Note: Descriptions are shown in the official language in which they were submitted.
1 1 623~2
This application is a division of application
Ser, No. 376,321, filed April 27, 1981.
The present invention relates to powder-actuated
tools and, more particularly, to means for adjusting the
power level of indirect-acting power actuated fastener
driving tools.
Powder-actuated fastener driving tools, of the
indirect-acting type, comprise, in general, a piston, the
rear end of which slides into an expansion chamber for the
gases produced by the combustion of the propelling charge.
It is known in the art to continuously adjust the
power level of such tools by modifying the initial volume
of the expansion chamber through relative axial displace-
ment of two chamber-defining tool parts. Such a displace-
ment may for example, be realized by screwing one part,
including the cartridge chamber, onto another part which
includes stop means defining the piston battery position.
It is also known in the art to provide a safety
interlock, for such tools, preventing tool discharge unless
the tool muzzle is firmly pressed against the work piece,
Such an interlock may, for example, be realized by a barrel
slideably carried in the tool receiver and biased toward a
forward or loading position, and a firing mechanism
operable only when the barrel is in a rearward or battery
position. Further, the receiver, which is telescoped over
the barrel, may be adapted to limit access thereto, such
that rearward displacement of the barrel may be accomplished
only when the tool is substantially perpendicular to the
wor~ surface. This feature is commonly known as angle-fire
control and is intended to prevent discharge of the tool
under conditions wherein ricochet of the fastener may occur.
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Unfortunately, the above-described power adjust-
ment technique aliers the axial relation of the barrel and
the receiver. It is, therefore, presently impossible to
incorporate in such a tool, both the power adjustment and
constant angle-fire control features.
It is a primary object of the present invention
to provide an improved indirect-acting powder actuated tool,
incorporating an angle-fire control, wherein the power level
is continuously variable.
In accordance with a particular embodiment of the
invention there is provided an improved powder-actuated
fastening tool. The tool includes a piston and driving
mean~ employing a constant-power powder load to displace
the piston a constant predetermined distance so as to
drive a fastener into a work surface. Power adjustment
means are provided for adjusting the power level of the
driving means while maintaining a fixed gas flow path
through the tool. Firing means are provided for activating
the driving means, the firing means being operable solely
when the tool is pressed against the work surface with
the longitudinal axis of the piston substantially perpen-
dicular thereto, and further being operably independent of
the power level setting of the power adjustment means,
In accordance with a further embodiment of the
invention there is provided a power actuated tool. The
tool includes a means fcrming a barrel having a bore and
means forming a firing chamber communicating with a breech
end of the barrel bore, A fastener-driving piston is
reciprocally slidably disposed in the barrel bore for
movement between a breechward battery position and a muzzle-
ward driven position. ~top means are provided in the
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barrel bore for contacting a breechward surface on the piston
to define the battery position of the piston. Means forming
a muzzle end of the tool are provided for positioning against
a work surface preparatory to driving of a fastener by the
tool and means are provided for cocking the tool for firing
when the muzzle end of the tool is pressed against a work
surface. Angle-fire control means are operably associated
with the muzzle end of the tool in a predetermined relation-
ship for enabling cocking of the tool only when the axis of
the barrel is substantially perpendicular to a work surface.
power control means are provided for axially displacing
the stop means whereby a breechwardmost surface of the
piston can be variably spaced from the firing chamber when
the piston is in the battery position whilç maintaining the
predetermined relationship between the angle-fire control
means and the muzzle end of the tool to provide substan-
tially constant angle-fire control at all power levels of
the tool.
Thus, in general, the tool includes a barrel and
a barrel breech which are adjustably screwed together and
telescopically carried by a slide assembly which, in turn,
is telescopically carried by the tool receiver. More
specifically, the slide assembly and the barrel are oper-
ably connected for corotation, whereby rotation of the slide
assembly produces a joint axial displacement of the barrel
and the slide assembly, relative to the barrel breech,
nevertheless, are axially displaceable, relative to the
sleeve assembly, between a loading position and a battery
position. Thus, the axial relation between the slide
assembly and the barrel is preserved during power level
adjustment and this constant relationship is utilized to
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1 ~ 62352
effect angle-fire control by means of a firing mechanism
which is operable solely when the barrel and the barrel
breech are in the battery position. Further, the ability
of the tool to accept fasteners of differing lengths is
unaffected by power adjustment. Means are provided biasing
the barrel and the barrel breech toward the loading position,
it being possible to overcome the biasing means by pressing
the barrel muzzle against the work surface, while the tool
is substantially perpendicular thereto.
