INFLATABLE SAFETY BELTS BRING AIR BAG TECHNOLOGY TO RESTRAINTS

Inflatable safety belts may offer potential to reduce head and neck injuries. The tubular air bag covers virtually the entire area where the shoulder belt makes contact with the torso.

DEARBORN, Mich.,October 13, 2004; Advances in air bag inflation and construction methods have allowed engineers to develop an inflatable bag that can deploy from within a shoulder belt in the event of a crash. This tubular air bag would cover virtually the entire area where the shoulder belts makes contact with the torso.

"While this technology is still under development by Ford and would face extensive crash testing and analysis to fine tune its deployment characteristics, it appears to offer promise along many fronts," says Priya Prasad, Ford Motor Company Technical Fellow in Biomechanics and Occupant Protection, Ford Research Laboratory.

The inflatable safety belt technology is unique in many ways:

The pillow-like cushion across the shoulder and upper chest may be able to limit "whipping" forces on the head, with the potential to reduce head and neck injuries. Inflating the area alongside the torso belt may provide many of the same benefits as pretensioner devices - tightening the belt-to-chest contact before crash forces are transmitted, positioning the person in more favorable relation to other safety devices in the vehicle. The broader contact area of the inflatable safety belt has the potential to spread impact forces across the chest, reducing the chances of injury.

Prasad says new crash testing methods would be required to understand the effectiveness of the inflatable safety belts completely.

"Current test dummies are geared toward impact measurements, and may not be able to provide the detailed chest pressure information needed," Prasad says. "However, initial studies have shown the safety belt air bags have potential to reduce head impact injuries by 50 percent."

Another key consideration in further development of this technology will be garnering public acceptance. Safety research engineers want to make sure the new belts are so comfortable that they don't deter use.

Here's how the inflatable safety belts work:

The belts are deployed through cold-inflation, using compressed air rather than a heat-generating chemical reaction. This guarantees that the surface of the deploying air bags is no more than 18 degrees Fahrenheit (10 degrees Celsius) higher than the ambient air temperature. This would help eliminate the potential for burn injuries. This is especially important because unlike most air bags, these would deploy in contact with the torso. The inflator resides inside the vehicle's B-pillar or at the attachment point of the lap belt buckle. Inflation gases are delivered to the air bag through a tube. The air bag begins at a point just over the shoulder. The undeployed bag is folded and encased in a break-away fabric cover that is slightly wider and thicker than a traditional safety belt. As the air bag inflates to a diameter of about six inches, the covering falls away and the tubular-shaped air bag emerges. Consumer clinics have indicated that customers overwhelmingly preferred the padded feel of a prototype inflatable belt to a conventional shoulder belt.

"These inflatable safety belts could bring many of the advantages of air bags to rear-seat passengers," Prasad says.