Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF TH INVENTION
The present invention is directed to method
and apparatus for use in application of rubber
ribbon material for the formation of tire tread on
a substrate such as a tire carcass. More particu-
larly, the present inventlon is directed to method
and apparatus employed in con~unction with a tire
building machine such as shown and described in
U.S. patent-3~177,19~ enabling the deposition
of elastomeric material upon a substrate in a
controlled fashion in accordance with a predefined
tread profile. In carrying out the invention, a
programmed is employed having principally; a
micro-computer, a floppy disk and a keyboard.
By means of the present invention, it becomes
possible to utllize current micro-processor technology
enabling readily attainable changes to a finished
tread profile by associated software modifications
rather then hardware changes.
In the past, other systems known to the appli-
cant, for example, U.S. patent 3,308,000 have been
employed for controlling the applicat~on of the
elastomeric material to a substrate. In this ar-
rangement a tire tread winding apparatus employs
a mechanically controlled arrang2ment for applying
elastomeric ribbon to a tire casing. However, the
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appr~ach disclosed in this prior art is purely
mechanical and employs a mechanical programmer and
associated spin revolution counter.
Also familiar to the applicant is U.S. Patent
3,843,~82 which is directed to a tire tread winding
machine employing a tape for controlling the amount
of spin of the rubber ribbon applicator assembly and
also the amount of azimuth displacement for ribbon
thickness control.
Other patents known to applicant further il-
lustrate well known approaches for controlling
the movement of a tire tread programmer. ~owever,
in no instance has the prior ar~ defined a com-
bination in which the use of an interface with a
tresd application apparatus is such, that the in-
stantaneous tire sp~n rotational position forms
the basis of a series of digital commands enabling
extremely precise digitally controlled simultaneous
transverse motion of the tire.
The prior systems have employed apparatus for
tread application which have utilized additional
variables of time, tire rotation velocity, or template
sensing. By eliminating these variabl~s 7 errors
as~ociated in their measurement and control hava
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been eliminated. The present invent~on provides
tire transverse position control directly as a programmed
function of tire rotational position.
SUMMARY OF THE INVENTION
The main object of the present invention is
to overcome the defects of the prior art.
A further object of the present invention is
to provide a method and apparatus by which a predefined
program forms a specific tread profile upon a tire
carcass and governs the transverse movement of the
tread material a8 it is applied.
A further object of the present invention is
to provide a method and apparatus by which the tire
rotation position is monitored during tread material
application, ~o that the displacement between
rotational pos~tion and transverse position of the tire
carcass forms a discrete relationship for governing
the tread material profile.
Additional objects and advantages of the
present invention will be more readily understood
with reference to the accompanying specificat~on,
claims and drawings.
It follows that the use of an interface emDloying
a micro-computer programmer for a tread application
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apparatus represents a new and novel approach for
controlling the profile of tread materisl as is
applied upon a substrate.
Generally, in accordance with the present
invention, the micro-computer programmer is lnter-
faced with the tire building machine and provides a
basis by which the tread ribbon applicator and tire
carcass mounting assembly are governed in order to
enable ~he application of extruded ribbon in synchron-
ization with the position of the tire about its spin
axis. This i3 accomplished by interfacing a micro-
computer programmer with the applicator assembly of
the tire building machine through a D.C. stepper
motor employed to drive the applicator assembly
and control its posltion with respect to the tire
carcass as it rotates during tread material application.
The principal features of the present invention
are directed to an apparatus employed in the formation
of a tire tread profile upon a tire surface by
supplying elastomeric tread material upon a rotating
tire carcass mounted upon a tire rotation assembly.
The tire is rotated by a conventional motor and a
stepper motor is employed to incrementally advance
the rotating tire in a transverse direction during
tread formation. The tire rotation assembly motor
ln turn is connected to a tire rotation monitor for
monitoring the .nc.emental angular displacement of
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the tire during rotation. A control assembly
defined by a micro-computer is disposed intermediate
the rotation monitor and the stepper motor, whereby
the micro-computer computes respective output signals
for governing the stepper motor to control tire
tread profile build-up in accordance with a pre-
defined program stored in the micro-c~mputer.
