Abstract: A housing (2) for mounting a gas generatot (7) in a pyrotechnic pretensioner, the housing comprising a hollow container for supporting the gas generator, the container having an opening through which the gas generator (7) may be inserted and having a tapered end section (20) arranged to be adjacent and to co-operate with a gas outlet end of the gas generator to provide a seal around the gas outlet, and the hpusing having a cover (8) for closing the container opening, the cover having a tapered wedge member (22) extending into the container in use at the opposite end to the tapered end section (20) to urge the gas generator (7) towards the tapered end section (20) of the container, in a close fit manner. The wedge(22) is preferably integral with the housing cover (8). This housing makes fitting of the gas generator easier and improves the seal between it and the pretensioner thus improving performance.

Abstract: A pretensioner for a vehicle safety restraint having a cylindrical hollow tube and a piston connected via a cable to a part of the vehicle safety restraint for tightening the safety restraint in the event of a crash. The piston having a gas generator with gas vents directed with a component in the opposite direction to that of the piston movement for belt tightening. The piston also having locks and seals, the locks being operable only against the belt loosening direction, and wherein the gas generator is positioned forward of the locking mechanism in the direction of piston movement for belt tightening.A more compact, cost effective pretensioner is possible.