Rotary tightener is for a safety belt, particularly in a road vehicle, and involves a belt roller, of which a belt shaft carrying a belt wind when tightener drive is released rotates in winding direction of safety belt

摘要

The rotary tightener is for a safety belt, particularly in a road vehicle, and involves a belt roller, of which a belt shaft carrying a belt wind when the tightener drive is released rotates it in a winding direction of the safety belt. The belt shaft as tightener drive has recesses on its periphery to accommodate a drive wheel incorporating mass bodies. The mass bodies are housed in a tube issuing into the drive wheel and are accelerated in the tube by gas liberated by a gas generator at the end of the tube. A tube section acting as a pre-volume on the first mass bodies is provided. The tube section (14) forming the pre-volume (15) has a smaller cross-section than the storage section (12) of the tube (10) housing the mass bodies.