US3110222A

US3110222A - Gas assist system for recoil actuated firearms

Info

Publication number: US3110222A
Application number: US185486A
Authority: US
Inventors: Earle M Harvey
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-04-05
Filing date: 1962-04-05
Publication date: 1963-11-12
Anticipated expiration: 1980-11-12

Description

E. M. HARVEY 3,110,222

GAS ASSIST SYSTEM FOR RECOIL ACTUATED FIREARMS Nov. l2, 1963 3 Sheets-Sheet 1 Filed April 5, 1962 INI/NTOR.- Emi E M I-Iurvlgy E. M. HARVEY Nov. 12, 1963 GAS ASSIST SYSTEM FOR RECOIL ACTUATED FIREARMS Filed April 5, 1962 3 Sheets-Sheet 2 1N VEN TOR. Earle M Hurv ey 74, @momma SEL/M2 Nov. 12, 1963 E. M. HARVEY 3,110,222

GAS ASSIST SYSTEM FOR RECOIL ACTUATED FIREARMS Filed April 5, 1962 5 Sheets-Sheet 5 INVENTOR. T Emi@ M Hmvv En BY I 8 j fsmaQ/mf Unite States 3,110,222 GAS ASSIST SYSTEM FR RECEL ACTUATEED FIREARMS Earle M. Harvey, Agawam, Mass., assigner to the United States of America as represented by the Secretary of the Army Filed Apr. 5, 1962, Ser. N 185,@86 2 claims. (ci. s9-rs9) (Granted under Title 35, US. Code (1952), sec. 266) in the barrel by discharge of the cartridges is oftentimes insufficient to energize the guns operating mechanism. Therefore, an .assist must be provided by adding a booster which utilizes gas pressure to impart additional energy to the banrel.

These boosters are conventionally mounted on the front end of a barrel jacket which is ixed to the gun receiver so as to inclose the barrel. The discharge gases are partially intercepted by an `annular pocket in the booster so as to act rearwardly against the front end of the barrel to supplement the recoil energy transferred thereto. These boosters, which require the support of a barrel jacket, make it difficult and generally impossible to mount a front sight and other accessories on the muzzle of the gun. Moreover, these Aboosters have a tendency to be fouled by copper and carbon build-up to the extent that the barrel is blocked against reciprocation.

In the application for a Machine Gun Seleotively Operated by a Gas or Recoil System, Serial No. 185,485, filed April 5, 1962 by lohn L. Lochhead, there is taught a machine gun which is selectively operated by either a gas system or a recoil system. However', when the cartridges utilized by su-ch gun are of low-energy types, the recoil force imparted to the barrel is insutcient to operate the gun. Consequently, gas assist must be provided. The conventional igas booster is not practical with this gun, which is adaptable for hand tiring, because a barrel jacket would add to the weight and the bulk of the weapon and would intenfere with the mount-ing of a iirst sight and other accessories on the muzzle end of the banrel.

It is, therefore, one object of this invention to provide for such recoil-operated guns a gas assist device which will not interfere with the installation of a sight or other accessory on the -front end of the gun barrel.

lt is another object of this invention to provide such a gas assist device which will bleed gases from the gun barrel midway along the length thereof where the gases are the hottest to reduce considerably any build-up of copper and carbon deposits.

It is a further Iobject of this invention to enlarge the scope of the aforementioned machine gun by adapting it for use with cartridges which are of low-energy types.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a partially cross-sectioned side view of the rear portion of the machine gun with the bolt in battery position;

FIG. la is a forward continuation of FIG. 1 and shows the selecto-r indexed in position for operation of the machine gun by gas means;

FIG. 2 is an elevational View of the front portion of the receiver showing the selector indexed lfor gas operation of the machine gun and the barrel in the battery position;

FIG. 3 is a longitudinally cross-sectioned View of the rear portion of the machine gun and shows the bolt in recoil position;

lFIG. 4 is a view taken along line 4 4 of FIG. 2;

FIG. 5 is a view taken along line 5 5 of FIG. 4;

