Improvements in Fire Alarms.
Year: 1889

page_text: Date of Application, 3rd Dec., 1889-Accepted, 15th Mar.,
1890
COMPLETE SPECIFICATION.
Improvements in Fire Alarms.
I, JOHN PATRICK MCMAHON, of 309 South Division Street, in the City of Buffalo,
in the County of Erie and State of New York, United States of America, Electrician,
do hereby declare the nature of my Invention for AUXILIARY FIRE ALARMS, and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My Invention is embodied in the novel arrangement and construction of the
circuits and apparatus for the transmission automatically of signals from a building
or group of buildings to be protected, to a central office, and for the reception and
recording of said signals at the central office, all as hereinafter described and
claimed.
The object of the Invention is to provide simple and reliable means whereby an
alarm will be given upon the breaking out of a fire in a building, both at the point
where a fire occurs and at some distant point; to indicate the exact location of the
fire by visual and audible signals at both points; to insure these things being done
whether the line connecting the building or group of buildings with the central
office is broken, grounded or short circuited, and whether the wires in the building
are broken, grounded or otherwise interrupted; to distinguish between fire alarms
and those caused by derangement of the wires and prevent false alarms; and to secure
other advantages hereinafter referred to.
The improved system consists mainly of the following parts:
First: A suitable battery, which is included in a normally closed metallic circuit,
and with which is combined a normally open grounded circuit on the same wire.
Second: A relay, or other usual and suitable receiving instrument on each circuit,
for receiving and recording signals.
Third: A signal box and indicator, located at the building to be protected.
Fourth-Thermostatic circuit controllers.
Fifth-The system of wires connecting the thermostats with the signal box, and
with a central office.
The battery used is preferably a gravity battery, and is included in a closed
metallic circuit. Said circuit includes a relay or other suitable device for receiving
signals, and a key for interrupting the circuit. At the centre of the battery a
wire is attached. This wire is connected to another relay from which a wire leads to
the lever of a button switch, one contact of said switch being in connection with the
earth.
The signal box and indicator comprise a transmitting instrument consisting of a
motor or clock train controlled by electro magnets; a number of story magnets
which control the movement of a pointer for indicating the different stories or sections
of a building, and accomplish certain other results; and a break wheel and circuit
breakers which are adapted to break the electric circuit and transmit a signal, the
character of which is determined by the number of times the circuit is broken.
The motor employed consists of a train of gear wheels, operated by a spring.
The second and fourth wheels have pins inserted in them which engage with the free
end of a lever, the other end of which is connected with the armature of the
controlling magnets. When the controlling magnets are energized the armature
is attracted and depresses the outer end of the pivoted lever, freeing it from its
engagement with the second wheel of the motor and allowing it to rotate. Should
the lever be depressed for a sufficient length of time to allow the fourth or slow-
going wheel to make a complete revolution, the lever would engage with the pin
on the face of said wheel and cause the motor to stop. The controlling magnets are
included in a normally open circuit that is completed and closed by the action of the
story magnets, on their being energized.

page_text: The box also contains two small relays and a small switch, the objects of which
will be shown hereafter.
The break wheel is mounted on the shaft of the second wheel of the motor, as
is also a short arm, the use of which will be described later on. The circuit breakers
consist of a number of spring-contact pieces or brushes mounted upon suitable
insulation, and resting against a number of contact points that project through
the insulation, and serve to either break or complete the circuit, according as they
may be in or out of contact with each other. The break wheel consists of metal
disks having upon their edges a number of projections, so arranged as to lift the
contact pieces or brushes and break the circuit a definite number of times. These
disks are insulated from each other and from the shaft upon which they are mounted.
The story magnets are mounted upon the face plate of the box in such manner
that when their armatures are attracted they will cause a rod, which is attached to the
free end of the armature, to project through the face plate and engage a pointer that
is carried on the shaft of the motor in much the same manner as is the minute hand
of a clock.
The arm on the shaft of the break wheel engages the lever of the small switch
when the motor rotates the wheel, breaks the short circuit established by the story
magnet, and places the lever in connection with a contact point, to which a wire
leading to the open contact thermostats is attached, and which completes the grounded
circuit when a thermostat is operated. A bell is also included in this wire for the
purpose of alarming the occupants of the building in case of fire.
The thermostatic circuit controllers and the system of wiring will be referred to
further herein.
In the drawings,
Fig. 1 is a diagrammatic view of the system as a whole, showing the manner of
wiring and connecting the various parts.
Fig. 2 is a partly sectional view of the signal box showing one of the story magnets
in its relation to the break wheel and pointer.
Fig. 3 is a face view of the signal box, parts within the box being shown in dotted
lines.
Fig. 4 is an edge view of the motor.
