Note: Descriptions are shown in the official language in which they were submitted.
CA 02441171 2007-07-20
CARTRIDGE STRIP ADVANCING MECHANISM
FOR FASTENER DRIVING TOOL
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention is directed to powder actuated tools, and more
particularly to a
powder actuated fastener driving tool having automatic powder cartridge strip
indexing.
2. Description of the Related Art
[0003] Powder actuated fastener setting tools are known generally. U.S. Patent
No. 5,429,291
entitled "Conipression Actuated Tool For Driving Fasteners" assigned commonly
with the present
application, for example, discloses a powder driven tool including a manually
operated spring
biased indexing lever pivotally mounted thereon for advancing a magazine strip
retaining a
plurality of powder cartridges therein through a magazine channel of the tool.
[0004] For many powder actuated tools it is desirable to have a mechanism that
indexes a strip
of explosive powder cartridges after the tool has been fired so that a fresh
cartridge is ready for
firing without the operator having to do anything. An example of an indexing
mechanism is
disclosed in the commonly assigned U.S. Patent No. 6,547,123 issued April 15,
2003 entitled
"Powder Driven Fastener Setting Tool," the disclosure of which may be referred
to for further
details. The above referenced patent teaches the use of a reciprocating sleeve
which drives an
indexing lever to index a strip of cartridges along a magazine channel. The
sleeve reciprocates
during firing of the tool, and is returned when an operator pushes the sleeve
into its original
position.
1
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
[0005[ In some applications it may be desirable to make the indexing of the
cartridge
strip automatic, so that the operator does not have to perform the added step
of pushing
the reciprocating sleeve back into its original, pre-firing position. However,
the indexing
of the cartridge strip still must be driven by the motion of some part of the
fastener
driving tool. One possible part to use to drive the indexing of the cartridge
strip is to use
the motion of a trigger, wherein the trigger also actuates a fning mechanism
of the tool.
U.S. Patent 6,272,782 to Dittrich et aI. discloses a cartridge advancing
mechanism linked
to the trigger using connected pivoting levers.
[00061 A problem that has occurred with tools using pivoting levers has been
"dead
stop" of the trigger. When the trigger and advancing mechanism are directly
linked, such
as with connected pivoting levers, the trigger can come to a hard, or dead,
stop when the
advancing mechanism comes to a stop as it engages with the cartridge strip.
Dead
stopping can become uncomfortable for an operator due to repetitive use of the
tool.
100071 Another problem that has been common with advancing mechanism for
explosive powder actuated tools is complexity requiring a large number of
interconnected
parts and moving parts to ensure operation of the advancing mechanism.
1000$1 What is needed is a fastener driving tool which uses the motion of the
trigger
to drive an automatic indexing of a strip of explosive cartridges, while
requiring fewer
parks and overcoming the dead stop phenonienon of the prior art.
BRIEF SUMMARY OF TI:iE INVENTION
[00091 In accordance with the present invention, a powder driven fastening
tool is
provided with a novel and inventive cartridge strip advancing mechanism. The
fastening
tool comprises a magazine channel for feeding a strip of cartridges to a
firing mechanism,
a trigger for actuating the firing mechanism, the trigger being movable
between a first
position and a second position, an advancing lever pivotal.ly coupled to the
tool, the
advancing lever having a strip engagement portion extending into the magazine
channel
for indexing the strip, an advance link cammingly engaged with the advancing
lever and
operationally associated with the trigger, the magazine engagement portion
being in a
first position in the magazine channel when the trigger is in the first
position, and the
magazine strip engagement portion being in a second position in the magazine
channel
when the trigger is in the second position.
2
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
[00101 These and other objects, features and advantages are evident from the
following description of an embodiment of the present invention, with
reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a partial sectional view of an exemplary powder actuated tool in a
first
configuration.
FIG. 2 is a partial sectional view of the exemplary powder actuated tool in a
second configuration.
FIG. 3 is a top view of an exeraaplary magazine strip indexing lever.
FIG. 4 is a partial sectional view of the magazine strip indexing lever
engaged
with a magazine strip.
FIG. 5 is a perspective view of an alternative powder actuated tool.
FIG. 6 is a perspective view of a firing mechanism and a cartridge strip
advancing
mechan.ism of the powder actuated tool.
FIG. 7 is as side sectional view of the powder actnated tool.
FIG. 8 is a partial side sectional view of the castridge strip advancing
mechanism
in a first position.
FIt'a. 9 is a partial side sectional view of the cartridge strip advancing
mechanism
in a second position.
FIG. 10 is a sectional view of the cartridge strip advancing mechanism tak.en
along line 10-10 in FIG. 8, wherein the advancing mechanism is in the first
position.
FIG. I 1 is a sectional view of the cartridge strip advancing mechanism whemin
the advancing mechanism. is moving from the first position to the second
position.
