A spring lock released by a key, and coupled lever motion
Levers n, m and g lift the catch f; a note that if a goes to c, b goes to n
Folio 50r is dominated by a lock-like mechanism set in a rectangular plate, surrounded by keys, springs and jointed levers. The text describes how, when the key moves lever n toward b, n lowers a second lever m; as m falls, g also lowers and raises the catch f, unlocking its nose, after which the springs return the joints to their first positions. A small separate figure notes that if a moves toward c, b moves toward n. Labels include f, spring [molla], pole [polo], m, g, n b and key [chiave].
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Key-worked train of levers that lifts the catch f
Turning the key drives lever n toward b, which lowers a second lever m; the falling m lowers g, and g raises the catch f on high to unlock its nose. The springs then return the joints to their original positions.
Coupled motion: if a goes toward c, b goes toward n
A small figure states the linked motion of two members: when a moves toward c, b moves toward n.