They are powered by a weight pulling the chain downward. The links in the chain catch in the teeth of the gear and that gear moves another which moves the clock hands. They are wound once a day by pulling down on the chain.
All but one of the clocks are accurate to about a minute per day.
My dad's clocks are easy to reset, but I still haven't changed the time on all of the clocks in my home yet, so it's as if we have different time zones from room to room, depending on how difficult the clock is to reset. I should probably get on that now. Sorry I couldn't collage these for you, but the collage monkey and I weren't getting along today.
I hope you liked seeing the clocks.