Talon Ratchet Hand

Description

This is a ratcheting version of Peter Binkley’s Talon hand. A ratchet mechanism keeps the prosthetic hand bent and the fingers closed without the wearer having to keep tension in their wrist muscles. This would be handy for any activity that requires the fingers to be closed and grasping for more than a few seconds, like riding a bike, carrying a pail, etc. Here is a video showing how it works: https://youtu.be/4vWE3Bn5seU I saw a version of a ratcheting hand on a non-enable website, but the design seemed too flimsy and complex, so I decided to make something simple and sturdy for the e-NABLE Talon, Osprey, and Ody hands (which all use the same bracer and boxy palm style). A different design would be needed for the Phoenix, Raptor, and Cyborg hands because of the location of the bracer straps on those designs. The ratchet modifications use everything in the standard Talon hand except for the bracer. The additional parts are the pawl, lever, wheel, and longer wrist pin. All the files are at the standard Talon 100% scale. The bracer and lever have right and left handed versions. The wheel, pawl, and wrist pin work for either right or left. For hardware you will need: Number 4 pan head self-tapping screws: (2) 3/4” for attaching the lever and pawl to the bracer, (2) 1/2” to attach the wheel to the palm, and (1) 1/4” to attach the spring to the pawl. (4) small plastic washers for the top and bottom of the lever and the pawl A small spring. We didn’t have one short enough so we took a longer one and cut it in half and bent down the last two coils. Everything you need should be at your local hardware store. For the prototype, the parts were all made from PLA. For a hand going to a recipient, I would make the wheel out of something stronger like nylon, or print out a couple extra PLA wheels for the recipient.

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