Note: Descriptions are shown in the official language in which they were submitted.
CA 02387259 2002-06-21
FASTENER DRIVING TOOL FOR TRIM APPLICATIONS
This application is a division of Canadian Patent File No. 2,267,397 filed
March
30, 1999.
BACKGROUND OF THE INVENTION
S The present invention relates generally to improvements in fastener driving
tools
and specifically to improvements relating to the useability and functionality
of such tools for
installation of trim and other decorative and finishing applications utilizing
small fasteners and
small workpieces, which will be collectively referred to herein as "trim
applications" . The tool
of the invention includes a number of improved features especially suitable to
provide enhanced
operation and user comfort when using the tool in trim applications, while
also improving ease
of tool assembly. Preferably, the tool is a combustion powered tool, but
aspects of the present
invention are similarly applicable to other tools, such as pneumatically
powered and power
actuated tools.
Portable combustion powered tools for use in driving fasteners into workpieces
are described in commonly assigned patents to Nikolich, U.S. Patent Re. No.
32,452 and U.S.
Patent Nos. 4,552,162; 4,483,473; 4,483,474; 4,403,722 and 5,263,439, which
may be
referred to for further details. Similar combustion powered nail and staple
driving tools are
available commercially from ITW-Paslode under the IMPULSE brand.
1
CA 02387259 2002-06-21
Such tools incorporate a generally gun-shaped tool housing enclosing a small
internal combustion engine. The engine is powered by a canister of pressurized
fuel gas, also
called a fuel cell. A battery-powered electronic power distribution unit
produces the spark
for ignition, and a fan located in the combustion chamber provides for both an
efficient
S combustion within the chamber, and facilitates scavenging, including the
exhaust of
combustion by-products. The engine includes a recipi~cating piston having an
elongate,
rigid driver blade disposed within a piston chamber of a cylinder body.
The wall of a combustion chamber is axially reciprocable about a valve sleeve
and, through a linkage, moves to close the combustion chamber when a workpiece
contact
element at the end of a nosepiece connected to the linkage is pressed against
a workpiece.
This pressing action also triggers a fuel metering valve to introduce a
specified volume of
fuel gas into the closed combustion chamber from the fuel cell. The metering
valve may take
the form of a solenoid valve, which is powered by the battery, or may be a
purely mechanical
valve.
Upon the pulling of a trigger, which causes the ignition of a charge of gas
iri
the combustion chamber of the engine, the piston and driver blade are shot
downward to
impact a positioned fastener and 'drive it into the workpiece. As the piston
is driven
downward, a displacement volume enclosed in the piston chamber below the
piston is forced
to exit through one or more exit ports provided at a lower end of the
cylinder. After impact,
the piston then returns to its original, or "ready" position through
differential gas pressures
2
CA 02387259 2002-06-21
within the cylinder. Fasteners are fed into the nosepiece from a supply
assembly, such as a
magazine, where they are held in a properly positioned orientation for
receiving the impact
of the driver blade. Power of the tools dif~rs according to the length of the
piston stroke,
volume of the combustion chamber, fuel dosage and similar factors.
The combustion powered tools have been successfully applied to large
workpieces requiring large fasteners, for. framing, roofing and other h::wy
duty applications.
Smaller workpiece and smaller fastener trim applications demand a different
set of
operational characteristics than the heavy-duty, "rough-in", and other similar
applications.
One operational characteristic required in trim applications is the ability to
predictably control fastener driving depth. For the sake of appearance, some
trim
applications require fasteners to be countersunk below the surface of the
workpiece, others
require the fasteners to be sunk flush with the surface of the workpiece, and
some may
require the fastener to stand off above the surface of the workpiece. Depth
adjustment has
been achieved in pneumatically powered and combustion powered tools through a
tool
controlling mechanism, referred to as a drive probe, that is movable in
relation to the
nosepiece of the tool. Its range of movement defines a range for fastener
depth-of drive.
Exemplary depth adjustment tool-controlling mechanisms are disclosed in
Volkmann U.S.
Patent No. 3,519,186, Canlas, Jr., U.S. Patent No. 4,767,043, Mukoyama U.S.
Patent No.
5,219,110, and Johnson, Jr., U.S. Patent No. 5,385,286.