Fig. 5 is a sectional view of the same on the line y-y of Fig. 4, parts being
broken away.
Figs. 6, 7, 8, 9 and 10 are detail views of the break wheel.
Figs. 11 and 12 are detail views of the circuit breaker.
Fig. 13 is a detail view of the circuit breaker in its relation to the break wheel.
Fig. 14 is a plan view of the double thermostat employed.
Fig. 15 is a similar view of the same with part of the casing removed, and
Figs. 16 and 17 are vertical sectional views of the same on planes substantially at
right angles one to the other.
The battery MB, which is the only battery employed in my system, is located
at the central office. It is in a closed metallic circuit formed by a continuous
wire from the battery to and through the building or buildings to be protected and
the closed contact thermostats therein, and back again to the battery. With this
closed metallic circuit is combined on the same wire an open ground circuit which
is completed by the action of some one of the open contact thermostats as will be
explained hereafter. To provide for one ground for this open ground circuit a wire
or branch 26 is run from the centre of the battery in the central office to the
ground. For convenience and for the purpose of testing, this branch is run through
a two point switch GS, so that by turning the switch button the earth connection can
be made or broken at will. The switch is normally closed, thus grounding the battery
in the middle.
The thermostats or heat detectors are instruments which will cause a signal to be
transmitted to the central office whenever the temperature of the room in which they
are located exceeds the point at which they are set. They may be of any ordinary
construction, and, as indicated above, are of two classes, those of the one class

page_text: operating to open the metallic circuit, and those of the other class to close the open
ground circuit, thus sending two distinct signals. It is evident that these two forms
might be combined in one, and I have shown a desirable form of such a double
thermostat in Figs. 14, 15, 16 and 17. Upon a suitable insulated base four spring
metal strips are mounted. Strips 1× and 2× are connected to binding posts, to
which are attached the terminals of the main building circuit (wire 2, Fig. 1).
Strips 1× and 2× are represented in Fig. 16 as slightly separated for the sake of
clearness, but are in electrical contact, when the instrument is in its normal condition
(that is when closed ready to send a fire alarm). They complete the main metallic
circuit from B¹x to B**, and are held in contact with each other by the insulated
post P. The strips 3x and 4* are connected to binding posts B³× and B**, of
which B³× is attached to a wire leading to earth (wire 25, Fig. 1). B** is attached
to a wire which leads to signal box and is there connected as shown in Fig. 1
(wire 5). These strips are kept apart by the post P when the thermostat is closed.
It will be seen that the post is reduced in diameter near the inner end to form a
shoulder, and that the reduced portion is passed through a hole in the strip 4* in
order that the extremity of the post may rest against the strip 2*, while the shoulder
rests against the strip 4*. The springs are enclosed in a stout metal case O, through
which projects a tube T which is screwed into the case, and whose outer or exposed
end is sealed by a thin disk of brass D, which is soldered to the body of the tube
with solder which fuses at a degree of temperature previously determined. The post P
rests upon this disk, and on the tube being screwed into position forces the springs 1×
and 2× together, thus closing the metallic circuit through the thermostat, and at the
same tim separating springs 3* and *: holding them apart (thus breaking the
contact between wire 5 and wire 25, Fig. 1). Should a fire occur near one of
the thermostats the temperature would be raised above the fusing point of the solder,
which is preferably about 160° Fahrenheit, and the disk would be freed from the
tube; post P would be released. springs 3x and 4× would form a connection and
springs 1× and 2× would separate. Wire 2 would be interrupted, wire 5 would be
connected to earth and a fire signal would be transmitted to the central office by the
signal box located in the building.
The receiving instruments at the central office may consist of a relay R', on the
metallic circuit with a register and a bell, and a relay R2, included in the ground
branch from the battery with a register and a bell. An extra bell is also used on the
local circuit of the relay R².
The relay used in the closed circuit may be of a standard pattern, and preferably
is so arranged that when the circuit is broken the armature will be released and will
close a local circuit which includes the register b and bell d. This closing of the local
circuit will cause the register to start and make a mark on a paper tape corresponding
to the length of time the local circuit is closed. On the main circuit being closed,
the relay armature will be attracted, the local circuit broken, and the register stopped.
In like manner each time the local circuit is closed one stroke is given on the bell. The
instruments on the ground circuit preferably differ from those just referred to in this
respect: The relay has contact points which close the local circuit when the armature
is either open or closed, but the circuit from the back contact of the relay is
broken by a small switch LS. The back contact of the relay is in circuit with the
register and bell d¹, and the front contact with the extra belld which latter is of
the class known as vibrating bells. These receiving instruments are of ordinary
construction and arrangement, and form no part of my Invention. Hence they are
not described or shown more in detail.
