Johnson Controls is the only company to develop both kinds of market-accepted head restraint systems that protect against cervical spine syndrome in all segments
riACT head restraints efficiently protect against whiplash
Burscheid, Germany - August 4, 2010. Year after year across Europe, more than a million car drivers suffer from injuries to the cervical spine caused by low-speed, rear-end collisions. Known as cervical spine syndrome or whiplash, the injury not only results in personal pain and a lengthy recovery phase, but also immense costs. Experts estimate that the medical treatment of cervical spine syndrome resulting from traffic accidents adds up to ten billion Euros in Europe annually, and far more than 600 million Euros in Germany. Johnson Controls started early in developing head restraint systems that prevent injuries to the cervical spine or alleviate the consequences of a rear-end collision at this point in the body. The global manufacturer of automotive interiors and electronics is currently the only supplier offering the automotive industry both of the market-accepted active head restraint versions, either pro-active or re-active, which the company sells under the name "riACT."
Active riACT head restraints reduce the danger of whiplash
Independent studies show that appropriate protection systems can reduce the risk of long-term damage caused by whiplash by over 50 percent, while the danger of injury to the cervical spine is lessened by about a third. Intelligent head restraints, including riACT models from Johnson Controls, are effective instruments in preventing various cervical spine syndromes. They support the head effectively during a rear-end collision, preventing hyperextension of the cervical spine. "The protective effect is also maintained if the gap between the cushion and the back of the head has been set too large for reasons of comfort. This is because our riACT systems establish the proper distance within just fractions of a second in a worst-case scenario," Dr. Hasler outlines the advantages of the active head restraints developed by Johnson Controls.
The functional principle of the riACT head restraints is as follows: regardless of the selected initial head restraint position, the head restraint moves so close to the back of the head during a rear-end collision that the relative backward displacement of the head and the subsequent whiplash movement are prevented or strongly reduced. "We developed an intelligent telescopic mechanism based on a screw movement; this mechanism is located between the cushion and the back part of the head restraint. It connects these two parts, and in our pro-active design is biased by a spring. In our re-active model, the mechanism is activated by the passenger himself," Dr. Hasler explains the core element of Johnson Controls' riACT technology. As a comfort feature on the pro-active version, the cushion can be adjusted horizontally by up to 54 millimeters, so that each driver is able to individually set the most comfortable distance between the cushion and the back of the head.
If a rear impact occurs, the most important factor is to bring the cushion close to the back of the head as quickly as possible, bracing the head and preventing its backward displacement - an occurrence which is potentially hazardous. Dr. Hasler: "The head restraint thus needs a signal in order to be released. The difference between our re-active and pro-active riACT systems is how this signal is provided."
Re-active riACT system: body movement signals the crash
The re-active head restraint system receives the release signal from the occupant's body, serving as a sort of crash sensor. When the body is pressed into the lower section of the backrest during a rear collision, the surface pressure activates a mechanical actuator integrated within the backrest, which then tightens a Bowden cable. This leads through the backrest into the head restraint and propels the integrated telescope mechanism. "About 50 milliseconds after the impact begins, or 25 milliseconds after actuation, the head restraint cushion already reaches its final position - in any case, early enough to ensure that the riACT system achieves its full effect," says Dr. Hasler, referring to the results of internal test runs, which also confirm the Euro NCAP (European New Car Assessment Programme) crash test data. This independent organization evaluated the protective effect of the re-active riACT system in all tested vehicles, giving it a top grade of "good" - in one evaluation even with 3.7 points awarded out of 4, the highest score ever.
Pro-active riACT system: triggered by crash sensor
While the re-active system is actuated by the dynamic movement of the body in the event of an impact, the pro-active riACT head restraint utilizes the information of crash sensors to detect an accident. This information also controls the seat belt pretensioner and other restraint systems in the car. These sensors directly signal a small pyrotechnic unit in the head restraint once a predefined threshold value has been exceeded through acceleration. This unit is located in a release device, which under normal conditions blocks the biased telescopic mechanism. By igniting the small pyrotechnic charge, which is not harmful to health, a bolt is removed from its original position and the head restraint rapidly moves into its protective position. Since this happens independently from the movement of the body, Johnson Controls has named this riACT system pro-active. "By eliminating a range of mechanical components and providing faster information through the crash sensor, the pro-active head restraint moves to its final position within about 25 milliseconds after the crash signal," explains Dr. Hasler.
"Through its external activation, the pro-active head restraint has even more protection potential than the re-active model, especially when sitting position, weight or size of the person to be protected differs strongly from the norm. This higher protection potential also results in higher costs, which automotive vehicle manufacturers are more willing to accept for mid-class vehicles and those in higher segments," says Dr. Detlef Jürss, vice president engineering seating, interiors & systems Europe at Johnson Controls Automotive Experience. Dr. Jürss continues: "However, our goal is to use our riACT technology to make this increased safety attainable for purchasers of small and economically priced vehicles as well. This is why we have developed the re-active system for cars purchased in the millions in the more price-sensitive classes. Since small and compact automobiles have the highest registration rates almost everywhere in the world, this increased safety will benefit scores of motorists and also contribute to saving billions of Euros in the public health sector."
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