Patent ID: 8459584

Claim:
A seat belt tensioner for a seat belt system of the type having a seat belt and a seat belt retractor with a spool rotatable about a longitudinal axis, the seat belt tensioner comprising: a tensioner drive pinion connected to the seat belt retractor to be rotatable with the spool about the longitudinal axis; a tube; a pyrotechnic gas generator located at an end of the tube; and several mass bodies drivable by pressure generated by the gas generator, the mass bodies being engageable with the tensioner drive pinion in a force transmitting manner to drive the seat belt retractor spool in a winding direction, the tube having a first section with a central axis extending past the tensioner drive pinion and perpendicular to the longitudinal axis, and the tube having a second section with a central axis tangentially approaching the tensioner drive pinion, the central axis of the first section and the central axis of the second section being arranged in one plane on opposite sides of the drive pinion and connected to each other via a third section of the tube, the third section having a curved central axis extending outward and transverse from the plane, and the first section, the second section and the third section defining a free space having dimensions suitable to accommodate at least one of the mass bodies emerging from the tensioner drive pinion.