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Publication numberUS3181423 A
Publication typeGrant
Publication dateMay 4, 1965
Filing dateFeb 17, 1961
Priority dateFeb 17, 1961
Publication numberUS 3181423 A, US 3181423A, US-A-3181423, US3181423 A, US3181423A
InventorsRocha John G
Original AssigneeRocha John G
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Motor driven automatic gun
US 3181423 A
Abstract  available in
Images(5)
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Claims  available in
Description  (OCR text may contain errors)

My 4, 1965 J. G. ROCHA 3,181,423

MOTOR DRIVEN AUTOMATIC GUN Filed Feb. 1'7. 1961 5 Sheets--SheerI 2 26 E Cp- IN V EN TOR.

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Magd/gi May 4, 1965 J. G. ROCHA MOTOR DRIVEN AUTOMATIC GUN 5 Sheets-Sheet 3 Filed Feb. 1v, 1961 1N VEN TOR. .In-hn [EL-Rn c1111 ,Pozza sf QJQM May 4, 1965 J. G. ROCHA MOTOR DRIVEN AUTOMATIC GUN 5 Sheets-Sheet 4 Filed Feb. 17. 1961 phnl mm m u m mR 1 JM um; w? mm Jj @moa van. QM

May 4, 1965 J. G. ROCHA 3,181,423

MOTOR DRIVEN AUTOMATIC GUN Filed Feb. 1'?. 1961 5 Sheets-Sheet 5 INVENTOR.

Y have :not been entirely successful.

United States Patent C) M 3,181,423 M'IR DRIWEN AU'IGMATIC GUN John G. Rocha, Westfield, Mass., assigner to the United States of America as represented by the Secretary of the Army Filed Feb. 17, wel, Ser. No. 90,147 7 Claims. (Cl. t39-l6l) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Goverment for governmental purposes Without the payment of any royalty thereon.

This invention relates to automatic machine guns of the type wherein the barrel moves forwardly out of battery position upon the firing of each round and is more particularly directed to means for operating a -gun of thisitype through an external source of power. Y

In automatic machine guns of the type whereinV the actuating parts are energized in direct response to the forces generated by the discharge off the `amn'iunition therefor, the rate of fire is generally fixed due to the difliculties involved in varying the accelerations and speeds ot' the moving pants. However, present day military requirements demand considerable flexibility in the rate of fire in order to permit equally satisfactory operation for ground use or in vehicles, such 'as aircraft or tanks, both Vduring attack or defense against a variety of targets.

Previous attempts to provide a variable rate of fire, which would permit the operator of the gun to select the particular rate bestsuited to the tactical use then required, For example, the use of hydraulic buffer mechanisms for decreasing the rate of re requires `additional space for the storage of special uids while the use of mechanical or spring devices for temporarily interrupting the travel of the recoiling parts introduces relatively ,complex Iassemblies easily susceptible to malfunction. l

lthas, therefore, been proposed that the gun be continuously driven by an external source `of power, such as an electric motor having a variable output. However, the use of -this source Vof energy has heretofore been limited to Weapons with revolving chambers or a rotating cluster of barrels.

Accordingly, it is a broad object of this invention to ,Y utilize an external source of electrical energy for operatbarrel is adapted to be moved rearwardly into battery positiomand-the pivotal hammer employed to energize a longitudinal striker is arranged to be cocked by the rearward movement of the barrelinto lockedbattery position thereby preventing thepossibility of firing in the event the barrel fails to function properly.

Still another object of this invention lis the provision ,of an automatic gun of the aforesaid type wherein the locking `of the ybarrel in battery position ,and vthe release of the cocked hammer effected in sequence by the same cam track in a rotatable operating drum thereby assuring the completion of locking prior to the vinitiation of firing.

An additional object of this invention lies inthe provision of an .automatic gun of the aforesaid Vtype wherein the cycling of the reciprocal barrel is not dependent upon the ring of `a round therein so that a failure to feed will not interrupt the continuity of automatic fire.

