Introduction To Passive Safety: Introduction: Seatbelts

Of all of the safety innovations brought forth by the automotive industry, the safety belt is universally recognized as the single most effective safety device. Specifically, the 3-point safety belt provides passengers with safety as well as comfort.

The effectiveness of the 3-point seat belt depends upon the correct positioning of the safety belt on the body.

Fig 1: Identifying Seat Belt Depends Correct Position Of Safety Belt On Body

Courtesy of BMW OF NORTH AMERICA, INC.

BMW safety belt systems use an upper anchor point which is height adjustable. In addition, the tensioning mechanisms allow the belt to remain relatively slack to increase comfort while driving.

The seat belt tensioning device is designed to remove slack in the seatbelt during an impact. This increases the effectiveness of the seatbelt and reduces the bio-mechanical load on the passenger.

There are 4 different belt tensioning systems which have been in use on BMW vehicles.

The 4 systems are as follows:

• Pyrotechnic automatic tensioners/end fitting tensioners
• Mechanical seat belt tensioners
• Pyrotechnic seat belt tensioners
• SGS (Seat Integrated Belt System)

More information on the seat belt tensioning systems will be covered in the forthcoming training modules.

Fig 2: Identifying Mechanical Seat Belt Tensioners

Courtesy of BMW OF NORTH AMERICA, INC.