Rear Seatbelt Tensioners

Rear Seatbelt (End Fitting) Tensioner

If the rear airbag package is ordered, end fitting tensioners are fitted for the outer rear seats. In the middle, a three-point automatic belt is fitted. (The basic version has 3 three-point automatic belts.)

The rear seatbelt consists of the following components:




The rear end fitting tensioners have the same task as the seatbelt tensioners at the front, that is removing the slack in the belt during the crash as well as early binding of the occupant to the vehicle deceleration (called riding out the crash).

Since the space available beneath the rear seat is limited, it meant that a component similar to the front seatbelt tensioner could not be used, a new solution had to be found.

The belt slack is removed by drawing in the seatbelt strap at the end fitting point. The inertia reel seatbelt forms the upper attachment point, the end fitting tensioner is the lower attachment point.

The end fitting tensioner consists of the following components:




Operation

The rear seat satellite (SSH) ignites the ignition stage in the event of a crash if the seat has been detected as occupied.

When the gas generator ignites, the rise in pressure shifts a plunger in the pipe. The cable end is drawn in the pipe in a linear direction by the plunger. The other cable end is wound by a pulley and turns the belt winding shaft.

A roller coupling blocks the belt winding shaft so that when force is applied into the belt system after the tensioning process this can no longer be turned back. The end fitting tensioners tighten the belt slack at the pelvic area first and then the chest area belt slack.

The tensioning path is determined by the cable pulley diameter and the usable plunger travel. The maximum tensioning length is approx.150 mm.