Shoketsu Kinzoku Kogyo Kabushiki Kaisha

Tomomitsu Iizumi

A control valve is provided between a direction-changeover valve and an actuator in a fluid-pressure operating system. This control valve includes a body having an inlet and an outlet; a fluid passage interconnecting the inlet and the outlet; a valve body and a valve seat which are cooperative with each other to define a clearance therebetween and positioned within the fluid passage; a spring for resiliently urging the valve body toward a constrictive position to where a diminished clearance is defined between the valve body and the valve seat; and pressure responsive means for displacing the valve body in an opposite direction against the force applied by the spring thereby enlarging the clearance and bringing the valve body to its fully open position. An adjusting rod enabling adjustment of the first position of the valve body is provided, and a pilot piston operates under a pilot fluid pressure applied through a pilot port for forcing the valve body to its fully open position.

Control valve

A flow rate control valve for use with an actuator, in which a fluid may be quickly discharged from a cylinder in the actuator on a return stroke of a piston which is slidingly fitted in the cylinder. The valve includes a casing defining a fluid inlet port and a fluid outlet port, a fluid passage interconnecting the two ports, a throttle valve for restricting the opening of the fluid passage, and a pressure-regulating valve which is adapted to be open at pressures over a given pressure level. In this flow rate control valve, the throttle valve and pressure adjusting valve may be combined into a composite valve. An externally adjustable pressure adjusting spring, resiliently biasses the pressure regulating valve.

Flow rate control valve

A fluid circuit including an actuator, a flow-direction change-over valve and a pressure source. The actuator includes a piston-rod-side chamber and a piston-head-side chamber which are partitioned by a piston. In a fluid path leading from the piston-head-side chamber to the flow-direction change-over valve, there is provided a flow-rate-control, pressure-regulating valve assembly for regulating a fluid pressure to be fed into the piston-head chamber, thereby saving energy required for a return stroke of a piston. In another fluid path leading from the piston-head-side chamber to the flow-direction change-over valve, there is provided a check valve and throttle valve assembly. The check valve in the valve assembly may be of a type which allows the flow of a fluid only in the direction towards the piston-head-side chamber (a meter-in control) or may be of a type which allows the flow of a fluid only in the direction from the piston-head-side chamber (meter-out control). For accelerating an advancing stroke of a piston in the meter-in control type actuator at a safe speed, a speed control safety valve and a quick discharge valve assembly is incorporated in the fluid path leading to the cylinder-head-side chamber in the actuator in place of the aforesaid check valve and a throttle valve assembly.

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Tokyo, Japan

Tomomitsu Iizumi