Change Key
A master key operates a set of several locks. Usually, there is nothing special about the key itself, but rather the locks into which it will fit. These master-keyed locks are configured to operate with two, or more, different keys: one specific to each lock (the change key), which cannot operate any of the others in the set, and the master key, which operates all the locks in the set. Locks that have master keys have a second set of the mechanism used to operate them that is identical to all of the others in the set of locks. For example, master keyed pin tumbler locks often have two shear points at each pin position, one for the change key and one for the master key. A far more secure (and more expensive) system has two cylinders in each lock, one for the change key and one for the master key. Master keyed lock systems generally reduce overall security. The fact that some pin chambers have two shear points allows for more options when picking and it also allows for more keys t ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Master Key Turning In A Lock
Master or masters may refer to: Ranks or titles * Ascended master, a term used in the Theosophical religious tradition to refer to spiritually enlightened beings who in past incarnations were ordinary humans * Grandmaster (chess), National Master, International Master, FIDE Master, Candidate Master, all ranks of chess player *Grandmaster (martial arts) or Master, an honorary title * Grand master (order), a title denoting the head of an order or knighthood *Grand Master (Freemasonry), the head of a Grand Lodge and the highest rank of a Masonic organization *Maestro, an orchestral conductor, or the master within some other musical discipline *Master, a title of Jesus in the New Testament *Master or shipmaster, the sea captain of a merchant vessel * Master (college), head of a college * Master (form of address), an English honorific for boys and young men *Master (judiciary), a judicial official in the courts of common law jurisdictions *Master mariner, a licensed mariner who is qu ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Pin Tumbler Lock
The pin tumbler lock is a lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key. Pin tumblers are most commonly employed in cylinder locks, but may also be found in tubular pin tumbler locks (also known as radial locks or ace locks). History The first known example of a tumbler lock was found in the ruins of the Palace of Khorsabad built by king Sargon II (721–705 BC.) in Iraq.James, Peter, and I. J. Thorpe. Ancient Inventions. New York: Ballantine, 1994. Basic principles of the pin tumbler lock may date as far back as 2000 BC in Egypt; the lock consisted of a wooden post affixed to the door and a horizontal bolt that slid into the post. The bolt had vertical openings into which a set of pins fitted. These could be lifted, using a key, to a sufficient height to allow the bolt to move and unlock the door. This wooden lock was one of Egypt's major developments in domestic architecture during classical times. Such a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tree (graph Theory)
In graph theory In mathematics, graph theory is the study of ''graphs'', which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of '' vertices'' (also called ''nodes'' or ''points'') which are conne ..., a tree is an undirected graph in which any two Vertex (graph theory), vertices are connected by ''exactly one'' Path (graph theory), path, or equivalently a Connected graph, connected Cycle (graph theory), acyclic undirected graph. A forest is an undirected graph in which any two vertices are connected by ''at most one'' path, or equivalently an acyclic undirected graph, or equivalently a Disjoint union of graphs, disjoint union of trees. A polytreeSee . (or directed tree or oriented treeSee .See . or singly connected networkSee .) is a directed acyclic graph (DAG) whose underlying undirected graph is a tree. A polyforest (or directed forest or oriented forest) is a directed acyclic graph whose underlying undirecte ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Skeleton Key
A skeleton key (also known as a passkey) is a type of master Lock (security device), key in which the serrated edge has been removed in such a way that it can open numerous Lock and key, locks, most commonly the warded lock. The term derives from the fact that the key has been reduced to its essential parts. The term is also used synonymously with master key to refer to any key, keycard or other device capable of opening a variety of locks. Master keys A skeleton key is a key that has been filed or cut to create one that can be used to unlock a variety of warded locks each with a different configuration of wards. This can usually be done by removing most of the center of the key, allowing it to pass by the wards without interference, operating the lock. To counteract the illicit creation of such keys, locksmiths can put wards not just in the center but on the outside as well, making the creation of a skeleton key more difficult. Lever tumbler lock, Lever lock skeleton keys a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |