US 5,174,521 A · Preloader

Abstract

A preloader for use in a webbing retractor for retracting an occupant-restraining webbing onto a takeup shaft so as to allow the webbing to be applied to the occupant with appropriate tightness. A rotating drum disposed coaxially with the takeup shaft has an annular groove. A wedge member is held around the rotating drum at a certain distance from the rotating drum by a shear pin. A wire is wound in advance around the outer periphery of the wedge member. At the time of a sudden deceleration of a vehicle a driving force is applied to the wire, and the wire in turn tightens the wedge member by being more tightly wound therearound. The shear pin is broken by the tight winding by the wire, and the wedge member is wedge-fitted to the rotating drum, so that the wedge member and the rotating drum rotate integrally and cause the takeup shaft to rotate.

Claims30

Dependent claims

A preloader for use in a webbing retractor for retracting an occupant-restraining webbing onto a webbing takeup shaft so as to allow the webbing to be applied to the occupant with appropriate tightness, comprising:

a frame for rotatably supporting said webbing retractor;
a rotating drum having an annular groove provided on a periphery thereof and connected to said webbing takeup shaft;
wedge means having surfaces capable of being frictionally wedge-fitted to said annular groove of said rotating drum disposed in spaced-apart relation with said rotating drum;
holding means supported on said frame and adapted to retain said wedge means in spaced-apart relation with said rotating drum and to hold said wedge means until a predetermined load is applied thereof;
and
a flexible elongated member wound around said wedge means and adapted to, at the time of sudden deceleration of the vehicle, cancel the holding by said holding means by applying a predetermined load to said holding means and to thereby cause said wedge means to be wedge-fitted to said rotating drum,
whereby said wedge means is wedge-fitted to said rotating drum and rotates integrally therewith so as to forcibly rotate said webbing takeup shaft supported on said frame in a webbing taking-up direction.

4 more elements

a frame for rotatably supporting said webbing retractor;
a rotating drum connected to said webbing takeup shaft coaxially therewith and having an annular groove provided on a periphery thereof;
wedge means having surfaces capable of being frictionally wedge-fitted to said annular groove of said rotating drum, and disposed in spaced-apart relation with said rotating drum;
holding means supported on said frame and adapted to retain said wedge means in spaced apart relation with said rotating drum and to hold said wedge means until a predetermined load is applied thereto;
and
a wire wound around said wedge means and adapted to, at the time of sudden deceleration of the vehicle, apply the load in the direction of a center of said rotating drum by being tightened around said wedge means and to cancel the holding by said holding means by causing said holding means to break, so as to cause said wedge means to be wedge-fitted to said rotating drum and rotate said wedge means and said rotating drum integrally in a webbing taking-up direction;
and
driving means for imparting a tensile force to said wire at the time of the sudden deceleration of the vehicle.

5 more elements

Dependencies are inferred from the claim text.

Preloader

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Preloader

Life of this patent

Abstract

Claims30