GB559410A - Improvements in sequence valves - Google Patents

Abstract

559,410. Valves. VINCO CORPORATION. Dec. 31, 1942, No. 18602. Convention date, Dec. 26, 1941. [Class 135] A three-way valve device for use in hydraulic circuits which are to be controlled according to a predetermined sequence of operation for example a hydraulic circuit operating a clamp on a machine having a hydraulic ram comprises a spool valve 4 normally held by a spring 8 against a resilient stop 10 to close the passage-way between two conduits, pressure in either of the conduits being effective to open the valve. In the system shown in Fig. 1, a pump 24 driven by a motor 25 is connected with a drain connection 29. Pipes 27, 28 lead from the valve 26 to two valves 1, 30 constructed according to the present invention and having pipes 18, 21 and 35, 36 leading to double-acting power-cylinders 31, 33. The three-way valves each comprise a two-landed piston of which the upper land has notches 20 and is adapted to control the connection between chambers 17, 19. The chamber 19 communicates with the conduit 21 while the chamber 17 communicates with the conduits 15, 18, the conduit 15 also being connected by a passage 16 with a chamber below the lower end of the valve. When the pipe 27 is under pressure, fluid passes through the conduit 15, chamber 17 and pipe 18 to the lower end of the cylinder 31. When the piston 32 reaches the end of its stroke pressure builds up beneath the valve to move it against the action of the spring 11 to connect the chambers 17, 19 and allow fluid to pass through the pipe 21 to the left-hand end of the cylinder 33. During both these movements fluid is exhausted from the other ends of both cylinders through the valve 30. A similar series of movements take place when the pipe 28 is under pressure. Specification 559,346 is referred to.