IMPROVEMENTS IN FIRE ALARM TELEGRAPHS
Year: 1888

page_text: I HENRY ALFRED CHARLES SAUNDERS Electrician and I ALFRED CHARLES BROWN
Electrician both of 11 Old Broad Street London E.C. do hereby declare the nature of
our invention for IMPROVEMENTS IN FIRE ALARM TELEGRAPHS to be as follows
._
These improvements relate to that class of Telegraph in which a separate wire is
used to connect a Fire-station with each of the Call-points in its district.
The improvements are designed to fullfil the following conditions found necessary
in the actual working of such apparatus.
1. To give an effective call, irrespective of the callers actions with the knob, after
he has once pulled.
2. To keep the Linc under continual test for contacts etcr. but to make a distinc-
tion between rings arising from such, causes and real calls from the Call-point.
3. To enable replies to be sent in answer to the Calls, and conventional signals to be
sent by the Fire-inen, both from, and to, the posts, without requiring any batteries in
the posts.
Our apparatus at the Fire-station consists of a Battery having one pole connected
to Earth, and the other joined through an ordinary Trembling-Bell movement, to one
side of each of the drop-coils of an ordinary Electric bell Indicator together. The
other side of the Indicator drop coils are joined to the lines to their respective Call-
points.
The Bell-movement is however shunted by a wire resistance, or arranged for the
vibrating armature contact to short-circuit its own coils instead of breaking the circuit
thereof; or other means adopted to prevent the making and breaking of the vibrating
armature contact from producing any momentary interruptions of the Line-circuit.
Or a relay instead of the Bell, may be placed in the direct Line-circuit, and arranged
so that the closing of its armature-contact shall ring the Bell in a local circuit, the
Bell then working in the ordinary way. A Reply-key for breaking the Line-circuit,
is also inserted between the Battery, and Bell, or relay.
The Apparatus at the post consists of an Electromagnet, and an armature so arranged
that when it is pulled towards the electro-magnet, it makes an electrical contact with

page_text: the iron core thereof, but is otherwiso normally insulated therefrom. (The iron core
and armature being both platinised for the purpose of making contact when together.)
(Or the Contact may be between a pair of Springs pulled together by the Armature.)
The armature is connected to the Line from the Fire-station.
I
The iron core of the Electromagnet is also insulated from the main framework and
is connected to one side of its own coils.
The other side of the coils are connected to one side of those of a trembling bell
also placed in the post and arranged like the one at the Station, so that the making
and breaking of its vibrating armature contact does not produce any momentary
interruptions of the Line-circuit.
The other side of the trembling bell movement is connected to Earth. The key-
contact armature is normally sprung a long way off the magnet, but is arranged to be
pulled up to it mechanically when the knob is pulled. The knob can however go
back again freely without pushing back the armature with it. When the knob is
pulled therefore, the circuit is completed from Line, through the coils of the Electro-
magnet & bell, to Earth, & since the Key armature is then held up to its contact
magnettically by the current from the Station, (notwithstanding that the knob may be
released,) the circuit then remains completed permanently until broken by the reply-
key at station. This lets go the armature, and restores the normal open-circuit
condition of the Line.
When a Call is given therefore, the bell in the post sounds together with the one
at the Fire-station and its being stopped by the Reply-key at Station forms a Reply-
signal to the Caller. A Disc may also be fixed on the key contact-armature, to be
moved in front of a little window, so as to give a visible, as well as audible signal,
on its being released by the Reply-key. A small Signaling button is also provided
in the Call-point, arranged to connect the end of the Line to Earth through the
trembling bell, on its being pressod the contact being made at a point of the
circuit between the Key magnet coils, and those of the bell, so that by pressing the
button the bells both in the post and at the Station may be rung together inter-
mittantly, without pulling down the Permanent Current key armature. Conventional
signals can thus be sent by the Firemen from the Post to the Station, and if the
fireman at the post holds down his button, the Station can also reply to the Post, by
means of their Reply-key. Contact rings are distinguishable from real calls on this
system, by the latter always giving continuous rings which stop permanently when
the Reply-key is pressed, while the former are irregular rings which either stop
before the Reply-key is pressed, or else fail to stop then.
Dated this Sth day of March 1888.
HENRY ALFRED CHARLES SAUNDERS.
ALFRED CHARLES BROWN.

