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Car seat belt device

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Car seat belt device
Car seat belt device

Modern technologies are developing rapidly. However, invented more than a hundred years ago, the car seat belt has been a reliable means of protecting passengers and the driver of a car for more than a decade.

This simple device has saved millions of lives. According to statistics, 70% of the lives saved in car accidents are due to wearing a seat belt. Proper use of this device reduces the chance of injury in an accident.

Reliable belt

Types of belts

During the existence of this simple device, many different designs have appeared. According to their features, seat belts are divided into five types:

  • Two-point.
  • Three-point.
  • Four-point.
  • Five-dot.
  • Six-point.

Today, three-point seat belts are installed in modern cars. Invented by Niels Bohlin, they have been faithfully guarding our security for half a century.

Niels Bohlin made this invention when he was developing a safety system for aircraft catapults. On his initiative, the first seat beltsdesigns were installed on Volvo cars back in 1959. The popularity of these belts is easily explained: thanks to the V-shaped arrangement, in a collision, an optimal distribution of the energy of the moving body to the chest, pelvis and shoulders is achieved.

The Be alt-In-Seat design is considered a well-known modification of the three-point belt. In this design, the shoulder part of the latch is attached to the back of the car seat. Mersedes was the first to try this technology and introduce it into mass production 28 years ago.

Some say that Belt-In-Seat technology helps to avoid injury when a car rolls over.

Two-point seat belts were first put into service back in 1949. However, they appeared much earlier - more than a hundred years ago. In those days, the belts were devoid of any aesthetics, and they were replaced by an ordinary rope, which the drivers stretched across the belt.

In modern cars, two-point seat belts can only be found in the rear seats or in older models.

Four-point seat belts are used in sports cars. There is little comfort, but safety is greatly increased, which is a very important factor. Also, the downside is that these belts require top mounts, which further reduces the comfort of using belts of this type.

Five-point and six-point safety harness is a set consisting of many straps. They practically do not differ from each other. They are used mainly in aviation and in child seats. The six point harness hasadditional seat belt that goes over the legs.

Belt lining


The design of the seat belt is both simple and reliable:

  • Straps.
  • Castle.
  • Mounting bolts.
  • Retractor.

Webbing is most often made from synthetic materials. Thanks to this, the strength to which everyone is accustomed is achieved. The retractor in the design works on the basis of a ratchet mechanism. It serves to fully or partially retract the seat belt strap. Emergency blocking of the device occurs with the help of a special sensitive element.

An interesting fact is that the sensing element is based on an ordinary metal ball, which, when shifted, fixes the coil with a special system of levers. Sometimes a pendulum is used instead of a ball.

The seat belt buckle is a device that locks the belt holder tab. By pressing the lock button, you can quickly unfasten the belt.

The belt tension system deserves special attention. This happens thanks to a special flywheel, which is mounted on the axis of the coil. It usually looks like a small disk. In the event of an accident, a jerk is formed. The disc, according to the laws of physics, overcomes the force of friction. Parallel to this process, pressure arises on the helical surface.

Bolts in the design of the front seat belts also play an important role. They provide reliable fastening of the entire structure. As a rule, theymounted directly to the vehicle frame for maximum durability.

Safety belt

Operating Rules

To use seat belts effectively, it is important to know a few simple rules:

  1. Do not overtighten the belt, as this increases the risk of serious injury in an accident.
  2. Too little tension is also unacceptable, as in this case the braking effect of the seat belt is weakened. You can check the tension and make the correct adjustment in a simple way: you need to put your hand under the belt. If you feel a noticeable squeeze on the brush, then it is set correctly.
  3. Make sure that the harness is not twisted! In addition to making it uncomfortable to drive, it can also lead to a lack of fixation.
  4. Few people know, but after an accident, the fixation devices must be completely replaced, since the tape loses its useful properties, including strength, under strong tension. Also, according to the operating rules, every 5-10 years it is necessary to carry out a complete replacement of seat belts due to natural wear.
Disassembled seat belt

Sharing seat belts and airbags

In addition to the element we are considering, pillows play an important role in safety. However, the latter without belts have an almost useless effect. If during the accident the driver ignored the fastening, then the airbags simply may not work. Also, pillows, when opened, are capable ofcause serious harm to your he alth - in a collision, the impact will not be softened by fastened seat belts. This could result in serious injury. Therefore, the use of airbags is effective when seat belts are fastened.


The use of seat belts while traveling gives a fairly high degree of safety - almost 70% in world statistics. Airbags are significantly inferior to these indicators. According to the same statistics, pillows are only 20% effective.

It is very important that seat belts are worn by all passengers, even those in the back. After all, no one is safe from accidents. Fastened seat belts will allow all passengers to remain in a fixed position during an accident, and not randomly move around the cabin, harming not only themselves, but also other passengers.

Despite the three-point design being the most common, engineers from leading automotive companies regularly provide safety innovations.

Belt latch

Inflatable belt

Recently, a prototype inflatable belt was presented to the general public. Its principle of operation is very simple. In the event of an accident, the belt chamber is filled with air, thereby increasing the usable area, minimizing the risk of serious damage. The authors of this technology claim that this design is able to provide protection even in a side impact.

Volvo also announced its work in this area - the seat belt "cross-crosswise".

When turning over the car, the 3 + 2 technology announced by Autoliv will protect against significant injuries.


Remember that even the most perfect system can fail and is not able to guarantee one hundred percent protection. At speeds over 200 km/h, seat belts can be completely useless! Therefore, follow the rules of the road, be mutually polite on the road. Never ignore standard security measures!

Animal harness

Which seat belts to choose, everyone decides for himself. If you follow the simple rules that are described in this article, you can save the life of not only yourself, but also those who are in the car with you. And it doesn't matter if you use seat belts in VAZ or Mersedes cars, sometimes your life depends only on compliance with traffic rules.

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