FIG. 6 is a view taken along line 6 6 of FIG. 4;

FIG. 7 is a forward extens-ion of FIG. 3 and shows the selector indexed in position for operation of the machine gun by gas assist recoil means;

FIG. 8 is a view similar to HG. 2 but showing the selector indexed for gas assist recoil operation of the machine gun and the barrel in the driving position;

FIG. 9 is a view taken along line 9-9 of FIG. 8;

FIG. 1'0 is a view taken along line litt-110 of FIG. 9;

FIG. 1l is a View taken along line 11 1.1 of FIG. 9; and

FlG. 12 is an exploded perspective view of the selector.

Shown in the iigures is a machine gun 1,2r which is selectively operable by gas pressure or recoil forces such as is disclosed in the application for a Machine Gun Selectively Operated by a Gas or Recoil System, Serial No. 185,485, led April 5, 1962 by lohn L. L'ochhead. Machine gun 12, is adapted for automatically firing a small caliber cartridge 14 which is of 7.62 caliber, or the like, and includes a receiver 16 in which a bolt assembly 18 is mounted for sliding reciprocation between a forward locked position and a rearward recoil position. A barrel assembly 20' is journalled in the front end of receiver 16 for longitudinal reciprocation between a forward battery position and a rearward driving position.

Barrel assembly 2li includes a barrel 22, the front portion of which extends forwardly `from receiver `16, and a

gas cylinder assembly

2,4 which includes a gas cylinder 26 and a cooperating piston 2.8. Gas cylinder 25 includes a central body portion 29 which is bracketed to barrel Z2 approximately midway the length thereof so that the gas Icylinder is located within receiver 16. A cylindrical hole 3@ extends laterally thnough body portion 2,9 and communication is provided between suoh hole and bore 31 of barrel 22 by a vertical passageway 32. Piston 2S is slidingly mounted in a bore 34 which extends forwardly in gas cylinder 26 from the rear end thereorf to an end wall '36 located rearwardly of hole 30. A gas port dit extends forwardly from end wall 316 so as to provide communication between bore 34 and hole Sil.

Extending integrally .forward from body portion 29 is a cylindrical piston portion i2 which is smoothly machined around the outside. A concentric bore 44 extends forwardly through piston portion i2 from hole 3i? and such piston pontion is received by a mating chamber 46 in a cylinder block 4S. which is fixed to receiver 16. A close sliding lit is provided between piston portion 4.2, and the wall of chamber 46 so as `to eliminate as much as possible gas leakage thereby. Lf necessary, gas seal rings can be installed on piston portion 4t2.

A selector Sil is rotatingly received by a hole 3ft so as to be selectively indexed in a Gas position or a Recoil position. Selector Sil includes a cylindrical rod 52 received yby hole 3d and such rod extends from opposite sides of body portion 29 to form an extending end 54 on the left side of gas cylinder 26 and another extending end 56 on the right side thereof. Provided in rod 52 is a first aperture 58 and a second aperture `60 which are radially disposed apart so as to converge at the center of the rod. When selector 5d is indexed in the Gas position, first aperture 53 is in registry with gas port 40 and second aperture 6d is in registry with passageway 32 so that discharge gases are directed from bore 31 of lbarrel 22 to bore 34 to act upon piston 2S. When selector 50 is indexed in Recoil position by 90 rotation of the selector in a clockwise direction, looking towards the right side of machine gun 12 and as shown in FIG. la, first aperture 58 is in registry with passageway 32 and second aperture 6!` is in registry with bore 44 so that discharge gases are directed from bore 3d of barrel Z2 into chamber 46.

Extending end 54 on the left side of selector 50 is slabbed off at diametrically opposed sections to form an ear 62 which is symmetrical to the lateral plane which is coincident with the main axis of first aperture 58. When selector 56 is indexed in the Recoil position so that the longest axis of ear 62 is longitudinally disposed, the ear is receivable by a mating longitudinally disposed channel 64 in receiver f6 and is slidable along the channel during reciprocation of barrel assembly 20 `to and from the driving position. Channel 64- has a width similar to the short axis of ear 62 and is interrupted by an oval recess 66 which is located so as to be in registry with selector Stl when barrel assembly 26 is in the forward battery position. Recess 66 has a radius similar to that of rod 52 so that the selector is free to be rotated between the Gas and Recoil positions when barrel assembly Ztl is in battery position.

