# US 6,719,297 B2 · Piston ring, in particular for a piston of a vibration damper > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,719,297 B2 - Document ID: US6719297B2 - Status: Granted - Kind: B2 - Application number: 09/940,191 - Filed: 2001-08-27 - Published: 2002-04-18 - Granted: 2004-04-13 - Earliest claimed: 2000-08-25 - Assignees: Mannesmann Sachs AG - Inventors: Gerald Fenn; Hassan Asadi; Matthias Höhn; Peter Wirth - Web page: https://patentgrep.com/patent/US6719297B2 ## CPC - F16F 9/348: Throttling passages in the form of annular discs {or other plate-like elements which may or may not have a spring action}, operating in opposite directions {or singly, e.g. annular discs positioned on top of the valve or piston body (F16F9/341, F16F9/3415 take precedence)} - F16F 9/3214: {of pistons (F16F9/0227 and F16F9/36 take precedence; throttling passages in or on piston body F16F9/3405)} - F16F 9/368: {Sealings in pistons} - F16J 9/14: Joint-closures - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS ## Abstract Piston ring including a covering surface which covers a circumferential surface of a piston, and supporting segments having retaining surfaces which engage the upper and lower sides of the piston. The piston ring has a butt joint which enables the piston ring to be elastically deformable radially, the butt joint being designed at one end of the covering surface with at least one tongue which engages in a cutout in the other end of the covering surface. The tongue is designed with at least one retaining segment which runs in the circumferential direction and engages in a supporting manner in each case on the upper and lower side of the piston. ## Claims ### Claim 1 A piston assembly for a vibration damper, said piston assembly comprising a piston and a piston ring, said piston comprising an upper side, a lower side, and a circumferential surface between said upper side and said lower side, said piston ring comprising a circumferentially extending radially inward facing covering surface covering said circumferential surface of said piston, said covering surface having opposed ends, a pair of parallel radially inward extending supporting segments on the radially inward facing covering surface of said piston ring, said supporting segments having respective axially facing retaining surfaces engaging respective said upper and lower sides of said piston, a tongue formed at one of said ends of said covering surface, said tongue having a pair of circumferentially and radially inward extending retaining segments which engage respective said upper and lower sides of said piston, and a cutout formed at the other of said ends of said covering surface, said tongue engaging in said cutout to form a butt joint. ### Claim 2 (depends on 1) A piston assembly as in claim 1 wherein said tongue is movable circumferentially in said cutout so that said piston ring can expand radially. ### Claim 3 (depends on 1) A piston assembly as in claim 1 wherein said tongue comprises at least one centering web which aligns the tongue radially with respect to the cutout. ### Claim 4 (depends on 1) A piston assembly as in claim 1 wherein said piston ring is formed with a pair of parallel bearing segments flanking said cutout, said bearing segments fixing said other end of said piston ring axially with respect to said piston. ### Claim 5 (depends on 4) A piston assembly as in claim 4 wherein said bearing segments are supported axially on respective said retaining segments. ### Claim 6 (depends on 4) A piston assembly as in claim 4 wherein said tongue comprises a pair of centering webs formed on respective said retaining segments, said centering webs engaging respective said bearing segments to align said tongue radially with respect to said cutout. ### Claim 7 (depends on 1) A piston assembly as in claim 1 further comprising a clamping ring arranged inside of said piston ring, said clamping ring prestressing said piston ring radially outward. ### Claim 8 (depends on 7) A piston assembly as in claim 7 wherein said piston ring comprises a groove flanked by one of said supporting segments, said groove accommodating said clamping ring. ### Claim 9 (depends on 8) A piston assembly as in claim 8 further comprising a sealing lip parallel to said supporting segments, said groove being flanked by one of said supporting segments and said sealing lip. ### Claim 10 (depends on 9) A piston assembly as in claim 9 wherein said groove has a width and said clamping ring has a height, said width being greater than said height. ### Claim 11 A piston ring for fitting to a piston having an upper side, a lower side, and a circumferential surface therebetween, said piston ring comprising a circumferentially extending radially inward facing covering surface for covering said circumferential surface of said piston, said covering surface having opposed ends, a pair of parallel radially inward extending supporting segments on the radially inward facing covering surface of said piston ring, said supporting segments having respective axially facing retaining surfaces for engaging respective said upper and lower sides of said piston, a tongue formed at one of said ends of said covering surface, said tongue having a pair of radially inward extending retaining segments which engage respective said upper and lower sides of said piston, and a cutout formed at the other of said ends of said covering surface, said tongue engaging in said cutout to form a butt joint, said tongue being movable circumferentially in said cutout so that said piston ring can expand radially. ### Claim 12 (depends on 11) A piston ring as in claim 11 wherein said tongue comprises at least one centering web which aligns the tongue radially with respect to the cutout. ### Claim 13 (depends on 11) A piston ring as in claim 11 wherein said piston ring is formed with a pair of parallel bearing segments flanking said cutout, said bearing segments fixing said other end of said piston ring axially with respect to said piston. ### Claim 14 (depends on 13) A piston ring as in claim 13 wherein said bearing segments are supported axially on respective said retaining segments. ### Claim 15 (depends on 13) A piston ring as in claim 13 wherein said tongue comprises a pair of centering webs formed on respective said retaining segments, said centering webs engaging respective said bearing segments to align said tongue radially with respect to said cutout. ### Claim 16 (depends on 11) A piston ring as in claim 11 further comprising a clamping ring arranged inside of said piston ring, said clamping ring prestressing said piston ring radially outward. ### Claim 17 (depends on 16) A piston ring as in claim 16 wherein said piston ring comprises a groove flanked by one of said supporting segments, said groove accommodating said clamping ring. ### Claim 18 (depends on 17) A piston ring as in claim 17 further comprising a sealing lip parallel to said supporting segments, said groove being flanked by one of said supporting segments and said sealing lip. ### Claim 19 (depends on 18) A piston ring as in claim 18 wherein said groove has a width and said clamping ring has a height, said width being greater than said height.