Seat Belt Systems: Description and Operation

Front Seat Belts:

Each front seat belt is in color-keyed webbing with plastic moulding on the running loop and tongue and has three anchorage points. The front seat belts are common to both coupe and convertible models. Differing top fittings are selected and fitted as appropriate on installation. The coupe also has a manual, four position, belt shoulder height adjuster installed in each 'B' post. On each model, the front belts are also left- and right-handed.

Rear passenger entry and exit is aided by slider bar outboard lower mountings and each belt buckle is secured to a moving inboard seat rail by a strap that enables the seat to be moved without adjustment or removal of the belt. Visual and audible warnings operate if the driver's seat belt is not worn when the driving seat is occupied and the ignition is switched to position I or II.

Rear Seat Belts:

Two rear seat belts are dedicated to installation in the coupe or convertible, each has three anchorage points with emergency, and where applicable, automatic locking retractors. The belt buckles, common to both models, are each mounted on twin cables and share a single central floor anchorage. The buckle cables exit the rear seat cushion via a tailored penetration concealed by a matching gaiter.

Coupe belt retractors are mounted on the outboard sides of the parcel shelf, with belt webbing exiting via color keyed escutcheons in the quarter casings. Convertible belt retractors are mounted on rear seat pan behind the seat squab. Belt webbing is routed upwards inside the seat belt tower and exits via color keyed escutcheons surmounting the rear seat squab. The lower anchorage points, located on outboard sides of the seat pan, are common to both models. All seat belt retractors incorporate emergency locking (ELR), which locks the retractor unit under rapid deceleration of the vehicle. At all other times the wearer is free to move the upper torso.

Automatic locking retractor (ALR) fitted for certain markets, enables a child seat to be secured by any passenger seat belt. When adjusted with all slack removed, the ALR locks, preventing further belt extraction. Unclipping of the buckle allows the belt to return to the normal stowed position and revert to ELR operation. For some markets, child seat anchorage points are located on the body.

NOTE: Only complete seat belt assemblies are available as serviceable items.

Pyrotechnic Seat Belt Pre-tensioners:

Each front seat belt has a pyrotechnic device with independent mechanical sensing and pre-tensioning retractor unit, installed at the base of the 'B' post. In the event of severe frontal impact, this provides additional occupant protection by removing any excess slack from the seat belt. Seat belt pre-tensioning activates when a frontal impact of sufficient force occurs within 30 degrees of vehicle center line. Under such an impact, mechanical sensors in the retractor unit fire, igniting the pre-tensioner gas generator. The gas generator initiates a chemical reaction, producing gases under pressure. Gas pressure drives the piston/cable up a tube, rotating the retractor spindle and removing excess slack from the seat belt. The mechanical sensor is made live by screwing the arming pin in to fully depress the red arming button.

The pre-tensioning system can only be activated if a safety lever is re-set by fitting the associated belt to an occupant or child seat. When the pre-tensioner unit has been activated, the seat belt will lock and cannot be retracted or pulled from the reel.

No attempt must be made to dismantle a retractor unit as unactivated pre-tensioning components contain a solid, flammable material. There are no serviceable parts. If a pre-tensioning unit is inadvertently ruptured and ingestion or inhalation of the propellant occurs, first aid must be applied and medical advice sought.

When handling the piston housing, the piston must be pointed downwards and away from one's self and other personnel. Fingers must be kept away from the take-up spool mechanism.

Any unit dropped from a height greater than 0.3 m (12 inches) must not be fitted to a vehicle.

If a seat belt pre-tensioner activates, a small quantity (less than 1 liter) of gas is produced containing nitrogen, oxygen and water vapor.