GB951691A - Improvements in or relating to control valve systems for controlling fluid motors - Google Patents

Abstract

951,691. Fluid-pressure apparatus. SPERRY RAND CORPORATION. June 26, 1961 [June 27, 1960], No. 22949/61. Heading F1P. [Also in Divisions F2 and G3] A bank of manually-operable spool-valves is made up of an inlet section 10, an intermediate section 12, and an outlet section 14, each section housing a manually-operable spool-closure 23, 35, 37, respectively. Any number of intermediate sections 12 may be used or the bank may comprise only inlet and outlet sections. Each closure controls a pair of working ports leading to a motor but one of the two ports in the outlet section 14 is blanked off. A supply port is provided in the inlet sections 12, which port opens into a passage 54 in series with passages 56, 58 in the other two sections, respectively, each of which passages is intersected by a check-valve bore 60, 61 or 62 that is connected by the associated valve, not shown, to a corresponding pressure port 64, 66 or 68 for the related spool-closure bore. Each of the latter also incorporates pairs of motor ports 70, 72, and pairs of return ports 74, 76. The return ports lead through series passages 78, 80 in the upper and lower parts of each section to a common port 82 in the outlet section. Each spool bore has a spool controlled by-pass passage 84, 86, the passages in the various section being arranged in series between the supply port and port 82. The spools are each urged to the neutral position shown by a spring 99 between retainers 101, 103 in which position the motor ports are closed and the supply is by-passed to the port 82 or to a separate external port 128. A main relief-valve is provided to ensure a regulated flow rate through the by-pass passages 84, 86 only when all the spools are in the neutral position, which valve is disposed in the inlet section 10, Fig. 2, and consists of a main spring- loaded valve 102 in which is seated a pilot valve 104, the upper and lower faces of the main valve being subjected to supply pressure upstream and downstream, respectively, of a throttle 110, the latter path also including a restriction 114. The main valve 102 controls the connection of the supply passage 54 to an isolated exhaust passage 124 which meets similar passages in the intermediate and outlet sections. - When the supply pressure attains a given level it unseats the pilot valve 104 to open the space beneath the main valve to the passage 124, whereupon the main valve opens. An hydraulic piston-and-cylinder device may be connected across ports 82 and 128 through a four way valve, the speed of the piston of which device is determined by the flow through the by-pass passages which is regulated by adjustment of the quantity of fluid exhausted through the main relief valve, which in turn depends upon the setting of the throttle 110 and the relief-valve spring. Specification 517,877 and U.S.A. Specification 2,289,567 are referred to.