A specificV object of this inventionis the provision of an extremely compact and reliable gunof the aforesaid 3,181,423 retainedv May 4, rees ICC FIG. 2 is an enlarged elevationalcross-section of the rear portion of the gun showing the barrel in battery position immediately prior to locking thereof and also show ing the hammer in the cocked position;

FIG. 3 is a view similar to that of FIG. 2 but showing the parts in 4the position assumed at the instant of ring;

FIG. 4 is an enlarged cross-section taken along lines 4 4 in FIG. 1 to show the conguration of the locking cam inthe operating drum;

FIG. 5 is a cross-sectional View taken along line 5 5 in FIG. 1 through the hammer cooking plunger and the hammer Sear;

FIG. 6.is la cross-sectional view taken along line 6-6 Y in FIG.v 1 to show the structural details of the hammer and scar mechanisms as seen from the rear;v

FIG. 7 is a cross-sectional View taken along line 7-7 in FIG. 2 to show the details of the sear release mechanism in the cocked position of the hammer;

FIG. 8 is a cross-sectional view taken along line @-8 in FIG. 2 to show further details of the sear'release mechanism;

FIG. 9 is a cross-sectional view taken along line 9--9 in FIG. 3 in a manner similar to that of FIG. 7 but with the hammer and sear mechanisms shown in the tiring positions thereof;

FIG. 10 is a cross-sectional view taken along line tti-ttl in FIG. 3 in a manner similar to that of FIG. 8 but with the hammer and sear mechanisms shown in the lining positions thereof; and

FIG. ll is an enlarged exploded perspective view of the entire firing mechanism.

As illustrated in the drawings, the gun of the present invention includes a substantially rectangular receiver l2 having ra bifurcated extension 14 projecting from the rear end thereof for straddling a housing l5 which is releasably secured thereto -for containing a firing mechanism as will be hereinafter described. Receiver 12 is also provided with a forwardly opening bore i6 for slidabiy receiving a barrel 1S. Rotation of barrel t8 in reiver 12 Y `-gun to any suitably fixed bracket kor hanger 26 in which the required mating slots 23 are formed. Receiver 12 is open along the underside thereof, :as `best shown at Sti, andV is provided with depending front and rear drum supports 32 and 3d respectively secured thereto on either vside, of opening 3h.

`Supports 32 and 34 are joined by'a rotatable shaft-36 on which is centrally mounted a hollow cylindrical oper- `atingdrum 38. An electric motor 4d having a variable ,output is secured to rear drum support 32 so that the projecting spindle 42 on motor eti engages in the rear end of shaft 36 to impart clockwise rotation to drum 33, If necessary, motor 4t) may be replaced by a suitable cranking device whichwill permit manual rotation of drum 33. The exterior periphery of drum 3S is formed with a continuous cam track 44 of suicient width to receive the enlarged head of a follower 46 protruding from the underside of key portion on barrel 18. Cam track 44 is generally helical in configuration, but includes a straight dwell portion for a purpose to be hereinafter explained. Thus, the rotation of motor 40 imparts longitudinal reciprocation to barrel 18 away from and toward battery position in receiver 12.

A pair of bearing rings or collars 48 are preferably integral with the exterior of barrel 18 and are sufliciently spaced apart to ensure that in any position of barrel 18 the exterior periphery of at least one collar will remain in contact with the interior surface of receiver bore 16. This construction allows barrel 18 to distort slightly during the longitudinal travel thereof without binding in receiver bore 16. However, at the instant of ring a round in barrel 18, both collars 48 are in contact with the interior periphery of bore 16 toinsure maximum accuracy in the Hight of the projectile.

