Wafer tumbler lock

A wafer tumbler lock is a type of lock that uses a set of flat wafers to prevent the lock from opening unless the correct key is inserted. This type of lock is similar to the pin tumbler lock and works on a similar principle. However, unlike the pin tumbler lock, where each pin consists of two or more pieces, each wafer in the lock is a single piece. The wafer tumbler lock is often incorrectly referred to as a disc tumbler lock, which uses an entirely different mechanism.

The earliest record of the wafer tumbler lock in the United States is the patent in 1868 by Philo Felter. Manufactured in Cazenovia, New York, it used a flat double-bitted key. Felter's lock was patented only three years after Linus Yale, Jr. received a patent for his revolutionary pin tumbler mortise lock, considered to be the first pin tumbler lock of the modern era. That lock featured a flat steel key, referred to as a "feather key" because of the marked contrast with the heavy bit keys of the day. Just two years later, Hiram S. Shepardson produced a different type of wafer tumbler lock, which used a single-bitted flat steel key, similar to Yale's feather key.

By 1878, Yale Lock had purchased Shepardson's company, The United States Lock Company, as well as Felter's American Lock Manufacturing Company. For the next 35 years, production of wafer tumbler locks languished in the U. S. And while Felter and Shepardson had designed their wafer tumbler locks for a variety of applications such as drawer and desk locks as well as padlocks and door locks, the wafer tumbler locks made during this era were mainly used for doors in mortise locks and night-latches.

Emil Christoph developed a wafer tumbler lock in 1913 which used a double-bitted key. His patent was assigned to King Lock of Chicago, a new lock manufacturer. By 1915 Briggs & Stratton Corporation was using King wafer tumbler locks in their ignition switches. In 1919, Briggs & Stratton applied for a switch patent using a wafer tumbler lock of their own design, which used a double-bitted key. Five years later, Edward N. Jacobi of Briggs & Stratton filed for a patent for a five-wafer, single-bitted wafer tumbler lock. The first recorded use of this lock was for an automobile, the 1924 Hupp Eight.

In the UK, this type of lock was introduced by Josiah Parkes & Sons of Willenhall in 1929, who supplied them initially to the Wilmot Breeden company. Early units were stamped with a patent number on the keys, although it is not clear whether this referred to a U.S. patent or one taken out by JPS themselves. Wilmot Breeden combined leaf-tumbler barrels with parallel innovations in pressure diecasting and chromium-plating and thus became the major manufacture of vehicle body hardware in the UK nearly fifty years, supplying all of the country's vehicle manufacturers apart from Rolls Royce & Bentley who remained with pin-tumbler designs. Early WB key-types were branded 'MRA', 'NAX', and 'MRN', the latter being used universally until 1945. British competitors copied WB patterns, even duplicating the exact cut of their keys, necessitating changes to 'FA', 'FP', and 'FS', each having some variation in fluting, or key-section. All these barrels used single-sided keys until a 'double-entry' pattern was developed for Ford in 1962, and this quickly became the standard with motor manufacturers until the advent of higher-security barrels in 1968. The first of these was 'NH', with ten tumblers arranged five per side, which was required to meet new motor industry standards for security. Subsequently WB's more advanced 'WR' series also had ten tumblers but with an asymmetrical key. Development ceased with the effective demise of WB in 1982. <personal experience in senior management><WB company literature>

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