Lock and key
A lock is a mechanical or electronic fastening device that is released by a physical object (such as a key, keycard, fingerprint, RFID card, security token or coin), by supplying secret information (such as a number or letter permutation or password), by a combination thereof, or it may only be able to be opened from one side, such as a door chain.
Locks have been in use for over 6000 years, with one early example discovered in the ruins of Nineveh, the capital of ancient Assyria.
When the key was inserted, pins within the fixture were lifted out of drilled holes within the bolt, allowing it to move.
[1] 'The Romans invented metal locks and keys and the system of security provided by wards.
'[4] Affluent Romans often kept their valuables in secure locked boxes within their households, and wore the keys as rings on their fingers.
The practice had two benefits: It kept the key handy at all times, while signaling that the wearer was wealthy and important enough to have money and jewellery worth securing.
[9][10] With the onset of the Industrial Revolution in the late 18th century and the concomitant development of precision engineering and component standardization, locks and keys were manufactured with increasing complexity and sophistication.
[12] A burglary in Portsmouth Dockyard prompted the British Government to announce a competition to produce a lock that could be opened only with its own key.
The designs of Barron and Chubb were based on the use of movable levers, but Joseph Bramah, a prolific inventor, developed an alternative method in 1784.
As the key slides into the lock, the horizontal grooves on the blade align with the wards in the keyway allowing or denying entry to the cylinder.
A series of pointed teeth and notches on the blade, called bittings, then allow pins to move up and down until they are in line with the shear line of the inner and outer cylinder, allowing the cylinder or cam to rotate freely and the lock to open.
In its simplest form, lifting the tumbler above a certain height will allow the bolt to slide past.
An electronic lock works by means of an electric current and is usually connected to an access control system.
The lock in a typical remote keyless system operates with a smart key radio transmitter.
Generally the car door can be opened with either a valid code by radio transmission, or with a (non-electronic) pin tumbler key.
The ignition switch may require a transponder car key to both open a pin tumbler lock and also transmit a valid code by radio transmission.
[citation needed] Historically, locksmiths constructed or repaired an entire lock, including its constituent parts.
Many locksmiths also work on any existing door hardware, including door closers, hinges, electric strikes, and frame repairs, or service electronic locks by making keys for transponder-equipped vehicles and implementing access control systems.
Locksmiths are frequently required to determine the level of risk to an individual or institution and then recommend and implement appropriate combinations of equipment and policies to create a "security layer" that exceeds the reasonable gain of an intruder.
