Crazy how much thought and engineering goes into aparently simple things

Hats off to this girl, she risked her life multiple times just to show us how seatbelts work.

There is a small mistake in this video: The seat belt pretensioner usually doesn't react to brake pedal movement, but rather to the airbag sensors. This means it only triggers when the g-sensors in the front of the car detect a collision, not before that. The advantage of this is that it doesn't go off in a situation where you brake strongly but don't have an accident, for example when you manage to prevent an accident. Since the pretensioner is a single-use device, such a maneuver (even in a voluntary driving safety training, rather than an actually dangerous situation) would make it impossible to use the pretensioner in an actual accident.

Is no one gonna talk about how much accidents she went in for us

The three point seatbelt was invented or designed by volvo and they left it patent free so that every vehicle manufacturers can use it

she really didn't see that boulder in the road tho?

Hey man, 7 years ago I was really wondering how this works. I couldn’t find anything on the internet that was accessible to me and even my physics teacher didn’t know. But I’m very proud to say that my 14 year old self figured out the part with the steel ball. Thank you for your animation, this was really interesting!!!

Very well explained. Nice job!

Don't you hate it when there's a massive boulder in the middle of the road

I see forms of this question coming out multiple times in the comments: "Will the seat belt pretensioners fire in a sudden braking event?" Short Answer: No. Long answer: The video is mistaken, the pretensioners do not fire before an impact, the airbags and pretensioners fire when (depending on the system) the vehicle's impact sensors are triggered and/or an accelerometer in the SRS module detects an impact. When the vehicle hits something, there is time between the initial impact and the vehicle coming to a complete stop. This time is the time in which the occupants of the vehicle must be safely decelerated from the vehicle's pre-collision speed to a stop. The most serious accident is when a vehicle hits a stationary 'non deformable' object (such as the rock in the video). If the vehicle had a 'rigid body' chassis (term used in theoretical physics to mean undeformable) then the vehicle and occupants would have to decelerate to zero instantaneously, resulting in massive injury or death to the occupants. Obviously this is theoretical, and the chassis of the vehicle bends and deforms, all the while decelerating the passenger compartment and therefore the occupants (this is the reason for crumple zones, they are sacrificial components of the vehicle intended to absorb the energy of the vehicle and decelerate it at a rate that is more safe for the occupants. This increases the time from which the initial impact occurs to when the vehicle & occupants come to a stop. During this time after the initial impact, the SRS (Airbag) module uses accelerometers, in many cases additional 'impact ' sensors, and occupant weight sensors (specific layouts vary from manufacturer to manufacturer and model to model) to compute the severity of the accident, determine which aribags/pretensioners to deploy and in some cases how quickly to deploy them (some aribags have multiple stage deployments) , all in fractions of a second (down to as little as 10ms in some cases) and before the force of the impact reaches the passenger compartment. Edit: Note some vehicles do not use 'pyrotechnic' pretensioners (pretensioners that use an explosive charge like the pretensioners described in this video). These Vehicles have different controls, and I am not familiar with these systems.

Never in my lifetime would I figure out how to design something as simple as this

Lost my father to him not wearing his seatbelt, my life would have been much different if he would still be here. I don't know why anyone wouldn't wear a seatbelt your chances of surviving are so much greater.

She's braking with her left foot...

Finally we got a new girl to drive your cars.

The ball bearing is absolutely ingenious! Simplicity at its finest.

it is hands down the best channel on KZfaq! Every video I watch makes me feel 10 times smarter

This high quality video is the kind of content, which is needed on KZfaq. Not those reaction vids, let's plays or beauty blogs. Good job!

Really loved that illustration. Thanks to make easy understanding, how seatbelt is most important.

Incredible engineering design, the developer were appreciated.

This is one of the best channels on KZfaq! Congrats from Brasil!

Several hours ago I in my car wondered how does a seatbelt work. Now I opened KZfaq and the first thing I saw in my subscriptions is this video!

Anyone else’s seatbelt lock up sometimes when your not doing anything

A recent car accident in Gujarat state of India when a famous industrialist was killed and the reason was the non-fastening of the seatbelts by rear passengers. With this background, people are getting paranoid about the working of seatbelts! There is a doubt if the seatbelt shall operate or not in case of crashing of the vehicle! Whenever one sits in a unknown car one should apply a quick tug and the locking mechanism will lock the belt. Seatbelt is a simple mechanical device based on centrifugal force- no sensor, no electronic signal etc etc.A quick tug and the locking mechanism will tell you that it is working as required. Knowing fully well about functioning of Seat Belt one should never forget to put on the seat belt before starting the vehicle. Your video has explained it in all respects ! Thanks 🙏

"what you see in this accident, looks really painful in slowmotion." me: na dude u dead.

