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The Active Buckle Lifter by ZF

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More than just convenience: ZF's Active Buckle Lifter isn't new. All the same, hardly anyone has heard of it. One reason could be that this useful safety and convenience feature so far has only been installed in one vehicle model.
Michael Blumenstein, May 22, 2018
Michael Blumenstein the motor vehicle mechanic, vehicle merchant, press spokesperson and editor is on two wheels on the way since then he can run. This article was first published on the company website,
ZF developed the Active Buckle Lifter around six years ago: an in-house project from beginning to end. The forward thinkers based near Lake Constance are drivers of innovation in the automotive industry. Here in Friedrichshafen and elsewhere, they create technical developments and further them to market maturity.

At the moment, the perhaps most well-known ZF product is the 8-speed automatic transmission. It is currently used by several automotive manufacturers who can thus dispense with their own in-house development – with good reason. ZF is also a pioneer in safety and assistance systems – something that many people are not aware of. Only recently ZF introduced a weight-optimized knee airbag that will be used by a European automobile manufacturer in the coming year.

The Active Buckle Lifter whilst extending

Often, it's seemingly little things that increase safety and convenience, such as the Active Buckle Lifter by ZF. An electric motor moves the seat belt buckle up and down vertically. As soon as the car door is opened, the familiar black buckle with the red unlock button rises approximately seven centimeters out of the seat cushion.
The seat belt buckle is now right where the occupant expects it to be. On the one hand, this makes it easy to buckle the belt without straining or breaking fingernails. On the other hand it simplifies securing children's safety seats or booster seats, as it can easily be felt by hand from the outside. Subtle illumination ensures the seat belt buckle is visible even in the dark.
© ZF
ZF's Active Buckle Lifter before installation

The seat belt is tightened

Once the belt tongue is engaged in the seat belt buckle, the system subtly returns to the starting position where it is not in the way. Not, however, without tightening the seat belt first. This is a process every occupant should carry out themselves after fastening their seat belt, but hardly anybody does. In doing so, the seat-belt slack, the space between the seat belt and the body that especially in winter is always a few centimeters deep due to jackets or thick sweaters, is minimized whilst safety is maximized. After all, more freedom of movement in the seat belt also means more "wiggle room" in an accident.
But ZF's Active Buckle Lifter doesn't just take care of buckling up and tightening. Pre-safe systems have made us familiar with windows that close in critical situations or the short jolt to the belt to indicate a potentially threatening situation, as well as the seat belt tightening thanks to active retractors (hidden in the center pillar) when the driver brakes hard.
In situations such as these, the Active Buckle Lifter pulls back by an additional some 40 millimeters, thus intensifying the connection between occupants, seat belt and seat. If, for example, the active retractor and the Active Buckle Lifter work together, forward displacement of the head can be minimized by around 50 percent compared to standard seat belts, according to ZF. This means less strain on the body and, if it comes to the crunch, the airbag will be exactly where it needs to be.

Seat Belts by ZF

ZF produces a variety of seat belt systems that help improve occupant safety.

Stabilizing occupants

The Active Buckle Lifter can also assist during dynamic cornering or in evasive maneuvers. By tightening the seat belt it stabilizes the occupants in their seats – regardless of which seat they are in. The persons' backs are better supported so that they have to put less effort into resisting centrifugal forces. It is even technically possible to already tighten the system before reaching the curve or braking abruptly. By means of analyzing GPS, camera and vehicle data it is possible to calculate whether the stretch of road ahead will require hard braking or steering.
In addition, the seat belt spans the pelvis optimally, which again results in a decreased risk of injury in a crash. Speaking of which: The Active Buckle Lifter loosens after a crash and extends by the previously mentioned length to make unbuckling faster and easier.
Until now the system has been integrated exclusively in the Mercedes-Benz S-Class according to the automotive manufacturer's specifications. And only in the rear. In the front the previously mentioned retractor tightens the seat belts. Mercedes says that the development of Active Buckle Lifters was mainly aimed at Asian markets, where only around 30 percent of the rear passenger compartments of Mercedes-Benz S-Class models are occupied during travel. However, due to the seating capacity, occupants don't always sit exactly in spots that would be ideal from a safety point of view. Here the Active Buckle Lifter also helps by gently guiding people into a better seating position.
© ZF
ZF's Active Buckle Lifter is used in the rear of the Mercedes-Benz S-Class, for example.