Note: Descriptions are shown in the official language in which they were submitted.
Field Of The Invention
. . . _
This invention relates to fastener-driving toss
in general, and more particularly to powder-actuated
fastener-driving tools.
Background Of The Invention
Fastener-driving tools are well known in the art.
Such tools can generally be classified into two broad
classes of tools, based on their source of driving
power. The first class of tools, sometimes referred
to as fluid-powered fastener-driving tools, depend on
the use of pressurized fluids (e.g., air) to provide
their driving power. Such tools are exemplified by
the following U.S. Patents: 3952398, 404055~, 4122904,
4196833 and 4346831. The second class of tools, some-
times referred to as powder-actuated fastener-driving
tools, depend on the use of explosive cartridges to
provide their driving power. Such tools are in turn
exemplified by the following U.S. Patents: 316~7~4,
3499590, 3552625, 3554425, 3565313 and 3743159.
Unfortunately, existing powder-actuated fastener-
driving tools of the type which are adapted to accept
a strip of charges tend to suffer from a number of
serious problems. Typically, these tools tend to have
a complex construction, so that they are relatively
expensive to manufacture, fairly difficult to
assemble, and prone to mechanical failure. Second, in
many powder-actuated fastener-driving tools, the
exhaust passages used to vent the hot gases of come
bastion from the interiors of the tools are in-
adequate for the task required; as a result, the tools
are relatively noisy, have significant recoil, are
HMH-77
energy inefficient, and/or tend to jam often on
account of the buildup of spent powder within the
tools. Third, none of the existing powder-actuated
fastener-driving tools is capable of using a so-called
"Red" charge cartridge (also known in the industry as
a "Power Level 5" cartridge, or simply a "No. 5"
cartridge) with a light-weight fastener (e.g., a I"
long nail) and still be considered a "low velocity"
tool. In this respect, it is noted that a "low
velocity" tool is one which has a maximum velocity of
300 feet per second measured six feet from the muzzle.
Another problem with many powder-actuated fastener-
driving tools is that they have a construction which
does not allow for easy disassembly in the field so as
to facilitate maintenance. another common limitation
of prior designs is that they cannot be easily adapted
to drive fasteners of differing types and dimensions.
Also existing powder-actuated fastener-driving tools
are typically not easily adapted to be mounted to a
pole assembly or else available pole assemblies for
such tools are inconvenient to use or permit accident
tat firing.
In addition to the aforementioned problems common
to many existing tools, at least one tool of that type
also utilizes a trigger assembly of relatively great
complexity, so that the aforementioned problems of
expense of manufacture, difficulty of assembly, and
tendency towards mechanical failure are exacerbated
In addition, at least one existing powder-actuated
fastener-driving tool utilizes a cam arrangement in
its cartridge advance mechanism which tends to wear
excessively, so that increased maintenance is required
or tool jamming may occur.
Objects Of The Invention
Accordingly, the principal object of the present
invention is to provide a powder-actuated fastener-
driving tool which is specifically adapted to avoid
the foregoing problems which are associated with the
prior art tools.
ore specifically, one of the objects of the pro-
sent invention is to provide a powder-actuated
fastener-driving tool of the magazine type which is
relatively cheap to manufacture, fairly easy to
assemble, reliable in its operation and virtually jam-
free.
Another object of the invention is to provide a
powder-actuated fastener-driving tool which is
equipped with improved exhaust passages for venting
the hot gases of combustion from the interior of the
tool, in order that the tool will be quieter, have
less recoil, be more energy efficient (and hence, more
powerful), and haze less tendency to jam on account of
the buildup of spent powder residue within the
interior of the tool.
Still another object of the invention is to pro-
vise a powder-actuated fastener driving tool which is
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capable of using a so-called "Red" charge cartridge
with a light weight fastener and still be considered a
"low velocity" tool.
Yet another object of the invention is to provide
a powder-actuated fastener-clriving tool which is easy
to disassemble in the field, in order to facilitate
maintenance.
And another object of the invention is to provide
a powder-actuated fastener-driving tool which can be
easily adapted to drive fasteners of differing types
and dimensions.
Yet another object of the invention is to provide
a powder-actuated fastener-driving tool which is
easily adapted for use in conjunction with a pole
asselnbly of superior design so as to form a superior
pole tool.
Still another object of the invention is to pro-
vise a powder-actuated fastener-driving tool having a
trigger assembly which is simple, relatively cheap to
manufacture, fairly easy to assemble, reliable, and
does not cause the tool to jam.
Another object of the invention is to provide a
powder-actuated fastener-driving tool which uses an
improved cam arrangement in its cartridge advance
mechanism, in order that cam wearing will be minimized
and maintenance and tool jamming reduced.
Summary Of The Invention
These and other objects are achieved by the pro-
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sent invention, which comprises a powder-actuated
fastener-driving tool having the following improve-
mints over prior art tools. first, the present invent
lion utilizes a trigger assembly comprising a release
lever pivotal supported for movement toward and away
from the tool's firing mechanism, a torsion spring
yield ably biasing the release lever away from the
firing mechanism, a trigger, and a trigger push rod
coupling the trigger to the release lever so as to
cause the trigger to force the release lever in a
direction to activate the firing mechanism when the
trigger is pulled. Second, the present
invention utilizes a cam in the tool's cartridge
advance mechanism which has a generally rounded upper
surface, but with a flat intermediate section on a
portion of that upper cam surface. Third, the present
invention utilizes a cylinder member which has first,
second and third enlarged diameter cylindrical port
lions on the exterior of the cylinder member, the
first portion being disposed near the rear, the second
portion being disposed near the middle, and the third
portion being disposed near the front of the cylinder
member. The cylinder member also has a longitudinal
rib extending between the first and second cylindrical
portions, with the longitudinal rib having a rear sea-
lion ox substantially increased width. The cylinder's
bottom hole for receiving a projecting portion of the
tool's cylinder stop assembly is disposed in the
HMH-77
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longitudinal rib, and the cylinder's groove for
receiving the cam of the cartridge advance mechanism
is disposed in the rear rib section of substantially
increased width. The cylinder member also has a
plurality of vent holes in its second cylindrical port
lion for venting gases from the interior of the
cylinder member to the exterior of the cylinder
member. These vent holes extend at an acute angle
relative to the longitudinal axis of the cylinder and
communicate with grooves in the exterior surface of
the second cylindrical portion. The third cylindrical
portion has a pair of slots for conducting the gases
towards the tool's barrel member, and the latter is
shaped to allow gases to exit the tool. Fourthly, the
present invention utilizes a hand guard which replaces
the conventional long bottom slot normally found in
hand guards with a short slot and a groove formed con-
tenuous with that slot, so as to limit premature
exiting of gases from the tool. In addition, the hand
guard has a plural of circumferential flats
disposed on the exterior surface of the cylindrical
portion of the hand guard in order to minimize
binding between the hand guard and the tool housing on
account of the buildup of spent powder residue in that
region of the tool.
