Cartridge feeding mechanism

April 8, 1958

R. M. LA RUE

2,829,562

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United States Patent Office _Patenled and 8 of each belt link. When the cartridges are large and the weight and length of the loaded belt is considerable, the necessity for the stiffening property of the right angle web ? becomes evident. While the T-shaped cross sectional configuration of the guide rail is most conservative of weight for a given strength, other factors may dictate different configurations. The end of the guide rail extends into the breech-block mechanism to carry the cartridges into position for engagement with the cartridge unloading and firing mechanism, not shown,

The belt links are preferably fabricated from metal stampings, of such common sheet metals as steel or aluminum. The main link body, shown in Figs. 2 arid 3, comprises an open-sided or sectionalized circular barrel 10 which partially encircles the cartridge at or near the longitudinal center of gravity of the cartridge. The opening in the side of the barrel measures, circumferentially, less than 180°, and the dimensions of the barrel are so chosen that the cartridge may be snapped laterally into arid firmly though yieldably held in the barrel. Alternatively, the cartridge may be pressed end-on into the barrel during loading of the belt links. A cam, not shown, is usually employed in normal gun operation to force the cartridge laterally downward and free of the barrel. The barrel has two spaced axially aligned annular beads 11 and 12 and a window 13 therebetween to loosely receive the hinge sleeve 14 attached to the next adjacent barrel in the series of links of the belt. That is, the end edges of the sleeve which may be slightly flanged as at 15 and 16, and the depth of the beads 11 and 12 are so chosen that the sleeve can move, without binding, between the inside of the barrel and outer surface of the cartridge, much in the manner of an ordinary door hinge. When the cartridge, serving as the pin of the hinge is withdrawn, the otherwise securely interlocked sleeve and barrel fall apart. This link construction permits considerable flexibility of the loadirig belt, without sacrificing reliabihty, and adapts the belt to bending to fit small sized cowlings and turrets.

Flexibility of the belt in all directions is enhanced, further, by the specific barrel-to-sleeve attachment shown. The barrel and the sleeve are, in the illustrated embodiment, separate pieces of metal. A flat 17 is drawn on the side of the barrel, diametrically opposite the window 13, ^4a and is provided with an opening 18. The sleeve on the other hand is slit circumferentially inside the flanges 15 and 16 as shown. The tongue 19 thus formed is hooked at its end, and a complementary hook on the side edge of the sleeve is made. These two hooks, 20 and 21 Fig. 4, extend through and engage the opening 18. By keeping the tongue under tension, the hooks on the sleeve and the opening of the barrel are interlocked; yet the attachment is non-rigid and the belt has considerable freedom of gg bending movement in all directions.

The guide tabs 7 and 8 are preferably struck up. from the sheet metal of the top side of the sleeve portion of the cartridge link. Conveniently, the sheet is figure-8 pierced and post-formed to draw or knock out the lips or tabs. The spacing between opposed edges of the guide ^bu tabs, the distance between the tabs and the top surface of the sleeve, and the amount of overhang of the tabs are so chosen with respect to the dimensions of the specified guide rail as to assure free sliding movement of the guide tab along the guide rail without danger of detachment.

It is important that the cartridges be accurately aligned in the loaded belt. If a cartridge is displaced lengthwise with respect to its desired position in the belt, the unloading mechanism of the gun will fail, and the gun will jam. Conveniently, a locating skirt 22 is stamped integrally ⁷⁰ with the barrel portion of the link. The skirt may have the same general dimensions as the barrel to increase the gripping force on the cartridge, and may be of measured

2,829,562 CARTRIDGE FEEDING MECHANISM . o

Richard M. La Rue, Dahlgren, Va., assignor to the United States of America as represented by the Secretary of the Navy

Application February 3,1953, Serial No. 334,992 —

Claims. (CI. 89—33) (Granted under Title 35, U. S. Code (1952), sec. 266) . 15

The invention described herein may be manufactured and used by or for the Government ofthe United States of America for governmental purposes without the payment of any royalties thereon or therefor.

My invention relates to cartridge feeding mechanisms 20 for automatic fire arms and is particularly directed to cartridge belts and belt support mechanisms.

Canvas webbing for machine gun cartridges, which was found to wad and jam the gun, has long since been superseded by the metal link belt. The metal belt comprises, 25 usually, links of sheet metal stampings which are keyed together by the cartridges in such a manner that the links fall away from the gun as the cartridges are successively withdrawn. Unfortunately, links occasionally uncouple when the loading belt is kinked, necessitating 30 the addition of guide chutes to prevent kinking. Guide chutes, however, are expensive and are quite heavy by the weight standards demanded in ordnance generally and in airborne equipment in particular. Further, guide chutes could not be built to be readily adapted to the 35 close spaces in many gun turrets.

The object of my invention is an improved cartridge belt guide for automatic fire arms.

A more specific object of my invention is improved cartridge belts and guides which are light in weight, inexpensive to. manufacture, and can be adapted to small desired spaces without danger of decoupling the belt.

The objects of my invention are attained by an elongated feed rail, preferably being T-shaped in cross section with a web and flattened flanges of predetermined width, and a cartridge clip or link for yieldably engaging a cartridge, such links having two opposed overhanging guide tabe or extensions. The flattened portion of the rail interlocks and passes loosely under the overhang of said tabs so that the link may slide freely along the rail without disengaging the rail.

Other objects and features of my invention will become apparent from the description of one specific embodiment thereof in the following specification and shown in the accompanying drawings in which:

Fig. 1 shows the combination of my novel guide rail, cartridges, cartridge belt; and automatic fire arm,

Fig. 2 is a perspective detailed view of the guide rail, and cooperating link of my invention,

Fig. 3 is a detailed view of a belt link of my invention, and

Fig. 4 is a sectional view on line 4—4 of Fig. 3.

The automatic fire arm of Fig. 1 is shown with cartridges 1 in parallel alignment entering the breechblock mechanism 2 of the fire arm from right to left. The empty casings and belt links fall away on the left side of the breech-block. The cartridges and their belt links 3, Fig. 2, are supported throughout the length of the belt by the guide rail 4. The specific guide rail in the embodiment illustrated is essentially T-shaped in cross section, having a flattened flange or edge portion 5 upon which slides the integral guide tabs or ears 7

2,829,562

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length to longitudinally space the cartridge. One or more crimps 23 are pressed in the end edge of the skirt to yieldably engage the extractor groove of the shell casing. The skirt and· the barrel portions of the link, further, may be joined by a slightly raised bridge 24 under which a pointed cam of the gun mechanism, not shown, is inserted to force the cartridge laterally from the gripping sides of the barrel and skirt. Where light weight sheet metal is used, the usual stiffening bends may be formed in the stampings.

Good results have been obtained with link belts for cartridges of the 20 millimeter type, where cold rolled steel is used, about %2 inch thick and is blackened by a hard carbon or similar coating for corrosion resistance.

The cartridge belt and belt support mechanism of my invention obviates the cumbersome, heavy, expensive, and relatively rigid cartridge chutes heretofore commonly used in the art. My improved belt links will not uncouple even with severe kinking, are flexible, are light in weight, are inexpensive to manufacture, and are adapted to the close spacing of small turrets and cowlings.