Linus Yale Jr.

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Linus Yale Jr.
Inventor of the Pin-Tumbler Lock and founder of Yale Lock Co.
Born(1821-04-04)April 4, 1821
Salisbury, New York, United States
DiedDecember 25, 1868(1868-12-25) (aged 47)
New York City, New York, United States
Burial placeArms Cemetery, Shelburne Falls, Massachusetts
OccupationInventor, mechanical engineer, businessman
Known forYale Lock
Yale Bank Lock
Yale Chilling Iron Safes and Vaults
Pin Tumbler Locks and Cylinder Locks
Spouse(s)Catherine Brooks Yale
ChildrenJohn Brooks Yale
Madelaine Yale Wynne
Julian Linus Yale
Parent(s)Linus Yale Sr.
Chlotilda Hopson Yale
AwardsNational Inventors Hall of Fame

Linus Yale Jr. (April 4, 1821 – December 25, 1868) was an American mechanical engineer, manufacturer, and co-founder of the Yale Lock Manufacturing Company. He is best known for his inventions of locks, especially the cylinder lock. His basic lock design is still widely distributed today, and constitutes a majority of personal locks and safes.


Youth and family[edit]

Linus Yale Jr. was born in Salisbury, New York. Yale's father, Linus Yale Sr., opened a lock shop in the 1840s in Newport, New York, specializing in bank locks. and his ancestors were of the same family as Elihu Yale, the benefactor to and namesake of the well known Yale University. Yale's father, Linus Yale Sr., was a successful inventor who owned a lock shop in the village of Newport, New York, and specialized in expensive, handmade bank locks and mechanical engineering, and who held eight patents for locks and another half dozen for threshing machines, sawmill head blocks, and millstone dressers.


After some regular education Yale soon joined his father in his business and introduced some revolutionary locks that utilized permutations and cylinders. In 1858, Yale's father died, and Linus Yale Jr. became more involved with his father's lock company.

Yale opened his own shop about 1860 in Shelburne Falls, Massachusetts, specializing in bank locks.

He later founded a company with Henry Robinson Towne in the South End section of Stamford, Connecticut, called the Yale Lock Manufacturing Company. Throughout his career in lock manufacturing, Yale acquired numerous patents for his inventions and received widespread acclaim from clients regarding his products.

Death and Legacy[edit]

On a business trip to New York City in 1868, the same year that the Yale Manufacturing Company was founded, Yale died suddenly of a heart attack while negotiating to have his locks installed in a skyscraper. By that time, his locks were already selling profusely, and under Towne's management Yale Locks became the premier manufacturer of locks in the United States.

Yale's Locks still play a major part in today's security systems. In his later years, Yale perfected the mechanism known as the "clock lock" and invented the double lock, which placed two locks within one case to be operated by the same or different combinations. His improvements in locks and boxes for the post-offices are of recognized utility and worldwide adoption. The commonly used combination locks omnipresent today also owe their dues to Linus Yale Jr.

In 2006 Yale was induced into the National Inventors Hall of Fame.


Portrait painting[edit]

Young Yale developed an early affinity for portrait painting, but about 1850 decided to assist his father in improving bank locks and to study mechanical problems. However, his finesse in drawing and sketching proved to be useful, as his diagrams on his later designs of locks were detailed and clear.

Locks and mechanisms[edit]

In the 1860s, around the time he had opened his own shop in Shelburne Falls, Massachusetts, Yale specialized in bank locks. He introduced some combination safe locks and key-operated cylinder locks that were improvements on previously used locks. Possessing admirable skills in mechanics and lock making, Yale created one of the first modern locks that used a pin-tumbler design. The pin-tumbler design is also known as the cylinder design, and plays significant roles in today's locks and safes. Yale had previously harbored the practical implementation of the tumbler lock for decades, and had sketched the idea in 1844. Yale was convinced that key holes in traditional locks made the locks susceptible to thieves who could use picks, gunpowder explosives, and heat to thwart the locks. This led him to employ permanent dial and shaft designs in his inventions, known as "combination locks" today. Yale's best-known lock design, the cylinder pin-tumbler lock, utilized a key-operated lock concept first conceived in ancient Egypt over 4,000 years ago[citation needed].

Yale's inventions were so successful and received such critical acclaim that he exhibited several of his lock designs at world's fairs in the United States and overseas, winning a number of awards at these exhibitions.

Throughout his career Yale acquired many patents, mostly related to his inventions of locks and safes, but also including mechanical problems. In 1858, he patented a device for adjusting at a right angle the joiners' square. In 1865 he patented a tool for reversing the motion of screw-taps. In 1868 he received two patents for improvements in mechanics' vises.[1]


Yale had many inventions to his name throughout his career, thoroughly revolutionizing the locks industry and improving the security of financial institutions. Drawing on the principles first put to use in large wooden locks built by ancient Egyptians[citation needed], Yale patented a pin tumbler lock for use in banks in 1851; he patented his pin tumbler lock for use in doors in 1863; in 1865 he patented the pin tumbler padlock, which are still widely used today. Yale's model of the padlock was smaller, sturdier, more reliable, and innovative, proving to be a distinction among locks of his day.

Listing of patents[edit]

Yale Bank Lock[edit]

In 1851 Yale invented what he referred to as the "Yale Magic Infallible Bank Lock", for safes and vaults. This design allowed the owner to change its combination and would also allow the key to secure the lock while being hidden away from the exterior of the door by a hardened steel plate, which covered the key-hole behind it.

