Abstract: A three-part oil scraper ring includes an upper scraper ring (24), a lower scraper ring (26), wherein the scraper rings (24, 26) are held at a distance by an expander spring (34) and pressed radially outwards. The upper scraper ring (24) has a ring body (4) having an upper flank (6), a lower flank (8), a ring inner surface (10) and a ring outer surface (12) which has a ring outer contour (14) in cross-section in axial direction (A). The ring body (4) has a height H which, when viewed in axial direction (A), corresponds to the greatest distance of the upper flank (6) from the lower flank (8). The ring outer contour (14) forms a running surface (16) which has a radius of curvature R which is smaller than the height H of the upper scraper ring (24) by a factor between 1.5 to 6.

Abstract: An apparatus adapted for use in a gas turbine engine includes a first circumferential member and a second circumferential member. The first circumferential member includes an end portion that defines a recess and includes a first seal surface. The second circumferential member includes an end portion that includes a second seal surface. The end portion of the second circumferential member is configured to be at least partially disposed in the recess of the first circumferential member to collectively form at least a portion of a circumferential assembly of a gas turbine. The first seal surface of the first circumferential member is forms a first seal with a seal member and the second seal surface of the second circumferential member is forms a second seal with the seal member when the end portion of the second circumferential member is disposed in the recess of the first circumferential member.

Abstract: Gastight piston ring arrangements require an active seal in the axial and radial directions in order to be able to obtain a high sealing effect. At the same time, the piston ring arrangement, while maintaining the sealing effect both on the sealing surface and between the parts of the piston ring arrangement, must be capable of readjustment in the event of continued wear. For a segmented piston ring comprising piston ring segments 2 having stepped ends 5, 6, this is achieved according to the invention by the fact that on at least one piston ring segment 2, on the radially inner peripheral surface 9 over a part of the width of the piston ring segment 2, a radial step 4 is provided, and a single-cut sealing ring 3 is provided, which bears radially against the inside of the peripheral surface 9 of the piston ring segments 2, and on the sealing ring 3 an axial recess 10, 12 is provided, which cooperates with the radial step 4 of the piston ring segment 2.

Abstract: A variable oil ring compression mechanism provides for real-time cyclic variation of piston ring tension in an operating internal combustion engine. A cam is situated in the gap of a piston oil control ring, the cam affixed to a shaft secured to a pivot plate positioned within the body of the piston, wherein the pivot plate is adapted to oscillate in a follower-style rocking motion responsive to the rotary movement of a connecting rod boss positioned in close proximity with the plate. In a preferred form, the cam is situated between ends of an expander ring positioned between oil scrapper rails in the bottom groove of the piston.