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An improved "shear" electromagnetic lock was patented on May 2, 1989, by Arthur, Richard and David Geringer of Security Door Controls, an access control hardware manufacturing firm. The device outlined in their designs was the same in principle as the modern magnetic lock consisting of an electromagnet and an armature plate.
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. [1] 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.
A tubular lock and key. A tubular pin tumbler lock, also known as a circle pin tumbler lock, radial lock, or the trademark Ace lock popularized by manufacturer Chicago Lock Company since 1933, is a variety of pin tumbler lock in which a number of pins are arranged in a circular pattern, and the corresponding key is tubular or cylindrical in shape.
The lock housing is the part of the lock that does not move when the lock is opened. It is responsible for transferring the action of the key to the bolt. [7] Master pin In a pin tumbler lock, a master pin is an optional, usually short, disk-like pin placed between the top and bottom pins. Its purpose is to allow two differently-cut keys to ...
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 ...
Locks are usually re keyed to build master-key systems, make a set of locks share a common key, or to eliminate compromised keys. [2] [3] [4] Sometimes worn pins are replaced with new pins if the old pins become too short to reach the shear-line. [5] The shear-line is the thin line shared by the lock plug and its cylindrical housing. If a pin ...
The Chubb detector lock is a variation of the lever lock which was designed to detect and prevent picking attempts. Lever locks can be drilled, but usually a template or stencil is required to mark the drilling point, as the lock mechanism is commonly mortised into the door and so it is harder to determine the point at which to drill.
This is a type of key where the individual cuts are designed to engage chisel-pointed pins in high-security locking systems manufactured by Medeco and Emhart. These angled cuts are designed to lift each tumbler to a predetermined height to the shear line and to rotate them to a specific angle to engage a sidebar mechanism (Medeco) (this is also used in Schlage Primus) or to line up an ...