Yale stated nine peculiarities for his Yale Magic Infallible Bank Lock that separated it from its peers: [1][citation needed]

  1. Being without springs, there are none to fail; it is impossible to damage by fire, dampness, or neglect. The design rid itself of the vices of the springs that become rusty or softening by heat or moisture.
  2. The lock has a head that is detached from its key-bits, thus leaving a space between the head and the key-hole, making it virtually impossible to be picked.
  3. When the key is withdrawn, all print or record of its action is obliterated, and no tell-tale left for duplicate keys to be made
  4. Powder proof. No powder can possible be introduced into the lock itself, which eliminates the threat of gunpowder explosions.
  5. Permutation lock has the ability to rearrange new key combinations.
  6. In the event of a lost key, a duplicate key can be set up to unlock the lock, and upon changing the arrangement of the lock, the lost key will be powerless to open the lock.
  7. The portability of the key conveys a vast advantage over traditional bank locks.
  8. Every motion of the lock is derived from movement of the hands rather than elements beyond the operator's control, such as dirt, rust, or memory.
  9. The lock is not liable to get out of order, having been made by first class machinists.

Other locks[edit]

Yale Safe Lock

Yale's second great invention came around 1863, which he coined the name "Yale’s Magic Infallible Safe/Door Lock". This lock has many of the scintillating qualities of the Yale Bank Lock, and is designed for fire-proof safes and cash doors, among other items. It does not utilize springs, and is powder, damp, fire, and thief proof. The lock is not, however, a permutation lock, but each lock is unique and two different locks can never be opened with the same key. In addition, the key must be withdrawn from the lock before the bolt can be unlocked, preventing the liability of carelessly leaving the key in the keyhole.

Yale Chilled Iron Vaults and Safes

Yale's other significant invention is the Chilled Iron Bank Doors and Vaults. Previous bank doors, vaults, and safes had plates of hard cast behind soft wrought iron, which can be easily broken using the right amount of leverage and skillful vault-picking. The hard casts are often rigid and fragile, and susceptible to heavy tinkering. Yale used a lattice screen, or basketwork of soft, tough wrought iron, instead of the hard cast, infused in the metal covering of the vaults, thus producing incomparably strong corners and surfaces that Yale presented to be unbreakable.

Yale Manufacturing Company[edit]

Yale & Towne Manufacturing Co, 1897.[2]

In 1868, Yale and Henry R. Towne founded the Yale Lock Manufacturing Company in Stamford, Connecticut, to produce cylinder locks.

Under Yale's ingenuity and wide promotion of his inventions, Yale Locks quickly spread around major corporations in the United States and were widely adopted. Among some of Yale's business tactics were exploiting the weaknesses in other locks and presenting how his were free of those vices; he did live demonstrations to corporate business executives and government officials that showed how he successfully picked the locks that were in operation. Due to these demonstrations and the sheer quality of Yale's locks, Yale Lock Manufacturing quickly gained business ground. The company's name was later changed to The Yale and Towne Manufacturing Company, which eventually became part of NACCO Industries.

Cracking the Hobbs Lock

The prominent bank locks of Yale's day were the Hobbs or Newell locks. In an effort to present his locks over the continued usage of the Hobbs Locks, Yale contacted notable bankers and set up a live demonstration in which he successfully picked a Hobbs Lock. As described by Samuel Hammond, one of the bankers present at Yale's demonstration, "[he] proved that the Hobbs lock is able to be picked and demonstrated it using a fake wooden key that he made". [1][citation needed]

Challenge to the World

As part of Yale's business plan and effort to promote his Bank Locks, Yale presented a challenge to anyone who dared to pick his bank locks. He offered a $3000 (a hefty sum) reward to potential challengers, in the event that his locks were successfully picked.


The utility of Yale Locks were soon widely approved and favored upon, and implemented by many firms and government agencies, including the U.S. Treasury Department, Mint of the U.S. in Philadelphia, Pennsylvania, among various CEOs and Presidents of major corporations. The clients' satisfaction in Yale's inventions was echoed in their appreciation letters addressed to Yale: [1][citation needed]

"Briggs Bank, Clyde, April 30, 1856
Linus Yale Jr.,
Dear Sir: *** About two months since, during a dark and stormy night, our bank was entered by burglars, through an adjoining cellar wall, and the vault, which was of brick, was pierced, which left us without any other protection than one of your highly approved chilled iron Burglar-Proof Safes, with your magic lock attached; these we deem sufficient, for they successfully resisted all the various devices and expedients known and practiced by burglars. We have the most implicit confidence in their strength and safety, and feel assured that when once locked, we are more secure than we should be with any other safe and lock ever yet invented.
Yours, respectfully,
WH. H. Coffin, Cashier".
"I am convinced to this knowledge of the true principles of locks has enabled [Yale], in his lock, to overcome not only this, but every other known method of picking; and, in fact, I consider it and all respects superior to any other lock in the market".
-Samuel Hammond. NY, January 12, 1856


  1. ^ "Linus Yale | Lemelson-MIT Program". Retrieved 2016-05-12.
  2. ^ Roland, Henry. "Six examples of successful shop management." Engineering Magazine 12. 1897

Further reading[edit]

  1. A dissertation on locks and lock picking, and the principles of burglar proofing: showing the advantages attending the use of the magic infallible bank lock, and the patent door lock, invented by Linus Yale Jr. ... and his patent chilled iron burglar-proof bank doors, vaults, and safes, which are adopted by the U.S. Treasury Department for all the new mints, custom-houses, and sub-treasuries in the United States; manufactured and sold by Linus Yale Jr. & Co. Philadelphia: T.K. and G Collins, Printers, 1856.
  2. "Locking Mechanisms". Inventor of the Week: Archive. Lemelson-MIT Program.
  3. "Linus Yale Jr". NNDB tracking the entire world. Soylent Communications.

External links[edit]