Great find Raf, it seems to describe the monk's gun operating with pyrite as has been discussed, with linear & oblique cuts to the friction surface. Fig. 52 is a cannon lock from the 18th century with nearly identical construction, while 54 & 55 are spring driven friction bar systems from the 17th & 16th centuries respectively. This is what I gleamed using machine translation, and I can't find any opinions in the text regarding the efficacy of the device.
What I'm most curious about now is Fig.56 from that book, which shows an early 16th century lock where the friction surface is the segment of an arc. Functionally this would be the missing link between the linear bar & wheel, but not necessarily chronologically.