It will be evident that if a ground occur on the line, either by the action of one
of the open contact thermostats or from an accidental ground, the armature of relay R³
would be attracted and close the local circuit, and give an audible signal upon a bell,
which would cause the attention of the operator to the fact that the circuit had been
grounded outside of the central office. Should this signal be received without a
previous signal on the metallic circuit instrument it would indicate a foreign ground,
that is, one caused by accident to the line wire; all that would be necessary to do to

page_text: clear the line for the reception of signals on the metallic circuit would be to open the
ground connection in the central office by means of the switch GS. Signals would
then be received on the metallic circuit instrument R', from any building on the line,
until the foreign ground was located and removed. Should a thermostat close the
ground circuit it would close it through both halves of the battery, and on the right and
left legs of the circuit, but as the signal box, by means hereinafter described, breaks
the circuit on both sides of the thermostat ground, the relay R2 responds freely to
each break caused by the circuit breaker of the signal box, and the same signal is
received as that received on the metallic circuit instrument R¹. Should a break occur
on the main line the buildings are still protected, for as soon as the thermostat operates,
it closes the ground circuit through the battery and the line to the central office on
which it may be connected. This would start the signal box and a signal would be
received on the relay R2, showing that a thermostat had opened at the building
indicated. It will also be seen that every time the main circuit is broken by the
rotation of the break wheel of the signal box, as hereinafter described, the relay.
armatures are released and the local circuit is closed., Upon the main circuit closing,
the armatures are again attracted and the local circuit is broken and a signal is
received corresponding to the number of times the main circuit is broken and closed
by the signal box. The local circuit of the register on the ground circuit is normally
opened at the small switch mentioned above, and the circuit is through the vibrating
bell. On a ground being thrown on the line the armature of relay R² is attracted
and closes the local circuit through the vibrating bell, which rings continuously until
shut off by the operator at the central office. This is done by moving the. small
switch LS and in doing this the circuit to the register is completed for the reception
of signals.
The signal box and indicator is an instrument which is placed at the building to be
protected. It contains: a clock train Z run by a spring; a break wheel W carried
on the shaft of one of the wheels of the train; a circuit breaker A of as many
members as may be required by the size of the building; two magnets M¹ M², to
release and control the movement of the clock train, and a number of magnets M³,
M4, M5 to indicate the stories or floors on which the fire may occur; and two small
relays R³, R. The shaft of the break wheel carries a short arm H which engages
the lever L of a small switch S and shifts it from one contact point P¹ to another P2
when the wheel makes a rotation. The construction, arrangement and operation of
these parts will be explained in detail hereafter.
The wiring of the buildings, necessary to connect the thermostats with each other
and with the signal box and indicator, is done in the following manner: The left
hand leg of the circuit, (wire 1, Fig. 1) is brought to binding post B¹ of box, where
it connects with wires and other appliances and connects with binding post B2; from
there wire 2 (Fig. 1), is run to all the floors of the building, and is carried through
every room on the floor at the ceiling. At proper intervals the wire is cut and
connected to thermostats, which when closed complete it. After being carried through
all the various floors and rooms of the building it is carried back to the box, which it
enters at B³ and is again connected by a system of brushes and wires with the
right hand leg of the circuit (wire 4, Fig. 1), thus making a complete circuit of the
building. This wire is the main building circuit. There are also two others, wire 5
and wire 25. Wire 5 is carried from the box to every open contact thermostat in the
building, and is stripped of its insulation and inserted in a binding post as shown in
Fig. 17. It is thus in metallic connection with spring 4× (Fig. 17) of every open
contact thermostat and ready to make connection with the earth on a thermostat
being operated. In order that this wire may not be disabled by a break, it is carried
back to the signal box after making a complete circuit of the building, thus giving
two routes to the current in case of a break on this wire. It also affords an easy
method for the inspector to test the condition of this wire from the box without going
through the entire building. Wire 25 (Fig. 1), is also run through the building and
is connected to spring 3× (Fig. 17) of every open contact thermostat. It is connected
to earth at each end, and at as many intermediate points as may be convenient. This

page_text: is done in order that there may be no failure to work because of an accidental break
in the wire. I have indicated but three double thermostats T1, T2, T3, one for each
floor, but it is to be understood that each one of these represents a group located
on a floor or in a room.
The devices thus far described provide for the attainment of a portion only of the
objects of the invention.
In order to guard against derangement of the system which
might render it inoperative, to indicate exactly the location of a fire, to distinguish
between trouble alarms and fire alarins, to prevent false alarms, &c., &c., certain
details of construction and arrangement are necessary and will now be described.
The circuit breaker A consists of a number of spring contact pieces or brushes, A³,
A2, A3, A, A, mounted upon suitable insulation in the signal box, and resting against
a number of contact points C¹, 02, 03, 04, 0³, that project above the insulation.
