Seat Belt Systems: Description and Operation

Tear Loop Seat Belt Buckle

Fig. 1:

This unit is designed to control the rate of forward travel of the occupant towards the deployed airbag.

Description
The mechanism within the buckle assembly is designed to release additional webbing when the stitching, which retains the webbing loops, breaks under a predetermined load.

The wires within the buckle (1 Fig. 1) have the following functions:

To protect the stitching from 'normal' loads such as heavy braking or cornering.

To control the rate of deployment.

To support the extended head following deployment.

When the unit has been activated the buckle will extend from the shroud and reveal a warning label (2 Fig. 1). The extent of deployment will depend upon the severity of the load.

WARNING: IF THE LABEL IS VISIBLE AT ALL (3 FIG. 1), THE COMPLETE ASSEMBLY MUST BE RENEWED, AS MUST ANY SEAT BELT WHICH HAS BEEN WORN IN AN ACCIDENT.