3
CA 02387259 2002-06-21
Another depth-of drive adjustment having a spool on a thread for adjusting
depth is disclosed in commonly assigned U.S. Patent 5,685,473. The spool has
ribs that
engage a spool restraining element when the tool controlling mechanism is
pressed inwardly
toward the tool body. This prevents spool movement when the tool is enabled
for firing. In
these prior depth adjustment mechanisms, the operator typically obtains a
desired depth
through trial and error. If depth is altered for some reason, it may take
additional trial and
error to return to a previously used depth. This experimentation to obtain a
desired depth
slows operation of the tool, and may result in workpiece damage in trim
applications which
require a precisely controlled depth.
Another difficulty in trim applications relates to the small fasteners used.
Typically, these fasteners are fed into the nosepiece by a magazine which is
angularly
mounted below the handle used by an operator to grip and trigger the gun. They
are advanced
by a spring loaded fastener pusher, generally similar in operation to those
found in staplers.
It is preferable to prevent firing when a certain number of fasteners are
remaining, or when
1 S the fasteners are exhausted, but the resulting movements created in the
magazine by trim
sized fasteners provide very little mechanical feedback due to their small
size. For example,
typical finishing brads loaded into a magazine move in increments of about
0.060" (l.Smm).
As a result, a lockout bar moving with the brads is unable to block the larger
diameter drive
probe and related linkage, used to enable firing, upon the movement induced
after the driving
of a small diameter brad.
4
CA 02387259 2002-06-21
The fasteners used in trim applications may also be difficult to manipulate
and
load due to their small size. Rear loading, top loading, and side loading
arrangements are
known in the art. The side and top loading arrangements are more mechanically
complex
since the direction in which the fasteners are loaded into the magazine is not
in the same
direction into the nosepiece that the fasteners travel during operation. The
known rear
loading arrangement is more easily implemented, but is more difficult to use
because no
portion of the gun provides a guiding surface for a user to align a fastener,
or the beginning
of a group of fasteners, with the opening for placing fasteners into the
magazine.
User ergonomics and tool balance also play a more pronounced role in trim
applications. Manipulation of the tool to fasten horizontally disposed trim
pieces and trim
pieces in awkward positions results in user fatigue, which is amplified by a
tool which is not
balanced around the user grip area. Typical combustion tools have the handle
disposed away
from the axis of the driver blade to accommodate the fuel cell held in the
housing at a point
adjacent to the termination of the handle at the housing. This results in a
natural tendency
of the tool to lean away from the user when gripped at the handle since most
of the tool's
weight is centered near the axis of the driver blade. Recoil is also
pronounced since the
distance between the handle and the driver acts as a moment arm. A user must
oppose these
forces when using the tool, resulting in fatigue.
User comfort is also affected by tool weight and stability. Typically, the
fastener driving tools are held together by numerous screws and rivets at
various points
5
CA 02387259 2002-06-21
around tool's periphery. This increases weight and decreases rigidity. Since
the magazine
and tool housing are separate pieces, the separate fastening also can lead to
alignment
problems in delivering fasteners into the nosepiece. These operational
problems are separate
from additional assembly problems related to the same typical tool features,
which make
assembly more difficult and expensive.
Trim applications also require more exacting positioning during firing.
Typical
tools obscure an operator's sight line since the body of the tool interferes
with the view to
a portion of the workpiece proximate to the point at which the fastener will
be driven into the
workpiece.
Tools having self contained power sources generally must also be portable, and
cost is an important concern. To keep cost and weight down, many portable
tools lack an
on/off switch. To prevent unintentional operation of the tool, some operators
disengage the
battery held in the handle or some other portion of the tool. In the
combustion tools, the
battery is necessary to produce the spark and fan movement necessary to tool
operation. If
the operator is moving, for instance by climbing a ladder or scaffold, the
loosely held
disconnected battery (or batteries) may fall out. This is an inconvenience to
the operator, a
cause of damage to the battery, and a potential hazard to the operator and
anyone below the
operator.
6
CA 02387259 2002-06-21
Accordingly, the present invention disclosed seeks to provide an improved
fastener driving tool useful for driving of fasteners in trim applications and
which addresses
drawbacks in conventional fastener driving tools.
