초록 ▼

A seat belt retractor according to the present invention includes a belt reel rotatably mounted on the side walls of a frame by a reel shaft. The reel is biased in the belt winding direction by a windup spring such as a clock spring or spiral spring having its inner end attached to the reel shaft an

A seat belt retractor according to the present invention includes a belt reel rotatably mounted on the side walls of a frame by a reel shaft. The reel is biased in the belt winding direction by a windup spring such as a clock spring or spiral spring having its inner end attached to the reel shaft and its outer end mounted on a gear which is coupled to the reel by a reduction gear arrangement by which the gear makes less than one revolution during the plurality of revolutions of the reel experienced during belt unwinding from the fully retracted condition to the fully extended condition for buckling about the occupant. The outer end of the winding spring is mounted on the gear at a location furthest away from the inner end of the spring so that during the plurality of belt unwinding revolutions of the inner end of the spring the outer end of the spring chases the inner end of the spring in the direction to relieve the force on the spring and also moves closer to the inner end of the spring so that the torque acting on the reel via the lever arm provided by the gear progressively increases during belt unwinding to lessen the belt winding effort imposed on the belt by the spring.

대표청구항 ▼

A winding spring arrangement for a seat belt retractor having a belt reel rotatably mounted on a housing by a reel shaft for a plurality of revolutions to wind and unwind the belt relative the reel comprising: a sun gear carried by the reel shaft; a ring gear fixedly mounted on the housing and encir

A winding spring arrangement for a seat belt retractor having a belt reel rotatably mounted on a housing by a reel shaft for a plurality of revolutions to wind and unwind the belt relative the reel comprising: a sun gear carried by the reel shaft; a ring gear fixedly mounted on the housing and encircling the sun gear; a planetary gear interposed between and meshing with the sun gear and the ring gear and having a diameter selected relative to the diameters of the sun gear and the ring gear to effect revolution of the planetary gear less than a full revolution during the plurality of revolutions of the sun gear during belt winding and unwinding; and a spirally wound spring having a first end mounted on the reel shaft and a second end mounted on the planetary gear at a point thereon which migrates in the belt unwinding direction of reel rotation from a point thereon diametrically most opposite to the sun gear to a point closest adjacent the sun gear so that the second end of the spring chases the first end of the spring during belt unwinding rotation and also acts through the planetary gear to provide a progressively effective force on the shaft counteracting the torque of the spirally wound spring.