Operation

This device consists of a reel with a pyrotechnic triggered mechanism. It is triggered by a percussor the instant in which the mechanical deceleration sensor detects a sufficiently severe frontal impact. The pyrotechnic triggering system and the mechanical sensor are integrated in the reel thus creating a single unit secured to the vehicle riser.

Operation

The device operation is based on inertia caused by vehicle deceleration in the event of an impact. This triggers the pyrotechnic charge which burns producing gas.

The pressure of the gas acts on a piston which is pushed upwards in a cylinder.

The cylinder movement drags a steel wire attached to the seat belt reel. It instantly winds the reel back a few centimetres for several seconds.

Once triggered the seat belt is locked. After the pretensioner has been triggered, the seat belt cannot be used and MUST be replaced.

Safety devices

The pretensioner presents two devices to ensure safety during handling.

SAFETY DURING TRANSPORTATION
The transportation safety device allows to transport the pretensioner without the risk of it being triggered (Unarmed device). It consists of a spring fastened to the reel rod.

When the pretensioner is not installed in a vehicle, the spring holds a tooth on the second safety device. This prevents the deceleration sensor from triggering the device.