Air cylinder with pilot valve in head

Claim 1

A pneumatic control arrangement comprising: a housing including spaced heads of blocklike construction having mutually perpendicular faces and a hollow, cylindrically shaped body connecting said heads at first faces thereof, a reciprocable piston in said hollow body, each of said heads having a threaded bore extending thereinto from a second face opposite said first face thereof, with a complementarily threaded imperforate access plug extending into said threaded bore and closing the same to provide an internal imperforate abutment surface, and a valve bore integrally formed in said head in coaxial relation and accessible communication with said threaded bore and closed by the plug seated therein, with spaced openings each extending through certain ones of said remaining perpendicular faces at right angles to the planes thereof into said valve bore and each of said openings receiving therein a conduit for transporting air under pressure therethrough, a pilot valve unit in each of said valve bores and including annular flow directing means in a position of confinement between one end of the valve bore and an adjacent portion of the plug at the opposite end thereof and a valve member reciprocable with said annular flow directing means, said valve member having integrally formed therewith a valve operator projecting from said valve bore through a reduced diameter end portion thereof in an inner wall portion of said head into actuable relation with said piston, said valve member being spool-shaped and including a cylindrical portion and a spaced follower portion toward the plug end of said valve bore and connected to said cylindrical portion by a reduced, neckeddown portion forming an annular flow passageway for selectively connecting said conduit openings, said valve member having a central bore at least through said follower portion and compression spring means within said valve bore and said central bore, contacting said valve member at one end and said plug abutment surface at the other end thereof, said spring normally biasing said valve member in a position whereby said valve operator extends into said hollow body, certain ones of said conduit openings being normally blocked from each other whereby upon the actuation of said valve operator by the movement of said piston within said hollow body into engagement with the former said valve member is moved correspondingly within said annular flow directing means to position said necked-down portion into communication with said certain ones of said conduit openings, thereby to allow for a flow of fluid therebetween.