Leonardo da Vinci studied screw jacks that used a vertical screw to raise heavy objects.
A screw jack converts rotary motion into a slow, powerful upward movement. Turning a handle rotates the threaded screw, and the threads push a load-bearing platform upward. Leonardo’s mechanical drawings explored this principle for lifting and positioning heavy materials with controlled force.
The screw jack was not Leonardo’s sole invention. Screw-based lifting devices were known before the Renaissance, but his notebooks contain careful studies of screws, threads, and mechanisms for applying them. His work shows how he analyzed practical machines by separating them into repeatable mechanical actions.
A screw jack differs from a winch, which usually winds a rope or cable around a drum. It also differs from a simple lever because the screw provides continuous mechanical advantage and can hold a load in position when the operator stops turning.