Improvements in Door Locks.
Year: 1899

page_text: Date of Application, 16th Nov., 1899-Accepted, 20th Jan., 1900
Improvements in Door Locks.
I, FRANCIS JOSEPH JAMES GIBBONS, of St. John's Works, Church Lane, Wolver-.
hampton, in the County of Stafford, Lock Manufacturer, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to improvements. in door locks and more particularly to
locks having two key-holes of different size to suit the requirements of an asylum
or the like where master's as well as servants' keys are employed. The objects of
it are: To render it impossible for the servants or ordinary keys to unlock the
locks after the master's key has been in and double-locked or further shot the
bolt; and, (2) to prevent a sub-master key operating the servants lock through
the servants' or ordinary keyhole.
I will now proceed to describe my invention in detail, reference being had to
the accompanying drawing illustrating same, and in which:-
Figure 1 is a plan view of a two-keyhole dead-bolt lock with the cover plate
removed, the mechanism being in the position it assumes when single-locked.
Figure 2 is a plan view of the servants' or ordinary key, as used in the lock
shown in Figure 1.
Figure 3 is a plan view of the master key as used in the lock shown in
Figure 1.
Figure 4 is a plan view of the special drop-lever or guard plate, detached.
Figure is a front view of the outside of the lock, showing the special bosses
around the keyholes.
Figure 6 is a longitudinal section of Figure 5, the section being taken through
the special bosses and keyholes.
Figure 7 is plan view of a two-keyhole spring-pressed bolt lock with the cover
plate removed the mechanism being in the position it assumes when it is locked.
or has been operated by the master key.
Figure 8 is a plan view of the servants' key as used in the lock shown in
Figures 5 and 7.
Figure 9 is a plan view of the master or sub-master key as used in the lock
shown in Figures 5 and 7.
In order to clearly explain and show the application of this invention to a
lock, a two-keyhole lock has been selected for illustration, and the lock mechanism
shown in detail assembled.
The improvement which prevents the servant from being able to open the lock
after the master's key has been used in it, consists in the provision of a
drop-lever, or guard plate, such as shown detached in Figure 4, which lever
is raised at the same time and by the same means as the ordinary levers of the
lock, and by means of the specially formed gatings in said drop-lever it is caused
to fall much further down than the ordinary levers after the master-key has been
in and shot the blot subsequent to the locking of the lock by the servant, as is
more fully explained further on.
The improvement which prevents a master or sub-master from opening a lock:

page_text: by way of the servants' or ordinary keyhole, consists in making the substance in
which the keyhole is formed, much thicker than usual, so that the keyhole is much
deeper, this being effected by forming bosses on the cover plate around the key-
holes as clearly shown in Figures 5, 6, 8 and 9. The way they co-operate to attain
the result is fully described further on.
I will now proceed to more fully describe the invention simultaneously with its
operation in connection with the form of lock shown. As regards the drop-
lever: It consists of a flat plate o of substantially the same form as the ordinary
levers ce¹ of the lock. It has gatings cut in it in such manner that the ordinary
key will only raise it and shoot the bolt to a certain extent but not cause the
drop-lever to fall lower than the other levers, and such that when after the
servant's key has been used to. single-lock the lock the master or sub-master
key by further shooting the bolt brings a stump or projection on the bolt to
coincide with a long gating in the drop-lever which permits the latter to drop
much lower than the other levers, in fact sufficiently low to cover over the servants'
or ordinary keyhole. The gatings referred to are denoted by the letters i¹³
and j, the latter being the long one which permits the lever to drop lower than the
others. This drop-lever may be caused to drop by its weight, that is by gravity,
or, and this is the preferable way, it may be spring pressed like the other levers
as shown by the spring s so that normally it is thereby pressed downwards against
the stump on the bolt. This drop-lever is pivoted on the pin which passes
through a slot in the tail end of the bolt and is fixed to the casing, so that said
pivot is a fixture and consequently the drop-lever can only be moved up and down
turning on said pivot.
·
I will now proceed to describe the operation of the drop-lever: When the lock
shown in Figure 1, which is a dead-bolt lock, is unlocked, the' stump h will be
resting in the notch i of the levers and the bolt e will then of course be in its
retracted position. The servants' key is purposely made large so that it can only
be inserted in the proper keyhole which is denoted in these drawings by b. On
the servants' key being inserted in this keyhole and turned in the usual manner
the bit of the key comes in contact with the lower edges of the levers, the drop-
lever included, and also engages in the notch, in the lower edge of the bolt thereby
raising the said levers and advancing the bolt as far as the key will carry it;
drawing with it of course the stump e which it bears, through the passage-gating
and bringing the stump to rest in such position as to coincide with the gating i
of the levers, which latter thereupon drop down on to said stump assisted in this
motion by their springs s, s. The servants' key cannot further operate the lock
which now is only single-locked. The master or sub-master key shown detached
in Figure 3, can however, be employed to further lock the lock and prevent the
servant from unlocking it. This key is, as will be seen, made smaller than the
servants' keys and likewise the keyhole f which it fits. On inserting it in said
keyhole and turning it the bit of the key becomes engaged in the other notch n¹
in the lower edge of the bolt and the lower edges of the levers, raises the latter
and moves the bolt still further forwards until the stump h coincides with the
long slot or gating in the drop-lever, when the latter immediately drops down
together with the other levers, but much lower down than they can because they
are not possessed of a similar long gating therefore they only drop to the normal
extent whilst the special one o drops sufficiently low down for its nose o¹ to cover
over the keyhole b, and thereby prevent the servants' key being again inserted
in the lock to open it, until the master key has been again inserted, and raised
the drop-lever or guard-plate o, and retracted the bolt sufficiently far back for the
servants key to reach the notch .
In Figure is shown a spring-pressed bolt lock wherein the two keyholes are
in opposite sides of the lock, one of them passing completely through the lock
and the other only through the front plate. There is also an auxiliary locking
bolt which is operated by the keys and in turn operates the ordinary bolt e¹. The
operations of the keys are similar to those described with reference to the lock

page_text: shown in Figure 1 except that the key engages in the bolt instead of directly
in the bolt e. The figure shows the locked condition of the lock.
The means by which a master's or sub-master's key is prevented from being
inserted in the servants' keyhole sufficiently far to operate the locks by that way
notwithstanding that the master or sub-master key the smaller, is as follows:-
The depths of the two keyholes are not the same, one, preferably the servants',
being made deeper. This extra depth can be advantageously effected by casting
or otherwise forming a boss on the cover plate around the keyholes as shown in
Figures 5, 6, 8 and 9. The stop-collar von the key is also arranged so that it will
not permit the key to enter beyond a certain distance. The result is that if the
master or sub-master key be inserted in the servants' keyhole, the collar on the
key will not permit it to enter far enough to enable it to be turned on the ward
and so cannot operate the lock.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In a door lock, the combination with the ordinary levers, of a pivoted drop-
lever or guard-plate having gatings substantially as and for the purpose described.
2. In a door lock, the combination with the cover plate, of bored bushes or
bosses, constituting keyholes of different depths in the same lock, substantially
as and for the purpose described.
1000
PHILLIPS & LEIGH,
Agents for the Applicant.
22, Southampton Buildings, Chancery Lane, London, W.C.,