Seat belt: device and attachment

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

Modern cars are distinguished by a huge number of security systems. So, electronics allows you not to lose control over the car in the event of an emergency (skidding, emergency braking, and so on). But not all situations can be avoided. Therefore, in the event that a collision occurs, passive safety elements are implemented in the car. One of these is the belt. What is it and what types are there? Consider in our today's article.

Characteristic

Belts are the most common element of passive safety. Their main task is to prevent the movement of a person in the event of an accident. The use of a seat belt reduces the risk of injury in a collision, and significantly eliminates the possibility of hitting hard parts of the body and glass.

Few people know, but belts appeared on cars at the beginning of the 20th century. This system "migrated" to cars from aviation. However, at that time it was only available as an option. The most widespread seat belt received after the 50s. And in the USSR, such systems began to appear only with the advent of the Zhiguli. Belt installationsafety is carried out by the factory itself, at the stage of car assembly. Also, the owners are engaged in the installation of so-called sports belts. But more on that later.

About design

The main element of the seat belt is the tape. It is made of dense polyester fibers. Such material is able to withstand significant loads and does not tear. The tape forms a kind of webbing that keeps the driver and passengers in a given position and prevents the risk of displacement in the event of an accident. There are many examples of how unfastened people hit the glass and simply flew out of the cabin. The use of a belt allows you to securely fix the body and prevent accidents.

Also included in the design:

• Castle.
• Limiters.
• Belt attachment points. They may or may not be regulated.
• Inertial coils.
• Seat belt pretensioner.

These elements differ only in the number of attachment points. However, injury safety depends on this factor. Below we will look at what types of seat belts are.

Two-Point

These are the very first systems that appeared in cars. However, they can still be found today. As a rule, such belts are used for the middle passenger in the back row. The disadvantage of this system is that the length of the tape is not adjustable. Because of this, you have to use a seat belt extension. It is sold separately and costs about $25.

This type of belt runs in the passenger's waist area, across the seat. From a security point of view, such a system is ineffective. After all, it holds the body only in the lumbar zone. In a frontal impact, a part of the body will be loose and move forward. The stronger the collision, the greater the risk of spinal injury.

Three-points

This is a more modern look, which is used on both the driver's and passenger's seats. The system provides three fixation points, among which one (the one closer to the top of the rack) has the ability to adjust in height.

The lower part is equipped with a tape reel. This scheme provides a secure fixation of the body. Fixation is performed on the chest and in the lumbar zone. At the same time, the belt does not restrict movements and is very convenient to use. It is enough to lay it down and fix it at one point on the latch.

Four-point seat belt

These are the sports options we talked about earlier. The design is used on cars that participate in rallies and circuit races. From a security point of view, they are the best option. But why is the four-point seat belt so little used? All because of the specifics of use. To fix all the mechanisms, you have to spend a lot of time. In everyday use, this is not necessary, and the three-point ones do their job quite well.

Note that fixation optionsmay be different. But the most popular is two straps with one-piece fastening and one in the lumbar zone. The advantage of this scheme is that the vertical tapes are attached directly to the seat, and not to the body.

To use such a belt, you must first put the vertical elements on your shoulders (similar to putting on a backpack), and then stretch the lumbar and fix it on the latch.

There are also schemes where the vertical tapes can be detached. To do this, there is an additional lock and tongues at the ends.

Attachment for seat belt

It can be different. If we take into account the majority of cars, fasteners are carried out on body elements. Such a scheme is used in order to ensure that upon impact (when the maximum load is placed on the mechanisms), the tape does not fly off the attachment points. If the fasteners were on a regular seat, it could simply be pulled out. But why is such a scheme practiced on sports chairs? The fact is that the seat itself has a much greater rigidity and all attachment points are pre-calculated for deformation and stretching.

We also note that trucks use a special tape installation scheme. Here the belt is pulled out of the seatback.

This is done so that the tape does not go up and down on bumps, as the chair has a separate air suspension. Often this design is used on large buses and main tractors. However, do not assume that it is unreliable. At the factory, engineers carefully calculate these pointsfasteners, so it's safe to say that these belts are very reliable and safe.

How does it work?

We will take three-point systems as a basis, since they are the most common. So, after getting into the car, the driver pulls out the tape and fixes the tongue in the lock. Further, the inertial coil automatically removes excess. In the event of a collision, the sensors will activate the pretensioner. As a result, the strap will stretch. If the blow intensifies, the torsion bar will come into play. He gradually increases the length of the belt in order to reduce the pressing force on the body. Also note that the belt material itself is stretched upon impact. Despite the density, polyester can lengthen by hundredths of a centimeter. This will soften the momentum.

On old belts (without pretensioners), the reel performs the function of holding a person. With a sharp acceleration of the body, it is blocked. And then the torsion bar is already activated.

Conclusion

So, we found out what a seat belt is and what types it is. Finally, we note that after a significant impact, belts cannot be reused. After all, the material is stretched and is no longer able to withstand such a load.