Further still the present invention seeks to provide an improved fastener
driving
tool for trim applications which has a magazine which is shaped to act as a
connection member
at the bottom of the tool to hold separate portions of the tool housing
together. Related aspects
of the invention include the provision of a magazine which extends into the
nosepiece, a
magazine having ribs for accepting pieces of the housing and a magazine having
a closed
bottom to prevent exposure of the fasteners.
Yet further the present invention seeks to provide an improved fastener
driving
tool for trim applications having a rear loading magazine under the tool's
handle, the tool
having a loading shelf defined by an extended portion of one of the tool
housing pieces so that
the shelf aids in fastener loading.
Moreover the present invention seeks to provide an improved fastener driving
tool for trim applications which includes an elongated joining element for
holding the separate
housing pieces together along the front of the tool, the joining element
including a sight
permitting an operator to position the tool over a workpiece.
Still further the present invention seeks to provide an improved fastener
driving tool
for trim applications which has a battery holder including a locked standby
position, permitting
the battery to be moved into a locked position which is out of electrical
contact with tool
operational circuits. A related aspect of the invention is to provide a tool
with a battery holder
which is movable between separate locked operational and standby positions and
includes an
indicator to indicate to an operator the position of the battery holder.
SUMMARY OF THE INVENTION
7
CA 02387259 2002-06-21
More particularly the present invention to which this divisional application
is
directed provides a powered tool for driving a driver blade along an axis in
response to power
from a power delivery source so as to impact a fastener and drive the fastener
into a
workpiece, comprising a housing having a main chamber enclosing the power
delivery source
and comprising at least two separate housing sections, a nosepiece associated
with the housing
so as to accept a fastener and axially guide the driver blade toward impact
with the fastener,
a handle and a trigger permitting an operator to actuate the power delivery
source.
In one aspect, there is a fastener supply assembly comprising a magazine for
holding a multiplicity of fasteners, wherein the magazine is interposed
between the at least two
housing sections and comprises rib members disposed on opposite sides of the
magazine for
engaging portions of the at least two housing sections so as to hold the at
least two housing
sections together.
In another aspect there is provided a fastener supply assembly associated with
the housing for supplying fasteners into the nosepiece and an elongated
joining element separate
1 S from the at least two separate housing sections and engageable with each
one of the at least two
separate housing sections for holding the at least two separate housing
sections together.
Still further in another aspect there is a fastener magazine accommodated
within
the housing below the handle, the magazine terminating in an opening for
accepting fasteners
near an end of the handle. A first one of the at least two separate housing
sections is larger
than a second one of the at least two separate housing sections such that the
first one of the at
least two separate housing sections comprises an extended portion which
extends beyond the
second one of the at least two separate housing sections so as to define a
shelf member which
projects externally outwardly from the tool housing for assisting the loading
of fasteners into
the opening of the magazine.
Further still, another aspect provides the powered tool with a fastener
magazine
operatively associated with the housing for accepting fasteners to be loaded
into the fastener
8
CA 02387259 2002-06-21
magazine and a fastener follower movable within the fastener magazine between
a
rearwardmost position at which the fastener follower engages a plurality of
fasteners disposed
within the fastener magazine so as to bias the plurality of fasteners toward
the driver blade and
a forwardmost position at which the fastener follower is disposed after a
predetermined number
of the fasteners disposed within the fastener magazine have been depleted
whereupon the tool
is no longer able to be fired. A first section of the tool is operatively
associated with the
fastener magazine and extends rearwardly beyond the rearwardmost position of
the movable
fastener follower and a second section of the tool is operatively associated
with the fastener
magazine and extends rearwardly beyond the rearwardmost position of the
movable fastener
follower. The first and second sections of the tool together define an opening
within the
magazine through which fasteners can be loaded into the fastener magazine and
the first section
of the tool is longer than the second section of the tool such that the first
section of the tool
comprises an extended portion which extends beyond the second section of the
tool so as to
define a shelf member which is externally accessible for assisting the loading
of fasteners into
the opening of the magazine.
