How Seat Belts Use Tiny Explosives To Save Lives During A Collision – SlashGear

The seat belt’s cousin, the air bag (which was unfortunately the subject of a worrying report about potential safety issues for certain vehicles in May 2023), explodes into action in a literal sense. Devastating road accidents can take place in microseconds, so how do you make precautionary measures fast enough to be effective? 

In 1964, engineer Yasuzaburou Kobori devised a sodium azide-burning solution, which was combined with silicon dioxide and potassium nitrate, according to Chemical & Engineering News. The explosive reaction produced enough gas to inflate an airbag in a blink of an eye, or literally quicker. 

Seatbelts, too, need to be able to react at lightning speed in order to save lives, and therefore employ tiny explosives in a similar fashion. With the goal of preventing drivers or passengers from being thrown through the windshield of a vehicle, seat belts are designed to clasp on, thereby limiting or preventing trauma to the body. A pretensioner, through the use of an igniter and electrodes, reacts instantaneously to an accident, as explained by Real Engineering on YouTube. The resulting reaction launches the small “teeth” of the device forward into a pinion, which causes the belt to retract.

The chemical blend used in airbags may have changed since Kobori’s original creation, the precise mechanics of seat belts also may differ from vehicle to vehicle, but these seemingly humdrum vehicle features have some surprisingly intricate technological features beneath the surface. Long may they combust to save lives.