Box-wheel and clockwork studies, with a stone-thrower
Locking-and-releasing boxes (cassette) timed to run 'with the time of clocks'
The page develops the box-wheel: rollers (curro) and hinged boxes (cassette) that lock and unlock as the wheel turns, timed, Leonardo writes, "with the time of clocks." He specifies about a hundred boxes, each a finger wide and 1/8 braccio long, and describes how box b unlocks on meeting the lower roller while box a re-locks on reaching part of the wheel f, insisting that the releasing member m touch before the turning member n. Labels a, b, f, g, m, n mark the boxes, rollers and wheels; a separate note beside the figures gives "a way of throwing stones far."
On this page
Boxes that lock and unlock on the rollers
A detail shows two boxes and a roller labelled a b and f g, with about a hundred boxes each a finger wide and 1/8 braccio long. Box b unlocks as soon as it touches the lower roller, and box a re-locks when it reaches the part of the wheel f.
A wheel geared to the time of clocks
The wheel f g must be large enough to take the face of the box b that is to shift and the face of the box f that has shifted. Leonardo requires that it keep pace with the time of clocks.
Release before turning
Beside two rotating cylinders labelled n m the note orders that m, which unlocks, touch before n, which turns. The sequence of contact governs the escapement action.
A way of throwing stones far
A short caption beneath the clockwork figure announces a way of throwing stones far. It sits with a small sketch of a throwing mechanism.
The great box-wheel in three circles
The main figure is the great box-wheel with a detail of a single box: each box needs its pivots set on one of its faces. The boxes lie between three circles, each weighing one pound, and the lower roller receives a box of the second circle as one passes out of the first.