Electric strike

An electric strike is an access control device used for doors. It replaces the fixed strike faceplate often used with a latchbar (also known as a keeper). Like a fixed strike, it normally presents a ramped surface to the locking latch allowing the door to close and latch just like a fixed strike would. However, an electric strike's ramped surface can, upon command, pivot out of the way when the lock on the door is in the locked position and the door is opened, allowing a user to open the door without operating the mechanical lock or using a mechanical key. After the door is opened past the keeper, the keeper returns to its standard position and re-locks when power is removed or applied, depending upon the strike's configuration.

Electric strikes are generally available in two configurations:

Electric strikes are sometimes equipped with buzzers that allow someone outside the door to hear when the door is open. The buzzing noise is typically made by applying alternating current (AC) to the strike instead of direct current (DC). When using a DC powered strike, a buzzer accessory can be added to create the buzzing noise, if desired.

There are many manufacturers of electric strikes, and there are many things that have to be considered when buying one, i.e., type of jamb, type of locking hardware, whether one requires fail-secure or fail-safe, length of latch, depth of jamb, voltage requirements and the length of the faceplate. In some cases it is a good option to choose a magnetic lock.

Before using a magnetic lock, the Fire Marshal or appropriate authority should be consulted. There are emergency egress issues that must be addressed before using a magnetic lock.

Electric strikes can be differentiated in a number of ways, frame type it can be installed in, duty (continuous or intermittent), and which variety of locking mechanism on the door it can work with. The four most common locking mechanisms concerned with electric strikes are Cylindrical, Deadbolt, Mortise, and Rim Panic Exit Devices. Cylindrical locks tend towards residential use and, as such, electric strikes for cylindrical locks tends towards more economy. Deadbolts, also known as night latches, do not have a spring mechanism which means the strike for a deadlatch is 'hold' only (the dead bolt is thrown and it engages in the electric strike cavity, the electric strike can release it but cannot subsequently 'recapture it' since the deadbolt lacks the spring latching capability of the other lock sets). Mortise type locksets tend towards larger projecting latches from the door to engage deeper in the frame and electric strikes used for these locking mechanisms require more cutting and space in the frame. Rim Panic devices are required in many buildings as a 'single motion' means of egress and electric strikes used in these situations tend towards entirely different designs and opening actions as compared to electric strikes for other situations.

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Wikipedia