Weight-driven geared machine with a clock-like escapement
A 2000-pound weight drives a train of toothed wheels regulated like a clock verge
On blue paper, Leonardo lays out a tall weight-driven mechanism: a large toothed wheel of the first motion meshes with an upper lantern pinion and further wheels, while a long rod descends to a heavy weight at the foot. The notes specify the gearing (a wheel of 2 braccia with 50 teeth, a pinion of 10 spindles, wheels of 40 and 30 teeth, a bar of 30 braccia) and a load of 2000 pounds. A lever a b keeps a hanging, swinging stone in motion, and a counterweight rides in a notched wheel exactly like the verge of a clock so that it never loses time. A small house-like frame and a pendulum device are drawn at the left.
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Gear train: wheel of first motion, lantern pinion and driven wheels
The wheel of the first motion is to be 2 braccia across with 50 teeth. Above it a lantern pinion of 10 spindles carries a wheel of 40 teeth and another of 30. A bar 30 braccia long descends to a weight of 2000 pounds at its foot.
Lever a b sustaining a swinging stone
A lever labelled a and b is provided to maintain the motion of the attached stone as it swings. It keeps the hanging weight oscillating rather than coming to rest.
Counterweight acting as a clock verge
A counterweight works above with its rod set in a notched wheel, in the manner of the verge (aste del tempo) of clocks, moving now at the top and now at the foot. In this way it never loses time.