Patent ID: 6367729
Filing Date: 2002-04-09
Classification: B60R

Abstract:
A seat belt retractor in which said seat belt retractor comprises: a spool for winding a webbing; andan emergency locking mechanism including: a ratchet wheel which rotates together with said spool; and a pawl which meshes with said ratchet wheel in response to emergency detection by inertia sensing means, thereby setting said spool into a locked condition via said ratchet wheel, and a torsion bar is disposed between said spool and said ratchet wheel, one end of said torsion bar being coupled to said spool, another end of said torsion bar being coupled to said ratchet wheel, said torsion bar being subjected to twist deformation to absorb an impact when a force in a drawing direction acts on said webbing in an operating condition of said emergency locking mechanism, and characterized in that a coupling portion of said torsion bar with respect to said ratchet wheel is formed into a polygonal shape, a polygonal insertion hole into which said polygonal coupling portion is to be fitted is formed in said ratchet, and a rib-like projection is formed on an inner face of said polygonal insertion hole in an axial direction of said torsion bar, said rib-like projection biasing, when said webbing is drawn, said torsion bar in said insertion hole in a direction along which said torsion bar rotates, to cause respective faces to be in press contact with each other in the direction.