IMPROVEMENTS IN BURGLAR ALARMS
Year: 1885

page_text: I, HERBERT JOHN ALLISON, of the firm of Allison Brothers, of 52 Chancery
Lane, London, in the County of Middlesex, Patent, Agents, do hereby declare the
nature of said invention for "IMPROVEMENTS IN BURGLAR ALARMS," a com-
munication to me from abroad by Alvah William Hall, Electrician, of 59 Liberty
Street, in the City and State of New York, United States of America, and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
In what are commonly known as electrical burglar alarm systems the object is
to give intimation by means of an audible or other signal at a given point of any
attempt to open a door or in any way to gain access to the structure or receptacle
which it is intended to protect against intrusion.
The applications of the system, while numberless, involve generally a circuit
between the structure or receptacle to be guarded and the place where the signal
is to be given, which circuit is broken or closed or otherwise affected by the act of
or attempt at intrusion, and so caused to sound the alarm. For example, the doors
and windows of a building are provided with circuit making or breaking devices,
so that any movement of them operates the said devices and gives an alarm in a
certain room in the building or at some distant station communicating by an
electric circuit with the building.
In the same way the doors of safes, the lids of boxes or chests and, in fine, all
kinds of receptacles are protected, so that unwarrantable intrusion cannot be
effected without sounding an alarm at some more or less remote point.
To this system, in all of the various applications above described, the present
invention is applicable, the main object of the same being to give instant warning
at any predetermined point, of the unauthorized entrance of or access to any
electrically protected building, safe or other receptacle, and to provide a means
whereby those authorized to open the doors of the protected structure, may do so
without sounding the alarm.
In carrying out my invention I make use of a double circuit or system of
circuits between the protected structure and the signal station, one portion of such
system being utilized, as is now done, for the transmission of signals, the other for
Die S21

page_text: controlling the first in such manner as to produce or prevent the signal which gives
intimation of the entrance to the protected structure; or any unauthorized tampering
with the devices, the manipulation of which is a necessary preliminary to such
entrance.
The signalling circuit and apparatus connected therewith may be generally
similar to any now used, that is to say, it comprises a battery, an alarm and some
device which is operated or brought into operation by a movement or displacement
of that portion of the protected structure to which it is, or may be applied.
The controlling circuit, on the other hand, contains suitably constructed and
applied apparatus to prevent the sounding of the alarm by the action of the devices
connected with the protected structure, and keys or contact makers at or in the
vicinity of the protected structure so arranged that by a proper inanipulation of
the same the signal is prevented, but by an improper manipulation the signal is
produced.
My object in this is that the proper manipulation of the aforesaid keys or contacts
may be a secret known only to the person or peisons authorized to open the
protected structure or receptacle so that anyone else either in attempting to
prevent the sounding of the alarm or to enter the structure, will at once set the
aların in action.
From the nature of the case, it is evident that, to afford adequate protection,
there must be a secret means of reaching or using the controlling circuit.
The number of such means is practically unlimited, but in describing more in
detail the nature of the invention, I shall describe only the specific means which
I employ in practice, and which I regard as the most practicable and efficient, and
which consist of a series of electrically controlled circuit closers similar in principle
to relays, which, together with the keys and circuit connections, form an electrically
controlled combination analogous in theory to those used in certain mechanical
locks.
2.
These devices, which, for convenience, will be herein designated "double circuit
instruments," are arranged in such manner that through the instrumentality of one
of the series the sounding of the alarm is prevented, whether by making or
breaking the alarm circuit, by shunting the current around the alarm magnets, or
by such similar action as the case may require. But such condition or operation
of the said instrument can only be maintained or effected by the previous operation
of one of the others, or by more than one in a predetermined order, and the keys
or contacts are connected with the several "double circuit instruments
so that
this may be done, but if the wrong key be depressed the combination is disarranged
and the aların is sounded. This combination of keys and circuit controlling.
instruments may be employed not only for sounding and preventing an alarm, but
for a great number of other useful purposes, and constitutes an important feature
of my invention.
