Leonardo da Vinci designed a screw jack to lift heavy loads through the mechanical advantage of a threaded screw.
A screw jack converts rotational motion into slow, powerful linear motion. Turning the screw advances a threaded component, allowing a comparatively small input force to raise or support a much heavier load. Leonardo's mechanical studies included screw-based lifting devices for construction and workshop use, where controlled movement was more valuable than speed.
The idea was not unique to Leonardo: screw mechanisms were known in antiquity and had many uses before the Renaissance. His contribution was to analyze and draw practical arrangements of familiar mechanical principles. A screw jack differs from a windlass, which winds a rope around a drum, and from a block and tackle, which uses pulleys. Modern vehicle jacks preserve the same basic principle, though they use stronger materials and standardized threads.