Chambering mechanism for an automatic revolver type gun

Aug. 30, 1960

J. F. O’BRIEN

2,950,652

CHAMBERING MECHANISM FOR AN AUTOMATIC REVOLVER TYPE GUN

Filed Dec. 20, 1957

Sheets-Sheet 1

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Aug. 30, 1960 j. f. O brien 2,950,652

CHAMBERING MECHANISM FOR AN AUTOMATIC REVOLVER TYPE GUN

Filed Dec. 20, 1957 5 Sheets-Sheet 2

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Aug. 30, 1960 j. f. O brien 2,950,652

CHAMBERING MECHANISM FOR AN AUTOMATIC REVOLVER TYPE GUN

Filed Dec. 20, 1957 5 Sheets-Sheet 3

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<img file="US2950652A_D0004.tif" />

Aug. 30, 1960

J. F. O’BRIEN

2,950,652

CHAMBERING MECHANISM FOR AN AUTOMATIC REVOLVER TYPE GUN

Filed Dec. 20, 1957

Sheets-Sheet 4 £ rzf~_ En_

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INVENTOR.

JohnT.D Βτιεπ

BY

Aug. 30, 1960 J. _F. O’BRIEN 2,950,652

CHAMBERING MECHANISM FOR AN AUTOMATIC REVOLVER TYPE GUN

Filed Dec. 20, 1957 5 Sheets-Sheet 5

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S. J- d

United States Patent Office

2,950,652

Patented Aug. 30, 1980

2,950,652

CHAMBERING MECHANISM FOR AN AUTOMATIC REVOLVER TYPE GUN

John F. O’Brien, Springfield, Mass., assignor to the United States of America as represented by the Secretary of the Army

Filed Dec. 20,1957, Ser. No. 704,219

Claims. (Cl. 89—155) (Granted under Title 35, U.S. Code (1952), sec. 266) expended cartridge cases have been extracted and moved out of the way.

A still further object of this invention is to provide such a chambering mechanism with a device for conveying expended cartridge cases from the drum and for releasably holding live cartridge cases therein.

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 chambering mechanism showing a projectile disposed in the top barrel and a cartridge case positioned in the chamber unit rearwardly thereof;

Fig. 2 is a view taken along line 2—2 of Fig. 1 but showing the relationship of the parts after actuation of the ramming mechanism but before rotation of the drum;

Fig. 3 is a view similar to Fig. 2 but showing the chamber unit rotated to the following station;

Fig. 4 is a view taken along line 4—4 of Fig. 2;

Fig. 5 is a reduced exploded view of the chamber mechanism in perspective?

Fig. 6 is a view taken along line 6—6 of Fig. 1;

Fig. 7 is a view taken along line 7—7 of Fig. 6;

Fig. 8 is a view similar to Fig. 7 but showing an ex- pended cartridge case partially moved from the chamber unit into the communicating ejection port;

Fig. 9 is a view similar to Figs. 7 and 8 but showing the incoming expended cartridge case stopped by the stop member;

Fig. 10 is a view taken along line 10—10 in Fig. 7; and

Fig. 11 is an enlarged perspective view of the latch.

Shown in the figures is a substantially U-shaped support 12 provided with a pair of parallelly extending arms 14 the ends of which are secured to diametrically disposed flanges provided on the front end of a cylindrical barrel mount 16 so that such mount extends rearwardly between such arms. A pair of bores 18 are disposed so 40 that the axes therein lie in the vertical plane of the firearm and extend longitudinally through mount 16 to securely receive a pair of barrels 20 so· that the breach ends thereof are flush with the rear end of the mount. Also extending longitudinally through mount 16 is a ₄₅ pair of ejection ports 22 which are more fully described hereinafter.

Rotatably mounted to mount 16 is a drum assembly 24 ( as best shown in Fig. 5) which includes a chamber unit 26 and a cylindrical sleeve 28 of larger diameter ₅₀ which extends forwardly to encircle mount 16. An axle 30 extends axially from the rear and front ends of chamber unit 26 to be rotatably received in mating holes in the base of support 12 and mount 16 respectively for rotatably supporting drum assembly 24, while rollers 55 32 are provided circumferentially around mount 16 to assist in supporting the front end.