Brief Description Of The Drawings
Still other objects and features of the present
HMH-77
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3~3~
invention will be more fully disclosed or rendered
obvious in the following detailed description of the
preferred embodiment of the invention, which is to be
considered together with the accompanying drawings
wherein like numbers refer to like parts and further
wherein:
Fig. 1 is a longitudinal sectional view, with
certain portions shown in side elevation and certain
portions shown broken away, of a powder-actuated
fastener-driving tool which comprises the preferred
embodiment of the present invention;
Fig. 2 is an exploded perspective sectional view
of portions of the tool's housing assembly and
cartridge advance mechanism;
Fig. PA is a sectional view, with portions broken
away, taken-along line AYE of Fig. 2;
Fig. 2B is a sectional view taken along line
2B-2B of Fig. 20
Fig. 3 is a perspective view of the tool's barrel
member;
Fig. 4 is a perspective view of the tool's
cylinder member;
Fig. PA is a longitudinal sectional view of the
cylinder member;
Fig 5 is a perspective view of the same cylinder
member taken from a different angle of view;
Fig. 6 is a perspective view, with portions brow
ken away, of the tool's hand guard;
~MH-77
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Fig. 7 is a perspective View of the tool's
striker assembly;
Fig. 8 is a perspective view, with portions brow
ken away, of the trolls cylinder stop assembly;
Fig. 9 is an exploded perspective view, with port
lions broken away, of the trolls breech block
assembly;
Fig. 10 is an exploded perspective view, par-
tidally in section, of the tool's firing mechanism;
Fig. 11 is a front view ox a cartridge-supporting
strip used in conjunction with the tool;
Fig. 12 is a side elevation showing a plurality
of cartridges disposed in the same strip;
Fig. 13 is a cross-sectional view taken along
line 13-13 of Fig. 1 showing portions of the tool's
housing assembly, breech block assembly, cartridge
advance mechanism, and trigger assembly;
Fig. 14 is an exploded perspective view of a
fastener assembly used in conjunction with the tool;
Figs. AYE and lob are longitudinal sectional
views with certain portions shown in side elevation
and certain portions shown broken away of a pole
assembly adapted for use with the tool;
Fig. 16 is a plan view of the trigger actuator
portion of the pole assembly; and
Fig. 17 is an exploded view of the handle and cam
portions of the pole assembly.
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Detailed Desert lion Of The Preferred Embodiment
P._.
Looking first at Fig. 1, there is shown a powder-
actuated fastener-driving tool which is a preferred
embodiment of the present invention The fastener-
driving tool generally comprises a housing assembly
made up in part by a housing 100 and a rear cap 141,
barrel and cylinder assembly 200, a striker assembly
300, a cylinder stop assembly 400, a breech block
assembly 500, a firing mechanism 600, a trigger
assembly 700, and a cartridge advance mechanism 800.
Looking now at Figs. 1, 2, PA and 2B, housing 100
has a front bore 104, a front Canterbury 106 which
communicates with front bore 104 and forms a shoulder
108 at the junction thereof, a rear bore 110, a rear
Canterbury 112 which communicates with rear bore 110,
a hollow handle section 113, and an irregular
transversely-extending chamber 116 which extends from
the top side ox the tool to the bottom end of handle
section 113, and intersects and communicates with
front bore 104. Handle section 113 has an elongate
opening 111 at its rear side which communicates with
chamber 116, and housing 100 has a notched opening 117
on its underside which is an extension of opening 111.
A tranversely-extending wall 118 separates rear bore
110 from the upper portion of chamber 116. Wall 118
has openings 120, 121, 122 and 123 which extend bet-
wren rear bore 110 and chamber 116. Housing 100 also
is formed with a longitudinal channel or slot 124 in
HMH-77
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the floor of front bore 104, a pair of parallel Yen-
tidal channels 125 (see also Fig. 13) disposed in the
inner sides of the opposite side walls of handle sea-
lion 113, a first threaded bore 126 intersecting front
bore 104, and second, third and fourth bores 128, 130
and 134 intersecting front Canterbury 106. Bores 130
and 134 are threaded, while bore 128 is unthreaded.
Bores 126, 128~ 130 and 134 extend at right angles to
front bore 104 and front Canterbury 106. Bores 126,
1~8 and 130 all intersect an elliptical recess 132
formed in the bottom side of housing 100. Vertical
bore 134 has a Canterbury 136. Another threaded bore
137 intersects rear Canterbury 112 at a right angle.
Bore 137 has a Canterbury 138 (Fig. 1). Still
another threaded bore 139 in the bottom end of handle
section 113 intersects irregular chamber 116. Bore
139 has a tapered Canterbury 140 (Fig. 2) A
threaded bore 175 (Fig. 2B) passes through housing 100
and intersects front bore 104.
Referring to Fig. 1, attached to housing 100 is a
rear cap 141 and a resilient hand grip 142. Rear cap
141 is secured to the rear end of housing 100 so as to
close off bore 110. Cap 141 is bayonet mounted to
housing 100. More specifically, the latter has in
Canterbury 112 a plurality of mutually spaced raised
segments or lands 115 (Fig. 2) that cocci with similar
spaced segments 154 (Fig. 10) on the inner end of cap
141 so that the cap and housing may be locked together
Ho 77
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pa of ~,~,,
or unlocked by simply rotating the cap relative to the
housing. The cap's interior cylindrical surface 143
mates with rear bore 110 to form a single cylindrical
chamber closed off at one end by the end wall of cap
141 and at the other end by housing wall 118. Cap 141
is releasable locked in place by a set screw 144 which
is screwed into threaded bore 137 and projects into a
locking hole 119 in cap 141.
Hand grip cushion 142 cooperates with the handle
section 113 of housing 100 to form a contoured handle
or grip which may be comfortably gripped by a tool
operator. Cushion 142 has a tongue 150 at its upper
end which overlaps a lip 147 on the underside of the
housing. Cushion 142 closes off openings 117 and 111.
Cushion 142 has a center rib section 151 which extends
into opening 111 and engages two ribs 152 disposed on
the opposite side of handle section 113~ thereby pro-
venting relative Saudis movement of the cushion.
The latter is secured in place by a screw 146 which is
screwed into hole 139 and also into a threaded hole
145 in the bottom end of the cushion
Barrel and cylinder assembly Z00 is shown in
detail in Figs. 1 and 3-6. Barrel and cylinder
assembly 200 generally comprises a barrel member 202
(Fig. 3), a cylinder member 204 (Figs. 4, pa and 5), a
shock collar 206 (Fig. 1), and a hand guard 208 (Fig.
6).
Looking now at Figs. 1 and 3, barrel member 202
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has a coaxial bore 210 of circular cross-section
running for its full length The rear end of bore 210
has a frusto-conical Canterbury 212. The exterior of
barrel member 202 includes a first cylindrical region
214 provided with a pair of diametrically-opposed
bayonet flanges or lands 216, a second cylindrical
larger diameter region 218, and a third region 219
which has a smaller diameter than the first region and
has six like flats 226 which provide a hexagonal
cross-sectional configuration. The second region 218
is provided with a first pair of diametrically-opposed
longitudinally-extending grooves 220, a second pair ox
diametrically-opposed longitudinally-extending grooves
222, and a pair of diametrically-opposed
circumferentially-extending grooves 224 which inter-
sect grooves 220 and 222. It is noted that only one
each of grooves 220, 222 and 224 is visible in Fig. 3.
