This seems to be an appropriate place to (re)post this. Not sure about the practicality of this mechanism in an FRC environment and I have yet to test at speed or for torque. This project was my own and done on my home printer, I am working to introduce more things like this to my team as we’re soon acquiring a Markforged printer.
My closest to a finished project, the one I have the best grasp on is a 50:1 cyclo speed reducer that I was able to simulate (new to me) , 3D print, and assemble. I have yet to test it under load but I am working on plans to set that up.
Lesson learned on this one, I had to measure the OD and ID of the pin pattern, resize and reprint the main “gears”.
I’m also introducing bearing races into my design work. This is the outer race of an angular contact bearing set (one on each hub) with the principles of a gothic/2 point contact geometry built-in.
I’m also using this project to introduce heat-set inserts into my printable designs. This hub features the ‘standard’ 1.875" bolt pattern found on most FRC COTS hubs. I made the mistake of freehanding the first one and let the inserts cause protrusions on the OD that I then had to sand back down. The second hub I wrapped in Kapton tape (high heat polyamide?) and the inserts went in “flawlessly”.
The other patent that piqued my interest was for an internally self-recirculating, ball driven, double enveloping (globoid) worm. I only have the model of the worm and the wheel (gear) on this one and I am currently running into walls for how to print this without supports. I’ll likely split it into two halves and use pins and a chemical weld for PETG (if they make one?) to put the two halves together. I’m not sure how applicable it would ever be to FRC use but I thought it to be cool as hell and something I could scale to FRC size regardless. It uses two technologies that I am familiar with at work as well which is always a nice connection (we use ‘Cone-Drive’ products in a few of our machine axes and we have/had a patent on the Internal Return Ball Nut).
Four-point contact on a gothic arch profile
Internal return, self-circulating path
1/2" hex for scale
That is all for now, I likely won’t advance much further with either project at this point in the summer. I usually feel the need to scratch that mechanical itch in short bursts and I think I’m all out for now. Perhaps I go back and finish one of the other 100 projects I started in the last few years. Maybe something with an artistic flourish, like finishing and painting this.