Description And Operation: Description: Notes
Two seat belt tensioners, one on the seat belt anchor (1) and the other in the front and rear seat belt retractors (2) (rear retractors in Europe-Middle East-Africa/EMEA) are deployed by the Occupant Restraint Controller (ORC) in conjunction with the dual front airbags. When the ORC sends the proper electrical signal to the tensioners, the electrical energy generates enough heat to initiate a small pyrotechnic gas generator.
On the retractor tensioner, a gas generator is installed in one end of a steel tube that contains numerous steel balls. As the gas expands, it pushes the steel balls through the tube into a cast metal housing, where a ball guide directs the balls into engagement with the teeth of a sprocket that is geared to one end of the retractor spool. As the balls drive past the sprocket, the sprocket turns and drives the seat belt retractor spool causing the slack to be removed from the front seat belts. The ball trap captures the balls as they leave the sprocket and are expelled from the housing.
On the anchor tensioner, the gas generator is installed in one end of the tubular metal piston housing, which contains a piston secured to one end of a cable. The cable is routed around an integral guide to the buckle anchor, which is secured to the opposite end of the cable. As the gas expands, it pushes the piston and the cable through the tube and pulls the buckle anchor downward, removing the slack from the front seat belt.
The seat belts for both front seats in this vehicle incorporate dual tensioners. One tensioner is integral to the seat belt retractor (2), and one tensioner is integral to the seat belt lower anchor (1). In vehicles manufactured for EMEA markets a single tensioner is also integral to each rear outboard retractor. Each of these tensioner types along with the load limiter are described in further detail elsewhere within this service information.