Cartridge retaining means for a hammer-activated powder-actuated fastening tool

A hammer-actuated fastening tool utilizing a powder cartridge for driving a fastener into a workpiece upon discharge of the cartridge includes a retainer clip for maintaining the cartridge in its operative position within the tool for discharge of the cartridge. The tool includes a housing within which a fastener is positionable, a cartridge-holding body supported within the housing defining a bore within which a cartridge is operatively positionable, and an elongated firing pin for transferring the impact of a hammer to the cartridge for discharging the cartridge. A guide member body is positioned about the firing pin for guiding the firing pin relative to the cartridge-holding body from a first position to a second position at which the impact of the hammer is transferred to a cartridge positioned within the cartridge-holding body. The retainer clip is attached to the guide member body so as to be interposed between the firing pin and a cartridge positioned within the bore of the cartridge-holding body.

BACKGROUND OF THE INVENTION 
This invention relates generally to hammer-activated, powder-actuated 
fastening tools and relates, more particularly, to such fastening tools 
which utilize a powder cartridge for providing, upon discharge of the 
cartridge, the driving power applied to a fastener. 
The tool with which this invention is concerned includes an elongated 
housing within which a fastener, such as a nail or stud, is positionable, 
cartridge-holding means defining a bore within which a powder cartridge is 
operatively positionable, and an elongated firing pin for transferring the 
impact of a hammer to the cartridge for the purpose of discharging the 
cartridge. The tool also includes means for guiding the firing pin 
relative to the cartridge as the pin is moved from a first position at 
which the forward end of the firing pin is spaced from the cartridge to a 
second position adjacent the cartridge. By striking the rear end of the 
firing pin with a hammer, the firing pin moves from its first position to 
its second position to thereby transfer the impact of the hammer to the 
cartridge through the forward end of the pin. An example of a fastening 
tool of this class is shown and described in U.S. Pat. No. 4,025,029. 
Commonly, such a tool includes no means for ensuring that the cartridge, 
once placed within the bore of the cartridge-holding means, is maintained 
in its desired position prior to discharge. Consequently, the cartridge 
may back out of the bore or otherwise shift in position relative thereto 
so as not to be properly seated within the bore when the cartridge is 
discharged. If the cartridge is discharged when improperly seated, the 
spent cartridge may jam within the bore rendering subsequent removal of 
the cartridge difficult. Of course, unless the spent cartridge is removed 
from the bore, the tool cannot be re-used. 
Accordingly, it is an object of the present invention to provide a tool of 
the aforedescribed class having new and improved means for maintaining a 
powder cartridge in a properly seated position within the tool prior to 
discharge of the cartridge. 
Another object of the present invention is to provide such a tool including 
means for ensuring that the cartridge is positioned in its proper position 
within the tool prior to discharge so that the cartridge is less likely to 
jam within the tool following discharge of the cartridge. 
Yet another object of the present invention is to provide such a tool which 
is uncomplicated in construction and effective in operation. 
SUMMARY OF THE INVENTION 
This invention resides in a hammer-actuated fastening tool utilizing a 
powder cartridge for driving a fastener into a workpiece upon discharge of 
the cartridge. The tool includes a housing within which a fastener is 
positionable, cartridge-holding means supported within the housing 
defining a bore within which a cartridge is operatively positionable, and 
elongated firing means for transferring the impact of a hammer to the 
cartridge for discharging the cartridge. The firing means has a rear end 
for receiving the impact of a hammer and an opposite forward end, and the 
tool includes means for guiding the firing means relative to the 
cartridge-holding means from a first position to a second position at 
which the impact of the hammer is transferred to a cartridge positioned 
within the cartridge-holding means through the forward end of the firing 
means. 
