What are the 3 weights used for on the cuckoo clock?

Answer 1

One weight functions the cuckoo sound and other features (such as woodchoppers, beer drinkers, chimney sweeper [on chalet-style clocks only]), one functions the ticking and one functions the music box and dancers and water wheel [on chalet-style clocks only].

Answer 2

The three weights on a cuckoo clock control different functions: the left weight powers the timekeeping, the center weight powers the cuckoo sound and any music features, and the right weight powers the clock's pendulum. Keep all three weights wound to ensure the clock functions properly.