Leonardo da Vinci designed a screw jack, a lifting machine that uses a threaded screw to raise heavy materials with mechanical advantage.
A screw jack converts rotational motion into slow, powerful vertical movement. Turning the screw advances a threaded component, allowing a relatively small applied force to lift or hold a much heavier load. Leonardo’s notebooks contain studies of screw-based lifting devices and related mechanisms.
Such machines were useful in construction and workshop settings, where controlled lifting mattered more than speed. The design belongs to a long history of screw mechanisms, which had ancient precedents and were also used in presses and other machines.
Leonardo’s contribution was his systematic examination of geometry, force, friction, and practical construction. A screw jack is not the same as a crane: a crane generally uses a boom, rope, and hoisting system, while the jack raises a load directly through a screw.