FIG. 12 is a sectional view of the cartridge strip advancing mechanism taken
along line 12-12 in FIG. 9, wherein the advancing mechanism in is the second
position.
FIG. 13 is a sectional view of the cartridge strip advancing mechatusm in the
first
position, wherein the advancing mechanism has indexed a cartridge strip from
the second
position to the first position.
FIG. 14 is a perspective view of the advancing mechanism shown with a breach
block.
3
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
FIG. 15 is a perspective view of the advancing mechanism shown in an uncocked
state of the tool.
FIG. 16 is a perspective view of the advancing mechanism shown after an
advancing lever has completed its movement during ficing of the tool.
FIGS. 17A and 17B are perspective views showing an adjustable connection
between the trigger and an advance link of tlae advancing mechanism in order
to provide
fine tuni.ng,
DETAILED DESCILIPTtON OF THE INVENTION
100111 Gen.erally, a magazine strip or some other member is incrennentally
indexed
through a channel of a fastening tool by an indexing lever actuated by a lever
cam that
moves between first and second positions with some other portion of the tool.
[0012] ln the exxemplary powder driven fastener setting tool 10 of FIG. 1, a
magazine
strip 11 is fed or indexed along a magazine channel 20 disposed in a pistol-
type grip 12
of the tool. The magazine channe120 extends to and through a firing chamber
disposed
between a barrel breech end 32 and a breech block 42 of the tool.
100131j The magazine strip 11 retains a plurality of spaced apart explosive
cartridges
13 that are sequentially positioned in alignment with a cai-tridge recess in
the breech end
of the barrel, for accommodation therein during detonation, as the magazine
strip is
indexed through the magazine channel.
100141 In other embodiments, the magazine channel may be configured
differently,
and more generally it may be any passage, or channel, in the tool through
which it is
desirable to move, or index, a magazine strip or some other member.
[4015] In FIG. 1, a lever cam 50 is coupled to a compression triggering
mecharnism of
the tool 10, and more particularly to a spring biased sleeve 60 that
reciprocates between
first and second positions during operation of the tool.
100161 The firing mechasiism sleeve is aligned substantially axially with the
baxrel of
the tool and reoi.procates along its axis upon compression thereof against the
spring bias.
100171 Particularly, in FIG. 2, a spring 14 disposed between the breech block
42 and
the sleeve 60 biases the sleeve to the first position when the spring is
relatively expanded.
The sleeve is movable to the second position against the spring bias, as
illustrated in I-0IG.
4
CA 02441171 2003-09-17
"Cartridge Strip Advancing ivlechanism
For Fastener Driving Tool"
1, upon application of an axial compression force thereto as is known
generally by those
having ordinary slcill in the art.
[0018] Alternative exemplary compression triggering mechanisms in powder
driven
fastener setting tools are known generally and the operation thereof is
disclosed more
fully, for example, in the referenced U.S. Patent No. 5,429,291 entitled
"Compression
Actuated Tool For Driving Fasteners", the di.sclosure of which is incorporated
herein by
reference.
[00191 In FIGS. I and 2, the lever cam 50 extends from an integral flange 52
that is
coupled, for example by screw thread or other engagement, to the sleeve 60 and
particularly to a handle portion 62 thereof. The exem.plary handle portion 62
is assembled
with the sleeve 60 and abuts a firing pin actuating spring within the sleeve.
100201 The exemplary handle portion 62 includes an optional pole connector 64,
to
which may be coupled, for example by screw thread or other engagement, an
extension
pole.
[0021] Altern.atively, the handle portion 62 may be formed integrally with the
sleeve
60, or tlae handle portion 62 may be formed integrally with the flange 52 and
the lever
cam 50.
[0022] In other embodiments, the handle portion 62 and flange 52 may not be
required, for example in embodiments that do not include a firing pin
actuating spring.
In this embodiment, the lever cam 50 is an integral part of or is coupled
directly to the
sleeve or to some other member coupled thereto extending axially from the rear
end
.portion of the tool.
[00231 In still other alternative embodiments, the lever cam 50 may be coupled
to
some other reciprocating portion of the tool, for example to the barrel
thereof.
[0024] The tool also comprises an indexing lever 70 pivotally coupled thereto,
for
example by a pivot pin 72 or some other pivoting member or meanbers. The
indexing
lever generally comprises a magazine engagement portion and a cam f'ollower
portion
disposed on generally opposite sides of the pivot pin in the exemplary
embodiment.
100251 The cam follower portion of the indexing lever is cammingly engaged
with
the lever cam as the lever carn moves between first and second positions in
unison with
the reciprocating portion of the tool to which it is coupled, thereby pivoting
the indexing
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
lever.
