GB639712A - Improvements in or relating to feed mechanism for automatic guns - Google Patents

Abstract

639,712. Automatic guns. HYDRAN PRODUCTS, Ltd., and MOTLEY, L. Feb. 23, 1946, No. 5705. [Classes 9 (i), 92 (i) and 92 (ii)] The breech device of an automatic gun constitutes a firing chamber adapted to enclose and support the successive rounds of ammunition at the moment of firing, the breech device being longitudinally split and adapted to open laterally to admit each round and then to close so as to enclose and support said round. In the construction shown, each projectile 4, Fig. 1 is mounted in a tube 3 which also contains the propellant charge and which is linked to other tubes to form a belt. In use this belt moves downwards to bring each tube and its projectile in line with the gun barrel 1, the tube being held between the two parts 5 of a split breech-block. When a round is fired pistons in each of a pair of cylinders 21 each move a corresponding rod 19 which, by racks 20, rotate threaded sleeves 17 which serve to open out the two parts of the breech-block. A piston in a third cylinder 27 causes a rod 28 to actuate rack-and-pinion mechanisms in casings 30 for advancing the belt to bring another tube into the firing position. Springs serve to return the pistons to their forward positions when the gas pressure falls, and the rods 19 may also serve to control the movements of lockiug lugs 22 which positively hold the parts 5 of the breech-block in the closed position. The forward end of each tube is bent over at 11 and this part 11 is deformed by the projectile on firing so that it projects slightly into the barrel and effects oburation. The tube must therefore be moved longitudinally away from the barrel to allow the belt to advance, and for this purpose the lugs on the tubes for the hinge pins are spaced to permit such movement, and a member 45, Fig. 3, positively moves the tube of a fired round away from the barrel 1. As shown, the member 45 is connected to a fork 42 which straddles the barrel, and the fork is connected to a sleeve 41 with which is associated springs 43 and 34, and a catch 40. When a round is fired gases enter a port 31 and act on a piston 33 which compresses the spring 34, the piston being then held in its rear position by a catch 35. The breech-block parts 5 are now opening and by reason of thin inclined ends move links 37, 38 to release the catch 40, thus enabling the spring 34 to overcome spring 43 and to drive sleeve 41, and thus the projectile tube, to the rear. The fork 42 at the end of its stroke moves a lever 46 linked to means for lifting the catch 35 ; the piston 33 can now move to its forward position, and when the next tube has been advanced to the firing position the various parts return to the position shown. The gases of explosion may pass to the rear through a nozzle 8, Fig. 1, in the case of a recoilless gun. Specification 639,766 is referred to. The Provisional Specification describes also a modification in which the tube 3 is closed by a shear plate which is blown away when a predetermined pressure is generated.