Leonardo da Vinci designed a screw jack to lift heavy loads using a threaded mechanism.
A screw jack converts rotational motion into slow, powerful vertical movement. Turning the screw moves a load-bearing part upward or downward, allowing a relatively small force to control a much heavier object. Leonardo’s design applied this principle to lifting and construction work.
The machine reflects his interest in mechanical advantage: devices can trade speed for force. A screw jack is slower than simply raising an object by hand, but its threaded arrangement can multiply force and hold a load in position.
Leonardo’s screw-based lifting designs were part of a long history of mechanical engineering rather than an entirely new principle. His contribution was to analyze and draw practical arrangements with unusual clarity and technical detail.