GB593135A - By-pass valve for hydraulic motors - Google Patents

Abstract

593,135. Hydraulic control valves. ADEL PRECISION PRODUCTS CORPORATION. April 11, 1944, No. 6652. Convention date, April 9, 1943. [Classes 69 (ii) and 135] [Also in Group XXXIII] A control valve for byepassing the flow from one end to the other of a hydraulic motor, especially for operating the landing gear of an aircraft, comprises the valve A arranged between the supply lines B, C to the ends of a motor E for operating the landing gear F. A distributing valve D controls the supply and exhaust of pressure fluid from a supply line G and an exhaust line H. As shown, when the landing gear is being lowered, pressure developed in the lower end of the motor E acts on a check valve 20 which opens to byepass the pressure fluid through a passage J to the top end of the motor cylinder, thus assisting the normal delivery from the supply pump through valve D. Towards the end of the stroke of the motor, the pressure builds up in the line C and the valve 20 closes, and the pressure from the lower end of the motor also builds up sufficiently to overcome a check valve 22 in a sliding piston member 7 to exhaust along line B to valve D and line H. For operation in the other direc- - tion, to raise the landing gear, the pressure fluid is supplied to line B and moves the piston member 7 to seat on a seating 9 to close the byepass passage J and open a passage 10, controlled by a check valve 12, to the lower end of motor E. The exhaust from the top end of the motor takes place through the line C directly back to the valve D and line H. Various different constructional forms of the valve are shown and described. U.S.A. Specification 2,267,284 is referred to.