Belt retractor unit for e.g. belt system utilized for occupant protection system in commercial aircraft, has torsional bar limiting force acting on belt strap during accident, where torsion characteristics of bar are changeable

摘要

The unit (10) has a belt strap (12) and a retractor module (14) with a spindle (18) that is rotatably supported at an axis (16). The belt strap is wound on the spindle. Force acting on the belt strap during accident is limited by a torsional bar (22) that is coupled with the spindle, where torsion characteristics of the torsional bar are changeable in multiple stages. The torsion bar has two torsion bar elements for changing the torsion bar characteristics. The torsion bar elements are coupled and decoupled with each other over an actuating unit (24). An independent claim is also included for a method for operating a belt retractor unit.