What is a Seat Belt Pretensioner?

By July 31, 2017 Seat Belts No Comments
Seat Belt Pretensioner | MyAirbags

A pretensioner is a device that is connected to the safety belt buckle, safety belt retractor or/and outboard lower safety belt anchor assembly. The pretensioner tightens the seat belt during certain crashes. Pretensioners may deploy with or without airbag deployment. Depending upon the vehicle, pretensioners may activate in certain frontal, side, rear and/or rollover crashes. For some vehicles, pretensioners will deploy if the safety belt is buckled.

Buckle Pretensioner

The buckle pretensioner uses a pyrotechnic gas generator to propel a piston that is attached to the safety belt buckle with a cable. The cable pulls the buckle down toward the seat tightening the belt.

Seat Belt Repair Buckle-Pretensioner Repair

Anchor Pretensioner

The anchor pretensioner uses a pyrotechnic gas generator to propel a piston that is attached to the outboard lower safety belt anchor assembly with a cable. The cable pulls the anchor assembly down toward the floor tightening the belt.

Seat Belt Repair Anchor Pretensioner

Retractor Pretensioner

The retractor pretensioner uses a pyrotechnic device that “backwinds” the retractor spool tightening the belt.

Seat Belt Repair Retractor-Pretensioner Repair

Use the same precautions you would for the other SRS inflatable restraint components. There may be power to activate a pretensioner for a short time after the battery is disconnected or the ignition is turned off.

 

Once an international man of mystery, John has settled down and now spends his time making the world a better place, one car part at a time!