Cuckoo Clocks

The design of a Cuckoo Clocks are now conventional. Most are made in the "traditional style" (also known as "carved") or "chalet" to hang on a wall. In the "traditional style" the wooden case is decorated with carved leaves and animals. They have an automaton of the bird that appears through a small trap door while the clock is striking. The bird is often made to move as the clock strikes, typically by means of an arm that lifts the back of the carving.
There are two kinds of movements: one-day (30-hour) and eight-day clockworks. Some have musical devices, and play a tune on a Swiss music box after striking the hours and half-hours. Usually the melody sounds only at full hours in eight-day clocks and both at full and half hours in the one-day timepieces. Musical cuckoo clocks frequently have other automata which move when the music box plays. Today's cuckoo clocks are almost always weight driven, though a very few are spring driven. The weights are made of cast iron in a pine cone shape and the "cuc-koo" sound is created by two tiny gedackt (pipes) in the clock, with bellows attached to their tops. The clock's movement activates the bellows to send a puff of air into each pipe alternately when the timekeeper strikes.