Provided are a pretensioner, a retractor, and a seat belt device that can effectively reduce kinetic energy of an injected power transmission member. A power transmission unit includes a power transmission member that is engageable with external teeth of the ring gear, a pipe that contains the power transmission member, a gas generator that is disposed at an end of the pipe, a piston that receives gas generated from the gas generator to press the power transmission member, a first stopper that is disposed on an upstream side of the power transmission member, a second stopper that is disposed between the power transmission member and the piston, and a pretensioner cover that defines a passage for the power transmission member.

A belt retractor (10) for a seat belt comprising a belt reel (20), a belt tensioner (44) adapted to drive the belt reel (20) in a winding direction and an extension limiter (16) adapted to restrict the number of revolutions of the belt reel (20) in an unwinding direction in the activated state. The extension limiter (16) is communicated with the belt tensioner (44) so that the extension limiter (16) can only be activated after the belt tensioner (44) has been activated.

A belt retractor for a motor vehicle seat belt device, with a rotatably mounted belt reel onto which a seat belt is wound, and a belt tensioner with a drive wheel (1), which drives the belt reel in the event of an activation. A positively controlled tensioner coupling transfers the drive movement from the drive wheel (1) onto the belt reel. At least one coupling pawl (2,3) mounted on the drive wheel (1) and which is moved into and out of engagement with a toothing (20) rotationally fixed in relation to the belt reel to establish and disconnect a rotational connection of the drive wheel (1) with the belt reel. A friction ring (4) has a control arm (11) coupled with the coupling pawl (2,3), wherein in the event of an activation of the belt tensioner, the friction ring (4) performs a relative movement to the drive wheel (1) by frictional forces and, controls via the control arm (11) the movement of the coupling pawl (2,3) into engagement and disengagement with the toothing (20). The friction ring (4) and/or the coupling pawl (2,3) has a blocking contour (12), positioned such that the coupling pawl (2,3) abuts thereon after the disengaging movement out of the toothing (20) and is blocked in the direction of a repeated engagement movement into the toothing (20).

Provided are a pretensioner, a retractor, and a seat belt device that can achieve weight reduction of a device by improving slidability of a power transmission member used for the pretensioner. A pretensioner includes a drive wheel for rotating the spool, and a power transmission unit for transmitting power to the drive wheel in an emergency. The power transmission unit includes a power transmission member for rotating the drive wheel, a pipe that contains the power transmission member, a gas generator for supplying a working gas into the pipe, and a housing that defines a passage for the power transmission member on an outer periphery of the drive wheel. The housing has a sliding member that is disposed at an outlet part of the pipe and that reduces frictional force between the housing and the power transmission member.

In a vehicle emergency, a spool of a webbing take-up device is rotated in a pull-out direction such that a main lock is displaced toward a rotation-radial direction outside of the spool and engages with a clutch gear configuring a first rotation body. Rotation of the spool in the pull-out direction is thus restricted. Also in a vehicle emergency, the first rotation body is rotated in a take-up direction of the spool such that the main lock engages with the first rotation body, and rotation force of the first rotation body is transmitted to the spool through the main lock and the spool is rotated in the take-up direction.

An assembly includes a housing. The assembly includes a spool rotatable relative to the housing. The assembly includes a cable fixed to the spool. The assembly includes a passenger restraint fixed to the cable. The assembly includes a pyrotechnic device fixed relative to the housing and designed to rotate the spool relative to the housing. The assembly includes a ratchet-and-pawl mechanism between the housing and the spool.

The present invention relates to an ejector clutch (1) for a belt tensioner, comprising a first shaft (10), a second shaft (20), and a coupling part (30), wherein the coupling part (30) is arranged between the first shaft (10) and the second shaft (20) in a longitudinal axis (X) defining an axial direction, wherein the coupling part (30) has at least one clutch finger (40), which engages in a first recess (15) of the first shaft (10) for transmitting a torque (M) and, when a torque (M2) to be transmitted is exceeded, said clutch finger is displaced, against a spring force in the axial direction, from the first recess (15) of the first shaft (10) into a second recess (25) of the second shaft (20). The invention further relates to a belt tensioner with an ejector clutch (1).

The invention discloses a belt retractor comprising a frame (10), a belt reel (12) which is arranged rotatably in the frame (10) and can receive a seat belt (14), at least one load limiter (16) which enables the belt reel (12), when it overcomes a braking torque provided by the load limiter (16), to rotate relative to the frame (10) so as to release seat belt (14), and a switchable clutch (26) including a switching cage (22) and coupling elements (24), wherein the switching cage (22) can be shifted by means of an actor (28) from an open position in which the coupling elements (24) are maintained disengaged from the belt reel (12) to a closed position in which the coupling elements (24) engage the belt reel (12). In order to achieve a compact design, the belt retractor includes an actuator (38) which is coupled to the actor (28) and a freewheel (40) which couples the switching cage (22) to the actuator (38) so that the actuator (38) can shift the switching cage (22) from the open position to the closed position.

A webbing take-up device is provided with a spool, a first rotor and a second rotor. A webbing to be applied to a vehicle occupant is taken up onto the spool by the spool rotating in a take-up direction. The first rotor is provided to be rotatable together with the spool, includes first engaging teeth with which a moving member that is moved engages, and is rotated when the moving member that is moved engages with the first engaging teeth. The second rotor is provided to be rotatable together with the spool, includes second engaging teeth with which the moving member that is moved engages, and is rotated when the moving member that is moved engages with the second engaging teeth. The second engaging teeth are disposed so as to overlap with the first engaging teeth in a rotation circumference direction of the first rotor.

An engagement and disengagement device used in a seat belt retractor includes a first rotating member and a second rotating member configured to be coaxial, and a transmission member disposed between the first and second rotating members. The first rotating member defines an engagement portion on a radial inner surface thereof, and the distance from the engagement portion to an axis of rotation gradually increases in a first direction of rotation. The transmission member can rotate between an engagement position and a non-engagement position relative to the first rotating member.