100261 In FIGS. i and 2, the lever cam 50 includes a rfa.mped cam slot 56, and
the
cain follower portion of the indexing lever 70 includes a lever pin 74 that is
disposed in
and follows the ramped cam slot 56 as the lever cam 50 moves with the sleeve
between
the first and second positions. Particularly, the lever pin 74 moves between
first and
second positions along the ramped cam slot 56 as the lever cam 50 moves,
between its
first and second positions in unison with the reciprocating portion of the
tool to which it
is coupled.
[0027] Generally, the magazine engagement portion of'ttae indexing lever
extends
into the magazan.e channel where it engages and indexes the magazine strip
during
movement of the indexing lever toward the firing chamber.
[00251 FIG. 3 iIlustrates the exemplary indexing lever 70 having a known
ratcheting
magazine engagement portion with a spring biased tooth 76 for engaging the
magazine
strip. In other embodiments, however, other magazine engagement configurations
may be
employed.
[00291 The reciprocating action of the lever cam 50 pivots the indexing lever
70
back and forth to locate the magazine engagement portion thereof between first
and
second positions in the magazine channel of the tool, alternately toward and
away from
the firing chamber.
[0030] In FIG. 2, when the sleeve 60 is extended by the spring 14, the
magazine
strip engagement portion of the indexing lever is positioned toward the firing
chamber.
And in FIG. 1, when the sleeve is depressed or compressed against the bias of
the
spring 14, the magazine strip engagement portion is posit.ioried away from the
fu-ing
chamber.
[0031] FIG. 4 illustrates the magazine engagement portion of the indexing
lever and
particulariy the ratcheting tooth 76 thereof engaged with spaced apark notches
80
disposed along a side of the magazine strip 82.
[0032) The magazine strip is indexed upwardly in FIG. 4 as the indexing lever
70
moves from the position away from the firing chamber, illustrated in FIG. 1,
to the
position toward the firing chamber illustrated in FIG. 2. During this upward
motion of the
magazine engagement portion of the indexing lever, the tooth 76 thereof is
spring biased
6
CA 02441171 2007-07-20
into a notch of the magazine strip, notch 80 in FIG. 4, whereby the magazine
strip is indexed
upwardly.
[0033] As the magazine engagement portion of the indexing level moves away
from the firing
chamber, from the position illustrated in FIG. 2 to the position illustrated
in FIG. 1, the tooth
76 is withdrawn against its spring bias from the notch without moving the
magazine strip
downwardly. In FIG. 4, as the magazine engagement portion of the indexing
lever moves
downwardly, the magazine engagement portion is withdrawn from the notch 80 and
is moved to
a lower position, where it engages a lower notch 83 on the magazine strip 82.
[0034] The incremental indexing of the magazine strip thus proceeds with the
reciprocation of
the firing mechanism or other moving portion of the tool to which the indexing
lever is coupled.
[0035] In the above-mentioned embodiment, the reciprocating motion of sleeve
60 is used as the
driving motion behind the indexing of cartridge strip 82. As described above,
this embodiment
requires an operator to push sleeve 60 back into position to return indexing
lever 70 into its
original, pre-firing position shown in FIG. 1. It is preferred that tool 10 be
designed so that all
parts of tool 10 return to their pre-firing position automatically, including
indexing lever 70.
[0036] Turning to FIG. 5, an embodiment of a fastener driving tool 110
includes a spring 116
to bias a muzzle 118 into an extended pre-firing position with respect to a
housing 122 of tool
110. Tool 110 includes a back end 124 and a front end 126.
[00371 Turning to FIG. 7, a firing mechanism 130 is contained within back end
124 of housing
122 for firing explosive cartridges 113 in a firing chamber 134 to drive a
piston 136 in the
driving direction to drive fasteners 138. The front end 126 includes muzzle
118, a magazine 140
for feeding a collation strip 144 of fasteners 138 to muzzle 118, and a clutch
(not shown) for
rotating muzzle 118 and magazine 140 with respect to housing 122, allowing
magazine 140 to
be set in various orientations.
[0038] Examples of a preferred magazine and a preferred clutch are disclosed
in the commonly
assigned patent applications entitled "Magazine Assembly With Stabilizing
Members," having
Canadian Patent File No. 2,441,149 "Lock Out Mechanism For Powder Actuated
Tool,", having
Canadian Patent File No. 2,441,145 and "Magazine Clutch Assembly," having
Canadian Patent
File No. 2,440,941, all filed on September 18, 2002, the disclosure of which
may be referred
to for further details.
7
CA 02441171 2007-07-20
[0039] Continuing with FIG. 7, tool 110 includes a barrel 132 enclosed within
housing 122, and
a muzzle 118 extending axially away from housing 122. Housing 122, barrel 132
and muzzle
118 are all generally cylindrical in shape having a common central axis 146
extending throughout
the length of tool 110. Barrel 132 encloses piston 136 which drives fasteners
138 into a substrate
148, wherein piston 136 is also generally cylindrical in shape and is aligned
coaxially with barrel
132 and muzzle 118. Muzzle 118 includes a bore 152 for axially guiding a
driving 137 of piston
136 and fasteners 138 toward substrate 148.