Moreover the power tool, in a still further aspect, has a fastener supply
assembly
associated with the housing for supplying fasteners into the nosepiece with an
elongated hollow
portion provided within the housing and having a longitudinal extent. Power
contacts for the
tool are disposed within the elongated hollow portion of the housing and a
battery holder,
housing an electrical power supply battery is movably disposed, in a
substantially longitudinal
manner within the elongated hollow portion of the housing, between a first
locked operational
position at which battery contacts are electrically connected to the power
contacts of the tool
so as to supply electrical power to the tool and a second locked standby
position at which the
battery contacts are electrically disconnected from the power contacts of the
tool so as to
operatively disable the tool while the battery holder and the battery, are
lockingly retained
within the hollow portion of the housing of the tool.
9
CA 02387259 2002-06-21
The preferred tool also includes a modified trigger and handle assembly. The
handle and trigger are moved inward toward the driver axis as compared to a
conventional
tool. This improves tool balance and user comfort.
In the preferred embodiment, the fastener magazine provides a unitary path for
fasteners into the nosepiece, and serves to hold together separate portions of
the housing for
the tool. The magazine includes ribs for accepting the separate halves of the
housing, which
lock into the ribs to bind the housing portions together. The magazine
preferably includes
a closed aluminum bottom to keep the fastener tips from being exposed. An
elongated
joining element serves to similarly act as an assembly point along the front
of the tool. The
element includes a rib which acts as a sight for the operator to properly
position the tool over
a workpiece. Alternatively, a rifle type sighting aid may be used in place of
the rib.
Separately and combined, the magazine and joining simplify assembly and
improve tool
rigidity and component alignment.
Preferably, one of the housing portions extends more than the other at a rear
portion where the magazine terminates with an opening into which fasteners may
be loaded.
This extended portion provides a fastener loading shelf. The shelf acts as a
guide to assist
an operator in the loading of fasteners into the magazine opening.
An additional advantage of the preferred tool is the battery holder, which
includes separate locked standby and operational positions. An operator may
move the
battery into the locked standby position to remove the battery (or batteries)
from electrical
CA 02387259 2002-06-21
contact with the electrical circuits of the tool. The battery holder may
include an "off ' or
similar indication for when the battery holder is placed in the standby
position, or an "on"
or similar indication when the battery holder is in the operational position.
When placed in
the standby position, the battery is still held securely in the tool so that
the tool may be easily
transported.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features, objects and advantages of the invention will be apparent by
reference to the detailed description and the drawings, of which:
FIG. 1 is a partially cut away side view of the preferred fastener driving
tool;
FIG. 2 is an opposite side view of the fastener driving tool of FIG. 1;
FIG. 3 is a partial cross section of an incremental drive depth controller of
the
preferred fastener driving tool;
FIG. 4 is a section taken at line 4-4 in FIG. 3;
FIG. 5 is a partially cut away side view of a portion of the preferred tool
1 S including a distance amplifying lockout;
FIG. 6 is a partially cut away alternate view of the portion of the preferred
tool
including the distance amplifying lockout;
FIG.7 is a perspective relational view of the preferred tool, a preferred
fastener
magazine and a preferred fastener follower;
11
CA 02387259 2002-06-21
FIG. 8 shows a portion of the preferred tool and magazine in an uncompleted
assembly state;
FIG. 9a shows the portion of the preferred tool in FIG. 8 in a completed
assembly state;
FIG. 9b illustrates a completed front assembly of the preferred tool of FIG.
8;
FIG. 9c is a top viez-~ of a joining element from FIG. 9b;
FIG. 10 is a perspective partially exploded view illustrating the preferred
tool
and its battery holder;
FIG. 1 I is a partial side view of the battery holder mounted in the preferred
tool
in a locked standby state;
FIG. 12 is a section taken along line 12-12 in FIG. 11 w i t h Fi G . 1 ?. A
an enlarged portion of FIG. l2: and
FIG. 13 is a perspective view of a portion of the preferred tool showing its
fastener loading shelf.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
1 S Broadly stated, the present invention concerns an improved fastener
driving
tool that is especially suited for installation of trim, and other decorative
and finishing
applications utilizing small fasteners and small workpieces, which will be
collectively
referred to herein as "trim applications". The tool of the invention is
maneuverable and
12
CA 02387259 2002-06-21
comfortable, it provides repeatable depth control, and includes a number of
features which
render use and assembly more efficient and reliable.