Extending end 56 on the right end of selector 50` extends through receiver 16 and provided on such extending end is a button 68 which provides means `for manually rotating the selector. Extending end S6 is interrupted by a pair of diametrically opposed segmental cuts 7Gl which form a key section '/"2 which is coincidental with the same lateral plane as ear 62. Key section 72 is slidingly receivable by a slot '74 in the right side of receiver 16 to permit reciprocation of barrel assembly 2d when the long axis of the key section is in alignment with such slot. The width of slot '74 is similar to the short axis of key section '72 and such slot is interrupted -by a circular orifice 76 which is arranged to be in registry with selector 5G when barrel assembly 26 is in battery position and which has a radius similar to that of rod 52. Thus, when selector t) is in Recoil position, key section 72 is in alignment with slot 74 and ear 62 is in alignment with channel 64 so that barrel assembly 20 is free to reciprocate between the battery and driving positions. When selector 5G is rotated to the Gas position so that the long axes of ear 62 and key section 72 are vertically disposed, barrel assembly is blocked in battery position because of the cooperation of the ear with the walls of recess 66 and of the key section with the wall of orice 76.

As disclosed in the aforementioned patent application, bolt assembly 18 includes a carrier Sil, a bolt 82, which is mounted thereon for relative rotational and longitudinal displacement, and cam means 84 operationally disposed between the carrier and bolt for converting relative longitudinal displacement of the -bolt and carrier to rotational displacement of the bolt so that the lbolt is locked to the barrel during forward displacement of the carrier relative to the bolt and is unlocked during rearward displacement of the carrier relative to the bolt. An accelerator 86 is pivotally mounted in receiver 16 and is arranged according to conventional design to accelerate bolt assembly 13 to the rearward recoil position when barrel assembly is adjacent its driving position. A driving rod 8S extends forwardly from carrier 80 so as to be contactable by piston 28 to transfer the energy applied thereto by gases bled from the bore of barrel 22 to the carrier.

Thus, when machine gun 12 is to be operated by gas means, selector 50 is indexed in the Gas position, which is identifiable by the marking of Gas on the right side of receiver 16 and an arrow on button 68. With selector 5t) in the Gas position, ear 62 and key section 72 are positioned in recess 66 and orifice 76, respectively, to block displacement of barrel assembly 2t)y `from battery position and first aperture 58 is in registry with `gas port 40 and second aperture 66 is in registry with passageway 4 32 so that discharge gases are transferable from the bore of barrel 22 into bore 3d to act against piston 28.

iVhen machine gun l2 is to be operated by recoil energy in barrel assembly 20, selector S0 is indexed in the Recoil position which is identifiable by the marking of Recoil on the side of receiver 16 and an arrow on button 63. With selector Sti in the Recoil position, ear 62 and key section 72 are respectively aligned with channel 64 and slot '74 so as to be receivable thereby and, consequently, barrel 2t) is free to reciprocate to and from driving position. Also, first aperture 58 is in registry with passageway 32 and second aperture 6d` is in registry with bore 44 so that, when cartridge M- is discharged in barrel 22, barrel assembly 20 is energized by the recoil forces and, when the projectile of the cartridge passes passageway 32, gases are bled from the bore of the barrel through bore 4d into chamber 46. The gases received by chamber 46 add to the recoil energy in barrel assembly 2t? so that suicient energy is imparted thereto to drive bolt assembly 1S to the recoil position and perform its operating functions.

