Seat-belt tensioning mechanism - has lock housing containing piston assembly driven by explosive charge which is detonated from remote sensor

摘要

The mechanism is fitted in the extended part of the belt lock and consists of a cylinder (1) in which the piston (2) operates. The end of the piston rod is pivoted to a suitable part of the car body. The piston rod passes an enlarged part (4) of the cylinder. Between the piston face and the enlarged end of the cylinder is an explosive charge (5) with an angled washer underneath. When the charge is detonated from a remote sensor, piston (2) is driven upwards in the cylinder resulting in a relative downwards move of the cylinder itself so that the belt slack is taken up. The canted edge (8) of the washer prevents the piston rod (3) from slipping back after completed travel of the piston.