US2792761A - Gun feeding mechanism - Google Patents

Description

y 21, 1957 c. E. SIMPSON GUN FEEDING MECHANISM 2 Sheets-Sheet 1 Filed Oct. 29, 1952 INVENTOR. Clarence E 5im :|sur1. BY v v v flrr'ozlvsrs' y 21, 1957 c. E. SIMPSON GUN FEEDING MECHANISM 2 Sheets-Sheet 2 Filed Oct. 29, 1952 INVENTOR. I: lure-nae E-51HLPE|DI1 n'rrozrvsns 2,792,761 Patented May 21, 1957 GUN FEEDKNG MEHANISM Clarence E. Simpson, Wilbraham, Mass assignor to the United States of America as represented by the Secretar-y of the; Army Application October 29, 1952, Serial No. 317,605

6 Ciairns. (Cl. Si -33) (Granted under Title 35', U. S. Code (1952), sec. 266) 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 cartridge feeding mechanisms for automatic firearms and is more particularly directed to improved means for transferring cartridges from a transversely fed linked belt to the firing chamber in the barrel.

One of the major problems resulting from the rapid rate of fire of automatic firearms is the obtaining of reliable feeding of the cartridges to the firing chamber from a continuous source of supply, such as a belt or magazine, so that jamming and misfire will not occur.

One means of feeding cartridges to an automatic firearm utilizes a disintegrating cartridge belt and a feedwheel to move the belt and cartridges therein to the feedway of the firearm. In such firearms, however, it is difiicult to deliver the cartridges to the feedway in direct alignment with the axis of the firing chamber inasmuch as the cartridge links of the belt and the sprocket portions of the feedwheel engaging the indexed cartridge would interfere with the weapons bolt in its reciprocal travel which must be in alignment with the axis of the firing chamber. Hence, the cartridges have to be removed from the belt and then moved angularly therefrom to the firing chamber which necessitates their undergoing a number of changes of direction and speed. For example, a cartridge is moved into the feedway by the feedwheel, stopped in index position, angularly inclined toward the firing chamber, picked up by the breech bolt traveling at a fast rate of speed, disengaged from the belt, moved angularly toward the chamber and after axial alignment therewith, thrust home.

Because of the rapid rate of fire of automatic firearms, these changes of direction and speed take place within a fraction of a second. Obviously, therefore, it is important that they be accomplished as smoothly and precisely as possible to prevent the cartridges getting out of control and jamming in the feed channel leading to the firing chamber. One of the critical moments in the feeding cycle occurs when the cartridge is being directed angularly from the belt to the firing chamber. The conventional means of deflecting the cartridge from the belt to the firing chamber comprises a rigid guide plate, adjacent the feedway, which engages the nose of the cartridge as it is being centered by the feedwheel. This engagement starts the depression of the cartridge which is further depressed while being thrust forwardly by the breech bolt. This arrangement, however, has the disadvantage that when the nose of the cartridge strikes the guide plate the impact is so great that the cartridge frequently gets out of control and becomes jammed in the feedway. Then, too, any oscillation of the belt during entry into the feedway affects the force with which the cartridges strike the guide plate and so varies their course to the firing chamber.

Accordingly, it is an object of this invention to prowheel and disintegrating cartridge belt, an improved feeding mechanism which is simple and rugged in construction and reliable in operation.

It is a specific object of this invention to provide a feeding mechanism for automatic firearms wherein the angular depression of the cartridge is effected by a movable depressor member which acts on counter-recoil after the cartridge has been fully indexed in the feedway during recoil thereby assuring that the cartridge is positively aligned with the firing chamber and that each cartridge is depressed with the same degree of force.

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. l is a fragmentary longitudinal sectional view of the feeding mechanism of this invention incorporated in a firearm and shows the depressor member directing the cartridge into the firing chamber;

Fig. 2 is a section on line 22 of Fig. 1

Fig. 3 is a bottom view of the cam slot in the driving member of the feeding mechanism;

Fig. 4 is a fragmentary sectional bottom view of the feedwheel showing parts of the clutch mechanism therein;

Fig. 5 is a fragmentary top View of the receiver with the cover removed; and

Fig. 6 is a perspective view of the cartridge depressor member.

