Ralph Kalkbrenner says his first memorable childhood invention, fashioned from discarded wine barrel staves, old tires and paraffin wax, was purely utilitarian: He wanted skis, so he made them.

Today, the semiretired engineer from Irwin helps turn bright ideas into marketable products as a professional inventor.

Most recently, Mr. Kalkbrenner, 73, played a key role in developing the award-winning Hover Creeper concept. The prototype, which won a silver award in this year's Industrial Design Excellence Awards, IDEA, is essentially a backboard supported and made mobile by compressed air bladders. The product targets automobile mechanics frustrated with the unpredictable movements of the wheeled creepers typically used to slide under vehicles.

The 26th annual IDEA competition was co-sponsored by the Industrial Designers Society of America and BusinessWeek magazine.

Mr. Kalkbrenner, an employee of Davison Design and Development in O'Hara since last year, said he came up with the idea to use air as the creeper's driving force after observing air bearings being used to move extremely large loads, such as ship hulls and the undercarriages under trains.

"It occurred to me that it is not unreasonable to move a mechanic under a vehicle by a like means," he said, during an interview conducted by e-mail.

He put his idea down on paper and built a demonstration unit, which served as a starting point for the product's development.

The art of invention is nothing new for Mr. Kalkbrenner. In addition to the racing jalopies, walking stilts and wet paper wad guns of his days growing up in McKeesport, Mr. Kalkbrenner won 17 patents during his 31 years of employment with Westinghouse Electric Co. After retiring from Westinghouse, he worked from 2001 to 2003 for Maglev Inc. before retiring a second time.

"During my careers as an engineer, I had visions of someday being an inventor, since I always considered inventing a level above engineering," he said. "An engineer is asked to refine a product or process, whereas an inventor is given the opportunity to define a product or process."

That's why Mr. Kalkbrenner couldn't resist coming out of retirement a second time when he happened upon Davison's Web site advertising open inventor positions.

At Davison, he is part of a team that powers a 110,000-square-foot "invention factory." Despite the company's recent success in the design category, Davison has attracted a number of critics.

This year, a U.S. District judge ordered Davison and an associated company, Manufacturer's Support Services Inc., to pay $26 million in restitution based on Federal Trade Commission allegations that the businesses deceived would-be inventors by charging exorbitant fees for promised development and marketing services. The case, primarily against company President and CEO George M. Davison, was filed in 1997.

But for Mr. Kalkbrenner, the opportunity to invent at Davison has been a satisfying journey.

Although he has slowed his pace by working two days a week, he said, he is not ready to hang up his slide rule just yet.

"It's an enjoyable experience," he said.