The excavating machine: wheel and boom
A large spoked wheel drives a long tapering jib ending in a hook
A single sketch shows the excavating machine in side view: a large spoked wheel set in a boxed frame at the left drives a long tapering boom that reaches to the right and ends in a hook or pulley marked a, with a small circle o beside the frame. The note lists its principal dimensions, giving the wheel as four braccia wide and ten and three-quarter braccia high, the axle three once thick, and the boom nineteen braccia long. It records the working proportions of the earth-moving rig developed on the surrounding pages.
On this page
Dimensions of the wheel-and-boom machine
The note specifies the machine: the wheel four braccia wide and ten and three-quarter braccia high, the axle (polo) three once thick, and the boom (falcone) nineteen braccia long. These figures fix the size of the great driving wheel and its long lifting jib.
Hoisting jib for clearing a trench
The long tapering boom reaching to the right ends in a hook or pulley at the point marked a, the arm by which spoil would be raised out of an excavation. The wheel in its frame at left provides the power to work it.