David Rake: Week 8 - Prosthetic

Concept:

As an avid Mechanical bike rider I aimed for a bike related prosthetic. From the original drawing to the actual model slight tweaks were made in favor of a more realistic design. Instead of trying to curve the gears around a leg shape they were laid flat so actual gears could be put in place and be kinetic as well. Another addition is at the bottom where the foot would normally be I put a typical clip design for clip in shoes on road bikes.

Technique:

Starting with the gears they were modeled with curves and the teeth were polar arrayed around the center and slightly modified for imperfections. The top gear has 16 teeth and the bottom gear has 12 teeth. The indents in the gears were subtracted later using booleanDifference along with the holes going through them. In regards to the chains they are made with curves as well. They contain of 2 circles and a small curvy hourglass shape with a larger version of the same shape just outside of it.

These hourglass shapes were alternated along the pattern to create the full chain link. The smaller gear is directly in the center of the larger gear and so the chain tapers off towards the bottom instead of going straight up and down which I found difficult to work with. After trying (unsuccessfully) polar arrays to wrap the chains around the gears I resorted to manually rotating the chain around, which was not near as hard as I thought it'd be.

 The 2 gears and chain were then duplicated and positioned around the origin. The Bottom gear was rotated inward to almost create a seal in between the sets of gears. A cylinder was added in the center with other cylinders matching the angle of the gears to ensure a flat looking cap. the gears were booleanUnion(ed) to the cylinders and the bottom piece was added on with more simple boolean cylinder cutouts in the bottom for clip in pedals.

Materials:

I used a darker metal (Anodized Black) for the inner cylinder and gears. The chain used a lighter metal to highlight it (Chrome polished). These two materials are ironic due to their real world counterparts where the chain would more likely be dark due to oil and more abusive wear than the gears. This reverse setup looked much better in this situation however. The other material scheme caused the inner pieces to be difficult to see in depth.