Isaac Head and Neck Restraint System


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How Isaac® Works

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Isaac® absorbes the shock of the head moving forward during a crash. Without it, this shock is absorbed by the upper neck and the base of the skull. It works by generating a force which is opposite the crash force. It's not exactly "an equal and opposite reaction," but pretty close.

Half the racing deaths in North America are caused by head and neck injuries, which happen when the body stops but the head keeps moving. Basilar skull fracture occurs at a load of 900 pounds (4.0kN) and happens very fast: in about 30ms, or 3/100ths of a second. This is the same injury caused by a hangman's noose.

In a severe racing crash that generates a 45G impact, the load on the head is approximately 1,800 pounds (8.0kN), about twice the fatal limit. In crash tests Isaac® reduced these loads nearly 90%, to 200 pounds (900N).

The secret to Isaac® is the shock absorber, sometimes called a damper or dashpot. Shocks are easy to move if you move them slowly, but become almost rigid at high velocities. This means that a driver using Isaac® can move their head with little resistance, but in a high G crash the shocks become very stiff, slowing the head velocity and reducing the force on the head.

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U.S. Patent #7,155,747
other domestic and foreign patents pending
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