These brushes and points serve to break or complete the circuit, according as they may
be in or out of contact. The spring contact pieces are raised out of contact with the "
points by projections on the break wheel.
Referring now to Fig. 1 it will be seen that the movements and actions of the
electric currents are as follows: Starting at the + pole of the battery, MB, the
current follows wire 1, key K, passes through the coils of relay R', by wire 1' to binding
post B¹, wire 1" to brush A of circuit breaker A, to contact C, wire 2¹ to coils of
relay R3; by 211 to binding post B², to wire 2, which is carried through all the rooms
of the building, through the thermostats and by wire 2 to binding post B³, wire 3
to coils of relay R, by wire 3' to contact 02 of breaker A, brush A², wire 4, to binding
post B, and by wire 4' to another building or back to pole of battery MB. This
completes the main metallic circuit.
-
Should a thermostat be operated, say T¹ on the first floor, the circuit would be
broken, and to obviate this and at the same time indicate which story the thermostat
has opened on, extra wires known as taps are connected to wire 2 where it enters the
floor, and are led to the signal box and back again to wire 2, where it enters the floor
next above. This with the magnet in the signal box forms a shunt around the break
and maintains the circuit intact, while it causes the signal box to transmit a signal to
central office. This is done as follows: At the point where wire 2¹ leaves contact ("
of breaker A, wire 6 is attached, which leads to the coils of magnet M¹, which controls
the mechanism of the box, by wire 61, wire 7, lever L of switch S, contact P¹, wire 7',
wire 23 to an insulated contact point D³, which is mounted on the frame of magnet M³.
The armature G³ of magnet M³ being attracted by the current through its coils
touches D³, and as it is connected with wire 8 by a short wire (24) it completes a
short circuit through the coils of the starting magnet M¹ from the contact C to the
outgoing main line at B4, thus energizing M¹ and attracting its armature, which
releases the clock train and causes the break wheel W to rotate in the direction shown
by the arrow. This break wheel consists of a number of metal disks corresponding
with the number of stories of the building in which it is located, in addition to
two disks for the main circuit. They are separated from each other and from the
shaft on which they are mounted by suitable insulating material. The outer disks W¹
and W2 (Figs. 6 and 10) have projections upon their edges as shown. These
projections are so arranged as to form, for example, the number 32, which is
repeated. Disks W³, W and W, Figs. 7, 8, 9 and 10, have respectively 1, 2 and 3
such projections, and are so arranged that a space is left between them and
the projections on disks 1 and 2. The break wheel W in rotating engages the
brushes of the circuit breaker A and lifts them off the contact points, thus
breaking the main circuit and causing a signal to be sent to the central office
The signal sent would in this instance be 32, 32-1, for the reason that as the break
occurs on the first floor the circuit is as follows:
Starting at the pole of MB, the current passes by wire 1, key K, relay R¹,
wire 1', post B¹, wire 1", brush A' of breaker A, contact C; wire 2¹, relay R³,
wire 2¹¹, post B², wire 2. As the wire is broken at T¹ the course of the
current would be by wire 11, post B10, wire 20, contact C³, brush A³, wire 19,
magnet. M³, wire 19, post B, wire 12, to wire. 2, where it enters second story, and by

page_text: ;
wire 2, wire 2¹¹¹, post B³, wire 3, relay R*, wire 3¹, contact C², brush A³, wire 4,
post B and wire 4' to battery MB. As the wheel W in rotating lifts the brushes A
from contacts C the circuit is broken. As current is on the shunt, which includes
brush A³, magnet M³ and contact 0³, the circuit will be broken when the projection
on disk W³ passes brush A³, and as but one projection is on this disk but one signal
is sent. Owing to the high resistance of the shunts, no current passes over them
while the main circuit is intact, and while the brushes of all the story shunts are
lifted by the wheel W, yet as current is only on the first floor shunt
signal is sent
from that floor only. As current is always on brushes A¹ and A2, a signal is sent
whenever a projection on W passes the brushes; thus as stated the signal received at
the central office would be 32-32-1.
This would indicate that the main line had been broken on the first floor of the
building in which box 32 was located. But as this signal might be caused by the
accidental breaking of the line as well as by the action of the thermostat when
operated by heat, it is necessary to provide means for distinguishing between a
signal caused by a break and one caused by a thermostat. By referring to Fig. 1
the manner in which this is done can be seen. The mechanism of the signal box is
held in check by a lever f, Fig. 5, which is connected by a rod e to the armature of
magnets M², M². This lever is held engaged with a pin p in one of the wheels r¹, of
the clock train, and prevents the break wheel from rotating until it is drawn away by
magnet M¹. When the circuit of M¹ is broken its armature is released and the lever,
through the action of a spring f1, again engages the wheel r, stopping the movement.