:
In order to increase the utility of the system I employ what I term a key to be
used between the contact keys and the double circuit instruments for varying the
combination. A general description of this is that it consists of a certain number'
of contact surfaces connected by cross wires in different ways, so that when used
with the contact keys, the order of keys to be depressed to produce the proper
operation of the double circuit instruments will vary. By the use of these keys
the combination can be varied from time to time.
To further increase the efficiency of the system I construct the key in such
manner that it cannot be removed from the socket without sounding the alarm.
This is a matter of precaution to prevent any one from removing the key for the
purpose of discovering the combination by testing. To accomplish this, the circuit
or one branch of the same is carried through two portions of the socket that are
separated in the act of removing the key, or through the key itself, so that on
removing the same the circuit is interrupted and the alarm sounded.
This, while advisable in the case of simple keys, is rendered unnecessary by a
certain novel manner of making the keys which forms a part of my invention.
"

page_text: Fig. 7, is an edge view of the same.
Fig. 8, is a section of the key showing the arrangement of circuit connections.
Let H, represent a structure or receptacle to be protected, and provided with a
circuit breaker J, which may be of any ordinary description, and arranged to
interrupt the circuit with which it is used when the door of the structure is
moved.
From this circuit breaker run wires 10, 11, 13 to a station at which is located
an alarm, the electro magnet I, of which is in the circuit of which these wires
form a part. A galvanic battery J, is also connected with these wires and furnishes
the current that operates the magnet.
In Figure 1, the magnet controls a mechanical bell T, this being done by
connecting the armature of the magnet with a detent S, that engages with the
wheel W, when the magnet is active, and which is thrown out of gear when the
magnet is inactive.
At the alarm station are located a series of double circuit instruments A, B, C, D,
the number being an arbitrary one, as will hereinafter more fully appear. The
principle of these instruments is similar to that of an ordinary relay, except that
they have two magnets, one of which locks an armature in a position in which it
closes one or more circuits, and the other releases the said armature so that it
simply breaks the circuit or circuits, or closes others.
In Figures 3 and 4, the details of the instrument A, are illustrated.
Referring to said figures, a', designates one electro magnet; a³, is its armature
lever which connects by a rod a³, with a lever a, the lower end of which connects
with a rod a, which carries two roller studs aº, a7.
The letter a, designates another magnet the armature lever a of which serves to
lock the armature lever of the magnet a¹, whenever the latter, being rendered
active, moves or shifts its armature. The armature a², is held by the lever a³, until
magnet a, is energized; when the circuit of magnet a', is closed the roller stud aº,
closes the front contact spring h², while the back contact springs, h; remain off
their stops and this condition is maintained after the interruption of the circuit of
magnet a¹, and until the magnet a, is energized, when the armature lever a³, falls
back, the front contact spring leaves its stop, and the back contact springs h¹, h,
are brought into contact with their stops.
Instruments C, and D, differ from that described only in this respect, instru-
ment C, has a single back contact spring j, only, and the instrument D, has two
front contact springs k, l, only. Instrument B, is in all respects similar to that
designated A.
The magnets a, b, c, which may be regarded as the main magnets, are in a
branch 38, 39, 40, 41, 20, of the controlling circuit 28, that runs to some point
near the proteteel structure H. The main portion 28, of this circuit contains a
0

page_text: battery X, and is connected with the several branches that form the return circuit
by keys or contact makers. The key O, connects it with the branch 38, 39, 40, 41
and 20, which contains the magnets a, b, c, and this key is depressed so as to
energize the magnets and lock their armatures in order to set the apparatus or
bring into operative condition.
A branch 26, 27, 58 and 20 containing a key O¹, includes the magnet d', and is
to be closed at the outset or after the alarm has been sounded in order to set the
instrument D, and complete the signalling circuit through the wires 10, 11 and 12,
and spring l
In order to permit the door of the structure H, to be moved without sounding
the alarm, I place in the vicinity of the structure a certain number of keys or
contact makers K1, K2, etc. one of the points of each being connected with the
battery X, by wires 28, 48. From the other points or contacts run wires 30,
32, etc. back to the double circuit instruments and through the connections
of a combination key when so desired. A wire 17, runs from the wire 10, to the
first of the series of double circuit instruments. This wire forms a branch of the
circuit from battery J, around the circuit breaker J¹, and when in connection with
wire 12, the magnet I, remains energized when the circuit through wire 11 is
interrupted. The object in the present case then is to extend through the series of
double circuit instruments a path for the current between wires 17, and 12.
