Patent GB-133329-A (GB)
Title: Improvements in Machine Guns.
Inventor: IMRAY OLIVER
IPC: F41A3/82
Filed: 1917-05-21
Abstract: 133,329. Imray, O., (Colt's Patent Fire Arms Manufacturing Co.). May 21, 1917 Machine guns.-Relates to recoil-operated machine guns of the kind described in Specification 14921/00, and consists mainly in arranging the barrel, the breech mechanism, and the guides therefor so that they can be removed as a whole through the vertically - sliding rear plate of the breech casing. As shown in Fig. III, the breech mechanism is arranged within a casing comprising two side plates a secured in front to a trunnion block D having a circular flange d, to which the rear end of the cooling-jacket b is attached. The rear part of the bottom of the casing is closed by a plate L, an open space being left in the front part for the discharge of the spent cartridge cases. Similarly, the top of the casing is covered by a plate H which leaves the front part open for the insertion of the cartridge belt; this front part is then closed by a. hinged cover G, which is locked in place by a sliding bolt I on the plate H. The rear end of the casing is closed by a sliding plate J inserted from the top, and locked in place by the bolt I. This bolt is normally held in place by a spring catch i, but it can be pushed back to release the hinged cover G and then pushed forward to release the back plate J after the hinged cover has been swung up. The gun barrel B is mounted within the cooling-jacket in the usual way and is screwed to a barrel extension C, the rear end of which has a downward projection guided by a seat ! on the base-plate L. The breech-bolt E slides on the barrel extension and on a guide-block F, which is held in place by the rear plate J. The side handle for working the breech mechanism by hand is guided by a slot in the side plate a and is held against removal by a flange on the handle bearing against the inner face of the plate a. When the rear plate J is removed, the breech-bolt can be moved farther back; this brings the flange of the handle opposite a widened part of the guide-slot, enabling the handle to be removed. The barrel, barrel extension, and breech mechanism can then be removed as a whole through the rear end of the casing. To permit the insertion and removal of the rear plate J, the guide-rod r of the recoil spring R is looked by a bayonet-joint into the corresponding recess in the breech-bolt when this is in its rearmost position; then; when the breech bolt is moved forward, the rod r is carried clear of the rear plate J. The cartridge belt passes over the rear end of the barrel, and the belt-feeding slide g and rocking- lever Y are carried by the hinged cover. The lever Y is of spring steel, and there is a clearance between it and the cover, so that when the cover is swung down, if the stud z of the lever does not fit into the groove Z at the top of the breechbolt, this end of the lever will spring up without preventing the cover from being fully swung down and locked; then, when the breech-bolt is worked by its handle, the stud of the lever snaps into its groove as soon as the groove comes underneath the stud. The breech mechanism, in addition to the parts already mentioned, comprises a vertical locking-bolt N in the barrel extension C, and a rocking lever 0 and a spring plunger Q, both carried by the guide-block F, which has a pair of fingers f extending on both sides of the locking- bolt N. The barrel, barrel extension, and breechbolt recoil together, until side pins n on the locking-bolt N strike the bevelled tips of the fingers f and pull the locking-bolt away from the breechbolt. About the same time, the barrel extension strikes the rocking-lever 0, which gives an additional backward impulse to the breech-bolt and stops the barrel extension. The rocking-lever O is then caught by the bevelled corners of side lugs c<2> on a tail-stem c of the barrel extension, which is pressed forwards by the spring plunger Q; the rocking-lever is vertically slotted to embrace the stem c. The breech-bolt is brought to rest against the rear plate J by a buffer k, Fig. IV., comprising washers k<2> confined within the longitudinal tubular part of the handle K by a screw plug k<1>. When the breech-bolt is returned forward by the spring R, it trips the lever 0, after which the barrel is also returned forward, and the spring plunger Q helps the spring R. The locking-bolt N is wedged up by a bevel edge of the seat i. The tightness of the closure of the breech-bolt against the barrel is adjusted by screwing the barrel more or less into the barrel extension; the screw connexion is looked in the adjusted position by a spring pawl P, Fig. V., on the barrel extension C, which pawl snaps into short longitudinal grooves B<1> around the end of the barrel B, and the pawl P is locked in place by the side of the breech casing.