Manually operable pilot valve

Claim 1

A manually operable pilot valve for actuating the pressure responsive valve assemblies of a fluid motor control valve system providing respective branch pipeline control circuitry connecting the motor inlet chamber and motor outlet chamber through respective pressure responsive valve assemblies to a fluid pump for opposite directional supply of motive fluid to the fluid motor comprising an elongated body member having a longitudinal through bore counterbored at its opposite ends to form enlarged piston chambers, the inner annular end walls of which define an outwardly facing valve seat, respective inlet ports leading from said end piston chambers through one side face adjacent said ends for continuously connecting the respective end chambers to the motor inlet chamber through respective first and second branch pipeline control circuitry and outlet porting means leading from the through bore inwardly from its opposite ends through said one side face said outlet porting means constituting the sole outlet connection from said through bore and continuously connecting said through bore to the motor outlet chamber line through said first and second respective branch pipeline control circuitry; respective poppet valve means having through bores extending from end to end permitting free fluid circulation therethrough assuring free shuttling of the poppets disposed for axial guided movement within the respective opposite ends of said through bore and skirted annular piston portions extending axially of the oppositely facing outer ends toward the outer end of said piston chambers; respective end closure plates fixed to the opposite ends of said body member and having inwardly directed, annular sleeve portions received in said respective piston chambers and sealingly guidingly receiving said respective piston portions of said poppet valve elements; respective biasing springs acting between the inner ends of said skirted annular piston portions and the opposing wall face of said end closure plates to normally bias said poppet valve elements into sealing engagement with said respective valve seats to block the flow of motive fluid from said piston chambers into the opposite ends of said through bore to said outlet porting; and manually operable actuator plunger means disposed in said valve body including a plunger in said through bore between the opposing ends of said poppet valves for selective movement in opposite directions to effect throttling unseating movement of a selected poppet valve to permit controlled fluid flow past the selected poppet from the associated branch pipeline control circuitry establishing a pressure differential upon and effecting a controlled opening movement of the pressure responsive valve assembly of said associated branch pipeline control circuitry and a supply of motive fluid at a controlled flow rate in the selected direction to drive said fluid motor.