Leonardo da Vinci designed a screw jack using a rotating threaded shaft to lift heavy loads.
A screw jack converts rotary motion into controlled linear motion. When the screw turns, its threads move a nut or platform upward or downward. This gives the operator mechanical advantage and allows a load to be positioned gradually and accurately.
Leonardo studied lifting machines extensively, including hoists, cranes, winches, and threaded mechanisms. His drawings show how a screw could be combined with a frame and handle to raise substantial weights. Such devices were useful in construction, engineering, and workshop settings.
Leonardo did not invent the screw principle itself. Ancient Greek engineers had used screws, and screw-based lifting devices existed before the Renaissance. His contribution was the detailed analysis and inventive combination of established mechanical ideas. A screw jack is therefore a more precise description than calling the design a crane.