Chubbs "Improved Patent" rimlock

[oldlock]

This is a fine example of a Chubbs Improved patent detector lock, it is very similar to all but the very earliest Chubb locks with the exception of one important modification, the earliest locks had a separate key to reset the detector, this key was called the regulating key and was soon found to be inconvenient and with the exception of special purpose locks for use in prisons the design was changed in favour of the improved patent.

This lock dates from circa April 1827



In common with most early Chubb locks it features two bolt stumps and two sets of gatings, one set being for the main bolt and the other for the detector. Any one of the levers, will if lifted beyond it's correct height, as it may be in an attempt to pick the lock move the detector bar and in doing so prevent the lock from being opened.



Here the detector arm is shown engaged, in this state the lock is fully locked and not even the correct key will open it until the detector is reset.



Here the key is being used as if to throw the lock again (it already being locked) in doing so the detector stump is moved into the gating and the detector is reset, returning the lock to normal operation.



The key shown below is not original, the dust plug in the end is however quite authentic for locks of this period. This lock has the distinction of being one of the earliest known Chubb locks, with only three older examples known to me at this time.