What Leonardo da Vinci device was a rotating bridge designed for rapid military deployment?

Leonardo da Vinci designed a revolving bridge intended for rapid military deployment.

The bridge was planned to rotate around a central support so that it could be swung into position across a gap and then moved away when necessary. Leonardo’s design included structural members and counterbalancing ideas intended to make the bridge manageable for an engineering crew.

A quickly deployed bridge could help an army cross a river or ditch without constructing a permanent crossing. It could also be removed to deny an enemy the same route. Leonardo’s military notebooks repeatedly connect engineering design with battlefield mobility and fortification.

This device differs from a drawbridge, which normally pivots upward from one end to open a fixed crossing. Leonardo’s revolving design was intended to turn horizontally around a support, making its movement and tactical use different.