Leonardo da Vinci designed a screw jack, a lifting machine based on a threaded screw and gears.
A screw jack converts rotary motion into slow, powerful upward movement. In Leonardo’s design studies, gearing was used to turn the screw and raise a load with mechanical advantage. The arrangement reflects a practical Renaissance interest in moving heavy materials more safely and with less direct force.
A screw jack is different from a pulley block, which lifts through rope tension and sheaves. It is also different from a hydraulic jack, which uses pressurized fluid. Leonardo’s drawings show the mechanical principle, but surviving evidence does not establish that he manufactured a standardized jack for widespread use.
The idea belongs to a larger family of machines Leonardo examined, including hoists, cranes, winches, and gear trains. These studies demonstrate his habit of adapting simple mechanical elements into compound machines.