Abstract: 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.

Abstract: There is described an improvement in solenoid pilot operated valve using a spool/piston assembly which is operated by fluid pressure in a pilot chamber, wherein a piston is slidably mounted on one or both ends of a spool and independently returnable to its initial position upon relieving the pilot chamber of fluid pressure.

Abstract: A piston braking device for a hydraulic or pneumatic cylinder, employing an annular braking plate loosely fitted on the piston rod of the cylinder and rockable into a tilted position relative to the piston rod upon actuation by a plate drive means, and a brake control mechanism operative to apply a counter pressure on the braking plate to maintain or reset the braking plate in a normal right angle position, the braking plate having braking portions on its inner periphery which braking portions are pressed against the circumference of the piston rod to apply friction brakes thereto in a manner which increases the braking force in proportion to the propelling force of the piston rod.

Abstract: 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.

Abstract: In a spool-sleeve type change-over valve, the axial width of the intake passage is reduced relative to that of the discharge passage within a range in which the same cylinder response as attained by intake and discharge passages of the same axial width is retained.

Abstract: 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).

Abstract: There is described a solenoid pilot operated change-over valve of the type using a spool/piston assembly which is movable in response to pressure prevailing in a pilot chamber, wherein the effective diameter of a drain valve seat in the pilot chamber is formed at least 1.4 times greater than that of a pilot valve seat on the piston through which the pilot chamber is communicable with an input port of the valve. The spool/piston assembly is reset to the initial position upon de-energization of the solenoid before the pilot valve seat is completely closed by a plunger.

Abstract: A pilot-controlled electromagnetic valve having a pilot valve mounted on a member which is supported movably relative to a solenoid plunger and a main valve and connected to the plunger through a spring such that a pilot orifice is opened when the plunger approaches a fixed core of the solenoid undergoing a stronger magnetic pull.

Abstract: A poppet type change-over valve assembly suitable for switching a fluid flow direction and capable of dealing with a large fluid flow with a small valve displacement and small valve operating force. The valve assembly characteristically comprises an annular float valve which is loosely mounted around a main valve body and has parallel or concentric outer and inner sealing edges for engagement with conical valve seats which are formed on the main valve body and an inner wall surface of the valve casing. The annular float valve is adapted to be tightly held between the conical valve seats of the main valve body and the valve casing by cooperation of the main valve body and a fluid pressure prevailing in the valve chamber when the valve is switched to a desired change-over position thereby establishing a tight seal around the main valve body for connecting a fluid inlet port with a selected fluid output port of the valve.

Abstract: In a spool-sleeve type electromagnetic change-over valve the dimension of the non-valving holes in the axial direction of the sleeve is made considerably larger than the comparable dimension of the valving holes and the total area of a row of the non-valving holes is similarly made much larger than a row of the valving holes so that the spool stroke is kept small while increasing the air flow capacity of the valve.