Combination locks
   HOME

TheInfoList



OR:

A combination lock is a type of locking device in which a
sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is cal ...
of symbols, usually numbers, is used to open the lock. The sequence may be entered using a single rotating dial which interacts with several discs or ''cams'', by using a set of several rotating discs with inscribed symbols which directly interact with the locking mechanism, or through an electronic or mechanical keypad. Types range from inexpensive three-digit luggage locks to high-security
safe A safe (also called a strongbox or coffer) is a secure lockable enclosure used for securing valuable objects against theft or fire. A safe is usually a hollow cuboid or cylinder, with one face being removable or hinged to form a door. The body ...
s. Unlike ordinary
padlock Padlocks are portable Lock (security device), locks with a shackle that may be passed through an opening (such as a chain, chain link, or hasp staple) to prevent wikt:use, use, theft, vandalism or harm. Naming and etymology The term '':wikt: ...
s, combination locks do not use keys.


History

The earliest known combination lock was excavated in a
Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of Roman civilization *Epistle to the Romans, shortened to Romans, a letter w ...
period tomb on the
Kerameikos Kerameikos (, ) also known by its latinization of names, Latinized form Ceramicus, is an area of Athens, Greece, located to the northwest of the Acropolis, Athens, Acropolis, which includes an extensive area both within and outside the ancient ci ...
,
Athens Athens ( ) is the Capital city, capital and List of cities and towns in Greece, largest city of Greece. A significant coastal urban area in the Mediterranean, Athens is also the capital of the Attica (region), Attica region and is the southe ...
. Attached to a small box, it featured several dials instead of keyholes. In 1206, the
Muslim Muslims () are people who adhere to Islam, a Monotheism, monotheistic religion belonging to the Abrahamic religions, Abrahamic tradition. They consider the Quran, the foundational religious text of Islam, to be the verbatim word of the God ...
engineer Ismail al-Jazari documented a combination lock in his book ''al-Ilm Wal-Amal al-Nafi Fi Sina'at al-Hiyal'' (''The Book of Knowledge of Ingenious Mechanical Devices'').Paul Vallely
How Islamic Inventors Changed the World
''
The Independent ''The Independent'' is a British online newspaper. It was established in 1986 as a national morning printed paper. Nicknamed the ''Indy'', it began as a broadsheet and changed to tabloid format in 2003. The last printed edition was publis ...
'', 11 March 2006.
Muhammad al-Asturlabi (ca. 1200) also made combination locks.
Gerolamo Cardano Gerolamo Cardano (; also Girolamo or Geronimo; ; ; 24 September 1501– 21 September 1576) was an Italian polymath whose interests and proficiencies ranged through those of mathematician, physician, biologist, physicist, chemist, astrologer, as ...
later described a combination lock in the 16th century. U.S. Patents regarding combination padlocks by J.B. Gray in 1841 and by J.E. Treat in 1869 describe themselves as improvements, suggesting that such mechanisms were already in use. Joseph Loch was said to have invented the modern combination lock for Tiffany's Jewelers in New York City, and from the 1870s to the early 1900s, made many more improvements in the designs and functions of such locks. However, his patent claim states: "I do not claim as my invention a tumbler composed of two disks, one working within the other, such not being my invention.", but there is no reference to prior art of this type of lock. The first commercially viable single-dial combination lock was patented on 1 February 1910 by John Junkunc, owner of American Lock Company.


Types


Multiple-dial locks

One of the simplest types of combination lock, often seen in low-security
bicycle A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered transport, human-powered or motorized bicycle, motor-assisted, bicycle pedal, pedal-driven, single-track vehicle, with two bicycle wheel, wheels attached to a ...
locks,
briefcase A briefcase or an attaché case (/əˈtæʃeɪ/) is a narrow hard-sided box-shaped bag or case used mainly for carrying papers and equipped with a handle. Lawyers commonly use briefcases to carry briefs to present to a court, hence the name. Bu ...
s, and
suitcase A suitcase is a form of baggage. It is a rectangular container with a handle and is typically used to carry one's clothes and other belongings while traveling. The first suitcases appeared in the late 19th century due to the increased popular ...
s, uses several rotating discs with notches cut into them. The lock is secured by a pin with several teeth on it which hook into the rotating discs. When the notches in the discs align with the teeth on the pin, the lock can be opened.