A barrel lock 50 is slidably disposed in the upper end of d rear drum support 34 and is arranged to pass through a suitable slot 52 in the underside of receiver 12 and engage in a locking recess 54 formed in the underside of barrel 18. Barrel lock S0 is actuated into and out of locking position through the camming engagement between a cam follower 56 thereon and a cam track 60 formed into the rear face of drum 38. Cam follower 56 is xedly secured in barrel lock 50 and projects forwardly therefrom through a vertically elongated opening 58 in rear drum support 34. As best shown in FIG. 4, cam track 60 is circular in configuration except for an angular locking portion 62 and an oppositely inclined unlocking portion 64. Cam portions 62 and 64 are sufficiently spaced apart to form a dwell portion 66 for a purpose to be shown. The width of dwell portion 66 is slightly less than the corresponding width of dwell portion 45 in barrel cam track 44 in order to ensure continuous positive control of barrel lock 50 in the locking position thereof despite any adverse accumulation of tolerances.

Immediately above cam follower 56, barrel lock 50 is provided with a vertically disposed inverted T-slot 74 having inclined grooves 76 formed into the opposite sidewalls thereof. The rear end of follower 56 is notched, as indicated at 78, at the angle which will prevent any blocking of grooves 76. A Sear release plunger 80 is longitudinally disposed for slidable reciprocal movement in the upper portion of rear drum support 34 and is provided with a substantially rectangular forward end 82 having a portion thereof sufficiently reduced in thickness along an inclined path coextensive with grooves 76 in barrel lock 50 to form opposing shoulders 84 for mating engagement therewith. The rear end of plunger 80 is arranged to project from the rear of drum support 34 into the hollow interior of housing 15 and is provided with a rectangular portion 86 terminating in an enlarged head 88 having a beveled side face, as best illustrated at 90 in FIG. ll, for a purpose to be hereinafter explained. Rectangular portion 86 of sear release plunger 80 containsa longitudinally elongated slot 92 for the passage therethrough of a transverse pin 94 on which a sear carrier 96 and a hammer 98 are pivotally mounted.

Sear carrier 96 is provided with a pair of spaced apart mounting lugs 100 on the underside thereof which straddle the rear end of sear release plunger 80 and are suitably bored, as indicated at 102, to align with elongated slot 92 for the passage of mounting pin 94 therethrough. A torsion spring 104 is arranged to surround the outer end of transverse pin 94 and lie between the outer mounting lug 100 and the rear end of sear release plunger 80. One end of spring 104 bears against the underside of sear carrier 96 while the other end bears against the floor surface in housing 15 thereby normally urging sear carrier 96 in a clockwise direction. The body of sear carrier 96 is centrally drilled into one end thereof, as indicated at 105 in FIG. 5, to provide a seat for a cylindrical sear 106 having a hollow interior arranged to house a spring 108. In addition, Sear carrier 96 is notched, as best shown at 110 in FIG. ll, to provide a passage therethrough for the longitudinal travel of plunger head 88 and is slotted, as illustrated at 112, along an axis parallel to the centrally drilled hole 105 therein and in communication therewith.

Rotation of sear 106 in carrier 96 is prevented by a relatively narrow bar 114 integral with otherwise secured to the underside of the sear, as best shown in FIG. 1l, and engageable in sear carrier slot 112. When scar 106 is properly assembled in carrier 96, spring 108 urges the opposite end of sear 106 into engagement with a horizontally elongated opening 116 formed into the side of hammer 9S. One end of sear bar 114 extends slightly beyond the corresponding end of sear 106 while the opposite end of bar 114 stops short of the other end of sear 106 to terminate in a laterally inclined cam surface 118. When Sear 106 is in engagement with hammer 98, cam surface 118 on bar 114 lies in the path of the beveled side face 90 of head 88 on Sear release plunger 80.

