[T2] Seat belt extenders-now inertial dampening + plug for bike helmets!

[david raistrick]

> On 10/28/2016 10:52 PM, Robert Mann wrote:
> A locked belt if firmly fastened prevents the body from gaining much
> momentum before slamming into the rigid limit of the belt.  I was in a
> head-to-tail at c.40 mph in a near-new car with the modern type of
> 'inertial' belt.  My breastbone was severely bruised, costing me plenty
> sleep for 2 – 3 wk.


So truly modern (ie, current) seat belts actually -pull- the seatbelt
back toward the occupant at the time of impact to eliminate the slack
involved in inertial belts.   A variety of mechanisms are used, but
the most common (I believe) is actually just an airbag style explosive
attached under the seat - the explosive fires and pulls a cable which
tensions the belt for a brief moment, enough to arrest (and ideally
prevent) forward momentum.


In a car, particularly with a airbag, you don't want the occupant
moving forward and gently slowing down - there just isn't room or time
for that.    Without an airbag, you have the steering wheel to contend
with - and with airbags, well...you dont want to be moving forward
when that thing hits you. :)


Of course - no one is installing modern retractable seatbelts into a
bus, so.... :)


....david