Composite pulling

In his studies of mechanics, Leonardo analyzed the operating principles and advantages offered by pulleys for the purpose of transmitting motion, and especially for lifting heavy loads.

This model represents a block and tackle composed of 33 pulleys, 17 of which are fixed on the upper supporting structure while the remaining 16 are fixed on a mobile wooden beam in the form of a parallelepiped. The beam is suspended by means of the rope passing through all the pulleys, which is fitted, at one of its ends, with a small counterweight. This small counterweight is enough to keep the weight of the parallelepiped in suspension, because its load is distributed over the 33 pulleys.

Leonardo declares that, among devices for lifting weights, this one is quite sure, and the most suitable for regulating and prolonging the descent of the weight in a clock.