The Schlage lock is actually a completely different concept of a cylindrical lock with the button in the knob mechanism placed between the knobs. This was introduced by Walter Schlage in the 1920s. Interestingly, as lock picking became an art in the 18th century, the inventor met the challenge of the burglar by introducing more complicated and complex locking mechanisms.
As such, an auto locksmith can sometimes be needed, as people take the security of their cars very seriously. Car locksmiths and car key locksmiths can be needed when people lose keys or lock the keys inside the doors. The first all metal lock appeared between 870 and 900, and was attributed to English craftsmen. Today, every lock is pretty much metal, except for old antique locks wit