GB486773A - Improvements in or relating to machine gun firing means - Google Patents

Abstract

486,773. Firing devices for machine guns ; hydraulic apparatus ; valves. DUNLOP RUBBER CO., Ltd., WRIGHT, J., and TREVASKIS, H. Dec. 9, 1936, Nos. 33793/36 and 26914/37. [Class 92 (ii)] [Also in Group XXIX] Relates to hydraulic systems for the remote control of the firing or bolt-release mechanisms of one or more automatic guns on aircraft as described and claimed in Specification 486,774, in which liquid can be freely circulated through the system under a pressure insufficient to operate the guns, a branch circuit through the firing motors being brought into action when the firing button is operated, to increase the pressure to a degree sufficient for firing. According to the present invention, a return pipe in the branch circuit connecting the motors to the reservoir is made wholly or in part of reduced diameter relative to the pressure supply pipes in order to cause a building up of the pressure at the time of firing. Fig. 1 shows the general lay-out of the hydraulic system described in Specification 486,774 in which there is continuous circulation of liquid under pressure from a reservoir 1 through a pump 2, preselector-valve 3 and pipe 7. By moving the control handle 6 of the preselector-valve 3 to the full-line position shown, the liquid is circulated through the branch circuit 8 including the gun-firing valve 10 and the circuit 13, 15 containing the firing button 42. On pressing this button, a flap-valve in the casing 10 cuts off the circuit 8 and brings into circuit a pipe 9 leading to the firing devices on the guns 16, 17 the return lead 19 from which is restricted either by using a small return pipe or by introducing a fine jet at the box 21. Excess pressure is prevented by a relief-valve 11. Fig. 3 shows the flap-valve 28 in the box 10 in the cut-off position. In the normal dotted-line position, liquid circulates to the press-button casing 14 by passages 31, 30, 37 through lift valve 38 and pipe 13 and returns by pipe 15 and passage 26. The press-button 42 closes the pipe 15 and forces liquid through pipe 13 to operate the flap-valve and bring the firing circuits into action.