[0040] Housing 122 includes a handle 112 laterally extending away from axis
146. Handle 112
provides a location for an operator to hold when actuating tool 110. A trigger
160 is connected
to handle 112 for actuating firing mechanism 130 and firing tool 110.
[0041] FIG. 7 shows tool 110 driving fasteners 138 generally from the right to
the left.
However, tool 110 can be operated in several different orientations, such as
to drive fasteners 138
into a vertically aligned substrate 148 so that fasteners 138 are driven
horizontally from left to
right, or tool 110 can be operated so that fasteners 138 are driven vertically
upward or downward
into substrate 148. Therefore, for the purpose of discussion, any reference to
the direction in
which a fastener 138 is driven, such as toward the left in FIG. 7, is
generally referred to as the
driving direction or leading direction and any reference to the opposite
direction, toward the right
in FIG. 7, is generally referred to as the trailing direction.
[0042] FIG. 7 also shows a cartridge strip 111 being indexed generally upward.
However, as
described above, tool 110 can be operated in several different orientations.
Therefore, the
direction in which cartridge strip 111 is indexed, such as upwardly in FIG. 7,
is generally
referred to as the indexing direction. For purposes of discussion, upwardly
and above will refer
generally to the indexing direction and downwardly and below will refer
generally to a direction
opposite the indexing direction.
[0043] Muzzle 118 is pushed against substrate 148 when tool 110 is to be used
to
8
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
drive a fastener 138 into substrate 148. Pushing against substrate 148
overcomes the
biasing force of spring 116, so that muzzle 118 is forced in the trailing
direction with
respect to housing 122 into a retracted ready-to-fire position. Muzzle 118 is
aligned
coaxially with barre1132 and is adjacent to barre1132 in the driving
direction. When
muzzle 118 is pushed in the trailing direction by substrate 148, muzzle 118
engages
barrel 132 and biases barrel in the trailing direction as well. As barre1132
is pushed in
the trailing direction, it engages a cocking rod 162, shown in FIG. 6, which
enables a
firing mechanism 130, allowing too1110 to be fired. The mechanism described
above
requires that an operator push muzzle 118 into the retracted position relative
to housing
122 before tool 110 can be fired so that tool 110 cannot be actuated unless
muzzle 118 is
pushed into the retracted position.
[00441 Trigger 160 is connected to handle 112 so that trigger 160 can. be
pulled by an
operator from a first pre-firing position, shown in FIG. 8, to a second fired
position,
shown in FIG. 9, actuating a futing mechanism 130 which fires a cartridge 113
placed
within a firing chamber 134. Trigger 160 is biased into the first, pre-
fsrirag. position by a
trigger spring 161. In one enibodiment, best seen in FIG. 15, trigger 160 is
mounted for
reciprocatory movement from a fixed trigger support 165 r.nounted to tool
housing 122
against the bias of trigger spring 161, which is interposed between trigger
160 and trigger
support 165
[00451 Turning to FIGS. 6 and 7, firing mechanism 130 includes cocking rod
162, a
firing pin 164 and a firing spring 166 to bias fnring pin 164 toward cartridge
113.
Coaking rod 162 is adjacent to barrel 132 and is pushed in the trailing
direction when tool
110 is cocked as barrel 132 is pushed in the trailing direction by muzzle 118,
as described
above. Cocking rod 162 includes a rotary seer (not shown) which engages firing
pin 164
in the trailing direction so that firing spring 166 is compressed, as shown in
IFTG. 7.
When trigger 160 is pulled by tb.e operator, cocking rod 162 is rotated so
that the rotary
seer is rotated out of the way of firing pin 164 so that the rotary seer is no
longer
engaging firing pin 164. When the rotary seer is no longer engaging firing pin
164, firing
spring 166 is free to extend and bias firing pin in the driving direction so
that firing pin
164 can detonate cartridge 113. In the cocked condition, shown in. FIG. 16, an
arrn 162a
at the forward end of cocking rod 162 has moved into alignment with a link 163
mounted
9
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
in a trigger support 165_ When trigger 160 is depressed, link 163 is displaced
upwardly.
to engage arm 162a and thereby rotate cocking rod 162 in order to release the
rotary seer
frorn engagement with firing pin 164. The firing pin 164 is then released to
be driven
forwards to detonate the cartridge 113 in firing chamber 134 of barrel 132.
