Wed 25 Nov 2009
Not many individuals realise that the design of air bags – a soft cushion to land against in a crash – has been in existence for decades. The first patent on an inflatable crash-landing device for aeroplanes was submitted during World War II. During the 1980s, the very first commercial airbags were present in cars.
Right up to today, stats indicate that airbags cut back the chance of death in a straight frontal crash by as much as 30 percent. These days there are also seat mounted and door-mounted side air bags. As amazing as this sounds, some cars go far beyond only having twin airbags, and instead have six to eight airbags.
An airbag’s job is to ease the forward motion of the driver in just a fraction of a second. There are 3 components to an airbag that help accomplish this job:
- The airbag is made of a slim, nylon, which is compressed inside the dashboard or steering wheel and, these days, the door or seat
- The detector is the device that instructs the bag to balloon. Ballooning occurs when there is a smash force equating to driving into a brick wall at 16 to 24 km an hour. A mechanical switch is flicked when there’s a weight shift that cuts off an electrical contact, notifying the detectors that a crash has taken place. The sensors receive data from an accelerometer that’s part of a microchip
- The bag’s expansion system reacts sodium azide with potassium nitrate (KNO3) to make nitrogen gas. Hot eruptions of the nitrogen balloon the airbag
Because of the incredibly fast expansion of an air bag, it’s essential the driver and passenger sit in an upright position giving a safe space between their face and the steering wheel / dashboard – this provides time for the airbag to balloon while they are being forced forwards by the affect of the accident.
