Leonardo da Vinci designed a screw jack, a lifting device that uses a threaded screw to raise a heavy load. His mechanical studies explored how rotational movement could be converted into controlled vertical motion.
Turning the screw advances a platform or nut along the thread. Because the screw provides mechanical advantage, a relatively small force applied over a longer distance can lift a much heavier object through a shorter distance. This made the principle useful for construction, positioning, and other engineering tasks.
Leonardo’s drawings belong to a long history of screw-based lifting devices rather than representing the first use of every underlying idea. His importance lies in analyzing and illustrating mechanisms systematically. A screw jack differs from a crane, which usually lifts with a boom, rope, or chain; the defining feature here is the threaded screw that carries the load.