Leonardo da Vinci designed a screw jack to raise heavy loads by turning a threaded shaft.
A screw jack converts rotary motion into controlled linear lifting. In Leonardo’s drawings, a threaded screw works with a matching threaded component, allowing a relatively small turning force to lift or adjust a much heavier object. The principle depends on the mechanical advantage of the screw and the friction between its threads.
Leonardo did not invent the screw principle itself; ancient Greek engineers, including Archimedes, had already used screws in machines. His contribution was to study and apply mechanical arrangements systematically in Renaissance engineering sketches.
A screw jack is different from a hydraulic jack, which uses pressurized liquid, and from a lever, which pivots around a fulcrum. Leonardo’s design belongs to the long history of screw-based lifting devices that later became useful in workshops, vehicles, and construction.