Inflatable seat belts may protect passengers

Friday, August 10, 2012 by: David Gutierrez, staff writer
Tags: inflatable seat belts, autos, passengers

(NaturalNews) Two major auto companies have begun rolling out a new safety feature known as inflatable seat belts to help compensate for the inability to install frontal airbags in the back seat of cars. Already featured in the Ford 2011 Explorer, the seat belts are slated to be included in other Ford models soon, as well as a still-unspecified Mercedes luxury vehicle.

Normal seat belts are designed to stretch forward in the event of a collision in order to not only prevent the passenger from smashing into the interior of the car or other passengers, but also to lessen the force experienced due to slamming against the seat belt instead. Inflatable seat belts operate by a slightly different principle of physics. When a severe frontal collision is detected, inflatable seat belts fill with gas - much like airbags - and expand horizontally, thus spreading the impact out over a larger area of the passenger's chest and thereby decreasing the pressure of the impact and the damage that goes along with it. The inflatable seat belt also helps minimize and control motion of the head and neck.

The seat belt is used, looks and feels just like a normal seat belt. In fact, 90 percent of people surveyed in Ford's research reported that the inflatable belt was either as comfortable or more comfortable than a conventional seat belt. Velcro seams connect many thin layers of fabric that compress the belt down to its normal size; in a collision, the expanding gas causes the Velcro to tear apart. Several seconds after inflating, the seat belt expels the gas through pores in its fabric and deflates to allow the passenger to exit the vehicle.

Unlike airbags, these seat belts do not inflate by means of a rapid, heat-fired chemical reaction. Indeed, such a reaction might cause the seat belt to heat uncomfortably in a collision, even dangerously. Instead, the seat belt inflates by means of cold, compressed gas that flows into it from a cylinder underneath the seat. The cold gas also allows the seat belt to fill more gently and slowly than an airbag, since the belt does not need to expand rapidly enough to fill the space between the passenger and the front of the car.

Innovations in auto safety

Since front seats already come equipped with air bags, the inflatable seat belts will be installed only in rear seats, perhaps along with side air bags and, in Mercedes vehicles, the company's new "active seat-belt buckle."

The active buckle, also slated for inclusion in forthcoming Mercedes luxury cars, is programmed to raise itself up 70 mm (1.2 inches) out of the seat whenever the rear doors are opened. The buckle's insertion slot also lights up. The idea is that this moving, glowing buckle will be easier to find and use, particularly for children or in the dark, and that it will make passengers more likely to use it by drawing attention to itself. The same effect will occur even if the seat belt is already buckled, to make it easier for safety personnel to rescue passengers in case of a crash.

The buckle is also programmed to sink up to four centimeters (1.6 inches) back into the seat after being buckled, to take out slack and customize seat belt tightness to the individual passenger.

Both inflatable seat belts and active seat-belt buckles were tested using virtual human models rather than crash test dummies, which are not designed for the type of innovative safety measures that many auto companies are now experimenting with. Both features were originally showcased in an experimental safety vehicle dubbed ESF2009.

Sources for this article include:

http://news.discovery.com/autos/inflatable-seatbelt-120725.html
http://www.gizmag.com/mercedes-benz-beltbag/23406/
http://www.gizmag.com/ford-inflatable-seatbelt/13286/
http://dsc.discovery.com
http://www.gizmag.com/mercedes-benz-active-seat-belt-buckle/21376/
http://www.gizmag.com