GB520123A - Improvements in and relating to control apparatus for hydraulic systems - Google Patents

Abstract

520,123. Valves for hydraulic systems. RICE, J. H. Sept. 2, 1938, No. 25161/39. Divided out of 520,078, [Group XXX] [Class 69 (ii)] A valvedistributing gear for hydraulic systems, such as electro-hydraulic systems in which a constant delivery oil pump driven by an electric motor is used to convert rotary into reciprocatory motion, comprises piston valves 46, 47 slidable in cylinders 44, 45 and acting to control the supply of the pressure medium to outlet pipes 48, 49 which may direct the pressure fluid to primary and secondary. turns for operating conveyer mechanism as described in Specification 520,078, [Group XXX]. The valves 46, 47 are controlled by pistons 57, 58 in cylinders 55, 56 supplied with the pressure medium by a pilot valve 52, which is also a piston valve. In the position shown in Fig. 3 the pilot valve is set so that the pressure medium passes via a pilot passage 50 and inlet channel 53 to the cylinder 55. The piston 57 is thus raised at the same time the piston 58 drops under the action of gravity or of a lever 65 operated by the piston 57. The cylinder 56 is connected to exhaust. The flow of medium is thus cut off from the pipe 48 and opened to the pipe 49. On moving the valve 52 to the left the operation is reversed, and the flow to the pipe 49 is cut off and the flow to the pipe 48 opened. The inlet pipe is fitted with a control needle valve. The lever 65 may be extended and fitted with spring-controlled levers 70, 71 which operate levers 78, 79 respectively in their upward movement' only and the levers 78, 79 control valves of pumps, or other hydraulically actuated mechanisms operated by a piston controlled by the valve-distributing gear described.