Saturday, May 11, 2013

EPO Oscars! Nominee - Prosthetic hand

Copyright © Françoise Herrmann
Artificial limbs evoke the horrors of amputation in wars, accidents and natural disasters… and as potential solutions, Captain Hook or the Bionic Man and Woman. The UPSTO awarded the first artificial limb patent for an artificial leg, -Patent No. 4834 - on November 4, 1846, to B.F. Palmer, himself an amputee. The artificial limb was made of hollow wood cones, articulated at the ankle and knee, with a corded pulley system, operating inside the steel knee joint. However, this was hardly the first artificial limb ever produced as there are stories told by the Greek historian Herodotus (in 484 BC) of Greek prisoners severing their limbs to escape, and then fashioning artificial feet, once healed (Brown 2000). And there are also countless archeological sites, dating from the Middle Ages and Renaissance, which have preserved ancient artificial limbs, fashioned of wood, leather, bronze or iron, for hands, legs and feet, even adjustable to fit a shrinking stump, and now exhibited in museums all over Europe (Brown 2000).

What is perhaps far less common and more recent, is the connection to children, and the focus on smaller hands. Indeed, this invention, nominated for a 2013 EPO award, precisely addresses the hurdles of designing high tech hand prostheses that are unconstrained by size, or the degree of amputation, in order to fit in all the electronic circuitry, and align the motors required to operate short enough digits for children, or just a few digits for partial amputees.

 European patent EP1962731, was awarded in 2008 to James David Gow, for PROSTHESES WITH MECHANICALLY OPERABLE DIGIT MEMBERS, precisely addressing the issue of miniaturized design for children. Using a worm gear inserted inside the digit to ensure transmission to a motor that is also part of the finger, the invention’s modular design also resolves the issue of partial amputations. The digits are each individually motorized. This digit technology then operates with skin sensors that pick up residual muscle movements, sent as signals to the hand digit motors, mediated by movement recognition and coordination software.

This patented prosthetic hand is produced by Touch Bionics, Ltd. as the i-limb, and it comes in many different configurations and sizes. Because of the modular design of the prosthesis that separates thumb and finger function, the functional range extends far beyond a single grip to include: 1. akey gripto pick up a small objet with thumb and index finger, to turn a key inside a lock or to adjust a camera focus lense; 2. apower gripfor holding a larger object such as tennis ball or holding an umbrella,; 3. anindex pointfor typing on a keyboard or other digital pad; and 4. athumb parkwhich folds in the thumb to assist with slipping through sleeves when putting on a shirt or sweater.

 In the absence of a hand for the most mundane tasks of pressing, turning, grabing, pulling, lifting and tying, in coordination with the other hand, and short of re-growing one, or bio-printing one (See  the Bioprint patent post on 2-08-2013, in this blog), this is state of  the art mechanical replacement technology, hailing from Scotland, in the UK. 


Brown, T. (2000) 
America’s first inventions: Popular patents from the airplane to the zipper.Lanham, MD: Scarecrow Press.


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