Abstract: A safety belt retractor including a spring driven belt storage shaft which is locked by either an inertia sensitive, or belt withdrawal sensitive mechanism, or both working together. The width of the retractor is reduced by using a plate-like mass or disc as an inertia sensing mass. The disc is supported, on edge, in a well of a carrier. The carrier can be located in different rotary positions, to adjust the rest position of the mass, by means of meshing gear wheels, one arrangement providing a vernier adjustment. Movement of the mass is sensed by a lever arrangement including a light strip mounted to pivot on, or to rotate with a locking pawl.

Abstract: Safety belt retractors are disclosed in the form of spring driven belt rewinding mechanisms. In some arrangements, a pair of spiral springs act in series or in parallel, one spring applying a constant rewinding torque to a belt storage shaft, the other storing energy when the belt is withdrawn. A ratchet maintains the stored energy and is disengaged by a screw threaded actuator, which moves coaxially to the storage shaft, when the shaft rotates through a number of revolutions. The stored energy is released to supplement the rewinding torque of the first spring. In another arrangement, the ratchet is replaced by an over center spring assembly. An epicyclic gear box drives a coil spring anchorage through a given arc to give an over center action.