This is a fun little project I did on a camshaft spring mechanism. It shows a back and forth movement, were it goes forth quit slow and then goes back really fast, when the rotational speed of the handle stays the same. The back going movement takes about ¼ of the forth going movement.
I also challenged myself to only use 3D printed parts. So there are no fasteners needed.
This mechanism might be useful if one wanted to make something that requires a pick and place movement. For the moment it’s actually just a desk toy.