The line having been broken on the first floor, the armature of magnet M³
completes the circuit of magnet M', releases the box movement and starts wheel W
rotating the shaft of wheel W carries a short arm H, as will be seen by referring to
Figs. 1, 2 and 3, which arm in passing engages the lever L of switch S (Fig. 1), and
moves it from contact P¹ to contact P2, thus breaking the circuit of magnet M³,
releasing its armature and stopping the movement on the completion of one
revolution. The magnet M' is now in electrical contact with wire 5 through lever L
of switch S and contact P. If the break was caused by an accident to wire 2 no further
revolution of the wheel W takes place, and the signal sent is understood to indicate
a break on the first floor of 32. If on the contrary, the thermostat has been
operated by undue heat, wire 5 is thrown into contact with wire 25, and so with the
earth, and completes the open ground circuit from the ground and switch GS in the
central office through relay R², key K', wire 26, half of MB, wire 1, key K, relay R¹,
wire 1, post B, wire 1", brush A', contact C₁, wire 2', wire 6, magnet M¹, wire 61,
wire 7, lever L of switch S, contact P2, wire 5, bell J, wire 5, post B³, wire 5,
spring 4 of thermostat T¹, spring 3×, wire 25, to earth. The thermostat having
completed the open ground circuit the armature of relay R2 is attracted, and a bell is
rung in the central office; the operator throws the local switch LS, already referred
to, which connects the register with R'. As it has been thought unsafe to rely on
only one round of signals from the box, the movement is so arranged that the
armature of M¹, being held attracted by the current of the ground circuit passing
through its coils as explained, the lever f, Fig. 5, which is connected to the armature n
and which works on a pivot, engages a second wheel of the clock train. This wheel
is a slow-going one, and only makes one revolution, while the wheel, on whose shaft
the break wheel W is mounted, makes four. Thus three additional rounds of signals
are received before the slow wheel is engaged by the lever of armature n and the
movement stopped. As the brushes A' and A² break the circuit on both sides of the
ground at T', the relay R² responds freely to each break, and the same signal is
received as upon R'. Thus it will be seen that four rounds of the box will be
received upon two different instruments in case of fire, and only one round received
upon one instrument in case of a break.
Automatic fire alarm systems are liable to accidents, and the best system is that one
which is least liable to be rendered inoperative by an accident. That the possibility
of being rendered inoperative by an accident to any of its parts. is reduced to a
minimum in this system can be shown. If the metallic circuit be broken the open

page_text: ground circuit is still intact and ready to transmit a fire signal. Should the circuit
be grounded, by throwing the switch GS in the central office to the left, the circuit
is cleared for the reception of signals on the metallic circuit, and should a fire occur
in any of the buildings while the foreign ground was still on the circuit, a distinct
signal for fire would still be received, for the thermostat would complete the circuit
from the foreign ground through the coils of magnet M¹, and four rounds of the box
be received on R¹, instead of one round, which would be the case if caused by a break
in the building wire.
In case of a break in the main line the buildings would be still protected, as the
thermostat on being operated by heat would close the ground circuit through the coils
of either magnet M¹ or magnet M².
Suppose the break occurred on the left leg of the circuit or wire 1; the relays R³
and R would be demagnetized and their armatures would fall away from the cores
and rest against the stops F1 and F2. These stops are connected as follows: Stop Fl
with wire 10, which connects with wire 5 at B³, (Fig. 1); the armature of relay R³
is connected with magnet M² by wire 9', and wire 9 connects magnet M² with wire 3¹.
Should the thermostat complete the circuit, the course of the current would be as
follows: ground and switch GS, wire 25, relay R2, key K', half of MB, wire 4¹,
post B4, wire 4, brush A2, contact C³, wire 3¹, wire 9, magnet M², wire 9¹, armature
of relay R³, stop F¹, wire 10, post B³, wire 5, spring 4* of thermostat T¹, spring 3×
of the same, wire 25 to earth. The armature of M2, which is the same one acted
on by M', would be attracted and four rounds of the box be received on relay R² at
the central office. Should the break occur on the right leg or wire 4¹, the course of
the current would be reversed. In that event the circuit would be; ground and
switch GS, wire 26, relay R², key K¹, wire 26, the left half of battery MB, wire 1,
key K, relay R', wire 1', post B₁, wire 1", brush A¹, contact C¹, wire 2¹, wire 6,
magnet M', wire 61, stop F2, armature of relay R*, wire 27, post B6, wire 5¹,
spring 4 of thermostat T₁, spring 3*, wire 25, to earth, as before.
