Abstract: A high speed and high load operable hydraulic drive cylinder system comprises a principal cylinder (3) with a piston (3a)) defining an upper and a lower chamber (3c, 3d) and a piston rod (3b), and a subsidiary cylinder (2) smaller in pressure receiving area than the principal cylinder and a piston (2a) defining an upper and a lower chamber (2c, 2d) and a piston rod (2b) smaller in diameter than the piston rod (3b).

Abstract: There is disclosed a high speed hydraulic press, having a press machine body (1) that is constructed of a C-shaped frame (1a), a high speed operable hydraulic cylinder assembly (3) with a portion of hydraulic cylinder disposed in an upper part of the press machine body, and a slide (6) that is coupled to the hydraulic cylinder assembly and adapted to be moved thereby vertically up and down, the press comprising: a manifold block (4) having a passage therein and mounted to the hydraulic cylinder assembly directly on a front surface of the cylinder; and a control valve unit (8) that is associated with the manifold block for delivering a pressure fluid into the hydraulic cylinder via the passage in the manifold block while controlling at least one of parameters of the pressure fluid including flow rate and pressure thereof.

Abstract: A high speed safety circuit arrangement is provided for a hydraulic press which is driven by a hydraulic cylinder assembly constituted by a principal cylinder unit and a subsidiary cylinder unit. The circuit arrangement comprises a servo valve disposed in one of at least a pair of conduit lines for supplying a pressure fluid from a source thereof into the principal cylinder unit and the subsidiary cylinder unit, a first logic valve disposed in the other of the conduit lines and switched on and off and by the servo valve and a first electromagnetic valve for opening and closing that other conduit line, a second and a third logic valve of which each is switched on and off, and at least one is selectively actuatable, by a second electromagnetic valve to interconnect an upper and a lower chamber of the principal cylinder unit in a hydraulic circuit.