Leonardo da Vinci designed mechanical clock mechanisms using weights, gears, and regulating parts.
His notebooks contain studies of clocks, gear trains, escapements, and related mechanisms. These drawings show him analyzing how stored energy from a falling weight could be transmitted through gears and controlled so that the hands moved at a steady rate.
Leonardo did not invent the mechanical clock. Weight-driven mechanical clocks had appeared in Europe by the late Middle Ages, and earlier timekeeping devices included sundials, water clocks, and hourglasses. His importance lies in the detailed mechanical investigations recorded in his notebooks, not in creating the first clock of any kind.
The word “pendulum” requires care in this context. Galileo later studied the regular motion of pendulums, and Christiaan Huygens patented the first successful pendulum clock in 1656. Leonardo’s clock studies predated that development and should not be described as a working pendulum clock. They are evidence of his sustained interest in precision mechanisms and controlled motion.