@@belovedtruth3447 The pretensioner doesn't fire when you slam on the brakes, it fires with together with the airbags if the SRS detects a major impact. Just think about it this way, it's a pyrotechnic charge that yanks the belt tight. That mechanism and charge are single use, so if it fires when you slam the brakes (ie. before impact) you'll have to replace it after every emergency brake. In my experience the pretensioner is also not in the retractor, but part of the buckle on the side of the seat bottom. This also makes sense if you think about its purpose. The pretensioner is not there to take up slack at your shoulder, it's primarily there to take up slack from the lap section of the belt, so you don't slide under the seatbelt (known as submarining, and it causes MASSIVE internal injuries). If it yanks at the top, the friction at the buckle will interfere and it won't be nearly as effective. For this reason it yanks the buckle down. In a modern car, the inertia-based lock also operates in all directions, and it's farily sensitive. If the car experiences fast acceleration in any direction (so hard accelerating/braking, hard turning/swerving, rolling, etc) then the belt retractor locks, and will only unlock when you introduce slack by pushing yourself into the backrest. This serves two purposes. First it keeps you planted in your seat during aggressive maneuvers, and second it serves to "prime" the seatbelt in case the pretensioner needs to fire. If it only worked with the force of an accident, there would be a delay during which the belt freely unwinds before the mechanism can lock (keeping in mind how quickly an accident happens). Because of that the pretensioner would pull the belt out a bit further before the inertia lock has time to engage, which would drastically reduce its usefulness. But with the belt already locked the pretensioner will simply take up the slack.
@@belovedtruth3447 Yep, I was quite surprised that they got it that wrong. I suppose it can happen, but then they should take steps to correct the mistake.
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.
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.
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!!!
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.
@@IonorReasSpamGenerator Yes, there are also instances where flying out of a moving train has saved someone’s life, but generally it’s not a good idea. Same with just about every safety measure
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 🙏
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.
Correct, The pretensioners must be replaced or rebuilt after an accident. The video is mistaken about when they fire though, you cannot simply trigger the pretensioners by slamming on the brakes, they are fired when an impact is detected and/or the SRS module determines they are necessary.
H I T M A N CoC my guess is the explosives can create a lot more pressure much faster and more reliably than a compressed air feed. The car would need more equipment (air compressor and storage). I guess they did the math and figured it would be cheaper to replace explosives as needed than to include every car with a compressed air system.
@@JacobHutzler Let's face it, once a car is more than a few years old, if it gets in a wreck that deploys airbags/pretensioners, there's no need to replace them because the vehicle is likely a total loss at that point.
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.
i really confused with the combined effect of pretensioner and torsion bar, as torsion bar is provided to absorb rigidness from innitial impact to standstill of vehicle, so that passengers wont get much hard force. and allow them to fall forward to a rate that air bags will fully deploy. but using the pretensioner at the time of innitial impact is like countering the effect of torsion bar, one place enggineers are allowing seat belt to fall forward slightly, another case they are tightening it. please someone explain where i m wrong in my understanding of torsional bar n pretensioner
@@ashishkumar-yn5vm First, you want to hug hug the person, as much as you can. As tight as possible. First you have to overcome the fact that people just do not put the belt on properly, so it is not tighten to your hip and body, then you must overcome clothes that also have an impact of the tightness of the belt. Then you have to overcome people leaning out from the chair. So, pretension system and explosive devices try to fix all this (but YOU still should unzip thick coat(jacket and then buckle up and then tighten the belt so it is firmly in place). Then you crash and everything pull you into the seat as much as possible, because you should move as little as possible to start with. Then you have the flexing of the entire system to help you slow down in a controlled manner (if you have slack of the belt you will first just fly uncontrollably forward until the belt catches you and that is BAD) together with the deformation zones and then finishing with the airbag. To see what happens when the seat belt does not proved the correct holding force on you, look at crash tests of Tesla Model S. They failed twice(!) because of bad seatbelts. They redesigned the system between crash test 1 and 2. After crash test 2 Elon said that the test was faulty...........
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.
The problem with these wonderful life savers is user error. Aka people not wearing them. So anyone reading this, please remember to buckle up because you never know when it will save your life.
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.
