Twin Tipping Cases for a Hoisting Machine
Detachable material boxes that empty by turning over, mounted by hook and ring; a balance and crane sketched
The sheet works out an instrument fitted with two detachable cases so that, while one empties, the other fills to save time; each case is four braccia long and its base opens lengthwise in two parts. Leonardo prefers a version (the mode a b c) that pivots near its balance point at f so that little force tips it over, and that hooks on and off by a ring n dropped over a hook (rampino) m, light enough for a single man. Sketches show a hoisting arm, a beam balance carrying two weights, and the tipping boxes with their hooks, rings and pivots.
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Twin cases that empty and fill in turn
Leonardo specifies that the cases of the instruments be detached from the cord, so that as one goes to empty the other fills bit by bit to save time. Each instrument therefore gets two cases, each four braccia long, one and a half wide and one and a third high, with a base that opens lengthwise in two parts when it rests.
The pivoting mode a b c, hooked by ring n over hook m
The mode a b c is judged the best, because standing at f almost at the pivot its load is nearly balanced, so little force is needed to tip it. It can be attached and detached easily by the ring n on the hook m, and a single man suffices to work it; the case is one and a third braccia high, four long and one and a third wide.
Hoisting arm and beam balance
A tall hoisting arm or crane is drawn faintly across the top of the sheet, and a beam balance carrying two weights spans the center. Below them the tipping cases are shown with their hooks, rings and a pivot fitting, illustrating how the boxes hang and overturn.