GB723954A - Cocking mechanisms for automatic guns - Google Patents

Abstract

723,954. Cocking mechanisms for automatic guns. DUNLOP RUBBER CO., Ltd., TREVASKIS, H. W., and DEWAR, D. Oct. 22, 1953 [Nov. 19, 1952], No. 29184/52. Class 92(2). A fluid pressure jack mechanism for initially cocking an automatic gun comprises a cylinder 1 connected through an aperture 3 in the cylinder head 2 to a source of fluid pressure, an annular piston 5 slidable in the cylinder and having a tubular tail-piece 6 in which slides a second annular piston 15 with a piston rod 13 adapted to contact a part of the bolt of the gun ; a skirt 18 extending from the front face of the piston 15 has a guiding surface 19 and an annular recess 20 and spring latches 22 with heads 23 are secured in the cylinder head 2, the arrangement being such that on the piston 15 moving toward the head 2, the latches 22 are first deflected by the surface 19, the latch heads 23 then moving into the recess 20 to hold the piston 15 in the fully contracted position. This arrangement prevents the piston rod 13 " wandering " outwardly due to vibration to be struck by the reciprocating bolts. In operation, a valve is opened to admit pressure fluid into the cylinder 1 and both pistons 5, 15 are moved back, the latches 22 being deflected to allow the latch heads 23 to move out of the recess 20. Air behind the pistons escapes through apertures 8 and ports 12. The piston 5 slides in the cylinder 1 until it abuts a flange 4 and the piston 15 slides in the tail 6 of the piston 5 until it abuts a sleeve 10. As the piston rod 13 moves outwardly a spring-loaded spigot 27 therein contacts the bolt and is forced back against a spring 28 until a flange 14 at the end of the piston rod 13 contacts the bolt and moves it rearwardly until the gun is cocked. The valve is then operated to allow the pressure fluid to flow back to the reservoir, the jack however remaining in the extended position. On firing the bolt moves forward and carries the piston rod 13 with it until at the forward position of the bolt, the spring-loaded spigot 27 reacting against the bolt forces both pistons in to their fully contracted positions where they are held by the latches 22.