Leonardo da Vinci designed a screw jack, a lifting device that raises heavy loads through a threaded screw.
Leonardo’s notebooks contain studies of screw mechanisms used to multiply force. In a screw jack, turning a handle rotates a threaded shaft and moves a supporting platform upward. The mechanism trades speed for mechanical advantage, allowing a person to lift a load that would be difficult to raise directly.
Leonardo did not invent the screw principle itself. The ancient Greek mathematician Archimedes is traditionally associated with the water screw, and threaded lifting devices existed before Leonardo. His contribution was to study, refine, and apply mechanical systems systematically in designs for engineering and construction.
A screw jack should not be confused with Leonardo’s aerial screw, the separate rotating-aircraft concept often called a helicopter. The screw jack operates through contact between threads and is intended to lift objects from below. Leonardo’s mechanical drawings helped preserve and develop ideas that later became familiar in tools, vehicles, and industrial machinery.