Leonardo da Vinci designed a screw jack mechanism to lift and move heavy loads with screw power.
A screw jack converts rotational motion into controlled vertical movement. Turning the screw drives a load-bearing component upward or downward, allowing a relatively small force applied over many turns to move a heavy object. Leonardo’s mechanical studies included screw-based lifting arrangements for construction and engineering work.
The principle depends on the mechanical advantage of a screw. A fine thread can raise a load slowly and precisely, although it requires more turns. Friction can also help keep the load from falling when the handle is released.
Leonardo did not invent the screw principle itself; ancient and medieval engineers already used screws in presses and other machines. His importance lies in analyzing and adapting mechanisms systematically, including designs that resemble later lifting jacks.