Wheellock

A wheellock, wheel-lock or wheel lock, is a friction-wheel mechanism to cause a spark for firing a firearm. It was the next major development in firearms technology after the matchlock and the first self-igniting firearm. The mechanism is so-called because it uses a rotating steel wheel to provide ignition. Developed around AD 1500, it was used alongside the matchlock and was later superseded by the snaplock (1540s), the snaphance (1560s) and the flintlock (c. 1600).

Design

The wheellock works by spinning a spring-loaded steel wheel against a piece of pyrite to generate intense sparks which ignite gunpowder in a pan, which flashes through a small touchhole to ignite the main charge in the firearm's barrel. The pyrite is clamped in vise jaws on a spring-loaded arm (or 'dog') which rests on the pan cover. When the trigger is pulled, the pan cover automatically opens, and the wheel spins as the pyrite is pressed into contact.

A close modern analogy of the wheellock mechanism is the operation of a modern cigarette lighter which spins a toothed steel wheel against a sparking material to ignite the fuel into a flame. However, the wheellock is used to send the flame to then ignite the charge in the barrel.