GB486774A - Improvements in or relating to control means for fluid pressure operated apparatus - Google Patents

Abstract

486,774. Firing devices for machine guns. DUNLOP RUBBER CO., Ltd., WRIGHT, J., and TREVASKIS, H. Dec. 9, 1936, Nos. 33794/36, 33795/36, and 26915/37. [Class 92 (ii)] [Also in Group XXIX] A hydraulic system for remotely controlling the operation of one or more automatic guns on aircraft includes two pipes connected in parallel, a continuous flow of liquid being maintained through said pipes from a pump back to a reservoir and thence back to said pump, one of said pipes containing one or more motors for actuating the gun or guns, said continuous flow through this pipe being normally insufficient to operate said motor or motors, the main flow of liquid being normally through the other said pipe which contains a valve whereby the flow therethrough can be stopped so that the whole flow is then through the first mentioned pipe at a pressure sufficient to operate the gun or guns. The system includes, Fig. 1, a reservoir 1, pump 2, and two-way pre-selector valve 3. When this latter is in the " guns off " position, the pump delivery passes back directly to the reservoir by pipes 5, 7 and, when the valve is moved to the " guns on " position, the pump delivery passes to pipe 4 and thence to the branched pipes 8, 9. The pipe 9 communicates with the controlling devices of the guns 16, 17 and thence by pipe 19 with the reservoir and the pipe 8 communicates with an interrupter valve 10 and thence by pipe 12 with the reservoir. A pressure-relief valve 11 is provided. There is a continuous flow through pipe 9 at a pressure insufficient to actuate the guns; the main flow is through pipe 8, the valve 10 being open. When the latter is closed, the whole flow is through pipe 9, and the pressure therein increases sufficiently to operate the guns; the pipe 19 may be, at least in part, of reduced diameter relative to pipe 9, as described in Specification 486,773. The interrupter valve 10, Fig. 3, comprises a flap 28 normally urged by a spring 29 to the open position, permitting flow from pipe 8 to pipe 10. Pressure liquid from the pipe 8 also passes by groove 31 in the flap 28, non-return valve 38 in a plunger 35, and pipe 13 to a valve member 14, Fig. 6, positioned on the chief flying control, and thence by pipe 15 and connection 26 to the return pipe 12 from the valve 10. When the push-button 42 is pushed in against spring 45, the return pipe 15 is obstructed, and further operation of the button transmits pressure through the column of liquid in the pipe 13, the non-return valve 38 now shutting, to move the plunger 35 to shut the valve flap 28 against the spring 29, thus preventing flow to the pipe 12. A constriction 25a ensures the maintenance of pressure in the interior of the valve 10.