Retractor spool

摘要

A seat belt retractor comprising a spool (1) mounted on a spool shaft (10) for rotation in the retractor, a length of seat belt webbing (22) wound on the spool (1) for retraction or pay-out depending on the rotation direction of the spool; means for locking the spool shaft (10) against rotation when a crash condition is sensed; force limiting means for allowing further pay-out of the seat belt webbing after the spool shaft has locked, under the influence of an occupant's forward momentum in the crash condition, wherein the force limiting means comprises an energy absorbing arrangement connecting the spool (1) to the spool shaft, the connection being rigid below a predetermined force, and above the predetermined force there being relative rotation of the spool with respect to the spool shaft to allow pay out of belt webbing, and wherein the energy absorbing arrangement of the force limiting means comprises a slipping clutch (7) connecting the spool (1) to the spool shaft co-axial with the spool (1).