Note the comments re rotational injuries in the following:
Building a better motorcycle crash helmet
THE enemy of the best is the good enough. That is the lesson which
Kenneth Phillips, a British inventor, is learning the hard way. Dr
Phillips has designed a motorcycle crash helmet that mimics the
protective properties of the human head. Tests suggest that it
provides 60% more protection than conventional crash helmets. If used
widely, it could save many thousands of lives. So far, though, not a
single company has shown an interest in developing it as a product.
When a head hits the ground during a crash, it is subjected to two
kinds of acceleration: linear and rotational. Traditional helmets are
good at protecting against linear acceleration, but offer limited
protection against rotational forces. Rotation, however, can be
particularly damaging. When the brain rotates inside the skull, blood
vessels and delicate membranes get torn.
Dr Phillips, who trained as a physician and saw at first hand the
damage that motorcycle accidents can cause to the head, turned to the
head itself for inspiration for an improved helmet. The scalp, he
observed, provides the brain with protection against rotational
forces because it is elastic, compressible and moves around the skull
without friction. So when a head hits a surface, the scalp absorbs
some of the rotational part of the impact by moving across the skull.
As a result, less energy is transferred to the delicate tissues of
the brain.
To mimic this process, the Phillips helmet has an outer shell of
polyethylene that moves independently of the inner cushion. It really
is that simple. The resulting helmet looks and feels pretty much like
a normal crash helmet. But slow-motion video footage taken during
crash tests at Britain's Transport Research Laboratory, in Berkshire,
shows that the outer shell does indeed move freely around the inner
one, and the head is kept steady.
Dr Phillips claims that his helmet should not be much more expensive
to produce than a traditional motorcycle helmet?and it would
certainly be more cost-effective. He has not, however, been able to
interest any existing crash-helmet manufacturers in making it.
Instead, he has started his own company, Phillips Helmets
(www.phillipshelmets.co.uk), with a view to manufacturing the new
helmets himself.
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk
88% of helmet statistics are made up, 65% of them at Washington University