Hammer 98 is pivotally mounted at the lower end thereof on transverse pin 94 and is provided with a solid head 120 adapted to strike the projecting rear end of a firing pin 122 slidably mounted in the rear end wall of receiver 12. This ring movement of hammer 98 is obtained through the medium of a spring-biased plunger 124 slidably seated within an inclined well 123 formed into the back wall of receiver extension 14 and bearing against an arcuately formed surface 128 on the rear of hammer 98. The forward end of hammer plunger 124 is provided with an extension 125 terminating in a surface 126 substantially parallel to the rear face of receiver 12. The upper and lower surfaces of plunger extension 125 are grooved, as shown at 127, for engagement by mating rails 129 formed along the opposite walls of a T-slot 130 provided in the side wall of housing 15. Contact of hammer plunger extension 125 with the rear end of receiver 12 immediately prior to the impact of hammer head 120 with firing pin 122 halts travel of hammer plunger 124 for a purpose to be shown.

Firing pin 122 is slidably mounted in a plug 131 threaded into a suitable counterbored opening 132 in the back wall of receiver 12. Plug 131 is itself provided with a counterbore 134 to receive an annular flange 136 on firing pin 122 which serves as a backstop for the rear end of a spring 138 disposed within the smaller diameter portion of counterbore 134. Thus, firing pin 122 is normally urged rearwardly away from the base of a cartridge 140 chambered in the rear end of receiver bore 16 and held therein by arcuate ribs 142 projecting in front of the conventional cartridge case rim 144.

A hammer cooking plunger 146 is slidably disposed in a longitudinal hole 148 extending through the back wall of receiver 12. The forward end of plunger 146 projects suiciently into receiver bore 16 to be contacted by the rear end of key portion 20 during rearward movement of barrel 18 into battery position. The rear end of plunger 146 is arranged to contact a slabbed surface 150 formed on the front of sear carrier 96. Thus, plunger 146 serves to convert the rearward thrust of barrel 18 into pivotal movement of sear carrier 96 which in turn moves sear 106 to cock hammer 98. The entire firing mechanism herein described in inclosed in a cover 152 fastened about housing 15.

When electric motor 40 is turned on to initiate rotation of drum 38, the engagement of cam follower 46 in helical cam track 44 will cause barrel 18 to move in the same direction and from the same location as that reached at the time motor 40 stopped during the previous cycling of the gun. If the parts are in the position of FIG. l, barrel 18 will begin to move rearwardly over the chambered cartridge 140 which was previously fed into engagement with receiver ribs 142 by suitable feed mechanism (not shown). As barrel 1S approaches the battery position shown in FIG. 2, key portion 20 thereon will force hammer cooking plunger 146 to rotate s ear carrier 96 in a counterclockwise direction about pin 94. movement of sear `carrier 96 is imparted to hammer 98 through the engagement ofthe latter by sear 106 under the urgingof spring 108. As shown in FIG. 2, hammer 98 is fully cocked when barrel 18 reaches battery position and cam follower. 46 thereon enters the dwell or straight portion 45 in cam track 44 on the exteriorof drum '38.

Cam track 60 is so located, in the rear face of drum 38 that cam follower 56 on barrel lock Si) will be contacted by the locking cam portion 62 to lift barrel lock 50 into Vlocking recess 54 at the moment the rearward movement of barrel 18 has terminated. As barrel lock S0 is lifted, inclined grooves 76 therein cam sear release plunger Si) rearwardly. During this movement, the beveled side face of plunger 80 rides along the inclined end of sear bar 114 and cams the projectingend of sear 106 into sear carrier 96 and out of engagement 'with hammer 98. The Vsubse-l quent firing movement of the hammer 98 is obtained through the bias of hammer plunger 124 which was -initially compressed during the cocking of hammer 98. The rearward movement of sear release plunger 80 is terminated upon contact of the forward end of elongated slot 92A therein with transverse pin 94. Y

The forward movement imparted to firing pin 122 by hammer 98 res the chambered cartridge 140. Dwell portion 45 of cam track 44 is arranged to provide a barrel locking interval of sufficient length to ensure the dissipation of the residual gas Vpressure in receiver bore 16. Thereupon, cam follower 56 is contacted by the unlocking cam portion 64 of cam track 60 to withdraw barrel lock 50 from engagement with barrel 18. At this moment, the cam portion of cam track 44 begins to move barrel 18 forwardly to permit feeding of the next cartridge 14) into chambering position in receiver 12.