100461 Continuing with FIG. 7, an exemplary cartridge strip 111 contains a
plurality
of explosive cartridges 113 arranged in a row. Each cartridge 113 of cartridge
strip 111
contains a predetermined amount of explosive powder which is detonated by
firing pin
164 during firing of tool 110. A cartridge 113 can only be detonated once by
firing pin
164, because once the explosive powder has been detonated, it is used up and
must be
replaced by a second cartridge 113b. Cartridge strip 111 allows a pluralaty of
cartridges
113 to be fed to tool 1.10, so that an operator may fire tool 110 several
times without
having to reload explosive powder cartridges 113. Cartridge strip 111 is
indexed by an
advancing mechanism 154 through a cartridge strip channel 120. Cartridge strip
channel
120 extends in the indexing direction through handle 112 and housing so that
cartridges
113 can be indexed into and out of firing chamber 134.
10047] Trigger 160 is also associated with advancing mechanism 154 for
automatically indexing cartridge strip 111. Advancing mechanism 154 is
operationally
associated with trigger 160 so that when tri.gger 160 is in its first pre-
firing position,
advancing mechanism 154 is in a first position, as shown in FIG. 8, and when
telgger 160
is pulled by an operator into a second fired position, advancing mechanism 154
is moved
into a second position, as shown in FIG. 9.
[0048] Turning to F1GS. 8 and 9, advancing mechanism 154 includes an advancing
lever 170 and an advance link 150. Advance link 150 is operationally
associated with
trigger 160 so that when trigger 160 is in afrst pre-firing position, shown in
FIG. 8,
advance link 150 is in a first position, and when trigger 160 is pulled by an
operator into
a second fired position, shown in FIG. 9, advance link 150 is biased into a
second
position. Advancing lever 170 indexes cartridge strip I 11 in the inde7cing
direction and is
cammingly engaged with advance link 150, as described below, so that when
advance
link 150 is in a first position, advancing lever 170 is also in a first
position, and when
advance link 150 is biased into a second position, advancing lever 170 is
pivoted into a
second position, as described below.
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
100491 Adti ancing lever 170 is pivotally connected to too1110 by a pivot pin
172 so
that advancing lever 170 can pivot between a first position, shown in FIG. 8,
and a
second position, shown in FIG. 9. In one embodiment, shown in FIG, 6, pivot
pin 172 is
connected to a firing mechanism housing 168 so that advancing lever 170 is
pivotally
connected to mechanism housing 168. However, advancing lever 170 can be
pivotally
connected to tool housing 122 without varying from the broad scope of the
present
invention. A retaining clip 173 is connected to pivot pin 172 in order to
prevent
advancing lever 170 from becoming disengaged with pivot pin 172 during
operation of
too1110.
j00501 Continuing with FIG. 8, advancing lever 170 includes a strip engagement
portion 171 for engaging and indexing cartridge strip 111, a pivot hole for
receiving pivot
pin 172, and a lever camnxing portion 186 for cammingly engaging with advance
link
150, described below. A retention clip 173 is also included to ensure that
advancing
lever 170 remains pivotally connected, via pivot pin 172, to tool 110 during
operation of
tool 110.
[0051] In a preferred embodiment, strip engagement portion 171 is located
generaliy
at a driving end of advancing lever 170, pivot pin 172 is generally centered
along
advancing lever 170 and lever camnning portion 186 is located generally at a
trailing end
of advancing lever 170, wherein strip engagement portion 171 and lever
camuniaig portion
186 are on opposite sides of the pivot hole. However, advancing lever 170 is
not limited
to this configuration. An alternative embodiment (not shown) includes the
pivot hole
located generally at the trailing end and the camming portion generally
centered along the
advancing lever. The alter.aative advancing mechanism can still operate to
index
cartridge strip 111, as described below.
[00521 Tarning to FIG. 6, one em.bodiment of strip engagement portion 171 of
advancing lever 170 is shown. Strip engagement portion 171 includes a pawl 176
connected to advancing lever 170 and a spring 177 for biasing pawl 176 toward
cartridge
strip 111. Pawl 176 is pivotally connected to advancing lever 170 with a pin
1.78 so that
pawl 176 can pivot in and out of notches 180 in cartridge strip 111 in a
ratcheting motion,
described below. In one embodiment, spring 177 is a flexible rod which has a
first end
188 retained by advancing lever 170 and a second end 190 engaged with
paw117Ca,
11
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
wherein a boss 179 connected to advancing lever 170 bends spring 177 between
first end
188 and second end 190 so that spring 177 provides a biasing force against
pawl 176 to
bias pawl into a notch 180 of cartridge strip 111. When advancing lever 170 is
in its first
position, strip engagement portion 171 is in an upper first position, shown in
FIG. 8, and
when advancing lever 170 pivots to its second position, strip engagement
porCion 171
moves to a lower second position, shown in FIG. 9.
