GB523809A - Improvements in or relating to hydraulic control systems - Google Patents

Abstract

523,809. Fluid-pressure servomotor-control systems. DORNHOFER, E. Jan. 14, 1939, No. 1358. Convention date, Jan. 14, 1938. [Class 135] In servomotor controls of the type in which a piston 2 is moved into any one of three positions by corresponding movements of a controlling member 7a, an auxiliary valve 6, for determining to which end of the cylinder 1 fluid pressure shall be supplied when the controlling member 7a is moved to the intermediate position m, is connected with lost motion to the valve 7 (rigid with member 7a), the connection shown being a single tooth on the valve 6 engaging a recess in the valve 7 which is longer than the tooth by half the distance of movement. In the position of Fig. 1, pressure fluid from the conduit 15 is led by a diametrical bore in the valve 7 to a conduit 9, whence it passes to the sump either via one recess 16 in the valve 6, the conduit 12, the cylinder 1, and the conduits 14 and 21, or by the other recess 16, the conduit 11, the cylinder 1, and the conduits 13 and 12, the particular route of the two depending on the position of the valve 6, i.e.. on whether the control member 7a has been moved to the position m from v or from p. In the positionsvorr, the valve 7 feeds pressure fluid direct to one of conduits 11 or 12, at the same time connecting the other to the discharge conduit 20, and breaking the connection between conduits 13, 14 and 21. The valve 6 is prevented from slipping unintentionally out of position by a spring-pressed plunger 22 engaging recesses therein.