Leonardo da Vinci sketched a screw jack, a lifting mechanism based on a threaded shaft.
A screw jack converts rotational motion into controlled vertical movement. Turning the screw moves a load-bearing part along the threads, allowing heavy objects to be raised with relatively little force. Leonardo studied this principle in connection with mechanical engineering, construction, and machines for lifting or moving loads.
The screw jack belongs to a much older family of devices. The Greek mathematician Archimedes is traditionally associated with the development of the screw, and threaded lifting mechanisms existed before Leonardo. His contribution was to analyze and depict mechanisms with unusual clarity in his notebooks.
Leonardo’s drawings should therefore not be treated as proof that he invented every machine he sketched. He was an inventive designer and a careful observer who often improved, combined, or explained existing technologies. The screw jack remains a useful example of how his notes connected geometry, force, and practical engineering.