Locksmith

Locksmiths in the United States

Lock (fastening device), mechanical device used for fastening doors, chests, and lids, consisting of a bolt guarded by a mechanism released by a key or a combination.
The simplest form of lock is a ward lock, which is a bolt containing a notch known as a talon. The bolt is moved by engaging a key in the talon. The tumbler lock contains one or more pieces of metal of different heights, known as tumblers, which intercept the bolt and prevent it from being moved until the tumblers are raised or released by the action of a key. The pin-tumbler cylinder lock, or Yale lock, consists of a cylindrical plug that is rotated when the inserted key raises five pins of different sizes into corresponding holes in the plug; the plug moves the bolt by means of a cam. The magnetic lock needs a magnetized key to bring the pins into alignment. In the combination lock, a spindle rotated by a numbered or lettered dial on the outside of the lock actuates a set of tumblers and releases the bolt. Dating to ancient Egypt, locks did not significantly change until the 19th and 20th centuries. Today, development has focused on increasing the complexity of the working mechanisms, including the increasing use of automatic electronic alarm and safety devices.



Linus Yale, (1821-1868), American locksmith, who invented and manufactured the pin-tumbler cylinder lock, was born in Salisbury, New York. He learned how to design and make bank-vault locks from his father. Perceiving a great demand for smaller mass-produced locks, Yale experimented with different types of locking mechanisms. Eventually, he devised the cylinder lock, which was based on the pin-tumbler mechanism used by the ancient Egyptians. He obtained patents for his design in 1861. Yale's cylindrical pin-tumbler lock remains the most commonly used design in modern door locks and padlocks.
In Yale's cylindrical pin-tumbler locks, a serrated key is inserted into a cylinder that houses spring-loaded pins. The serrations on the key raise the pins. If the key raises all the pins to the proper height, the cylinder can be turned and the lock can be opened. Because the number of pins in the cylinder and the length and cross-sectional shape of the channel for the key can be varied, Yale's design provides for a large number of individual key shapes, each of which will open only one lock. At the same time, the Yale system allows for a specially designed master key that will open all of the locks of its series.
Yale also made improvements in bank locks. One of his improvements was the Yale Infallible Bank Lock. This lock's combination could be changed by separating and reassembling parts of the key. Yale improved on this bank lock in subsequent versions, eventually developing the Yale Double Treasury Bank Lock, one of the most secure bank locks operated by keys.
In 1862 Yale began to market his Monitor Bank Lock, the first combination bank lock. Combination locks quickly gained favor because vaults secured by them did not have keyholes that robbers could fill with explosives. In 1863 Yale developed the Yale Double Dial Bank Lock, which featured two combination locks.
In 1868 Yale entered a partnership with J. H. Towne and H. R. Towne to found the Yale Lock Manufacturing Company. He died later the same year.