Talon Ratchet Hand

thingiverse

This is a ratcheting version of Peter Binkley's Talon hand that incorporates a reliable mechanism to keep the prosthetic hand bent and fingers closed without requiring constant tension in the wearer's wrist muscles. This design would be especially useful for activities demanding finger closure and grasping for extended periods, such as riding a bike or carrying a heavy bucket. A video demonstrating its functionality can be found at https://youtu.be/4vWE3Bn5seU. I had previously encountered a ratcheting hand design on an inaccessible website, but the concept seemed overly complex and fragile, prompting me to create a simpler and more durable version tailored for the e-NABLE Talon, Osprey, and Ody hands (which share the same bracer and palm style). A different design would be necessary for the Phoenix, Raptor, and Cyborg hands due to their unique bracer strap placement. The ratchet modifications utilize all standard Talon hand components except for the bracer. Additional parts include the pawl, lever, wheel, and longer wrist pin. All files are provided at 100% scale of the standard Talon hand. The bracer and lever have right and left-handed versions, while the wheel, pawl, and wrist pin work for either right or left. For hardware, you will need: (2) Number 4 pan head self-tapping screws, 3/4" long to attach the lever and pawl to the bracer (2) Number 4 pan head self-tapping screws, 1/2" long to attach the wheel to the palm (1) Number 4 pan head self-tapping screw, 1/4" long 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 used a longer one and cut it in half, then bent down the last two coils due to unavailability. All necessary components can be found at your local hardware store. For the prototype, all parts were printed from PLA. However, for a hand intended for a recipient, I would recommend making the wheel from a stronger material like nylon or printing additional PLA wheels as a precautionary measure.