Geared trip-hammer mechanism
Toothed wheels, a lever-held hammer and a twenty-bladed wheel
The upper sheet is crowded with mechanical studies for a hammer driven by toothed wheels, with a larger frame device and a fainter perspective sketch below. A note explains that the hammer, having passed beyond its perpendicular and about to fall, is held by the support n acting on the lever t, while the wheel s turns with force. Leonardo records the gearing: for every tooth the great left-hand wheel advances, the three-tooth wheel S moves one to the right; other drawings are marked with a count of twenty blades and the number 6 over a pinion. The companion sheet 67b verso, invisible before restoration, is without writings or drawings.
On this page
Hammer held past its perpendicular by a lever
The hammer has passed beyond its perpendicular and would fall were it not for the support n that bears on the lever t; then the wheel s moves with fury. For every tooth the great left-hand wheel advances, the three-tooth wheel S turns one tooth to the right. The parts are lettered n t p S.
Twenty-bladed wheel and pinion
The larger drawing is annotated with a count of twenty blades, and a pinion at the right carries the figure 6 — dimensioning notes for the toothed wheels driving the hammer train.