Should a line wire break in the building, thermostats on the floor where the break
occurred would be operative on the ground circuit, and all others would be operative
on both circuits. One round of the box would be received at the central office and
the floor signal would indicate the locality of the break.
As the thermostats are connected by a continuous wire from signal box through
the building back again to box, a break would not disable that wire, as there would
still be one route open for the passage of current; so with the ground wire, which
extends all through the building and is grounded at both ends.
Any other accident occurring would be indicated at the central office by special
signals, as for instance, a break on main line would release the armature of R'; this
would close the local circuit on its register and cause a long continuous mark to be
printed on its tape. So if a ground occurred on the main line, relay R2, would be
energized and its armature attracted, which would close the local circuit of the
vibrating bell and cause it to ring continuously until shut off by the operator at the
central office.
Should a building be short circuited and a fire occur in it, the thermostat would
ground the circuit, relay R2 would close and start the bell, and on pressing a key K,.
Fig. 1, a fire alarm would be received the same as if main line were broken.
It will be understood that it will be the duty of the operator, whenever a ground.
eignal is received, to open his key, leaving it open for a short time before moving
switch GS to clear the circuit..
The story magnets also serve as a local indicator, showing the floor on which the
fire occurs at the building where the box is located, as well as at the central office.
Figs. 2 and 3 show its construction.
The magnet is mounted on the face plate of the box and when its armature is
attracted causes the rod S2, which is attached to the free end of the armature, to
project beyond the plate; the outer end of this rod has a shoulder projecting which
engages a pointer x, Fig. 3, that is carried on the shaft of wheel W. This pointer
is fastened to the shaft in the same manner that, the minute hand. of a clock is, and ..

page_text: travels with the shaft until the projecting rod S2 is met, when its further progress is
stopped and it indicates the story by a number which is painted on the face plate at
the point where the hand has been stopped.
A bell J is included in wire 5, as shown in Fig. 1. When the ground circuit is
completed by a thermostat, the magnets of this bell are energized and it responds
to each break of the circuit caused by the wheel W passing the brushes of the circuit
breaker A. The bell can also be rung by breaking the circuit at the central office by
depressing key K¹, and be rung as long as desired, thus warning the occupants of the
building that a fire has occurred. Bells can also be placed at as many points as may
be desired in the building and included in this wire. This bell J will ring only when
the ground circuit has been completed by a thermostat.
Having thus described the working and construction of the various parts it will
be seen that the system cannot be disabled by any of the ordinary accidents to which
wire systems are subject.
It combines all the advantages of both open and closed circuits, metallic and ground.
All of its parts are under constant test. An accident is at once made known at
the central office; the machinery used is simple and effective.
The batteries are all massed in one place, thus lessening the cost of maintenance,
as well as affording means for close supervision.
No local batteries are used, thus doing away with an endless amount of trouble and
expense, as well as the risk of failure to operate at critical moments.
The system is always ready to work, and it is reliable, its parts being as few and
simple as possible.
It will distinguish between an alarm caused by trouble and a fire alarm.
.It will indicate the exact location of the fire.
The thermostats described are reliable and easily repaired. In case of having been
used, all that is necessary is to unscrew the tube and replace it with another, and as
the electrical contacts are inclosed in a dust proof case and protected from injury,
trouble from that source is obviated.
The sensitive solder which fastens the disk to the tube can be made to fuse at any
desired degree of temperature, although 160° Fahrenheit has been found to be most
suitable for the greatest number of buildings, still cases occur where higher temperatures
exist and the fusing point of the thermostat must be increased to correspond.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1-The combination of a closed metallic circuit including a thermostat, a motor,
a controlling magnet for said motor, a tap wire from said circuit on one side of said
thermostat and returning to said circuit on the other side of said thermostat
and including a magnet, contact points carried by said magnet and its armature,
electrical connections from said contact points to said controlling magnet, a ground
branch from said circuit, and a second ground branch including a thermostat,
whereby said controlling magnet may be further energized, as and for the purpose
described.
2:-The combination of a closed metallic circuit including a thermostat, a motor,
a controlling magnet for said motor, a tap wire from said circuit on one side of said
thermostat and returning to said circuit on the other side of said thermostat and
including a magnet, contact points carried by said magnet and its armature, a branch
from one leg of said circuit to said controlling magnet and to one of said contact
points, and a second branch from the other leg of said circuit to the other of said
contact points, a ground branch from said circuit and a second ground branch
including a thermostat, whereby said controlling magnet may be further energized, as
and for the purpose described.
3-The combination of a normally closed metallic circuit, a battery and thermostat
therein, a ground branch from said battery, a motor, a controlling magnet for said
motor, a tap wire from said. circuit on one side. of said. thermostat and returning to

page_text: said circuit on the other side of said thermostat and including a magnet, contact points
carried by said magnet and its armature, electrical connections from said contact.
points to said controlling magnet, and a second ground branch from the metallic
circuit including a thermostat, whereby said controlling magnet may be further
energized; as and for the purpose described.