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
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
Or a middle seat seat belt jammed because your station wagon rear seats fold down, shortening the length furthur while it down, so getting the seat back up leaves it permanantly jammed. This is for those middle seats with seat belt fitted into top of folding seat. Other ways it jams, is when you are at a intersection with a camber or slope sideways meaning seatbelt inadvertantly does it job, so you cannet lean forward for better view around parked cars. But I trust the seatbelt with my life, because it original design was simple, and if simple works, then it smart. Thank you Volvo for not patenting (or trademarking ?) the 3 point safety belt, but instead allowing other car manufactuers to use their design for all our safety.
When we haven't buckled the Seat Belt and see Police standing in front and when we try to suddenly pull the seat belt, it will lock. We end up paying Fine
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.
Weird that it needs such a oddly shaped plate. I thought it was going to be a simple ratchet that swings outwards due to centrifugal forces. Governors (devices for steam engine speed control, exploiting centrifugal force) predate cars.
Nice explanation, but I don't think pretensioners currently fire before impact. If they did, any hard braking could trigger them. I was a mechanic years ago and I would always do a maximum braking test before releasing a car to the customer. This is still a common practice, and would trigger pretensioners if brake forces alone were enough to do so. Honestly, unless you do autocross or racing, most likely your mechanic pushes your car harder than you ever will short of an emergency, and he does it to make sure that it will work correctly in such a case. I am fairly sure that seat belt pretensioners fire when it has been determined that ait bag deployment is likely, but the forces have not been acting long enough to move the occupants into the correct place for optimim airbag function. I take this from wrecks where the seatbelt pretensioners fire, but not the airbags. These are usually low speed crashes, or rear impact crashes.
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...
Cruise control is just a computer module that keeps your speed the same. Pretty much all modern cars use electronic throttle bodies so they can control them to keep the same speed. It’s really not that remarkable. Adaptive cruise just uses a radar sensor to keep you at a certain distance from the car in front
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
WOW that’s evolution of the seatbelt. Too fracking cool. I’m sure glad they’ll help you survive crash. Now, can I get one of those for my power chair? Air bags don’t seem to work on them...
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!
At 0:48 the shaft is rotating in the wrong direction to tension the spiral. Nevertheless this video explains the operation very well. Thanks for your effort!
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 :)
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.
Very good explained. But i have a question. The last part of explaining is that seatbelt fixes you into the right spot before crash, when you push the break pedal. But what if you dont push break pedal? Then seatbelt dont fixes you into the right spot on the seat? ... sometimes can happen, that passenger cant react in right time, because .. million reasons of course ... but this is a place to do an improvement and connect seatbelt system with the car senzors, which can recognize crash earlier than passenger. And if senzors recognize the crash earlier than passenger, then passenger can be fixed automatically. But... its just an idea. What you think? Can it works in reality?
Figured in an accident last week. Bumper ripped, hood popped, windshield shattered and air bags blown. And yup the seat belt worked well with pre tensioner. Really saved our lives.
i am from seat belt manufacturing company so let me tell you , pressing slow or fast the brake the explosion will not take place at any cost . Pressure / Force sensors will be place at the front end of the car only if the car get that enough pressure sensors will activate and pass the signal to MGG ( micro gas generator ) to ignite . I hope its clear now
Yep. If the airbags go off you need to replace the bags as well as the whole retractor assembly. But they won't just go off by stomping on the brakes you need to be in a collision.
@@wet0wl Well, yes... But I was also referring to where they are attached. The entire mechanism could come loose from the bolt that ties it to the seat or car...
I saw a video where they talked about an accident on a highway, happened at around 130 kph (80 mph) and they said there was so much energy released at the impact that the seatbelt just ripped.
@@benjaminrobledo5466 Well there's only so much seatbelts, airbags and crumple zones can protect you from. But if you pay attention you will brake and try to evade the obstruction so you hit it an angle. If you just run head on into something at full speed you will probably die even with all the safety features in place. So I don't think it's much cause for concern, seatbelts do their job fine but they also require the drivers to pay attention and follow the rules.
2:43 I know this from my childhood, but the ball can be moved from the seatbelt being tugged really fast even while the velocity of the vehicle is constant, right?
The three point seatbelt was invented or designed by volvo and they left it patent free so that every vehicle manufacturers can use it
@@tbird-z1r Nah I think this was the case.
& Then came the american capitalists
That is interesting
Yeah that's so kind of them ...
Another fun fact. Volvo is actually owned by china now
Hats off to this girl, she risked her life multiple times just to show us how seatbelts work.
She is Catwoman, she has 9 lives.
Yeah
She's so pretty! Is she single?
I saw a water bottle fly across the car 😂😂😂
It’s an animation. The woman is not real. She cannot die.
