Abstract: A method of manufacturing a ring-shaped hydraulic seal (10) produces a cylindrical sealing surface (12) having portions (24) formed of a plastic material and portions (26) formed of an elastomeric material. The method includes the steps of forming a plastic ring (30) and molding an elastomeric material into a cavity (50) in the plastic ring (30). The cylindrical sealing surface (12) is formed by grinding away the material of the ring (30) to expose a surface (26) of the elastomeric material which is contained in the cavity (50) in the ring (30). The plastic portions (24) of the cylindrical sealing surface (12) are defined by the ground surface (82) of the plastic ring (30). The elastomeric portions (26) of the cylindrical sealing surface (12) are defined by the exposed surfaces (26) of the elastomeric material.

Abstract: A ring expander and assembly machine, having a loading station, a spreading station and assembly station, is operable to expand a spiral retaining ring in place on a workpiece. Spiral retaining rings with locking tabs and slots are transported on a shuttle from the loading station to the spreading station, at which location, scraper blades and fulcrum cams cooperate to spread the ring and remove the tabs from the slots so that an expansible collar assembly can be used to expand the ring. A transporter moves the collar assembly with the ring to the assembly station where a stripper sleeve removes the ring from the collar assembly to the workpiece.