Referring to the drawings, there is shown in Fig. 1 a firearm having a tubular-like receiver 12 with a hollow cylindrical sleeve 13 secured within the forward end thereof, and a barrel 14 removably mounted to the sleeve. Barrel 14 is provided with a conventional cartridge cham-. ber 15. A rectangular channel 9 is provided in sleeve 13 adjoining chamber 15 so as to be in axial alignment therewith, and is arranged to receive the forward end of a longitudinally reciprocating bolt 34.

In the upper portion of receiver 12, adjacent sleeve 13, there is provided a rectangular slideway 16 formed by side and end walls 17 and 18 respectively, which project integrally upward from receiver 12. Longitudinal grooves 19 extend along the interior surfaces of each wall 17 and are arranged to slidably engage mating longitudinal shoulders 20 along the sides of an actuating slide 21 provided on the rear end of a gas actuated operating rod. Fixedly mounted by any suitable means to the upper surface of slide 21 is a rectangular lug 22 disposed angularly to the longitudinal axis of slide 21 in a manner to be described later.

Rearwardly of slideway 16 there is provided in receiver 12 a feedway portion 8 wherein the front wall thereof is formed by wall 18 of slideway 16. Feedway 8 is also provided with a rear wall 24 and a longitudinal side Wall 25 which extends integrally upward from the right side of receiver 12. The top surface of Walls 24 and 25 of feedway 8 and walls 17 and 18 of slideway 16 lie in the same plane to form a seat for a cover 33. On the left side of feedway 8 is an arcuate ramp portion 26 which is slightly longer than a cartridge 27 and provides a passageway for entry of a cartridge belt. Said cartridge belt comprises a series of cartridge links, such as is shown by 29, connectedly hinged by cartridges 27; Directly opposite ramp 26, is an exit 28 in wall 25 of feedway 8 through which the empty cartridge links 29 are ejected after cartridges 27 have been stripped therefrom. The bottom of feedway 8 is concave as shown at 30 and connects ramp 26 with exit 28. In the central portion of fecdway 8 there is provided a longitudinal slot 31 which communicates with the interior of receiver 12, slot 31 having forwardly and outwardly, oppositely tapering sides Wide enough at the forwardmost end to permit one of cartridges 27 to pass therethrough.

Provided in the under side of receiver 12 below slot 31, is an ejection port 32 for the fired cartridge cases. On either side of port 32 within receiver 12, are a pair of longitudinal ribs 33 which slidably support bolt 34 and are therefore in axial alignment with the lower corners of rectangular channel 9. Bolt 34 is a substantially rectangular member having a spring-biased extractor 35 mounted in the bottom of the front end thereof and a resilient ejector 36 at the top thereof. A cartridge rammer 37 is integrally combined with ejector 36 and is normally biased upwardly intoslot 31.

Cover 38 is pivotally hinged to receiver 12 forward of slideway 16,'as shown at 81 in Fig. 1, and the underside thereof is arranged to mate with walls 17 and 18 of slideway 16, and walls 24 and 25 of feedway 8. Cover 38 is secured in closed position by a latch as shown at 39. Longitudinally mounted in cover 38 by means of suitable holes in either end wall thereof is a rod 42. The rear end of rod 42 is drilled out to receive a plunger 41 which is actuated by a suitable coil spring (not shown) to resiliently bias latch 39 downwardly. Rotatably mounted on rod 42 are a driving member 43, a co-acting clutch 44 and a sprocket feedwheel 45, one end of which 1is engageable with clutch 44 in a manner to be described ater.

