A webbing take-up device includes a spool that takes up webbing worn by an occupant, an input gear that is rotated by rotation force being transmitted, a spool gear that rotates the spool by being rotated, and a second clutch that is provided between the input gear and the spool gear, and that transmits rotation force of the input gear to the spool gear by being rotated by the input gear. The webbing take-up device further includes a sub clutch spring that is provided between the input gear and the second clutch, that transmits rotation force of the input gear to the second clutch when the input gear is rotated toward one side, and that shuts off transmission of rotation force of the input gear to the second clutch when the input gear is rotated toward another side.

A webbing take-up device includes a spool, a lock base that restricts pull-out direction rotation of the spool in a vehicle emergency, and a linear energy absorbing wire that deforms so as to permit pull-out direction rotation of the spool at or above a force limiter load when the lock base has restricted pull-out direction rotation of the spool. The webbing take-up device further includes a housing with which the energy absorbing wire engages along a radial direction inside face of the housing, and a winder section provided at a radial direction inside of the housing. The winder section is capable of rotating together as a unit with the spool, and takes up the energy absorbing wire by being rotated. Moreover, a wire guide and a lever are provided between the winder section and the housing. The wire guide and the lever pinch and deform the energy absorbing wire.

A webbing take-up device includes a spool, a lock gear that restricts pull-out direction rotation of the spool, a force limiter mechanism that permits pull-out direction rotation of the spool at or above a force limiter load, and a pawl that switches the force limiter load. The webbing take-up device further includes a cylinder section that includes a first cylindrical portion and a second cylindrical portion, a gas generator that supplies gas into the second cylindrical portion, and a piston section that is moved along the first cylindrical portion by an increase in pressure inside the second cylindrical portion and the first cylindrical portion so as to press and displace the pawl. An axial center of the second cylindrical portion is disposed offset with respect to an axial center of the first cylindrical portion, and an abutted portion that is abutted by the piston section is provided at a boundary between the first cylindrical portion and the second cylindrical portion.

A pretensioner includes a driving wheel and a power transmission unit. A spool is rotatably disposed in the driving wheel. The spool winds a webbing. The power transmission unit transmits power to the driving wheel. The power transmission unit includes a resin-made long body and a passage of the resin-made long body. The resin-made long body rotates the driving wheel. The passage is formed in an outer circumference of the driving wheel. The passage includes a wall surface, a cover member and a stopper. The wall surface is disposed on one side surface of the driving wheel. The cover member is fixed in the wall surface from the other side surface of the driving wheel. The stopper stops a tip portion of the resin-made long body which has rotated the driving wheel. The stopper is configured by a fastening member connecting the cover member and the wall surface.

A belt tensioner for a belt retractor having a load limiter includes a pivoted pinion (14) coupled to a belt reel, a drive unit and a load transmission element (20) moved by the drive unit. The load transmission element (20) engages in the pinion (14) so as to rotate the pinion in a tensioning direction A. The load transmission element (20) is designed so that in the rotational position adopted by the pinion (14) after being rotated by the load transmission element (20) a part (20b) of the load transmission element (20) engages in the pinion (14). A method of tensioning a seat belt by means of a belt tensioner and subsequent load limitation by means of a load limiter includes moving a load transmission element (20) by a drive unit in a first direction so that the load transmission element (20) engages in a pinion (14) coupled to a belt reel (12). The rotating the pinion (14) is rotated by the moved load transmission element (20) in a tensioning direction A. When the rotation of the pinion (14) is completed it is ensured that a part (20b) of the load transmission element (20) engages in the pinion (14).

A pretensioner includes a driving wheel and a power transmission unit. A spool is disposed to be rotatable in the driving wheel. The spool winds a webbing which restrains an occupant. The power transmission unit transmits power to the driving wheel during an emergency. The power transmission unit includes a resin-made long body, a pipe and a gas generator. The resin-made long body rotates the driving wheel. The pipe contains the resin-made long body. The gas generator supplies an operation gas into the pipe. The resin-made long body discharged from the pipe is configured to rotate the driving wheel while the resin-made long body is wound around the driving wheel.

An increase in structural complexity is suppressed in a webbing take-up device provided with a force limiter load switching mechanism and a pre-tensioner mechanism. The webbing take-up device includes a spool that takes up a webbing, a pre-tensioner mechanism that takes up the webbing onto the spool by rotating the spool in the take-up direction in a vehicle emergency, and a lock mechanism that restricts pull-out direction rotation of the spool in a vehicle emergency. The webbing take-up device further includes a force limiter mechanism that permits pull-out direction rotation of the spool at a force limiter load or greater when the lock mechanism has restricted pull-out direction rotation of the spool, and a force limiter load switching mechanism that switches a force limiter load value by being input with a portion of an actuation force that actuates the pre-tensioner mechanism.

A pawl member holding unit of a retractor for a seat belt includes: a cam protrusion which is provided at the other side of a torsion bar that is provided inside a spool, shares a rotation axis with the spool, and rotates together with the spool, the cam protrusion moving in accordance with the rotation of the torsion bar by an operation of a pretensioner; and a rotating member which rotates about a rotating shaft in accordance with the movement of the cam protrusion, and applies external force in a direction opposite to a direction in which a pawl member, which performs an automatic locking function, protrudes.

In a belt tensioner (10) for a seat belt comprising an elongate pressure reservoir (12), a piston (18) movably supported in the pressure reservoir (12) in the longitudinal direction to which piston pressurized fluid can be applied and which in this way can be moved in a tensioning direction (S), a mechanical thrust means (20) interacting with the piston, the thrust means interacting with a gearwheel (22) and driving the same in the case of restraint, and comprising a stop (24) on which the piston (18) abuts in the tensioning direction in a final position, it is provided that between the piston (18) and the thrust means (20) a spacer (30) in the form of a separate member is provided which is dimensioned such that in the final position of the piston (18) the thrust means (20) is urged past the stop (24) by said spacer. Furthermore there is provided a method of mounting a belt tensioner of this type.

A seatbelt retractor has: a holding plate arranged at a housing outer side and including a shaft receiving hole which rotatably supports a cylindrical shaped boss portion formed at a take-up drum side end of the driven body; and a restricting member arranged at take-up drum side of the holding plate to restrict movement of the boss portion in radial direction so that the boss portion projecting from the hole is positioned co-axial with the take-up drum. The boss portion which faces an inner peripheral surface of the hole includes a pair of radially projecting portions provided on both sides with reference to rotation axis direction projecting radially outward at full periphery of the boss portion. The pair of radially projecting portions project radially outward over the hole so at least a peripheral edge portion of the hole is inserted in clearance defined by the pair of radially projecting portions.