Single-dial locks

The rotary combination locks found on
padlock Padlocks are portable Lock (security device), locks with a shackle that may be passed through an opening (such as a chain, chain link, or hasp staple) to prevent wikt:use, use, theft, vandalism or harm. Naming and etymology The term '':wikt: ...
s, lockers, or
safe A safe (also called a strongbox or coffer) is a secure lockable enclosure used for securing valuable objects against theft or fire. A safe is usually a hollow cuboid or cylinder, with one face being removable or hinged to form a door. The body ...
s may use a single dial which interacts with several parallel discs or ''cams''. Customarily, a lock of this type is opened by rotating the dial clockwise to the first numeral, counterclockwise to the second, and so on in an alternating fashion until the last numeral is reached. The cams typically have an indentation or notch, and when the correct
permutation In mathematics, a permutation of a set can mean one of two different things: * an arrangement of its members in a sequence or linear order, or * the act or process of changing the linear order of an ordered set. An example of the first mean ...
is entered, the notches align, allowing the latch to fit into them and open the lock. The C. L. Gougler Keyless Locks Company manufactured locks for which the combination was a set number of audible clicks to the left and right, allowing them to be unlocked in darkness or by the vision-impaired. In 1978 a combination lock which could be set by the user to a sequence of his own choosing was invented by Andrew Elliot Rae. At this time the electronic keypad was invented and he was unable to get any manufacturers to back his mechanical lock for lockers, luggage, or brief-cases. The silicon chip locks never became popular due to the need for battery power to maintain their integrity. The patent expired and the original mechanical invention was instantly manufactured and sold worldwide mainly for luggage, lockers, and hotel safes. It is now a standard part of the luggage used by travellers.


Other designs

Many doors use combination locks which require the user to enter a numeric sequence on a
keypad A keypad is a block or pad of buttons set with an arrangement of digits, symbols, or alphabetical letters. Pads mostly containing numbers and used with computers are numeric keypads. Keypads are found on devices which require mainly numeric in ...
to gain entry. These special locks usually require the additional use of electronic circuitry, although purely mechanical keypad locks have been available since 1936. The chief advantage of this system is that multiple persons can be granted access without having to supply an expensive physical key to each person. Also, in case the key is compromised, "changing" the lock requires only configuring a new key code and informing the users, which will generally be cheaper and quicker than the same process for traditional key locks. Electronic combination locks, while generally safe from the attacks on their mechanical counterparts, suffer from their own set of flaws. If the arrangement of numbers is fixed, it is easy to determine the lock sequence by viewing several successful accesses. Similarly, the numbers in the combination (but not the actual sequence) may be determined by which keys show signs of recent use. More advanced electronic locks may scramble the numbers' locations randomly to prevent these attacks. There is a variation of the traditional dial based combination lock wherein the "secret" is encoded in an electronic microcontroller. These are popular for safe and bank vault doors where tradition tends towards dial locks rather than keys. They allow many valid combinations, one per authorized user, so changing one person's access has no effect on other users. These locks often have auditing features, recording which combination is used at what time for every opening. Power for the lock may be provided by a battery or by a tiny generator set in operation by spinning the dial.


Internal mechanisms

* A relock trigger, or internal relocker, is an integral part of the combination lock itself. It is usually designed to activate when the dial spindle is punched through. The trigger may consist of a spring-loaded lever or plunger that engages the bolt when the back cover is dislodged from the lock case. Some combination locks also are equipped with a thermal relock trigger that activates in the event of a torch attack. Nearly all safes made after World War II have relock triggers in their combination locks.


Manufacturers

*
ABUS August Bremicker Söhne KG, commonly known as ABUS, is a German manufacturer of security solutions, primarily preventative security technology. The company had remained headquartered in Wetter, North Rhine-Westphalia since its founding. It ...
*
Master Lock Master Lock is an American company that sells padlocks, combination locks, safes, and related security products. Now a subsidiary of Fortune Brands Innovations, Master Lock Company LLC was formed in 1921 by locksmithing, locksmith-inventor Harry ...
* Sargent & Greenleaf * Wordlock *Dudley * Conair *Kaba Mas *CJSJ


See also

*
Electronic lock An electronic lock (or electric lock) is a Lock (security device), locking device which operates by means of electric current. Electric locks are sometimes stand-alone with an electronic control assembly mounted directly to the lock. Electric lo ...
*
Password A password, sometimes called a passcode, is secret data, typically a string of characters, usually used to confirm a user's identity. Traditionally, passwords were expected to be memorized, but the large number of password-protected services t ...
*
Immobiliser An immobiliser or immobilizer is an electronic security device fitted to a motor vehicle that prevents the engine from being started unless the correct key (transponder or smart key) is present. This prevents the vehicle from being "Hotwiring ...
* Keycard


References


External links


How Combination Locks Work
HowStuffWorks.com {{DEFAULTSORT:Combination Lock Locks (security device) Locksmithing de:Schloss (Technik)#Zahlenschloss