Driving member 43 comprises a forwardly extending stern portion 46 and an enlarged head portion 47 at the rear end thereof. On stern portion 46 are a pair of protruding lips 48 which form therebetween a helical slot 49, best shown in Fig. 3, which receives lug 22 of actuating slide 21 when cover 38 is in closed position. The angle of lug 22 conforms to the helix angle of slot 49 so that it readily slides therein. The helix angle and length of slot 49 is such that when lug 22 is moved by actuating slide 21 of the operating rod from the foremost to the rearmost end of slot 49, driving member 43 is rotated of a turn in a counterclockwise direction, as shown in Fig. 2. Provided in stem 46, adjacent head 47, is an elongated recess 52 which is longitudinally aligned with the forward end of slot 49.

Mounted on drivingmember 43 is a cartridge depressor member 54 having a collar portion 53 which surrounds head 47 contiguous the rear surface of an annular flange 51 provided thereon. A depressor portion 55 is fixedly secured to collar 53 and extends forwardly therefrom. Said depressor 55 terminates at the forward end thereof in a finger portion 60 which projects upwardly into recess 52 and thereby secures cartridge depressor member 54 against rotation relative to driving member 43 and in line with the forward end of slot 49. The underside of depressor 55 slopes forwardly and downwardly and comprises a pair of longitudinally adjacent, planar surfaces 58 and 59 inclined, relative one to the other, at an obtuse angle. The planar surface adjacent wall 25, hereinafter referred to as directing surface 58, acts to direct the cartridges 27 from feedway 8 to chamber 15 as they are being propelled forwardly by bolt 34. When lug 22 of actuating slide 21 is in its normal forward position in slot 49, driving member 43 is positioned so that depressor portion 55 is centered in feedway 8 over slot 31 and directing surface 58 is perpendicular to the plane formed by the longitudinal axes of rod 42 and barrel 14. The second planar surface 59, hereinafter referred to as camming surface 59, acts as a means for camming cartridges 27 into position to be engaged by directing surface 58 during the rotation imparted to driving member 43 during the counter-recoil of slide 21.

Rcarwardly adjacent head 47 of driving member 43 is feedwheel 45 by which the cartridge belt is drawn into feedway 8. In the forward portion of feedwheel 45 there is provided an axial cylindrical cavity 64 arranged to re ceive a reduced diametral portion 57 of clutch 44 and a coil spring 63. Said coil spring 63 biases clutch 44 resiliently against driving member 43 so that a plurality of equally spaced ratchet teeth 61 on the rearward face of driving member. 43 engage mating ratchet teeth 62 on the forward face of clutch 44. Oppositely disposed, radially projecting keys 65 on the forward end of clutch 44, are slidably received by elongated keyways 66 in the forward end of feedwheel 45 so as to secure the clutch to the feedwheel and also allow it to be forced rearwardly in the feedwheel by driving member 43, as will be explained later.

Adjacent each end of feedwheel 45 are sprocket wheels 67 having a plurality of radial arms 68 spaced by arcuate recesses 69 shaped to fit around the case of cartridge 27. The ends of arms 68 terminate at the radial center of the case of cartridges 27 so as to equalize their contact on the circumference, of the cartridge case as it is being drawn thereby into feedway 8. This aids in reducing any unbalanced contact on cartridge 27 which might cause it to buckle and jam while being fed. Sprocket wheels 67 and ratchet teeth 61 and 62 on driving member 43 and clutch 44, respectively, are so arranged that when driving member 43 is in the position occupied when actuating slide 21 is in battery position, and, when ratchet teeth 61 and 62 are in full engagement, the longitudinal axis of the arcuate recess 69 indexed in feedway 8 is in line with the longitudinal axis of depressor portion 55 of cartridge depressor member 54.

Encircling feedwheel 45 between sprocket wheels 67 are a plurality of ratchet teeth 70 and annular bearing surfaces 71 on either side thereof. Extending transversely of feedwheel 45 and adjacent ratchet teeth 70, is a leaf spring 72 having a planar portion 73, which abuts upwardly against shoulders 74 provided in either side of cover 38. Projecting downwardly from one end of portion 73 is an arcuate portion 75, which encircles that portion of the ratchet teeth which lie adjacent exit 28 in receiver 12. Projecting from the opposite end of portion 73 is an arm member 76 that projects downwardly to engage ratchet teeth 70 and acts as a resilient stop for preventing counter-rotation of feedwheel 45.

