The Leonardo da Vinci machine intended to lift heavy loads using a combination of gears and a screw was a screw jack.
Leonardo studied mechanical lifting devices that converted rotary motion into a slow, powerful upward movement. In a screw jack, turning a handle or gear rotates a threaded screw; the screw’s mechanical advantage allows a relatively small input force to raise a much heavier load.
The principle was already known before Leonardo, but his notebooks contain detailed studies of gears, threaded mechanisms, and lifting machinery. Such devices could have applications in construction, military engineering, and workshop operations. Their strength comes from the screw’s low-speed, high-force motion and the friction that can help keep a raised load from falling immediately.
A screw jack is not the same as a crane or a simple pulley. A crane is a broader lifting machine, while a pulley changes force direction or provides mechanical advantage through rope and wheel arrangements.