Leonardo's snap lock. The missing link ?

[Raf]

Apologies for reviving an old thread

I stumbled across it while researching this drawing from Leonardo’s Madrid MS on the basis that it might be dateable evidence of an early fumbling towards a snapping type self – igniting lock. It has many features of flintlock type locks even though it is evidently simply a snapping matchlock with an automatically opening pan. What seemed interesting is that in theory if a flint replaced the match holding serpentine and the pan cover was made to act as the steel with a bit of adjustment it could be made to function as a flintlock. In investigating the geometry to see if the serpentines could be contrived to strike one another while still being controlled by the link I made what I thought at the time was an interesting, but in retrospect, fairly obvious realization. That the moving point of contact of two arcs traveling at the same speed; one being the flint and the other the hinged steel actually describes a straight line. Hardly surprising since of course this line represents the striking face of the steel common to all snapping type locks.

The geometry of Leonardo’s link illustrates very clearly the correct relationship between flints and steel that forms the theoretical basis of all snapping type locks. Leonardo certainly had the nous to appreciate the possible implications of the geometry but whether he ever applied it in this way is simply conjecture. But it perhaps ought to be recognized that it might be an important stage in the development of the idea.

So would a flintlock type lock with a fixed link like this actually work? The answer would appear to be possibly, but not very well. Mainly because of the practical difficulty in maintaining the correct radius of the flint in order to make good frictional contact with the steel. However experimentation with this idea could have given rise to an understanding of the geometry of snapping type locks and might be tentative evidence that the idea was being experimented with or was already known at this relatively early date (1490- 1498).
Suggesting that we should perhaps not be too confident in assuming that the early references (1507 to 1520) to self firing or little stone guns necessarily referred only to Wheelock’s.

Anybody want to develop this idea?