Patent ID: 7374122

Claim:
A seat belt retractor comprising: (a) a spool mounted for rotation for retraction or pay-out of a seat belt webbing depending upon the rotation direction of the spool; (b) a locking ring attached to one end of the spool; means for locking the locking ring against rotation when a crash condition is sensed; and (c) a force limiting means for allowing further pay-out of the seat belt webbing after the locking ring has locked, under the influence of a vehicle occupant's forward momentum, coupled in the force path between the spool and the locking ring, the force limiting means comprising (i) a primary force limiting means; and (ii) a secondary force limiting means comprising an elongate deformable member, arranged such that relative rotation between the spool and the locking ring causes a predetermined length of the deformable member to be pulled out of passageways or holes in the spool and be deformed during a first stage of load limiting, wherein the cross-sectional area of the deformable member is uniform over a major portion of the predetermined length and is reduced over at least one minor portion located a distance from an end of the member in a region of a bent part of the deformable member located in a recess formed between the spool and the locking ring to reduce an initial bending moment of the deformable member when the deformable member is pulled out of the passageways or holes in the spool.