From the foregoing it is clearly apparent that there is provided herein for recoil operated firearms a gas assist system which is ideally suited to those firearms which are hand fired as the device adds little weight and bulk to the firearms and the muzzle end of the barrel is free for the mounting of accessories thereon. Moreover, the gas assist system is an improvement over conventional booster devices as it is not subjectable to copper and carbon buildup.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

l. A machine gun including a receiver, a barrel journaled in said receiver so as to be movingly responsive to recoil energy produced in said barrel by discharge of a cartridge therein, a bolt assembly mounted in said receiver for reciprocation therein, accelerator means for transferring energy from said barrel to said bolt assembly for reciprocation thereof, a gas cylinder ixedly mounted on said barrel, a passageway arranged between said gas cylinder and said barrel for bleeding gases therefrom into said gas cylinder, and means disposed in cooperation with said gas cylinder for selectively blocking said barrel against displacement and utilizing the gases bled from said barrel to energize said bolt assembly for reciprocation and for selectively releasing said barrel for reciprocation and utilizing the gases bled from said barrel for supplementing the recoil energy in said barrel to provide suflicient energy in said barrel for reciprocating said bolt assembly when transferred thereto by said accelerator means.

2. A machine gun including a receiver, a bored barrel journaled in said receiver so as to be movingly responsive to recoil energy produced in said barrel by discharge of a cartridge therein, a bolt assembly mounted in said receiver for reciprocation therein, accelerator means mounted in said receiver so as to transfer energy from said barrel to said bolt assembly for reciprocation thereof, a gas cylinder fixedly mounted on said barrel, a passageway arranged between said gas cylinder and said barrel for bleeding gases therefrom into said gas cylinder, a bore in said gas cylinder, a piston slidingly mounted in said bore and arranged to be actuatable against said bolt assembly by gases received by said bore, a hollow piston portion on said gas cylinder, a cylinder block fixed to said receiver and provided with a chamber for slidingly receiving said piston portion, a hole extending laterally through said gas cylinder, conduit means extending between said hole and the inside of said barrel, between said hole and said bore in said gas cylinder and between said hole and the inside of said piston portion, a selector mounted in said hole for rotation between a iirst position 5 6 and a second position, aperture means arranged in said when said selector is in the rst position and for releasselector completing communication between said barrel ing said barrel for displacement when said selector is in and said bore in said gas cylinder for passage of gases the second position. thereinto when said selector is in said rst position and for completing communication between said barrel and 5 References Cited in the file 0f this patent the inside of said piston portion when said selector is in UNITED STATES PATENTS the second position, and cooperating means in said selector

Claims

1. A MACHINE GUN INCLUDING A RECEIVER, A BARREL JOURNALED IN SAID RECEIVER SO AS TO BE MOVINGLY RESPONSIVE TO RECOIL ENERGY PRODUCED IN SAID BARREL BY DISCHARGE OF A CARTRIDGE THEREIN, A BOLT ASSEMBLY MOUNTED IN SAID RECEIVER FOR RECIPROCATION THEREIN, ACCELERATOR MEANS FOR TRANSFERRING ENERGY FROM SAID BARREL TO SAID BOLT ASSEMBLY FOR RECIPROCATION THEREOF, A GAS CYLINDER FIXEDLY MOUNTED ON SAID BARREL, A PASSAGEWAY ARRANGED BETWEEN SAID GAS CYLINDER AND SAID BARREL FOR BLEEDING GASES THEREFROM INTO SAID GAS CYLINDER, AND MEANS DISPOSED IN COOPERATION WITH SAID GAS CYLINDER FOR SELECTIVELY BLOCKING SAID BARREL AGAINST DISPLACEMENT AND UTILIZING THE GASES BLED FROM SAID BARREL TO ENERGIZE SAID BOLT ASSEMBLY FOR RECIPROCATION AND FOR SELECTIVELY RELEASING SAID BARREL FOR RECIPROCATION AND UTILIZING THE GASES BLED FROM SAID BARREL FOR SUPPLEMENTING THE RECOIL ENERGY IN SAID BARREL TO PROVIDE SUFFICIENT ENERGY IN SAID BARREL FOR RECIPROCATING SAID BOLT ASSEMBLY WHEN TRANSFERRED THERETO BY SAID ACCELERATOR MEANS.