Assume that the connections be such that keys K³, K' and K³ must be depressed
in the order named to operate first the instrument A, then B, and finally, C, the
operation is as follows:-
Depressing key or contact K, closes the branch 30, 30, 20, which includes the
secondary or releasing magnet of instrument A. Normally the strip or spring h
of this instrument is in contact with its stop and springs h, h', out of contact with
their respective stops, but as soon as magnet, a, is energized this condition of things
is reversed. Wire 17, is connected to spring h, so that it is brought into connection
with a wire 14, leading to instrument B, and wire 32 of the branch including
key K, is connected by spring h¹, with wire 33. Key K, is then depressed; this
completes the circuit through the branch 32, 33, 34 and 20, energizes magnet b, of
instrument B, connects wires 17 and 14, with wire 25, through spring i, and
wire 35, from key K³, with wire 36. By depressing then key K³, the circuit is
completed through branch 35, 36, 37 and 20 and magnet c, of instrument C,
energized. This connects wire 25 with wire 16, which completes the circuit 12, 13,
10, 17, 14, 15 and 16, through spring k, of instrument D. A circuit through
magnet I, and around the circuit breaker J¹, being thus formed, the structure H,
may be opened without sounding the alarm bell T. When the building or
receptacle is closed the combination is set by depressing key O, which energizes
magnets a, b, c, and reverses the order of connections as above described.
If any other key than those designated K, K, K³, be depressed, in attempting
to operate the combination, or if these keys be depressed in the wrong order, the
result, will be the sounding of an aların; for instance, if after depressing key K³, a
key, as key K', be touched, instead of key K, the branch 29 and 20, including the
magnet d, of instrument D, is closed, the springs k, l, carried away from their stops,
the circuit of magnet I, broken, and the alarm sounded. So, if one of the keys, as
key K, be depressed out of its proper order, the branch 32, 29, and 20 is closed
through the spring h³, of instrument A, and the alarm sounded. These examples
serve as illustrations of the working of the system.
After the magnet d, has broken the alarm circuit, the circuit is closed again by
key O, that controls a circuit 26, 27, 58, 20, including the main magnet d'.
In order to provide for various combinations I employ what I term a key which
is placed in a socket, the key and socket being shown in detail in figures 5, 6, 7,
and 8. The key consists of a shallow receptacle A¹, filled with insulating material
and containing a given number of metal pins or blocks.
This fits down in a holder A2, in which are the same number of insulated metal
pins in corresponding positions,"

page_text: The pins or blocks in the part A¹, are connected across in various ways, so that
the double circuit instruments A, B, C, are connected with such of the keys K';
K, etc., as the particular key used may determine.
As the circuits through the wires 30, 32, 35 and 29, are normally open, it is
evident that the removal of the key A', from its socket would not affect the
instruments that make up the combination. Under such circumstances, therefore,
it would be possible for a person to remove the key for the purpose of discovering
the combination.
But this I guard against by running the main circuit through the key and
socket or through the parts that are necessarily separated by the act of removing
the key from the socket. I prefer to do this by attaching the main wire to
insulated contacts in the socket upon which rest two connected contacts, or one
large contact in the key.
This involves, of course, an alarm system in which a constantly closed circuit is
used, by the interruption of which the alarm is sounded. The principle is equally
applicable, however, as will be readily understood, to systems the converse of this,-
that is to say, in which a normally open circuit is used-for in that case the
removal of the key could be made to close the circuit.
This is shown in the system illustrated in figure 2. In said figure the arrange-
ment of circuits and electrical controlling mechanism is substantially the same as in
figure 1. A somewhat different form of alarm is used, however, which is illustrated
in a conventional manner. It has two electro magnets M, I, that control a
mechanical bell T; these are provided with armatures so arranged that when one
or both is active, the train that rings the bell is locked, but when both are inactive
the train is unlocked and the bell rung.