Also within the scope of the present invention
is a method of controlling the formation o~ a tread
profile upon a rotating tire surface, by the appli-
cation of elastomeric tread mat~r~al as the tire
surface is urged to traverse a def m ed course of
travel. A tire profile program in the form o~ a
series of tire profile segments is introduced into
a micro-computer that is responsive to t~re move-
ment duri~g tread profile formation. Thereaft~r,
increments o~ the rotating tire are measured and
incremental motiun imparted in the transverse
direction to the rotating tire. Electrical input
signals measuring the circumferential angular dis-
placement increments o~ the rotating tire are trans-
mitted into the micro-compu~er and in turn a series
- of output signals are transmitted by ~he mlcro-
computer for imparting incremental motion to the
tire, as a function o~ the ~ire profile segments.
Lastly, the angular displacemen~ input signals are
counted and compared to the programmed segment length
with a next program segment being then introduced
nto the micro-computsr when the coun~s ar~ equal.
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According to a further broad aspect of the present
invention, there is provided an apparatus having an application
assembly providing elastomeric tread material, a rotation
assembly driven by motor means mounting and rotating a tire
carcass and incremental drive means disposed in working
relation to said application and rotation assemblies for moving
one of said assemblies in a transverse direction relative to
the other for the formation of a tire tread profile in accord-
ance with a predefined program by selectively winding the
tread material on the rotating tire carcass, control means
comprising:
tire rotation monitoring means connected to said
motor means for monitoring the incremental angular displacement
of the tire carcass and providing signals representing discrete
increments of each revolution of tire carcass rotation; and
micro-computer means iwith stored programs having
means for selecting a predefined one of said stored programs
and being connected to said monitoring means for receiving said
representative signals therefrom,
said micro-computer means producing control signals
in response to said representative signals in accordance with
said predefined one of said stored programs and being connected
to provide the control signals to said incremental drive means;
and
said control signals resulting from computed ratios
defined by the relative positions of said application assembly
to the tire carcass and the rotational positions of the tire
carcass.
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According to a further broad aspect of the present
invention, there is provided a method of controlling the
formation of a tread profile upon a rotating carcass by the
selective application of elastomeric tread material while
the rotating tire carcass is caused to traverse a controlled
transverse course of travel in response to programming means,
including the steps of:
introducing a tire profile program having a series
of profile segments into a micro-computer means responsive
0 to signals resulting from tire carcass rotation,
monitoring the incremental angular displacement of
the rotating tire carcass and providing input signals to said
micro-computer means representing discrete increments of each
revolution of tire carcass rotation'
summing the input signals for selection of the
appropriate profile program segment and providing output
signals in response to the input signal in accordance with
the selected profile segment, and
incrementally moving the rotating ~tire carcass
0 along the transverse course in response to the output signals.
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IN THE DRAI~JINGS
Fig. 1 is a front elevational view of the
present invention employing a rubber tread material
applicator assembly and a tire carcass rotational
assembly ~or the placement of tread material upon
a tire carcass.
Fig. 2 is a block-diagram o~ the micro-computer
o~ the in~ention together with ma~or ~nput - output
devices.
DESCRIPTION_OF PREFERRED EMBODIMENT
In accordance with the opexation of the invention,
the basic tire building machine eonsisting of the
tread applicator assembly 11, machine frame 12 and
the carcass manufacturing assembly 7 are of the type
described and disclosed in U.S. Patent 3,177, 918.
The re~erence numerals in this application do not
necessarily correspond to those of the aforementioned
patent.
