England · c. 1715 (predates the modern English patent-specification system in general use)
Deadbeat (Graham) Escapement
Historical attributionThe standard escapement of precision regulator clocks for two centuries, and still used in fine reproduction and astronomical regulators.
The deadbeat escapement removes the recoil of the earlier anchor escapement: as the pendulum overswings, the escape-wheel teeth rest dead against a flat locking face rather than pushing the wheel backward, which greatly improves regularity in precision pendulum clocks.
Graham did not patent the mechanism and reportedly shared it freely, which is one reason it spread quickly through English precision clockmaking of the eighteenth century.
Background
The deadbeat escapement was invented around 1675 by astronomer Richard Towneley to address the recoil issues found in the earlier anchor escapement. While often credited to George Graham, the mechanism was first utilized by Thomas Tompion in clocks commissioned for Sir Jonas Moore and the Greenwich Observatory. The mechanism functions by utilizing pallets with two distinct surfaces: a curved locking face and a slanted impulse face.
As the pendulum approaches the bottom of its swing, the tooth shifts to the impulse face, providing the necessary push to maintain motion. This design successfully removes the backward recoil force present in earlier escapements, thereby reducing friction and improving isochronism.
Written from the encyclopedia entries listed under Sources; each statement was checked against the cited text.
How it works
- The escapement uses escape wheel teeth that are radial or slanted forward to ensure consistent contact with the dead faces of the pallets.
- The dead face is a curved surface designed to be concentric with the anchor's axis of rotation.
Later history
- Initially reserved for precision regulators due to strict manufacturing tolerances, the escapement became common in quality pendulum clocks throughout the nineteenth century.
- Most modern pendulum clocks now employ this escapement design.
How to verify this yourself
No patent to search: verify attribution and mechanism description against clock-history literature (e.g. the Antiquarian Horological Society's published research) rather than assuming a filed specification exists.
Manufacturers known to have used it
- English regulator-clock makers, 18th–19th century
- later precision clockmakers worldwide
Photographs
Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.
Sources & references
- Anchor escapement, Wikipedia (English), retrieved 2026-10-28 (text CC BY-SA 4.0)
- Antiquarian Horological Society, published research on George Graham
- Britten, F. J., Old Clocks and Watches and Their Makers
Where sources disagree, the disagreement is stated rather than resolved silently.