Collision Repair Training | United States
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Current Events/News: Advantage Online: 2005 Archives
WHIPLASH INJURY PROTECTION INNOVATIONS
May 31, 2005 - According to the National Highway Traffic Safety Administration (NHTSA), there are an estimated 272,000 whiplash injuries every year from rear-end collisions in the United States. The Insurance Bureau of Canada estimates that rear-end collisions account for 80% of whiplash and other soft tissue injuries in Canada. Many of these collisions are at low speeds. Advancements in safety systems to help prevent neck whiplash injuries from rear collisions are primarily being seen in European vehicles. This is because of a tough European standard called the Economic Commission for Europe (ECE) Regulation 25. ECE 25 requires head restraints for rear collisions. There are also strict standards for protection of front seat occupants, including tighter restrictions for front seat head restraints than are currently in place in North America. A proposed update to Federal Motor Vehicle Safety Standard (FMVSS) 202 increases the requirements for head restraints on North American vehicles. Even though it was drafted in 2000, NHTSA is still working on the Final Rule for the update. ECE 25 has inspired such innovations as the Volvo Whiplash Head Impact Protection System (WHIPS), a pendulum-type Active Head Restraint System by Saab, Audi, and GM, a spring-activated system by Mercedes-Benz, and a pyrotechnic active head restraint system used on the BMW 7 Series. This article discusses each of these systems, and the limited repairs that are allowed. WHIPS
Jaguar uses a similar system, but the Volvo WHIPS is unique in that there are replacement parts available to service a portion of the WHIPS mechanism. This can supplant the need to replace the full mechanism and seatback. The deformation link, return spring, and other parts are contained in a replacement parts kit from Volvo. When servicing, these parts require replacement on both sides of the seat. The kit includes both sides (see Figure 3). There is a specific inspection procedure after a rear collision that is detailed in the Volvo service information. This inspection procedure involves leaning the front seatback either all the way forward or backward (depending on the model), and inspecting an indicator pin or bracket. If the indicator shows that the link has deformed and there is no other damage, the replacement kit may be used. Jaguar requires closely inspecting the deformation link. If the link has deformed, the entire whiplash mechanism on each side and the seatback must be replaced. Pendulum System The whiplash protection system used on Saab and Audi vehicles is a mechanical pendulum (see Figure 4). When the occupant moves rearward (back and into the seat), their torso pushes against a plate that moves the head restraint upward and forward. This reduces the distance between the occupant’s head, and the head restraint, along with providing support and reducing injury to the occupant’s head. Springs in the seat structure return the head restraint to its normal position after the collision. Along with these vehicles, the 2000 and newer Buick LeSabre and Pontiac Bonneville use this pendulum-style head restraint system. Spring Activated The 2005 Mercedes-Benz M-Class features an optional spring-activated system for whiplash protection. If the sensing system detects a rear collision within a specific impact severity, it releases pre-tensioned springs inside the head restraints. This causes the head restraints to move immediately forward by about 40 mm and upwards by 30 mm. This movement is designed to support the heads of the front seat occupants at an early stage, lowering the possibility of a whiplash injury. After activation, the head restraints can be unlocked and returned to the original position using a tool supplied with the vehicle. Mercedes-Benz plans on making this option available on all models in the future. Pyrotechnic Head Restraint The pyrotechnic head restraint on the 2003 and newer BMW 7 Series is unique. On this system, a compressed gas cartridge at the base of the headrest frame (see Figure 5) activates during a rear collision, moving the headrest upward rather abruptly. The gas cartridge can be replaced, and the system reset if there is no further damage. Damage Analysis Repairs are usually limited to replacement on most of these whiplash protection systems, though some systems can be reset if there is no damage. Even though replacement is the usual repair, head restraints and these other systems discussed require attention after a rear collision. Check to make sure these parts are in proper working order. Since the seat belt and seat belt pre-tensioner are also an integral part of the seat and the restraint system, these should also be checked after a rear collision. Conclusion Efforts to reduce whiplash injuries from rear collisions appear to be a focus for vehicle makers for improving head restraints. Advanced regulations for vehicle makers are still being debated in the U.S. In the meantime, Europe has had a strict regulation in place for some time, which has led to many innovations in whiplash protection. Make it a routine practice to inspect head restraint parts as part of damage analysis. Also inspect the seat belts and seat belt pre-tensioners. More information on advancements in whiplash protection systems can be found in the I-CAR program "Advanced Restraint Systems (RES02)." Look for it in your area.
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