First Commercial Airbag (Nov, 1981)
Mercedes’ steering-wheel air bag
A combination of air bag and seat belt protects the driver who opts for Mercedes’ new safety package. The air bag is the only one offered as a production option by any auto maker.
In an impact of over nine mph, a pendulum sensor on the drive-shaft tunnel detects deceleration. A tiny pellet of solid rocket fuel then detonates; as it burns, it produces nitrogen gas that balloons a neoprene bag from the steering wheel. When the driver hits the bag, it deflates slowly. The driver is also restrained by his seat belt.
Instead of an air bag, an inertial reel belt restrains the front passenger. The same sensor triggers gas from a separate capsule. The gas expands against a piston that forces fluid onto a miniature hydraulic-turbine wheel mounted on the belt reel. This tightens any belt slack in 12 milliseconds. When the ignition is switched on, a dashboard check light glows for a few seconds, indicating that the system is functioning properly. The safety package is available as an option only in Europe on Mercedes S-Class cars. Price: about $620.â€” David Scott