Referring now to FIGs. 1 and 2, the preferred embodiment of a compact
fastener driving tool for trim applications is generally designated 10. A
housing I2 of the
S tool 10 encloses a self contained internal power source 16 within a housing
main chamber
17. As in conventional combustion tools, use power source 16 includes a
combustion
chamber that communicates with a cylinder. A piston within the cylinder is
connected to the
upper end of a driver blade 18. Through depression of a trigger 20, an
operator induces
combustion of a measured amount of propellant within the combustion chamber,
causing the
driver blade 18 to be forcefully driven downward into a nosepiece 22. The
nosepiece guides
the driver blade 18 to strike a fastener that had been delivered into the
nosepiece via a
fastener magazine 24. Thus, general operation is like that of conventional
combustion
fastener driving tools. From the following description of novel features of
the preferred tool
10, artisans will also appreciate that many of the features of the present
invention can be
advantageously applied to fastener driving tools having alternate power
sources, such as
pneumatic and powder actuated tools.
An important feature of the preferred tool I O is its ability to provide
discrete
and repeatable depth control adjustment. Referring now to FIGS. 1, 3 and 4, an
incremental
controller for providing a discrete number of repeatable fastener driving
depth settings is
generally designated 26. The incremental controller 26 cooperates with a
fastener drive
13
CA 02387259 2002-06-21
probe 28, and permits a user to adjust the relative relationship between the
drive probe 28
and the nosepiece 22 over a limited range. The limited range is defined by
threads 30
disposed at an upper end of the drive probe 28. An operator rotates a knob 32
to move the
drive probe 28 inwardly and outwardly. The range of movement is divided into a
discrete
number of selectable positions by an incrementer 34.
The incrementer 34 preferably comprises a detent 36, for example a ball
bearing, that cooperates with a nonrotating polygonal surface 38. The
polygonal surface
shown in FIGs. 3 and 4 is octagonal, having the effect of dividing each full
rotation of the
knob 32 into eight discrete and repeatable settings. The detent 36 is
preferably spring loaded
via a spring clip 40 held on by a sleeve 42 to frictionally engage the
polygonal surface 38.
An operator feels and may hear "clicks" indicating distinct positions as the
knob 32 is
rotated. Numbers or other indicia may be used in conjunction with the knob 32
and/or the
lower end of the probe 28 to assist in selection of repeatable discrete
positions. In a preferred
embodiment, "flush" and "deep" are on a portion of the housing near the knob
32. In
addition, the drive probe 28 preferably includes a notch which aligns with a
lower portion
of the nosepiece 22 when the drive probe is set to a flush drive depth. The
polygonal surface
38 may be formed as an integral part of a linkage member 44 used to link the
drive probe 28
eventually to a combustion chamber 200 which seals with the cylinder head (not
shown) of
the power source 16. Alternatively, the polygonal surface 38 may be formed
from a bent
wire or member wrapped around a portion of the linkage member 44.
14
CA 02387259 2002-06-21
Another important feature of the invention concerns the preferred tool's
ability
to disable firing in response to the discharge of a single small fastener,
such as those typically
used in trim applications. As seen in FIG. 2, a fastener follower 46 rides in
a portion of the
magazine 24 and moves an equal amount to the diameter of a fastener after a
fastener has
been driven by the driver blade 18. For example, typical finishing brads
loaded into a
magazine move in increments of about 0.060" (l.Smm). This p~wides insufficient
movement to block movement of components that enable firing of the tool.
Specifically, the
drive probe 28 typically has a diameter of about .156".
In the tool 10, the primary components which enable combustion include the
drive probe 28, linkage 44, combustion chamber 200, valve sleeve 45, and a
cylinder head
which is not shown (see FIG. 1). A spring 48 biases the linkage 44, and
accordingly the
probe 28, downward. In this state, the tool 10 is disabled from firing because
the combustion
chamber is not sealed at the top with the mating unshown cylinder head. Firing
is enabled
when an operator presses the drive probe 28 against a workpiece. This action
overcomes the
spring force, causes the combusiton chamber 200 to move upward about the valve
sleeve 45
and seal the combustion chamber by mating with the cylinder head, and also
induces a
measured amount of propellant to be released into the combustion chamber from
a fuel
canister S0. As is known in the art, other actions may be initiated by the
pressing of the
drive probe, such as actuation of a fan to help combustion and loading of a
fastener into the
nosepiece 22 from the magazine 24.