A longitudinal slot 77 is provided in planar portion 73 to receive ratchet teeth 70, permitting planar portion 73 to press resil-iently against bearing surfaces 71 of feedwheel 45 and thereby hold planar portion 73 firmly against shoulders 74 and secure spring 72 to cover 38.

As has been explained, when cover 38 is closed and secured to receiver .12 by latch 39, rectangular lug 22 on actuating slide 21 is received by helical slot 49 in driving member 43. During the reciprocal travel of actuating slide 21, lug 22 moves from one end of helical slot 49 to the other producing an oscillating rotation of driving member 43. When actuating slide 21 is moved rearwardly during recoil, the rotation given driving member 43 is transmitted to clutch 44by engagement of the mating ratchet teeth 61 and 62 on the. driving member and clutch, respectively. This rotation is in turn transmitted to feedwheel 45 by keys 65 on clutch 44 which engage keyways 66 on feedwheel 45.

The return of actuating slide 21 to its normal forward position by suitable spring means 5(not shown), rotates driving member 43 in the opposite direction. Feedwheel 45 will remain stationary, however, as it is held against counter-rotation by arm 76 of leaf spring 72 engaging the suitably positioned ratchet teeth 70 on the feedwheel. The counter-rotation of driving member 43 is possible, while feedwheel 45 is locked, because the angular sides of ratchet teeth 61 and .62 cam clutch 44 resiliently into feedwheel 45 with keys 65 reciprocably sliding in keyways 66 thus allowing driving member 43 to move independently. At the end of the return stroke of actuating slide 21,.ratchet teeth 62 pass over the :apexes of ratchet teeth 61 allowing clutch 44 to move resiliently 55 at the same time is vertically centered above slot 31 positioning cartridge 27 vangularly' downward in the direction of channel 9 in sleeve 13.

To fire the weapon, the trigger mechanism (not shown) is actuated to release bolt 34. When bolt 34 is released, it moves forwardly on ribs 33 under propulsion of suitable spring means (not shown). As bolt 34 passes under slot 31, rammer 37 projects progressively upward therethrough to contact the base of cartridge 27 and push it through cartridge link 29 which is open at the bottom to permit unobstructed passage of rammer 37 therethrough. Cartridge link 29 is held in feedwheel 45 while cartridge 27 is being stripped therefrom by mechanism more fully described and explained in U. S. Patent No. 2,648,258. While cartridge 27 is being pushed forwardly by rammer 37 it moves forwardly in contact with directing surface 58 of cartridge depressor 55 and down through slot 31. The tapering sides of slot 31 and arms 68 of feedwheel 45 assist in keeping cartridge 27 directed toward channel 9 of sleeve 13. As cartridge 27 is moved forwardly, it progressively enters channel 9 of sleeve 13 until aligned therewith and its base is in full contact with the forward face of bolt 34 which forces the cartridge into firing chamber 15 and fires it by conventional means.

The gases created by the firing of cartridge 27 are bled from barrel 14 into a cylinder (not shown) to force the operating rod and the attached actuating slide 21 rearwardly. As has been previously explained, the rearward travel of actuating slide 21 rotates driving member 43 to move cartridge depressor 54 out of the way of the incoming cartridge 27 as feedwheel 45 is also being rotated to index such cartridge in feedway 8. As cartridge 27 is being drawn into feedway '8 by feedwheel 45, cartridge link 29, freed during the previous cycle of fire, is ejected thereby out of exit 28. Arcuate portion 75 of leaf spring 72 assures a smooth ejection of cartridge link 29 and thereby prevents the possibility of jamming between feedwheel 45 and cover '38. The rearward stroke of actuating slide 21 also unlocks bolt 34 and propels it rearwardly with extractor 35 withdrawing the fired cartridge case. When actuating slide 21 reaches the limit of its rearward travel, it is immediately returned to its normal forward position by suitable spring means while bolt 34 continues rearwardly in receiver 12 to eject the empty cartridge case out of ejection port 32 and be either engaged by suitable trigger mechanism or allowed to return and fire another round. In the meantime, the return stroke of actuating slide 21 counter-rotates driving member 43 to return cartridge depressor 54 to its normal position. During this counter-rotation of cartridge depressor 54, cam surface 59 thereof depresses cartridge 27 which is held by feedwheel 45 until surface 58 moves onto cartridge 27 which is thereupon ready to be picked up by bolt 34.

