Hand prosthesis with thumb adjustment mechanism

thingiverse

As part of my thesis research, I designed a mechanical hand prosthesis that utilizes 3D printing technology to change the thumb's position while bending the finger. This innovative modification aims to improve the grip maneuver in low-cost prostheses by enabling the setting of the thumb position. Using Autodesk Inventor Professional 2017, I developed the project based on the Cyborg Beast design from Thingiverse (https://www.thingiverse.com/thing:261462). The proposed concept for the hand prosthesis includes a ratchet mechanism that allows the thumb to change positions in five different variants. A critical component of this design is the aluminum tube, which serves as a mandrel with an axial opening. This tube passes through the main element of movement, ensuring smooth operation. A hole was drilled at the connection point between the pipe and the main element to route the thumb-pulling line to the bent position. To assemble the main movement element with the mandrel, I used cyano-acrylic glue to secure them together. Next, I led the line through prepared holes in the main movement element and the closer and further sticks, respectively. To facilitate assembly, I cut out two fragments from the mid-handle design, making it easier to integrate the main movement element with the mandrel. The hand prosthesis is designed to be efficient, reliable, and user-friendly, offering a significant improvement over existing low-cost prostheses. By enabling the setting of the thumb position, this innovative design enhances the grip maneuver, providing users with greater control and dexterity.