The attachment part of the harness is now complete, leaving only the addition of the forearm piece to be added.The arm was too wide by a factor of two– something easily fixed by changing around a few values in the sketches that make up the arm. CAD and 3D printing are truly amazing for rapid prototyping. The full assembly should be ready by early next week; then, the foam has to be added to the inside of the socket using a laser cut wooden template to get its shape just right.
This week we assembled the full gripper thumb hand. The mechanism is quite simple, as the main focus is the grip and hold onto objects. An elastic band holds the thumb to the hand and keeps it in the closed position. The hand can be opened by either using the other hand or by pressing the thumb against the object. Once the object is in the hand the elastic creates a tight grip, and once the object is removed the elastic returns the hand to a closed position. Grips will be added to the fingers to provide a better hold. A video demonstrating this is included below.
A new version of the harness was created this week. This harness has straps that cross in the back and are adjustable from the front. On the left side, there is an elastic band that will secure around the bicep, with adjustable straps hanging down to connect to the socket.
Later this week, we will be testing out our 3D structure scanner to prepare for taking virtual measurements of Chris’s residual limb. Additionally, we will experiment with making a plaster mold using quick-drying plaster gauze. The goal is to come back from the first trip with both virtual and physical models, so that we can make the necessary adjustments before returning.