Crank-driven shaft raising weights by pulleys
The ratio of the winding ropes r S and a b governs how much weight d moves relative to c
A round shaft is turned by a crank at the right; ropes wound on it pass over two pulleys at the left (S and b) and raise two hanging weights, c and d. Leonardo states that the motion of weight d relative to c follows the proportion between rope r S and rope a b — equivalently, the more the right angle a exceeds the acute angle n, the more d moves than c. The sheet applies his proportional analysis of motion to a practical winding-and-pulley lifting device.
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Winding shaft with crank and twin pulleys
A round shaft, cranked at one end, carries ropes that wind upon it and run over two pulleys (S and b) to raise two weights, c and d. The device is a compact winch in which the winding radii of the two ropes differ.
Rope ratio and angle governing the weights' motion
Whatever proportion the length of rope r S bears to rope a b, the same proportion holds between the motion of weight d and that of weight c. Equivalently, the more the right angle a exceeds the acute angle n, the greater the motion of d compared with c.