In the process of developing a 3D printed prosthesis for transhumeral amputations, we arrived at a solution for the elbow joint, and after some iterations, we decided to share it to get some feedback from the community.
This elbow module is designed to be fitted to a 3D printed socket (to be designed specifically for each user) and be fastened with screws ( Illustrated in the pictures). The mechanism is basically a gear with a ratchet that locks thanks to a spring. The hand is meant to be positioned manually, and to be operated with opposite shoulder movement by the harness ( still in development). The operating principles is explained in the video.
Along with the printable files, we share the public fusion 360 link, where you can find all the parts, understand how we designed them, and modify them as you wish. Please do share your improvements with us and all the community! Take into acount that the hand and fingers where not designed using Fusion 360, but by editing Gyrobot's Flexyhand and Cathy's Lucky Fin by Rhadamanthys76. (See ArmPO v3)
FUSION 360 PUBLIC LINK: https://a360.co/2GKau47
For any questions, comments or personalization requests don't hesitate to contact us at firstname.lastname@example.org
This is a project that was developed along the "Universidad Católica de Asunción" as a final thesis project for Industrial Design.
All the parts where printed using a Flashforge Guider II, and they may vary a bit using other printers or settings.
1_elbow: 50 % infill, 0.2 layer height, Speed: 80 mm/s
2_swoosh: 80 % infill, 0.2 layer height, Speed: 80 mm/s
3_cover: 80 % infill, 0.2 layer height, Speed: 80 mm/s
4_whipple+lock: 50 % infill, 0.2 layer height, Speed: 80 mm/s
5_flexible: 30% infill, 0.2 layer height, Speed: 15 mm/s
6_hand: 20 % infill, 0.2 layer height, Speed: 80 mm/s
7_fingers1: 20 % infill, 0.2 layer height, Speed: 80 mm/s
8_fingers2: 20 % infill, 0.2 layer height, Speed: 80 mm/s
In addition to the printed parts you will need:
- 6 screws (2.5mm diameter, 12mm long)
- 2 iron rods: (120mm and 124mm)
- 1 spring: comp 9x30mm
- multifilament fishing line