Leonardo da Vinci designed a screw jack to raise or move heavy loads through mechanical advantage.
A screw jack converts rotation into controlled vertical movement. Turning the screw advances a threaded component, allowing a comparatively small force applied over a long distance to raise a much heavier object. Leonardo’s notebooks include studies of screws, gears, lifting devices, and mechanisms for construction and military engineering.
The importance of the design is not that Leonardo invented every principle involved. Screws and lifting devices had ancient precedents, but Leonardo analyzed them systematically and proposed practical mechanical arrangements. His drawings show how he connected geometry with the behavior of machines.
A screw jack differs from a pulley system. A pulley changes the direction or mechanical advantage of a rope, while a screw jack uses the inclined-plane principle wrapped around a cylinder. Modern vehicle jacks still use related screw-based mechanics, although many contemporary jacks are hydraulic instead.