Everybody knows what happens in an accident if you don’t wear a seatbelt. Do you know how a seat belt works? Modern seatbelts are not just a mechanism that arrests your motion. Rather they stop the movement to minimize internal injuries. It help you land safely on an airbag.
WORKING OF A SEATBELT
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Do you know how a seat belt works? the evolution of the seat belt mechanism is explained here,
3 POINT DESIGN
The basic design of a seatbelt is the simplest. This is a design using a spiral spring and seatbelt webbing. The center of the spiral spring connects to a freely rotating shaft. The spring tense when it rotates. The webbing is also connected to the shaft. Using this arrangement a 3 point seatbelt mechanism is built. This model does not cause any distraction to the passengers. This model completely fails in an accident. Because it allows the complete movement of passengers even in accidents.
During an accident, the vehicle experiences a huge deceleration. A clever mechanism can be designed by using this mechanism. By using a steel ball at the end. Whenever the belt winds or unwinds the sprocket will spin. When the vehicle stop suddenly, the ball moves up because of inertia. It makes a locking mechanism. It stops the release of webbing. Simply, the seatbelt arrest your motion during a crash.
LOCKING BASED ON WEBBING SPEED
If the webbing moves fast it should lock, if not it shouldn’t lock. It can be achieved with the help of a few new components. A central piece is connected to the center of the rotating shaft. An internal gear is fixed by attaching to it. Another piece sits over the central piece. If the central piece rotates slowly, the attached piece rotates with it. When the central piece rotates fast, it can’t reach with it, results in the lock. The belt will lock when the passenger moves fast.
The problem is the belt will cause damage to the passengers’ chest while stopping. It can lead to internal injury.
PRESSURE REDUCING MODEL
A torsion bar also added to the existing model. The end of the seat belt webbing is connected to the torsion bar. It helps to release the belt a little when it reaches a critical time. Save the passenger from excessive pressure on the chest.
Most of us sit car in a relaxed way. This posture reduces the work of the safety mechanisms. A pre-tensioner helps you to sit close to the seat. An additional piston mechanism also added with it. It filled with explosive materials. It will push the piston and seatbelt during the accident.