CA 02387259 2002-06-21
Referring now to FIGs. 5 - 7, shown is a distance amplifying lockout 52 that
amplifies the movement of the fastener follower 46 after a rod 54 contacts its
contact point
56, which is located between its pivot mounting 58 and its engagement end 60.
The rod 54
is preferably flexible to aid in assembly when housing halves 12a and 12b are
brought
together (see FIG. 8). The rod 54 must be flexible enough to bend over the
distance
amplifying lockout. It will either bend into place at the contact point when
the i:~using
halves are brought together or after the fastener follower 46 is pulled back
for the first time.
The contact point 56 is located near the axis of rotation defined by the pivot
mounting 58 so
that further movement of the rod 54 after contacting the point 56 produces an
amplified
movement of the engagement end 60. In the illustrated embodiment, a .060"
movement at
the contact point 56 created by the discharge of a single trim fastener is
translated into a
.200" movement of the engagement end 60. The pushing of the rod 54 at the
contact point
56 overcomes a light spring force supplied by a light spring 62 to move the
engagement end
60 into a position which will block a terminal end 64 of the probe 28 from
moving upward.
As is best seen in FIG. 5, the engagement end 60 is preferably shaped to
accommodate the
terminal end 64 of the probe, and an opposite surface 66 mates with a solid
(preferably steel)
portion 68 of the tool 10. The opposite surface 66 jams solidly against the
solid portion 68,
while the curve in the engagement end 60 draws the lockout 52 inward after it
engages the
terminal end 64, thereby ensuring engagement of the full diameter of the probe
28. This
reinforced position with the engagement end 60 in an axis of movement of the
terminal end
16
CA 02387259 2002-06-21
64 of the probe 28 will oppose significant forces applied by an operator
trying to actuate the
tool 10, and provide a clear indication that the magazine 24 is low or has
been emptied of
fasteners. As will be appreciated by artisans, it is a matter of design choice
to determine the
number of fasteners remaining when the lockout 52 is actuated. Such
adjustments may be
accomplished, for example, by altering the length of the rod 54.
It has been mentioned that the rod 54 must be resilient enough to bend out of
the way of lockout 52 when halves of the housing are rotated together. Other
factors are also
important with respect to the magazine 24, follower 46 and lockout 52. First,
the follower
46 should contact a portion of the housing before the lockout 52 is pushed to
a breaking
point. This protective position is illustrated in FIGs. 2 and 5. This protects
the lockout 52
from accidental breakage when an operator accidentally allows the follower 46
to slam back
toward the lockout 52. Second, at the point of disabling, the follower 46
should keep light
pressure on remaining fasteners. Thus, the housing 12 should not be contacted
by the
follower 46 at that point, which is when 10 fasteners remain in a preferred
embodiment. In
other words, after the 1 lth remaining fastener, for example, is shot, the rod
54 activates the
lockout 52 while keeping pressure on the 10th brad to keep the remaining brads
in position.
Once operation is prevented, an operator may pull back the fastener follower
46 to move it back along the magazine 24 so that more fasteners may be loaded
into the
magazine 24. It is a bypass type follower, so a bar 70 and associated spring
71 pivotally
control a fastener engager 72 so it will travel over fasteners in the magazine
24 on the way
17
CA 02387259 2002-06-21
back, or travel over fasteners on the way forward when an operator presses the
bar 70. When
bar 70 is released and the follower 46 is behind a group of fasteners, the
engager 72 will
engage the rearmost fastener upon meeting it. A constant force negator spring
(not shown)
is rolled into a molded pocket within the housing 12, and exerts force to pull
the fastener
follower 46 toward the nosepiece 22 and engage the engager 72 with the
rearmost fastener
within the magazine 24. After lockout, the operator overcomes this force to
pull the fastener
follower 46 back, and the distance amplifying lockout 52 is moved to a resting
position
through force supplied by the light spring 62. The resting position is def ned
by a stop end
74 of the lockout 52, which abuts a solid portion 76 of the tool 10.