The main or alarm circuit 10, 11, 12, in this case, is carried through the socket
and key. So that if the key be removed from the socket the alarm,will be sounded,
as the magnet M, is normally inactive, and by making the circuit through the
magnet I, the bell train is released.
The key must be placed in the socket in a given manner in order to form the
combination; for this purpose each key may have a lug that fits into a corre-
sponding recess in the socket. This, however, affords an easy manner of discovering
the combination which any given key provides for by testing to ascertain which
contacts are connected, so as to operate, when the key is in place, the instruments
A, B, C, in the order named. To prevent this, however, I make the keys with a
number of such points as a lug or recess, distinguishing them in some way, so as to
make a knowledge of which.is the proper starting point a prerequisite to securing
the proper combination.
The special form of construction of key and socket for the same is as follows :—
The lock or holder consists of a metal casing A2 of any proper shape or design.
containing a plate B₁ of insulating material forming the bottom of socket for
receiving the key A¹. A plate C¹ hinged to the holder and is adapted to close
over the key when in place. Any suitable form of catch as B' is used for holding
the lid or plate C¹ down upon the key.
The insulating plate B2 contains a circular series of spring contacts D' which are
pins projecting up through the plate and held up by springs enclosed in chambers,
in the plate. A second plate E' is secured within the holder and carries a number
of binding posts E³ connected with the spring contacts D¹. In the centre of
contacts D¹ are two similar contacts also connected with binding posts on plate E¹.
The key consists of a shallow cup or receptacle A¹ containing in its periphery a
number of distinctive divisional marks such as notches n at equal distances apart.
The key is filled with a hard insulating substance in which are set a circular series.
of metal contact points F,. and a larger central point G. In the socket is a pro-,
jection b², and when the key is inserted in the socket with said projection entering.
que of the notches n the points F, and the terminal pins D', are all in contact and
the point G, is in contact with the two pins.

page_text: -
Suppose the notches to be numbered, lettered, or otherwise distinguished then
key with the connections shown in Fig. 8, when applied to the system illustrated
in Fig. 2 would form the combination 1, 5, 4, 3, that is to say when the key is
placed in the socket with the pin or projection 6, entering notch No 1 the circuit
must be closed through the fifth contact from the notch 1, then through the fourth
contact, and then through the third, in order to make the circuit to the contacts
with which instruments A, B, and C, are connected, in the order named. If the
circuit be closed through any other contacts or in any other order through the
proper contacts, the combination is broken and the alarm sounded as has been
previously explained.
To a person not in possession of the secret of the combination it will be seen
from the above that it would be a matter of great difficulty to discover the com-
bination, as he must ascertain not only the order of contacts, but the starting point
from which they are reckoned.
The key cannot be removed from the socket or holder without breaking the
circuit through the point F, and pins in contact therewith.
In the systems illustrated an independent magnet is used with each of the
instruments A, B, C, and D, for setting the armatures. In lieu of this I propose to
use one magnet for two or more armatures in any well understood manner, thus
bringing the instruments into more compact form.
It will be understood from the foregoing description that the number of figures
constituting a combination is practically unlimited. As an instance of one simple
arrangement, suppose a number of operating keys or contacts are used and only
one of the number is to be used for preventing the alarm, it would be necessary to
use only two double circuit instruments. The operating key bearing the figure
corresponding to that .selected as the combination would connect with the first
double circuit instrument and the circuits from all the other keys would run to the
second double circuit instrument. In order to open.the receptacle without sounding
the alarm, the proper key must be depressed; if any other key is depressed, the
alarm will be sounded. In the same manner, if it is desired to use two keys to
make the combination, three double circuit instruments would be used which should
be connected upon the same principle as described. By increasing the number of
keys and the number of double circuit instruments an unlimited number of com-
binations may be provided for.