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Brief Description Of The Drawing
The above and other objects, as may hereinafter appear,
may be more clearly understood by reference to the following
detailed description of the preferred embodiment, the appended
claims and the drawing wherein:
Figure 1 is a side cross-sectional view of an indirect-
acting powder-actuated fastener driving tool, arranged and
constructed in accord with the present invention, wherein`the
barrel and barrel breech are in the loading position and
adjusted for maximum power output;
Figure 2 is a fragmentary top cross-sectional view of the
tool of Figure l;
Figure 3 is a side cross-sectional view, similar to Figure
1, showing the tool in condition ready to be fired; and
Figure 4 is a side cross-sectional view similar to Figure
l,wherein the tool is adjusted for minimum power output.
Description Of The Preferred Embodiment
In the drawing, there is shown an indirect-acting powder-
actuated fastening tool including a barrel 1 having a longitu-
dinal bore la, a breech end lb and a muzzle end lc. A piston
3, having a head 3a, is slidably disposed within the barrel
bore la. A barrel breech 5 is threadedly carried on the breech
end lb of the barrel 1 and includes a cartridge-receiving
chamber 5a communicating with a gas expansion chamber 5b
adapted to receive a portion 3b of the piston head 3a in gas-
tight sliding rela~ion. An inwardly projecting lip ld is
provided, proximate the breech end lb of the barrel 1,
cooperating with a second portion 3c of the piston head 3a to
limit its motion toward the cartridge-receiving chamber 5a.
A slide assembly 7 is telescoped over the barrel 1 and
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the barrel breech 5, both of which are jointly axially
~isplaceable, relative to the slide assembly 7, between a
:forward or cartridge loading position, as seen in Figure 1 and
a rearward or battery position, as seen in Figure 3.
A barrel sleeve 9 is disposed intermediate the muzzle end
lc of the barrel 1 and the slide assembly 7, both of which are
operatively connected, for reasons which will be more fully
explained hereinafter, by means of a key 11, slidably carried
in a longitudinal slot 9a in the barrel sleeve 9. Key 11
includes portions lla and llb extending into longitudinal slots
le and 7a in the barrel 1 and the slide assembly 7, respectively.
~~ A spring retaining ring 12 secures the key 11 against accidental
dislodgement, The barrel sleeve 9 is operably connectable to
the barrel 1, during rearward repositioning of the piston 3,
by means of a ball 13, carried in a bore 9b in the barrel sleeve
9, extendable into a recess lf in the barrel 1.
A receiver sleeve 15 is disposed intermediate the breech
end lb of the barrel 1 and the slide assembly 7 and is threadedly
carried on the barrel sleeve 9.
A slide assembly 7 is telescoped into the tool receiver 17,
to which the receiver sleeve 15 is threadedly connected. A
retaining screw 19 secures the receiver sleeve 15 against
being unscrewed from the receiver 17 during operation of the
tool and, more importantly, it engages a slot 5c in the barrel
breech 5, whereby the same is prevented from rotating relative
to the receiver 17.
The receiver 17 also supports a firing mechanism including
a cocking slide 21, disposed rearwardly of the barrel breech 5,
axially displaceable between a forward position, and a rear-
ward, or cocked position, pursuant to displacement of the
1 ~ 62352
barrel 1 and the barrel breech 5 from the cartridge loading
position to a battery position. A helical barrel spring 23
biases the cocking slide 21 toward the forward position and
further serves to bias the barrel 1 and the barrel breech 5
toward the cartridge loading position.
A rebounding firing pin 25, mounted on a firing pin
slide 27, is biased toward contact with a cartridge C by a hel-
ical firing pin spring 29. A spring-loaded firing pin pawl 31,
carried by the firing pin slide 27, engages the cocking slide
21.
A trigger bar 33, operatively connected to a trigger
34 is disposed to rotatably displace a spring-loaded sear 35 to
disengage the firing pin pawl 31 from the cocking slide 21 when
the latter is in the cocked position.
Forwardly of the barrel 1, and concentric therewith,
the barrel sleeve 9 supports a buffer housing 37 carrying an
elastomeric buffer 39 adapted for cooperation with the portion
3c of the piston head 3a consequent to discharge of the tool.