The improvement comprises retaining means supported within the housing for 
maintaining the cartridge in its operative position within the bore of the 
cartridge-holding means until discharged. Because the cartridge is 
maintained in its operative position by the retaining means, the cartridge 
is prevented from backing out of the bore or otherwise shifting in 
position relative thereto so as not to be properly seated within the bore 
when the cartridge is discharged.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
Turning now to the drawings in greater detail and considering first FIG. 1, 
there is illustrated a hammer-activated, powder-actuated fastening tool 
20, a fastener 22 of the type intended to be driven by the tool 20 into a 
workpiece and a powder cartridge 24 for providing the power with which the 
fastener 22 is driven into the workpiece. The tool 20 is elongated in 
shape and has an end 28 against which a hammer or similar tool (not shown) 
is struck during use of the tool 20 and an opposite end 30 from which the 
fastener 22 is driven from the tool 20 and into the workpiece. In 
preparation of the tool 20 for use, the cartridge 24 is loaded within the 
tool 20 into a position illustrated in solid lines in FIG. 5 and the 
fastener 22 is inserted head-end-first into the tool end 30 as shown in 
FIG. 5. The tool 20 is then supported with a hand adjacent a workpiece 32 
(FIG. 6) so that the tool end 30 engages the workpiece 32 and so that the 
fastener 22 is directed toward the workpiece location through which the 
fastener 22 is desired to be driven. The tool end 28 is then struck with 
the hammer to discharge the cartridge 24 and so that the gases generated 
by the discharge of the cartridge 24 drives the fastener 22 into the 
workpiece 32. 
As illustrated in FIG. 2, the fastener 22 suitable for use in the tool 20 
is an assembly including a nail 34 having a head 36 and a shank 38 and 
including a guide member 40 secured about the nail 34. As best shown in 
FIG. 3, the guide member 40 includes a body of elastomeric material, such 
as plastic, having a central portion 42 having an opening 44 through which 
the shank 38 of the nail 34 is positioned and a plurality of 
radially-extending fins 46 regularly spaced about the central portion 42. 
The guide member 40 is sized so that its overall diameter is slightly 
greater than the inner diameter of the tool end 30. Therefore, upon 
insertion of the fastener 22 within the tool end 30 to the position 
illustrated in FIG. 5, the fins 46 of the guide member 40 are flexed 
slightly inwardly so that the fastener 22 is snugly retained within the 
tool end 30 by the flexed condition of the guide member 40. 
As illustrated in FIG. 4, the powder cartridge 24 suitable for use in the 
tool 20 includes a casing 48 containing an amount of powder and primer and 
is commonly referred to as a rim-fire cartridge. The casing 48 has a nose 
end 50 and a rear end 52 having a rim, and the primer is retained within 
the casing 48 adjacent the rim so that upon exposure of the rim to an 
impact sufficient to deform the rim, the cartridge 24 discharges. Upon 
discharge of the cartridge 24, the gases generated as a result thereof 
abruptly exit the nose end 50 of the casing 48 for the purpose of driving 
the fastener 22 from the tool end 30. 
With reference to FIGS. 5-7, the tool 20 includes a tubular housing 
assembly 56 within which the fastener 22 is positioned for use of the tool 
20. The housing assembly 56 includes a main tube 58 and a muzzle tube 60 
having an end portion which is fixedly secured within an end portion of 
the main tube 58 as illustrated in FIG. 5 so that a major portion of the 
muzzle tube extends from the main tube 58. The muzzle tube 60 provides the 
end 30 of the tool 20 within which the fastener 22 is positioned for use 
of the tool 20, and the main tube 58 includes an annular groove 62 in its 
outer surface within which an end of a spring is retained. The main tube 
58 also includes a linear groove 64 extending along one side thereof for a 
purpose apparent herein. 
With reference still to FIG. 5, the tool 20 also includes cartridge-holding 
means 66 for holding the cartridge 24 within the tool 20 for firing. In 
the depicted tool 20, the cartridge-holding means 66 includes a body 68 of 
material, preferably steel, which is fixedly secured within the main tube 
58 adjacent the end thereof opposite the muzzle tube 60 and includes a 
central bore 70 for accepting a cartridge 24 inserted nose-end-first 
therein. The bore 70 includes sections which are sized to accommodate the 
different sized sections of the cartridge 24 and an enlarged entrance 
section sized to accept the lip of the rim of the cartridge casing 48. In 
the interests of the present invention, a cartridge 24 is operatively 
positioned within the bore 70 when the cartridge 24 is seated within the 
bore 70 so that the lip of the casing 48 is positioned in abutting 
relationship with the cartridge-holding body 68. In its operative position 
within the bore 70, a portion of the rim of cartridge 24 extends slightly 
beyond the entrance of the bore so that the rim is exposed for firing 
purposes. Upon discharge of the cartridge 24, gases which are forced to 
exit the nose end of the cartridge 24 exit the cartridge-holding body 68 
through the right end, as viewed in FIG. 5, of the bore 70. 
