Leonardo da Vinci designed cam mechanisms to produce continuous motion in some machines.
A cam is a shaped rotating component that converts rotation into a controlled reciprocating or oscillating movement in another part. Leonardo used cam profiles in studies of mechanical devices, including machines that required repeated lifting, pressing, or striking actions.
Cams were not invented by Leonardo; ancient and medieval engineers had already used related mechanisms. Leonardo’s contribution was his extensive analysis and drawing of machines, which helped document how shaped surfaces could coordinate motion and transmit force.
The term is often confused with a crank or a gear. A crank changes rotary motion into reciprocating motion through an offset connection, while a cam uses its profile to guide a follower. Leonardo’s notebooks contain combinations of cams, gears, screws, and linkages, so a drawing may show several mechanisms working together rather than one isolated part.