Since the forward travel of hammer plunger 124 is halted by rear end of receiver 1,2 immediately prior to the completion of travel Vby hammer 98, the absence of any load thereon in the position shown in FIG. 3 permits liring pin spring 138 to force tiring pin 122 rearwardly against the weight of hammer head 120 to the extent required to retract the tip thereof out of the path of the incoming cartridge 140.

The aforesaid cycle of operation is repeated as long as motor 40 operates to rotate drum 38 andsince the barrel is mechanically actuated, any failure to feed or ignite a cartridge will merely interrupt rather than halt continuous automatic tire. Moreover,'since locking of the barrel in battery position must precede the vcocking of the hammer, accidental or premature tiring of a cartridge is positively prohibited.

In addition, the manner in which the motor-driven operating drum is combined with a longitudinally reciprocal barrel adapted to move forwardly out of battery position upon the firing of a cartridge reduces the space required rearwardly of the breech and thereby creates an extremely compact gun which can be operated'in any desired position in which fixed mounting of the receiver can be effected.

. The greatest benet produced byrthe aforesaid novel combination of parts lies in the ease with which the rate of fire can be varied from one extreme to the other and thereafter maintainedin any rate selected by the operator.

Although a particular embodiment of the invention has been described in detail herein, itis evident thatfmany variations may befdevised within the spirit and scope thereof and the following claims are intended to include such variations.V

I claim: Y

1. In an automatic gun having a receiver with a longitudinal bore formed into one end thereof for holding a cartridge in firing position, and a barrel slidablydisposed in the bore for reciprocable movement to and from battery position, the improvement of an operating drum rotat- This pivotal '6 ably secured l to the receiver, a cam "follower projecting from the barrel, cam track means in said drum engageable Ywith said follower for continuously cyclingV the barrel forwardly from battery position and rearwardly in return thereto, and means responsive to the rotation of said drum for firing the cartridge subsequent to movement of the barrel into battery position.

2. In an automatic gun having a receiver with a longitudinal forwardly opening bore adapted to successively retain cartridges therein in a firing position, a barrel slidably disposedin the bore for reciprocal movement into and out of battery position, an operating drum rotatably secured to the receiver, a cam follower projecting from said barrel, camV track means in the exterior periphery of said drum engageable with said follower for cycling Ysaid barrel'forwardly away from battery position and rearwardly for return thereto, a barrel lock slidably disposed in the receiver for reciprocal movement into and out of locking engagement with said barrel, cartridge firing means operable in response to the locking movement of said barrel lock, cam track means in the rear face of said drum for cycling said barrel lock in relation to the reciprocal movement of said barrel such that the latter is locked against forward movement out of battery position during the interval in which the cartridge is fired and the resulting discharge gases are reduced to safe limits.

3. The combination defined in claim 2 wherein the receiver is open along a portion of the underside of the bore therein and said barrel is surrounded by a pair of fixed bearing collars spaced apart to such an extent that at least one of said collars is in bearing contact with the interior bore surface in the receiver at any instant during the reciprocal travel of said barrel, both of said collars being in said bearing contact during the battery position of said barrel.

