Fusion Arm

Prosthetic hand design, designed as part of an arm for trans-radial amputees Upper arm parts are still to come.

Maker/DIY

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Description

Prosthetic arm designed for trans-radial amputees. Upper arm parts are still to come. Parts are very small, I recommend printing them at at least 180% maybe 240% for an adult. The finger joints can be printed on their sides, just make sure they are printed with the connecting male/female parts facing up in order to avoid needing any support structure.

Finger 1 (*5) - first finger joint

Finger 2 (*4) - second finger joint

Finger 3 (*4) - third finger joint

Thumb 1 (*1) - first thumb joint

Thumb 2 (1*) - Second thumb joint

Thread an elastic string (~6") Through the top of in each finger and down through the palm, tie it off tightly at both ends.

Thread a strong and thin non-elastic string (~18") through the bottom set of holes. Tie it off at the finger tip (I usually tie it around the  base of the elastic knot at the finger tip)

Gorilla Glue (or some kind of strong glue like Rez n Bond) nub into upper arm and arm cup p1 to arm cup p2

Try to keep the tension as similar as possible and tie all the the strings around around nub with a little bit of tension (just enough that the fingers are very slightly bent)

When you pull the plain strings (bend elbow) coming out of the base of the palm, the hand should close.

--- UPDATE: I've stopped threading regular string through the thumb (but still use elastic), it works better rigid ---

--- Fairing can replace arm cup p1 ---

*number needed for full hand

Please note, This arm is not extensively tested

Materials and methods

PLA and ABS should both work

Documents

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Comments

86f88511f9cfd20d927837ec2d13b666?default=blank&size=40neo777 added this to the Prosthetic Arm Project collection ago
Eb7a0e60922c213fd772948b023a30ec?default=blank&size=40krx added this to the MAKE collection ago
7a47094062ad53f21b149025d0282484?default=blank&size=40Gustavo Abel Cierra added this to the Protesis collection ago
522a863b565c40259cc81416f4a20efe?default=blank&size=40Thomas Bauer added this to the Arms collection ago
Mini rowanRowan Zajkowski added this to the Awesome! collection ago
Mini img 20180413 114555Felicity published this design ago