100531 It will be understood that during the movement of advancing lever 170
and
pawl 176 which occurs during firing of tool 110, cartridge strip 111 is fixed
in position as
the operative cartridge 113 is held within .firing chamber 134 at the rear of
barrel 132
with the breach block 133, shown in FIG. 14, being closed. Af1er firing, the
breach is
opened by forwards movement ofbarrel 132 and breach block 133 to release the
spent
cartridge 114. The trigger 160 is also released and moves forwardly under the
bias of
trigger spring 161.. This forwards movement is translated into movement of the
advance
Iink 150 and, via cani pin 174, and cam slot 156, there results an upwards
movement of
the forward end of the ad.vancing lever 170; due to the engagement of the pawl
176 with
the adjacent notch 180 of the cartridge strip 111, the cartridge strip 8
itself will also be
indexed to present the next cartridge 113 at the operative firing position.
[0054] The spring 177 which biases pawl 176 and which is deflected during the
advancing movement of the advancing lever 170 will result in an increased
trigger force
and this can also be readily controlled to ensure reliability of the action of
pawl 176
without unduly increasing the trigger force needed to be applied to fire the
tool. This
spring biasing enables the spring force applied to pawl 176 to be adjusted
simply by
selection of spring wire of appropriate characteristics.
[00551 Returning to FIG. 6, one einbodiment of lever camrning portion 186
includes
a ratnped cam slot 156, which corresponds to a cam pin.174 on advance
l.inlÃ150.
However, in an equivalent alternative embodiment (not shown) the cam pin is
located on
the advancing lever and the cam slot is in the advance link. Cam slot 156
extends
generally along advancing lever 170 and is located generally at a trailing end
192 of
advancing lever 170. Cam slot 156 includes a ramped leading leg 194 and a
trailing leg
196 aligned essentially parallel to advancing lever 170, wherein cam slot 156
is oriented
so that it is generally convex in the indexing direction, with an angle ?,
shown in FIG. 8,
12
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanisxn
For Fastener Driving Tool"
between leading leg 194 and trailing leg 196, In one embodiment, angle ? is
between
about 110 and about 1501, andpreferably about 135 .
100561 The length of leading leg 194 and trailing leg 196 are generally equal
to each
other, with each leg 194,196 having a length between about 0.220 inches and
about 0.240
inches; with a preferred length of leading leg 194 being about 0.115 inches
and a
preferred length of trailing leg being about 0.115 inches. The width of cam
slot 156
should be slightly larger than the diameter of cam pin 174 so that caan pin
174 fits within
cam slot 156 within a close, predeterrnined tolerance. In one ernbodirnent,
cam pin 174
has a diameter of about 0.098 inches, and cam slot 156 has a width of about
0.104 inches.
[0057] It is necessary to "tune" the mechanism so that the trigger action
provides a
comfortable feel. To an extent this can be accomplished by appropriate shaping
of the
cam slot 156, which can be determined empirically. The cam slot 156 provides a
degree
of lost tnotion towards the end of the depression stroke of the trigger 160
whereby the
indexing movement of the advancing lever 170 occurs during the initial and
intermediate
parts of the movement of the trigger 160.
100581 Cam slot 156, and particularly trailing leg 196, should have a length
sufficient
to allow cam pin 174 to continue to slide along trailing leg 196 even after
advancing lever
170 has pivoted from the first position to the second position so that strip
engagement
portion 171 is engaged with a lower second notch 180b in cartridge strip 111.
When cam
pin 174 is allowed to continue to slide, it prevents "dead stop" of the
trigger so that an
operator does not feel a hard stop of trigger 160 when strip engageinent
portion 171
engages with a notch 180 in cartridge strip I11, as described below, but
rather caxt
continue to pull trigger 160 in the trailing direction for a time after
advancing mechanism
154 has moved from its first position to its second position.
[0059] Turning to FIG. 8, advance link 150 is operationally associated with
trigger
160 so that when trigger 160 moves in the trailing direction from its first
pre-firing
position to its second fired position when an operator pulls the trigger 160,
advance link
150 also moves from a first position to a second position. Advance link 150
includes a
trigger engagement portioii 198 for engaging with trigger 160, and a link cam
portion. 200
for canuningly engaging with advancing lever 170. In one embodiment, trigger
engagement portion 198 is located generally at a driving end 202 of advance
link 150,
13
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Llriving Tool"
and link cam portion 200 is located generally at a trailing end 204 of advance
link 150.
[0060] In one embodiment, shown in FIG. 6, trigger engagement portion 198
includes
a flange 206 having a slot 208. Advance link 150 is connected to a trailing
end 210 of
trigger 160 with a screw 212, shown in FIG. 8, that extends tlasough slot 208
and into
trigger trailing end 210, wherein screw 212 is tightened so that flange 206 is
tightly flush
against trigger 160.
