Abstract: An anti-extrusion ring for supporting a sealing unit of a piston or rod system is disclosed. The anti-extrusion ring is split across two surfaces for ease of installation and the split is configured to effectively prevent extrusion at either split surface and eliminate nibbling of the sealing components.

Abstract: A cylindrical seal apparatus according to one embodiment includes a split spring ring and a split seal ring supported in a groove for example defined in a piston. The split spring ring in a tensioning condition presses against a tapered annular inner surface of the split seal ring to create a radial pre-load and an axial pre-load to the slit seal ring to establish a primary sealing contact between the seal ring and a cylinder, and a second sealing condition between the seal ring and a lower-pressure side of the groove, before the working fluid pressure is built up.

Abstract: A piston ring with an upper part ring having an upper ring surface and with a lower part ring having a lower ring surface, and with a ring spring which is arranged between the part rings and acts with spring force upon these radially outward, characterized in that each of the two part rings has, on its circular-ring surface in each case facing the other part ring, a plurality of elevations arranged so as to be separated from one another by depression regions, with plateau surfaces which are parallel to the ring surfaces and are flat-planar or descend and which have in each case, the ring axis of the respective part ring, toward an inner-flank indentation which emanates, oriented parallel to the ring axis, from the plateau surfaces and runs out toward said spring axis, in each case parallel to the upper and the lower ring surface, and which has a quarter-circle-shaped cross section, the radius rv of said inner-flank indentation being 1 to 10% larger than the outer radius of the circle cross section of the comm

Abstract: In a combined oil ring having a spacer expander to be installed between a pair of upper and lower side rails, a plurality of axially protruding inner peripheral protruding portions are formed on the inner peripheral side of the spacer expander along its peripheral direction. The inner peripheral protruding portions press the inner peripheral surface of the side rails. On the outer peripheral side of the spacer expander, a plurality of slits are formed, and a plurality of connecting portions are located in the peripheral direction isolated by the slits. On the plurality of connecting portions, axially protruding outer peripheral protruding portions are formed.

Abstract: A piston includes a circumferential groove having a dynamic split seal ring having a flat axially facing surface, a static seal ring having a flat axially facing surface abutting the flat surface of the dynamic seal ring, and a spring mounted within the groove. The spring exerts an axial force on the static seal ring that serves to distribute the axial load with a static seal over the dynamic split seal, thereby preventing shuttling of the split seal within the groove and restricting the leak path of the seal. Preferably, the static seal ring is a polymer and can be an L-ring, a load ring with a flange that abuts the piston body, or flanged designs. In addition, a load ring can be fitted between the L-ring and the spring. The split seal ring has at least one radial spring mounted within the seal ring to create a radial force on the split seal ring. The piston can also include a sleeve that mounts to the piston body, the sleeve forming a wall of the groove.

Abstract: An improved thin 3-piece oil ring 1 of an axial width not greater than 2 mm, is provided that has a corrugated spacer expander 2 of a circumferentially successive, substantially U-shaped configuration, and circular, upper and lower side rails 3, 4 holding the spacer expander 2 therebetween. The spacer expander 2 has circumferentially spaced outer crowns 5 and circumferentially spaced inner crowns 6; each of the outer crowns 5 being connected with next adjacent ones of the inner crowns 6 on opposite sides thereof by a pair of connecting members 11. The spacer expander 2 has both of the most-end portions thereof extended radially outwardly from the most-end one of the inner crowns 6 thereof forming abutting members 15, 16 for abutting each other at the point of force P.