Patent GB-598658-A (GB)
Title: Improvements in or relating to ammunition-belt feed mechanisms for automatic firearms
IPC: F41A9/51
Filed: 1944-10-11
Abstract: 598,658. Cartridge feed mechanism. BRISTOL AEROPLANE CO., Ltd., and FONSECA, E. C. M. D'ASSIS-. Oct. 11, 1944, No. 19621. [Class 92 (ii)] Relates to cartridge feed mechanism for automatic firearms of the kind which includes mechanism for separating the cartridges from that type of link consisting of two partcircular clips. According to the invention, the mechanism first separates the leading clip 24, Fig. 13, of each link and thereafter the trailing clip, both clips being removed from their associated cartridges 21 in a direction laterally of the cartridges. In the construction shown in Figs. 6 and 7, the cartridge belt is fed by a poweractuated mechanism between the ammunition box and the gun to the inlet mouth 34 of the feed mechanism housing 55. The feed mechanism includes a rack-andpinion device 40, 41 which are driven when the gun recoils and which combine with a clutch 100, 101, and a pawl - and - ratchet mechanism 46, 47, to impart a step-by-step movement to a shaft 39 on which the pinion 40 is loosely mounted. One end of a spring 37 is attached at 38 to the shaft 39 and the other end is connected to the end part 50a of a composite tube which end part carries a spindle 104 on which is mounted a pinion 76 serving to drive two shafts 60, 65. The shafts 60, 65 rotate anti-clockwise as seen in Figs. 7 and 13. Shaft 60 serves to feed the ammunition belt towards the stripping mechanism and is fitted with two sprockets 57, 59 for engaging the cartridge cases and a central sprocket 58. The other shaft 65 has fitted to it two sprockets 69, and with each of these is associated a similarlyshaped sprocket 68, each of which is urged in an anti-clockwise direction, Fig. 7, by a spring 74. Pins 72 on sprockets 68 enter grooves 73 in sprockets 69 to limit the movements of sprockets 68. When a link is stripped from its cartridges it passes down a discharge shoot 36 past a spring-controlled deflecting plate 78, and the cartridges pass down a shoot 35 towards the gun. Operation.-When a shot is fired, the stressed spring 37 rotates shaft 104 which in turn rotates shafts 60 and 65, the spring being subsequently re-stressed by the rack-and-pinion mechanism 40, 41. The sprockets 57, 59 thereupon drawing the belt through inlet 34 with the links located between spaced rails 56. As the shafts 60, 65 rotate, the extremities 26 of the leading clip 24, which is double-armed, engage the peripheral edges of one tooth on each of the floating sprockets 68, and as the rotation continues, these teeth push the clip to the position shown in Fig. 13, the rails 56 serving to hold the cartridge against similar lateral movement. Upon further rotation, a tooth on the sprocket 58 of shaft 60 engages the trailing edge 29 of the single arm trailing clip 25 of the link, while teeth, one on each of the sprockets 69, engage the leading edge 27 of clip 25. By this combined action the clip 25 is removed from the succeeding cartridge and is then discharged down the shoot 36. To prevent the last round from passing out of the feed mechanism, spring-controlled fingers 81, 81a are mounted on shaft 65 and are urged towards the separated rounds adjacent shoot 35. When the last round passes the fingers, the latter rotate and causes the rotation of arms 84 on a shaft 85. Arms 84 carry a plate 87 which, when lowered upon rotation of the arms, reduces the effective width of shoot 35 and holds the last round against movement. In a modification, an electric motor is used to stress the spring 37.