Since returning from Haiti, we have been working on the individual pieces of the device to make specific modifications. Once these are finalized, we will reassemble the device and prepare for the next trip!

Put a sock (in) it

The laser scan was imported into the CAD software to allow for a virtual fitting. With this, the original socket was edited in order to better fit the arm. Some adjustments still have to be made to the socket, as the fit was tight in a few places when the foam was added to the interior wall. All in all, things are coming along well, and a finalized socket should be done within the week. Ensuring the forearm will be angled naturally will be the harder portion of the design.

Need a hand?

For the most part, the hand did not need any adjustments. One thing that we did want to change, however, was the shape of the thumb. The first thumb design was mostly straight and would tend to slip on larger curved objects, such as water bottles. To fix this problem we decided to rotate and curve the thumb so that it will wrap around objects more. We also plan to add grip to the inside of the thumb to further prevent slipping.

Sew it goes

The overall design of the harness succeeded in transferring the weight of the device from Chris’s arm to his back and shoulders. The main change we want to make is to connect the socket by straps with buckles, so that Chris can put the harness and socket on separately. This way it will give him the flexibility of wearing the harness underneath his shirt if he wants. Another slight variation to this version involves adjusting the angle at which the straps cross in the back. Shoutout to Iris for being our model!

The new version has been sewn together, and the next step will be finalizing the design for the detachable connection to the socket. Below are some of the options.

Casting call

Last week we used the plaster cast, made from wrapping plaster gauze around Chris’s residual limb, to make a replica of his arm. A mixture of Plaster of Paris and water was poured into the mold and allowed to dry; then the gauze cast was cut away to unveil the final result. While the surface is still rough from the texture of the gauze, the shape is consistent with the 3D scan of the arm, which we scaled and printed out. We can now use both models to test the fit of the socket.

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