Patented 6th December 1886, This example Circa 1899.
This is an example of the Chatwood Changeable safe lock. There is another version but it is far rarer and unlikely to be encountered. A unique feature of Chatwood changeable locks, either key or combination is that the changing mechanism is itself controlled by a further keylock, in this case a four lever lock mounted on the back of lock case.
In common with other Chatwood locks this lock has the Chatwood anti-pressure device to frustrate attempts to pick it. In it’s normal state the lock is key retaining and the round ‘ levers ’ are meshed with the top levers according to the pattern of the key the lock is currently set to.
Originally the lock would have been supplied with a number of keys, a set of 6 keys for duty or day managers and a changeable bit key for senior managers.
A set of keys is shown below.
Here the back view of the lock is shown, the keyhole is for the change key as detailed above.
The resetting of the lock is as follows :
1: Open the lock with the current key and leave the key turned.
2: Insert and turn the changekey in the rear keyhole. This will separate the mesh on the levers and hold the lower wheels with the bolt stump in the gate.
3: Turn the current key back and remove it.
4: Insert the desired key and turn to the unlocked position.
5: Now turn the changekey back and remove, this will mesh the two sets of levers and the lock is now set.
Here the changeable bit key is shown, above in it’s complete state and below disassembled ready for setting.