The tool 20 also includes a piston assembly 72 slidably positioned within 
the housing assembly 56 for transmitting the force of the gases exiting 
the cartridge casing 48 to the fastener 22. The piston assembly 72 
includes an elongated head 74 and a rod 76 integrally joined together in 
an end-to-end manner. The head 74 includes a plug-like body 78 having a 
face end 80 which generally faces the cartridge-holding body 68 and outer 
dimensions which are sized to be received by the interior of the main tube 
58. The piston body 78 also includes an annular groove for accepting a 
wire ring 84 positioned thereabout to thereby seal the space between the 
body 78 and the interior of the main tube 58. The rod 76 is slidably 
positioned within the interior of the muzzle tube 60 and, accordingly, has 
a diameter which is slightly smaller than that of the inner diameter of 
the muzzle tube 60. 
The piston head 74 also includes a central protuberance 86 extending 
axially from the face end 80 for acceptance by the bore 70 of the 
cartridge-holding body 68. Upon return of the piston assembly 78 to a 
ready-to-fire position within the housing assembly 56 following discharge 
of the cartridge 24, the protuberance 86 enters the bore 70 of the 
cartridge-holding body 68 and urges the spent casing 48 from the bore 70 
through the opposite end of the cartridge-holding body 68. 
When the piston assembly 72 is positioned within the housing assembly 56 in 
a ready-to-fire position as is shown in FIG. 5, the piston head 74 is 
slidably positioned within the main tube 58 so that its face end 80 is 
positioned in relatively close proximity to the cartridge-holding body 68 
and the rod 76 extends a relatively short distance into the muzzle tube 
58. The interior space of the muzzle tube 58 left unoccupied by the rod 76 
is of sufficient size to accommodate the fastener 22 inserted therein. 
Upon discharge of a cartridge 24 within the tool 20, the piston assembly 
72 moves along the housing assembly 56 to an extended position as 
illustrated in phantom in FIG. 7 where the advance of the piston assembly 
72 along the length of the housing assembly 56 is halted by the surface of 
the workpiece 32. The assembly 72 is prevented from being totally removed 
from the housing assembly 56 due to the large size of the piston head 74 
in relation to the inside dimension of the muzzle tube 60. 
With reference again to FIG. 5, the tool 20 includes a guide assembly 90 
connected to the housing assembly 56 and adapted to be gripped by the hand 
during use of the tool 20. The guide assembly 90 includes a sleeve 92 
positioned about the main tube 56 and a guide member 94 positioned within 
the sleeve 92. The sleeve 92 includes an opening 88 provided along a side 
thereof and is positioned about the main tube 58 to accommodate a sliding 
movement of the sleeve 92 relative to and along the length of the main 
tube 58. A spring lock 96 is affixed within the sleeve 92 and is partially 
positioned within the linear groove 64 provided in the side of the main 
tube 58 to prevent the removal of the sleeve 92 from the main tube 58 and 
to prevent the rotation of the sleeve 92 about the main tube 58. As the 
sleeve 92 is slidably moved along the length of the main tube 58, the 
spring lock 92 is guided along the linear groove 64. A compression spring 
98 is fixed at one end within the annular groove 62 of the main tube 58 
and positioned about the main tube 58 so as to act between the sleeve 92 
and the tube 58. When using the tool 20, the spring 98 requires that the 
guide assembly 90 be urged along the length of the housing assembly 56 
with a predetermined, or minimum, amount of force to ready the tool 20 for 
firing. 
With reference to FIGS. 8 and 9, the guide member 94 includes a body 100 
constructed, for example, of a zinc alloy and having two opposite ends 102 
and 104. The body 100 of the guide member 94 includes a cylindrical end 
portion 106 adjacent its end 102 and having an outer diameter which 
generally corresponds with the outer diameter of the sleeve 92 and a 
cylindrical end portion 108 adjacent its end 104 of reduced diameter. More 
specifically, the reduced end portion 108 is sized to be closely received 
by the sleeve 92 of the guide assembly 90 as shown in FIG. 5. The reduced 
end portion 108 is provided with a pair of annular grooves 110 and is 
joined to the sleeve 92 by means of an amount of material of the sleeve 92 
which has been machine-rolled so as to be received by the annular grooves 
110. 
