Abstract: A piston ring for use in hydraulic cylinder cushions wherein advantage is made of the typical imperfect seal characteristics of a conventional metallic piston ring to effect a cushion exhaust fluid metering action near the piston stroke end; the piston ring then uniquely allowing major fluid bypass in the reverse stroke or input fluid pressure direction for instant, full reverse stroke piston velocity response wherein the invention includes a piston ring having a notched pattern in one ring edge surface, which surface is adjacent a piston ring groove side wall, thereby eliminating the prior art need for added secondary flow circuits to accomplish the same instant out of cushion full piston velocity result.

Abstract: Apparatus is disclosed for an improved hydraulic piston and cylinder design wherein grooves in the piston surface create a dashpot effect at the respective ends of piston stroke and assist hydraulic oil porting into the cylinder for improved response during stroke reversal, where the piston at least partially covers the cylinder oil flow port.

Abstract: The piston of a hydraulic cylinder is provided with a corrugated running surface composed of angularly disposed ribs and valleys therebetween, the ribs bearing against the relatively smooth bore of the tubular casing in which the piston reciprocates. Whereas the ribs on the piston provide a corrugated running surface bearing against the bore, the cylinder head, in which the piston rod is journaled, is formed with a similarly corrugated running surface.

Abstract: A piston rod has a shoulder longitudinally spaced from one end thereof so as to form a stem of reduced cross section for engagement into a piston within a hydraulic cylinder. The stem includes a threaded shank extending from its free end to a male cylindrical pilot spaced from the shoulder by an annular stress-relieving groove. A piston has a threaded central bore portion and counterbore portions at each end, wherein one counterbore portion functions as a female pilot for receiving therein the male pilot in an interference fit relationship, and the other counterbore receives therein a plastic sealing ring which engages the threaded shank of the stem in sealing and centering relationship.