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Types of Door Locks

Mortice Locks

Basically there are two types of mortise locks that should be fitted to an external door,one is a sash lock and the other is a dead lock both are five  lever and carry the British standard kite mark.
A mortice lock is fitted into the edge of the door and when the key is turned a bolt is thrown into a keep which has been fitted into the door frame .A sash lock (pictured above) not only has the bolt with which you lock the door with, but also has a latch which keeps the door shut when locking is not  necessary. This type of lock will need a pair of handles to operate the latch to open and shut the door. The second type of mortise is the dead lock (pictured right) which has not got latch to hold the door closed just the bolt to lock the door.There are a lot of makes of mortise locks on the market, but by far the best are stamped with the British standard kite mark.

Simple nightlatchNightlatch locks commonly referred to as a yale lock. T  latch bolt to lock door, the bolt is automatically engaged with the locks keep, located on door frame, when the door is closed.  Nightlatches are available in many styles to suite door and security requirements.  A simple nightlatch(showen right) is the most basic type of nightlatch,  when the door is closed the bolt engages with the lock keep, the lock can then be operated by key from outside or a knob from inside to release the bolt and open the door.  A snib (a small sliding catch) is located on the lock case, this can be used to deadlock the bolt in the locked or unlocked position.

Simple nightlatchNightlatch locks use a large latch bolt to lock door, the bolt is automatically engaged with the locks keep, located on door frame, when the door is closed.  Nightlatches are available in many styles to suite door and security requirements.  A simple nightlatch(showen right) is the most basic type of nightlatch,  when the door is closed the bolt engages with the lock keep, the lock can then be operated by key from outside or a knob from inside to release the bolt and open the door.  A snib (a small sliding catch) is located on the lock case, this can be used to deadlock the bolt in the locked or unlocked position.

Deadlocking nightlatches operate in a very similar method but with the addition of the deadlocking feature via a key from the outside, thus allowing the door to be deadlocked whilst away from the premises.

Auto deadlocking nightlatches offer a third locking option, an extra deadlocking pin is located just above or below the main bolt, when the door is closed, this pin is depressed into the lock case automatically deadlocking the bolt.

Other types of nightlatch include Deadbolts and Rollerbolts, both of which operate in a similar method.

Nightlatch deadbolts use a solid bolt to lock, this is withdrawn by a key from outside or a handle from inside, some nightlatch deadbolts also include a latching system, this holds the deadbolt in the withdrawn position until the door is closed again.

Nightlatch rollerboltNightlatch rollerbolts (shown right) use a spring loaded deadbolt with a roller on the leading edge of bolt, which allows a door to be held in the closed position without locking, the door can then be opened with a simple push or pull and locked by extending the bolt into the keep with a key from outside or handle from inside.

Similar to mortice locks, rim locks are also available in simple dead and sashlock variants.  This type of lock is considered of low security, only suitable for internal use, and often found on period style doors.

British Standard locks should be used on all external doors, look out for locks with the BS3621:2007 certification.

Tony Richardson

Tony is an expert with over 20 years experience in the field. He provides services to a wide range of customers across Leicestershire, both residential and commercial.

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