4 The combination of a closed metallic circuit including a thermostat and a
characteristic circuit breaker, a second characteristic circuit breaker insulated from the
first, a motor for said circuit breakers, a controlling magnet, a tap wire from said circuit
on one side of said thermostat and returning to said. circuit on the other side of said
thermostat and including a magnet and said second circuit breaker, contact points
carried by said magnet and its armature, a branch from one leg of said circuit to
said controlling magnet, and to one of said contact points and a second branch from
the other leg of said circuit to the other of said contact points, as and for the
purpose described.
5: The combination of a closed metallic circuit including a thermostat, a charac-
teristic circuit breaking device, and a receiving instrument, a second characteristic
circuit breaking device insulated from the first, a motor for said circuit breaking
devices, a controlling magnet, a tap wire from said circuit on one side of said ther-
mostat and returning to said circuit on the other side of said thermostat and including
a magnet and said second circuit breaking device, contact points carried by said
magnet and its armature, a branch from one leg of said circuit to said controlling
magnet and to one of said contact points, and a second branch from the other leg of
said circuit to the other of said contact points, as and for the purpose described.
6-The combination of a closed metallic circuit including a series of thermostats,
a series of circuit breaking devices and a receiving instrument, a series of tap wires
each extending from said circuit on one side of a group of thermostats and returning
to said circuit on the other side of said group of thermostats, and each including a
magnet and one of said circuit breaking devices, a motor for said circuit breaking
devices, a controlling magnet, contact points carried by each of the magnets in the
tap wires and its armature, a branch from one leg of said circuit to the controlling.
magnet and to one of the contact points, and a second branch from the other leg of
said circuit to the other of said contact points.
7 The combination of a closed metallic circuit including a thermostat, a tap wire
from said circuit on one side of said thermostat including a magnet and returning to
said circuit on the other side of said thermostat, contact points carried by said:
magnet and its armature, a motor, a controlling magnet therefor, electrical connections
from said contact points to said controlling magnet including a switch, means
whereby said motor may open said switch, a ground branch, a contact point upon
which said switch is moved, and a second ground branch from said contact point,
whereby the controlling magnet may be demagnetized and then further energized, as
and for the purpose described.
8: The combination of a closed metallic circuit including a thermostat, a tap
wire from said circuit on one side of said thermostat including a magnet and returning
to said circuit on the other side of said thermostat, contact points carried by said
magnet and its armature, a motor. a controlling magnet therefor, a branch from one
leg of said circuit to said controlling magnet and to one of said contact points and
containing a switch, a second branch from the other leg of said circuit to the other
of said contact points, means whereby said motor may open said switch, a ground
branch, a contact point upon which said switch is moved, and a second ground branch
from said contact point, as and for the purpose described.
9 The combination of a normally closed metallic circuit, a battery and thermostat
therein a ground branch from said battery, a shunt around said thermostat including
a magnety a motor, a controlling magnet; contact points carried by said first named
maguet and is armature, a branch from one leg of said circuit to said controlling
magnet and to one of said contact points and including a switch, a second branch,
from the other leg of said circuit to the other of said contact points, means carried
by said motor and adapted to move said switch, a contact point upon which the switch

page_text: is moved, and a normally open branch from said last named contact point to the
ground including a thermostat, as and for the purpose described.
10-The combination of a normally closed metallic circuit, a battery, receiving
instrument and thermostat therein, a ground branch from said battery including a
receiving instrument, a shunt around said thermostat, including a magnet, a circuit
breaking device in said closed circuit, a motor, a controlling magnet, contact points
carried by said first named magnet and its armature, a branch from one leg of said
circuit to said controlling magnet and to one of sail contact points and including a
switch, a second branch from the other leg of said circuit to the other of said contact
points, means carried by said motor and adapted to move said switch, a contact
point upon which the switch is moved, and a normally open branch from said
last named contact point to the ground including a thermostat, as and for the
purpose described.
11-The combination of a normally closed metallic circuit, a battery, a receiving
instrument and a series of thermostats in said circuit, a ground branch from said
battery including a receiving instrument, a series of circuit breaking devices, a series
of shunts, one around each group of thermostats and each including a magnet and
one of said circuit breaking devices, a motor, a controlling magnet, contact points
carried by each of said first named magnets and its armature, a branch from one
leg of said circuit to said controlling magnet and to one of the contact points of each
of said first named magnets and including a switch, a second branch from the other
leg of said circuit to the other of said contact points of each of said first named
magnets, means carried by said motor and adapted to move said switch, a contact
point upon which the switch is moved, and a normally open branch from said last
named contact point to the ground including a thermostat, as and for the purpose
described.