The guide body 100 also includes a central passageway 112 extending between 
the body ends 102, 104. The passageway 112 includes a first enlarged 
section 114 opening out of the body end 102 and terminating in a shoulder 
116 and a second enlarged section 118 opening out of the opposite body end 
104 and terminating in a shoulder 120. Extending between the shoulders 116 
and 118 is a central bore section 122 having a smaller diameter than that 
of the enlarged sections 114, 118. 
To facilitate the grasping of the guide assembly 90 for use of the tool 20, 
the tool 20 includes a grip 124 fixedly secured about the guide member 94 
and an adjacent portion of the sleeve 92. The grip 124 is comprised of an 
elastomeric material and has an end 126 adjacent the tool end 28 which is 
open for a reason apparent herein. 
The guide assembly 90 is slidably movable relative to and along the length 
of the housing assembly 56 between a retracted condition as illustrated in 
FIG. 5 and a ready-to-fire condition as illustrated in FIG. 6. In the FIG. 
5 retracted condition, the guide member body 100 is spaced a considerable 
distance from the cartridge-holding body 68 and the opening 88 provided 
along a side of the sleeve 92 provides access to the cartridge-holding 
body 68 for the purposes of placing a cartridge 24 within the bore 70 of 
the body 68 and accommodates removal of a spent casing 48 following 
discharge of the cartridge 24. In the FIG. 6 ready-to-fire condition, the 
end 104 of the guide member body 100 is positioned adjacent the 
cartridge-holding body 68 so that the passageway 112 of the guide body 100 
is positioned in registry with the rear end of the cartridge 24 positioned 
within the bore 70. 
The tool 20 also includes firing pin means, generally indicated 130, for 
transferring the impact force of a hammer to the cartridge 24 for the 
purpose of discharging the cartridge 24. In the depicted tool 20, the 
firing pin means 130 includes a bolt 132 having a head 134 and a threaded 
shank 136 and includes a nut 138 threadably secured upon the shank 136. 
The bolt 132 is positioned within the body 100 of the guide member 94 so 
that its shank 136 is loosely received by the passageway 112 of the body 
100 and so that the head 134 is positioned within the enlarged section 118 
provided adjacent the body end 104. In the depicted tool 20, a sleeve 
member 140 is positioned within the passageway 112 and the bolt shank 136 
extends through the sleeve member 140 so that the walls of the sleeve 
member 140 are disposed between the walls of the passageway 112 and the 
surface of the shank 136. The nut 138 is tightened upon the shank 136 and 
against the end of the sleeve member 140. During use of the tool 20, the 
bolt 132 is slidably movable relative to and along the length of the 
passageway 112 between a retracted position, as illustrated in FIG. 6, at 
which the bolt head 134 is positioned adjacent the shoulder 120 and an 
extended position, as illustrated in FIG. 7, at which the head 134 is 
positioned adjacent the end 102 of the guide member body 100. 
The tool 20 also includes means, generally indicated 144, for biasing the 
bolt 132 from its FIG. 7 extended position toward its FIG. 6 retracted 
position. In the depicted tool 20, the biasing means 144 is in the form of 
a compression spring 146 positioned about the shank 136 of the bolt 132 so 
that one end of the spring 146 engages the nut 138 and the other end of 
the spring 146 engages the shoulder 116 of the guide member body 100. 
Accordingly, the spring 146 is sized to loosely accept the sleeve member 
140 to be received by the enlarged section 114 of the guide member body 
100. 
The spring 146 is compressed between the nut 138 and the shoulder 116 so 
that the spring 146 continually urges the head 134 of the bolt 132 toward 
its retracted position of FIGS. 5 and 6. Preferably, the strength of the 
spring 146 is preselected so that by tightening the nut 138 upon the 
sleeve member 140, the spring 146 exerts a desired preset force upon the 
bolt 132. It is preferred that this preset force is sufficient to minimize 
inadvertent discharge of the cartridge 24, if, for example, the tool 20 is 
dropped upon a floor, but it will be understood that this preset force 
must be overcome by the impact of a hammer during use of the tool 20 
before the bolt head 134 can be moved from its retracted position of FIGS. 