A tiltable muzzle bushing B of the type described
in United ~tates patent 4,210,267, Combette et al, issued July
1, 1980, is preferably carried by the slide assembly 7, forwardly
of the buffer housing 37, and includes a member b which con-
stitutes, in effect an axially displaceable extension of the
barrel 1 and a muzzle bushing cam c which is fastened to the
barrel sleeve 9.
As shown in Figure 1, the tool is adjusted for maximum
power output, with the barrel 1 screwed against the barrel
breech 5. The initial volume of the gas expansion chamber 5b
is, thus, at a minimum, while the length of the power-stroke,
i.e. the distance that the piston must travel ~efore the ex-
pansion gases may escape around the piston head, is a maximum.
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235~
It is to be noted that the bore diameter of the passage past
l-he barrel lip ld is significantly grea~er than the diameter
of the gas expansion chamber 5b, whereby the power stroke
terminates at the chamber mouth. The barrel 1 and the barrel
breech 5 are shown in the cartridge-loading position, while the
cocking slide 21 and the firing pin slide 27 are in the forward
position.
In Figure 3, the tool has been cocked, preparatory to
discharge, by pressing the muzzle end bushing member b against
the work surface S. The barrel 1 and the barrel breech 5 have
thus been axially displaced, against the influence of the
f cocking slide spring 23, to the battery position, whereat the
cartridge receiving chamber 5a has telescoped over a cartridge
C, while the cocking slide 21 and the firing pin slide 27
have been displaced to the cocked position. In this regard,
it will be readily appreciated that the diameter of the slide
assembly 7 is such as to preclude full displacement of the
aforementioned parts unless the tool is substantially perpen-
dicular to the work surface S.
In Figure 4, the tool is shown adjusted for minimum power
output, with the barrel 1 unscrewed from the barrel breech 5,
whereby the initial volume of the gas expansion chamber 5b is
at a maximum and the length of the power stroke is at a
minimum.
Power adjustment is effected by rotation of the slide
assembly 7, which, acting through the key 11, causes the
corotation of the barrel sleeve 9 and the barrel 1, relative
to the barrel breech 5 and the receiver sleeve 15. This
relative rotation results in the desired axial separation of
the barrel 1 and the barrel breech 5, while, at the same time,
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effecting a corresponding axial separation of the barrel sleeve
9 and the receiver sleeve 15. It is, at this point, to be
understood that the screw connections between the barrel 1
and the barrel breech 5 and between the barrel sleeve 9 and the
receiver sleeve 15 have the same thread pitch.
As the barrel 1 and the barrel sleeve 9 are displaced away
from the barrel breech 5 and the receiver sleeve 15, they
correspondingly displace the muzzle bushing B and the slide
assembly 7. Thus, the axial relation between the slide assembly
7 and the barrel 1 and bushing member b is undisturbed by power
level adjustment of the tool, whereby the angle-fire control
~- is maintained.
' It is, thus, to be noted that power adjustment does not
change the length of piston travel during firing and does not
affect the capacity of the tool to accept fasteners of different
lengths.
To disassemble the tool, as for cleaning, the retaining
screw 19 is removed, freeing the barrel breech 5 for corotation
with the barrel 1. The entire barrel/slide assembly, less the
receiver sleeve lS which remains attached to the receiver 17,
is now unscrewed from the receiver 17 by rotation of the slide
assembly 7. The slide assembly 7 is moved to its extreme
forward position, allowing removal of the retaining ring 12
from the barrel sleeve 9. The key 11 is now removed and the
barrel 1 and barrel breech 5 are withdrawn from the barrel
sleeve 9, as may the buffer housing 37 and the buffer 39. The
piston 3 is now slide from the barrel 1 and the barrel 1 and
barrel breech 5 are unscrewed. Lastly, the muzzle bushing
cam c is removed from the barrel sleeve 9, allowing removal
of the barrel sleeve 9 from the slide assembly 7.
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Reassembly is essentially accomplished in reverse order
of disassembly, it being necessary, however, to insure that
the retaining ring 12 does not overlie the ball 13 and that
the tool parts are properly set prior to lockup. This may be
readily accomplished by screwing the barrel 1 completely into
the barrel breech 5. The barrel/slide assembly is inserted
into the receiver sleeve 15 and screwed to its furthest
breechward position and then backed off suficiently to permit
insertion of the retaining screw 19 in the slot 5c in the barrel
breech 5.
While reference has been made above to a particular
embodiment of the inven~ion, various alterations and modifica-
tions ~Jill readily suggest themselves to those skilled in the
art. Accordingly; the scope of this invention is intended to
be limited solely by the following claims.
