Mark Stark, an inventor and independent design professional in the electrical/electronic manufacturing industry, is a Popular Science 2011 Inventions of the Year award winner for an electronics-free articulating hand that he designed and developed. Stark’s invention is on the June cover of Popular Science.
Dubbed the Stark Hand, the prosthesis is a minimalist plastic design that is light and moves like an electronic hand. According to the description in Popular Science, each of the hand’s fingers has three knuckles that bend separately to conform to anything the wearer grasps, including irregularly shaped objects. The thumb has two knuckles. Hooks attach to a socket at the end of an amputee’s arm and are operated by a pull cable that runs up to a shoulder harness. The Stark Hand screws into the same socket-and-cable system as a body-powered hook 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, which allows all five fingers to 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 glass’ bowl. Coil springs in each of the 14 joints exert pressure that is gentle enough to hold a light bulb but strong enough for the wearer to lift a chair.
Stark made his first prototype in 2004 for one of his friends, Dave Vogt, who was born without a left hand. The prototype was fabricated from hardware-store supplies.
Within an hour of donning the prosthesis, Vogt caught a ball left-handed for the first time in his life. Since then, he has helped Stark test and improve four more prototypes. Vogt now wears the hand everywhere except to work since his machinist’s job requires heavy lifting, a task that is best suited for his hook.
A more durable production version, which will use tougher plastics and sleeker parts, could be on the way as early as this winter. Edison Nation, Charlotte, North Carolina, an idea-to-shelf product developer, recently selected Stark’s hand for commercial development and is now in talks to license it to a major prosthetics manufacturer.
Stark’s hand was also featured in the January issue of Inventors Digest.