Grammer Implements Ergomechanics Seat Design

TROY, Mich. - Grammer AG Automotive, a leading supplier of automotive interior systems and components, has thrown away conventional automotive-seat design and introduced a new design philosophy it refers to as Grammer Ergomechanics.

Conventional seat mechanics force the spinal column into a double-S shape even when the occupant changes the angle of the backrest. By contrast, Grammer Ergomechanics permits natural body movements, allowing the occupants' spinal column to change shape, while still providing proper support.

Grammer's Ergomechanics design philosophy has been developed and installed for the driver, front-passenger and backseat passenger seats on a unique Volkswagen Passat prototype.

"Grammer's new seats operate automatically," said Manfred Schlierf, manager of Advanced Engineering at Grammer. "In other words, there is no need for the occupant to pull or push a lever. The user simply changes their sitting position and the seat automatically adjusts itself."

Background: Looking at the Needs of the Human Spine While Sitting

"Human bodies are made for standing, running, climbing and so on," Schlierf said. "However, nowadays people spend most of their time sitting at work, at their desks, in their cars and during their leisure time. Therefore, proper seat design is critical from both a comfort and a health perspective."

Classic thinking is that it is better for humans to stand than sit. But, if people must sit, then their backs should imitate the standing position and the spine should assume a natural double-S shape, according to Schlierf.

A 1966 report by Professor Alf Nachemson, a distinguished orthopedic surgeon and researcher from Sweden, revealed that the pressures inside spinal disks are greater when people are sitting than when standing. However, new research recently reported by Professor Dr. Hans-Joachim Wilke at the University of Ulm's (Germany) Institute of Orthopedic Research and Biomechanics showed that spinal pressure is actually the same or less when a person sits.

Furthermore, human spinal disks do not contain blood vessels, but instead are nourished by a process of alternating hydration and dehydration.

"Like a sponge, when in a relaxed, stress-free state, a person's spinal disks soak up fresh nutrients, which is the hydration process," Schlierf said. "When stressed, they squeeze out used nutrient fluid, which is dehydration. It is vital for seat designs to allow for movements that both apply and relieve stress to allow the human spinal column to function properly."

After Wilke's study was released, Grammer designers realized that automotive seats shouldn't force occupants' back to imitate a standing position.

"It's best for the back to switch frequently between lordosis - a position where the lumbar spine is arched forward - and kyphosis, which is a relaxed position," Schlierf said. "The natural movement between these two postures nourishes the spinal disks."

Grammer's new design helps the spine move naturally by changing the shape of the backrest to alternatively induce lordosis and kyphosis postures. Ergomechanics doesn't force the spine into a double-S shape caused by conventional seat mechanisms. Instead, it permits natural movement - while providing support in every position.

"In contrast to static sitting, our ergomechanics design allows the occupant to readily change his or her sitting position to exercise different sets of muscles while letting others relax and recover," Schlierf said. "Ergomechanics moves all joints including the feet, knees, hips, shoulders and elbows as well as the spinal vertebrae. This prevents tension in the back, shoulders, neck and head."

With Grammer Ergomechanics, the driver remains at the same distance from the pedals and steering wheel, and keeps the same angle of vision.

About Grammer

Headquartered in Amberg, Germany, Grammer AG is a specialist in the development and production of components and systems for automobile interiors, as well as driver and passenger seats for offroad vehicles, trucks, buses and trains. Grammer's key division, Automotive, supplies headrests, armrests and center consoles, as well as integrated children's seats to well-known automakers and vehicle systems suppliers.

The company's second division, Seating Systems, includes two business units - Driver Seats and Passenger Seats. Driver Seats is an OEM and aftermarket supplier for prominent truck and offroad automakers. Passenger Seats supplies original equipment manufacturers as well as bus and train operators.

Grammer is represented in 17 countries worldwide with more than 8,700 employees in 21 subsidiaries. The company's shares are listed in the S-DAX segment of the German Stock Exchange and are traded on the Munich and Frankfurt stock exchanges, the Xetra electronic trading platform and the OTC markets of the Stuttgart, Berlin and Hamburg stock exchanges.

In fiscal 2006, Grammer Group sales were $1.21 billion. Additional information is available at www.grammer.com.