Device for prevention of slap-back lock of inertia reel

Abstract

A conventional webbing-locking inertia reel is modified by integration of a device for the prevention of slap-back lock of the inertia reel upon excessively rapid retraction of the webbing worn by a seat occupant as a safety belt and/or harness. The device also slows the retraction of the webbing enough to prevent a hard collision of the webbing stop at the inertia reel. This is accomplished by interacting the reel shaft with a specially designed damping disk so that both the shaft and the damping disk rotate counter-clockwise when an external force pulls the webbing from its rotatable spool, while simultaneously the shaft also interacts with a conventional housed return spring, causing it to wind and build up a rewinding force, which, when the external force is removed or ceases, causes rotation of the shaft, spool, and damping disk clockwise and rewinds the webbing on the spool. The damping disk is installed in a damper housing section filled with a special high-viscosity synthetic grease so that damping occurs when the damping disk is rotated, due to the shear of the grease that occurs when the two surfaces, that of the damping disk and the housing wall, move relative to each other.