it can readily be seen that inasmuch as the cartridge is depressed after being aligned with the axis of the firing chamber and while it is firmly secured in the feedwheel, and at rest, the likelihood of the cartridge jamming during feeding has been considerably reduced. It is also obvious that there is here provided a feeding mechanism which is compact, simple, and rugged in construction.

I claim:

1. In a firearm having a longitudinally reciprocal bolt, a barrel, and a firing chamber in the barrel, the combination of a transverse feedway located in a higher plane than the bolt and barrel, said feedway having a longitudinal cartridge slot centrally thereof, a feedwheel rotatably mounted above said slot, means for intermittently rotating said feedwheel to advance a linked belt of cartridges along said feedway for positioning the leading cartridge in parallel alignment with said slot, a rotatable cartridge depressor having a depending portion projecting into said feedway and normally positioned in parallel alignment with said slot, means associated with said feedwheel for rotating said ca tridge depress-or to move said depending portion out of the path of the leading cartridge during the feeding movement thereof and for returning said depressor to the nonrotated position thereof subsequent to the feeding movement of the leading cartridge but prior to the forward movement imparted thereto by the bolt, first cam means along the side of said depending portion for inclining the leading cartridge downwardly toward alignment with the firing chamber during the return of said depressor to the non-rotated position thereof, and second cam means on the underside of said depending portion for progressively guiding the leading cartridge into the firing chamber during the delinking and chambering movements thereof.

2. In a firearm having a receiver, a bolt slidably mounted in the receiver for longitudinal reciprocal movement, a barrel, and a firing chamber in the barrel, the combin'a tion of a cover hingedly secured at the forward end thereof to the receiver, the underside of said cover and the top of the receiver cooperating to define a transverse feedway in a higher plane than the bolt and barrel, said feedway having a longitudinal cartridge sl-ot centrally thereof, a feedwheel rotatably mounted in said cover above said slot, means for intermittently rotating said feedwheel to advance a linked belt of cartridges along said feedway for positioning the leading cartridge in parallel alignment with said slot, a cartridge depressor rotatably mounted forwardly of said feedwheel and having a depending portion inclined forwardly and downwardly to normally proje'ct vertically into said feedway in parallel alignment with said slot, means associated with said feedwheel for rotating said cartridge depressor to move said depending portion out of the path of the leading cartridge during the feeding movement thereof, means for preventing the rotation of said feedwheel during the return of said depressor to the nonrotated position thereof and prior to the forward movement imparted to the leading cartridge by the bolt, first carn means along the side of said depending portion of said depressor for inclining the leading cartridge downwardly toward alignment with the firing chamberduring the return of said depressor to the non-rotated position thereof, and second cam means on the underside of said depending portion of said cartridge depressor for progressively increasing the inclination imparted to the leading cartridge by said first cam means, said second cam means being arranged to cooperate with said slot in said feedway for guiding the leading cartridge out of the link engaged therewith and into the firing chamber of the barrel.

3. In a firearm having a longitudinally reciprocal bolt, a firing chamber in axial alignment with the bolt, and means for intermittently feeding a belt of linked cartridges transversely into the firearm above the bolt and parallel to the longitudinal axis thereof, the combination of a cartridge depressor rotatably mounted in the firearm above and to the rear of the firing chamber to normally depend into the feeding path of the leading cartridge, a first cam surface disposed along the side of said cartridge depressor nearest the leading cartridge, means for rotating said cartridge depressor in one direction to swing said first cam surface out of the path of the leading cartridge during the feeding movement of the belt and for rotating said cartridge depressor in the opposite direction during the interval between the intermittent feeding movements of the belt but prior to the chambering movement of the leading cartridge whereby said first cam surface tilts the front end of the leading cartridge downwardly into alignment with the rear end of the firing chamber, and a second cam surface on the underside of said cartridge depressor for guiding the tilted cartridge into the firing chamber during the chambering movement imparted thereto by the bolt.

