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Security Locks


Security Locks
There are many types of locks available, but how do you decide which is the best to use?  Insurance companies and the police recommend a five lever mortice deadlock which has the British Standard 3621:1980 kite mark stamped on it.  In fact, many insurance companies now insist that if you want them to insure you, you must have (in addition to other requirements) the British Standard rating on your locks.  But what does all this mean, and why is it an important security device compared to other locks.
A British Standard deadlock must have the following:

  • A minimum of five levers
  • False Notching
  • Handles must not operate the deadbolt
  • The bolt must project no less than 14mm when locked
  • Both sides of lock must be protected by anti drill plates
  • Vulnerable fixing screws on all parts of the lock must be concealed when door is locked
  • There must be at least 1000 key variations

The mortice lock is very popular, and has been in existence for many years.  Chances are, you already have them fitted to your existing doors. A mortice lock is the type that has been designed to fit inside a door by means of a mortice  (A mortice is simply a woodworking term that describes a hole that has been cut into timber as part of a woodworking joint, hence the term 'mortice lock'), rather than the type designed to fit onto the door surface, such as the rim lock, rim cylinder lock, or night latch.
DeadlockGenerally speaking, there are two types of mortice locks that are used for external domestic properties; the mortice deadlock and the mortice sashlock.The mortice deadlock shown here on the left, fits into the door,Sashlock does not have handles, and operates by key only. When the door is closed, only the key hole or the plate that covers it (the escutcheon plate) can be seen. The locking action is achieved by a bolt that shoots out of the lock when the key is turned, which goes into a metal striker plate that is fitted into the doorframe. The locking bolt cannot be pushed or pulled back, (is not spring loaded) without using the key, so by unlocking it.  This feature where the locking bolt is fixed, is known as 'deadlocking', hence the term; deadlock. This type of lock would be used as a secondary device in addition to a lock with a latch action.
The sashlock works in the same way as the mortice deadlock having a key operated deadlocking action, but it also has a latch which is operated by door handles, which serves to hold the door closed without locking if required. When compared to the deadlock, the latch can be seen above the locking bolt as in this picture of the sashlock on the right. What should be remembered is, that the term 'deadlock' can be applied to both locks.

Security Locks Combinations
Combinations in locks gives greater flexibility and security.  Example combinations could be:
Front Door:  Two BS 3621 locks. A Cylinder rim lock, and a mortice deadlock. This would give security where the door is automatically locked when it is shut by means of the rim lock.  The mortice lock could then be used only when retiring for the evening or when going out and leaving the property empty. 
A sashlock with handles could be used at the centre of the door, with bolts top and bottom, the bolts could be surfaced mounted or the concealed type.
Alternatively, a sashlock with handles fitted at the centre of the door, with two mortice deadlocks, one at the top and bottom, all 'keyed alike' for convenience. 
Back Door:  BS 3621 sashlock and handles, with security bolts fitted top and bottom.
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