The preferred tool 10 also provides balance and maneuverability, which reduce
user fatigue and permit precision handling of the tool. Referring primarily to
FIG. 1, with
further views included in FIGs. 2 and 7, the trigger 20 of the present tool is
proximate to the
axis defined by the driver blade 18. Proximate, as used herein, means that the
trigger is very
near the cavity of the housing that includes the power source 16. This is
accomplished
through a unique handle, grip, and fuel canister arrangement 78.
The housing I2 includes a curvature 80 that permits a handle 82 to extend up
to the portion of the housing which accommodates the power source 16. The
curvature also
provides a comfortable and stable gripping location. Overall, the handle 82 is
shaped to
accommodate the shape of an operator's hand, as best seen in FIG. 7. Unlike
conventional
18
CA 02387259 2002-06-21
combustion tools, the handle 82 partially wraps around, and the trigger 20 is
completely
under, the fuel canister 50.
A significant result of the assembly 78 is that the trigger 20 may be disposed
near the tool's center of gravity. This trigger and handle position, within an
imaginary
S extension of the fuel canister S0, provides enhanced operation since the
user will not have
to oppose the tendency of the tool to tip, as in tools which must be gripped
at other locations.
Compared to such other locations, the trigger and handle position of the
present tool 10 also
reduces recoil felt by an operator during operafiion since the moment imparted
to an
operator's wrist is reduced by virtue of the shorter moment arm created by the
novel trigger
position. In previous combustion tools, the handle and grip ended at a
position adjacent to
the fuel canister or its imaginary extension, causing a larger moment to be
imparted to an
operator's wrist. Further comfort may be provided by an elastomeric portion 83
formed at
the top of the handle 82. This portion 83 will reduce shock imparted to an
operator's hand
during tool operation. The trigger 20 preferably includes a similar
elastomeric portion.
These combine to reduce the shock to an operator's hand during operation.
Fastener delivery of the present tool 10 is rendered more reliable by the
magazine structure depicted in FIG. 7, and by the associated manner of
assembly depicted
in FIGs. 8 and 9. The magazine 24 serves as a primary assembly member for two
halves I2a
and 12b of the housing 12, and extends into the nosepiece 22 in a completed
assembly state.
This serves to unify alignment of the fastener delivery path, defined by a
fastener channel 84,
19
CA 02387259 2002-06-21
since a fastener 86 is ejected directly from the magazine 24 to a point in the
nosepiece 22 that
is within the driving axis defined by the driver blade 18.
The magazine 24 includes opposite ribs 88a and 88b which accept and lock
corresponding tooth portions 90a and 90b of the housing halves I 2a and 12b.
The bottom 91
of the magazine 24 is rounded and closes the fastener channel 84 to prevent
the sharp ends
of fasteners from being exposed outside the tool 10.
A separate elongated joining element 92 includes locking channels 93 (FIGs.
9b & 9c) similar to those on the magazine, and serves to lock corresponding
portions of the
housing halves 12a and 12b along the front of the tool 10. The joining element
92 includes
an alignment sight 94. The alignment sight 94 is generally parallel to the
driver blade,
angling with the housing 12 somewhat inward toward the nosepiece 22, and
provides an aid
to an operator attempting to align the tool 10 with precision over a
workpiece. As illustrated
in FIGS. 9b and 9c, the sight 94 comprises a rib formed on the length of
joining element 92.
After the halves 12a and I2b are brought together and locked by the magazine
24, the joining
element 92 is slid down to lock the halves 12a and 12b at the front of the
tool 10. Best seen
in the top view of FIG. 9c, the locking channels 93 hold the two halves
together along the
front of the tool 10. The sighting might also include a rifle tab 94a and
alignment aid 94b
instead of the rib (as shown in FIGs. 1 and 2). In such case the tab 94a is
preferably formed
on the housing 12 and the aid 94b at a lower portion of the joining element 92
(see FIGs. 1
and 2).
CA 02387259 2002-06-21
Assembly is completed by a number of recessed screws 96 in the handle area
(see FIG. 1), and a bolted-on cap 98. Bolt holes 99 (FIG. 9b) hold the bolts.
