Gas generator

The gas generator (10) has an outer casing with holes to allow the escape of gas to inflate the airbag. A pressure container (12) is closed by a bursting disk (16). When the disk bursts the gas presses against the closed end (28) of a cylindrical valve element (24). The valve element fits inside an outlet chamber (14) and the closed end is pushed in by the gas pressure so that it progressively uncovers ports in the thick sidewalls (18) of the outlet chamber.