Chamber unit 26 is essentially triangular in cross section and provided longitudinally through each of the apexes thereof is a chamber 34 which is axially alignable 60 with the barrels 20 as drum assembly 24 is rotated and such chambers are adapted to slidingly accommodate a cartridge case 36 charged with a propellant. Extending longitudinally along each of the sides of chamber unit 26 is a cylindrical trough 38 provided with a longitudinal mouth portion 40. The walls of the troughs 38 are more than 180 degrees in circumference so that a projectile 42 is slidingly retained thereby, and such troughs are disposed so as to be alignable with the bores of barrels 20 as chamber unit 26 is rotated whereby the projectiles may be slidingly moved from such troughs into the bores of the barrels.

The chambers 34 and troughs 38 are arranged in

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty' thereon.

This invention relates to revolver-type automatic guns and more particularly to the chambering mechanism therefor.

This application is a continuation-in-part of applica. tion Serial No. 536,793, filed September 26, 1955, in the name of John F. O’Brien for “Twin Barrel Revolvertype Gun,” which application is now abandoned.

It is the principal object of this invention to provide a revolver-type automatic firearm which fires at a faster rate than those of conventional design.

It is well recognized that the firing rate of automatic guns may be increased through the simplification of the operating cycle and/or a reduction in the mass of the moving parts, and/or the minimizing of the displacement required of such parts.

The conventional revolver-type gun includes a drum for conveying cartridges to and from a battery station responsive to the reciprocation of an actuator, with the expended cartridge cases being extracted rearwardly from the drum for ejection from the gun. With such guns the firing rate is affected by the mass and length of the drum which in turn determines the mass and linear displacement of the actuator. Also, the loading of live rounds into the drum is necessarily delayed until the expended cartridges are extracted therefrom and moved out of the way. Efforts have been made to decrease the mass of the drum and, consequently, the mass and the displacement of the. actuator through the use of cartridges in which a projectile is telescoped in a cylindrical case to decrease the overall length of the cartridge and, therefore, the length of the drum. This, however, is not completely satisfactory as the diameter of such a cartridge has to be increased to accommodate the necessary propellant charge and such increase requires a corresponding increase in drum diameter, to offset the advantages which are gained from shortening the drum by reducing the length of the cartridges.

It is a more specific object of this invention to provide a chambering mechanism which increases the firing rate of revolver-type automatic guns by providing such guns with a drum assembly which cooperates with a pair of barrels and a ramming mechanism such as is described in applicant’s copending application, Serial No. 536,791, filed September 26, 1955, to convey separate projectiles and cartridges to the barrels and form thereat complete rounds with such chambering mechanism having a minimum mass and displacement of the parts.

Another specific object of this invention is to provide ₍such a gun with a chambering mechanism through which the operating cycle is simplified by having the expended cartridge cases in the drum ejected therefrom by the live cartridge cases rammed thereinto to eliminate the waiting period required in the cyclic operation of conventional revolver-type guns where the ramming of live cartridge cases into the drum must be delayed until the

2,950,652 diametrically opposed pairs so that a chamber and a trough are simultaneously alignable with opposite ones of the barrels 20, and as the chambers and troughs are alternately disposed around chamber unit 26 they are alternately alignable respective to each, one of the barrels when drum assembly 24 is rotated.

Provided around the outside of sleeve 28 is a cam track 44 having cooperation with an actuator 46 as hereinafter described to rotate drum assembly 24 and index chamber unit 26 relative to the barrels 20. Actuator 46 is slidingly disposed for operation in a rearward stroke responsive to gases produced in one of the barrels 20 by discharge of a cartridge case 36 thereinto and a forward stroke responsive to similarly produced gas pressure in the other one of the barrels. Whereby, actuator 46 is moved through a complete cycle by the combined firing of the two barrels 20.

Cam track 44 includes a number of longitudinally disposed linear portions 48 equal to the total number of chambers 34 and troughs 38. The linear portions 48 are slightly longer than cartridge case 36 or projectile 42, whichever is longer, and are disposed around the circumference of sleeve 28 so that when actuator 46 is sequentially engaged therewith the chambers 34 and troughs 38 are sequentially aligned with the barrels 20 whereby a ramming mechanism such as is described in applicant’s aforementioned copending application may move cartridge cases 36 and projectiles 42 from a feeding mechanism (not shown) into position to form a complete round at the breech ends of the barrels 20. The opposite ends of the linear portions 48 are joined by semicircular portions 52 to form a continuous track around sleeve 28. The semicircular portions 52 cooperate with actuator 46 in sequentially rotating drum assembly 24 to succeeding stations while the linear portions 48 cooperate with such actuator to hold drum assembly 24 immovable during the ramming operation.