5 and 6 to its extended position of FIG. 7. 
The tool 20 also includes retaining means, generally indicated 150, for 
maintaining the cartridge 24 in its operative position within the bore 70 
of the cartridge-holding body 68 for use of the tool 20. In the tool 20, 
the retaining means 150 is in the form of a retainer clip 152 attached to 
the end 104 of the guide member body 100 so as to span the passageway 
opening provided therein. As best shown in FIGS. 8-10, the retainer clip 
152 includes a thin platen portion 154 which is circular in form and two 
tabs 156 which are joined to the platen portion 154 on opposite sides 
thereof. For securement of the clip 152 to the guide member body 100, the 
body 100 is provided with a pair of indentations 158 disposed on opposite 
sides thereof and adjacent the body end 104, and the tabs 156 cooperate 
with the indentations 158 to join the clip 152 to the body 100. More 
specifically, the tabs 152 are bent out of the general plane of the platen 
portion 154 into an L-shaped configuration as shown in FIG. 9 so that by 
urging the clip 152 over the body end 154 so that the tabs 156 move along 
the sides of the body 100, the tabs 152 move into snap fit relationship 
with the indentations 158 to thereby lock the clip 152 in its desired 
position upon the body 100 as illustrated in FIG. 8. 
The clip 152 is constructed of a resiliently flexible material, such as 
annealed spring steel (e.g., C1075 cold rolled steel) and has a thickness, 
as measured through the platen portion 154, of about 0.015.+-.0.001 
inches. Furthermore, the platen portion 154 possesses a slight concavity 
as a path is traced thereacross so that the platen portion 154 is slightly 
arcuate in shape as viewed in the cross-sectional view of FIG. 9. When the 
guide member body 100 is positioned within the tool 20 with the clip 152 
attached thereto, the platen portion 154 of the clip 152 is interposed 
between the cartridge-holding body 68 and the bolt head 134 as shown in 
FIG. 6. 
To use the tool 20, the guide assembly 90 and housing assembly 56 are moved 
relative to one another to the illustrated FIG. 5 position at which the 
bore 70 of the cartridge-holding body is accessible through the opening 88 
provided in one side of the sleeve 92. The cartridge 24 is then placed 
into the bore 70 by inserting the cartridge 24 nose-end-first from a 
position shown, for example, in phantom in FIG. 5, to its operative 
position within the bore 70 as illustrated in solid lines in FIG. 5. A 
fastener 22 is also inserted head-end-first into the muzzle tube 60 to the 
FIG. 5 position where it is retained therein by the aforementioned 
cooperation between the guide member 40 and the inside walls of the muzzle 
tube 60. 
The guide assembly 90 and housing assembly 56 are thereafter moved relative 
to one another to position the guide member body 100 adjacent the rear of 
the cartridge 24 in the ready-to-fire condition illustrated in FIG. 6. The 
tool 24 is thereafter placed against the surface of a workpiece 32, 
illustrated in FIGS. 6 and 7 as comprised of a concrete layer 162 overlain 
by a piece of wood 164, so that the fastener 22 is directed generally 
toward the location on the surface of the workpiece 32 through which the 
nail 34 of the fastener 22 is desired to be driven. As the tool 20 is held 
in position against the workpiece 32 (as the grip 124 is held with one 
hand), the nut-end of the bolt 132 is struck with a hammer or similar tool 
through the open end 126 of the grip 124 so that the bolt head 132 is 
driven against and discharges the cartridge 24. Upon discharge of the 
cartridge 24, gases exiting the cartridge casing 48 force the piston 
assembly 72 relative to and along the length of the muzzle tube 60 to the 
position illustrated in phantom in FIG. 7 so that the fastener nail 34 is 
driven by the piston assembly 72 into the workpiece 32 to the position 
illustrated in phantom in FIG. 7. The guide member 40 of the fastener 22 
is forced to exit the muzzle tube 60 with the nail 34 but is commonly 
crushed between the surface of the workpiece and the head of the nail 34 
as the nail 34 is driven into the workpiece 32. 
