Four-way valve with integral flow controls, common exhaust, and cartridge type pilot valve

Claim 1

A four-way air valve which includes a valve body with a pressurized air supply chamber, a pair of cylinder chambers and a pair of exhaust chambers, and a main valve spool axially movable between two operative positions in a valve spool bore in the valve body to control flow of pressurized air from the air supply chamber to a selected one of said cylinder chambers while simultaneously controlling the exhaust from the other cylinder chamber to a selected one of said exhaust chambers, a top cover releasably mounted on said valve body, and means for moving the main valve spool between the two operative positions, characterized in that: (a) said air supply chamber is disposed centrally along the valve spool bore, with the cylinder chambers disposed along the valve spool bore on opposite sides of said air supply chamber and adjacent thereto, and with the exhaust chambers disposed along the valve spool bore with one of the cylinder chambers on a side thereof opposite to the side adjacent to the air supply chamber; (b) the valve body is provided with a pressurized air inlet port which is connected by inlet passage means in the valve body to the air supply chamber; (c) the valve body is provided with two cylinder ports which are each connected by separate cylinder passage means to one of the cylinder chambers; (d) the valve body is provided with a single exhaust port which is connected by an exhaust passage means to a common exhaust passageway in the valve body, and each of the exhaust chambers is connected to the common exhaust passageway by a separate passage; (e) said means for moving the main valve spool to at least one operative position comprises a cartridge type solenoid operated pilot air valve which includes: 1. a pilot air valve body, and means for releasably securing one end of the pilot air valve body to the four-way valve body; 2. a pilot valve piston movably mounted in a cylinder in said pilot air valve body, and having a front end and a rear end, and provided with an axial shaft which extends axially forward from the pilot valve piston front end and engages one end of the main valve spool, and having an axial bore extended inwardly from the rear end thereof and terminating adjacent the pilot valve piston front end; 3. a pilot valve element retainer releasably seated in the pilot air valve body and having an inner end and an outer end, and with the inner end slidably mounted in the axial bore in said pilot valve piston, and said retainer having an axial bore that extends inwardly from the outer end thereof and terminates in a transverse wall; 4. a pilot valve element movably mounted in the axial bore in the pilot valve element retainer and movable, by a spring mounted in the axial bore in said retainer, to a first operative position to block flow of pilot air to the pilot valve piston cylinder against the rear end of the pilot valve piston and allow exhaust of pilot air from the rear end of the pilot valve piston in said cylinder through exhaust passageway means formed along the outer periphery of the pilot valve element and through the axial bore in said retainer and passages through the front end of said piston and through the piston chamber to an external exhaust passage, and movable by a solenoid armature pusher member to a second operative position to allow flow of pilot air to the rear end of the pilot valve piston, to move the piston and the axial shaft thereon, which in turn moves the main valve spool.