It is to be noted also that grooves 220 extend beyond
the opposite ends of cylindrical region 218 into first
cylindrical region 21~ and third hexagonal region 219.
Looking now at Figs. 1, 4, pa and I cylinder
member 204 has a small diameter tubular extension 228
at its rear end and its generally cylindrical exterior
surface is relieved at two areas 229 and 230 so as to
form three spaced lands 231, 232 and 233. Cylinder
member 204 has a coaxial bore 23~ that has a first
small diameter section 235 commencing at the end of
tL2bular extension 228, a second slightly smaller
HMH-77
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diameter section 23~ for the remainder of tubular sea-
lion 228, a frusto-conical transition section 237, a
relatively large diameter section 238 extending over
a major portion of its length, two still larger
diameter sections AYE and 239, a frusto-conical
shoulder go, and a front Canterbury Sal. Exterior
surface recess 229 extends trough less than
the full circumference of cylinder member 204,
resulting in a longitudinal rib 242 that extends bet-
wren lands 231 and 232 and has a rear section 244 of
substantially increased width. Cylinder member 204
also has an elongated through hole 246 along rib 242
which intersects coaxial bore 234. jib 242 also has a
pair of narrow, mutually aligned grooves 247 and 248.
Another wider groove 249 extends along rib 242
and land 231. Cylinder member 204 also includes a
plurality of round vent holes 250 which extend
radially and intersect center bore 234. Holes 250
extend at an inclined angle to the center axis of the
cylinder member, as seen best in Fig. PA. The center
land 232 has a plurality of longitudinally extending
slots or grooves 252 which intersect holes 250 at one
end and terminate at the relieved sections 230.
Still referring to Figs. 4, PA and 5, the front
land 233 has two diametrically opposed slots 256.
Additionally, Canterbury 241 is relieved at two areas
in line with slots 256 as shown at 258, and bore sea-
lion 239 is recessed at two diametrically opposed
HMH-77
I 2
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locations displaced 90' from recesses 258, as shown at
261. The small diameter tubular extension 228 serves
as a cartridge support and for this purpose its end is
slotted so as to form a plurality of fingers 254.
Looking now at Fig. 1, a resilient shock collar
206 is disposed in cylinder member 204. Collar 206 is
cylindrical in cross-section and has a peripheral rib
260. The outer diameter of rib 260 is sized so that
the rib makes a snug fit in bore section 239 of the
cylinder member.
Looking now at Figs. 1 and 6, hand guard 208
comprises a cylinder portion 262 having a plurality of
longitudinal flats 272 disposed on the outer surface
thereof, and an end portion 263 having a frost-
conically shaped outer surface. The interior surface
of the hand guard is stepped along its length so as to
define a pair of shoulders 264 and 265 fig. 1). A
pair of pins 266 are welded to the interior surface of
the hand guard 208 (or cast as an integral part
thereof) at diametrically-opposed points. The
cylinder portion 262 is slotted axially for a short
distance from its rear end as shown at 267, and it
also has a shallow axial groove 268 in its outer sun-
face aligned with and extending from slot 2670
Striker assembly 300 is shown in detail in Figs.
1 and 7. It comprises a striker member 302 formed
with a head section 304 and a shaft section 306 having
an enlarged head-connecting portion 307. A pair of
HMH-77
.
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metal keeper rings 308 are disposed in a pair of
peripheral grooves 310 formed in head section 304. As
seen in Fig. 7, head section 304 also includes a blind
axially extending hole 312 at its rear end which lung-
lions as a combustion chamber. Striker assembly 300
is slid ably disposed within cylinder member 204 in the
manner shown in Fig. 1 so that its head section 304
resides in bore section 238 ox cylinder member 204.
Keeper rings 308 form a tight sliding fit with the
interior surface of cylinder member 204. Shaft sea-
lion 306 extends through shock collar 206. Shaft sea-
lion 306 is undersized with respect to the internal
diameter of shock collar 206. However, the connecting
portion 307 of the striker is sized so as to make a
close sliding fit with the shock collar. Shaft sea-
lion 306 of the striker is long enough for it to make
a close sliding fit in bore 210 of barrel member 202.
Barrel member 202, cylinder member 204, shock
collar 206, and hand guard 208 are all adapted to be
quickly and easily assembled together so as to collect
lively form the complete barrel and cylinder assembly
200 in association with the striker assembly 300, in
the manner shown in Fig. 1. The first step is to
insert striker member 302 in cylinder member 204 so
that its head section 304 is located in bore section
238. Next shock collar 206 is inserted into cylinder
member 204 with its peripheral rib 260 contacting the
surface defining bore section ~39 of cylinder member
HMH-77
.. . , .. . _ . . . ... ... . .. . . . . . ...
~2~3~
-16-
204. Next barrel member 202 is inserted into cylinder
member 204 so that shock collar 206 protrudes into the
frusto-conical Canterbury 212 of the barrel member.
In inserting the barrel flanges 216 are first aligned
with recesses 258, thereby allowing flanges 216 to be
moved axially into contact with the shoulder 273
formed by bore section 239 and Canterbury 241. Then
the barrel is rotated 90 , thereby allowing the barrel
to be moved into the cylinder member far enough or
flanges 216 to fit in recesses 261 against shoulder
240. At this point the barrel member is locked
against rotation relative to the cylinder but is free
to move axially away from the cylinder member. At
this point the barrel and cylinder member can be
detached by moving them away from one another until
flanges 216-reside in Canterbury 241, at which point
the barrel member can be rotated 90~ to place flanges
216 in alignment with recesses 258, thereby allowing
the barrel to be pulled clear of the cylinder. After
barrel member 202 has been installed in cylinder
member 204, barrel member 202 is coupled to hand guard
20~ by a bayonet mounting arrangement hereinafter
described.
To this end, a compression spring 269 (Fig. 1) is
first loaded into hand guard 208 until it is entrapped
between shoulder 265 and pins 266 at the front end ox
the hand guard. Then barrel member 202 is inserted,
hexagonal end first, into hand guard 208 so that the
HMH-77
I
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forward end of the barrel member's second cylindrical
region 218 is stopped by pins 266. Then the cylinder
is rotated so as to align barrel member grooves 220
with hand guard pins 266. Then by forcing the
cylinder and hand guard toward one another, the barrel
is pushed further into the hand guard against the
pressure of spring 269 far enough to align pins 266
with grooves 224, at which point the hand guard is
rotated to move pins 266 into grooves 222. Then the
hand guard and barrel member are released, thereby
allowing spring 269 to force the cylinder and barrel
assembly to telescope to the extent permitted by rota-
live movement of pins 266 in grooves 222, with the
result that the barrel will be locked to the hand
guard by virtue of pins 266 residing in grooves 222 -
and spring 269 urging the barrel member and hand guard
axially away from one another. At this point the
cylinder member 204 and the associated striker
assembly may be withdrawn and separated from the
locked hand guard and barrel member by pa) pulling the
cylinder member axially away from the hand guard far
enough to cause flanges 216 to be aligned with count
terbore 241, (b) rotating the cylinder turn so that
flanges 216 are aligned with recesses 258, and then
(c) pulling the cylinder member and hand guard apart.