The ramming mechanism includes a right-hand rammer 54 and a left-hand rammer 56 which are longitudinally actuated by the gas pressure formed in the barrels 20 and are synchronized by conventional means (not shown) to the movement of actuator 46 so as to be simultaneously moved in opposite directions. The right-hand rammer 54 includes three cooperating finger portions. One of these, as noted at 58 in Fig. 2, engagingly moves a projectile 42 from the feeding mechanism (not shown) into the one of the troughs 38 which is positioned in the station immediately adjacent the top battery station on the right side of drum assembly 24. Another finger, noted at 60, simultaneously moves a cartridge case 36 from the feeding mechanism to the chamber 34 which is immediately adjacent the bottom one of the battery stations, also on the right side of the drum assembly. At the same time, the third finger, noted at 62, is extendable through mouth portion 40 to engageably move from such trough into the breech of the bottom one of the barrels 20 the projectile 42 which was previously placed in such trough by finger portion 58. Finger portion 62 is pivotably mounted so as to be cammingly moved out of the mouth portion 40 by engagement with the cooperating wall thereof when drum assembly 24 is rotated.

Left-hand rammer 56 includes three finger portions which correspond to finger portions 58, 60 and 62 and which are arranged to simultaneously move a cartridge case 36 and a projectile 42 into the chamber 34 and trough 38 positioned in their respective charging stations between the top and bottom battery stations on the left-hand side of chamber unit 26 and a projectile into the breech of the top one of the barrels 20 when actuator 46 responds to the discharge of the bottom barrel.

The ejection ports 22 are positioned in barrel mount 16 so as to be axially aligned with the chambers 34 when in the charging stations whereby the expended cartridge cases 64 carried to such charging stations after being discharged in one of the battery stations are movable into such ejection ports and out of the gun by the live cartridge cases 36 being moved into the chamber unit 26 by the ramming mechanism. Each of the ejection ports includes a cylindrical rear portion 66 having a diameter 5 slightly larger than that of cartridge case 36 and a front portion 68 which has a similar diameter and is axially offset from such rear portion. An intermediate oval portion 70 is formed by the injunction of such front and rear portions and a ramp 72 leads from the front end of oval por10 tion 70 to front portion 68 to facilitate the passage of the expended cartridge cases 64 through the ports 22. Front portion 68 is offset from rear portion 66 to provide clearance space for the operation of a stop member 76 arranged as hereinafter described to stop the forward move15 ment of an expended cartridge case 64 into rear portion to prevent the movement of a cartridge case 36 past the front end of the receiving one of the chambers 34 when moved thereinto by the ramming mechanism. Each of the stop members 76 includes an arm portion 78, which 20 is receivable by a groove 74 in radial communication with front portion 68 and oval portion 70, and an extension portion 80 which extends at right angles therefrom contiguous the front end of sleeve 28 for engagement with three equally spaced cams 82 which extend angularly for25 ward from such front end. A pin 84 extends transversely through stop member 76, at the junction of arm portion 78 and extension portion 80, and a lug 86 projecting from the front end of barrel mount 16 to pivotally support such stop member. A coil spring 88 is disposed between the 30 base of groove 74 and arm portion 78 to bias such portion outwardly from such groove and extension portion 80 inwardly toward the end of sleeve 28. When extension portion 80 is in engagement with the end of sleeve 28, the free end of arm portion 78 projects out of groove 74 35 and into position to engage the front end of the expended cartridge case 64 being moved into the ejection port 22 by the rammed cartridge case 36 when the rear end of such expended cartridge case is clear of chamber unit 26. Thus, the cartridge case 36, which is being moved into ⁴⁰ chamber unit 26 and is pushing the expended cartridge case 64 therefrom, is prevented from being positioned too far forwardly to interfere with the rotation of drum assembly 24. The cam portions 82 are so arranged that the arm portions 78 are moved thereby into their respective 45 grooves 74 to free the front end of the expended cartridge case 64 before the chambers 34 carrying the expended cartridge cases are rotated into alignment with their respective ejection ports 22, and so that such arm portions are disengaged from the cooperating ones of such cam 5θ portions when such chambers are aligned with the ejection ports. However, the arm portions 78 are retained in their respective grooves 74 after the disengagement of the extension portions 80 from the cooperating ones of the cam portions 82 through the cooperation of a pair of 55 latches 90.

