Beltboxes

One of my favorite genres of systems to design are gearboxes. This is one of the first things I practiced doing back when I was a wee laddie in the summer of 2018. I really wasn’t particularly skilled back then, and so my main attempt to make my designs stand out was to make them unusual. The FRC season had just ended, and I had encountered timing belts for the first time. I was instantly enchanted: You can transmit power over long distances without using tensioners? Amazing.

So, the natural response was to start designing everything with belts (which I still haven’t really stopped doing). What if I made a gearbox, but with belts? I even had a clever little idea for an idler to have a bit more wrap on the motor pinion pulleys. Never had the world seen such innovation.

…It didn’t quite turn out how I wanted (also, I accidentally made the drive reduction double what it should have been). I abandoned the notion as a failure. There were always more clever ideas to have, and this one didn’t seem to have been that clever. I really did like the idler though, which had a set of bearings on the same shaft as the wheels.

About a year passed, and as I scrolled through my pictures I saw the beltbox with new eyes. That design was even worse than I thought it was. However, the concept was pretty reasonable. I went back at it with more humility and sleep, and came up with a result I actually liked. This was actually a pretty cool idea. It ended up with a final gear reduction of 6:1, which provides a very reasonable 14-15 ft/s free speed off 3.5″ wheels. I really enjoyed re-imagining this design that I had done much earlier in my obsession with CAD, and it gave a nice sense of closure.