What are seatbelts/what do they do?
Seatbelts are a major safety feature in any vehicle and they are designed to significantly reduce the possibility of injury to driver and passengers in the event of a collision or sudden stop. There are many different types of seatbelt, the two-point, the lap, the sash, the multi-point child’s seatbelt, but the most common found in modern vehicles is the three-point seatbelt which consists of a strip of material or belt, anchored on three points around the seating position, that is placed over the chest and upper body and lap of the occupant.
Seatbelts can limit the danger of serious injury or even death by stopping the driver or occupants of the vehicle being thrown out of windows, windscreens or doors in the event of a collision. They will also aid in safe deployment of the airbag as they will keep the occupant in the correct position should this be activated. The correct wearing of seatbelts will protect the heads of drivers and passengers from injury through contact with the interior of the vehicle if a sudden stop should occur.
Getting into the details of seatbelts
Seatbelts are required by law for every seat in a vehicle whether they are front or rear-facing. The three-point seatbelt consists of a Y-shape configuration, a combination of the sash and lap belt that will effectively exert an opposite force to the body when the vehicle is stopped suddenly or brakes hard. The design of modern seatbelts allows for the driver or occupant to move freely in any direction in a normal manner but will arrest movement under a sustained and sudden force. This is achieved through the use of spring-loaded reels or retractors with inertia-locking mechanisms at the base of the door column and from where the main belt is coiled and uncoiled from. As the belt is pulled slowly from this point over the shoulders and upper body, a metal clip or tongue on the belt can be inserted into the seatbelt buckle which locks the whole system in place. The seatbelt buckles are located on the opposite side of the seat to the retractor in the front seats, and at the base of the backrest for the rear seats. In children’s seatbelts the layout is different with five points of contact with the seat. Here there are normally two shoulder straps which connect to a lap section and a belt between the legs.
Most modern vehicles now have automatic sensors which detect whether the seatbelts are being deployed and will portray a warning symbol on the dashboard and sound a beeping chime if they are not.
What if something goes wrong with a seatbelt?
The majority of faults regarding seatbelts are due to problems with the retractor system, either being stuck and not allowing the belt to unreel or not allowing it to be reeled back into its holder. The belts themselves may begin to tear or rip due to prolonged chafing and over-long usage. The seatbelt buckle may malfunction and not enable the tongue to insert correctly and be locked in place. Occasionally even though the seatbelt is worn correctly, the seatbelt sensor alarm will still chime due to an electrical fault.