What Leonardo da Vinci invention used a four-wheeled cart powered by coiled springs?

Leonardo da Vinci’s self-propelled cart used coiled springs to drive a four-wheeled vehicle without an external animal or person pulling it.

Leonardo designed the cart in the late fifteenth century, probably around 1478–1480. Two large, wound leaf springs supplied stored energy. When released, the springs turned the wheels through a system of gears. The front wheels could be set to follow a predetermined path, giving the cart a limited form of programmable movement.

The machine was not an automobile in the modern sense. It had no internal-combustion engine, battery, steering wheel, brakes, or practical method for carrying passengers over roads. Its short, controlled motion was more suited to theatrical displays, court entertainments, or demonstrations of mechanical ingenuity.

A full-scale replica was built for a 2006 exhibition at the Museo Galileo in Florence. The cart is also frequently described as an early robot because its programmed path allowed it to move automatically. That label is modern, but it captures the design’s unusual combination of stored energy and predetermined motion.