Why do seatbelts stop when you pull them hard?


EDIT: I understand that it’s supposed to be for safety. I’m asking because I’ve only experienced the stopping mechanism when I pull. I’ve hit the brakes very abruptly before but nothing. Should I get it looked at?

In: 2

Because that is literally their function – to stop you from suddenly lurching forward and pulverizing your skull against the windshield.

Imagine you get into a car crash. Your car stops where it is, but your body keeps moving until it hits something.

If you weren’t wearing your seatbelt, or its retention mechanism failed, then you’d fly forward and crush yourself against your steering wheel or the passenger dashboard or against the back of the seat in front of you.

Instead, the seatbelt is designed so that if it experiences such a rapid motion, it locks itself so that you *don’t* fly forward.

Because if they didn’t they wouldn’t be very useful restraining people in a crash.

If you mean to ask how they do it, there is a mechanism that spins as the belt extends, flinging out an arm that catches on a toothed housing. This locks it in place as long as tension is applied.

Such a mechanism allows you to pull the belt out to put it on, but also stops you from going through the windshield in a collision.

Safety? Did you think it was a fashion statement?

Try that again (carefully) while you are already leaning forward a bit. Braking abruptly may not be enough to do the trick if you’re leaning back – there may not be enough momentum left to trigger the seatbelts if your torso coming out of your seat absorbs most of it.