Leonardo da Vinci’s chain-drive design used linked elements and toothed wheels to transmit rotary motion.
Leonardo’s notebooks contain studies of chains, sprockets, and mechanical transmission. In a chain drive, a rotating sprocket pulls a chain, which turns another sprocket at a distance. This arrangement lets motion and power pass between shafts without requiring them to touch directly.
Leonardo did not invent the modern bicycle chain or the complete industrial chain-drive systems used today. His drawings instead show an early understanding of how linked parts could transfer movement reliably. The idea belonged to a wider body of work on gears, hoists, pumps, and machines for manufacturing.
The design is sometimes confused with Leonardo’s self-propelled cart, but the two are different. The cart was a complete vehicle mechanism, while the chain drive is a transmission principle that can be used inside many kinds of machines.