4. In a firearm having a concave transverse feedway, a bolt slidably disposed below the feedway for longitudinal reciprocal movement, and a firing chamber in axial alignment with the bolt, cartridge feed means comprising a feedwheel rotatably mounted above the feedway, a driving member rotatable in either direction, clutch means interposed between said driving member and said feedwheel for limiting rotation of the latter in the feeding direction only, a cartridge depressor fixedly secured to said driving member to normally depend into the feeding path of the leading cartridge, 21 forwardly and downwardly inclined first cam surface disposed along the side of said depressor nearest the leading cartridge, means for rotating said driving member in either direction whereby counterclockwise movement thereof actuates said feedwheel to advance the cartridge belt along the feedway and simultaneously swing said depressor out of the feeding path of the leading cartridge and clockwise movement of said driving member returns said cartridge depressor to the normal depending position thereof whereupon said first cam surface contacts the leading cartridge to tilt the front end thereof downwardly into alignment with the rear end of the chamber, and a forwardly and downwardly inclined second cam surface on the underside of said cartridge depressor for guiding the tilted cartridge into the firing chamber during the forward movement imparted thereto by the bolt.

5. In a firearm having a receiver, a bolt slidably mounted in the receiver for longitudinal recoil and counterrecoil movement, and a firing chamber in axial alignment with the bolt, the combination of a concave feedway formed transversely across the receiver above the bolt, said feedway having a centrally disposed, forwardly diverging 1ongitudinal slot, a cover hingedly secured to the forward end of the receiver, a longitudinal rod rotatably mounted in either end of said cover, a feedwheel fixedly mounted on said rod, sprocket means on said feedwheel for engaging a belt of linked cartridges disposed on said feedway when said cover is closed, a driving member fixedly mounted on said rod forwardly of said feedwheel, means for rotating said driving member in either direction during recoil of the bolt, clutch means interposed between said driving member and said feedwheel for limiting rotation of thelatter to the direction in which said sprocket means advances the cartridge belt along said feedway, and

a cartridge depressor normally disposed above said slot in said feedway and in the feeding path of the leading cartridge in the belt, said depressor having a forwardly and downwardly inclined surface on the underside thereof and a cam surface extending longitudinally along the side thereof and inclined upwardly and outwardly at an obtuse angle relative to said inclined underside surface, means for mounting'said depressor on said rotatable driving member to swing out of the path of the leading cartridge in the belt during the feeding rotation imparted to said feedwheel and to swing into contact with the leading cartridge during rotation of said driving member in the opposite direction, said longitudinal cam surface being disposedso as to cam the leading cartridge therebeneath and to simultaneously tilt the front end thereof downwardly into alignment with the rear end of the firing chamber, the inclination of the underside of said depressor being arranged to cooperate with the diverging slot in the feedway to guide the tilted cartridge into the firing chamber during the forward movement imparted thereto by the counterrecoiling bolt.

6. The combination defined in claim 5 wherein said means for mounting said depressor on said driving member comprises a collar portion extending upwardly from the rear end of said depressor, and a lug projecting upwardly from the front end of said depressor, said driving member having a longitudinal slot in the underside thereof for receiving said depressor lug, said slot being of greater length than said depressor lug to permit said collar portion to slide onto the rear end of said driving member.

References Cited in the file of this patent UNITED STATES PATENTS 1,446,388 Ludorf Feb. 2-0, 1923 2,113,202 Stange Apr. 5, 1938 2,453,786 Dixon Nov. 16, 1948 2,454,251 Hamilton Nov. 16, 194? FOREIGN PATENTS 67,215 Denmark July 12, 1948

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