An escapement is a mechanical device found in clocks and watches that helps keep track of time. It converts the energy from a power source, such as a spring or weight, into distinct increments of ticks or beats that keep time. The escapement also serves to prevent the gears found within the escapement from turning too quickly, ensuring that timekeeping operates accurately and consistently. When they were first developed in the 13th century, they began replacing more rudimentary time-keeping devices such as sundials and water clocks. Dutch mathematician and astronomer Christian Huygens introduced the pendulum escapement in 1656 which provided clocks with substantially increased accuracy. The historical significance of escapements extends beyond the science of timekeeping by influencing the fields of engineering and physics through the principles of mechanics and the transfer of energy.

Various types of escapements have been developed over the centuries, each improving precision and reliability in horology. This is a model of an anchor recoil escapement developed by the English clockmaker William Clement in the early 1670s. His design was based on earlier pendulum escapement mechanisms, but he added the release and recoil feature. When the pendulum swings in one direction to the highest point in the arc, one of the components of the escapement, the pallet, releases the tooth of the escape wheel, which then moves the wheel forward. There is a slight recoil when the anchor shifts slightly backward after releasing the wheel. The model was a teaching aid made by William Samelius (1873-1961) who was a master clockmaker and Dean of American Watchmakers at the Elgin Watchmaker’s College in Elgin, Illinois which opened in 1920 and permanently closed in 1960.