Each of the latches 90 is substantially L-shaped in configuration as is best shown in Figs. 10 and 11 and is pivotally mounted for transversal movement relative to stop member 76 so as to be movable over the top of arm porβθ tion 78 to releasably retain such arm portion in groove 74 after being pivoted thereinto. The latches 90 are also disposed in the path of the expended cartridge cases 64 when moved from rear portions 66 to front portions 68, as is best shown in Fig. 10, so as to be engageably moved there05 by to unlatch positions. Whereby, the arm portions 78 are released to be biased by the cooperating springs 88 into position to engageably stop -the expended cartridge cases being moved into the ejection ports 22. The latches 90 are held out of latch positions by engagement thereof 70 with the adjacent sides of the arm portions 78 when in the stop positions, and a spring 92 biases each of the latches to the latch position when the cooperating arm portion is pivoted into its respective groove.

Thus, when a cartridge case 36 is fired, for instance, in 75 the top battery position, the resulting gas pressure in the

2,e 5 top one of the barrels 20 causes actuator 46 to be moved either in a forward or rearward stroke depending upon the station to which chamber unit 26 is indexed. During the initial portion of the stroke, actuator 46 moves along one of the linear portions 48 to hold drum assembly 24 against rotary displacement while right-hand rammer unit 54 moves a cartridge case 36 and a projectile 42 respectively into the ones of the chambers 34 and troughs 38 which are positioned in the charging stations relative to the bottom one of the barrels 20. At the same time, finger portion 62 engagingly moves the projectile 42 in the bottom battery station forwardly into the breech of the bottom barrel 20. Also, as cartridge case 36 is moved into the chamber 34 in the charging station, the expended cartridge case 64 therein is pushed forwardly thereby into the communicating one of the ejection ports 22 to move the expended cartridge cases therein forwardly. Such forward movement is permitted because arm portion 78 of stop member 76 is held within the cooperating one of the grooves 74 by latch 90. However, when the expended cartridge case in rear portion 66 is moved forwardly, latch 90 is cammingly moved thereby to a release position, but through the sliding engagement of arm portion 78 with such expended cartridge case the arm portion is maintained in groove 74 until the front end of such expended cartridge case engages ramp 72. Whereby, such expended cartridge case is cammed away from engagement with arm portion 78, as best shown by Fig. 8, to permit such arm portion to be pivoted through the bias of spring 88 into position to engage the front end of the expended cartridge case 64 being moved into rear portion 66 and thereby correctly position the rammed cartridge case 36 in chamber unit 26.

When actuator 46 enters the semicircular portion 52 of cam track 44 at the end of the actuating stroke, drum assembly 24 is rotated in a clockwise direction to the following station whereby the cartridge case 36 previously rammed into chamber unit 26 is rotated in back of the projectile 42 moved into the breech of the bottom of the barrels 20 to form a complete round of ammunition which, when fired, produces a reaction similar to that produced by the firing of the top barrel already described.

From the foregoing, it is clearly apparent that there is herein, provided an improved firearm structure in which the pair of barrels, the drum assembly and the ramming mechanism are uniquely arranged to fire at a rapid rate rounds composed of separate cartridge cases and projectiles, and that by separating the cartridge cases and projectiles the mass of the drum assembly is considerably reduced, permitting a corresponding reduction in the mass of the actuator, as well as the rotary displacement required of the drum and in the linear displacement of the actuator because of the reduced diameter of the drum. Further, the operating cycle has been simplified by having the expended cartridge cases ejected from the gun by the cartridge cases moved into the drum assembly whereby the ramming of such cartridge cases need not be delayed until the expended cartridge cases have been extracted rearwardly and moved out of the way as with conventional revolver-type firearms. Therefore, because of the rejection in mass and displacement of the parts and the simplification of the operating cycle, the firing rate of a firearm incorporating subject invention is considerably increased.

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.