Pictorials on pulleys first appeared in an Assyrian relief from the eighth century BC. This relief shows a very simple pulley, which can only change the direction of force, the main purpose is to facilitate the application of force, and will not give any mechanical interest. In China, the pulley device

pulley

pulley

The painting first appeared in the Han Dynasty portrait brick, Tao Jingmo. There is also an account of the pulleys in the Book of Mohism.

Ancient Greeks categorized pulleys as simple machines. As early as 400 BC, the ancient Greeks knew how to use the compound pulley. About 330 BC, Aristotle wrote his eighteenth question in the book "Mechanical Problems," devoted to "double pulley" systems. Archimedes contributed a great deal about simple mechanics Knowledge, explaining in detail the theory of kinematics of pulleys. It is said that Archimedes once used the compound pulley alone to pull a large ship full of cargo and passengers. In the first century AD, Alexander of Alexandria analyzed and wrote a theory about compound pulley, which proved that load and force Is equal to the number of rope segments that carry the load, the "pulley principle."

In 1608, in the book "Mathematical Collection", the Dutch physicist Simon Steffen showed that the ratio of the length of the path of travel between the force applied by the pulley system and the load is equal to the ratio between the force applied and the load Anti-ratio. This is the prototype of the principle of virtual work.

In 1788, the French physicist Joseph Lagrange unveiled the principle of virtual work using the principle of pulleys in the mega "Mécanique analytique" to unveil the mechanics of Lagrangian.