It is obvious that the series of double circuit instruments may be employed for
controlling or sounding the alarm in a great variety of ways. Nor is the use of
these devices confined to this particular purpose alone, as it is evident that they
may be employed under many and various conditions for operating or controlling
the operation of other devices, whether electrical or mechanical, wherever the
ability to operate or control the operation of such devices involves a knowledge of
a prearranged manipulation of the intermediate mechanisins for bringing them into
the proper relations for obtaining the desired result. In all cases it will be
observed that the final instrument of the series, or that designated by the letter D,
while it performs no part directly in the control of the alarm, or other devices,
operates as a check on the improper manipulation of the devices composing the
combination.
As I have before stated, the device connected with the structure or receptacle to
be protected may be a simple circuit breaker or contact maker, or any instrument
that affects the electrical conditions of a circuit to a degree sufficient to operate an
alarm, either directly or indirectly.
. The exact point at which the double circuit instruments are connected into the
controlling circuit is evidently a matter determined by the conditions of particular
cases.
The specific details of construction of the apparatus used in carrying out my
invention may be modified and varied in a great many respects. The special
character of certain parts of the apparatus will depend upon the form of alarm

page_text: used. For example, I may use an alarm that is sounded by breaking the circuit
through one or more magnets or making the circuit through the same; and in
many other particulars the system may be varied and modified without departing
from the invention.
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
1st The combination with a structure or receptacle to be protected, and an alarm
or signal station of two electric circuits connecting the same, burglar alarm
mechanism in one of said circuits and electro magnetic mechanism in the other,
and means for operating the same arranged to control the operation of the alarm,
substantially as herein set forth.
2nd The combination with a structure or receptacle to be protected and a signal
station of two electric circuits connecting the same, of burglar alarm mechanism
included in one circuit, a series of co-operating electro magnetic instruments and
means for operating the same connected with the other circuit and arranged to
control the operation of the alarm mechanism substantially as herein set forth.
3rd The combination with a structure or receptacle to be protected and a signal
or alarm station, of two electric circuits connecting the same, of burglar alarm
mechanism in one circuit, a series of electro magnetic circuit closers and keys or
contact makers in branches of the other circuit, for controlling the alarm circuit,
and electrical connections so formed that a predetermined order of operation of the
circuit closers is necessary to prevent the sounding of the alarm, as and for the
purpose specified.
4th The combination with a structure or receptacle to be protected and a signal
or alarm station, of two electric circuits connecting the same, burglar aların
mechanism in one circuit, a series of double circuit instruments and keys or contact
makers for operating the same included in branches of the other circuit, and
electrical connections to one of said instruments so arranged that its operation sets
the alarmn in action, and to the other instrument or instruments so arranged that
the proper operation of the same prevents the alarm from sounding as and for the
purpose specified.
5th The combination with an electrically operated mechanism, of a series of
double circuit instruments for controlling the same, the said instruments being
electrically connected in such manner that they must be successively operated in
a given order to secure the control of the said mechanism, substantially as herein
described.
6th The combination with an electrically operated mechanism of a series of
double circuit instruments for controlling the same, electrically connected to form
a combination or a system in which the several instruments must be operated
successively in a given order to secure the control of the said mechanism and a
double circuit instrument electrically connected with the controlling instruments in
such manner that the operation of the latter out of a given order disarranges the
combination, as and for the purpose set forth.
7th The combination with an electrically controlled mechanism in one circuit and
a series of double circuit instruments and keys or contact makers adapted to control
the said mechanism and included in branches of a second circuit and electrical con-
nections through the instruments so arranged that the said instruments must be
successively operated in a given order to secure the control of the said mechanism
as and for the purpose set forth.
8th The combination with an electric circuit divided into a number of parts or
branches, of a series of co-operating electro magnetic instruments connected with
a portion of said branches, circuit connections between the instruments forming an
electrically operated combination, keys or contact makers included in other branches
of the circuit, and combination keys for connecting in different orders the branches
containing the keys with those containing the instruments operated by the same,,
as and for the purpose set forth.
.

page_text: 1
9th The combination with the alarm circuit and an electro magnetic alarm
connected therewith, of a second or controlling circuit, a series of double circuit
instruments connected with branches of the same and arranged to control the alarm
circuit, operating keys or contact makers in branches of the circuit connected with
the secondary or releasing magnets of the double circuit instruments and a restoring
or setting key in a branch of the circuit including the main magnets of all the
instruments, as and for the purpose set forth.
