How Seatbelts work? Car Seat Belt

How Seatbelts work? Car Seat Belt

In this post, we will give you Info About How Seatbelts work? So Let’s Start – Everyone knows what happens in an accident if you don’t wear a seat belt. In slow motion, what you see in this accident seems really painful. Modern seat belts, on the other hand, smartly allow enough movement to avoid internal damage and enable you to land safely on an airbag in this article.

How-Seatbelts-work
How-Seatbelts-work

We won’t just learn how a seat belt works; we’ll also learn why modern seat belt mechanisms are designed the way they are. So buckle your seat belt and join us on a design journey. Let’s start with the most basic form of seat belt design, one that uses a spiral spring and seat belt webbing. The center of the spiral spring is connected to a freely rotating shaft, as shown.

How does the spring tense as you rotate the shaft?

How Seatbelts work
How Seatbelts work

We have just created a basic seat belt retractor using this arrangement because the webbing is also attached to the shaft when not in use the passenger lets the webbing go and the webbing will automatically windowing to the stress of the spring.

In this design, the other end of the webbing is fixed as shown, and a buckle clip is also kept in the webbing as shown. The passenger can simply clasp the seat belt, and it will fit perfectly. The retractor will release enough length of webbing depending on the passenger size.

Three Point Seat

How-Seatbelts-work
How-Seatbelts-work

The three points in this design are highlighted here. This design will not cause passenger discomfort by restricting movement. Obviously, the seat belt design will fail completely in an accident because it allows passenger movement even during an accident. An ideal seat belt mechanism should prevent passenger movement during an accident.

How to convert the current design into an intelligent seat belt mechanism?

How Seatbelts work
How Seatbelts work

A clever mechanism can be designed by taking advantage of this effect by using this free-to-roll steel ball and a hinge. The ball is placed on the other side of the retractor and a sprocket is connected to the retractor shaft. This means that whenever the belt winds or unwinds, the sprocket will spin under normal driving conditions.

How Seatbelts work
How Seatbelts work

However, if the vehicle comes to a rapid stop, the ball will slide forward owing to inertia, which will shift the hinge and trigger a locking mechanism, which will prevent the webbing from being released from the retractor.

The ball movement technology we just discussed is a perfect one, but a common man cannot test it, so engineers came up with an interesting idea to develop another mechanism that is based on t in the early days of seat belt development, it was quite important to win people’s trust so that they would use seat belts regularly in the early days of seat belt development, it was quite important to win people’s trust so that they would use seat belts regularly

How Seatbelts work
How Seatbelts work

This speed-based locking mechanism may be created with the help of a few new components. First, a central piece is attached to the webbing shaft and an internal gear is fixed to the frame by attaching it to the frame. A second piece rests over the central piece.

Let’s make it orange. The interesting thing is that the orange piece is not tightly fitted to the central piece; it is slightly loose and free to move as shown. If the central piece rotates slowly, the orange piece will be able to keep up; however, if the central piece rotates quickly, the orange piece will be unable to keep up, resulting in an interesting lock as shown.

How Seatbelts work
How Seatbelts work

For a better understanding, let’s watch the same animation in ultra slow motion. Obviously, the belt will lock when the passenger moves forward quickly. Most importantly, this is a simple mechanism that anyone can test, increasing consumer confidence in seat belt usage. This second mechanism has another use: if the first mechanism fails, it will act as a backup mechanism, but the issues related to seat belt usage will remain.

If a seat belt completely blocks passenger movement during an accident, the belt will exert tremendous pressure on the passenger’s chest, potentially causing internal organ injury. This risk is why modern seat belt retractors include a torsion bar. The torsion bar helps to release the belt a little when it reaches a critical load, preventing the passenger from experiencing excessive chest pressure.

three-point seat
three-point seat

How it is done practically the end of the seat belt webbing can be connected to this torsion bar?

The concept of this mechanism is simple: when the load on the belt reaches a critical limit, the bar will twist as shown. Please note that one end of the shaft is fixed due to the locking mechanism. Also, the twist of this bar is not uniform throughout its length; it is zero at one end and maximum at the other. If we connect the belt directly to this shaft, we will not get a belt releasable.

three-point seat
three-point seat

The belt webbing is connected to a spindle, which is connected to the free end of the torsion bar. This connection means that during torsion, the entire spindle will turn the torsion bar‘s maximum twist angle. This unit replaces the retractor’s normal shaft, allowing the belt to be released slightly.

Most of us sit in a car in a relaxed manner, So our bodies may not lean on the seat perfectly. This posture drastically reduces the amount of time the safety mechanisms have to save your life when the belt pressure reaches a critical value, saving the passenger from internal organ injury. Another ingenious safety mechanism common in cars nowadays is the pre-tensioner.

three-point seat
three-point seat

A pre-tensioner, on the other hand, forces you to sit as close to the seat as possible just before an accident. Most of us press the brake pedal hard right before an accident, and a smart controller predicts an accident by sensing the fast movement of the brake pedal. Retractors with pre-tensioners have an additional piston mechanism.

A pre-tensioner, on the other hand, forces you to sit as close to the seat as possible just before an accident. Most of us press the brake pedal hard right before an accident, and a smart controller predicts an accident by sensing the fast movement of the brake pedal. Retractors with pre-tensioners have an additional piston mechanism.

Don’t forget to buckle your seatbelt also don’t forget to share this post.

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