12: The combination of a closed metallic circuit including a battery, a receiving
instrument, a thermostat, and a series of characteristic circuit breakers, insulated
from one another, a shunt around said thermostat and including one of said circuit
breakers, a branch from said battery to the ground including a receiving instrument,
a second branch from said circuit between the circuit breakers to the ground,
normally open and including a thermostat, as and for the purpose described.
13: The combination of a closed metallic circuit including a receiving instrument
an a battery, a branch from said battery to the ground including a receiving
instrument, a plurality of characteristic circuit breakers in said circuit, a motor
therefor, a second branch from said circuit between the circuit breakers to the
ground normally open and including a controlling magnet for said motor, and a
thermostat for closing said last named branch, as and for the purpose described.
14-The combination of a closed metallic circuit including a battery, a branch
from the battery to the ground including a receiving instrument, a normally open
branch from said circuit to the ground including a thermostat, a circuit breaker,
a motor, a controlling magnet, a relay in one leg of said metallic circuit and contact
points adapted to be closed when the circuit is broken, connections from one contact
point to the controlling magnet, to the circuit breaker and to the other leg of said
circuit, and connections from the other contact point to said normally open ground
branch, as and for the purpose described.
15: The combination of a closed metallic circuit including a battery, a branch
from the battery to the ground including a receiving instrument, a normally
open branch from the circuit to the ground including a thermostat, a circuit
breaker, a motor, two controlling magnets therefor, two relays, one in each leg of said
metallic circuit, and contact points adapted to be closed when the circuit is broken,
connections from one contact point of the first relay to one controlling magnet, to
the circuit breaker and to the opposite leg of the circuit and similar connections
from one contact point of the other relay to the other controlling magnet, to
the circuit breaker; to the opposite leg of the circuit, and connections from the
other contact points to said normally open branch, as and for the purpose described.
16-The combination of a normally closed metallic circuit, a receiving instrument

page_text: and a thermostat therein, a normally open ground branch from said circuit, a
thermostat and an alarm therein, a second ground branch from said circuit and a
receiving instrument therein, and a characteristic circuit breaker in each leg of said
circuit on either side of the connection therewith of the second ground branch,
whereby the same characteristic signal receive upon both receiving instruments
and upon the alarm, as and for the purpose described.
17 The combination of a closed metallic circuit including a thermostat, a motor,
an indicator frictionally connected with said motor, a tap wire from said circuit on
one side of said therinostat and returning to said circuit on the other side of said
thermostat and including a magnet, and a rod connected to the armature of said
magnet and adapted to be moved thereby into the path of sail indicator, as and for
the purpose described.
18 The combination of a closed metallic circuit including a thermostat, a receiving
instrument, and a characteristic circuit breaker, a tap wire from said circuit on one
side of said thermostat and returning to said circuit on the other side of said ther-
mostat and including a second characteristic circuit breaker, and a motor for said
circuit breakers, as and for the purpose described.
19: The combination of a closed metallic circuit including a thermostat, a
receiving instrument, and a characteristic circuit breaker, a tap wire from said
circuit on one side of said thermostat and returning to said circuit on the other
side of said thermostat and including a magnet and a second characteristic
circuit breaker, and a motor for said circuit breakers, as and for the purpose
described.
20 The combination of a closed metallic circuit including a series of thermo-
stats and a receiving instrument, a series of circuit breakers, a motor therefor, a
series of shunts, one around each group of thermostats and each including one of
said circuit breakers, as and for the purpose described.
21 The combination of a closed metallic circuit including a series of thermostats,
a circuit breaker, and a receiving instrument, a series of additional circuit breakers,
a motor for all of said circuit breakers, a series of shunts. one around each group of
thermostats and each including one of said series of circuit breakers, as and for the
purpose described.
22 The combination of a train of gear wheels, a pin in one of said wheels, a pin in
another and slower moving wheel, a lever having one end adapted to stand normally in
the path of said first mentioned pin, a controlling magnet and connection between the
armature of said magnet and said lever, whereby, when the magnet is momentarily
energized, the lever is moved from the path of said first pin and the train is
released, and when the magnet is energized for a longer time the end of the lever
is held in the path of the second pin and the train is stopped, substantially as
described.
23: The combination of a case having an aperture, a tube engaging said case,
a disk secured to the tube with fusible solder, an insulated post formed with a
shoulder, spring contact strips held in contact by the lower end of said post and other
spring contact strips held out of contact by the shoulder of said post, as and for
the purpose described.
Dated this 3rd day of December 1889.
ABEL & IMRAY,
Agents for the Applicant.