Belt force limiting device in a seatbelt retractor

The device for limiting the force exerted by a car seat belt comprises a rotating spindle (1), on which the belt is wound, and a torsion bar connected to the spindle which is fitted with a lock which prevents it rotating. A shearable pin (6) is mounted on the spindle which can prevent it rotating but fractures when the force on the spindle is greater than 6672 N. An Independent claim is included for a method for limiting the force exerted by a car seat belt.