Leonardo da Vinci designed a screw jack for raising heavy loads.
A screw jack uses a threaded screw to convert rotational motion into lifting force. Leonardo’s notebooks contain mechanical studies of screw-based lifting devices, showing how a worker could raise a load gradually by turning a handle. The mechanical advantage comes from the screw’s long path around its axis compared with the small distance it advances during each turn.
Screw mechanisms were already known in antiquity and the Renaissance, so Leonardo did not originate the basic principle. His contribution was to analyze, adapt, and draw practical machine arrangements with unusual detail. His notebooks cover lifting, transmission, gearing, and construction equipment because these mechanisms were central to architecture, theater, and military engineering.
The screw jack should not be confused with a crane. A crane generally lifts through a boom, rope, and pulley system, while a screw jack raises a load directly through a threaded member. Modern vehicle jacks still use the same fundamental mechanical advantage, although many now use hydraulics instead.