GB515617A - Improvements in or relating to liquid pressure remote control systems - Google Patents

Abstract

515,617. Fluid-actuated valves. AUTOMOTIVE PRODUCTS CO., Ltd., CLENCH, E. C. S., and CARLTON, Q. H., (formerly KAHL, Q. H. H.). March 12, 1938, No. 7786. [Class 135] A liquid-pressure remote control system, e.g., for retractable undercarriages of an aircraft, comprises, as shown, two " dumb-bell " valves 21, 22 controlling a supply of pressure liquid from a pump 10 to a double-acting servomotor 15, both sides of which are normally connected via an exhaust 31 to a reservoir 11, the valves 21, 22 being actuated by liquid-pressure admitted to the chambers 61, 60 from the main supply by an auxiliary valve 37 moved from its central "off" position to either of its two "on" positions by a double-acting electro-magnetic device 47. The switch 57 controlling the device 47 is mounted in the pilot's cabin, and there may be provided limit switches 52, 53, normally closed but respectively opened by the servomotor 15 in each of its two end positions, so that after each actuation the electric circuit is automatically broken to allow the valve mechanism to return to the position of Fig. 1, so that the switch knob 58 may be left up or down to indicate the position of the servomotor 15. Alternatively, the switch 57 may be spring-urged to its central " off " position, in which case, in order to indicate the position of the servomotor 15 a variable resistance associated therewith may be connected through extra contacts on the switch 57 to an ammeter or ohm-meter situated near that switch, this circuit being completed as soon as the knob 58 is moved from its central position and before the contacts for the device 47 are connected. An adjustable throttle 62 may be employed to govern the rate of actuation of the servomotor 15 and the valve 37 may be directly hand-operated by means of a handle 48.