When barrel and cylinder assembly 200 is
assembled as above described, barrel member 202 is
locked against rotation relative to hand guard 208,
HMH-77
-18-
hand guard 20~ and barrel member 202 are capable of
telescoping movement toward one another in opposition
to the bias of spring 269, and the hexagonal end of
barrel member 202 extends out through the frost-
conical shaped front end of hand guard 208~
Barrel and cylinder assembly 200 and striker
assembly 300 are received by housing 100 in the manner
shown in Fig. 1. More specifically, and referring
also to Fig. 2, barrel and cylinder assembly 200
(including striker assembly 300) is positioned within
the housing so that the recessed cylindrical portion
229 of cylinder member 204 is slid ably disposed par-
tidally in bore 104 and partially in Canterbury 106
and the cylindrical portion 262 of hand guard 208 is
slid ably disposed in Canterbury 106, with the front
end portion of hand guard 208 and hexagonal section
219 ox barrel member 202 extending out from the front
end of housing 100. The outer diameter of cylindrical
portion 262 is such that the hand guard makes a close
sliding Kit in Canterbury 106 of the housing, with
the flats 272 serving to define a plurality of
passageways between the hand guard and adjacent inner
surface of the housing for allowing gases to pass out
from behind the hand guard. In installing the barrel
and cylinder assembly 200 in housing 100, care is
taken to make certain that (a) slot 267 of hand guard
20~, grooves 220 of barrel member 202, and the
elongated opening 2~6 and aligned slots 256 ox
HMH-77
issue
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cylinder member 204 are aligned with the housing's
vertical bores 126, 128, 130 and 134, (b) groove 249
of cylinder member 204 is aligned with channel 124 of
the housing, and (c) grooves 247 and 248 of cylinder
member 204 are aligned with the housing's threaded
bore 175 (Fig. 2B).
Installation of the barrel and cylinder assembly
200 in the housing requires manipulation of the
cylinder stop assembly 400 (Figs. 1 and 8), which
serves to limit the extent to which the barrel and
cylinder assembly can reciprocate in housing 100.
Looking now at Figs. 1 and 8, cylinder stop
assembly 400 generally comprises a cylindrical
housing 402 having an elliptical flange 403 which fits
into elliptical opening 132 of housing 100, a cylinder
stop pin 404 slid ably disposed in housing 402 and
having an enlarged knob 406 on its outer end, and a
compression spring 408. Cylinder stop pin 404 is
shaped so as to have a top angulated fin 410~ a pair
of angulated shoulders 411 on opposite sides of fin
410, and a flange 4120 Spring 408 is captivated bet-
wren flange 412 and knob 406. The spring biases the
stop pin so that fin 410 will protrude from the top
end of housing 402.
Cylinder stop housing 402 is mounted in bore 128
of housing 100 with its elliptical flange 403 received
by elliptical recess 132. The cylinder stop assembly
400 is secured in place by screws 416 and 418 which
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I
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are screwed into threaded bores 126 and 130 respect
lively. When so installed, fin 410 of cylinder stop
pin 40~ extends up into Canterbury 106 of the housing
far enough to block insertion of cylinder member 20g
into bore 104. Accordingly, installation of barrel and
cylinder assembly 200 into the housing requires that
the elongated aperture 246 of the cylinder member and
the slot 267 of the hand guard be aligned with stop
pin 404, and that the stop pin be pulled out enough to
permit the cylinder member to be inserted far enough
to locate the rear end of its aperture 246 beyond the
stop pin 404~ The fin 410 is narrow enough to fit
into the cylinder member's aperture 246, but the fin's
shoulders 411 are just wide enough not to fit in
the aperture 246t though not so wide as to prevent
them from fitting in the hand guard's slot 267r
Accordingly, when fin 410 is held in it extended
position by spring 40~ the travel ox barrel and
cylinder assembly 200 relative to housing 100 is
limited by the length of aperture 246 in cylinder
member 204. If cylinder stop knob 406 is pulled out
with sufficient force to overcome spring 40~, top fin
410 can be entirely withdrawn from the aperture 246 of
cylinder member 204, thereby freeing the barrel and
cylinder assembly 200 so that it can be removed by
pulling it out of the front end of housing 100.
It is to be appreciated that the interaction of
fin 410 of cylinder stop assembly 400 with the
~MH-77
, 9
I
elongated opening 246 of cylinder member 204 limits
both the longitudinal and the rotational travel of the
barrel and cylinder assembly 200 relative to housing
100. The same interaction also assures alignment of
the cylinder member's groove 249 with the housing's
horizontal channel 124, alignment of the cylinder
members grooves 247 and 248 with housing bore 175,
and alignment of groove 268 of the hand guard with a
screw 420 which is received by threaded hole 134 and
is just long enough to extend into groove 268. This
co-action of groove 268 and screw 420 assures that
hand guard 208 will always have its slot 267 aligned
with and ready to receive top fin 410 of cylinder stop
assembly 400.
A Yeller 425 is disposed in threaded bore 175 of
housing fugue. 2B), in order to provide a limited
drag on the movement of barrel and cylinder assembly
200 within housing 100. This limited drag is sup-
fishnet to keep barrel and cylinder assembly 200
substantially motionless during normal handling of the
tool, e.g. during carrying about a worksheet, but the
drag is not so great as to interfere with intentional
operational movement of the barrel and cylinder
assembly with respect to the housing. Belier 425
comprises a threaded casing 428 which is screwed into
bore 175, a pin 426 slid ably mounted in a bore in the
casing, a spring 427 forcing the pin to project into
bore 104 of housing 100, and a threaded member 429
~MH-77
~2~33~;~
mounted in the casing so as to hold spring 427. The
forward end of pin 426 is normally received by one or
the other of the cylinder member's grooves 247 and
248, or bears against that part of the exterior sun-
face of the cylinder member which extends between
grooves 247 and 2480
Breech block assembly 500 is disposed in the
upper portion of chamber 116. Looking now at Figs. 1,
9 and 13, breech block assembly 500 generally compare-
sues a breech block 502 which has a generally fee-
angular horizontal cross-section, a pair of spring
cups 504, a pair of compression springs 506, a pair of
steel balls 508, a firing pin housing 510, a pair of
alignment dowel pins 512, a firing pin 514, and a
compression-type firing pin spring 516. Firing pin
housing 510 is disposed in a rear extension 153 of
chamber 116. Breech block 502 is formed with an
interior cavity or chamber 518 which extends through
it from top to bottom, as seen in Figs. 1, 9 and 13.
Breech block 502 has a pair of oppositely disposed
slots 520 which form side extensions of cavity 518.
The front side of tune breech block has an opening 519
(jigs. 9 and 13~ which is large enough to accommodate
the cartridge support extension 228 of cylinder member
204. A pair of parallel horizontal bores 522 and
matched counter bores 524 extend from one side of
breech block 502 into the block and intersect slots
520. The inner ends of holes 522 are spherically
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tapered to a diameter slightly less than that of balls
508. Balls 508 and springs 506 are positioned in
bores 522 and cups 504 are secured in counter bores 524
as shown in Figs. 9 and 13, so that the balls 508 pro-
jet partially into the slots 520 under the force of
springs 506.
