You guys who are machinists and tool-and-die-makers must have had a good laugh when you saw my crude mock-ups!
(At least I hope so.
I took some machine shop in vocational school 40 years ago, and I often wish I had pursued that field.
Looking at their web site, firms like Rush Gears are what made America great. A can-do attitude with the skills to back it up.
I expect Le Chat Noir can and will fabricate a nice tranny, chain gang or otherwise, for The Contraption. Myself, I would like to track down suitable junk and off-the-shelf parts to assemble a number of chain gangs for my Kinetic Kontraptions -- cheaply. How many? I could install nine of them right now, and more in the future. Two ratios would be a good thing, but three or four would be much better. In Kinetics, we need as much as a 20:1 range of gear ratios, so some intermediate ratios are kind'a needed.
Some years ago I found a source of industrial gear boxes that could probably do the job. But they are built to order and cost thousands.
I have a setup on a single-seater that gives me a 12.25:1 range, and it was plenty at the Ventura race. But Ventura is an easy course.
Hmmm.... I'm just Train-Of-Thought Brainstorming here. (Sunday morning and frost on the ground.) And a lightning bolt just struck....
It's about that 12.25:1 setup I just mentioned. That thing is at least $650 worth of parts, and it cannot take much torque, but it is a stepless transmission. Yep, a Continuously Variable Transmission. It's actually two trannies in series -- one unit has a 3.5:1 range. Itâ€™s a bicycle wheel hub called NuVinci. Take a look at this, if you wish: http://www.fallbrooktech.com/
Looking at the animation, it is not difficult to understand how the ratios are changed. Pretty clever. It took me longer to understand how the force is actually transmitted, but I believe it boils down to friction. There must be a bit of preload on the balls, and then the â€œsecret recipeâ€