Flat-lapped valve cartridge assembly with caged poppet

Claim 1

A relief valve assembly made entirely of metal and comprising, in combination, a metallic tubular support defining a relief valve passage therethrough and having at one end on an outer face thereof a valve seat, and at the other end an outwardly-projecting flange defining an annular recess between one face and the exterior of the tubular support and having an end portion projecting over the recess and forming a reentrant tip portion, the flange engaging and permanently and fixedly retaining a metallic poppet cage, the poppet cage being formed with a central annular body and a plurality of struts extending therefrom, each strut having an in-line end portion permanently bent upon iTself in a 180* turn and having the tip end thereof snugly engaged and retained in the recess by the reentrant tip portion of the flange; a metallic valve poppet movable within the cage towards and away from the valve seat, to open and close the valve passage, the interior of the poppet cage closely abutting the outer periphery of the valve poppet and serving as a track along which the valve poppet slides in its movement toward and away from the valve seat; and a metallic coil spring within the cage retained at one end against the poppet-cage and at the other end against the valve poppet, biasing the poppet toward the valve seat, and retaining the poppet in a closed position at fluid pressures applied against the valve poppet up to a predetermined minimum, the valve poppet at fluid pressures in excess of said minimum overcoming the biasing force of the coil spring and moving away from the valve seat, to open the relief valve passage.