page_text: I HENRY ALFRED CHARLES SAUNDERS (Electrician) and I ALFRED CHARLES
BROWN (Do.) both of Winchester House Old Broad Street in the City of London, 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:-
These improvements relate to that class of Telegraph in which a separate wire is
used to connect a Fire Station with each of the Call-points in its district.
The improvements are designed to fullfill the following conditions found necessary
in the actual working of such Apparatus.
1. To give an effective Call, irrespective of the Callers actions with the knob, after
he has once pulled.
2. To keep the Line under continual test for Contacts &c., but to make a distinction
between rings arising from such causes and real Calls from the Call-point.
3. To enable replies to be sent in answer to the Calls, and conventional Signals to
be sent by the Firemen, both from, and to, the Posts, without requiring any Batteries
in the Posts.
Our Apparatus at the Fire-station consists of a Battery having one Pole connected
to Earth, and the other joined through an ordinary trembling-Bell movement to one
side of each of the drop coils of an ordinary Electric Bell Indicator together. The
other side of the Indicator drop coils are joined to the Lines to their respective Call-
points. The Bell-movement is however shunted by a wire resistance, or arranged for
the vibrating armature contact to short-circuit its own coils instead of breaking the
circuit thereof, or other means adopted to prevent the making and breaking of the
vibrating armature contact from producing any momentary interruptions of the Line-
circuit. Or a Relay instead of the Bell may be placed in the direct Line-circuit, and
arranged so that the closing of its armature contact shall ring the Bell in a local
circuit, the Bell then working in the ordinary way. A Reply-key for breaking the
Line-circuit is also inserted therein between the Battery and Bell or Relay.
The Apparatus at the Post consists of an Electromagnet and an armature, so
arranged that when it is pulled towards the Electromagnet, it makes an electrical
contact with the iron core thereof, but is otherwise normally insulated therefrom, the
iron core and armature being both platinised for the purpose of making good contact
when together. Or the contact may be between a pair of springs, or spring and fixed
stud, pulled together by the armature. The armature, or one of the contact-springs
that are moved thereby, is connected to the Line from the Fire-station. The other
spring, stud, or iron core of the Electromagnet, which is then also insulated from the
main framework, is connected to one side of its own coils. The other side of the coils
are connected to one side of those of a trembling-bell also placed in the post, and
arranged like the one at the Station, so that the making and breaking of its vibrating
armature contact does not produce any momentary interruptions of the Line-circuit.