Breech block 502 also includes a tapered bore 526
and a pair of parallel bores 528 which pass through
its rear side into cavity 518. Bores 528 are aligned
with a pair of bores 530 in firing pin housing 510 so
as to accommodate alignment pins 512 which extend bet-
wren both breech block 502 and firing pin housing 510
(Figs. l and 9). Firing pin housing 510 also has a
bore 532 and a Canterbury 534 which, when firing pin
housing 510 is in engagement with breech block 502l
cocci with tapered bore 526 so as to provide a chamber
for housing firing pin 514 and firing pin compression
spring 516. Firing pin 514 normally resides entirely
within the aforementioned chamber and, because of the
action of spring 516, does not project into cavity 518
in breech block 502. However, by overcoming the force
of firing pin spring 516 the firing pin can be caused
to project its pointed end into interior cavity 518.
Breech block 502 also includes a pair of threaded
holes 535 and 536 in its rear side and a bore 537
which passes all the way through the block parallel to
bores 528.
Breech block assembly 500 is secured in place in
HMH-77
-24-
chamber 116 by a pair of screws (not shown) which pass
through holes 120 and 121 in wall 118 and are screwed
into holes 535 and 536 of block 502. When breech
block assembly 500 is so secured in housing 100, the
opposed vertical slots 520 in breech block 502 are
aligned with the vertical channels 125 in housing 100
(Fig. 13), and also the axis of firing pin 514 is
aligned off-center relative to the axis of cartridge
support extension 228 of cylinder member 204. At the
same time, bore 532 and Canterbury 534 in firing pin
nosing 510 are aligned with opening 122 in wall 118
of housing 100, and bore 537 in breech block 502 is
aligned with hole 123 in housing wall 118.
Looking next at Figs. 1 and 10, wiring mechanism
600 generally comprises a firing pin actuator housing
602f three compression springs 604, 610 and 618, a
latch or key release 606, a pair of retaining pins 6~7
a firing pin actuator 608, a spring retaining sleeve
612 having an internal front flange 613 and an ester-
net rear Lange 615, a retaining ring 614, and a
washer 616~ Firing mechanism 600 is disposed in the
chamber at the rear of housing 100 between housing
wall 118 and rear cap 141. Spring retaining sleeve
612 is locked to rear cap 141 by a retaining ring 614
which is received by an interior groove in cap 141.
Spring 618 forces washer 616 away from rear cap 141
and against the flange 613 of spring retaining sleeve
612. Spring 610 surrounds against the outer surface
HMH-77
. . . . . ..
~2~3~
-25-
of spring retaining sleeve 612 and extends into an
interior groove 619 in housing 602. Spring 610 forces
firing pin housing 602 away from rear cap 141 and
against housing wall 118.
Firing pin actuator 608 is disposed so that its
rear end enters spring retaining sleeve 612 and its
shoulder 611 can engage washer 616, while its forward
end projects through a center opening 620 in actuator
housing 602, Firing pin actuator 608 is formed with a
pair of oppositely disposed recessed flat sides 621
each shaped to provide a flat ridge 622 (only one of
which is shown) which is notched in elevation as shown
at 624. Firing yin actuator 608 is designed to make a
close sliding fit through a key-shaped opening 626 in
latch 606. The latter is mounted in a transverse
opening inn housing 602 and is biased by
compression spring 604 which is seated in a depression
629 that is an extension of opening 627. Latch 606 is
held in place in opening 627 by the two retaining pins
607 which intercept shoulders 62~ of the latch. The
shoulders 605 of latch 606 are arranged to side along
the ridges 622 and notches 624. The notches are
disposed so that when engaged by shoulders 605 the
front end of the actuator will protrude slightly
beyond the front end of housing 602 as shown in Fig.
1. The underside of housing 602 also is recessed as
shown at 631 to receive the rear extension 720 of a
release lever 706r as will hereinafter be described in
HMH-77
-26-
detail. Also forming part of the firing mechanism is
an axially extending push rod 630 which is attached to
firing pin housing 602 and extends through hole 123 in
wall 118 and through bore 537 in breech block 502, as
will hereinafter also be described in detail.
The length of ridges 622 are set so as to permit
firing pin actuator 608 to be driven forward by spring
618 enough for its front tip 632 to project through
opening 620 far enough to engage and drive firing pin
514 forward, so as to fire a cartridge disposed in
cartridge holder 228. If actuator housing 602 is
forced backward toward cap 1~1 against the power of
spring 610, firing pin actuator 608 will also be
carried back against the force of spring 618, on
account of the notched portions 624 of the actuator
608 being engaged by the shoulders 605 of the latch.
If while the actuator housing 602 is compressing
spring 610 latch 606 should be forced upward into
housing 602 against the force of spring 604 so as to
disengage shoulders 605 from notches 624, the actuator
608 will be freed and spring 618 will drive it forward
with great force. Firing mechanism 600 is specific
gaily designed so that this forward movement of firing
pin actuator 608 will result in the forward end 632 of
the firing pin actuator 608 passing through the
opening 122 in housing wall 118, so as to contact and
drive firing pin 514 forward so that its tip will
intrude into the interior cavity 518 of breech block
HMH-77
I
502.
Still looking now at Figs. 1 and 10, actuator
housing 602 is adapted to be moved backward within its
chamber in housing 100 on account of its attachment to
push rod 630. This rod, which is affixed in the front
side of actuator 602, is slid ably disposed in opening
123 in housing wall 118 and through bore 537 in breech
block 502~ and extends into bore 104 so as to be able
to engage the rear wall portion 251 of cylinder member
204 (see Fig. pa). Push rod 630 is sized so that when
actuator housing 602 is held forward by spring 610 in
contact with wall 118 of housing 100, as it normally
does in the absence of any outside forces, it may be
engaged by wall portion 251 of cylinder member ?04 and
while so engaged, the fingers 254 at the end of
cartridge support extension 228 will protrude slightly
into breech block cavity 518, and the fin 410 of
cylinder stop assembly 400 will be disposed inter-
mediate the two ends of the cylinder member's bottom
aperture 246. At the same time, however, push rod 630
is sized so that if the projecting hexagonal portion
of barrel member 202 should be forced back into the
nail-driving tool with sufficient force to overcome
the action of spring 610, actuator housing 602 may be
forced backwards sufficiently far within its chamber
as to enable firing pin actuator 608 to effectively
strike firing pin 514 if latch 606 should be sub-
sequently moved to its release position, as noted
HMH-77
-
33~
-28-
above.