As shown in Fig. 1, a micro-computer 1 is em-
ployed and fo~s part o~ the total apparatus 2. In
op~ration, the micro-computer 1 accepts rotation
position si~nals Erom a digital encoder 3 which is
directl~- coupled to the tire carcass spin drive
motor 8. The signals have the form of a series of
electrical pulses which are a direct ~uncti~n of
the circumferential position o~ tire carcass 4
about its spin axis.
The micro-computer 1 employs previou~ly stored tread
profile data and relates that to the input pulses
in order to control the transverse position of the
tîre carca~s 4. These outp~t signals take the form
of fl series of electrical pulses transmitted to a
D.C. stepper motor 5 through a stepper drive assembly
6. The D.C. stepper motor 5 and associated drive
assembly 6 form a system which txanslates electrical
pulses into discrete angular position increments of
the ste~per motor S to ultlmately govern and provide
motive power for the transverse motion of the tire
carcass assembly 7.
The block diagram in Fig. 2 illustrates the
micro-computer 1 and associated hardware. An operator
display and control panel 9 contains an array of push
button switch actuators 10 (Fig. 1) and LED displays
13 (Fig. 1) for controlling and monitoring: the tread
applicator assembly 11, (Fig. 1) the carcass mounting
assembly 7, and the operation of placing tread material
14 upon a tire carcass 4 under program control.
The operator display and control panel 9 is
connected to the central processing unit 15 provided
with a commercially available micro-processor unit
such as Motorola MC6800 as shown in the "Motorola ~68G0
Micro-computer System Design Data Manual" published in
197~ by Motorola Inc.; Phoenix, Arizona. An on-line
memory sub system 16 is connected to the central
processing unit 15. In operation the on-line memory
sub-system 16 contains all necessary program data to
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operate the inventive apparatus 2 and control the
relative positions of the tire carcass 4 and the
tread application assembly 11. The central processing
unit 15 provides the necessary program steps to execute
the instructions contained in the on-line memory sub-
system 16. The on-line memory sub-system 16 employed
herein can be o the type composed of such commercially
available components as - Motorols MCM 6810A X 8
Bit Static Random Access Memory shown and described
on page 111 of the "M6800 Micro-computer System Design
Data Manual", published in 1976, by Motorola Inc.;
Phoenix, Arizonia.
An off-line memory sub-system 17 contains all
of the active and non-active machine logic coding as
well as, all tire profile programs as stored by the
operator and entered through a keyboard 18 of.the
type such as~ commercially available Grayhill kcyboard
shown and described in Bulletin 2~2, Published in 197
by Grayhill Inc.; La Grange, Illinois. The off-line
memory sub-system 17 employs a floppy disk drive, such
as commercially available CalCcmp 140 Floppy Disk
Drive Shown and in "140 Floppy Disk Drive OEM Reference
Manual", published in 1974 by California Computer Products
Inc.; Anaheim, California.
GENERAL DESCRIPTION OF THE MICRO-COMPUTER
A specifically developed program is employed
after the neces~ary tread profile data and its
relationship to the apparatus are obtained from
calculated data. This informa~ion, in turn, is entered
directly into the micro-computer l through use of a
keyboard 18. It follows that each program can be
permanently stored and, in turn retrieved by operator
action as will be explained hereinafter. Likewise9
corrections or subsequent modifications can be
easily and simply keyed in and stored; and a modified
program can replace or supplement the original program.
The actual structure defining the micro-computer l
includes a series of sub--systems ~see Fig.2) which are
electrical in nature and are connected to an operator
display and control panel 9 provided with a series of
push button switch actuators 10 (see Fig. l) for
controlling the inventive apparatus 2. For an example,
the tread applicator assembly 11 can be controlled to
travel manually towards the left or right direction
respectively or to a designated "home" position through
appropriate push button switch actuators 10. The
initial position of the tread applicator assembly 11
prior to starting the tire program is arrived at
through a program reset function which has been
previously calculated to define the start locat~on.
A given tire profile program is retreived from the
off line memory 17 by appropriately selecting a
predefined designation number on thumb wheel switch
20 and energizing a program load switch 21.
