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.

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.

A seatbelt pretensioning retractor assembly for use in a passenger 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 a proximal end portion of the polymer rod. A piston-safety valve member is disposed between the gas generator and the stopper and is configured to allow gas from the gas generator to pass therethrough when the gas is at or above a predetermined pressure.

A seatbelt pretensioning retractor assembly for use in a passenger 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 a proximal end portion of the polymer rod. A piston-safety valve member is disposed between the gas generator and the stopper and is configured to allow gas from the gas generator to pass therethrough when the gas is at or above a predetermined pressure.

A pretensioner for introducing a webbing wound in a spool by explosive power obtained by exploding gunpowder when an impact is applied from the outside, the pretensioner includes: a hollow cylinder having one side surface for inserting a portion of a pinion connected to the spool; a micro gas generator (MGG) mounted in an upper end portion of the cylinder and for transferring explosive power into the cylinder while gunpowder provided at the inside explodes when an impact is applied from the outside; a rack mounted in a length direction at the inside of the cylinder and having one end portion disposed toward the MGG and having the other end portion disposed opposite to the pinion and having gear teeth provided in one side surface separated not to engage with the pinion before receiving explosive power from the MGG; and a roller for receiving explosive power from the MGG and rotatably mounted at the other side surface opposite to one side surface of the cylinder in which a portion of the pinion is inserted so that the gear teeth of the rack engage with the pinion when the rack falls toward a lower end portion of the cylinder and for guiding the separated rack to move toward the pinion.

In a pretensioner mechanism of a webbing take-up device, a sealing member seals a communicating hole of a piston. When a force limiter mechanism is operated and rotating of a spool in a pull-out direction is allowed, the piston is moved to an upper side in a state in which the sealing member is pressed and contacted against a cylinder. As a result, the sealing member is turned and the sealing of the communicating hole by the sealing member is released. In consequence, a number of components may be reduced and assembly characteristics of the pretensioner mechanism may be improved.