Crazy how much thought and engineering goes into aparently simple things
And then the people who explain it get the whole pretensioner thing wrong.
@@johannkuhn5685 alright, now you explain it then..
@@belovedtruth3447 The pretensioner doesn't fire when you slam on the brakes, it fires with together with the airbags if the SRS detects a major impact. Just think about it this way, it's a pyrotechnic charge that yanks the belt tight. That mechanism and charge are single use, so if it fires when you slam the brakes (ie. before impact) you'll have to replace it after every emergency brake.
In my experience the pretensioner is also not in the retractor, but part of the buckle on the side of the seat bottom. This also makes sense if you think about its purpose. The pretensioner is not there to take up slack at your shoulder, it's primarily there to take up slack from the lap section of the belt, so you don't slide under the seatbelt (known as submarining, and it causes MASSIVE internal injuries). If it yanks at the top, the friction at the buckle will interfere and it won't be nearly as effective. For this reason it yanks the buckle down.
In a modern car, the inertia-based lock also operates in all directions, and it's farily sensitive. If the car experiences fast acceleration in any direction (so hard accelerating/braking, hard turning/swerving, rolling, etc) then the belt retractor locks, and will only unlock when you introduce slack by pushing yourself into the backrest. This serves two purposes. First it keeps you planted in your seat during aggressive maneuvers, and second it serves to "prime" the seatbelt in case the pretensioner needs to fire. If it only worked with the force of an accident, there would be a delay during which the belt freely unwinds before the mechanism can lock (keeping in mind how quickly an accident happens). Because of that the pretensioner would pull the belt out a bit further before the inertia lock has time to engage, which would drastically reduce its usefulness. But with the belt already locked the pretensioner will simply take up the slack.
@@johannkuhn5685 Wow, that's a good read. Thanks. They should've done more research i guess!
@@belovedtruth3447 Yep, I was quite surprised that they got it that wrong. I suppose it can happen, but then they should take steps to correct the mistake.
Very well explained. Nice job!
Ya
Hi Arvin Ash
Hi
Hey, when are you going to tell why Speed of Light is what it is??
@@crewrangergaming9582 i dont think thay they would see this message of yours. Try asking in another video?
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.
Yeah, I wrote a comment on that too.
I think 80% won’t read this
@@ilovehuhnchen1956 I didn't read cause it looks shit waste of time
@@ilovehuhnchen1956 too much to read
@@mohankrishna1443 Your loss
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.
I was thinking about this, thanks for the explanation.
I have floored the brakes several times by now and I thought maybe my pretensioner has fired!
My VW and my parents merc both pretention even without airbags going off and have done so multiple times, so they can’t be charge based systems there.
All true,but my 1999 is not connected to any electrical,works from ball action only
I was thinking about this.... thanks for clearing my doubt.
why do people not make the pretensioner multi usable?
she really didn't see that boulder in the road tho?
She didn't have a door either
She's a woman, what do you expect?
@@SackbotNinja03 ahhh I didn't notice the missing door
@@1schwererziehbar1 bruh noooo, don't be sexist!!! for real
@@1schwererziehbar1 this seems logical bruh
Is no one gonna talk about how much accidents she went in for us
Yeah, new workers usually struggle more
We'll remember her sacrifice.
@@risingredstone5949 we should start a religion in her name.
@@andrewtran4564 Safetyeism
@@andrewtran4564 why you invent religion everyday
Don't you hate it when there's a massive boulder in the middle of the road
when you missunderstand field with road😹
It sometimes happens when you live in the Rocky Mountains.
@@prestondeters5093 also happens when while e coyote drops a rock on the road
@@patman817 Stop picking on Brave Wilderness!
No
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!!!
7 Years ago was 2015, there HowStuffWorks explains it all in an article on their site form 2002
@@Chris-rg6nm 7 years ago from the time he had posted this comment was probably 2013 or 2014, not 2015.
@@somebody_2837 Thats still past 2002
@@Chris-rg6nm Correct, but I was just saying.
She's braking with her left foot...
Its self-explanatory... See your first word😂
Harsh Madnani haha sexism 🤣🤣
She's probably a pro rallye driver
ZOMBIE GUT kill but u have to move foot from your gas pedal
That is a clutch pedal on the left...
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.
sorry to hear that. please make sure you pass this message inperson as well
There are instances where not wearing a seatbelt saved lives, but sure, on average you are much better off using them...
@@IonorReasSpamGenerator
Yes, there are also instances where flying out of a moving train has saved someone’s life, but generally it’s not a good idea. Same with just about every safety measure
But he had his freedumb.