Firing mechanism latch 606 is designed to be
moved upward against the force of spring 604 to its
release position by trigger assembly 700. Looking now
at Figs. 1 and 13, trigger assembly 700 generally
comprises a trigger 702, a trigger push rod 704, a
release lever 706, a torsion spring 708, a dowel pin
710, and a dowel pin 712. Pins 710 and 712 have their
opposite ends anchored in the side wails of housing
100 and they extend across the bottom opening 117
(Fig. 2) which is directly behind and communicates
with cavity 116. Lever 706 is pivotal mounted on
dowel pin 710. Torsion spring 708 is mounted on dowel
pin 710 and has one end trapped by dowel pin 712 and
its other end trapped by lever 706. Spring 708 biases
lever 706 counterclockwise teas seen in Fig. 1) away
from actuator housing 602. Trigger 702 is slid ably
mounted in a rectangular opening 703 in the front wall
of handle section 113 (Fig. 2). Trigger push rod 704
has rounded ends with one end disposed in a rounded
depression in the rear extension 711 of trigger 702,
and the other end disposed in a rounded depression in
lever 706. Push rod 704 couples trigger 702 to pin
release lever 706 so that trigger 702 will normally be
biased into its extended position (Fig. 1) under the
influence of torsion spring 708. The forward or
extended position of the trigger is determined by
engagement of a portion of the trigger with a shoulder
HMH~77
I
-29-
715 of housing 100 (Fig. 2). When trigger 702 is
urged rearwardly with sufficient force to overcome
torsion spring 708, pin release lever 706 will be
pivoted upward against actuator housing 602. The
various parts are appropriately sized so that when
barrel and cylinder assembly 200 is forced rearwardly
into housing 100 to the extent permitted by the eying-
cement of the forward end of cylinder aperture 246
with stop fin 410, thereby pushing actuator housing
602 rearward in its chamber, actuator latch 606 will
reside directly above the extension 720 on pin
release lever 706, so that if the trigger is then
pulled back, the lever 706 will move up far enough for
its extension 720 to engage latch 606 and raise it to
release position so as to free actuator 608.
As seen in Figs. 1 and 13, the transverse rear
extension 711 of trigger 702 is coupled to the trigger
by two parallel spaced connecting sections 713 which
extend through the chamber 116 adjacent parallel Yen-
tidal channels 125. Trigger 702, its rear extension
711, and its connecting sections 713 form an opening
to accommodate a strip of gunpowder cartridges as will
hereinafter be described.
One such cartridge strip 802 is shown in Figs. 11
and 12. The strip is of symmetrical design, having a
plurality of uniformly spaced indexing slots 804 in
its two side edges. The strip 802 also has a plural
lily of central openings 808, each in the form of a
HMH-77
.. .. . . .. .. . .
-30-
cross, to accommodate cartridges 810 as shown. The
four slots characterizing each opening 808 are sized
to accommodate the fingers 25~ of cylinder member 204,
so that the fingers may engage the underside of the
rim of a cartridge while the tapered forward portion
of the cartridge projects into cylinder extension 228.
Cartridge advance mechanism 800 serves to advance
a strip 802 of cartridges 810 so that each cartridge
in turn is located in firing position. Cartridge
advance mechanism 800, shown in Figs. 1, 2 and 13,
generally comprises a strip feed cam 812, a dowel
pivot pin 814r a paw 815, and a spring 818. Pivot
pin 814 is secured in a hole 815 which intersects slot
124 in housing 100. Strip feed cam 812 resides in
housing channel 124 and pivots about dowel pin 81~.
Cam 812 has an upper cam surface 820 which is
generally rounded but has a flat intermediate section
821. Cam surface 820 is adapted to ride in groove 249
in cylinder member 204. The rear end of cam 812 has a
finger 822 which extends into slot 819 (Fig. 13~ in
breech block 502 in position to engage the underside
of paw 816~ When cylinder member 204 reciprocates
within housing 100, it causes cam 812 to pivot about
dowel pin 814 and thereby alternately raise and lower
its finger 822. As seen in Figs. 9 and 13, breech
block 502 has a depending fin 817, and it also has a
narrow slot 819 (Fig. 13) in one side which is con-
tinted down into the outer side of fin 817~ Slot 819
HMH-77
I
communicates through a vertically elongate opening
with one of the cartridge strip guide grooves 520.
Paw 816 resides in slot 819. The upper end of paw
816 has a pointed finger 824 which extends through tune
vertically elongate opening into groove 520 when it is
in its upper position, i.e., the position shown in
Fig. 13. The upper end of spring 818 resides in a
depression in breech block 502 while its bottom end
engages an inclined upper edge of paw 816. Spring
818 urges the paw (and earn finger 822) downward.
When the cylinder is extended, cam finger 822 will be
lower than the position shown in Figs. 1 and 13 and so
will paw 816. Cam finger 822 engages the paw adja-
cent to its lower left corner. Hence as finger 822 is
raised, it applies a rotational force to the paw
which urges its finger 824 into groove 520. Hence as
the pointed paw finger 824 passes up beyond the lower
border of the aperture connecting slot 819 with groove
520, the paw finger will enter one of the notches in
the cartridge strip ~02 disposed in grooves 520 and
cause the strip to be indexed upward with it. When
cam finger 822 is no longer forced upwardly, spring
818 will cause the paw to move down and also cause
the cam finger 822 to move with it. As the paw moves
down, the slanted underside of its finger 824 will
cause the paw to move past the strip which will be
held by detent balls 508. The spring 818 will also
cause the paw to rotate its finger away from the
HMH-77
33~
strip so as to permit the paw to more easily move
down in slot 819.
It is to be noted that a cartridge strip 802
bearing cartridges 810 may be inserted into the open
bottom end of the tool handle into the opposing
parallel channels 125 and pushed upward through the
aforementioned opening former by trigger parts ill and
713 Figs. 1 and 13) into the grooves 520 of breech
block 502, until one of the indexing slots ~04 is
engaged by finger 824 of paw 816. Thereafter, each
time cylinder member 204 is reciprocated forward and
backward within housing 100~ cam 812 will pivot to
respectively lower and raise its finger 822, which in
turn will cause the finger 824 of paw 816 to move
down and up respectively. On account of the slanted
underside of finger 824, and the engagement of steel
balls 5C~ of breech block assembly 500 with indexing
slots 804 in the opposite edge of strip 802, each come
brined forward and then backward reciprocation of
cylinder member 204 will cause the cartridge strip 802
to advance one step. The various members are
appropriately sized so that each advancement brings a
new cartridge into alignment with cartridge support
projection 228 of the cylinder member 204. In this
position, the axis of each cartridge ~10 resides
slightly below the tip ox firing pin 514 so as to
enable the cartridge to be rim-fired.
Operation of the fastener-driving tool will now
HMH-77
.
I
-33-
be described.
Starting with the tool in its "at rest" position,
i.e. where the tool is in the state shown in Fig. 1,
the tool is readied for use by inserting a cartridge
strip 802 into the nail gun as previously described,
so that a cartridge 810 resides inside breech block
502 aligned with and immediately behind cartridge sup-
port projection 228. Then a nail assembly 900,
comprising a nail 902 engaged in a resilient finned
nail support 904, as shown in Fig 14, is inserted
into the front end of central bore 210 of barrel
member 202. Nail support 904 serves to keep the shaft
of nail 902 aligned in the bore 210 of barrel member
202, and also provides sufficient friction with the
surrounding wells of the barrel member 202 to hold
nail 902 in-place as the nail-driving tool is moved
about. At this point the tool is in its "ready"
position.
However, if at this point a tool operator were to
pull the trigger of the tool, without taking any
further action, nothing would happen. This is because
at this stage actuator housing 602 is held by spring
610 in its forward position engaging wall 118 of
housing 100, with the result that pin release lever
706 is blocked by the underside of the actuator
housing so as to be incapable of activating firing
mechanism 600 to drive firing pin 514 forward to con-
tact a cartridge 810.