[0861] As part of the tuning of the indexing system, it is necessary to ensure
that the
movement of the advancing lever 170 during trigger depression moves the
paw1176 into
the next notch 180 of cartridge strip 111 only when. trigger 160 has been
depressed
sufficiently to fire the cartridge 113, so as to avoid a mis-ind.exin.g
situation which could
otherwise arise if the trigger 160 is only partially depressed, While to an
extent this is
also determined by the shaping of the cam slot 156, however manufacturing
tolerances
can adversely influence the required tin-dng between trigger depression and
indexing
movement of lever 170. In order to account for tolerances which can also arise
during
manufacture, the forward end of link 150 is connected to trigger 160 by a
screw threaded
adjustable mounting which can adjust the relative point of attachment of the
forward end
of link.150 in a fore-aft direction relative to trigger 160. This adjustable
mounting is
shown in greater detail in FIGS. 17A and 17B and comprises a set screw 212
mounted
within trigger 160. Set screw 212 is rotatable to effect fore-aft adjustment
of the
mounting position of flange 206 of link 150 as can be seen from a compression
between
FIGS. 17A and 17B and is lockable in the set position by means of a lock nut
213. As a
result of this adjustment facility, at the time of assembly of the tool link
150 can be
adjusted to ensure that the fiall. indexing movement of lever 170 can only
take place when
trigger 160 has been depressed sufficiently to fire the tool.
100621 Advance link 150 is guided by a guide (not shown) in tool 110 so that
advance
link 150 remains generally parallel to axis 146 when advance link 150 is moved
from its
first position to its second position. In one embodiment, shown in FIGS. 5 and
8,
advance link 150 includes a bent leading portion 214 and a straight trailing
portion 216,
Bent leading portion 214 is adjacent to flange 206 in the trailing direction.
The shape of
bent leading portion 214 is chosen to allow advance link 150 to fit in the
tight space
within tool housing 122 so that advancing mechanism 154 can operate in a small
space.
14
CA 02441171 2003-09-17
'Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
Straight trailing portion 216 remains generally parallel to axis 146 due to
the guide.
100631 Returning to FIG. 8, in one embodiment, link cam portion 200 includes a
cam
pin 174 located generally at trailing end 204 of advance link 150 and
extending
outwardly away from an outer surface 216 of advance link 150. An alteznative
embodiment (not shown) includes cam pin 174 extending inwardly from an inner
surface
of advance link 150. In another alternative (not shown), as described above,
link cam
portion 200 could instead include a cam slot that corresponds to a cam pin
located on
advancing lever 170.
[00641 As described above, advance link 150 moves generally parallel to axis
146 so
that cam pin 174 essentially moves in a straight line in the trailing
direction when
advance link ISO is biased from its first position to its second position by
trigger 160.
Cam pin 174-siides along cam slot 156, as described below, to cause advancing
lever 170
to pivot about pivot pin 172.
[00651 Continuing with FIG. 8, advancing mechanism 154 is designed so that an
operator does not have to manually perform any set of tasks to index cartridge
strip 111.
Pulling trigger 160 actuates firing mechanism 130, as described above, as
trigger 160 is
moved from its first pre-firing position to its second fired position.
Advancing
mechanism 154 provides a link between trigger 160 and strip engagement portion
171 so
that indexing of cartridge strip 111 is automatically performed by the
movement of
trigger 160.
10066] Continuing with FIG. 8, when trigger 160 is in the first position
before an
operator puills trigger 160, advance link 15f3 is located in the first
position wherein
advance link 150 is in its most forward position in the driving direction.
When advance
link is in the first position, caxn pin 174 is generally at the driving end of
leading leg 194
of cam slot 156 so that advancing lever 170 is in its first position with
strip engagement
portion 171 in its upward position.
[0067] When trigger 160 is pulled by an operator, advance link 150 is biased
from the
first position, shown in FIG. 8, in the trailing direction to the second
position, shown in
FIG. 9. Advance link 150 remains aligned essentially parallel to axis 146 so
that cam pin
174 is biased essentially strait in the trailing direction. As cam pin 174
moves in the
trailing direction, cam pin 174 comes into contact with and slides along an
upper surface
CA 02441171 2003-09-17
"Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
218 of leading leg 194 of cam slot 156. As cam pin 174 continues to move in
the trailing
direction, the ramped orientation of leading leg 194 of caan slot 156 forces
the trailing
end 192 of advancing lever 170 to pivot upwards, so that the entire advancing
lever 170
pivots in a counterclockwise direction in FIG. 9. This rotation causes strip
engagement
portion 171 to be pivoted downward so that strip engagement portion 171
disengages
from a first notch 180a in cartridge strip l 11, and engages with a lower
second notch
180b, shown in FIGS. 10-12.
[00681 As shown in FIG. 10, when strip engagement portion 171 is in the first
upward position, paw1176 is engaged within an upper first notah. 180a so that
an upper
first cartridge 113a is aligned with axis 146 so that first cartridge 1 13a is
within a firing
chamber 134 (shown in FIG. 7). When trigger 160 is pulled by an operator,
first
cartridge 113a is detonated by fsring mechanism 130 so that cartridge 113a
becomes a
spent cartridge i 14 shown in FIG. 11. At the same time trigger biases advance
link 150
in the trailing direction, and advancing lever 170 is rotated from the first
position to the
second position, as shown in FIG. 9 and descrs bed below.
