I'm guessing a counter. Counts to 1000. You have 3 gears, each with 10 teeth, and one vertical pin on each gear intended to engage the teeth of the next. Each gear has a spring that engages the spaces between the teeth in order for each wheel to remain locked in it's last position unless manually advanced by the lower gear. (i.e. they are not freewheeling.)

I would also hazard a guess that the metal flange/tab in the left was used as a interface/guide for the actuating mechanism, which would interface with the first/lowest gear, and the big spring on top probably served as a return spring for the actuating mechanism.

And now, having demonstrated a level of nerdiness beyond even my wildest dreams, I shall now proceed to take a lethal dose of Paracetemol. It's been a pleasure...