Mechanical Fingers Give Strength, Speed to Amputees

July 2, 2007 — -- If the X-Finger looks like a prop from The Terminator, relax. It isn't out to kill you, and it isn't robotic. In fact, it's a mechanical prosthetic finger so effective it provides articulation as fast and flexible as the real thing.

Invented by Dan Didrick of Naples, Florida, the device has no batteries, electronics, servos or actuators. Instead, each digit incorporates a simple mechanism which, when pushed by the surviving part of the wearer's finger, curls a set of artificial phalanges.

"Having a body-powered device leaves little room for mechanical failure," Didrick said, adding that there aren't any robotic medical alternatives. "Many people assumed a device such as mine already existed."

In practice, however, robotic fingers are always attached to robotic hands and arms. Losing an entire limb, however unpleasant, allows the prosthetic manufacturer more room to conceal complicated electronics.

About one in 150 people have lost a digit to war, misadventure or misfortune.

Made of steel and blue plastic, Didrick's X-Finger allows for a surprising degree of dexterity: Enough to grip (and swing) a golf club, operate a keyboard or even play musical instruments.

In May, Didrick was awarded second prize in the History Channel's Modern Marvels Invent Now Challenge, beating thousands of other entries to claim a $5,000 award.

The X-Finger, which currently costs thousands of dollars per digit, might seem expensive to prospective buyers. But it's not a get-rich-quick scheme for its inventor: Didrick, 37, sold his house, his Porsche and many of his personal possessions to help fund development, and he draws only a modest salary from sales of his invention.

"We only receive a fraction of the overall costs ourselves," Didrick said. "Also, many people would be surprised to learn that a cosmetic silicone artificial finger, offering only passive function, with no mechanical structure, can cost $5,500 from an anaplastologist."

Didrick's X-Finger works much like a real finger, with its flexing motion actuated by movements in the surviving parts of the wearer's finger and hand.Manufacturing is currently taken care of by a firm in California, but it is able to make only a few fingers a week. Investment will expedite production, Didrick hopes.