Join Date: Nov 2013
... which of course makes a useful comparison with another early Italian lock you posted which I am re posting here. Uses the same long spring as a sear but is in this case released by a cam on the trigger rather than a button. Whats interesting about this lock is that the detent on the sear bar uses the same slot that operates the ( missing ) horizontally swivelling pan cover. Because the slot passes all the way through the wheel its highly unlikely to get blocked with rubbish therefore minimising the safety issues endemic to single locking bars.
Also the shape of the foot of the dog is very similar to the German lock which might be used to argue a much closer connection , at an early date between German and Italian locks even though Germany seems to have been quicker and better at developing the idea.
Iv'e never been convinced that Da Vincis drawing is , as some have argued , a device drawn from life and certainly isn't his unique invention. It looks more like a concept sketch of either a device he has seen , or has been described to him, or a device that he is trying to improve perhaps by suggesting that the parts could usefully be housed inside the lockplate. Placing the hinged locking bar on the outside of the lockplate is a clumsy solution , and the cranked mainspring simply silly. They may be drawn that way simply to make it easier to illustrate the principles involved so perhaps should not be taken to literally.