Note: Descriptions are shown in the official language in which they were submitted.
CA 02237799 1998-08-07
1
BACKGROUND OF THE INVENTION
The invention relates to firearms and more specifically to a
recoil system for the butt stock of a firearm.
One of the age old problems that has existed with firearms
is the fact many of them have a severe recoil that affects the
person firing the weapon. In firearms such as shotguns and
rifles, the rear end of the butt stock is positioned against the
shooters shoulder and the recoil often causes the shooter to
raise the front of the firearm each time the weapon is fired.
Also the amount of recoil varies depending upon the amount of
explosive in the shell being fired and the recoil can result in
pain and or bruising to the shoulder area of the person firing
the weapon. One example of the recoil being detrimental to a
shooter's accuracy is when the firearm is a shotgun being used
for skeet shooting by a man or a woman.
The best prior art recoil systems for the butt stock of a
firearm have been very expensive and the inexpensive systems do
not function properly. Two examples of expensive systems are a
hydro-coil fluid dampening system and a pneumatic air chamber
system. The present day inexpensive recoil systems utilize
compression coil springs to absorb the recoil forces. If the
compression coil spring is a little too strong, you get more
recoil than with a regular firearm. If the compression coil
spring is not strong enough it is worse, in that it gives the gun
some travel and it is the same as holding the butt stock too
loosely.
CA 02237799 1998-08-07
2
It is an object of the invention to provide a novel recoil
system for the butt stock of a firearm that minimizes the amount
of recoil force experienced by the person firing the weapon.
It is also an object of the invention to provide a novel
recoil system for the butt stock of a firearm that minimizes pain
to the shoulder of the person firing the weapon due to recoil
forces.
It is another object of the invention to provide a novel
recoil system for the butt stock of a firearm that requires
limited modification to the butt stock.
It is a further object of the invention to provide a novel
recoil system for the butt stock of a firearm that utilizes an
extension coil spring for the first time.
It is also an object of the invention to provide a novel
recoil system for the butt stock of a firearm that is easily
mounted to the rear end of a conventional butt stock.
SUMMARY OF THE INVENTION
The recoil system for the butt stock of a firearm is
installed in the rear end cavity of a conventional butt stock.
The existing recoil pad is removed and set aside for later
assembly. A recoil suppressor assembly is then attached to the
open end of the butt stock. Attached over the rear end of the
recoil suppressor assembly is a rubber recoil housing and to its
rear wall is then attached the previously removed recoil pad.
CA 02237799 1998-08-07
3
The recoil suppressor assembly has an elongated body portion
with a mounting flange portion extending transversely adjacent
its rear wall. The rear wall of the elongated body portion has a
vertically extending bore hole within which is reciprocally
received a piston ram. The rear end of the piston ram extends
into the bore hole cavity of the recoil housing approximately
1 1/2 inches. The rear end of the piston ram has a pair of
laterally spaced threaded bore holes that receive screws that are
inserted through aligned bore holes in the rear wall of the
recoil housing.
In its static position the piston ram extends from the rear
end of the elongated body portion approximately 1 1/2 inches. As
the firearm is shot, the recoil transmitted through the butt
stock will drive the butt stock and the elongated body portion
rearwardly causing it and the transversely extending mounting
flange portion to travel rearwardly in the bore hole cavity of
the recoil housing. After the butt stock has reached its
rearward position, the extension coil spring structure will
return the elongated body portion to its initial forward static
position.
The elongated extension coil spring is mounted externally of
the elongated body portion. Its front end is secured to a pin or
retainer secured to the front end of the elongated body portion.
The rear end of the extension coil spring is connected to the
front end of the front lever arm. The rear end of the front
lever arm is pivotally secured to the bottom end of the rear
CA 02237799 1998-08-07
4
lever arm: The rear lever arm is positioned substantially
vertically in an aperture in the mounting flange portion of the
body portion and it pivots about a hinge pin positioned
intermediate its top and bottom ends. A roller cam is mounted on
the top end of the rear lever arm and it is captured in a cavity
in the bottom wall of the piston ram. When the recoil action
takes place, the mounting flange portion travels rearwardly
thereby causing the roller cam on the top end of the rear lever
arm to travel forwardly in the cavity in the bottom wall of the
piston ram. After the recoil force has been dissipated, the
extension coil spring causes the rear lever arm to be pivoted
clockwise so that the elongated body portion returns to its
static position.
