Leonardo da Vinci designed a screw jack to lift heavy loads on building sites.
A screw jack converts rotational motion into slow, powerful vertical movement. Turning a threaded screw advances a nut or platform, allowing a relatively small force applied over many turns to raise a heavy object. Leonardo studied and drew mechanisms based on this principle as part of his wider work on machines and construction equipment.
The screw jack was useful because it offered controlled lifting rather than the sudden movement associated with some simpler systems. It could be applied to heavy materials, structural components, or machinery that needed precise adjustment. Leonardo’s mechanical studies often focused on how gears, screws, pulleys, and levers could be combined.
Leonardo did not invent the screw principle itself; screw-based lifting devices existed before his lifetime. His contribution was to analyze and develop mechanisms systematically, recording their geometry and possible uses. A screw jack is different from a crane, which generally lifts by means of a boom, rope, and hoisting mechanism.