U.S. patent number 3,759,135 [Application Number 05/197,178] was granted by the patent office on 1973-09-18 for semi-automatic shotgun.
This patent grant is currently assigned to Ithaca Gun Company, Incorporated. Invention is credited to James Tollinger.
United States Patent |
3,759,135 |
Tollinger |
September 18, 1973 |
SEMI-AUTOMATIC SHOTGUN
Abstract
In the particular embodiment of the invention described herein,
a semi-automatic shotgun is provided with a piston which is
independently movable in a cylinder to drive the action of the gun
rearwardly, a single cartridge stop normally retaining cartridges
in a magazine and released by rearward motion of the action, and a
carrier latch which slides rearwardly to release the carrier when
the cartridge being chambered is fully disposed on the carrier,
thereby permitting that cartridge to retain other cartridges in the
magazine until the cartridge stop is restored to its cartridge
blocking position. To chamber the cartridge, a rotatable breech
block is rotated from its open to its locked position by axial
motion of a bolt support extending through a cam slot in the
bolt.
Inventors: |
Tollinger; James (Ithaca,
NY) |
Assignee: |
Ithaca Gun Company,
Incorporated (Ithaca, NY)
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Family
ID: |
26892626 |
Appl.
No.: |
05/197,178 |
Filed: |
November 9, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
864446 |
Oct 7, 1969 |
3680433 |
Aug 1, 1972 |
|
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Current U.S.
Class: |
89/33.1 |
Current CPC
Class: |
F41A
5/18 (20130101); F41A 9/18 (20130101) |
Current International
Class: |
F41A
5/00 (20060101); F41A 9/00 (20060101); F41A
9/18 (20060101); F41A 5/18 (20060101); F41c
013/00 () |
Field of
Search: |
;42/17,21
;89/33R,33B,191R,191A,192,193 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bentley; Stephen C.
Parent Case Text
This is a division of application of Ser. No. 864,446 filed Oct. 7,
1969, now U.S. Pat. No. 3,680,433, issued Aug. 1, 1972.
Claims
I claim:
1. In a gas operated firearm having a barrel, a receiver, a
magazine for supplying cartridges in succession to the receiver,
carrier means within the receiver for transferring cartridges
received from the magazine into chambering position, bolt means for
chambering cartridges and closing the breech end of the barrel, and
action slide means for driving the bolt means, the improvement
comprising carrier latch means slidably supported within the
receiver for longitudinal sliding motion therein and including
means forming an aperture, a member projecting from the carrier
means and normally extending through the aperture to retain the
carrier means in cartridge-receiving position, the latch means
responsive to motion of a cartridge from the magazine onto the
carrier means to release the carrier means for transfer of the
cartridge to chambering position and having a portion for enabling
a user to manually disengage the member from the aperture.
2. A gas operated firearm according to claim 1 wherein the latch
means comprises a member extending generally perpendicularly to the
carrier means and a projecting element extending from the member
toward the magazine in position to be engaged by the end of a
cartridge received on the carrier.
3. A gas operated firearm according to claim 1 wherein the carrier
means comprises a member supported for pivotal motion and including
a rotatable dog pivotally attached to the member adjacent to one
end thereof, and a double-acting spring tending to rotate the dog
about its pivot axis and to rotate the carrier member about its
pivot axis.
Description
BACKGROUND OF THE INVENTION
This invention relates to firearms and, more particularly, to a new
and improved gas operated firearm characterized by simplicity of
assembly and operation coupled with durability and precision of
performance.
Heretofore, many arrangements have been devised for imparting
expanding gas energy to the action of a gas operated firearm but in
most instances the imparting mechanism and the action have suffered
from excessive complexity of structure and assembly or limited
durability of components. Similarly, previous arrangements for
releasing cartridges from the magazine of a gas operated firearm
and transporting them to the barrel breech have been complex in
structure and subject to excessive wear or frequent breakage of one
or more of the numerous components involved in the structure.
Accordingly, it is an object of this invention to provide a new and
improved gas operated firearm which overcomes the above-mentioned
disadvantages of the prior art;
Another object of the invention is to provide an improved gas
operated firearm characterized by simplicity of structure and
operation, durability of components and improved reliability and
accuracy.
