ZF LIFETEC, a German company that creates technology-driven safety systems for vehicles, has announced the development of a heel air bag. 

The air bag is designed to increase protection against injuries in the front seat while supporting the frontal restraint system, consisting of the seatbelt and front air bag. 

According to a news release, the air bag improves protection by transferring some of the restraint energy into the vehicle via the knees and thighs. It notes that the occupant’s feet are required to be positioned in the footwell during a crash. 

“In the future, when seats can be moved further back and into so-called comfort positions, a suitable contact surface for the feet might be too far away,” the release says. “In the event of an accident, the resulting uncontrolled movement of the legs can increase the risk of injuries to the lower extremities.”

Lower extremities injuries are not typically life-threatening but can cause long-term damage to the musculoskeletal system of the driver and front passenger. 

Conventional seating positions provide sufficient support for the feet of front seat occupants to ensure a stable heel strike point that allows for a controlled knee path, the release says. If equipped with a knee air bag, the knee joint can enter the air bag at the most favorable angle that allows a large portion of the crash energy to be transferred by the femur, the strongest bone in the human body. 

“Crash tests have shown, however, that an additional heel impact point must be created once the occupant pushes his seat back and adopts a more comfortable sitting position, as this increases the distance between the heels and the impact point, meaning that the coupling to the footwell floor is no longer optimal,” the release says. 

If the heel strike point is missing, the knee joints can no longer be supported in the intended position, causing the legs to move uncontrollably, according to Herald Lutz, head of development, in the release. 

An Active Heel Airbag can be activated by a comfort position button or by camera-based interior monitoring on the driver’s side, the release says. 

“The Active Heel Airbag can be integrated directly into the footwell without requiring additional space,” the release says. “In the event of a crash, the air bag inflates under the vehicle’s floor carpet, providing the necessary heel stability. The Active Heel Airbag can be adapted to almost any vehicle model worldwide. The Active Heel Airbag will be available in 2028 for automakers who want to offer their passengers seats with additional comfort positions.”

IMAGE

Photo courtesy of ZF LIFETEC