GB1374931A - Inertia-locking safety belt retractor - Google Patents

Abstract

1374931 Inertia-locking safety belt retractor R C FISHER 2 March 1973 [3 Nov 1972] 10191/73 Heading A3V An inertia-responsive safety belt retractor comprises a take-up spool 16 for a belt 12 journalled in a frame 46 and having ratchet teeth 111 on its peripheral flanges, a locking pawl 98 mounted on the frame and having locking projections 108, 110 engageable with the ratchet teeth 111, a spherical inertia responsive member 210 on a conical seat adapted on inertial displacement relative to its seat to pivot the pawl 98 into its locking position to prevent belt withdrawal, and further projections 118, 120 on the pawl to balance the latter dynamically against inertia forces in the horizontal "A" plane thereby ensuring that the pawl responds only to displacement of the member 210 and is insensitive to spurious inertia forces. In the embodiment shown the member 210 bears on a tab 112 on the pawl through a plunger 212, but the inertia member may be set higher and bear directly on the pawl. The pawl is additionally statically balanced so as to have a slight counter-clockwise bias against the plunger 212. In the locking position of the pawl, a line through each of its support points on the frame 46 and the corresponding point of contact with the ratchet teeth 111 is tangential to the periphery of the spool. The slope of the conical seat determines the inertia force required to effect locking of the retractor. The following abridgment is included in this series since the Specification was through an error, not allotted to this group. Reference to it will be found in the name index to this volume.