(0069] When advancing lever 170 is rotated, strip engagement portion 171 is
rotated
from its upward first position, shown in FIG. 10, to its downward second
position, shown
in FIG. 12. When strip engagement porfion.171 begins to be biased downward, a
bottom
surface 222 of first notch I80a pushes against a sloped bottom surface 224 of
pawl 176,
urging paw1176 against the bias of spring 177, and causing pawl 176 to pivot
out of first
notch 180a on pin 178, as shown in FIG. 1 l. As strip engagement portion 171
continues
to be biased downward from the first position to the second position, pawl 176
slides
along side surface 226 of cartridge strip 111.
100701 Turning to FIG. 12, eventually strip engagement portion 171 is biased
to its
downward second position, so that pawl 176 encounters a lower second notch
180b,
wherein second notch 180b is located directly below first notch 180a on
cartridge strip
I 11. Second notch 180b corresponds to a second cartr tdge 113b located
directly below
f3rst cartridge 113 a. Spring 177 biases pawl 176 into second notch 180b so
that a side
surface 228 of pawl 176 is biased against side surface 230 of'second notch
180b.
100711 When trigger 160 is released, trigger spring 161 biases trigger 160
from its
second position in the driving direction back towards the pre-firing first
position.
16
CA 02441171 2003-09-17
. "Cartridge Strip Advancing Mechanism
For Fastener Driving Tool"
Advance link 150 is associated with trigger 160 so that advance link 150 is
also biased
from the second position in the driving direction to the first position. As
cam pin 174 is
moved along with advance link 150 in the driving direction, cam pin 174 slides
farst
along trailing leg 196, and then up sloped leading leg 194 where cam pin 174
contacts a
bottom surface 220 of leading leg 194, pushing trailing end 192 of advancing
lever 170
downward and pivoting advancing lever 170 from the second position to the
first
position, or in a clockwise direction in FIG. 8.
[00721 As advancing lever 170 pivots from the second position in FIG. 12 to
the first
position in FIG. 13, strip engagement portion 171 moves upwardly, causing a
top surface
232 of pawl 176 to contact an upper surface 234 of second notch 180b. As strip
engagement portion 171 continues to move upward, top sutface 232 of paw1176
engages
upper surface 234 of second notch 180b so that pawl 176 biases cartridge strip
111
upwardly, indexing the spent first cartridge 113a out of firing chamber 134
and indexing
second cartridge 113b into firing chamber 134 so that tool l 10 is ready to
fire again.
[0073] The operator can now pull trigger 160 again, causing fuing inechanism
130 to
;..
detonate second cartridge 113b and causing advancing mechanism 154 to move
strip
engagement portion 171 from its upward position, with paw1176 engaged within
second
notch 180b; to its downward position, with pawl 176 engaged within a third
notch 18Oc.
The operator can then release trigger 160, allowing advancing rnechanism 154
to return
strip engagement portion 171 to its first position so that paw1176 can engage
third notch
1 SOc and index a third cartridge 113c into firing chamber 134. This process
may be
repeated several times until cartridge strip l 11 runs out of cartridges 113
that may still be
fired.
100741 It is important that the trigger is unable to be depressed until the
tool is ready
to be fired as depression of the trigger will result in movement of advancing
mechanisan.
154, resulting in mis-indexing of strip 111. For this reason, trigger support
165 can carry
a trigger lock lever 167 which normally engages a rear abutment edge, of
trigger 160 (see
FIG. 15) to prevent its depression. Trigger lock lever 167 includes an
upwardly
extending release arm 167a which is engaged by a projection at the rear of
barrel 132 on
cocking of too1110 to pivot trigger lock lever 167 out of its locking position
(see FIG. 5)
and thereby pernut depression of trigger 160 which results in iiring of tool
110 and also
17
CA 02441171 2007-07-20
the described downward indexing movement of indexing lever 170 and associated
pawl 176. An
example of a trigger lock is disclosed in Australian Provisional Application
2002951660,
published October 10, 2002 in the Australian Patent Office, the disclosure of
which may be
referred to for further details.
[0075] The inventive fastener driving tool of the present invention provides
an improved
advancing mechanism for the indexing of a strip of explosive powder cartridges
through a
cartridge strip channel. The advancing mechanism provides automatic indexing
of the cartridge
strip caused by the motion of the trigger used to fire the tool so that once a
cartridge is used, a
fresh cartridge is moved into place so that the tool is automatically ready to
fire without requiring
an operator to manually advance the cartridge strip, or to manually perform
tasks that advance
the cartridge strip. The advancing mechanism also prevents "dead stop" of the
trigger, helping
to improve operator comfort due to the repetitive task of pulling the trigger.
[0076] The present invention is not limited to the above-described
embodiments, but should be
limited solely by the following claims.
18
