ZF Lifetec has engineered the new SPR6.1 seat belt, which will launch in mid-2025, according to a press release. The SPR6.1 improves available options for vehicle safety in the rear seats and goes beyond the existing safety requirements for passengers in the rear, according the release.
Due to a unique mechanical decoupling, the system can better adapt to passengers of different weights in the event of a crash. The feature is said to provide real-life safety and more comfort for rear seat passengers.
“With the SPR6.1, we have developed a solution that significantly increases rear seat safety while improving passenger comfort,” said Harald Lutz, senior vice president Global Engineering at ZF Lifetec. “Our innovations in passive safety technology continue to set standards and help us achieve our goal of Vision Zero - zero road fatalities and serious injuries.”
The SPR6.1 combines the advantages of variable pre-tensioning through the torsion bar with the compactness of pre-tensioning through the spool. In vehicles with autonomous emergency braking, the occupant could move forward due to a pre-braking initiated just before a crash. The sensors of the locking mechanism detect this braking deceleration and mechanically restrain the occupant.
In the event of an accident, the snake pretensioner retractor, which is a plastic driving element, will be pressed into a special gear by a pyrotechnical drive. It ensures a tightening of the seat belt up to the point of mechanical decoupling to avoid excessive force loads.
The mechanical decoupling of the belt also offers greater variability in the use of additional belt pretensioners in the same system. For example, the use of an additional anchor pretensioner could reduce the risk of submarining without increasing the risk of injury to the occupants.
The SPR6.1 offers a wide range of applications and has direct and indirect retraction uses. It is also compatible with a range of sensors that mechanically lock the belt retractor including a standard vehicle-sensitive ball sensor or a premium silent locking side pendulum sensor. At just 8 dB, the SLS is barely audible even in the quietest electric vehicles. The low noise level is a comfort factor, especially in the rear seats, where the belt pretensioner is often at ear level.
