Power Electronics

Grammer improves electronic head restraints

In the second generation of its electronically activated head restraints, Grammer AG–Automotive has replaced the gas generator cartridge previously used as a deployment device with an electromagnetic actuator, which releases pre-stressed springs that simultaneously pivot the headrest while moving it forward. The firm says the forward movement should reduce the impact of whiplash injuries in rear-end collisions.

According to the Insurance Institute for Highway Safety (IIHS), few head restraints are designed to align the head with the cervical spine sufficiently to prevent serious injury. Auto-related neck injuries in the United States result in $7 billion annually in insurance claims. Of 73 seat/head restraints dynamically tested by the IIHS, eight were rated "good" overall, 16 "acceptable," and 19 "marginal."

Juergen Huertgen, Grammer’s vice president of sales and marketing for the Americas, says his firm’s second-generation active head restraint system addresses the issues identified by the IIHS. "Unlike the earlier pyrotechnic system used exclusively in the BMW 5 and 7 Series vehicles, the unit is completely contained within the headrest and is independent of the seatback frame," he explains.

The headrest houses two coil springs, a plastic headrest housing, an electromagnetically activated plate and wiring. The two coil springs push the headrest forward after receiving a signal from the vehicle's crash sensor. The electromechanical system weighs 350 grams (12.3 ounces), or about half as much as the earlier system.

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