BRIEF SUMMARY OF THE INVENTION
In accordance with the invention a gas operated firearm having a
cartridge magazine arranged for sequential release of individual
cartridges in response to motion of an action assembly includes a
piston supported for sliding motion, independent of the action
assembly, in a cylinder which receives gases from the barrel of the
firearm, the piston being movable thereby to impart actuating
energy to the action assembly. According to another aspect of the
invention, a carrier assembly positioned to receive cartridges from
the magazine and transport them into chambering position in the
receiver of the firearm includes a longitudinally slidable latch
member arranged to be released upon engagement by a cartridge to
initiate operation of the carrier assembly. A single stop member,
normally retaining the outermost cartridge in the magazine is
released by operation of the action assembly, the succeeding
cartridge being retained within the magazine by engagement with the
outermost cartridge until the carrier assembly is released to
transport that cartridge to the chambering position.
To complete the cartridge chambering operation a breech bolt
supported by the action assembly and formed with helically directed
cam surfaces and axially spaced locking lugs, is rotated by axial
motion of the action assembly, causing the locking lugs to engage
corresponding lugs in a rearwardly extending portion of the barrel.
Finally, the invention encompasses the combination of the foregoing
structural and operational features to provide an overall gas
operated firearm which is simplified in structure and has improved
reliability.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1, comprising FIGS. 1A, 1B and 1C taken together, is a
fragmentary view in longitudinal section taken in a vertical plane
through a representative gas operated semi-automatic shotgun
arranged according to the invention, illustrating the components of
the shotgun in the full recoil position of the action assembly;
FIG. 2 is a fragmentary view in longitudinal section, taken along
the line 2--2 of FIG. 1B and looking in the direction of the
arrows, further illustrating the cartridge stop and carrier latch
arrangements of the shotgun;
FIG. 3 is a fragmentary view in longitudinal section, similar to
that of FIG. 1, showing the shotgun with the carrier assembly in
the cartridge chambering position;
FIG. 4, comprising FIGS. 4A and 4B taken together, is a fragmentary
view in longitudinal section taken along a vertical plane,
illustrating the positions of certain of the shotgun components
when the gun is in battery condition;
FIG. 5 is a cross-sectional view, taken along the line 5--5 of FIG.
1B and looking in the direction of the arrows;
FIG. 6 is a cross-sectional view taken along the line 6--6 of FIG.
1B and looking in the direction of the arrows;
FIG. 7 is a cross-sectional view taken along the line 7--7 of FIG.
3 and looking in the direction of the arrows; and
FIG. 8 is a fragmentary sectional view taken along the line 8--8 of
FIG. 1B and illustrating a representative breech bolt structure
arranged in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the representative embodiment of the invention shown in FIGS. 1
and 2, a semi-automatic shotgun comprises a barrel 10 having a
rearward extension 11 projecting into a receiver 12 which is
affixed in the usual manner to a gun stock 13. A cartridge magazine
14, supported parallel to and below the gun barrel, contains a
plurality of shells or cartridges 15 aligned end-to-end for
successive rearward movement into the receiver and upward transfer
therein into chambering position by a vertically movable carrier
16. An action slide assembly 17 includes a tubular forward portion
18 slidably surrounding the magazine 14, a pair of spaced parallel
arms 19 and 20 extending rearwardly therefrom into the receiver 12
and a bolt support 21 connected to the arms 19 and 20 and extending
upwardly therefrom to support a breech bolt 22.
A compression spring 23 disposed within a cylindrical housing 24
within the gun stock 13 urges the entire action assembly 17
forwardly by way of a plunger 25 and a link member 26, the link
being attached by a pivot 27 to the bolt support 21. The receiver
also includes a buffer 28, composed of nylon or similar shock
absorbing material, which is engaged by the bolt 22 to absorb the
impact of the action assembly at the end of its rearward
motion.
The rearward motion of the action assembly is effective to cock the
hammer 29 of the gun in a conventional manner, the hammer being
released to fire the gun by the trigger 30 which is pivotally
supported in a trigger housing 31. In addition, the carrier 16,
which is supported for pivotal motion in the receiver by a pivot
32, carries a rotary dog 33 which is urged by a spring assembly 34
about its pivot 35 in the clockwise direction as viewed in FIG. 1.
As the action slide moves rearwardly it rotates the dog 33
counterclockwise so that, when the carrier 16 is released in the
manner described below, the spring 34 causes the dog to rotate
clockwise, lowering the rearward end of the carrier and raising the
forward end so as to transport a cartridge to chambering position.
When the dog 33 is released by forward motion of the action
assembly the spring 34 urges the rear end of the carrier 16
upwardly, causing the forward end to be restored to the cartridge
receiving position.
