Improvements in or relating to devices for controlling pressure operated means in fluid systems

摘要

873,514. Fluid-pressure servomotor-control systems; valves. CITRAIN S.A., ANDRE. Aug. 9, 1957 [Oct. 29, 1956], No. 25276/57. Class 135. [Also in Group XXXIV] Means for providing a progressive control of the pressure of hydraulic fluid applied to a servo-mechanism for the operation of brakes, clutches, couplings, &c., comprises a progressively - opening valve consisting of a tapered closure member 1 housed in a body 2 which has a connection 4 to a source of pressure fluid and a connection 5 leading to an output conduit 11 which connects with the servo-mechanism and has a branch leading by way of an output regulator 12 to a return line connecting with the hydraulic fluid reservoir. The conduit 11 also communicates directly with the reservoir through a conduit 17 and chamber 19 when the valve member is in its raised position to which it is urged by a spring 7. On depression of the valve member 1, e.g. by a pedal, the tapered part of the valve member leaves its seat and the conduit 17 is closed to permit gradual pressurization of the conduit 11. Pressure fluid can escape from the conduit 11 at a rate determined by apertures 14 in a piston 15 of the regulator 12, and when the pressure acting on the upper end of the piston 15 comes into balance with a spring 13 the piston 15 partially obturates an outlet port 16 to provide a leakage flow of constant amount. More than one servo-mechanism, each associated with a separate control valve and regulator, may be operated from a single source of pressure fluid. A construction of control valve is described in which the movable member 1 slides in a pair of coaxial liners in the body 2, the liners being provided with ring-shaped gaskets.