Antique Alphabet Padlock

Combination locks are a nearly millennium-old Arab invention. But it took several centuries before the idea reached Central Europe. Such locks involved a variety of mechanisms, and can be described as ring, roller, wheel or puzzle locks, as well as combination, letter, number or word locks. More physical puzzles could go by the name Vexier, which is a collective name for disentanglement puzzles.

Italian engineer Giovanni da Fontana was the first European to make a sketch of the Arab lock idea, back in 1420.

According to author Jon Millington, master locksmith Hans Bullmann (d. 1535) invented the letter lock, and a variant of it was invented by another master locksmith, Hans Ehemann (d. 1551). Both worked in Nuremberg, Germany.

In the next 300 years, not much happened with the original design. The locks of the 16th and 17th centuries use the same kind of hinged shackle.

It was the contribution of a French mechanic, Edme Regnier (d. 1825), that really made this kind of lock interesting. He doubled the number of rings, making it possible to change the combination.

Usually, this type of lock has 2–5 freely adjustable rings or other elements that release the shackle only when all of them are set to a specific position.