Ankerhemmung

Ankerhemmung, or anchor escapement, is a type of mechanical escapement used in pendulum clocks to regulate the release of the gear train and to provide impulses to the pendulum. It consists of an anchor-shaped lever with two pallets that interact with the teeth of the escape wheel. The escape wheel is driven by the clock’s gear train, and as the pendulum swings, the pallets alternately engage and release the teeth, converting the wheel’s continuous rotation into the back-and-forth motion of the pendulum while delivering periodic impulses.

Operation is based on alternating engagement and locking: during each half-oscillation, a tooth of the escape wheel pushes a pallet, freeing the wheel to advance by a small amount and imparting a forward impulse to the pendulum. The anchor then locks the wheel for the remainder of the swing, preventing recoil and limiting energy loss. The impulse is typically delivered near the end of the pendulum’s swing, which helps maintain a stable rate with a relatively long pendulum.

History and usage: The anchor escapement was developed in the late 17th century and became standard in many longcase and wall clocks in the 18th and 19th centuries. It marked an important improvement over the older verge escapement by reducing recoil and energy loss, enabling longer, more accurate pendulums. While still recognized in horology as a fundamental design, many modern timepieces now employ alternative escapements, such as the lever escapement, especially in watches.

Variants and maintenance: Variants of the design vary in geometry and pallet shape. Typical constructions use steel pallets and bearings, sometimes with jewel bearings to reduce wear. Proper alignment and lubrication are important for consistent ticking and accuracy; wear, misadjustment, or damaged pallets can cause irregular operation.