Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4066583.

My mother needed a cup holder to attach to her wheel chair so she could holder her coffee mug while taking the dogs out. Or just cruising around the house.

This is what I came up with, to attach to her armrest tubing, but could probably work in a number of places. I opted to go with a zip tie approach since we were prototyping, but it has some real strong benefits. Since the bottom rests on a bracket, and even though the zip ties are tight, it swivels easily on the round tube. Plus it seems like it would fit easily in a number of different spots using this method making it easier to install on different makes of chairs.

The cup holder has a 92mm Inner Diameter at the top, and about 70mm at the base. Fits most of the to-go coffee mugs (without a handle) that we had here at the house.

EDIT: Updated the files. I left my mom's name on the files. LOL unless you are named Carol, you probably don't need these with that name on them.