@hawkthrower @hawkthrower I've worked on reproductions of a few medieval clocks and its always some time of clutch mechanism. If you watch this video closely at 1:30 when the maker is winding the clock you can both see and hear the clutch. Look to the upper right of the video and you will see it click. It allows the wheel to freely rotate in one direction (while winding) but not the other when the clock is running. At 2:42, the camera zooms in on the clutch.

At 2:30 you zoom in on a very modern looking gear. What is the purpose of this gear?