Leonardo da Vinci designed a screw jack, a lifting device that uses threaded mechanical motion to raise heavy loads.
A screw jack converts rotation into slow, controlled linear movement. When a threaded screw turns inside a matching part, the load rises or falls by a small distance for each revolution. This provides mechanical advantage: a relatively modest force applied over a long turning motion can move a much heavier object through a shorter distance.
Leonardo studied screw mechanisms in many forms, including lifting devices and machines for construction. His drawings show how he approached practical engineering through geometry, mechanical advantage, and careful arrangement of parts. The screw jack should not be confused with a crane, which commonly uses ropes, pulleys, or booms to lift loads.
Screw jacks became important in presses, workshops, vehicles, and building equipment. Leonardo did not invent the screw principle itself, which was ancient, but his notebooks contain sophisticated Renaissance applications of it. The design illustrates how he adapted established mechanisms to solve demanding engineering problems.