10th The combination key herein described consisting of a metal bolder. filled
with insulating material, contact points or plates embedded in the material, a
portion of the plates being connected together in pairs and the rest in a group of
three or more, as set forth.
11th The combination with the key containing a number of contact plates
connected together partly in pairs and the rest in a group, of a socket or lock for
the same containing contact plates, corresponding in number and position with
those in the key as set forth.
12th A burglar alarm system comprising the following elements combined and
arranged in the manner specified, a structure to be protected containing a circuit
breaker or equivalent, a signal or alarm station containing an electro magnetic
alarm operated by the movement of the part of the structure to be protected with
which the circuit breaker is connected, a second or controlling circuit, keys or con-
tacts located in the vicinity of the structure to be guarded and included in branches
of the controlling circuit, a series of double circuit instruments at the signal station
in branches of the controlling circuit connected with those containing the keys,
electrical connections between said instruments, a branch of the alarm circuit con-
trolled by the instruments for preventing or sounding the alarm and branches of
the controlling circuit containing keys for restoring or resetting the double circuit
instruments after they have been operated.
13th The combination with a structure to be protected, and a signal or alarm
station, of an alarm circuit and a controlling circuit connecting the same, burglar
alarm mechanism in the alarm circuit, a series of double circuit instruments and
keys or contact makers included in branches of the controlling circuit for controlling
the alarm, a socket or holder and detachable key for varying the connections
between the contact makers and the double circuit instruments, the said socket
containing a metallic path for the alarm circuit that is interrupted by the removal
of the key, as and for the purpose set forth.
14th The combination with a structure to be protected and a signal or alarm
station, of an alarm circuit and a controlling circuit connecting the same, burglar
alarm mechanism in the alarm circuit, a series of double circuit instruments, and
keys or contact makers included in branches of the controlling circuit for con-
trolling the alarm, a socket or holder and a detachable key for varying the
connections between the contact makers and the double circuit instruments, the
said socket containing contacts to which the alarm circuit wire is. connected and
the key being provided with a metal point or points for bridging said contacts
whereby the alarm circuit is broken by the removal of the key, as and for the
purpose set forth..
15th In a burglar alarm system of the kind described, the combination with
a socket or holder containing insulated contact points connected with the branches
of the controlling circuit, of a combination key for connecting said contact points
in a given order, the said key being formed with a number of connected contact
points arranged about a centre and having distinctive divisional marks for
indicating its position in the socket for making the proper connections, as and for
the purpose set forth.
16th In a burglar alarm system of the kind described the combination with
a socket or holder containing insulated contact points connected with the branches
of the controlling circuit and provided with a point or projection extending into
the space containing the contacts, of a combination key for connecting the contact
points when inserted in the socket, consisting of a receptacle filled with insulating

page_text: material and containing connected contact points, the periphery of the key having
a number of notches into one of which the projection in the socket extends when
the key is in place, the notches being numbered or otherwise distinguished whereby
the proper position of the key in the socket may be determined, as and for the
purpose set forth.
17th In a burglar alarm system of the kind described, the combination with
a socket containing insulated spring contacts connected with the branches of the
controlling circuit, of a key provided with corresponding insulated contacts con-
nected in a given order and adapted to connect the contacts of the socket when the
key is inserted therein, and a locking device for holding said key in place, sub-
stantially as herein set forth.
18th The socket consisting of a metal case containing an insulating plate in which
are set spring contacts, and a plate carrying binding posts or terminals connected
with the contacts in combination with a key consisting of a metal receptacle filled
with insulating material and containing contacts corresponding with those in the
socket and connected in a given order, a hinged lid or plate and a locking device
for locking the key in the socket, all as set forth.
19th The combination with two or more electro magnets and armatures and
circuit directors operated or controlled thereby in the manner described, of an
electro magnet and armature and a device under control of the armature for
bringing the circuit directors in engagement with their respective controlling
armatures, as and for the purpose set forth.
D
1