"In this case necessity requires 3 springs, of which the first is responsible for the turning of the wheel, the second, for the thrusting of the stone against this wheel, and the third, for fixing this wheel, etc."
The striker is a flint stone instrument used for
repeatedly triggering a firearm. The device
is constituted of a helicoid spring connected,
by means of a jointed chain with three links,
to an upper wheel lodged in a ring and sustained at the center of a bridge with four arms screwed onto the ring itself. The wheel rubs against a piece of flint on the left. To the right is the trigger. With a turn of the wheel, the jointed chain stretches the large spring, loading the weapon. When the trigger is pressed, the stop tooth frees the wheel, which turns, striking the flint and igniting the gunpowder. The jointed chain, defined by Leonardo as "spring for the fire", is studied in another drawing (Codex Atlanticus, f. 987 r.) and moulded separately in larger scale.
The model is based on the drawing:
- Codex Atlanticus ff. 158 r., 987 r. (1497-1500)
Milano, Biblioteca Ambrosiana