Belt retractor and method of controlling operation of an occupant restraint system

摘要

In a belt retractor the absolute angle of rotation of the belt reel is sensed by an incremental counter. The incremental counter is calibrated by sensing the angle of rotation of a control disc coupled to the belt reel by a reduction gear unit. The count of the incremental counter represents the absolute angle of rotation of the belt reel with high accuracy. Various components of a restraint system are controlled as a function of the thus measured absolute angle of rotation of the belt reel.