Although ratchets are mentioned as one of automata mechanisms I"ve hardly seen one automaton made with this mechanism. Does anybody know an automata toy (paper or not) made with this mechanism? I would like to know, really.
I d'ont know ift that is exactly what you are looking for, but you should have a look at Walter Rufflers hompage:
You can build this and four more automata out of :
"A Handbook of Paper Automata Mechanisms" wtitten by Walter Ruffler
Should be available at amazon or any other (online-) bookstore.