Leonardo da Vinci sketched a screw jack to lift heavy loads using a screw mechanism.
A screw jack converts rotational motion into a slower, powerful upward movement. Turning the screw moves a load-bearing component along the threads, allowing a relatively small input force to raise a heavy object. Leonardo studied screw mechanisms as part of his broader work on machines, force, and mechanical advantage.
The screw jack belongs to a long history of lifting devices that includes ancient screw mechanisms and later mechanical jacks. Leonardo’s contribution was not the invention of the screw principle itself, but the detailed analysis and application of mechanical systems in Renaissance engineering drawings.
A screw jack differs from the hydraulic pump designs also found in Leonardo’s notebooks. A hydraulic device uses pressurized fluid, while a screw jack relies on threaded mechanical contact. The design is therefore a mechanical lifting machine, not a hydraulic one.