A winding drum used for winding a safety belt extends in the axial direction and is rotatably supported in a frame of a retractor. A gear mechanism is installed at one side of the winding drum through a force limiting mechanism and comprises a stop wheel and a ball gear which are riveted and fixedly connected in the axial direction. The stop wheel is rotatably installed on the frame, and the ball gear comprises a penetrating shaft hole. The force limiting mechanism is inserted into the shaft hole in the axial direction and both ends of the force limiting mechanism are respectively connected with the winding drum and the gear mechanism to prevent passengers from being excessively restrained by realizing the force limiting function. The gear mechanism and the force limiting mechanism are directly assembled to the winding drum, with simple steps and few independent components.

A belt tensioner (10) for a seatbelt system comprises a tensioner tube (20) having an open outlet end and a force transmission element (22) which is guided in the tensioner tube (20) and which leaves the tensioner tube (20) via the open outlet end, a gas generator (18) providing compressed gas for displacing the force transmission element (22) within the tensioner tube (20) as well as a drive wheel (16) rotated by the force transmission element (22) leaving the tensioner tube (20). There is provided a guiding component (24) surrounding the drive wheel (16) into which guiding component the force transmission element (22) enters upon leaving the tensioner tube (20). At the guiding component (24) an energy-dissipating structure (50) is provided which the force transmission element (22) contacts when it has at least substantially completely left the tensioner tube (20).

A seatbelt pretensioning retractor assembly for use in a vehicle is provided. The pretensioning assembly includes a tube in fluid communication with a gas generator and a driving element disposed therein that travels in a first direction in response to actuation of the gas generator. The driving element includes a polymer rod. A stopper is coupled to an end portion of the polymer rod. In one example, a seal member disposed between the gas generator and the stopper includes a head section and a skirt section. In another example, the tube has an opening that is adjacent to an exit to facilitate venting gas from the gas generator.

A seat belt retractor comprises a rotatable spool on which seat belt webbing is wound. The spool is rotatable in a webbing withdrawal direction and an opposite webbing retraction direction. The seat belt retractor also comprises a pretensioner actuatable to rotate the spool in the webbing retraction direction and a load-limiting system to limit a load applied to a vehicle occupant by the seat belt webbing. The load-limiting system includes a torsion bar mounted such that the torsion bar is twisted when a load in excess of a predetermined load is applied to the spool in the webbing withdrawal direction by the seat belt webbing. The bad-limiting system also includes a stop assembly actuatable to limit rotation of the spool in the webbing withdrawal direction to a predetermined number of rotations while the torsion bar is being twisted. The stop assembly is actuated upon actuation of the pretensioner.

In a vehicle emergency, rotation of a lock base in a pull-out direction opposite to a take-up direction is restricted. A first pinion-configuring portion formed at an outer circumferential portion of the lock base configures one width direction side of a pinion section that is rotated in the take-up direction by a rack that moves due to fluid pressure in a vehicle emergency. A coupling member disposed between the lock base and the torsion shaft is fixed to the lock base and to a torsion shaft. A second pinion-configuring portion that configures a width direction other side of the pinion section is formed alongside the first pinion-configuring portion at an outer circumferential portion of the coupling member.

A pretensioner includes a drive wheel provided with a plurality of engaging teeth for rotating a spool, the spool for winding up a webbing for fastening a passenger; and an elongated resin component that transmits power to the drive wheel during an emergency, wherein the plurality of teeth is positioned such that, when one engaging tooth is caused to contact a tip of the elongated resin component in an approximately planer manner, another engaging tooth adjacent to the one engaging tooth in a direction opposite to a rotation direction can contact a side surface of the elongated resin component.

In a belt retractor (10) having a belt tensioner (16) and a force-limiting device, the belt tensioner (16) includes a pivoted pinion gear (24) associated with a belt reel (14), a drive unit (18) and an oblong force-transmitting element (22) movable by the drive unit (18) supported at least partly in a tubular portion (21) and adapted to be engaged in the pinion gear (24) so as to rotate the pinion gear (24) in a tensioning direction (A). The force-transmitting element (22) includes a bending portion (30) which is provided at the rear end of the force-transmitting element (22) viewed in the tensioning direction and which is designed to be pressure-resistant in the longitudinal direction (L) of the force-transmitting element (22) but to be flexible in a direction perpendicular to the longitudinal direction (L).

A seat belt retractor comprises a rotatable spool on which seat belt webbing is wound. The spool is rotatable in a webbing withdrawal direction and an opposite webbing retraction direction. The seat belt retractor also comprises a pretensioner actuatable to rotate the spool in the webbing retraction direction and a load-limiting system to limit a load applied to a vehicle occupant by the seat belt webbing. The load-limiting system includes a torsion bar mounted such that the torsion bar is twisted when a load in excess of a predetermined load is applied to the spool in the webbing withdrawal direction by the seat belt webbing. The bad-limiting system also includes a stop assembly actuatable to limit rotation of the spool in the webbing withdrawal direction to a predetermined number of rotations while the torsion bar is being twisted. The stop assembly is actuated upon actuation of the pretensioner.

A tensioner tube (18) for guiding a load transmission element (20) for a belt tensioner comprises an exit end (32) and a tube section (34) adjacent to the exit end (32), the tube section (34) being configured and arranged so that the longitudinal axis (L) of the tube section (34) is substantially tangent to the drive gear (14), wherein an elongate projection (36) protruding into the interior of the tube, the longitudinal axis (I) of which is inclined in relation to the longitudinal axis (L) of the tube section (34), is formed in the tube section (34) adjacent to the exit end (32). A belt tensioner for a seat belt system comprises a pyrotechnically movable load transmission element (20) and a drive gear (14) which can be driven by the movable load transmission element (20). The load transmission element (20) is guided in a tensioner tube (18) of the above-mentioned type.

A drive wheel for a belt tensioner is adapted to be coupled to a belt reel and includes an external tooth system including plural teeth distributed along the circumference. The teeth are inclined in a first circumferential direction and/or the teeth have at least one end face facing away from the central axis of the drive wheel and being inclined in a first circumferential direction and/or the clearances between neighboring teeth are not symmetrical with respect to planes defined by radial and axial directions. The teeth have no symmetry with respect to planes extending tangentially relative to the circumferential direction.