A first alternative embodiment recoil suppressor assembly
has an elongated body portion with a mounting flange portion
extending transversely adjacent its rear wall. The rear wall of
the elongated body portion has a longitudinally extending primary
bore hole within which a piston ram is reciprocally received. The
rear end of the piston ram extends into the interior chamber of
the tubular bellows recoil housing approximately 1 1/2 inches.
The rear end of the piston ram has a pair of vertically spaced
bore holes that receive screws that are inserted through aligned
bore holes in the rear wall of the tubular bellows recoil
housing. The front end of the tubular bellows recoil housing is
detachably secured to the open rear end of the butt stock. An
elongated extension coil spring is mounted externally of the
CA 02237799 1998-08-07
elongated body portion. The front end is secured to a
transversely extending pin secured to a pair of bifurcated
fingers extending downwardly from the front end of the body
portion. The rear end of the spring is secured to the front end
of a length of motorcycle chain and the rear end of the chain is
secured to the front end of the lever of the cam assembly. The
rear end of the lever has a pair of bifurcated fingers that
receive a roller cam therebetween that is mounted on a
transversely extending pin.
In its static position, the roller is captured in the bottom
end of a cavity formed in the bottom surface of the piston ram.
As the firearm is shot, the recoil transmitted through the butt
stock will drive the butt stock and the elongated body portion
rearwardly causing it and the transversely extending mounting
flange portion to travel rearwardly in the interior chamber of
the tubular bellows recoil housing. As this is happening the
roller cam travels upwardly in the cavity formed in the bottom
surface of the piston ram and the front end of the lever pivots
downwardly and rearwardly approximately 180 degrees and into the
cutout portion formed in the rear wall of the tubular bellows
recoil housing. After the butt stock has reached its rearward
position, the extension coil spring structure will return the
elongated body portion to its initial forward static position.
A second alternative embodiment of the recoil suppressor
assembly also has an elongated body portion with a mounting
flange portion extending transversely adjacent its rear wall.
CA 02237799 1998-08-07
6
The rear wall of the elongated body portion also has a
longitudinally extending bore hole within which a piston ram is
reciprocally received. The rear end of the piston ram extends in
to the interior chamber of the tubular bellows recoil housing
approximately 1 1/2 inches. The rear end of the piston ram is
secured to a transversely extending rear wall. Above and below
the piston ram coil, spring bore holes are formed that extend
from the rear end of the elongated body portion to its front end.
An extension coil spring is positioned in each of these
respective bore holes with their rear ends being rigidly captured
by transversely extending pins in these bore holes. The front
end of the springs are captured by a cylindrical arm extending
transversely from the front end of the piston ram. The front end
of the elongated body portion is open so that when the firearm is
shot, the recoil transmitted through the butt stock will drive
the butt stock and the elongated body portion rearwardly causing
it and the transversely extending mounting flange portion to
travel rearwardly into the interior chamber of the tubular
bellows recoil housing. As this occurs, the piston ram drives
the front end of the respective extension coil spring out through
the open front end of the elongated body portion. After the butt
stock has reached its rearward position, the extension coil
spring structure will return the elongated body portion to its
initial static position.
CA 02237799 1998-08-07
7
DESCRIPTION OF THE DRAWINGS
Figure 1 is an exploded perspective view of the recoil
system and the manner in which it is secured to the rear end of
the butt stock of a firearm;
Figure 2 is a side elevation view with portions shown in
cross-section illustrating the recoil suppressor assembly secured
to the rear end of the butt stock of the firearm;
Figure 3 is an enlarged side elevation cross-sectional view
of the recoil suppressor assembly;
Figure 4 is a rear elevation view of the recoil suppressor
assembly;
Figure 5 is a side elevation view with portions shown in
cross-section illustrating the first alternative embodiment of
the recoil suppressor assembly secured to the rear end of the
butt stock of the firearm when the recoil suppressor assembly is
in its static position;
Figure 6 is a side elevation view of the second alternative
embodiment of the recoil suppressor assembly illustrated in
Figure 5 showing it now in its dynamic compressed position;
Figure 7 is a cross-sectional view taken along lines 7-7 of
Figure 5;
Figure 8 is a rear perspective view of the second
alternative embodiment of a recoil suppressor assembly;
Figure 9 is a side elevation view with portions shown in
cross-section showing the second alternative embodiment recoil
suppressor assembly in its static position; and
CA 02237799 1998-08-07
8
Figure l0 is a side elevation view with portions shown in
cross-section of the second alternative embodiment recoil
suppressor assembly showing it in its dynamic compressed
position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The novel recoil system for the butt stock of a firearm will
now be described by referring to Figures 1-4 of the drawings. In
Figure 1, a firearm 10 (which is normally a shotgun or a rifle)
has a receiver 12 and a conventional butt stock 14. Butt stock
14 has a bore hole 16 through which is inserted the shank of a
bolt 18 whose front end is threadably secured to the rear end of
receiver 12. Cavity 20 receives recoil suppressor assembly 22.
