Stuttgart. The Beltbag, one of the highlights from the ESF 2009
Experimental Safety Vehicle, is due to go into production in a
luxury-class model from Mercedes-Benz. The inflatable seat-belt strap
is able to reduce the risk of injury to passengers in the rear in a
head-on collision by lessening the strain placed on the ribcage.
Should the crash sensors detect a severe frontal impact, the airbag
control unit will trigger deployment and inflation of the Beltbag. A
gas generator then inflates the multi-layered belt strap with Velcro
seams to nearly three times its normal width. The resulting larger
surface area is able to better distribute the force acting on the seat
occupant, thereby reducing the risk of injury.
The Beltbag can be used in exactly the same way as a conventional seat
belt. The belt strap's design is different from that of the standard
belt though, and received top marks in practical trials for being
extremely comfortable to wear and for its extra-soft belt strap edge.
"Mercedes-Benz is pursuing its safety initiative in the rear of
vehicles with the Beltbag," comments Prof. Dr.-Ing. Rodolfo
Schöneburg, Head of Passive Safety and Vehicle Functions at
Mercedes-Benz Cars. "After all, the excellent standard of safety
offered by Mercedes-Benz doesn't just apply to all model series, but
to all seats, too."
Just like the active seat-belt buckle recently presented by
Mercedes-Benz that is likewise earmarked for inclusion in a luxury
model, the Beltbag was developed with a particular view toward new
markets. There, the occupancy rate in the rear is as much as 30
percent, making it much higher than in Europe. By introducing the
Beltbag, Mercedes-Benz is further expanding the safety system for
passengers in the rear – in contrast to many other manufacturers, seat
belts in the second row of Mercedes-Benz models already come equipped
with belt tensioners and belt force limiters. It is not planned to
introduce the Beltbag for the front occupants, as airbags are already
included in the front on all models as a supplementary restraint
Because dummy measurement technology is not capable of quantifying the
benefits resulting from a wider belt strap, such as the lower force
exerted on occupants, the safety experts at Mercedes have also been
working intensely with virtual human models, as such
computer-generated models make it possible to obtain detailed findings
on the biomechanical strain during a collision.