Drive for safety belt pretensioner

The drive has a housing (14) with a gas generator (18) whose gas outlet opening opens into a pressure chamber in the housing and at least one drive shaft (34,36) rotatably mounted in the housing with at least one attached drive element (rigid arm (38,40)) subject to gas pressure from the generator, thereby rotating the drive shaft. The drive shaft is connected to a toothed drive wheel with a gap in its teeth near which a toothed wheel of a driven shaft is free to rotate.