Recoil suppressor assembly 22 has an elongated body portion
24 having an X-axis. Body portion 24 has a front wall 26 and a
rear wall 27. A mounting flange portion 28 extends transversely
to the elongated body portion 24. A bottom bore hole 30 and a
top bore hole 31 align with respective threaded bore holes 32 and
33 in the rear end of butt stock 14 and a pair of screws 35
detachably secure the mounting flange portion 28 to butt stock
14.
A piston ram 37 extends rearwardly from rear wall 27 a
predetermined distance D1 which is approximately 1 1/2 inches.
The front end of piston ram 37 is reciprocally received in bore
hole 39 of body portion 24. There is a transversely extending
bore hole 41 in piston ram 37 and a pin 42 is inserted therein
CA 02237799 1998-08-07
9
and its outer end is captured in a slot 43 in the side wall of
body portion 24 thereby allowing the piston ram 37 to travel
reciprocally forward and backward in bore hole 39. The rear wall
of piston ram 37 has a pair of threaded bores 45 that align with
bore holes 47 in recoil housing 48 and screws 49 secure the two
members together. Recoil pad 51 which originally had been
removed from the rear of butt stock 14 is then secured by screws
53 passing through bore holes 54 in recoil pad 51 and then
threadably received in threaded bore holes 56 in recoil
housing 48.
The front end of body portion 24 has a slot 58 for receiving
a reversible retainer 60. Reversible retainer 60 has a pair of
vertically spaced pin apertures 62 for removably receiving
connecting pins 63. By reversing the orientation of reversible
retainer 6o, either a short spring or a long spring may be
utilized depending upon the need for shells having either high or
low base powder charges. This provides approximately 1 1/2 inch
adjustment for spring changes. Connecting pins 63 would also
pass through aligned respective apertures 65 in the opposite side
walls of body portion 24.
A extension coil spring 67 has its front end inserted into
aperture 68 at the bottom end of reversible retainer 6o. A cam
assembly 70 has a front lever arm 72 and a rear lever arm 73 that
are pivoted together by a pin 74. Lever arm 72 has an aperture
76 formed in its front end for receiving the rear end of
extension coil spring 67. Rear lever arm 73 in its static
CA 02237799 1998-08-07
position normally has its bottom end received within aperture 78
in rear wall 28 and its top end received in cavity 80 in the
bottom wall of piston ram 37. A roller cam 82 is mounted on a
pin 83 passing through the top end of rear lever arm 73.
The manner in which the novel recoil system functions starts
with the piston ram in its static position illustrated in
Figure 2. When the weapon is fired, the recoil of the butt stock
causes it to travel rearward until the rear wall of mounting
flange portion 28 has reached the front surface of the bore hole
cavity 90 in recoil housing 48. As this is occurring, elongated
body portion 24 has also traveled rearwardly so that the front
end of piston ram 37 approaches the front end of bore hole 39.
Rear lever arm 73 at the same time is pivoting around hinge pin
92 and roller cam 82 is traveling the inner surface of cavity 80.
Once the recoil force has been dampened or eliminated, extension
coil spring 67 pulls front lever arm 72 forward and causes rear
lever arm 73 to rotate clockwise back to its original static
position.
The first alternative embodiment is illustrated in Figures
5-7. The structure of the butt stock and the recoil pad are
identified by the same numerals as utilized in the embodiment
illustrated in Figures 1-4. This embodiment has a recoil
suppressor assembly 100 and a tubular bellows housing 102.
