Dimples Steel Might Improve Gas Mileage, Reduce Global Warming

BOULDER, CO--(INTERNET WIRE)--Mar 25, 2002 -- Those dimples that were so hard to see in the last election may be useful after all. Boulder, Colorado inventor Paul Ericson describes three dimple-based inventions on his web site, www.bistabledome.org, and has patented their use in making digital shape sensors and flexible pumps. "They might help make cars lighter and stronger, improve gas mileage, and reduce global warming," he says, referring to his latest application.

Ericson makes dimples in strong metals that are thin enough so that on the other side of the dimple is a bump, or dome. When the metal around a dimple is bent far enough toward the dome side the dome snaps to the outside of the bend, leaving the dimple on the inside. He calls them flex-actuated bistable domes.

One way to improve fuel efficiency for SUVs without sacrificing strength is to use stronger steel that can be thinner and lighter. However, 'springback' has been a problem- the stronger steels have a tendency to spring back after stamping. "But closely packed dimples and domes with edges that meet in a honeycomb pattern turn metal with the bounce of a handsaw blade into a thin adjustable structure that stays where it's bent," Ericson says.

"When it's flat the dimples and domes alternate evenly but wherever it's bent they switch sides to adjust to the new shape and hold it. In profile it's a few times thicker than the original flat metal but it weighs the same," says Ericson. "The interlocking dimple/domes can also be used to add stiffness and control the way materials rebound or collapse during impact. Their characteristics and patterns can even be managed to force thin materials into simple shapes and perhaps save tooling costs. They might also be used to strengthen lightweight laminate materials."

For sensing shape the idea is to make them as small and numerous as possible and turn them into paper-thin contact switches in a low-cost flexible circuitry laminate.

"Used like a skin, rows of overlapping bistable dome switches can digitize the shape and motion of the surface parallel to them," Ericson explains. "The further you bend them the more they snap toward the outside. The digital pattern tells a computer where, how much, and in which direction it's bent. There's nothing on the market now with those 2D and 3D capabilities. At first it will probably be limited to low resolution applications but it's going to be cheap, and it's already digital," says Ericson.

"It could make almost any flexible surface into a shape sensor. That means clothing that knows how your body's moving and robots with a soft touch. It means security mats that know who's walking on them and car seats that know who's sitting on them. The car's computer will be able to recognize your butt print and control air bag deployment more safely. Many aspects of human-computer interaction can be improved. It opens possibilities for new applications of computer technology- for safety, ergonomics and rehabilitation, virtual reality, sports training, toys and games, robotics and automation," Ericson claims.

The web site also describes how the dimple/domes can be used to make flexible pumps. "It's a very simple pump with a one piece bistable dome pumping mechanism. No gears or motors. Any motion that bends the dimple/domes back and forth will do. They could be made very small and thin, maybe for medical applications. I'm working toward larger pumps that might use water waves for renewable energy generation or water desalination."

At present bistable domes are not being commercially produced. "I'm still looking for the right company or entrepreneur. So far dimples have been about as profitable for me as they were for Al Gore," says Ericson.

For more information and photos visit www.bistabledome.org.

bistabledome.org - P.O. Box 307, - Boulder, CO 80306, - USA