GB590897A - Improvements in volume compensating devices for hydraulic control systems and the like - Google Patents

Abstract

590,897. Hydraulic brakes. STOKES, M. W., and EXACTOR CONTROL CO., Ltd. July 19, 1944, No. 13860. [Class 103 (i)] In a compensating device for the master cylinder of an hydraulic control system and comprising a master cylinder 3 in which a piston 10 reciprocates, a cover or closure 6 for the cylinder and opposed to the piston face, a return spring 27 disposed between the closure and the piston, and a liquid reservoir in communication with the cylinder through a non- return valve, compensating liquid is admitted to the cylinder by a non-return valve 24 operated by telescopic members 28, 32, 36 and adapted to be unseated automatically when the piston is fully retracted but to be closed by the difference of fluid pressure on opposite sides of the piston on forward piston movement. The valve 24 seats against the cup-leather 17 of the piston 10 and closes a port 21 therein, the port being open at its other side through passages 20 with an annular recess 19 in the piston; a passage 22 in the cylinder wall permanently connects the recess 19 with a port 4 leading to the supplementary reservoir and the packings on the piston are disposed one behind and one in front of the passage 22. The telescopic support 28, 32, 36 of the valve 24 is adapted to hold the valve clear of the piston face when the piston is fully retracted and to be drawn to that position by contact with a flange 25 on a cage 26 having an out-turned end 26a engaged between the spring 27 and the cupleather 17. Forward movement of the piston closes the cup-leather on to the valve.