Patent ID: 7410114
Filing Date: 2008-08-12
Classification: B60R

Abstract:
1. A dual-level load limiting seat belt retractor for a vehicle, comprising: a locking base rotatably supported by a frame but locked to said frame in an actual or anticipated crash event; first and second serially arranged torsion bars coaxial with said locking base; a seat belt spool rotationally fixed to an outboard end of said first torsion bar; a bridge bolt rotationally fixed to inboard ends of said first and second torsion bars, and threaded into said locking base; one or more wedges captured in said locking base to block rotation and lateral translation of said bridge bolt with respect to said locking base for establishing a first level of seat belt load limiting due to energy absorption by the first torsion bar; and a switching mechanism selectively activated in said crash event to release said one or more wedges to establish a second level of load limiting due to energy absorption by the second torsion bar.