HMH-77
I
-34-
Similarly, if at this point a tool operator
were to grasp hand guard 208 and pull it backwards
towards breech block assembly 500 and then pull the
trigger, again actuator housing 602 would remain in
its forward position and again nothing would happen.
This is because as hand guard 208 is pulled backwards,
it would move the cylinder back with it until the
spring force of springs 610 and 618 exceeds the force
of spring 269, whereupon backward movement of the
cylinder would stop and the hand guard would simply
slide backwards against the pressure of spring 269
until the end of the hand guard is stopped by engage-
mint with shoulder 108 of housing 100. The spring
force of springs 610 and 618 is sufficient to stop the
backward movement of the cylinder member within the
housing before the latch 606 is aligned with extension
7~0 of trigger lever 706. As a result, trigger 702
cannot cause firing mechanism 500 to drive firing pin
514 forward to contact a cartridge 810.
However, if while the tool is in its "ready"
position, i.e., with the cylinder in the position
shown in Fig. it the front end of barrel member 202
should be placed against a workups and the tool
pressed forward to place it in its "fire" position,
and the trigger 702 then depressed, the tool will
fire. This is because forcing the tool against a
workups to put it into its "fire" position will
cause the barrel and cylinder assembly 200 to slide
HMH-77
I
-35-
rearward inside the tool far enough for cylinder
member 204 to chamber the cartridge S10 in its
cartridge support extension 228 and at the same time,
on account of push rod 630, actuator housing 602 will
be forced into its rearward firing position where its
latch 606 will be aligned with the projection 720 of
lever 706. During this operation striker member 302
is carried backwards with cylinder member 204 on
account of the tight engagement its keeper rings 308
make with the interior surfaces of the cylinder
member. If now trigger 702 is pulled, it will cause
pin release lever 706 to move upward, in triune forcing
latch 606 upwards and thereby freeing firing pin
actuator 608 so that it will move forward under the
action of spring 618 and thereby drive firing pin 514
into rim contact with cartridge 810. This causes the
chambered cartridge 810 to fire. The resulting hot
gases of combustion flow into the interior of cylinder
member extension 228 and into the combustion chamber
312 of striker member 302, thus driving striker member
302 forward within barrel and cylinder assembly 200
into contact with nail assembly 900 so as to propel
the nail assembly 900 out of barrel member 202 and
into the workups. As this occurs, substantially all
of the hot gases of combustion behind striker member
302 pass along the interior of cylinder member 20~
until they reach vent holes 250. The gases flow out
vent holes 250, along grooves 252 formed in the
H~-77
`~--
I
cylinder member's cylindrical portion 232 and then
expand into the region defined between the exterior
section 230 of cylinder member 204 and the interior of
hand guard 208. From there, the gases pass along
grooves 256 in cylinder member 204 and enter grooves
220 in barrel member 202~ Then the gases exit the
tool through the spaces formed between the hexagonally
disposed outer surfaces 226 of barrel member 202 and
the circular interior surfaces of hand guard 208. It
is to be appreciated that, by keeping slot 267 of hand
guard 208 as short as possible, very little, if any,
gas will be able to exit the tool via that slot. For
this reason, slot 267 has a length such that it does
not extend beyond the screw 420 when the tool is
fired. As a result, the tool utilizes the explosive
power of a cartridge 810 with great efficiency to
drive the striker member.
The forward motion of striker member 302 should
normally stop when its front end engages the
workups; however, if the workups should fail to
stop the forward motion of the striker (e.g., in the
case where the workups is formed of soft wood), the
engagement of the striker's head section 30~ with
shock collar 206 will stop the forward motion of
striker member 302. In either case, the forward move-
mint of striker member 302 is stopped before its head
section 304 can engage top fin 410 of cylinder stop in
40~.
HMH-77
- -
I
-37-
The tool is then readied for another firing as
follows. First, the tool it lifted away from its
engagement with the workups, and then barrel and
cylinder assembly 200 is disengaged from its contact
with spent cartridge 810 and brought forward to the
limit of aperture 246, either by pulling forward on hand
guard 208 or by "throwing" the tool in a forward
motion with a snap of the wrist. This action causes
striker member 302 to return its head portion 304 into
engagement with the rear portion of cylinder member
204, since cylinder member 204 will be moving forward
within housing 100 and striker member 302 will be
blocked from further forward movement by engagement of
its head portion with fin 410 of cylinder stop
assembly 400, so that the two parts once more occupy-
the position shown in Fig. 1 relative to one another.
At the same time, the movement of cylinder member 204
in a forward direction within nosing 100 Jill allow
cam member 812 to pivot about dowel 814, thereby
allowing spring 818 to cause paw 816 to drop downward
in slot 819 to engage another notch 804 of cartridge
strip 802. Then barrel and cylinder assembly 200 is
brought back to the position shown in Fig 1 by
pushing rearward on hand guard 208. As barrel and
cylinder assembly 200 is returned, striker member 302
moves back with it on account of the tight engagement
of keeper rings 308 with the interior of cylinder
member 204. The return movement of barrel and
H~H-77
I
-38-
cylinder assembly 200 causes cylinder member 204 to
engage push rod 630 once more. At the same time, this
return movement of barrel and cylinder assembly 200
causes cam member 812 to pivot once more on dowel 814,
thereby driving paw 816 upward and thus indexing
cartridge strip 802 upward so that the spent cartridge
is moved away, and a fresh cartridge is brought into
position adjacent the firing pin.
t this point the fastener-driving tool has been
returned to its "ready" position, as previously
described. Subsequent firings are achieved by
repeating the operation set forth above.
Advantages Of The Invention
The powder-activated fastener-driving tool
described above offers a number of advantages over the
prior art.
First, the disclosed powder-actuated fastener-
driving tool is mechanically simpler than many of the
magazine type prior art tools, so that it is cheaper to
manufacture, easier to assemble, and more reliable in
operation.
Second, the disclosed tool is equipped with
improved exhaust passages for venting the hot gases of
combustion from the interior of the tool, so that the
tool is quieter has less recoil, is more energy effi-
client Rand hence more powerful), and has less tendency
to jam on account of the buildup of spent powder nest-
HOWE
~2~3~2
-39-
due within the interior of the tool.
Third, the disclosed tool is capable of using a
so-called "Red" charge cartridge with a light weight
fastener and still be considered a "low velocity"
tool.
Fourth, the tool can be easily disassembled in
the field, in order to facilitate maintenance. In
this respect it is noted that the entire barrel and
cylinder assembly 200 can be withdrawn from the
housing s ply by pulling on stop knob 406 of cylinder
stop assembly 400, and the entire trigger assembly 700
can be exposed simply by removing screw 1~6 at the
bottom of handle section 113 and pulling off hand grip
142. Removal of trigger 702 is easily accomplished by
pulling the trigger push rod out from between the
trigger and release lever 706, and then sliding the
trigger rearwardly out of the handle section: In
addition, firing mechanism 600 can be withdrawn from
housing 100 simply by unscrewing screw 144 from the
rear of the housing and removing rear cap 141 from its
bayonet connection to the housing.
Fifth, the disclosed tool can be adapted to drive
fasteners of differing types and dimensions (e.g.,
nails, eye-pins, threaded pins, etc.) simply by
removing the barrel and striker and substituting a
different barrel and striker having different dime-
sons.
