Slouching Is In

Article From: 6/1/2007 Automotive Design & Production

 That’s right, the very posture your mother said was bad for you actually may be beneficial to the health of the human spine, and where better to introduce this technology than the place most people spend a bulk of their seated time in an uncompromising “proper” position?

 That’s right, the very posture your mother said was bad for you actually may be beneficial to the health of the human spine, and where better to introduce this technology than the place most people spend a bulk of their seated time in an uncompromising “proper” position? The change in focus, says Manfred Schlier, Grammer’s manager of Advanced Engineering, came out of new studies on the effect of different postures on spinal health. “Spinal discs are made of sponge-like material and have no blood flow. They retain and expel nutrients by switching between stressed and relaxed states,” he says. “Therefore, it is necessary for a seating system to allow and support movement that lets the spinal discs alternate between these states.” This flies in the face of past studies that suggest inter-disc pressure is much higher when sitting than standing, thus the best seating position is one that forces the back to imitate the forward-arching S-curve the spine assumes when standing. However, says Schlier, “The latest studies have shown there is no pressure difference in the discs when sitting or standing.”

Allowing the driver and passengers to change the arch of their backs while seated isn’t simply a case of adding a roller mechanism to a seat. That would spell disaster since acceleration, braking, and cornering forces would fling the occupants about uncontrollably. However, the mechanism by which the seat moves both the lower and seatback cushions in tandem also must have a fluid motion that lets passengers adjust the seat simply by shifting their weight. Thus, Grammer mounts the cushions to a platform isolated from the main seat structure, and places the center of gravity near the seat’s fulcrum. This lets passengers slouch or sit erect by applying a moderate downward or upward force at hip level, and locks the mechanism in place when that force is removed. The only downsides are that the relationship to the vehicle’s controls is altered as the seat moves from one position to another (especially the distance to the pedals), and the movement is reminiscent of that required by abdominal exercise equipment. “I don’t think most drivers will use the full travel of the seat for extended periods,” says Schlier, “and this change in the relationship would not affect passengers to the degree the driver might experience.” Though currently undergoing testing, Grammer says the “Ergomechanics” seat design can be ready for production in time for the 2010 model year. Instead of expanding its automotive seat business by supplying the seat directly to OEMs, it’s expected that Grammer will license the technology.


Grammer Automotive (Amberg, Germany; www.grammer.com) is a major supplier of rods and frames for automotive headrests (the VW Group and BMW each account for 40% of Grammer’s turnover, and the company supplies almost 80% of Mercedes’ headrests), though it also supplies seats for European trains and buses. While not a major seating supplier for automotive, Grammer’s portfolio also includes integrated child seats, arm rests, center consoles and other interior items.