Any similar
fastening element may replace the screws, including but not limited to bolts
or direct snap
together members. The cap includes air openings, and a screen and grill are
preferably used
to filter and protect the openings. Such a grill may snap onto the cap 98 and
lock an
intervening screen into place. The screen may include a gasket around its
circumference.
This arrangement facilitates occasional replacement of the screen. The cap 98,
joining
element 92, and magazine 24 provide rigidity and alignment not accomplished by
mere point
fastening arrangements, while also reducing part count and simplifying
assembly. These
assembly members are preferably formed of hard plastic to reduce tool weight.
Part count is also reduced by the absence of an electrical on/off switch. This
is common to many low cost tools that rely on batteries for some form of
electric power.
However, the present tool 10 includes a unique battery holder 100 (see FIGS. 1
and 10-12)
having separate locked operational and standby positions, permitting an
operator to
effectively turn the tool off by disconnecting the battery supply, while
simultaneously
locking the battery holder 100 in place to avoid having it fall out.
As seen in FIG. I0, the battery holder 100 may be removed from a hollow
portion 102 of the handle 82. As in typical tools including battery holders,
the battery holder
includes contacts to contact electrical elements in the tool, so that
necessary power can be
delivered to tool circuitry. However, the battery holder 100 and hollow
portion 102 also
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CA 02387259 2002-06-21
provided a locked non-operational position, shown in FIGS. 11 and 12, where
such electrical
contact is nc~t made to thereby electrically disable the tool 10.
Specifically, separate holes 104a and 104b, which also might be mere
depressions, are provided for accommodating a biased tooth 106 of the battery
holder 100.
The tooth 106 preferably includes a sloped leading edge 108 to facilitate
sliding of the holder
100 into the hollow portion 102, which includes a corresponding slope 110.
Once the tooth
106 reaches the first depression 104a it pops into the depression and locks
the holder into the
nonoperational position shown in FIG. 12. In that position battery holder
contacts 112 are
separated from tool contacts 114 so that the batteries I I6 cannot supply
electricity through
contacts 112 and 114 to tool power circuits that are electrically connected to
contacts 114.
In this position, the tool 10 can be placed in any orientation without wonry
that the battery
holder 110 will fall out. Accordingly, inconvenience and potential injury are
avoided while
a switchless manner of electrically disabling the tool is provided.
An indication 118, such as "off', may also be provided to indicate the tool's
state of readiness. In FIG. 1 I, the indication simply takes the form of
lettering on the surface
of the battery holder 100. The "off' lettering becomes aligned with the hole
104b when the
tooth is in the hole I04a. Alternatively or additionally, a LED indicator Ll8a
(see FIG. I)
might be used to indicate tool readiness when the holder is in a separate
locked operational
position.
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CA 02387259 2002-06-21
An operator moves the battery holder into the separate locked operational
position by depressing a tab 120 to overcome the upward bias of the tooth 106.
Once the
tooth is released from the hole 104a, the battery holder 110 may then be slid
forward until
the contacts 112 contact the contacts 114 and the tooth 106 clicks into the
hole 104b. An
indication, such as "on", may also be provided in this locked operational
position, through
hole 104a, or through We LED 118a, or through other suitable means.
The small sized trim fasteners for use with the preferred tool may be
difficult
to toad into the magazine 24, even when they are bundled together in groups of
multiple
fasteners in a fashion similar to groups of staples. The preferred tool 10
renders loading
easier through provision of a shelf 122. The shelf 122 is preferably formed as
an extension
of one of the housing halves 12a or 12b and preferably includes an angled
portion 123. As
seen from FIG. 13, the shelf 122 and angled portion (also shown in FIG. 9b)
will serve as a
guide to guide fasteners into a fastener opening 124 that leads to the
fastener channel 84 of
the magazine 24.
As described above with reference to the drawings, features of the present
invention provide for an improved fastener driving tool for trim applications.
While the
preferred embodiment is a combustion tool, artisans will appreciate that
features of the
present invention might also be individually or severally applied to other
tools, such as
battery powered electric tools, pneumatic tools, and powder actuated tools.
Thus, while a
particular embodiment of the invention has been shown and described, it will
be appreciated
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CA 02387259 2002-06-21
by those skilled in the art that changes and modifications may be made thereto
without
departing from the invention in its broader aspects and as set forth in the
following claims.
24
