Escapement

An escapement releases a clock’s gear train in controlled increments, allowing the timekeeping regulator to govern the wheels’ motion and producing discrete ticks.

Balance wheel: A wheel that oscillates back and forth to regulate the rate of a mechanical clock or watch. In a portable clock, its oscillations unlock the escapement at regular intervals.
Oscillation: Repeated motion that varies around an equilibrium or repeats through a cycle. A clock regulator’s recurring oscillation sets the rhythm of escapement releases.
Anchor escapement: An escapement using an anchor-shaped lever to engage a toothed escape wheel. It became the standard escapement for pendulum clocks, replacing earlier designs.
Salisbury Cathedral clock: A large iron-framed clock in Salisbury Cathedral, traditionally dated to around 1386. Its surviving mechanism includes an early verge-and-foliot escapement.
Pendulum: A suspended body that swings under gravity, with a period determined largely by its length. In pendulum clocks, each swing cues the escapement to release a tooth.
Torque: The turning effect of a force, equal to force multiplied by its lever arm. The clock’s driving torque presses escape-wheel teeth against the locking surfaces.
Deadbeat escapement: A recoil-free escapement whose escape wheel rests against a stationary locking face. Its lack of recoil improves pendulum-clock timekeeping compared with recoil designs.
Verge escapement: An early escapement using a vertical spindle with pallets that alternately catch an escape wheel. It was used in early mechanical clocks before the anchor escapement enabled longer pendulums.
Gear train: A sequence of meshing gears that transmits and transforms rotational motion and torque. The escapement meters the gear train’s otherwise continuous drive from the power source.
Friction: The resistance to relative motion between surfaces in contact. Friction at the escapement’s contacts consumes energy and can alter its rate.

Linked from 14 pages