Recoil suppressor assembly 100 has an elongated body portion
104 having a front wall 105, a rear wall 106, a primary bore hole
107, a mounting flange 109 and a bottom wall 110. Laterally
CA 02237799 1998-08-07
11
spaced bifurcated fingers 112 extend downwardly from the front
end of body portion 104 and form a slot or channel 114
therebetween. Each of the bifurcated fingers 112 has a bore hole
116 that receives the respective opposite ends of a pin 118. The
laterally spaced vertical left and right side walls 120 of body
portion 104 have an elongated slot 122 in them. The function of
elongated slots 122 will be described later.
A piston ram 130 is telescopically received in primary bore
hole 107 of elongated body portion 104. It has a pair of
longitudinally spaced transversely extending bore holes 132
passing between its vertical side walls and pins 134 extend
outwardly on both sides and are captured in the respective slots
122 of the respective side walls 120. This structure provides a
guide for the travel of the piston ram 130 forwardly and
rearwardly in body portion 104. A cavity 136 is formed in the
bottom wall of piston ram 130 and adjacent its rear end is a
vertical bore hole 138 having a pin 140 inserted therein and it
performs a function to be described later. A pair of vertically
spaced bore holes 142 are formed in the rear end of piston ram
130 and they each have a cavity 144 for receiving nuts to be
threaded on screws 146.
An extension coil spring 15o has its front end captured by
pin 118 and its rear end is captured in the front end of a length
of motorcycle chain 152. The rear end of chain 152 is secured to
cam assembly 154. Cam assembly 154 has a lever 156 having a front
end 158 and a rear end 159. Lever 156 has a pair of bifurcated
CA 02237799 1998-08-07
12
arms 162 between which is positioned a roller cam 164 that is
mounted on a pin 166. Lever 156 is positioned in an aperture 170
in rear wall 106 of body portion 104. Figures 5 and 6 show the
respective positions of lever 156 when butt stock 14 is at both
its forward and rearward positions. Roller cam 164 is captured
in cavity 136(see Figure 7) and as the rear end of butt stock 14
travels rearwardly, roller cam 164 travels upwardly along the
surface of metal pin 140. Lever 156 has a curved edge 172 that
travels around the bottom end of pin 140 as lever 156 travels
rearwardly to the position illustrated in Figure 6. Extension
coil spring 150 returns lever 156 to the position illustrated in
Figure 5 after the recoil forces have been absorbed.
Tubular bellows recoil housing 102 has an inwardly extending
front flange or lip 174 and an inwardly extending rear flange or
lip 175. Lip 174 is captured between the rear end of butt stock
14 and the front end of mounting flange 109 of body portion 104
and held in position by screws 35. Bellows recoil housing 102 has
an interior chamber 178 and a rear wall 180. Aligned bore holes
142 receive the respective screws 146 to secure piston ram
thereto. Bore holes 184 receive screws 53 to secure recoil pad
thereto.
A second alternative embodiment is illustrated in Figures 8-
10. It has a recoil suppressor assembly 200 having an elongated
body portion 202, a piston ram 204, and a tubular bellows recoil
housing 2o5.
Body portion 202 has a front end 206, a rear end 207, a left
CA 02237799 1998-08-07
13
side wall 208 and a right side wall 209. A mounting flange 212
extends from rear end 207. A primary bore hole 214 extends the
length of body portion 202 and it telescopically receives a
piston ram 204. A pair of coil spring bore holes 218 receive
extension coil springs 220. A cylindrical arm 224 passes
transversely through the front end of piston ram 204 and it
captures the front end of the respective extension coil springs
220. The rear end of these springs are captured by pins 226.
Piston ram 204 has an elongated slot 230 that captures a pin 232
passing through between the side walls 208 and 209. Slot 230 acts
as a guide or track.
Tubular bellows housing 205 has inwardly extending flanges
or lips 240 at its front end and inwardly extending flanges or
lips 242 at its rear end. A plate or wall 250 may be secured to
the rear end of piston ram 204. Screws 35 capture lips 240
between the rear end of butt stock 14 and the front end of
mounting flange 212. Screws 53 capture lip 242 between the rear
end of wall 250 and the front end of recoil pad 51.
