Inventive Ingenuity

As lock-picking became an art in the 18th century, the inventor met the challenge of the burglar with increasingly complicated locking mechanisms. Among the new improvements were keys with changeable bits, "curtain closed-out" around keyholes to prevent tampering, alarm bells combined with the action of the bolt, and "puzzle" or ring padlocks, with this principle developing into dial face and bank vault locks, operating without keys and known as combination locks.

The early puzzle padlocks were Oriental with from three to seven rings of characters or letters which released the hasp when properly aligned. The dial locks were similar in operation, and both types were combinated to unlock to words or patterns of numbers known only to the owners or responsible persons.

At the left is the Eureka, a manipulation-proof combination lock with five tumblers. For a faithful bank vault used at one time in the U.S. Treasury Department. Patented in 1862 by Dodds, MacNeal, and Urban of Canton, Ohio. The operating dial is a combination of letters and numbers and affords 1,073,741,824 combinations; to run through them all without interruption would take 2,042 years, 324 days, and 1 hour.