# US 7,744,126 B2 · Tensioning device for seatbelts with an olive-shaped piston > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,126 B2 - Document ID: US7744126B2 - Status: Granted - Kind: B2 - Application number: 12/090,605 - Filed: 2006-10-10 - Published: 2008-11-13 - Granted: 2010-06-29 - Earliest claimed: 2005-10-18 - Assignees: Autoliv Development AB - Inventors: Michael Dürrer; Jens Ehlers; Maren Leyffer - Web page: https://patentgrep.com/patent/US7744126B2 ## CPC - F15B 15/125: {of the curved-cylinder type} - B60R 22/1952: {Transmission of tensioning power by cable; Return motion locking means therefor} - F15B 15/19: Pyrotechnical actuators - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR ## Abstract A tensioning device for a seatbelt system in motor vehicles with a driving arrangement that comprises a tube having at least one tube section bent with a radius of curvature, and a piston guided movably in said tube, whereby the piston is connected via a driving cable to the part of the seatbelt system which carries out the tensioning movement, and whereby the piston can be moved in a longitudinal movement through the tube by means of a pyrotechnic drive, and the driving cable is fixed to the piston by means of a holding part held by the piston. The piston (14) is configured in the form of an olive with a larger radius in the longitudinal direction of the tube (10) than the effective radius in the transverse direction of the tube (10) and is provided with a bore (15) for passing through the driving cable (20) that is held in a compression sleeve (16) fixed on the side of the piston (14) that points in the direction of movement of the piston (14). ## Claims ### Claim 1 A tensioning device for a seatbelt system in motor vehicles with a driving arrangement that comprises a tube having at least one tube section bent with a radius of curvature, and a piston guided movably in the tube, whereby the piston is connected via a driving cable to a part of the seatbelt system which carries out the tensioning movement, and whereby the piston is movable for longitudinal movement through the tube by means of a pyrotechnic drive, and the driving cable is fixed to the piston by a holding part held by the piston, the piston is configured having a generally ellipsoidal form with a larger radius in the longitudinal direction of the tube than the effective radius in the transverse direction of the tube and is provided with a bore for passing through the driving cable that is held in a compression sleeve fixed on the side of the piston that faces in the direction of movement of the piston. ### Claim 2 (depends on 1) The tensioning device according to claim 1, wherein the compression sleeve is configured with a tube-shaped section enclosing the driving cable and an adjacent disk-like projecting piece adjacent to the compression sleeve, whereby the tube-shaped section of the compression sleeve extends into the bore of the piston and the disk-like projecting piece abuts against the front side of the piston. ### Claim 3 (depends on 2) The tensioning device according to claim 2, wherein the tube-shaped section of the compression sleeve abuts against a shoulder configured in the bore of the piston with the front side of the shoulder when the piston driven for movement in the tube and a compression force is applied to the piston, and the tube-shaped section does not abut against the shoulder when no compression force is applied to the piston. ### Claim 4 (depends on 1) A tensioning device according to claim 1, wherein the piston features a circumferential groove whose exterior circumferential boundaries are formed to protrude outward, and form two spaced sealing beads forming a front sealing bead and a rear sealing bead with associated sealing surfaces. ### Claim 5 (depends on 4) The tensioning device according to claim 4, the area of the piston adjacent to the front sealing bead in the direction of movement of the piston is configured as a truncated cone in the direction of the compression sleeve. ### Claim 6 (depends on 5) The tensioning device according to claim 5, wherein the truncated cone area of the piston is configured such that it forms an enlarged contact surface for the disk-like projecting piece of the compression sleeve at the front end of the sleeve. ### Claim 7 (depends on 4) The tensioning device according to claim 4, wherein the area of the piston adjacent to the rear sealing bead (23) in the direction of movement of the piston (14) is configured as a truncated cone. ### Claim 8 (depends on 4) The tensioning device according to claim 4, wherein the area of the piston adjacent to the rear sealing bead in the direction of the piston is configured as a cylinder. ### Claim 9 (depends on 1) The tensioning device according to claim 1, wherein on the side of the piston facing away from the compression sleeve, a guiding part abutting against the front side of the piston is arranged and mounted on the driving cable. ### Claim 10 (depends on 9) The tensioning device according to claim 9, wherein the guiding part is configured as a sphere. ### Claim 11 (depends on 9) The tensioning device according to claim 9, wherein the guiding part is configured as a cylindrical guide piston and on its contact surface facing the piston it has a cap for positive-abutment with the piston surface. ### Claim 12 (depends on 11) The tensioning device according to claim 11, wherein the cylindrical guide piston is pot-shaped and open on the side opposite the direction of movement of the piston. ### Claim 13 (depends on 12) The tensioning device according to claim 12, wherein the external borders of the cavity of the pot-shaped guide piston have an inward bevel. ### Claim 14 (depends on 9) The tensioning device according to claim 9, wherein the guiding part is made of metal. ### Claim 15 (depends on 9) The tensioning device according to claim 9, wherein the guiding part is made of a plastic material.