LOAD LIMITING SEAT BELT RETRACTOR

摘要

An energy absorbing seat belt retractor (20) has a frame (22) and locking mechanisms (60, 60a, 56, 66, 66a) to initially stop a spool (30) from rotating in a belt protraction direction. The spool is biased to retract the seat belt. A two-sided torsion bar (200) generates at least a first level of reaction torque on the spool permitting the spool to rotate in a controlled manner in a belt protracting direction. The torsion bar has a middle portion (202) fixedly coupled to the spool to prevent relative rotation therebetween. A first torsion rod (206) has a first end coupled to a first locking mechanism whereby upon locking of the first end, the first torsion rod is twisted to generate a first level of control force. A second torsion rod (206a) has a second end coupled to a second locking mechanism to generate a second level of control force.