Leonardo da Vinci designed a screw jack to test and apply the lifting power of screws.
A screw jack converts rotational movement into a slower, powerful vertical lift. Turning the screw advances a threaded component, allowing the device to raise a heavy load with much less force than lifting it directly. Leonardo’s notebooks contain studies of screws, gears, and mechanical advantage that helped him explore this principle.
The same basic idea appears in many later machines, including vehicle jacks, presses, and adjustable supports. Its usefulness comes from trading speed for force: a long series of turns can produce a substantial lifting effect.
Leonardo did not invent the screw itself. Ancient Greek engineers had already used screw mechanisms, and devices such as the Archimedes screw served different purposes, especially moving water. Leonardo’s significance here is his detailed Renaissance analysis of how threaded mechanisms could be used in lifting and machinery.