60 • HISTORYOFLOCKS
One in the Chamber:
The history of chamber locks
» » LOCKSMITHS DURING THE ‘AGE OF
enlightenment’ (14th – 18th centuries)
soon realised that a lock, to be successful
in its purpose, should have several
features or principles combined. The
tumbler acting as a catch to hold the bolt
in either the locked or unlocked position
combined with fixed wards evolved from
traditional spring barbs. The ward tumbler
though provided only basic security and
the ingenuity of locksmiths soon devised
enhancements. Like so many of these
enhancements, possession of the key
was not enough, the secret or sequence
also had to be known; a bit like modern
combination locks where even if the
combination number is known the method
of operation must also be known.
One such enhancement was the
double chamber.
A double chamber, in the context of
lock mechanisms, is where there are two
compartments or chambers for keys to
navigate in order to operate the lock;
each chamber requiring its own action
or sequence before proceeding on to
the next chamber; sometimes with the
same key, sometimes with a completely
different key. Needless to say and like so
many ‘lock’ ideas or principles there are
A side view of the chambers and
their respective bridge wards.
A chest lock
with two
chambers. Note
the link plate
with separate
sockets for top
and bottom
chambers.
The lock with
the cap removed
showing the top
chamber latch
bolt a, and the
lower chamber
dead bolt b.
almost as many variations as there were
locksmiths, each smith bringing his own
idea and variation; sometimes working
out the sequence to the uninitiated, even
when in possession of the correct keys,
can be quite challenging.
It’s not known who, where or when the
double chamber in locks first appeared;
although the padlock is an early contender.
The key holes in many pre-industrial locks
were upside down and usually this was
the first indicator of a double chamber. The
top chamber incorporated a barrel which
effectively blocked off any access to the
lower chamber.
The chest was very popular in the days
before iron and steel safes. Homes and
businesses had any number of lockable
containers of varying sizes, and each
supplied with a lock. The mechanisms
contained all sorts of secrets including
double chambers. In one example the
first or top chamber was in effect a key
operated latch, but an extra turn of the
key dead locked the latch and the lower
chamber, which used a completely different
key, was a double throw deadlocking bolt.
Interestingly the deadlocking for the lower
chamber was anti-clockwise, whilst the
top chamber was clockwise to deadlock.
The effect was that latch was used as a
day lock but the ‘master’ could deadlock it
effectively making the top chamber latch or
day lock ineffective.
Another unusual arrangement, this
time in a German (DR stamped into one
of the bolt heads) made rim deadlock
featuring two deadbolts each operated
from a different chamber. The top and
bottom chamber are operated with the
same key and the independent bolts
are both double throw; what might
confuse is that the top bolt is withdrawn
in the conventional way for the hand
(anti-clockwise) and the bottom bolt is
withdrawn as if locking (clockwise).
Davis of Windsor, Locksmith to King
George IV, looked after the ‘metal work’
including the clocks and locks on the
Windsor estate. He patented a double
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A large early European Padlock
(17th/18th century), weighing 2.724kg,
with a double chamber. In this example,
the key hole is protected with a flap,
which is released with a stiletto, and
to further confuse there are several
‘stiletto’ holes only one of which will
release the flap and even then the angle
and direction of insertion is critical.
Notice what appears to be an upside
down keyhole; a clue that this lock
incorporates two chambers. In this
example, the key is turned as if locking
(anti-clockwise) 180°, this rotates the
barrel, which also incorporates a shutter,
allowing the key, now the right way up to
enter the lower chamber. A reverse turn
(clockwise) finally releases the shackle.
chambered lock that was adopted for
ministerial purposes and is most often
found on the dispatch boxes of the day.
Indeed the keys had a certain feel or nicety
about them and were cherished. Ministers
very often requested these locks even
though the more secure locks by Bramah
and Chubb were now the norm.
Davis’ lock featured wards on the
outer key hole which didn’t fully
represent the wards on the inner key