacture, boat manufacture and other riveting operations. Other
sensors may be incorporated into
system 100, including microstrain miniature contact and non-contact sensors,
e.g., available at WWW domain
microstrain.com. This invention could be incorporated into other machines
without limitation.
This disclosure describes circuit boards in many forms including master
circuit board and circuit board
subassembly. It is understood that descriptions of circuit boards was to
simplify the invention for teaching purposes
and that these descriptions should not be limiting. Also, in many instances,
wires were used for communication
where wireless communication is also possible. Furthermore, the power supply
used to impart rivet deforming
energy may be an air supply if the rivet driver is pneumatically powered or
other type of power supply if the rivet
driver is powered other than pneumatically. Also, although this disclosure
provides means for detecting when a
deforming rivet shank substantially matches a desired rivet head height and
then ceases riveting, preferably, the
desired rivet head height lies within a desired range of manufacturing
specifications or tolerances (between upper
and lower specification limits); however, using the teachings of this
disclosure--more preferably the desired rivet
head height may have significantly tighter specifications than is otherwise
conventionally achievable with prior art
manually operated equipment. Those skilled in the art will recognize that the
disclosure is for illustration and
teaching purposes and is not limiting.
Many variations of the invention will occur to those skilled in the art. Some
variations include hard wired
variations and others call for wireless variations. Other variations call for
forward riveting and others call for back
riveting. Still other variations serve to eliminate damage event conditions
caused to the rivet manufactured head by
the set tool anvil face. Variations further include controlling air pressure
and air flow and reporting the
manufacturing progress to a central computer. All such variations are intended
to be within the scope and spirit of
the invention.
81

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Although some embodiments are shown to include certain features, the applicant
specifically contemplates
that any feature disclosed herein may be used together or in combination with
any other feature on any embodiment
of the invention. It is also contemplated that any feature may be specifically
excluded from any embodiment of the
invention.
82

Representative Drawing