Snap operator for pressure fluid valve

Claim 1

A fluid-actuated, snap-acting operator, particularly for a valve, comprising: housing means defining a bore therein; actuator means positioned within said bore for movement between first and second positions for actuating a selected member, such as a valve spool; said actuator means including piston means positioned within said bore in slidable sealing engagement with said housing means for movement between said first and second positions, said piston means dividing said bore into first and second chambers; said actuator means also including a portion fixedly connected to said piston means and disposed within said second chamber, said portion including recess means therein; inlet passage means in communication with said first chamber for supplying pressure fluid to said first chamber for causing movement of said piston means from said first position to said second position; control means coacting with said actuator means for releasably maintaining said actuator means in said first position while permitting release of said actuator means and movement thereof to said second position when the pressure of the fluid in said first chamber exceeds a first predetermined magnitude, said control means coacting with said actuator means when in said second position for causing return of said actuator means to said first position when the pressure of the fluid in said first chamber is less than a second predetermined magnitude, said second predetermined magnitude being substantially smaller than said first predetermined magnitude; said control means including detent means coacting with said actuator means for normally releasably maintaining same in said first position, said detent means including a movable detent ball normally disposed in engagement with the recess means of said portion of said actuator means and movable relative thereto, and a detent sleeve member movably disposed within said second chamber in surrounding relationship to said portion of said actuator means and positioned for coaction with said detent ball for controlling the movement thereof relative to said actuator means; said detent sleeve having first wall means defining a conical opening therein and second wall means defining a substantially cylindrical opening in continuous relationship with said conical opening at the large diameter end thereof, said detent ball being disposed within and movable between said conical opening and said cylindrical opening, said ball being adapted to be at least partially disposed within said recess means when said ball is disposed within said conical opening; bearing means stationarily positioned relative to said housing means and having a portion thereof slidably received within said cylindrical opening, said bearing means having a surface in bearing engagement with said detent ball for maintaining said ball within said detent sleeve; and said control means further including resilient means coacting with said detent means for normally resiliently maintaining said detent ball in engagement with said recess means so long as said actuator means is in said first position and the pressure of the fluid within said first chamber does not exceed said first predetermined magnitude, said resilient means having a first portion thereof resiliently urging said actuator means in one direction and a second portion thereof coacting with said detent sleeve for resiliently urging same in the opposite direction, whereby said resilient means causes said actuator means to be returned from said second position to said first position and causes said detent means to again engage said actuator means when same rEturns to said first position whenever the pressure of the fluid in said first chamber is less than said second predetermined magnitude.