It follows that as the guide assembly 90 is moved along the housing 
assembly 56 to the ready-to-fire condition of FIG. 6, the clip 152 is 
moved into engagement with the rear of the cartridge 24 so as to span the 
cartridge 24. The aforedescribed concavity of the platen portion 154 of 
the clip 152 accommodates the small projection of the rim of the cartridge 
24 from the bore 70 and enables the end 104 of the guide member body 100 
to stably abut the edges of the cartridge-holding body 68 prior to the 
exposure of a hammer-applied force to the bolt 132. Thus, the clip 52 
provides a backing for the cartridge 24 prior to discharge so that as long 
as the guide assembly 90 is maintained in its FIG. 6 ready-to-fire 
condition, the cartridge 24 is prevented from sliding or shifting out of 
its operative position within the bore 70 by the clip 152. 
Upon striking of the nut-end of the bolt 132 with a hammer, the bolt 132 
shifts to the position of FIG. 7 at which the head 134 impacts the platen 
portion 154 of the clip 152 and deforms the rim of the cartridge (i.e., 
discharges the cartridge 24) through the platen portion 154. As the bolt 
head 134 deforms the cartridge rim, the platen portion 154 is flexed to a 
relatively flat condition between the bolt head 134 and the cartridge 24 
and exposes the rim of the cartridge 24 to substantially the entire force 
of impact of the bolt head 134 exerted upon the clip 152. Following 
discharge of the cartridge 24 and return of the bolt 134 by means of the 
spring 146 to its FIG. 6 retracted position, the memory of the clip 152 
returns the platen portion 154 of the clip 152 to its unflexed, concave 
condition illustrated in FIG. 6. 
Another advantage provided by the retainer clip 152 relates to the fact 
that as the retainer clip 152 is urged against the cartridge-holding body 
68 as the guide assembly 90 is moved to its ready-to-fire condition, a 
cartridge 24 which has not been properly placed within the 
cartridge-holding body 68 is urged by the retainer clip 152 into its 
operative, seated condition within the bore 70. For example, there is 
illustrated in FIG. 11, a cartridge 24 which has been placed within the 
tool 20 so as to be canted with respect to the longitudinal axis of the 
bore 70. Upon subsequent movement of the guide assembly 90 from its 
retracted (FIG. 5) condition to its (FIG. 6) ready-to-fire condition, the 
retainer clip 152 engages the rear end of the cartridge 24 and urges the 
cartridge 24 into its operative, seated condition illustrated in phantom 
in FIG. 11. It follows that the retainer clip 152 ensures that the 
cartridge 24 is properly seated within the bore 70 of the 
cartridge-holding body 68 prior to discharge of the cartridge 24. 
Following the use of the tool 20, the piston assembly 72 can be returned to 
its FIG. 6 position adjacent the cartridge-holding body 68 by moving the 
guide assembly 90 relative to the housing assembly 56 to its FIG. 5 
retracted position. As the guide assembly 90 is moved in this manner, the 
spring lock 96 cooperates with the piston head 74 to return the piston 
assembly 72 to its FIG. 6 condition as the spring lock is slidably moved 
along the groove 64. Before the spring locks 96 reaches its leftwardmost, 
as viewed in FIG. 5, limit of travel, the central protuberance 86 of the 
piston head 72 extends into the cartridge-holding bore 70 and urges the 
spent cartridge 24 from the bore 70 where it may exit the tool 20 through 
the sleeve opening 88. Since the cartridge 24 is discharged while properly 
seated within the tool 20, the likelihood that the spent cartridge will 
jam within the bore is significantly reduced. With the cartridge casing 48 
removed from the bore 70, the tool 20 is in condition to be prepared for 
re-use. 
It will be understood that numerous modifications and substitutions may be 
had to the aforedescribed embodiment without departing from the spirit of 
the invention. For example, although the retainer clip 152 of the 
aforedescribed tool 20 has been shown and described as being circular in 
shape so as to span the end 104 of the guide member body 100, a retainer 
clip in accordance with the broader aspects of this invention may possess 
an alternative form. For example, there is illustrated in FIG. 12 an 
alternative retainer clip 172 having a platen portion 174 and a pair of 
tabs 176 joined to the platen portion 174 on opposite sides thereof. The 
platen portion 174 is not circular in form as is platen portion 154 of the 
FIG. 10 clip 152 but instead has a pair of opposite side edges 178 which 
are substantially straight and parallel to one another. Accordingly, the 
aforedescribed embodiment is intended for the purpose of illustration and 
not as limitation.