Leonardo da Vinci designed a screw jack to move heavy loads vertically.
A screw jack uses a threaded screw to convert rotational motion into a slow, powerful lifting movement. Leonardo’s mechanical studies included screw-based lifting devices, reflecting his interest in machinery for construction, workshops, and military engineering.
The principle is based on mechanical advantage: a person applies force over a relatively long circular path at the handle, while the load rises a much shorter distance with each turn. This makes the device useful when a heavy object must be lifted precisely rather than moved rapidly.
Leonardo did not invent the screw principle itself. Ancient engineers, including Archimedes, had already used screws in machines such as water-raising devices. His importance lies in analyzing and combining established mechanical ideas into detailed Renaissance designs.