| 摘要 |
A fluid power control valve for use with pneumatic or hydraulic pressurized working fluids or a combination thereof comprising a three way valve including a spool with symetrically opposing pistons of differential area at spool extremities of which a small piston of the spool end faces the fluid entrance port whereas the opposite spool end with large diameter piston is blocked from fluid contact by a seal of a centrally situated control rod which passes the spool and protrudes to the outside through the valve end closure for actuation to facilitate shifting of the spool from a valve open first position for cylinder pressurization by the working fluid which moves the spool and the rod assembly sealed toward the end closure constituting a stop, to a second closed position upon actuation of the control rod in terms of a slight motion accompanied by seal cracking and supply of the fluid via clearance hole of the rod to enter behind the large piston of the spool for immediate spool return to the original first position, simultaneously exhausting cylinder and relieving fluid pressure from behind the large piston upon the completion of the cycle, so constructed that the shift of the spool for cylinder actuation can be accomplished externally with very little force to physically move the control rod either manually, by a cam of an electric timer, by pilot pressure of added pilot cap or by other means involving as little as possible axial motion in rod travel, conditions unattainable with other valve designs in existance, other means comprising the automatic self-regulated valve operation with rod end striking a blind end closure for cracking seal to initiate fluid communication behind the large piston and the subsequent shift of the spool for self-reciprocation of the valve without external actuation.
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