Major Components of a Seatbelt - 1

1. Lap Belt or Webbing

   A typical seat belt consists of a lap belt, which rests over your pelvis, and a shoulder and extends across your chest. The two belt sections are tightly secured to the frame of the car in order to hold passengers in their seats. When the belt is worn correctly, it will apply most of the stopping force to the rib cage and the pelvis. Since the belts extend across a wide section of your body, the force isn't concentrated in a small area, so it can't do as much damage. Additionally, the seat belt webbing is made of more flexible material than the dashboard or windshield. It stretches a little bit, which means the stop isn't quite so abrupt.

2. Retractor

   The belt webbing is connected to a retractor mechanism. The central element in the retractor is a spool, which is attached to one end of the webbing. Inside the retractor, a spring applies a rotation force, or torque, to the spool. This works to rotate the spool so it winds up any loose webbing. If you release the webbing, the spring will tighten up, rotating the spool clockwise until there is no slacker in the belt. The retractor has a locking mechanism that stops the spool from rotating when the car is involved in a collision.