What rotating machine did Leonardo da Vinci design to raise heavy loads?

Leonardo da Vinci designed a screw jack as a rotating machine for raising heavy loads.

A screw jack converts turning motion into a slower, powerful lifting motion. Leonardo’s drawings show how a threaded screw and associated gearing could raise or lower a platform. The mechanical advantage comes from the screw’s small advance for each rotation, allowing a relatively modest force to move a much heavier object.

Leonardo did not invent the screw principle itself; screw mechanisms were known in the ancient world. His contribution was to study and develop practical machine arrangements using screws, gears, and frames. A screw jack is different from a simple pulley, which changes the direction of force or provides mechanical advantage through rope and wheels. The same general principle remains in some modern mechanical jacks.