6:25 Looking at the massive wobble movement of the front wheel, I am sure even if she didn't crash into the boulder, this imbalance means that her lug nuts are so loose that the front wheel will fall off in less than a mile of normal driving anyways. ^^ No just a joke, love your great animations and couldn't do it better, thats just one thing that fell into my eyesight.

Who tf invented that orange mechanism! That some genius right there I always wanted to know how that works

Fun fact: Volvo have electric pretensioners on newer cars. So the car can actually pretension the belt BEFORE an accident has happened. They also have, since long back, TWO explosive devices - one at the top mount (as shown here in the video, where the roll is) and one at the bottom mount (where it is fastened between the door and the seat). This is because this saves lives since it tension the belt in a better way.

so much thought into something as "simple" as a seat belt...awesome vid

Very interesting, hope to see more of this type of videos.

🤔 BMW refuses to use a driver door, but made a genius technology to safe the computer girl

I love these kind of videos, they are interesting, visual and keep up your attention. This is how teaching should be in schools instead of just reading and memorizing and just copy paste it onto a test paper from memory, then forget about it as soon as you passed your test.

Been driving a 1967 GTO for so long i had no idea this stuff was even on the newish Jeep. Thanks for the great explanation

3:10 We can also test this mechanism works in your car by parking at very steep downhill. and try to pull the seat belt slowly... It just happend to me by chance and came to know about it...

This is amazing. I was surprised that a lot of mechanisms (more than I thought) are used in seat belt. Thank you a lot!!!

Very helpful information.By chance I met this channel today and watch two videos so far. It gave me more details. Definitely will be watching all videos. Keep it up

kudos to this team.......that was an awesome explanation with nice CG,showing all version of seat belt mechanism...

Hey, thanks for your informative illustration on a seat belt working. This uses the fundamental design of mechanical engineering. I studied gear and belt movements but your video shows its real-life application. Once again thanks for sharing knowledge in an animated way.

Simple yet intelligently put together for anyone to understand with amazingly simple visuals so we can follow along. Bravo

wow this is the best explanation you can get. Thanks!

This is the best explanation I found on the internet!

Please make a video on "How *Hill climb assist* works in car?" Or "How *cruise control feature* works in the car?"

My dad always told me that our 2008 Laguna III have an emergency pistons in the seatbelt. Now I just seen how it works. So smart mechanism!

Every part of a car's mechanism is so beautiful

Never thought that, so much engineering is behind the car seat belts. Thank you for the detailed video.

1:36 “Wont Cause Passenger Discomfort” Me: You know what will? THE FACT THE CAR HAS NO DOOR

This lady doesn’t seem like a very good driver, she crashes into a large rock in the road many times. She also doesn’t put a foot on the dead pedal.

Thanks for the eye-opening display !

So beautiful learning video. Thank you very much for sharing.

not gunna lie tho that animation girl is kinda cute

Who are these two that disliked this video? they probably have one of their loved one who did not use it? I dont understand how anyone would dislike this video! damn!

About the second mechanism - its not added just for "testing", and its not added just because if the first mechanism with the ball fails. The second mechanism exist in case the first mechanism doesn't trigger. The first mechanism might fail to trigger (a so called false-negative) without the mechanism failing itself, for example, if the crash/accident come in a slight angle, causing the ball to not correctly catch the lever. In some cases, the centrifugal locking mechanism and the deceleration detection might even be the same mechanism. The ball mechanism is required because if the passenger is wearing loose/fluffy clothes (like a thick winter jacket), it might not accelerate the belt enough fast to trigger the centrifugal mechanism in time. One very common accident that the ball mechanism may fail to detect, is the "left broken light accident during night", which is a common accident during nighttime. When a car's left light is broken (from the point of view of the driver of that car), the car might during the night look like a MC. A second car might then try to overtake (for example a MC on their side of road). This will cause a very specific front-to-front accident where the left corner of his car crashes with the left corner of second car (note: from the point of the view of the drivers in each car. His left, second car's left hits each other). This will cause a counterclockwise rotation (on those countries with right-hand traffic, in left hand traffic it will be a clockwise rotation when cars right hits the other car's right) of both cars. This would of course cause the ball to fling in a about 45 degree angle from the lever due to the centrifugal force AND deceleration force combined, thus the lever will NOT trigger. thats why BOTH the ball mechanism AND centrifugal mechanism is required. In some cases, the ball mechanism may even have a electromagnet or solenoid, or a rod connected to the pre-tensioner, that positively triggers the mechanism upon a accident detection. With "positive trigger", it means that the mechanism doesn't rely on weight, gravity or centrifugal force to trigger, but its simply a piece of material moved into the mechanism that will push the lever into the wheel, or a rod that moves into the central plate causing it to immidiately go out of position, so the mechanism can never false-negative during trigger (even if the mechanism can fail, for example broken solenoid, or the lever breaking off as shown in the video). And also about the belt tensioner, in those cars that use the brake pedal to detect a oncoming accident, they use a electric pre-tensioner in addition to the pyrotechnic one. The pyrotechnic one only triggers during a positive accident, which means usually a collision sensor must be deformed, so the car can be 100% sure its a accident and not just a hard brake.

