What kind of mechanical device did Leonardo da Vinci design to keep a wheel turning at a steady rate?

Leonardo da Vinci designed an escapement mechanism to regulate a wheel's movement at a steady rate.

An escapement controls the release of energy in a mechanical system, allowing a gear or wheel to advance in measured steps. Leonardo's clock studies included a verge-style escapement with components that alternately locked and released a toothed wheel.

Leonardo did not invent the mechanical clock, and his escapement drawings did not immediately replace established clock mechanisms. They are important because they show his detailed interest in timekeeping, friction, gears, and controlled motion. The word escapement applies to a broad family of mechanisms, so the specific design should not be confused with the later anchor escapement used in many clocks.