In accordance with the invention, the action slide assembly 17 is
driven rearwardly after each firing operation by a piston member
which is movable within a gas cylinder independently of the action
assembly. As best seen in FIGS. 1 and 4, a gas cylinder 36, affixed
to the barrel 10, is closed at its forward end and communicates
with the bore of the barrel through a gas intake port 37. A piston
38 is slidably supported within the cylinder 35 and carries a nylon
buffer member 39 for engagement with the front wall of the magazine
housing 14 in its rearmost position shown in FIG. 1. A gas exhaust
port 40 is positioned in the cylinder 35 to be exposed with piston
38 in its rearward position. As is evident from FIG. 4, the piston
engages the forward end 41 of the action assembly when the gun is
in the battery condition and the piston is at the forward end of
the cylinder, thereby assuring prompt initiation of the rearward
motion of the action upon firing of the gun.
As the piston 38 moves rearwardly, the entire operating energy is
imparted to the action slide assembly before the gas exhaust port
40 is exposed, thereby permitting accurate control of the energy
imparted to the action slide assembly for its operation during the
first portion of the piston stroke and assuring complete venting of
the exhaust gases during the remainder of the stroke. In this way,
the energy imparted to the action slide assembly is made
substantially independent of variations in gas pressure in the
barrel during any particular cycle of operation or from one cycle
of operation to the next so that the shotgun components are
protected from excessive strain while sufficient energy for
positive action is assured.
Within the cartridge magazine 14 a magazine spring 43 urges a
cartridge follower 44 in the rearward direction, causing the
cartridges 15 to move rearwardly therein as the preceding
cartridges are released in succession. Whenever a cartridge 15 is
being raised by the carrier 16 to the chambering position, as
illustrated in FIG. 3, and while the gun is in the battery
position, as shown in FIG. 4, the rearmost cartridge in the
magazine is held in position by engagement with an elongated
cartridge stop member 45. As best seen in FIGS. 2, 4, 5 and 7, the
cartridge stop is supported by a pivot 46 within a longitudinal
recess 47 in the right hand wall of the receiver 12, the forward
end of the stop member being biased outwardly by a coil spring
48.
Along its inner surface the stop member is formed with an inclined
ramp 49 terminating in a forwardly facing abutment 50 so that when
the magazine is being loaded the rim of each cartridge 15 can be
moved past the stop by deflecting it outwardly away from the
magazine axis, after which the cartridge is retained in the
magazine by engagement of its rim with the abutment 50 as shown in
FIGS. 3 and 4.
To retract the stop member 45 when a shell is to be released from
the magazine a cam member 51 projecting upwardly from the forward
end of the stop member is shaped so as to be deflected outwardly
into a recess 52 in the receiver by a downwardly projecting portion
53 of the right hand action bar 19, as illustrated in FIGS. 1 and
5, whenever the action assembly is in its rearmost position. To
assure positive engagement of the abutment 50 with the rim of a
cartridge when in the stopping position, a cartridge guide 54,
mounted in the opposite wall of the receiver 12, prevents the end
of the rearmost cartridge in the magazine from being tilted away
from the stop.
In response to the urging of the magazine spring 43 the rearmost
cartridge, when released by deflection of the stop member 45, moves
rearwardly onto the carrier 16 as illustrated in FIGS. 1 and 2. To
hold the carrier in the cartridge receiving position at all times
except when the magazine is being loaded or when a cartridge is
being raised and chambered, a carrier latch member 55 is supported
for sliding motion parallel to the axis of the gun by two
rearwardly extending arms 56 received in corresponding grooves 57
in the trigger block 58. A compression spring 59 urges the latch
member forwardly within a central opening 60 in the carrier 16 and
an aperture 61 in the latch member receives a rearward projection
61 extending from the center of the carrier a short distance into
the opening 60. In this way, the carrier is normally prevented from
moving upwardly in response to external pressure or the spring bias
of the dog 33 when pivoted rearwardly by the action assembly as
shown in FIG. 1.
At its upper end the latch member 55 has a forwardly directed
projection 65 positioned to engage the rear surface of a cartridge
15 just below its center as illustrated in FIGS. 1 and 2. Thus,
when a cartridge 15 being loaded onto the carrier is urged
rearwardly by the magazine spring beyond the position shown in
FIGS. 1 and 2, the carrier latch member 55 will move rearwardly
against the bias of the latch spring 59, releasing the projection
62 from the aperture 61 and permitting the carrier to be moved
upwardly by the rotary bias of the spring 34 on the dog 33. The
sliding support arrangement for the carrier latch assures improved
durability and provides structural simplicity as contrasted with
other latch support mechanisms, such as pivotal mountings.
