Linus Yale Sr. and Linus Yale Jr.: Bank Locks and the Pin-Tumbler Cylinder

Linus Yale Sr.

Wikipedia gives Linus Yale Sr.'s dates as 27 April 1797 to 8 August 1858, and says he was the first mayor of Newport, New York. The brand history published by YaleHome says that around 1840 he began designing and making high-security locks at his Yale Lock Shop in Newport, specialising in expensive, handmade bank locks. Wikipedia's article on his son says the father held eight patents for locks and about another half-dozen for threshing machines, sawmill head blocks, and millstone dressers.

The YaleHome list of Yale patents opens with Linus Yale Sr.:

• 20 October 1843, No. 3,312, a combination lock (Springfield, Massachusetts, with C. Wilson);
• 13 June 1844, No. 3,630, a pin-tumbler lock (Springfield);
• 13 February 1849, No. 6,111, a safe (Newport, New York);
• several bank-lock and padlock patents through the 1850s.

The 1844 Patent

U.S. Patent 3,630, dated 13 June 1844, is titled "Door-Lock." It was issued to "Linus Yale, of Springfield," Massachusetts. The patent itself does not say Sr. or Jr.; the YaleHome list assigns it to the father. It describes the following:

• a cylindrical socket fixed inside the lock, pierced around its rim with holes for "pistons";
• a revolving inner cylinder with matching holes;
• a key in the form of a spindle with wedge-shaped grooves of different depths.

When the right key is inserted, it moves each piston by the right amount. The pistons then no longer bridge the joint between the fixed socket and the revolving cylinder, and the cylinder can turn. The patent notes that because the pistons are all of different lengths and must be moved different distances, "the picking of the lock becomes very difficult." Here, in early form, are the basic parts of a pin-tumbler cylinder: a rotating plug, pins of different lengths, and a key that sets them all at once.

The 1844 key is not the flat, serrated key of later Yale locks. That came with the son's patents.

Linus Yale Jr.

Linus Yale Jr. was born in Salisbury, New York, on 4 April 1821 (Lemelson-MIT; Wikipedia). Both Lemelson-MIT and Wikipedia say he first trained seriously as a portrait painter. Around 1850 he turned instead to mechanical problems and his father's lock business. The YaleHome history says he joined his father in 1850.

His early work was in bank locks. Lemelson-MIT credits him with an 1851 "Infallible Bank Lock" whose owner could change the combination. Wikipedia says he founded the Yale & Greenleaf Lock Co. in 1857 with Halbert S. Greenleaf. Greenleaf later went into partnership with James Sargent. After his father's death in 1858, Yale Jr. set up his own shop in Shelburne Falls, Massachusetts, around 1860 (Wikipedia; Lemelson-MIT). The Linda Hall Library reports that after the Great Exhibition of 1851, Linus Yale picked the Parautoptic lock that Alfred Hobbs had shown in London.

The 1861 and 1865 Cylinder-Lock Patents

Two patents by Linus Yale Jr. are usually cited for the modern cylinder lock:

• U.S. 31,278, 29 January 1861. It was issued to Linus Yale Jr. "of the city and county of Philadelphia" for an improvement in locks for drawers, closets, and cupboards. It describes a lock with a revolving tumbler, or plug, a key hole, and a row of pins with drivers and springs set in drilled holes. With the right key in place, the pins line up and the plug can rotate.
• U.S. 48,475, 27 June 1865. It was issued to Linus Yale Jr. of Shelburne Falls, Massachusetts. It is classified under cylinder locks with tumbler pins set by pushing in the key.

The Stamford Historical Society says the Yale Lock Company's success rested on "the cylinder or five-pin tumbler lock patented by Linus Yale in 1861." The YaleHome history cites patents granted in 1861 and 1865 together. Wikipedia gives a different sequence: a bank pin-tumbler lock in 1851, a door lock in 1863, and a padlock in 1865. This article describes the two patents above from their own texts. It does not name one of them as "the" Yale lock.

The family question is also not settled. YaleHome says the son "perfected and patented his father's pin tumbler cylinder lock." The patents themselves show the father's 1844 revolving cylinder with pistons, and the son's 1861 and 1865 pin-and-driver cylinders. How much of the later design came from the father is a matter of interpretation.

Stamford and Henry Towne

The Stamford Historical Society describes how the business moved. Linus Yale Jr. and the engineer Henry R. Towne had started a lock-making partnership in Shelburne Falls. In 1868 they chose a site in Stamford's South End, between the canal and the railroad. The firm was first called the Yale Lock Company. Yale died suddenly in December 1868. The Stamford Historical Society gives Christmas Day, while the UConn archives give 24 December, in New York. Towne went ahead with the factory, which opened in May 1869. He later took sole ownership and in 1883 renamed the firm the Yale & Towne Manufacturing Company. See Yale & Towne for the company's later history.

Legacy

The Yale cylinder combined a compact plug, spring-driven pin stacks, and a small flat key. It could be made cheaply and in very large numbers. Later systems keep that basic layout, including master keying, interchangeable cores, security pins, and high-security locks. Very different mechanisms, from Bramah's sliders to Abloy's rotating discs, show how many other ways there are to solve the same problem. For older pin locks, see ancient locks and Egyptian locks.

Related Topics

• Pin Tumbler Lock
• Yale & Towne
• James Sargent
• Combination Lock
• Padlock
• Walter Schlage
• Wafer locks

Sources