4, In an automatic gun having a receiver with a longitudinal forwardly opening bore adapted to successively retain cartridges therein in a tiring position, a barrel slidably disposed in the bore for reciprocal movement into and out of battery position, the receiver having an opening thereto provide access to the barrel, an operating drum rotatably secured to the receiver with the exterior periphery thereof adjacent said access opening therein, electric motor means secured to the receiver for rotating said drum, a first cam track formed into the exterior periphery of said drum and having a helical cam portion on both sides of a dwell portion, a cam follower projecting from said barrel through said access opening in the receiver and into engagement with said first cam track for cycling said barrel forwardly away from battery position and rearwardly for return thereto, a barrel lock slidably disposed in the receiver for reciprocal movement into and o ut of locking engagement with said barrel, a second cam trackV formed into the end face of said drum and having a dwell portion included between apair of camming portions, a cam follower projecting from said barrel lock into engagement with said second cam track, said first and second cam tracks having said camming and dwell portions thereof respectively located in said drum to provide alternate cycling of said barrel and said barrel lock whereby the former is locked against forward movement out of battery position until the cartridge has been red andthe residual gas pressure reduced to safe limits, and cartridge firing means operable by the locking movement of said barrel lock.

Y 5. The combination defined in claim 4 wherein said Vdwell portion in said barrel cam track is of slightly greater width than the remaining cam portion thereof to pernormally urging said hammer into striking contact with said firing pin, a sear engageable with said hammer, means responsive to the rearward movement of said barrel into battery position for forcing said sear to cock said hammer, and a plunger cammingly engageable with said barrel lock whereby the locking movement of the latter functions said plunger to withdraw said sear and release said hammer against vsaid firing pin.

7. The combination defined in claim 4 whereby said cartridge tiring means comprises a spring-biased ring pin slidably Seated in the rear end of the receiver and normally urged away from contact with the cartridge in the iring position thereof in the receiver, a spring-biased hammer pivotally mounted in the receiver for striking contact with said firing pin, a sear carrier pivotally mounted in the receiver jointly with said hammer, a springbiased sear normally urged into engagement with said hammer, a hammer cocking plunger slidably disposed in the receiver for contact with said sear carrier during the movement of said barrel into battery position whereby the resulting pivotal movement of said carrier is imparted through said sear to said hammer for the cocking thereof, and a sear release plunger slidably disposed in the receiver for camming said sear out of engagement with said hammer, said sear release plunger and said barrel lock having cooperating cam means for converting reciprocal Vertical movement of said lock into reciprocal longitudinal movement of said sear release UNITED STATES PATENTS 4/49 Corte 89-159 5/58 Lyon 89-161 X BENJAMIN A. BORCHELT, Primary Examiner.

SAMUEL BOYD, Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2466577 *Dec 6, 1944Apr 5, 1949Lockheed Aircraft CorpBolt mechanism for guns
US2835171 *Mar 14, 1952May 20, 1958Albert Lyon GeorgeRotary magazine gun
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3302524 *Oct 12, 1965Feb 7, 1967Jerome DejaCartridge stop means for externally powered automatic guns
US3327587 *Sep 7, 1965Jun 27, 1967Lizza Albert JRotary cam actuated operating rod mechanism
US3455204 *Sep 29, 1965Jul 15, 1969Stoner EugeneFeeding mechanism for an automatic gun
US4167888 *Nov 25, 1977Sep 18, 1979Etat Francais, as represented by Delegue General pour l'ArmementAutomatic firearms with external motor
US5392685 *Aug 18, 1983Feb 28, 1995Ares, Inc.Automatic cannon with carbioid-shaped shell chamber path
US5564964 *Aug 25, 1994Oct 15, 1996Chin-Chien; LinToy gun with helically driven reciprocating barrel
US7089844 *Aug 12, 2003Aug 15, 2006Krauss-Maffei Wegmann Gmbh & Co. KgDevice for electrically controlling an automatic weapon
US20050262992 *Aug 12, 2003Dec 1, 2005Wolfgang BeckerDevice for electrically controlling an automatic weapon
US20090064854 *Nov 27, 2005Mar 12, 2009Gadi MametCocking device for machine guns
Classifications
U.S. Classification89/161, 89/9
International ClassificationF41A7/00, F41A7/10
Cooperative ClassificationF41A7/10
European ClassificationF41A7/10