Big Rope winch (Colla Grande)
From Leonardo da Vinci, Codex Atlanticus, f. 1083v.
Use
Lifting large loads in the worksites of the dome of The Cathedral of Florence.
Motor
Animal-driven shaft power.
Description
This winch makes it possible to lift loads in three different speeds, thanks to the different diameters of the spools on which the ropes are wrapped. The carousel is moved by a couple of draft animals and is mounted on a shaft with two gear wheels which can be geared alternatively thanks to the screw mechanism, making it possible to reverse the wheel without changing the direction of the animals.
Interpretative Issues
Dimensions: based on the “animal carousel” we can estimate that the base of this machine was at least 4 meters wide by 7-8 meters long and 6-7 meters tall.
Reconstruction: the way the pawl of the ratchet wheel is designed makes it move only in rotating direction. In Leonardo’s foglio there are also other construction drawings of the gear teeth but it is impossible to establish with certainty if they are details of the machine.
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