A power transmission member including a base resin that has a water absorption characteristic that a water absorption rate is 1% or less when Method 1 of ISO 62 (a method for measuring a weight increasing rate after being immersed in water at 23? C. for 24 hours) is used and an elastomer that imparts mechanical characteristics to the power transmission member 32a, in which as the mechanical characteristics, tensile yield stress (ISO 527) is 40 to 54 MPa, tensile fracture strain (ISO 527) is 50% or more, tensile elastic modulus (ISO 527) is 1200 to 1900 MPa, bending elastic modulus (ISO 178) is 1100 to 1700 MPa, and unnotched Charpy impact strength (ISO 179) is no fracture at ?30? C. or higher.

A seatbelt tensioner for a seat belt retractor, having a pipe (1) with a tensioner drive wheel. A pyrotechnical gas generator (10), a piston (3), and at least one mass body (4) in the pipe (1), wherein the at least one mass body (4) is drivable by the pressure generable by the gas generator (10) and acting on the piston (3) between the gas generator (10) and a mass body (4), and which can be made to mesh in a force-transmitting manner with the tensioner drive wheel, thus driving a belt shaft of the seat belt retractor in a belt tensioning direction. The pipe (1) has a receiving section (5) with a first inner diameter (2), in which the piston (3) in its initial state is arranged with an initial-state outer diameter (8) prior to the ignition of the gas generator (10). The pipe (1) has a guide section (6) which adjoins the receiving section (5) and which has a second inner diameter (7). The second inner diameter (7) is smaller than the first inner diameter (2) and smaller than the initial-state outer diameter (8) of the piston (3).

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 webbing take-up device has a pretensioner mechanism that rotates a spool in a take-up direction owing to a micro-gas generator being operated at a time of an emergency of a vehicle. A micro-gas generator mounting portion of the pretensioner mechanism is formed in a shape of a tube into which the micro-gas generator is inserted. The micro-gas generator mounting portion has recessed portions, whose micro-gas generator sides are open, and convex portions that are formed along the recessed portions, and that are formed in shapes that are convex toward the micro-gas generator side, and on which a portion of the micro-gas generator is anchored.

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 belt pretensioner has a base member. The base member has an axial cavity within. An actuating member is hollow and fits within the axial cavity of the base member. The hollow actuating member telescopically slides within the axial cavity and an initiator fits within the hollow portion of the actuating member. In a critical situation such as a crash, the initiator is triggered and the expanding gasses move the actuating member. The actuating member is connected to seat belt webbing and this movement provides the necessary pretensioning of the seatbelt. In some embodiments, a locking means is used to prevent the belt pretensioner from loosening once triggered. One embodiment is provided for use with a child seat. A transversely mounted belt pretensioner embedment is also disclosed.

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 pretensioner and a seat belt device are provided. A pretensioner includes a wire connected to webbing that restrains an occupant, a piston disposed to the wire, a cylinder that slidably accommodates the piston, a gas generator that applies driving force to the piston, and a housing that integrally connects the cylinder and the gas generator. The housing includes an insertion hole that guides the wire, a communication part that is communicated with the cylinder and the insertion hole, and a gas-supply port that supplies gas generated by the gas generator to the communication part. The pretensioner includes a wire guide disposed at a boundary portion of the insertion hole and the communication part, and a holding member that is inserted into the communication part and locked to the gas-supply port, thereby to position the wire guide.

The invention relates to a belt retractor comprising a frame (10), a belt reel (12) rotatably arranged within the frame, a blocking mechanism (18) by which the belt reel (12) can be blocked within the frame (10), and a load limiter (14) which is detachably coupled to the belt reel (12), characterized in that for coupling the load limiter (14) at least one load-transmitting bar (28) is used which is arranged at the belt reel (12) and is retained in a coupling position by a support ring (32), wherein the support ring (32) can be moved from a supporting position to a release position by means of an actor (70).

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.