@@IonorReasSpamGenerator good thing people can pick what kind of accident they want
Really loved that illustration. Thanks to make easy understanding, how seatbelt is most important.
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 🙏
Finally we got a new girl to drive your cars.
🤣🤣
But she's more creepier
The other one died. No seat belt.
@@adhirajjadhav7918 really? thought she's pretty
And she should never wear high heels for driving.
it is hands down the best channel on UA-cam! Every video I watch makes me feel 10 times smarter
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.
😂😂😂😂😛😛😜🤪 u got cool humor man
This is one of the best channels on UA-cam! Congrats from Brasil!
So the pre tensioner only can work once? After the explosives that triggered the mechanism are used up and have to be manually reset?
Correct, The pretensioners must be replaced or rebuilt after an accident. The video is mistaken about when they fire though, you cannot simply trigger the pretensioners by slamming on the brakes, they are fired when an impact is detected and/or the SRS module determines they are necessary.
Wouldnt IT be better if The pre tensioner worked on air, like when you brake hard suddenly instead of explosive?
@@soldieroflife6487 A separate pneumatic assembly would be required also pneumatic has kinda sluggish response so pneumatic would defeat the purpose.
H I T M A N CoC my guess is the explosives can create a lot more pressure much faster and more reliably than a compressed air feed. The car would need more equipment (air compressor and storage). I guess they did the math and figured it would be cheaper to replace explosives as needed than to include every car with a compressed air system.
@@JacobHutzler Let's face it, once a car is more than a few years old, if it gets in a wreck that deploys airbags/pretensioners, there's no need to replace them because the vehicle is likely a total loss at that point.
Never in my lifetime would I figure out how to design something as simple as this
I'm with you on that one!
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.
Produced by Autoliv :)
i really confused with the combined effect of pretensioner and torsion bar, as torsion bar is provided to absorb rigidness from innitial impact to standstill of vehicle, so that passengers wont get much hard force. and allow them to fall forward to a rate that air bags will fully deploy. but using the pretensioner at the time of innitial impact is like countering the effect of torsion bar, one place enggineers are allowing seat belt to fall forward slightly, another case they are tightening it. please someone explain where i m wrong in my understanding of torsional bar n pretensioner
@@ashishkumar-yn5vm First, you want to hug hug the person, as much as you can. As tight as possible. First you have to overcome the fact that people just do not put the belt on properly, so it is not tighten to your hip and body, then you must overcome clothes that also have an impact of the tightness of the belt. Then you have to overcome people leaning out from the chair.
So, pretension system and explosive devices try to fix all this (but YOU still should unzip thick coat(jacket and then buckle up and then tighten the belt so it is firmly in place).
Then you crash and everything pull you into the seat as much as possible, because you should move as little as possible to start with. Then you have the flexing of the entire system to help you slow down in a controlled manner (if you have slack of the belt you will first just fly uncontrollably forward until the belt catches you and that is BAD) together with the deformation zones and then finishing with the airbag.
To see what happens when the seat belt does not proved the correct holding force on you, look at crash tests of Tesla Model S. They failed twice(!) because of bad seatbelts. They redesigned the system between crash test 1 and 2. After crash test 2 Elon said that the test was faulty...........
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.
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.
Plus she is using the left foot to brake. She would not had passed her driving text IRL.
She is alexa, i think.
Nobody notice the door is gone
What's a dead pedal? Oh, noob drivers' resting place?
you're all wrong thats a manual car and the left foot is on the clutch pedal, which needed to get pushed down everytime you brake
The problem with these wonderful life savers is user error. Aka people not wearing them. So anyone reading this, please remember to buckle up because you never know when it will save your life.
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.
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
I bet a lot of those pre-tensioners out there are already exploded, since people may have braked hard in non-accident situations...
No, Without ECU detection on crash it won't fire
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
Anyone else’s seatbelt lock up sometimes when your not doing anything
Like breaking at a T crossing and leaning forward to see crossing traffic? Yes.
Proto Man 😂
Or a middle seat seat belt jammed because your station wagon rear seats fold down, shortening the length furthur while it down, so getting the seat back up leaves it permanantly jammed. This is for those middle seats with seat belt fitted into top of folding seat. Other ways it jams, is when you are at a intersection with a camber or slope sideways meaning seatbelt inadvertantly does it job, so you cannet lean forward for better view around parked cars. But I trust the seatbelt with my life, because it original design was simple, and if simple works, then it smart. Thank you Volvo for not patenting (or trademarking ?) the 3 point safety belt, but instead allowing other car manufactuers to use their design for all our safety.
