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.

Abstract: A high speed and high load cylinder device is constructed by connecting a piston of a high speed cylinder (1) having a smaller pressure receiving area and a piston of a pressurizing cylinder (2) having a large pressurizing area. The device is provided with a hydraulic circuit for supplying a hydraulic pressure to the high speed cylinder and the pressurizing cylinder. The device has a sequence valve (5) at an intermediate position in a passage (2e) providing in the piston of the pressurizing cylinder for communicating an upper chamber (2.sub.1) and a lower chamber (2.sub.2) of the pressurizing cylinder for opening and closing the passage depending upon a pilot pressure. A pilot pressure is supplied for closing the sequence valve by supplying the pilot pressure to the sequence valve. A high speed/pressurizing switching valve (12) is provided at an intermediate position in a piping (11) supplying the hydraulic pressure to the upper chamber of the pressurizing cylinder in the hydraulic circuit.

Abstract: The present invention provides a complex machine tool wherein the punching center is coincides with the cutting work position so that the range of movement of a workpiece is not subjected to any restriction even during the workpiece cutting work in the same manner as in the workpiece punching work. The composite machine tool comprises a plasma torch (16) mounted on the machine tool body near the working position and arranged to be movable freely such that it can be withdrawn from the working position when a workpiece (5) is subjected to die-punching work, and proceeded to the working position when the workpiece is subjected to cutting work. Futher, the machine tool comprises protecting means (18, 19) for protecting the lower turret (3) and other members mounted adjacent thereto from the dross and heat developed by plasma arc during the workpiece cutting work by the plasma torch.

Abstract: A sprocket wheel of an endless track-type vehicle has a hub and a plurality of sprocket teeth segments fixedly secured to the outermost of the hub to engage a plurality of bushings of an endless track for driving the same. The hub comprises a substantially annular-shaped radially inner part, a substantially annular-shaped radially outer part arranged movably with respect to the inner part by the interposition of a plurality of deformable resilient block segments tightly inserted into an annular space defined by and between the inner and outer parts, and a stopper mechanism for preventing the deformable resilient block segments from an excessive deformation thereof.