A twenty-wheel pulley train and its windlass
Doubling loads from 100 to 102400 and the rope a winch takes up
A long row of paired pulleys (carrucole) is drawn across the foot of the sheet, its rope threaded from block to block and ending at a load marked 100. Number series that double from 100 up to 102400 run with the drawing, showing how each added wheel multiplies the force. The accompanying notes explain that a windlass (argano) must take up as many braccia of rope as there are wheels in the tackle for every braccio the weight is raised, and a short caption names the pole of a balance.
On this page
Pole of a balance
A brief caption labels the pole, or pivot, of a balance. It stands apart from the pulley study as a separate mechanical note.
System of pulley-blocks drawn across the sheet
The drawing is a train of pulley-blocks with a rope (corda arganica) running through the wheels, marked with points a and b and driven by a windlass. Multiplying the load by the number of wheels gives the force the system delivers. The figure occupies the lower half of the page.
Loads doubling from 100 to 102400
The number series running with the tackle doubles at each step, from 100 up to 102400, matching the successive wheels of the blocks. It sets out the geometric growth of the force between the markers a and b. The progression makes the multiplied load explicit alongside the drawing.
Rope consumed by the windlass
For a tackle of four wheels the windlass takes up four braccia of rope for every braccio the weight rises. In general the windlass requires as many more braccia of rope than the weight is lifted as there are wheels set in the blocks. The rule ties rope taken up directly to the number of pulleys.