VEHICULAR SAFETY DEVICES

seat belts, harnesses, inflatable cushions, and other devices designed to protect occupants of vehicles from injury in case of accident. A seat belt is a strap that fastens a rider to a moving vehicle and prevents him from being thrown out or against the interior of the vehicle during sudden stops. The first patent for a restraining belt designed to protect passengers in road vehicles was granted to E.J. Claghorn in 1885. The first lap-type belt resembling the modern seat belt was a leather strap used on a United States Army airplane in 1910, and for the next 25 years seat belts were used primarily on aircraft. In the 1940s tests demonstrated that the severity of head injuries could be substantially reduced by holding the body in place with a seat belt, and some seat belts for automobiles were manufactured in the early 1950s. Common automobile restraint systems developed by the early 1970s were lap belts, anchored to the car underbody, to keep the rider from sliding forward; and shoulder harnesses, anchored to the car underbody and the roof rail, to keep the rider from jackknifing into the instrument panel. These fabric belts were provided with quick attach-and-release buckles and were able to withstand loads of 6,000 pounds (2,700 kilograms). Despite convincing evidence of the value of seat belts, however, motorists in all countries were apathetic, and only the passage of legislation caused seat belts to appear universally in automobiles. Even then, widespread failure by drivers and passengers to make use of the belts led to developmental work on passive-restraint systems. Passive-restraint devices protect drivers and passengers without any action on their part. Among those tested was the air bag, an inflatable pillow-like cushion stored in the instrument panel and triggered to inflate in a fraction of a second by the force of impact, cushioning and absorbing the energy of the rider and then deflating. Other important safety devices used on automobiles and other vehicles include safety glass, the newer types of which deflect without breaking under severe stress; improved door locks that keep doors closed under severe conditions; and collapsible steering columns that telescope under impact, absorbing energy.