AIRBAGS(1952)

Hetrick’s invention saves lives in automobile accident

The heating element ignites a chemical explosive. As the explosive burns, it generates a massive amount of harmless gas that floods into a nylon bag packed behind the steering wheel .The gas may be either nitrogen or argon. . Older air bag used sodium azide as their explosive, newer ones use different chemicals. it work by an air bag sensor (Ex: crash sensor) which is responsible for detecting sudden deceleration in a collision. It sends a signal to the airbag computer which uses the vehicle speed, seat belt, yaw and ECU to determine if an airbag should deploy in a crash. The two types of mechanical sensor, the cam type and tube style and ball.

One day in 1952, john W. Hetrick was driving, with his wife and daughter in the front seat, when he had to swerve and brake quickly to avoid the obstacle. Instinctively, he and his wife put their arm out to shield their daughter in case of crash. This inspired him to provide automobile with airbag to protect people during accident. he had been an engineer in the United States, navy during world war II, and he recalled a compressed air torpedo accidently turning itself on, causing its canvas cover to shoot “up into the air, quicker than you could blink an eye”. In 1952 hetrick proposed using compressed air to inflate air bags during car crashes. He received patent for his invention in 1953, but car manufacture in 1950s.

The three main components in airbags are bag itself, a sensor for measuring the severity of the crash, and gas to inflate the bag in a severe. Although air bags have saved thousands of lives, they are not sufficient to prevent death and injury during crashes  

Ford’s president Donald Petersen shows an air bag to U.S. Transportation secretary Elizabeth dole in 1983