Patent ID: 6371397
Filing Date: 2002-04-16
Classification: B60R

Abstract:
A seat belt retractor comprising:(a) a winding shaft for winding a seat belt webbing thereon; (b) a motive spring for biasing the winding shaft in a direction for winding the seat belt, the motive spring being located in a rotatable spring casing; (c) a drive unit for the at least partial relaxation of the motive spring when the seat belt is at least partially unwound, the torque of the drive unit can be transmitted to the rotatable spring casing; and (d) a clutch member that produces frictional contact for transmitting torque between the drive unit and the winding shaft such that the winding shaft can be driven directly by the drive unit during a winding process of the seat belt, the clutch member has an annular portion that is connected to the winding shaft and has a greater diameter than the diameter of the winding shaft, the clutch member comprising at least one helical wrap spring that surrounds the winding shaft in an annular manner and has one end that is connected in a non-rotatable manner to the drive unit, the clutch member changes shape elastically under the influence of a torque and comprises at least one damping element, the clutch member is connected in a non-rotatable manner to the spring casing and is brought into rotational engagement with the winding shaft by the helical wrap spring for transmitting torque from the drive unit.