Year: 1887

page_text: Date of Application, 17th June, 1887
Complete Left, 15th Mar., 1888
Complete Accepted, 1st June, 1888
I, STUART CARADOC MUNRO, of No. 25 York Street, Baker Street, in the County
of Middlesex, Gentleman, do hereby declare the nature of this Invention to be as
follows:-
This Invention relates to improvements in locks and in keys for opening and
closing same, the object being to prevent the lock from being tampered with by
means of false or skeleton keys and also to diminish the probability of the lock
being opened by an unauthorized person who may be in possession of the proper key.
The first of the above named objects is accomplished as follows:
:-
In the lock plate is formed a key hole in the usual manner preferably so arranged
that the key hole shall be vertical when the lock is fixed in position. Around that
part of the keyhole which is enlarged for the passage of the stem of the key is fixed
a short barrel having a flange at top and bottom, both the barrel and flanges being
slotted or cut away to allow the wards of the key to pass into the box of the
lock. At another part of the circumference of the barrel another slot is formed
to allow the wards to pass through a second keyhole formed in the lock plate which
is not visible when the lock is fixed. One or both of the keyholes may be totally
or partially closed by means of a sliding shutter fixed outside the lock plate, which
shutter is retained in position by a spring or spring and catch so arranged that the
shutter can only be released by means of a properly constructed key in the hands of
a person acquainted with the manner of using the same, the apparatus being so
constructed that unless pressure be applied to the key at the precise moment required
by the pattern of the lock, the key will continue to ride upon the upper flange of
the barrel outside the lock plate without penetrating into the interior of the lock.
If however the key be manipulated in such manner as to pass into the box of the
lock, the difficulty of opening the same is increased by forming a male thread on
the guide pin or stud over which the barrel of the key passes and a corresponding
female thread in the barrel of the key.
The screw may be either right or left hand and consist of several turns so as to
occupy some time before the wards of the key begin to act on the tumblers or

page_text: catches of the lock. The screw thread in the barrel of the key is concealed from
sight by means of a small piston which is kept in position by a spring so that there
is nothing in the appearance of the key to suggest that it differs from those of
ordinary construction.
The combination of difficulties presented by locks constructed according to my
Invention will be sufficient to defeat any attempt to open the same except by violence,
and it will be easy to construct the parts in such a manner that a person partially
acquainted with the mode of operation and in possession of the proper key would
probably break or displace some essential working part in a fruitless attempt to make
use of the same.
Dated this 17th dor of June 1887
HUGHES, ELI & HUGHES,
76, Chancery Lane, London, W.C.,
Agents for the Applicant.

page_text: I STUART CARADOC MUNRO 25 York Street Baker Street W. Merchant 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 locks and in keys for opening and
closing same the object being to prevent the lock from being tampered with by
means of false or skeleton keys and also to diminish the probability of the lock
being opened by an unauthorized person who may be in possession of the proper
key. The first of the above named objects is accomplished as follows.
In the lock plate is formed a key hole in the usual manner preferably so arranged
that the key hole shall be vertical when the lock is fixed in position. Around that
part of the key hole which is enlarged for the passage of the stem of the key is fixed
a short barrel having a flange at top and bottom, both the barrel and flanges
being slotted or cut away to allow the wards of the key to pass into the box of the
lock. At another part of the circumference of the barrel another slot is formed to
allow the wards to pass through a second key hole formed in the lock plate which is
not visible when the lock is fixed. One or both of the key holes may be totally or
partially closed by means of a sliding shutter fixed outside the lock plate which shutter
is retained in position by a spring or spring and catch so arranged that the shutter
can only be released by means of a properly constructed key in the hands of a person
acquainted with the manner of using the same, the apparatus being so constructed
that unless pressure be applied to the key at the precise moment required by the
pattern of the lock the key will continue to ride upon the upper flange of the barrel
outside the lock plate without penetrating into the interior of the lock. If however
the key be manipulated in such manner as to pass into the box of the lock the
difficulty of opening the same is increased by forming a male screw thread on the
guide pin or stud over which the barrel of the key passes and a corresponding female
thread in the barrel of the key. The screw may be either right or left hand and
consists of several turns so as to occupy some time before the wards of the key begin
to act on the tumblers or catches the lock.
The screw thread in the barrel of the key is concealed from sight by means of a
small piston which is kept in position by a spring so that there is nothing in the
appearance of the key to suggest that it differs from those of ordinary construction.
The combination of difficulties presented by locks constructed according to my
Invention will be sufficient to defeat any attempts to open the same except by
violence and it will be easy to construct the parts in such a manner that a person
partially acquainted with mode of operation and in possession of the proper key
would probably break or displace some essential working part in a fruitless attempt
to make use of the same.
And in order that my invention may be better understood, I have illustrated the same
in the accompanying drawing in which Fig. 1 is a plan of the lock and Fig. 2 a

page_text: sectional elevation of the same with the lock plate removed, Fig. 3 being a front
view of the bolt and catch.
Referring to fig. 1 L is the lock plate through which projects the barrel f of the
lock, the latter being provided with a central perforation for the entrance of the
key barrel, while the ward slot a formed in the lock plate to make it resemble an
ordinary lock is partly there by way of deception, as the key ward cannot wholly enter
the same, but after the key barrel has been pushed sufficiently far into the central
perforation of the barrel fit has to be turned to the right in order to raise or shift
the shutter e held in position by the spring d for the purpose of gaining access to
the interior of the lock box through the slot or true key hole a¹.
In fig. 2 A is the key which is shewn as having reached the interior of the lock
proper, after the spring k having been first compressed by means of the piston J,
both of which are placed within the said key barrel as shewn. The key A which is
furnished with a female screw thread h has also been screwed a few turns over the
male screw thread G formed on the guiding pin g of the lock, so that the ward of
the key assumes the position shewn at p ready to withdraw by a further turn the
catch or tumbler s from the notch formed in the bolt 1, the latter being thus finally
released. By a reverse but exactly similar manipulation, the key can be removed
from the said lock. The said lock is slipped within a recess formed in a door frame,
so that only the barrel fand the slot a is visible from the outside.
Having now particularly described and ascertained the nature and object of my
Invention and in what manner the same may be performed or put in practise. What
I claim is.
1. The general construction of a lock so arranged as to prevent same being
tampered with by skeleton keys or any person or persons unacquainted with the lock
although having the right key in their possession substantially as herein before
described.
2. The sliding shutters C for excluding the key way.
3. The piston in the barrel of key kept in position by a spiral spring so as to
exclude or cover the thread and depth of same.
Dated thi 15th of Mah 1000
HUGHES, ELI & HUGHES,
76, Chancery Lane, W.C.,
Agents for the Applicant.