Scott Dorsey wrote:
> In article >, Steve W. > wrote:
>> wrote:
>>> Cars I have driven had explosive pre-tensioners. I learned there was also
>>> mechanical spring pre-tensioners. Which vehicles used these?
>> Usually those are only in the bargain basement vehicles not sold in the US.
>
> The first cars I drove with seatbelts had no mechanism at all, you just
> adjusted the shoulder belt to fit you and it didn't move in or out. People
> hated them.
>
> For many years, seatbelt systems used a ratchet retractor gadget that
> allowed the seatbelts to be pulled out slowly but they would stop if they
> were pulled out too quickly.
>
> I don't know of any mechanical pretensioners, although I would not be
> surprised if they existed in the transition period between retracting belts
> and the modern explosive pretensioner.
> --scott
>

They are more common outside the US. Basically a simple inertial weight
and spring with a pawl that releases and locks the belt, same basic
design as the child seat style belts but self locking if the weights
trigger them.

--
Steve W.