Detent mechanism for hydraulic control valve

Claim 1

A DETENT DEVICE FOR RELEASABLY HOLDING A TUBULAR DETENT CARRIER IN A DEFINED POSITION OF AXIAL MOTION ALONG A BORE IN A BODY PART IN WHICH THE DETENT CARRIER IS SLIDABLE, AND WHEREIN FLUID ENTERING THE DETENT CARRIER AT ONE END THEREOF AT A PREDETERMINED PRESSURE VALUE EFFECTS RELEASE OF THE DETENT CARRIER FOR AXIAL SLIDING MOTION IN THE BORE, SAID DETENT DEVICE COMPRISING: CAM FOLLOWER MEANS CARRIED BY THE DETENT CARRIER FOR AXIAL MOVEMENT THEREWITH AND FOR SUBSTANTIALLY RADIAL MOVEMENT RELATIVE THERETO TO AND FROM A DETENT DEFINING POSITION IN WHICH THE CAM FOLLOWER MEANS PROJECTS PARTWAY OUT OF THE WALL OF THE DETENT CARRIER THROUGH A HOLE THEREIN TO ENGAGE IN A CIRCUMFERENTIAL GROOVE IN THE BODY PART WHICH OPENS TO THE BORE; A CAM MEMBER AXIALLY SLIDABLE IN THE DETENT CARRIER, SAID CAM MEMBER HAVING A COAXIAL BORE THERETHROUGH AND HAVING A CAM SURFACE ENGAGEABLE WITH THE CAM FOLLOWER MEANS TO MAINTAIN THE LATTER IN ITS DETENT DEFINING POSITION WHEN THE CAM MEMBER IS IN ONE AXIAL POSITION RELATIVE TO THE DETENT CARRIER, SPACED FROM SAID ONE END THEREOF, AND BY WHICH THE CAM FOLLOWER MEANS IS RELEASED FOR RADIALLY INWARD MOVEMENT OUT OF SAID DETENT DEFINING POSITION WHEN THE CAM MEMBER IS MOVED OUT OF ITS SAID ONE AXIAL POSITION IN THE DIRECTION AWAY FROM SAID ONE END OF THE DETENT CARRIER; A FIRST YIELDING MEANS IN THE DETENT CARRIER BIASING THE CAM MEMBER AXIALLY TOWARD ITS SAID ONE POSITION; A FLUID PRESSURE RESPONSIVE PLUNGER SLIDABLE AXIALLY IN THE INTERIOR OF THE DETENT CARRIER, SAID PLUNGER HAVING A COAXIAL BORE THERETHROUGH AND HAVING A MOTION TRANSMITTING CONNECTION WITH THE CAM MEMBER TO MOVE THE SAME AGAINST ITS BIAS AS A CONSEQUENCE OF SUBJECTION OF SAID PLUNGER TO FLUID PRESSURE; MEANS IN THE DETENT CARRIER SPACED FROM THE OTHER END THEREOF PROVIDING A VALVE SEAT THROUGH WHICH PRESSURE FLUID MUST FLOW BEFORE THE PRES-