Lock And Keys

A lock is a mechanical fastening device which may be used on a door, vehicle, or container, restricting access to the area or property enclosed. Commonly, it can be released by using a key or combination. Next was developed a warded lock that is still used in modern times when the security required is not high and cost is a significant factor. It is the first lock design to have a key recognizable to a modern western person. Lock puzzles were used to obscure the locking mechanism or even provide a nonfunctioning lock for the thief to waste time on.

Locks may be entirely mechanical, or electromechanical. They may be operated by turning some form of removable key, by keying or dialling in a combination which directly or via electromechanical means operates the lock, with some form of magnetic or other card reader, or by moving a part on a safety lock intended to prevent accidental operation rather than to prevent unauthorized access. Early improvements in pin locks included increasing the number of pins to increase security, and changing the orientation of the pins to allow the key to provide the unlocking force instead of a rope. Thus establishing the principles of the modern pin tumbler lock.

A door is a moveable barrier used to cover an opening. Doors are used widely and are found in walls or partitions of a building or space, furniture such as cupboards, cages, vehicles, and containers. A door can be opened to give access and closed more or less securely using a combination of latches and locks. (See article Door security). Doors are nearly universal in buildings of all kinds, allowing passage between the inside and outside, and between internal rooms. When open, they admit ventilation and light. The door is used to control the physical atmosphere within a space by enclosing it, excluding air drafts, so that interiors may be more effectively heated or cooled. Doors are significant in preventing the spread of fire. They act as a barrier to noise.

A trapdoor is a door that is oriented horizontally in a floor or ceiling, often accessed via a ladder. Blast-proof doors are constructed to allow access to a structure but also to provide protection from the force of explosions. A garden door is any door that opens to a garden or backyard. It is often used specifically for double French doors in place of a sliding glass door. In such a configuration, it has the advantage of a very large opening for moving large objects in and out. A pet door (also known as a doggy door or cat flap) is an opening in a door to allow pets to enter and exit without the main door being opened. It may be simply covered by a rubber flap or it may be an actual door hinged on the top that the pet can push through. Pet doors may be mounted in a sliding glass door as a new (permanent or temporary) panel. Pet doors may be unidirectional, only allowing pets to exit. Pet doors may be electronic, only allowing pets with a special electronic tag to enter.