Padlock

Simple three-disc locking mechanism
from a wooden box recovered from
the Swedish ship Vasa, sunk in 1628

Medieval lock in Kathmandu

A lock is a mechanical or electronic fastening device which may be used on a door, vehicle, or container, restricting access to the area or enclosed property. Commonly, it can be released by using a key, keycard, RFID signal, or by inputting a keycode.

[edit] History of locks

Securing one's property has long been a concern of people throughout the world. Beyond hiding the objects or constantly guarding them the most frequently used option is to secure them with a device. Early solutions included knots to either detect, like the Thief knot, or hamper, like the Gordian Knot. Historians are unsure where the first lock was invented, but evidence suggests that locks initially developed independently in the Egyptian, Greek, and Roman civilizations. Wooden locks and keys were in use as early as 4,000 years ago in Assyria [1]. The first known lock with a key is a pin lock. The lock is strung on a rope hanging out of a hole in a door. A cylinder of wood with a hole drilled through its axis is the key, the length of the cylinder being the critical factor. The key is inserted into the hole and the bolt is pushed the correct distance. To lock the door the rope was pulled to extract the key cylinder, simultaneously pulling the bolt closed. This type of lock is still in use in certain parts of the world. Puerto Rico still uses this system. A disadvantage of this lock is that a vandal can push the rope into the hole — an ancient equivalent of putting glue into a lock.

Early improvements in pin locks included increasing the number of pins to increase security, and changing the orientation of the pins to allow the key to provide the unlocking force instead of a rope, thus establishing the principles of the modern pin tumbler lock.

Next was developed a warded lock that is still used in modern times when the security required is not high and cost is a significant factor. It is the first lock design to have a key recognizable to a modern western person. Lock puzzles were used to obscure the locking mechanism or even provide a non-functioning lock for the thief to waste time on.

[edit] Famous locksmiths

Chinese lock and key from Yunnan Province, early 20th century

• Robert Barron patented a double-acting tumbler lock in 1778, the first reasonable improvement in lock security.
• Joseph Bramah patented the safety lock in 1784. It was considered unpickable for 67 years until A.C. Hobbs picked it, taking over 50 hours.
• Jeremiah Chubb patented his detector lock in 1818. It won him the reward offered by the Government for a lock which could not be opened by any but its own key.
• James Sargent described the first successful key-changeable combination lock in 1857. His lock became popular with safe manufacturers and the United States Treasury Department. In 1873, he patented a time lock mechanism, the prototype for those used in contemporary bank vaults.
• Samuel Segal invented the first jimmy proof locks in 1916.
• Harry Soref founded the Master Lock Company in 1921 and patented an improved padlock in 1924 with a patent lock casing constructed out of laminated steel. Harry Soref was a big fan of japanese and used to call locks "joumae" which is the japanese name for locks. Also written as じょうまえ.
• Linus Yale, Sr. invented a pin tumbler lock in 1848.
• Linus Yale, Jr. improved upon his father's lock in 1861, using a smaller, flat key with serrated edges that is the basis of modern pin-tumbler locks. Yale developed the modern combination lock in 1862.

[edit] Types of locks

A type of padlock side view.

Door with two locks, one in the door knob and a separate deadbolt.

A typical combination lock.

Locks may be entirely mechanical, or electromechanical. They may be operated by turning some form of removable key, by keying or dialling in a combination which directly or via electromechanical means operates the lock, with some form of magnetic or other card reader, or by moving a part on a safety lock intended to prevent accidental operation rather than to prevent unauthorized access.

[edit] Pin-Tumbler locks

The Pin tumbler lock is the most widespread lock in the western world. ^[1] Pin-tumbler locks have been around in some form since 2000 B.C. The Egyptian form of this lock was large, heavy, and made of wood, with pins made of metal, usually bronze, but sometimes iron. This design in its modern form was first patented in 1805 in England. The patent holder was an American named A.O. Stansbury. In the middle of the 18th century, the American locksmiths Linus Yale Sr. and his son, Linus Yale Jr., refined the lock design into the form recognizable today. These early versions of the pin-tumbler lock were expensive to produce, and did not become widely available until mass production became feasible.

[edit] Wafer locks

The wafer lock is also known as the disc tumbler lock. The first patent for this type of lock was issued in the United States in 1868 to P.S. Felter. ^[2]The wafer lock is relatively inexpensive to produce and is often used in automobiles and cabinetry. This type of lock is generally made of die-casted zinc alloy.

[edit] Lever locks

Lever locks were invented in Europe in the 17th century. ^[3]This is a popular lock type for safes, as they are generally built of strong materials. They are also used as door locks in some countries. This is the type of lock that replaced the medieval warded lock in the 19th century. Robert Barron of England patented the double-acting lever in 1778. Jeremiah Chub would follow with his own detector lock in 1818.

[edit] List of common locks

• Bicycle lock
• Cam lock
• Chamber Lock
• Child safety lock
• Combination lock
• Cruciform (or Zeiss) lock
• Cylinder lock
• Deadbolt
• Disc tumbler lock
• Electronic lock
  • Electric strike
  • Magnetic lock
• Keycard lock
• Lever tumbler lock
  • Chubb detector lock
  • Protector lock
• Magnetic keyed lock
• Padlock
• Pin tumbler lock
• Police Lock
• RFID lock
• Rim lock
• Security door locks
• Tubular pin tumbler lock
• Time lock
• Turner lock
• Wafer tumbler lock
• Warded lock

[edit] See also

Wikimedia Commons has media related to: Locks

• Key relevance
• Lock picking
• Locksmithing
• Physical security
• Bored cylindrical lock and Mortice lock, two different approaches to locking mechanisms
• Exit control lock

[edit] Footnotes

[edit] References

• Phillips, Bill. (2005). The Complete Book of Locks and Locksmithing. McGraw-Hill. ISBN 0071448292.
• Pulford, Graham W. (2007). High-Security Mechanical Locks : An Encyclopedic Reference. Elsevier. ISBN 0750684372
• Alth, Max (1972). All About Locks and Locksmithing. Penguin. ISBN 0801501512
• Robinson, Robert L. (1973). Complete Course in Professional Locksmithing Nelson-Hall. ISBN 091101215X