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More specifically, the micro-computer 1 i9 provided
with a series of displays, i.e., L.E.D. displays 13,
for monitoring the tire profile program parameters.
A program display 19 indicateS the current tire
program number in on-line memory 16. Additional L.E.D.
displsys show parameters as: program segment or location,
the number of tire revolutions in a particular segment
of caslng build-up, and the surface length of tread
applicator travel for a given segment.
During opera~ion, programs which are internally
stored by the micro-computer lon its off line memory
17 are "read" by dialing-in a designated program
identification number on thumb wheel switch 20.
The stored program is then recalled from memory by
actuating program load switch 21 and placed in readiness
to run. Programs can be visually verified since all
values are nwmerically displayed on a series of light
emitting diode (LED) displays 13, 19.
MICRO-COMPU~ER ~JNCTION FO~ TREAD PROFILE FOR~TION
In operation, as the tire carcass spin drive
motor 8 i8 actuated, a commercially available digital
encoder 3 transmits a ~eries of electrical pulses to
the micro-computer 1. These pulses are a direc~ and
continuous function of tire carcass rotational position
about its spin axis, namely, the axis about which the
tire rotates circumferentally during tread material
application. More particularly pulses have the
characteristics of discrete electrical signals describing
extremely small increments of aforesaid tire rotation.
OtiJ
In accordance with a predefined pro~ram, the micro-
computer 1 calculates a ratio which reflects the
required t_ead profile for a given tread profile
segment. As used herein, a tire profile segment is
intended to mean a geometrical portion of a tire tread
profile definable by a fixed and constant relationship
between the relative displacements of tire spin and
tire transverse motions over a defined length along
the transverse line of motion. The output signal
of the micro-computer 1 takeq the form of an electrical
pulse txansmitted by the micro-computer 1 to the
stepper motor 5 through the stepper drive assembly
6 whereby the tire carcass mounting assembly 7 is
urged to move transversely relative to the tire
spin a~is. The magnitude of the relative motion
between tire spin and tire traverse is defined by the
ratio calculated by micro-computer 1. The tire
profile undergoes variations in geometry according to
the prescribed program whereby, the micro-computer 1
changes the ratlo be~ween tire spin and transverse
motions. This is accomplished by micro-computer 1
counting electrical pulses received from the digital
encoder 3 and compares this count to pre-programmed
value~. Upon matching the pre-programmed value of
counted digitsl encoder 3 pulses, the next programmed
ratio ls introduced into micro-co~puter 1. At this
time the relative motion between the tire rotation
and tire traverse is altered in accordance with the
newly introduced ratio.
For each tire tread profile se~ment the micro-
computer 1 using a pro~rammed ratio value, converts
pulses received from digital encoder 3 into electrical
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signals which are transmitted to the stepper motor
drive assembly 6. Duri~g this time, the micro-
computer 1 controls the transverse position relat~ve
to the circumferential position of tire carcass 4.
This relationship is maintained thr~ughout the entire
tire tread profile application operation, even though
the tire circumferential spin rate may be undergoing
velocity changes. This position ri~lationship ix
solely based upon tire carcass displacement as
represented by discrete electrical pulsas trans-
mitted by digital encoder 3. The relative mo~ion
between tire spin and ~raverse are not dep2nd~nt
upon tire velocity or time. In this manner, a
significantly more accurate and repeatable tire -
tread profile build-up may be effected, since with
the present invention it becomes possible to
directly control the tread profile build-up through
the ratio of tire spin and traverse displacements.
It will ~e understood that the speciic embodi-
ments of the invention described herein are given by
way of illustration only and that various departures
may be made therefrom, all within ~he scope of the
in~ention. The specific relationships of ribb~n
wrap to speed of application are cited merely to il-
lustrate the efficiency of the apparatus and method
and the results to be expected from the use thereof
in practice.
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