Leonardo da Vinci designed a screw jack, a lifting machine that raised a platform through a rotating screw.
The mechanism used a threaded screw to convert rotary motion into controlled vertical movement. Turning the screw moved a load-bearing platform upward or downward, giving the operator mechanical advantage. Leonardo’s notebooks contain studies of screw mechanisms and lifting devices for engineering and construction work.
A screw jack is different from the self-propelled cart often associated with Leonardo. The cart was a vehicle concept, while a screw jack was a stationary lifting device. It is also different from a crane, which generally lifts loads through a boom, rope, and pulley arrangement.
Leonardo’s drawings show his interest in making heavy loads easier to raise with compact mechanisms. Screw-based lifting devices have a much older history, so Leonardo should not be credited with inventing the screw jack itself. His contribution was the detailed study and application of mechanical principles in Renaissance engineering designs.