As someone who has always worked for somebody else, I'm in awe of people with the guts and talent to start and run their own businesses. And I'm doubly amazed at those who not only can manage a firm but drive its technology as well.

Take Bill Carls, founder of Numatics, which this year celebrates its 50^th anniversary. Carls, who immigrated to the Detroit area from Germany in 1924 at age 21, began his career as a toolmaker for a company that manufactured milk cans. By the time he retired in 1990 at age 87, he was a very wealthy man and a generous supporter of causes ranging from education to health care. Moreover, the company he founded has grown to include 15 plants in North America, as well as facilities in Europe, South America, and Asia.

And it all started, as so many industries do, with a design idea. Carls had a radical concept for an air valve, which in those days were common poppet designs with large rubber seals. His patented invention was a lapped spool-and-sleeve design, which eliminated the O-ring as a working part and instead substituted static seals on the sleeve. There was no metal-to-metal contact in this close-tolerance design. Rather, the spool floats on a cushion of air. It wasn't easy, but Carls convinced engineers in the auto industry to field test his valves on some of the toughest applications they could find. Bit by bit, he won them over with the valve's superior reliability and long life. Fifty years later, Numatics continues to improve Carls' original concept, but the fundamentals of his first design are still very much in evidence.

Like any successful engineer-entrepreneur, Carls did not rest on his laurels. He and his colleagues went on to pioneer many other innovations in fluid power, such as use of aluminum cast bodies, the 5-pin plug, direct solenoids, and integral speed control, just to name a few. And when it came time to move on, Carls sold the company to the people who had worked alongside him for many years. "He could have made a lot more money selling it to the highest bidder," says President John Welker, himself an engineer and a 30-year veteran of the company. "But it was more important to him that Numatics would be in the hands of people who shared his vision."

Numatics has become a formidable company in the fluid power field. So what could threaten it? Says Welker: "I'd say it would be someone in a two-car garage somewhere who has a radical idea--like Bill Carls did."

This special careers issue of Design News salutes all those engineer-entrepreneurs who had the grit to turn their "radical" ideas into reality.