# US 2019/0170224 A1 · Hydraulic tensioning device for a chain drive > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170224 A1 - Document ID: US20190170224A1 - Status: Published application - Kind: A1 - Application number: 16/099,041 - Filed: 2017-05-03 - Published: 2019-06-06 - Earliest claimed: 2016-05-04 - Assignees: Schaeffler Technologies AG & Co. KG - Applicants: Schaeffler Technologies AG & Co. KG - Inventors: Rainer Fuhrmann - Web page: https://patentgrep.com/patent/US20190170224A1 ## CPC - F16H 7/08: Means for varying tension of belts, ropes or chains (pulleys of adjustable construction F16H55/52) - F16H 2007/0812: {Fluid pressure} - F16H 2007/0855: {comprising a clip member engaging with the rack teeth} - F16H 2007/0859: {Check valves} - F16H 2007/0878: {Disabling during transport} - F16H 2007/0891: {Linear path} - F16H: GEARING ## Abstract A hydraulic tensioning device for a chain drive, having a tensioning piston which is guided in a holder and which, on its outer circumferential surface, has locking grooves, an inner guide which projects into a cavity of the piston, and a locking element which has at least two annular sections and at least two radial extensions, wherein the locking element can be placed in engagement by the at least two annular sections with one of the locking grooves, and having a clamping stop and a sliding stop which are axially spaced apart from one another. To simplify the structural design, the holder has at least two axial extensions which extend in an axial direction between the clamping stop plane and the sliding stop plane, wherein the at least two axial extensions and the tensioning piston do not enclose the at least two radial extensions. ## Claims ### Claim 1 A hydraulic tensioning device for a chain drive, the hydraulic tensioning device comprising: a holder; a tensioning piston that is guided in the holder, the tensioning piston has locking grooves located on an outer peripheral surface thereof; an inner guide that extends into a hollow space of the piston; a locking element that has at least two annular sections and at least two radial extensions, the locking element is movable into engagement with one of the locking grooves with the at least two annular sections thereof; a clamping stop and a sliding stop that are spaced apart from each other in an axial direction on the holder, at least two axial extensions on the holder that extend in the axial direction between a clamping stop plane defined by the clamping stop and a sliding stop plane defined by the sliding stop that are arranged separated from each other in an area of the sliding stop plane, the at least two axial extensions of the holder and the tensioning piston do not enclose the at least two radial extensions of the locking element. ### Claim 2 (depends on 1) The hydraulic tensioning device according to claim 1, wherein two of the at least two axial extensions enclose a locking section in a peripheral direction, and one of the at least two annular sections is movable into engagement with one of the locking grooves in an area of the locking section. ### Claim 3 (depends on 2) The hydraulic tensioning device according to claim 2, wherein the locking element has exactly two of the annular sections and exactly two of the radial extensions and the holder has exactly two of the axial extensions that enclose two locking sections in a circumferential direction. ### Claim 4 (depends on 1) The hydraulic tensioning device according to claim 1, wherein the holder comprises a cylindrical hollow space, the tensioning piston is guided by the cylindrical hollow space or the holder comprises a cylindrical hollow space and a sleeve is inserted into the cylindrical hollow space, and the tensioning piston is guided by the sleeve. ### Claim 5 (depends on 1) The hydraulic tensioning device according to claim 1, wherein the at least two axial extensions each have a tapered section on both sides in a peripheral direction in an axial section between the clamping stop plane and the sliding stop plane, and the sliding stop is formed in the sliding stop plane. ### Claim 6 (depends on 1) The hydraulic tensioning device according to claim 1, wherein one of the at least two radial extensions defines a gap in the locking element. ### Claim 7 (depends on 6) The hydraulic tensioning device according to claim 6, wherein in an area of the gap of the locking element, two end sections of the locking element extend in a direction opposite each other, and partial sections of the two end sections are spaced apart from each other in a peripheral direction, extend outward in a radial direction, and are movable into contact with the sliding stop. ### Claim 8 (depends on 7) The hydraulic tensioning device according to claim 7, further comprising actuation sections that connect to the partial sections in a direction of the gap of the locking element, and the actuation sections extend in a direction of the opposite end section. ### Claim 9 (depends on 1) The hydraulic tensioning device according to claim 1, wherein one of the at least two radial extensions has a tapered section and includes a gap of the locking element, and the locking element into contact with the sliding stop in an area of the tapered section. ### Claim 10 (depends on 9) The hydraulic tensioning device according to claim 9, wherein the locking element includes a first end and a second end that enclose the gap, and in a peripheral direction a distance between the first end and the second end is greater than a distance between partial areas of the locking element that form the tapered section. ### Claim 11 A hydraulic tensioning device for a chain drive, the hydraulic tensioning device comprising: a holder; a tensioning piston guided in the holder, the tensioning piston including locking grooves on an outer peripheral surface thereof; an inner guide that extends into a hollow space of the piston; a locking element that has two annular sections and two radial extensions, the locking element is movable into engagement with one of the locking grooves with the two annular sections thereof; a clamping stop and a sliding stop that are spaced apart from each other in an axial direction on the holder; two axial extensions on the holder, the sliding stop being located on the axial extensions, the two axial extensions extend in the axial direction between a clamping stop plane defined by the clamping stop and a sliding stop plane defined by the sliding stop, the two axial extensions are arranged separated from each other on opposite sides of the tensioning piston in an area of the sliding stop plane, the two radial extensions of the locking element extend radially beyond the two axial extensions and the tensioning piston. ### Claim 12 (depends on 11) The hydraulic tensioning device according to claim 11, wherein the two axial extensions enclose a locking section in a peripheral direction, and one of the two annular sections is movable into engagement with one of the locking grooves in an area of the locking section. ### Claim 13 (depends on 11) The hydraulic tensioning device according to claim 11, wherein the tensioning piston is guided by a cylindrical hollow space in the holder or by a sleeve located in the cylindrical hollow space in the holder. ### Claim 14 (depends on 11) The hydraulic tensioning device according to claim 11, wherein the two axial extensions each have a tapered section on both sides in a peripheral direction in an axial section between the clamping stop plane and the sliding stop plane. ### Claim 15 (depends on 11) The hydraulic tensioning device according to claim 11, wherein one of the two radial extensions defines a gap in the locking element that allows movement of the two annular sections away from one another. ### Claim 16 (depends on 15) The hydraulic tensioning device according to claim 15, wherein in an area of the gap of the locking element, two end sections of the locking element extend in a direction opposite each other. ### Claim 17 (depends on 11) The hydraulic tensioning device according to claim 11, wherein each of the two radial extensions extends around a respective one of the axial extensions. ### Claim 18 (depends on 11) The hydraulic tensioning device according to claim 11, wherein the two radial extensions each have a tapered section, and the locking element is movable axially into contact with the sliding stop in an area of the tapered section.