Momentary contact valve

Claim 1

A momentary contact valve for selectively porting pressurized fluid from a source to a receiver comprising: an elongated valve housing having first and second ends interconnected by a bore extending therethrough including a pair of inverted tapered valve seats comprising a part thereof located substantially midway therein with open receiver ends at each opposite housing bore end adaptable to receive solenoid operators, first port in said housing adaptable to be connected to a supply source entering said bore perpendicularly between said tapered valve seats for supply of the pressurized working fluid therein, second port in said housing adaptable to be connected to a first receiver entering said bore perpendicularly adjacent first tapered valve seat, third port in said housing adaptable to be connected to a second receiver entering said bore perpendicularly adjacent second tapered valve seat, valve means in said housing shiftable from a first position blocking fluid communication between said first and second ports while allowing fluid flow between said first and third ports to a second position allowing fluid flow between said first and second ports while blocking fluid communication between said first and third ports, a pair of diametrically opposite electric solenoid operators disposed inside said housing open receiver ends in an axial alignment with and on opposite sides of said valve means in an operable relationship therewith including means for maintaining said valve means in one of said positions and means for shifting said valve means from said first to second positions and vice versa when one of said solenoids is momentarily energized, means for substantially pressure forcing said valve means in one of said positions, including fluid operable means wherein said valve means include an internally piloted movable stem assembly in an axial alignment with said solenoids, having a reduced size center portion interconnecting two larger size valve members that provide opposing larger diameter outward end faces including larger size seals adjacent said end faces and two smaller size inward seals at said reduced size interconnection adjacent said center portion thereof, said outward end faces having large surface area at each stem end, said inward seals having smallest surface area of said valve members and said diametral difference between said larger and smaller diameter seals providing a differential area surface, said surface when exposed to pressure exerting end forces of different magnitude for shifting said valve means into said different directions when desired and for maintaining said valve means in at least one of said positions by a pressure force unbalance the fluid exerts on said valve means, said internal pilot of said stem assembly including a flow passage continuously communicating with said first fluid port inside said housing bore by way of a cross passage provided therein, said pilot passage exiting centrally at each of said end faces of said valve members into a solenoid cavity at solenoid open end opposite said solenoid exhaust apertures at each housing end, said solenoid operator cavities further including a spring loaded plungers axially movAble therein between said end faces of said stem and a seat of said solenoid exhaust apertures in a dimensionally changing axial relationship which varies with the position said stem assembly assumes axially inside said valve housing bore during valve operation when one of said solenoid operators is energized electrically, said solenoid plungers thereby selectively moving between an open position spaced from said end faces of said valve members and defining a fluid cavity therebetwween and a closed position in blocking engagement with said end faces of said valve members while allowing said fluid cavity into atmospheric exhaust via said solenoid exhaust apertures, wherein when one of said solenoid operators is momentarily energized said plunger thereof being at a given axial distance between said end face of adjacent valve member and said solenoid exhaust seat is moved into said open position until said solenoid exhaust aperture is closed by said plunger and said solenoid cavity is pressurized by fluid exiting said pilot passage forcing said stem assembly to shift forward thereby increasing the axial distance between said plunger and said end face with resultant change in said axial relationship therein, and when said operator is deenergized, said plunger returns to said closed position over said end face by the spring action dictating utilization of springs that can tolerate said axial distance change.