The Stark Hands
Prosthetic hands typically come in three varieties: purely cosmetic models; hooks and other low-cost mechanical appendages that provide a limited range of motion; and electronic versions that better mimic natural hand movements yet can cost tens of thousands of dollars. Mark Stark’s prosthetic incorporates the best elements of each. Although its minimalist plastic assembly is nearly as light and inexpensive as a common steel hook, it looks and moves like a high-end electronic hand.
Stark, who makes his living designing valves for dryers and other appliances, got into prosthetics in part to help his friend, Dave Vogt, who was born without a left hand. Stark’s creation is electronics-free, but its fingers each have three knuckles (two on the thumb) that bend separately to conform to anything the wearer grasps, including irregularly shaped objects that a hook can’t hold.
The Stark Hand screws into the same socket-and-cable system but adds a lever on the palm that connects to five more cables, each running up the back of a finger. A shoulder movement triggers the lever to tug all five fingers open at once, and the individual cables let each finger rebound on its own. Springs in each joint contract until each finger comes to rest on an object, so some fingertips can curl around, say, a wineglass stem while others grasp the cup.