Yep my 2016 Sonata.
When we haven't buckled the Seat Belt and see Police standing in front and when we try to suddenly pull the seat belt, it will lock. We end up paying Fine
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.
Mr seatbelt expert here 🙄☝️
The ball bearing is absolutely ingenious! Simplicity at its finest.
شرح في منتهى الروعه والضوح
Who tf invented that orange mechanism! That some genius right there I always wanted to know how that works
Weird that it needs such a oddly shaped plate. I thought it was going to be a simple ratchet that swings outwards due to centrifugal forces. Governors (devices for steam engine speed control, exploiting centrifugal force) predate cars.
Nice explanation, but I don't think pretensioners currently fire before impact. If they did, any hard braking could trigger them. I was a mechanic years ago and I would always do a maximum braking test before releasing a car to the customer. This is still a common practice, and would trigger pretensioners if brake forces alone were enough to do so. Honestly, unless you do autocross or racing, most likely your mechanic pushes your car harder than you ever will short of an emergency, and he does it to make sure that it will work correctly in such a case. I am fairly sure that seat belt pretensioners fire when it has been determined that ait bag deployment is likely, but the forces have not been acting long enough to move the occupants into the correct place for optimim airbag function. I take this from wrecks where the seatbelt pretensioners fire, but not the airbags. These are usually low speed crashes, or rear impact crashes.
So the pretensioners fire because the air bag sensors and not by the brake pedal, but in some cases the air bags are not actived?
Incredible engineering design, the developer were appreciated.
Think you alot for this explanation! Could I know how you simulated the scene? Which simulation software you
use?
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...
kudos to this team.......that was an awesome explanation with nice CG,showing all version of seat belt mechanism...
Simple yet intelligently put together for anyone to understand with amazingly simple visuals so we can follow along. Bravo
This is the best explanation I found on the internet!
Very interesting, hope to see more of this type of videos.
Wowwwwww......super awesome....and what a amazing explanation...super thanks for sharing!
Please make a video on "How *Hill climb assist* works in car?" Or "How *cruise control feature* works in the car?"
Also traction control, please
Cruise control is just a computer module that keeps your speed the same. Pretty much all modern cars use electronic throttle bodies so they can control them to keep the same speed. It’s really not that remarkable. Adaptive cruise just uses a radar sensor to keep you at a certain distance from the car in front
thanks！谢谢作者！小小的安全带大大的人类智慧！
That women has been through a lot of crashes creds for her
wow this is the best explanation you can get. Thanks!
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
Pretty sure the pretensioner doesn't trigger with hard braking, it triggers on collision
Well explained and fully described new and old designs thanks for great information 👍👍
so much thought into something as "simple" as a seat belt...awesome vid
WOW that’s evolution of the seatbelt. Too fracking cool. I’m sure glad they’ll help you survive crash. Now, can I get one of those for my power chair? Air bags don’t seem to work on them...
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!
Good work
Wich kind of software used to animate the whole video ?
🤔 BMW refuses to use a driver door, but made a genius technology to safe the computer girl
Also they didn't install ABS. Look at the wheel it's get locked up
@@a_r_u_n7595 And front wheel isn't balanced.
Computer girl fine
This is fabulous Sir thanks and continue teaching us
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!
awesome video with great presentation and explanation
Imagine someone rips your seatbelt off and your door only to explain how a seatbelt works while your about to crash into a boulder 💀💀💀
At 0:48 the shaft is rotating in the wrong direction to tension the spiral.
Nevertheless this video explains the operation very well.
Thanks for your effort!
This is amazing. I was surprised that a lot of mechanisms (more than I thought) are used in seat belt. Thank you a lot!!!
So beautiful learning video. Thank you very much for sharing.
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 :)
Wow, Very Nice Explanation!
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.
Very good explained. But i have a question. The last part of explaining is that seatbelt fixes you into the right spot before crash, when you push the break pedal. But what if you dont push break pedal? Then seatbelt dont fixes you into the right spot on the seat? ... sometimes can happen, that passenger cant react in right time, because .. million reasons of course ... but this is a place to do an improvement and connect seatbelt system with the car senzors, which can recognize crash earlier than passenger. And if senzors recognize the crash earlier than passenger, then passenger can be fixed automatically. But... its just an idea. What you think? Can it works in reality?
