Load Limiting Seat Belt Retractor With Spiral Turn Limiter

摘要

A motor vehicle seat belt retractor having load limiting features for controlling seat belt restraint loads for a retractor having a spool for storing belt webbing and rotatable with respect to a retractor frame, and a locking mechanism for locking the spool to provide vehicle occupant restraint. A load limiting element coupled with the spool limits restraint loading of the seat belt webbing upon locking of the spool. A rotational displacement limiting mechanism limits the displacement of the load limiting element, the limiting mechanism having a cam forming a spiral flight rotatable with the load limiting element and a cam follower engaging the spiral flight. The cam and the cam follower interengage to reach an end position preventing further relative angular displacement beyond a predetermined angular displacement of the load limiting element. Embodiments provide various configurations for the cam and cam follower elements.

主权项

1. A motor vehicle seat belt retractor having load limiting features for controlling restraint load acting on seat belt webbing stored on the retractor, the retractor of a type having a spool rotatable with respect to a retractor frame, the spool storing the seat belt webbing wrapped thereon, and a locking mechanism for selectively locking the spool to provide vehicle occupant restraint, the retractor comprising:
a load limiting element coupled with the spool, the load limiting element limiting restraint loading of the seat belt webbing upon locking of the locking mechanism, and a rotational displacement limiting mechanism for limiting the displacement of the load limiting element, the limiting mechanism having a cam forming a spiral flight rotatable with a portion of the load limiting element and having a cam follower engaging the spiral flight, the cam and the cam follower interengaging to reach an end position of the spiral flight preventing further relative angular displacement of the load limiting element beyond a predetermined maximum angular displacement.