.. ..
- -
I
-40-
Sixth, the disclosed tool is easily adapted for
use in conjunction with a pole assembly of superior
design so as to form a superior pole tool, as evil
dented in the following section entitled "modification
Of The Invention.
Seventh, the disclosed tool utilizes an improved
trigger assembly which is simple, relatively cheap to
manufacture, and does not cause the tool to jam. In
some prior art tools it is difficult to remove a
cartridge strip which has become jammed as a result of
its being improperly made or improperly installed in
the tool or the tool being used improperly. The
improved trigger assembly helps to reduce such jamming
and also facilitates removal of a strip which may have
become jammed.
And eighth, the disclosed tool utilizes an
improved cam arrangement in its cartridge advance
mechanism, in the form of a flattened region on the
top of the cam to minimize cam wear and reduce main-
tenancy and tool jamming. Additionally the groove 249
of the cylinder member assures that cam 812 will make
proper contact with the cylinder member and assist in
preventing rotation of the cylinder in housing 100.
It is to be noted also that cap 141 is locked to
sleeve 612 so that those members plus spring 618 and
washer 616 form a discrete subassembly. Hence when
cap 141 is removed from housing 100, sleeve 612,
spring 618 and washer 616 are removed with it.
HMH-77
2~3~
-41-
Modification Of The Invention
.
As previously described, the powder-actuated
nail-driving tool is adapted to be utilized by a tool
operation who grasps the tool about the handle portion
of the housing with one hand and then activates
trigger member 702 with the index finger of that hand.
It is foreseen, however, that it may be desired to use
the tool to drive nails into certain hard-to-reach
places e.g. ceilings in which case the tool is
modified to accommodate a pole assembly 950 having a
remote trigger operating mechanism as shown in Figs.
15-17.
Looking now at Figs. AYE and 15B the modified
tool shown in phantom at A is identical to the powder-
actuated nail-driving tool previously describer
except that-the original tool's rear cap 141 has been
replaced by a new rear cap aye adapted to facilitate
attachment of pole assembly 950. Cap aye is the same
as cap 141 except it has a hollow cylindrical extent
soon of collar 952 at its rear end sized to receive
therein one end of the pole member 954 which is part
of pole assembly 950. Pole member 954 is fixed to
cylindrical extension 952 by a pin 956, whereby the
nailing tool is firmly attached to the end of pole
member 954.
Pole member 954 is hollow in order that it may
slid ably accommodate a force transmitting assembly 960
therein Pole member 954 includes a side opening 962
HMH-77
----
~2~3~
I
adjacent extension 952 to allow a portion ox force-
transmitting assembly 960 to extend outside of the
pole and be connected to trigger 702. Force-
transmitting assembly 960 comprises a solid rod 966
having a yoke 968 attached to its forward end. Yoke
968 is slid ably disposed within a guide collar 969
secured within the pole. The forked end ox yoke 968
is pivotal secured to a right and left hand screw
coupling consisting ox a first coupling member 970
which has a tapped hole into which is screwed the
threaded end of a second coupling member 972. The
latter in turn has a tapped hole in which is screwed
the threaded end of a trigger actuating member 974.
The threaded connection between coupling members 970
and 972 is right-handed while that between coupling
member 972 and actuating member 974 is left-handed.
us a consequence, rotating coupling member 972 in one
direction will bring the actuator closer to coupling
member 970 while rotating it in the opposite direction
will move them further apart. A lock nut 976 on
coupling member 972 is used to lock the two coupling
members together. Actuator member 974 has a hooked
end 97~ and is shaped so as to go around one side of
handle section 113 of the tool so that its hooked end
will be hooked around the front edge of trigger 702D
By selectively adjusting the screw coupling the
trigger actuating member 974 can be made to snugly
wrap around trigger member 702, thereby assuring that
MY 77
I
if force transmitting rod 966 is moved axially within
pole member 954 away from end cap aye, trigger member
702 will be pulled back to firing position by trigger
actuating member 974.
Turning now to Figs. 15B and 17, the force
transmitting assembly is adapted to be moved towards
and away from end cap aye by a cam arrangement. More
particularly, rod 966 is screwed into a plastic icily-
ion pull rod 980 which is pivotal connected by a
pivot pin 982 to the forked end of a cam follower 9830
Insulator pull rod 980 has an elongated hole 984 which
receives a guide pin 985 that extends cross-wise in
pole 954 and is secured to handle stop collar 998.
Pin 985 locks the stop collar to the pole.
Cam follower 983 comprises a reduced diameter
cylindrical section 986 having a diametrically
extending bore 987 (Fig. 17) which accommodates a cam
follower pin 988 (Fig. 15B). The reduced diameter
section 986 of the cam follower makes a close sliding
fit in a hollow portion of a cylindrical cam 989
disposed within pole 954. The hollow portion ox cam
989 has two diametrically opposed helically contoured
holes 990 in its side wall to accommodate opposite end
portions of pin 988. The length of pin 988 is the
same ox slightly less than the outside diameter of cam
989. Preferably pin 988 is free to slide axially in
bore 987 and its ends are rounded so as to facilitate
movement relative to the inner surface ox the pole.
HMU1-77
I
Cam 9~9 is secured to a cylindrical handle 991 which
rotatable surrounds pole 954 by means of a pin 992.
The latter extends through a hole 993 in pole 954
which is elongated circumferential through an angle
of about 90 degrees so as to permit the handle to be
rotated a quarter turn relative to the pole. Cam 989
has a reduced diameter section 994 which is surrounded
by a torsion spring 995. One end of spring 995 is
anchored in a slot in cam 989 while its other end is
trapped in a hole 996 in the side wall of pole 954.
Spring 995 biases the cam so that cam pin 988
normally resides in the ends of holes 990 which are
nearest to cam follower 983, so that a gap 999 exists
between them as shown in Fig. 15B~ The left and right
hand coupling is set so that when gap 999 exists, the
actuating member will lie close to but will not exert
an pressure on trigger member 702. However, if
handle 991 is turned relative to pole 95~, pin 988
coats with holes 990 so as to reduce gap 999 and the
force-transmitting assembly 9~0 will move away from
rear cap aye and thereby cause trigger member 70~ to
be depressed. Thus, if a cartridge is disposed in the
breech block in firing position and handle 991 is
rotated approximately a quarter turn while the barrel
of the tool is pressed against a ceiling, the handle
rotation will cause the tool to fire the cartridge and
thereby drive a nail in the ceiling.
It will, of course, be appreciated that pole
HMH-77
~2~3~
-45-
assembly 950 may be fabricated in varying lengths
depending on the job at hand. In any event, firing
the tool by rotating the handle is advantageous in
that the operator can grasp the handle as well as the
pole to press the tool against an overhead workups.
Also the rotational mode of operation reduces the risk
of accidental firing of to tool. In addition, the
pole assembly lacks protruding external parts which
can cause accidents. Prior pole assemblies commonly
are actuated by bicycle hand-brake levers which are
prone to accidental operation. It is to be noted that
for reasons of cost and strength the components of the
pole assembly are made of metal, e.g., aluminum and
steel. However, the pole 954 and isolator member g80
is made of plastic in order to electrically insulate
the trigger actuator from the cam assembly.
HMH-77
