What is "anchor escapement"

Anchor escapement \An"chor es*cape"ment\ (Horol.)

1. The common recoil escapement.

2. A variety of the lever escapement with a wide impulse pin.

In horology, the anchor escapement is a type of escapement used in pendulum clocks. The escapement is a mechanism in a mechanical clock that maintains the swing of the pendulum by giving it a small push each swing, and allows the clock's wheels to advance a fixed amount with each swing, moving the clock's hands forward. The anchor escapement was so named because one of its principal parts is shaped vaguely like a ship's anchor.

The anchor escapement was probably invented by British scientist Robert Hooke around 1657, although some references credit clockmaker William Clement, who popularized the anchor in his invention of the longcase or grandfather clock around 1680. When Clement's clock appeared Hooke claimed the invention of the escapement, saying that he had shown a clock with the same escapement to the Royal Society soon after the great fire of 1666. The earliest known anchor clock is Wadham College Clock, a tower clock built at Wadham College, Oxford, in 1670, probably by clockmaker Joseph Knibb. The anchor became the standard escapement used in almost all pendulum clocks.

A variation without recoil called the deadbeat escapement was invented by Richard Towneley around 1675 and introduced by British clockmaker George Graham around 1715. This gradually superseded the recoil escapement and is used in virtually all modern pendulum clocks with anchor escapements.