| 摘要 |
<p>A retractor for a vehicle safety restraint which comprises web locking wedges (49a, 49b) which grip the seat belt webbing (19), under certain predetermined load conditions, so as to more securely restrain the vehicle occupant at the beginning of a crash pulse and which includes a load limiting arrangement so as to allow a limited and controlled pay out of webbing at the beginning of the crash pulse. The web locking retractor thus comprises a wedge (49a, 49b) which has an inner gripping surface with a predetermined coefficient of friction relative to the seat belt webbing so that, at a predetermined loading, the webbing slips past the friction surface of the wedge. This may be achieved by using double thickness webbing along a predetermined portion of the seat belt, for example two layers of webbing, or coating the wedge or a part of the webbing with a material (322) which is erodible or deformable and which may be cut into or eroded by the friction surface of the wedge, or by teeth (320) on that surface. Alternatively or in addition, the wedge comprises a cylindrical drum shaped member of which the outer curved surface is the gripping surface, the drum having a torsion bar arranged along its axis fixed against rotation at one end to the wedge housing and fixed to the cylindrical wedge at a point spaced from the end.</p> |