1:36 “Wont Cause Passenger Discomfort”
Me: You know what will? THE FACT THE CAR HAS NO DOOR
Nice explanation sir.good job.hats off.❤❤❤❤
not gunna lie tho that animation girl is kinda cute
deathtoy101 I won’t be surprise if the author also create +18 content for other projects or hobby.
Ángel hahaha
Ángel I need a link to that for educational purposes of course
Before crash: That's my new girlfriend.
After crashing into the same boulder 3 timed : IT'S JUST THAT I THINK WE SHOULD SEE OTHER PEOPLE
Name?
Such an engaging way to explain the technology. Thanks.
The animation around 1 minute is inverted :s The spring and axle don't act correspondingly
You're right! Thanks!!
Figured in an accident last week. Bumper ripped, hood popped, windshield shattered and air bags blown. And yup the seat belt worked well with pre tensioner. Really saved our lives.
7:39 she just disappeared with her car lol
Great explanation and animation😊😊🙏
5:17 such high heels are not recommended while driving a car.!!!
Thank you
Good observation
and we can see result of
Yeah, but also it's not recommended to drive on a road with a big rock in the middle.
Unless you're driving a Ford Probe
this channel is very really informative.
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...
Wow...this was very much informative and was beautiful explained. 👍👍
So wait, if I ever press the brake really fast, I've already used up that explosive thingy?
Follow
No that part isn't true
i am from seat belt manufacturing company so let me tell you , pressing slow or fast the brake the explosion will not take place at any cost . Pressure / Force sensors will be place at the front end of the car only if the car get that enough pressure sensors will activate and pass the signal to MGG ( micro gas generator ) to ignite . I hope its clear now
@@ravikumartantry Yeah that makes more sense. Thanks.
Wonderful explanation. You did a great work behind this video. Thank you so much for excellent and very important information....
One thing I learned from this video is you have to maintain your vehicle even if your car looks fine after the accident.
Waw! Never knew how such mechanism work before!
Can you now explain to us how does the *Contimuum Transfunctioner* work?
I like how accurate the make of the animation where the women keeps making accident with a static rock 😂😂😂
Very good information, i feel like am back to school. Excellent lesson.
Please upload on 5g network technology
Yes, and why it causes the corona virus, pleeeeeease
@@PlayboyHZ wait what?🤣
@@PlayboyHZ the cure for corona is easy.
place cell phone in microwave.
now you have a 5g corona cure.
ua-cam.com/video/g-gGeAe-PJA/v-deo.html
Much more awesome than I first thought
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.
yyyui9ii
Good explanation of how a seatbelt functions.
Explosive pretensioner..?
Does that mean it is a single use item, and needs to be replaced, even if the car is not damaged..?
Yep. If the airbags go off you need to replace the bags as well as the whole retractor assembly. But they won't just go off by stomping on the brakes you need to be in a collision.
Good Explanation..Expecting more information like this👍👍👍
If you can't avoid the giant boulder in the road then you shouldn't be driving.
Complex problem...Ingenuine solution...awesome
Here's a bonus 😉 ,
This entire process done within milliseconds.
Never thought that, so much engineering is behind the car seat belts. Thank you for the detailed video.
0:08 - pow right in that pretty face
Благодарим ви!
I can't be the only one who fears that the belt will snap or tear, right?
I never feared that just because of how strong seatbelts are, those things are actually insane
@@wet0wl
Well, yes... But I was also referring to where they are attached.
The entire mechanism could come loose from the bolt that ties it to the seat or car...
I saw a video where they talked about an accident on a highway, happened at around 130 kph (80 mph) and they said there was so much energy released at the impact that the seatbelt just ripped.
@@tabushka292
That's... Another concern I now have... 😂
@@benjaminrobledo5466 Well there's only so much seatbelts, airbags and crumple zones can protect you from. But if you pay attention you will brake and try to evade the obstruction so you hit it an angle. If you just run head on into something at full speed you will probably die even with all the safety features in place. So I don't think it's much cause for concern, seatbelts do their job fine but they also require the drivers to pay attention and follow the rules.
2:43 I know this from my childhood, but the ball can be moved from the seatbelt being tugged really fast even while the velocity of the vehicle is constant, right?
Just few months before survived an deadly accident...all thanks to seat belt and airbag
Hats off to you. Nicely demonstrated
Thnx volvo for the seat belt
+Why the f this woman used her left leg
6:57 since she didn't step on the clutch, wouldn't this vigorous breaking stall her rare manual bmw real quick?