3D prostetic Hand with flexible joints not screws or springs

thingiverse

I set up a motorized system for a young man named Sam, as he requested. To achieve this, I added a motor, making it functional. This design works well with strings too; I highly recommend using NinjaFlex material for joints and wrist attachments due to its ergonomic benefits. Aside from the flex joints, I learned that pairing two fingers allows them to work together effectively, maximizing their grip capabilities. Looping the string between one finger and the next enables continuous gripping even when one finger makes contact with an object. Picture this: grasping a ball with two fingers closing further than the middle pair due to the looped concept. This project leans heavily towards left or right hand dependence based on how it's assembled. However, I prefer the motor option as we are working with it now because there are numerous string pull setups out there; incorporate those concepts and add NinjaFlex material for joints. There is more to come... Check this video out to see the setup in action: https://www.youtube.com/watch?v=ypzqbA05EMY Instructions: 1. Print the Main Hand, motor mount, motor wheel, five sets of fingers, and five sets of knuckles. 2. You will need a few wrist attachments, but you may design your own based on user arm needs; some examples are provided. I used NinjaFlex material for the knuckles and wrist parts. 3. Mark finger joints to identify their pairing. 4. Notice finger order for easier disassembly. 5. I am finishing up a thumb that can rotate 40 degrees, changing its grip from a handshake position to grasping a bottle. This will be coming soon! The motor wheel has three holes where you'll insert eyelets after heating them up; attach the string and create a custom grip with paired fingers as discussed earlier. You will need: 1. Pololu Plastic Gear Motor: http://www.superdroidrobots.com/shop/item.aspx/pololu-200-to-1-plastic-gear-motor-90-degree-output/1306/1306 2. Limit Switches (CN0099): http://www.temcoindustrialpower.com/products/Limit_Switches/CN0099.html 3. 9-Volt Battery Wire Harness: http://www.lowes.com/pd_364309-37672-884476_0__?productId=3478193&Ntt=9v+battery+harness&pl=1&currentURL=%3FNtt%3D9v%2Bbattery%2Bharness 4. Rubber Fingertips for added grip: http://www.officedepot.com/a/products/964460/Swingline-Rubber-Fingertips-14-78-Diameter/?cm_mmc=PLA-_-Google-_-Mailing_Shipping_Envelopes-_-964460-VQ6-42102187796-VQ16c-VQ17-pla-VQ18-online-VQ19-964460-VQ20-73462265929-VQ21- I'm still experimenting with the Thumb Swivel feature, aiming to achieve a smooth swivel motion that can shift between handshake, ball-grabbing, and bottle-gripping positions. This should make gripping easier in various situations. For string use, I prefer 50 lbs test fishing line for its durability; each finger tip has a small recess where you can superglue the string when it reaches optimal tension. The rubber fingers cover this up for a clean finish. This is my glue of choice: Loctite Plastics Bonding System – http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm