Leonardo da Vinci designed a screw jack to lift heavy loads by turning a threaded shaft.
A screw jack converts rotational motion into lifting force. Turning the handle advances a threaded screw through a fixed or moving nut, raising a load gradually. The mechanical advantage comes from the screw’s small pitch: a long turning distance produces a shorter, powerful vertical movement.
Leonardo drew screw-based lifting mechanisms among his studies of machines and construction equipment. Such designs could help raise heavy materials or adjust components with precision. They built on older knowledge of screws, wedges, and lifting devices rather than appearing from nowhere.
A screw jack is different from Archimedes’ screw, which is primarily a water-raising device. It is also different from a pulley crane, which lifts through ropes and wheels. Modern vehicle jacks often use a similar screw principle, although many now use hydraulic pressure instead.