PRE-RELEASE
Belt tensioners
| Belt tensioners |
The passenger-side seatbelt pretensioner is connected to pins 37 and 36 on the SRS control module. The driver-side seatbelt pretensioner is connected to pins 35 and 34 on the SRS control module, as indicated under SRS control module , Airbag (SRS) LHD and Airbag (SRS) RHD .
The lead carries test and detonation current from the SRS control module to the seat-belt tensioner.
The seat-belt tensioner consists of an explosive charge which is activated by the SRS control module together with the airbags. The seat-belt tensioners may also be activated separately in the event of a rear-end collision or a less severe head-on collision.
When the charge is detonated it generates a gas under high pressure which drives a piston in an aluminium tube. This piston is connected to the seat-belt reel via a steel wire. The distance travelled by the piston is the maximum length of seat belt that can be retracted and depends on the amount of slack in the belt.
The belt is restricted with a force-limiting torsion component in the belt roller. The torsion component and the airbag balance each other. The belt and airbag thus work together to restrain body movement as comfortably as possible.
