HORK Enterprises
3221 Quick Road
Holly, MI 48442, USA
 +1 (248) 328-0231
 consult@hork.com

Lower Extremity Protection

Although lower extremity injuries are not life threatening, they are often very debilitating and require long periods of rehabilitation. In case of a post-crash fire or the car sinking into water, such injuries can in fact become fatal. It is believed that bracing the legs against the toeboard, during a frontal impact crash, is a major contributor to the injury mechanisms. This belief appears to be supported by a study of 1990-1994 frontal impact accident data, showing that restrained, intoxicated drivers suffered relatively fewer foot and ankle injuries, than the overall, restrained population. Another contributor to the lower extremity injuries is leg interaction with the instrument panel, resulting from the inevitable forward motion under the inertial forces of the crash. With vital body parts, such as head, neck, and chest protected by seat belts and airbags, the incidence of major traumatic injuries has been reduced. However, non-life-threatening injuries remain a major cause of morbidity. Around two million nonfatal disabling injuries occur annually in the United States alone.

The Seat Cushion Restraint System (SCRS) comprises an activated seat design that acts to eliminate the interaction between the lower extremities and the vehicle interior. It also reduces the interaction between the legs and the instrument panel by limiting the forward travel of the lower torso. It achieves this by inflating an airbag device in the front part of the seat cushion, during the early stages of a vehicle crash. This lifts the legs off the toe board, effectively eliminating the bracing force. It further restrains the lower torso as effective as a lap belt and thereby reduces the interaction of the knees with the lower fascia.

Computer simulation analysis is often the only cost effective way to investigate new ideas and concepts. In 1995 a study was conducted to investigate a device that could mitigate lower extremity injuries.

The Computer simulations helped to determine design parameters such as timing, raise height and loads. During the analysis phase the initial design concept underwent several changes that were vital to it working the way that was intended. The occupant simulation analysis showed a potential reduction of the lower extremity injury measures by as much as 80% for unbelted occupants. The work is fully described in A world-wide patent application for the device was filed in 1995 and a US patent was issued in 1997 under number

This image shows a comparison of a conventional restraint system (left) with the the SCRS (right).

The SCRS effectively lifts the feet off the toeboard and limits the forward travel of the lower torso, with or without a lapbelt, thereby reducing the interaction of the knees with the instrument panel.

The demise of Breed Technologies in 1998 prevented the SCRS concept to be developed into a product. However, similar products have been developed and have been put into production.
In 2006 Autoliv published their Seat Cushion Airbag for the Lexus LS460.
In 2008, we read about the Active Seat Pan airbag of TRW-Delphimetal
A third manufacturer of Seat Cushion airbags, that we know of, is Toyoda Gosei

Seat Cushion airbag installed in the Toyota Yaris.
Courtesy Toyota Press site.

Tracy Law Firm lawyer Todd Tracy advocating for Seat Cushion Airbags.