Leonardo da Vinci sketched a screw jack as a machine for raising heavy loads.
A screw jack converts rotary motion into controlled vertical movement. Turning the screw advances a threaded component and lifts the load gradually, giving the operator mechanical advantage and precise height control. Leonardo’s engineering studies explored this principle for construction and other heavy work.
The screw jack belongs to a long history of lifting devices; screw-based mechanisms existed before Leonardo. His contribution was to analyze and depict mechanisms systematically, often combining screws with frames, handles, and supporting structures.
It is also distinct from the aerial screw. The aerial screw was a proposed flight machine using a rotating helical surface to generate lift, whereas a screw jack is a ground-based lifting device that uses a threaded screw to raise a load.