http://www.hotwired.com/Coin/Spnsrs/Volvo/Safety/belts.html (The Risc Disc Volume 2, 10/1995)
A Volvo Patent
Eventually, the rest of the world's car maker adopted the three-point
seat has saved millions of lives. Volvo still holds a patent on the
slip-joint anchor that distributes momentum force evenly across the
body and pelvic area. And in 1985, our innovator Nils Bohlin was
chosen by the Patents Bureau of the Federal Republic of Germany join
the honor roll of inventors whose contributions to life in our time
have been of lasting importance-alongside Rudolf Diesel, Carl
Benz, and other legendary names.
Inertia Reel
Volvo three-point seat belts are self-adjusting, designed to fit securely across the shoulder and around the waist yet still provide freedom of movement. A simple mechanism called the inertia reel permits the belt to be drawn in and out slowly, but locks the belt instantly in response to rapid movement. At hard braking, a pendulum device inside the inertia reel will sense sudden vehicle deceleration and automatically lock the belt tight. The inertia reel also rolls up the seat belt slack so the belt is stored conveniently when not in use.
Polyester Belt
The material used in Volvo's three-point seat belts is very strong: a
specially designed polyester tested to withstand loads up to 7,900 pounds. By comparison, that's more than twice the weight of the car itself.
Pre-Tensioner
Another safety system makes Volvo's three-point seat belt design function even more efficiently in a collision: a pyrotechnic pre-tensioner that automatically takes up any slack in the belts at the moment of impact. It works in a split-second, before the weight of a body can fall forward against a loose belt. The pre-tensioner operates by receiving a signal from the sensor unit under the driver's seat (the same sensor that activates the air bag supplemental restraint system), which triggers a small explosive charge that activates a piston to pull a cable and remove any slack in the belt due to heavy outer clothing, reel slackness, twists, or other causes. Pre-tensioners are connected to the front seat belts of Volvo 900-series and 850 models.
Rear Seat Belts
For years, riders in the rear seat of a car were a forgotten element in the passenger restraint safety equation. Volvo has helped to change that, by installing three-point seat belts in all three rear seating positions.
Problems, Questions or Comments, contact: www@organic.com