page_text: The other side of the trembling bell movement is connected to Earth. The koy-
contact armature is normally sprung a long way off the magnet, but is arranged to be
pulled up to it mechanically when the knob pulled. The knob can however go
back again freely, without pushing back the armature with it.
When the knob is pulled therefore the circuit is completed from Line through the
coils of the Electromagnet and Bell, to Earth, and since the key armature is then
held up to its contact magnetically by the current from the Station, (notwithstanding
that the knob may be released,) the circuit then remains completed permanently, until
broken by the Reply-key at Station. This lets go the armature, and so restores the
normal open circuit condition of the Line.
When a Call is given therefore, the Bell in the Post sounds together with the one
at the Fire-Station, and its being stopped by the Reply key at Station so forms a
Reply Signal to the Caller.
A Disc may also be fixed on the key contact armature, to be moved in front of a
little window in Call-point box, so as to give a visible as well as audible signal on its
being released by the Reply key.
A small Signalling button is also provided in the Call-point, arranged to connect
the end of the Line to Earth through the trembling bell on its being pressed, the
contact being made at a point of the circuit between the key magnet coils, and those
of the bell, so that by pressing the button the bells both in the Post and at the Station,
may be rung together intermittantly, without pulling down the permanent current
key armature.
Conventional signals can thus be sent by the Firemen from the Post to the Station,
and if the Fireman at the Post holds down his button, the Station can also reply to
the Post, by means of their Reply-key.
Contact rings are distinguishable from real Calls on this system, by the latter
always giving continuous rings which stop permanently when the Reply-key is
pressed, while the former are irregular rings which either stop of themselves before
the Reply-key is pressed, or else fail to perinanently stop then.
The accompanying Drawings shew the form in which we generally prefer to
manufacture these Instruments, but their details may be largely varied.
Where a
visible Reply signal is wanted also the key-armature must either be so mounted that
its plane of motion is nearly parallel with the Instrument front plate, or intermediate
parts provided to turn the motion of the Disc round thereto.
DESCRIPTION OF DRAWINGS.
Figs. 1, 2, and 3, are respectively front, side, and back, elevations of the Call-point,
in which A is the Base-plate which screws into the Post and carries all the Instrument
parts, B the Pull-knob with plunger attached and which slides in a hole in the
enlarged boss C, on base plate A. It is kept pushed back by a spiral spring contained
within the boss C, and bearing at one end on the Base-plate and at the other on the
enlargement on back of Pull-rod B. The plunger B is prevented from turning round
by a pin working in a slot in the boss C as shewn, and also carries a stout spring D
which is bent up at right angles and forms the back stop for the armature E of the
Electromagnetic key, the coils of which are shewn at F. This armature is carried by
a lever O pivotted in an upright bracket P, which is insulated from the main frame-
work, and the lever O is also electrically insulated from the armature E. The
armature E is normally pulled away from the electromagnet. by a spiral spring Q₂
hooked at one end through the tail of lever O, and at the other through the bottom of
bracket Pas shewn. Gis a Contact spring fixed into lever O, and arranged to be
pulled up against a Contact stud H, fixed over, but insulated from the base of
bracket P, on the armature E being pulled up towards its electromagnet F on the
pulling of the knob by hand. The Line-Terminal screws directly into bracket P, but.
is insulated through the base plate A and Contact stud H. The Earth Terminal
screws directly into the base plate A. I J K are respectively the electromagnet
armature, and short circuiting contact stud, for the trembling bell L which acts as a

page_text: repeater bell in the Post. This Bell and its stud are omitted in Fig. 2, in order to
more clearly shew the Contact spring G and stud H. M is a contact spring, fixed to
stud K, and arranged to make contact with a projection on bracket P on being pressed
by hand by means of the button N. This is for enabling the Firemen to send
conventional signals without pulling down the permanent current key armature E.
The Diagram Fig. 4, represents the arrangements at the Station, which consist of
an ordinary Electric Indicator, Bell, and Battery, and a Key for breaking the circuit
by hand. These are not shown in detail as any ordinary forms may be used, the only
essential being that the Bell shall not at any time break the direct Line or Battery
circuit, which may be accomplished by arranging it in any of the manners described
above.
The Electric connections will be made clear by the dotted lines on the accompanying
Drawings without further description.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what
we claim is:
1. In an Electric Fire Alarm Telegraph, the use and employment of an Electro-
magnetic koy, at the Call-point, operating to close the Line-circuit between the
Station and Earth through its own coils on its armature approaching the electro-
magnet on the knob being pulled, and so arranged that when the circuit is once thus
closed it shall remain closed permanently until broken at another point, notwithstanding
that the Pull-knob may be released.
2. The combination with an Electromagnetic-key at the Call-point as above
described, of an ordinary Electric Indicator, Bell, Battery and Reply key at the
Station, the Bell being arranged so that the vibration of its armature does not at any
time break the direct Line circuit, and the Reply-key operating to break the Line
circuit on its being pressed.
3. The combination with the Electromagnetic-key and Station Apparatus as
described above, of a Repeater Bell in the Post, arranged to ring simultaneously with
the Station Bell, for the purpose of giving an audible Reply-Signal, and as, and for
the other purposes described above.
4. The use and employment of the means described above, and illustrated in the
accompanying Drawings of pulling up the electromagnetic key armature mechanically,
on the pulling of the knob by hand, while allowing it normally to stand a long way
off its electromagnet, and thereby to keep its contacts normally a long way apart, so
as to be out of danger of closing from any jerking of the Post.
5. The use and employment in combination with the parts illustrated in Figs. 1, 2,
and 3, of the accompanying Drawings, of the ordinary Ringing-key M, and Button N,
for conventional signalling purposes, as above described.
6. The combination with each other of the various Mechanical parts and Electrical
connections, described above, and illustrated in the accompanying Drawings.
Dated this Seventh day of December 1888.
H. A. C. SAUNDERS.
A. C. BROWN.