Introduction Clock and watch escapments are the mechanical mechanisms which keep the pendulum or balance wheel moving. They are the most interesting part of these timekeepers. It is hard to understand how they work unless you see them in action. Fortunately, there are a number of Web pages featuring animations of escapments.
Most mechanical escapements give one or two pushes during each cycle.
Some electrical escapements, such as the Synchronome escapement, give pushes once every thirty cycles. Another escapement, the Hipp toggle, gives a push, perhaps every ten minutes, when the swing has gotten too small. The classic mathematical analysis of escapements and their errors was presented by English Astronomer Royal George Biddell Airy in 1826. On the Disturbances of Pendulums and Balances, and on the Theory of Escapements. is on the Web. This topic is extended in Rawlings' book.