Take a minute to appreciate the engineers, it takes a good amount of thinking for me to look at them and understand it but they came up with these out of nowhere

Very good explanation, thank you! Only thing I disagree is the pre-tentioners don't explode when braking hard but only when they detect actual crash. If it wasn't like that they would be activated all the time by car journalists testing the brakes :)

I like how accurate the make of the animation where the women keeps making accident with a static rock 😂😂😂

This was so clear and detailed, thank you

Hats off to you. Nicely demonstrated

So the pre tensioner only can work once? After the explosives that triggered the mechanism are used up and have to be manually reset?

The guys talking about how safe it is to have a seat belt and how they work but I don’t think it’s safe to not have a car door...

Wonderful explanation. You did a great work behind this video. Thank you so much for excellent and very important information....

Well explained and fully described new and old designs thanks for great information 👍👍

Please upload on 5g network technology

The animation around 1 minute is inverted :s The spring and axle don't act correspondingly

06:50 pushing breaks with left foot? What a driver :)

Never thought of the science behind seat belt. Thank you

can some one explain me 7:12 i understood the explosion part but what if a hard breaking saved the collision then shoul we replace the explosion piston each time after a emergency breaking

0:08 - pow right in that pretty face

Such an engaging way to explain the technology. Thanks.

One thing I learned from this video is you have to maintain your vehicle even if your car looks fine after the accident.

5:17 such high heels are not recommended while driving a car.!!!

I for one have complete confidence in all these little bits of plastic and metal that are loosely fitted together.

how did we even think about this! it's mind boggling!!

Thnx volvo for the seat belt +Why the f this woman used her left leg

If you can't avoid the giant boulder in the road then you shouldn't be driving.

Thanks for a another amazing video. Please don't be discouraged by some commentors writing non important things. The whole purpose of watching your educational videos to to gain knowledge. Knowledge is the key to success. But some people have nothing to learn, instead they are making comments like, "wheels were not spinning, or the lady driver, or no blood from the crash. PLEASE DO NOT BE DISCOURAGED BY PEOPLE MAKING THOSE KIND OF COMMENTS. These people don't realize that it takes lot of effort to make 3D models function in every aspect. My message To the public who are writing non important comments; Please try to understand the the main concept, not the unrelated stuff. I love your videos, please keep up with the great work. The more we learn, the better off we will be. This is what the internet is suppose to be for, not uploading personal photos on facebook and other social media. Please keep making amazing educational videos.

Thank you very much for all your kind information, beautiful explanation 👍

Last time I was so early seatbelt wasn't even a thing.

I'm doubting that my 2003 Corolla has half of these safety advancements lol. It's probably just a belt taped directly to the frame.

Wow, Very Nice Explanation!

Good explanation of how a seatbelt functions.

Just few months before survived an deadly accident...all thanks to seat belt and airbag

Poor lady how many times she has to involve in an accident and take damage to show us how seat belt work 😂😂😂

Wow! Nice. Good job man. 💚❤️💙

Kudos to the Engineers and Designers !!!

So wait, if I ever press the brake really fast, I've already used up that explosive thingy?

Here's a bonus 😉 , This entire process done within milliseconds.

That was interesting. Facts not fluff. Had never thought of the brake pedal being tied to the seatbelt. See you can learn something sitting in a car wash/spa on a summer Thursday afternoon.!!!!

@ 3:45 Favorite part! "LET'S give it an ORANGE color"!!

I can't be the only one who fears that the belt will snap or tear, right?

Feminist like: hell this channel is showing women as driver in accident ! ....

A complete video with relevant examples. Enjoyed a lot 5x5 stars 🥰🥰

awesome video with great presentation and explanation

Explosive pretensioner..? Does that mean it is a single use item, and needs to be replaced, even if the car is not damaged..?

Nobody is talking about the fact that there is no drivers door.

Behind each simple mechanism a genius ideas of engineering ✌🏼

Wowwwwww......super awesome....and what a amazing explanation...super thanks for sharing!

6:57 since she didn't step on the clutch, wouldn't this vigorous breaking stall her rare manual bmw real quick?

These shoes shouldn’t be recommended while driving 😉

thanks！谢谢作者！小小的安全带大大的人类智慧！

very well explained technology behind seatbelt & its operation

Step one: Actually get a car door