GB864499A - Improvements in and relating to fluid flow control valves - Google Patents

Abstract

864,499. Valves; hydraulic apparatus. PARKER-HANNIFIN CORPORATION. Dec. 3, 1958, No. 38985/58. Classes 69 (2) and 135. A control valve for an hydraulic motor comprises a valve 45 slidable in a bore 11, Fig. 1, intersected by a pair of exhaust passages 26, 27 leading to a common exhaust chamber 24, by a motor passage 36 adjacent one exhaust passage 26, by a pressure supply passage 13 between the motor passage and the other exhaust passage 27, by an intake passage 15 outward of exhaust passage 27 and connected to the pressure source e.g. pump 17 and to the supply passage via passage 14 and check valve 20, Figs. 2, 6, and by a by-pass passage 30 adjacent the intake passage, the valve in its neutral position as shown in Fig. 1 closing the motor from the supply and exhaust passages but connecting the intake and by-pass passages through the bore 11, and the valve also being movable to open the motor to the supply or to the exhaust passage and close the connection between the intake and by-pass passages, a first passage 81, Fig. 6, connecting the by-pass to the exhaust chamber 24, a second passage 83 leading the by-pass to the exterior of the housing and means e.g. of screw plugs 82, 84a respectively for selectively connecting the by-pass to the exhaust chamber or the housing exterior. With the exterior passage closed, one piston valve 45 having four lands with metering notches at 50 controls a double-acting motor 39 and a second piston valve 69 having three notched lands and using one motor passage 62 controls a single acting motor 65. With both valves in neutral position, the pump is unloaded via the by-pass, bores 11 and 12 and passage 28 leading to exhaust. With the passage 81 to the exhaust closed, the passage 83 is connected to the intake 15 of a second valve housing B, as in Fig. 6, of which the exterior passage is closed whereby two further motors 85, 86 may be operated when the valves of housing A are in neutral. To permit any of the motors to be operated at the same time, a connection 92, Fig. 6, leads pressure from the supply passage 13 of housing A to the supply passage of housing B. A tubular relief valve 32, Fig. 2, connects the supply passage 13 to exhaust passage 27.