During this entire operation, the rearmost cartridge remaining in
the magazine is held forwardly of the abutment 50 on the stop
member 45 by the forward end of the cartridge which is being
chambered. As a result there is always sufficient time for the stop
member to be restored to its blocking position before the carrier
is raised to remove the cartridge from engagement with the
cartridge remaining in the magazine. Consequently, there is no
necessity for any complex double stop arrangement to prevent more
than one cartridge from being supplied to the carrier during one
operation. In addition, because the carrier 16 can not be raised
until the cartridge being chambered has engaged the carrier latch,
it is not necessary to provide an excessively strong magazine
spring or any forward motion stop to prevent cartridges in the
magazine from moving forward when the previously chambered
cartridge is fired. Moreover, because the carrier latch projects
downwardly through the carrier opening 16 it may be released
manually, permitting the carrier to be raised for loading of the
magazine. For this purpose, the lower portion 67 of the latch
member may be knurled to facilitate engagement and operation by the
thumb of the user.
As illustrated in FIGS. 5, 6, and 7, the barrel extension 11 is
approximately semi-circular in shape, commencing at an edge 68
adjacent to the top of a cartridge ejection opening 69 in the
receiver and terminating at an edge 70 disposed below the barrel
axis on the opposite side of the receiver. As best seen in FIGS. 1
and 3, the edge 70 of the barrel extension has three rectangular
recesses 71 spaced in the axial direction by approximately equal
segments 72 of the barrel extension. Corresponding lugs 73
extending outwardly from the breech bolt 22, as shown in FIG. 8,
are positioned to be received in the recesses 71 when the bolt is
in battery position, thereby locking the bolt securely.
To accomplish the bolt locking in a convenient and effective
manner, the bolt 22 is formed in its lower surface with a generally
longitudinal slot 74 having opposed helically directed surfaces 75
and 76 and arranged to receive the upwardly projecting bolt support
21 of the action assembly. Accordingly, as the action assembly
moves forwardly from the position shown in FIGS. 1 and 6, retention
of the bolt support 21 at the rear of the slot 74 prevents rotation
of the bolt and permits the bolt projections 73 to move below the
edge 70 of the barrel extension. When the bolt reaches its
forwardmost position, the lugs 73 are aligned with the
corresponding recesses 71 in the barrel extension, thereby
permitting the bolt to rotate to the locked position shown in FIG.
3 as the action assembly moves the bolt support forwardly in the
slot 74 and the support 21 engages the forward helically directed
surface 75. Upon rearward motion of the action assembly, the
helically directed surface 76 is engaged by the bolt support 21,
causing the bolt to rotate in the opposite direction to unlock the
bolt lugs 73 from the barrel recesses 71.
Within the bolt 22 an axially slidable firing pin 77 is urged
rearwardly by a spring 78 and normally projects beyond the rear end
of the bolt so as to be engaged by the hammer 29 when the gun is
fired. In addition, a nylon buffer 79 is positioned within the bolt
to absorb energy transmitted from the action assembly through the
bolt support 21 at the end of its rearward motion.
In operation, therefore, with the gun in battery position, as shown
in FIG. 3, the chambered cartridge is fired, causing gas to pass
from the barrel through the port 37 into the cylinder 35 and drive
the piston 38 and the action slide assembly engaged thereby in the
rearward direction. After the forward end of the piston exposes the
exhaust port 40 and the piston is stopped by the buffer 39, the
action assembly continues rearwardly. When the action assembly
reaches its rearmost position, as shown in FIGS. 1 and 2, the
downwardly projecting portion 53 of the action bar 19 deflects the
stop member 45 to release the rearmost cartridge from the magazine
14. That cartridge, driven rearwardly by the magazine spring 43,
engages the carrier latch projection 65 to disengage the latch from
the carrier 16.
When the latch 55 is released, the carrier is moved upwardly by
rotary motion of the dog 33 under the urging of the spring 34,
which moves the components to the position shown in FIG. 3. This
releases the action assembly and it commences its forward motion in
response to the urging of the action of spring 23. When the carrier
is raised, the action assembly moves the bolt support 21 forwardly,
causing the bolt 22 to chamber the elevated cartridge and rotating
the bolt into the locked position illustrated in FIG. 3. With the
dog 33 released by forward motion of the bolt support 21, the
carrier 16 is pivoted downwardly to the latched position by the
spring 34. At the same time, the piston 38 is carried by the
forward end 41 of the action assembly to its forward position in
the cylinder 35 in readiness for the next cycle of operation.
* * * * *