What mechanical device did Leonardo da Vinci design to improve the accuracy of clocks?

Leonardo da Vinci designed an escapement mechanism to improve the accuracy of clocks.

An escapement controls the release of energy from a clock’s driving weight or spring. It allows the gear train to advance in measured steps rather than turning freely, while producing a regular oscillating or reciprocating motion. Leonardo drew clock mechanisms that explored this controlled release of power.

His studies belong to a long history of clock engineering rather than representing the modern escapement in its final form. The pendulum clock, which greatly improved precision, was developed later by Christiaan Huygens in the seventeenth century.

Leonardo’s clock drawings show how carefully he examined gears, regulating parts, and motion. They are often described broadly as clock inventions, but the most precise answer for the regulating component is “escapement mechanism,” not pendulum clock.