Hi,
Snaphaunce was a northern European invention that included a separate battery and pan cover, lateral sear (through the plate), and internal mainspring. The pan was opened automatically during firing by a push rod attached to the tumbler. Many snaphaunces were converted during the early 1600s to type 1 English locks by combining the pan cover and battery into a "single "frizzen" and eliminating the push rod, thus simplifying the mechanism. The name "miquelet" is a 19th century term that refers to the "Spanish" or "Mediterranean" lock that evolved during the late 16th century. Those locks had external main and frizzen springs, a combination battery and pan cover, lateral half and full cock sears moving through the lockplate, and a very sturdy and safe half cock mechanism. They had few internal parts and consequently, less wood was removed from the lock mortice compared with other locks. The throw of the cock was short and powered by a very strong main spring. The locks were very reliable and sturdy, which is why the Spanish held on to the design for a long time.
dave