thomasmnile wrote:
mich800 wrote:
They operate like airbags. They fire a charge when a g force threshold is exceeded to lock the seatbelt.
This is a different mechanism than when you jerk on the shoulder belt and it locks.
When first introduced in the 70's wasn't the pre-collision belt tensioning mechanism purely mechanical, no pyro device? Pendulum device in the retractor or something like that?
Yes and that is still the case. Think of pretentioners as a safety device that activates in a more serious collision. I.E. if the airbags deployed so did the pretensioners most likely.
