IMPROVEMENTS IN TELEGRAPHIC APPARATUS ESPECIALLY FOR STREET FIRE ALARMS
Year: 1882

page_text: LETTERS PATENT to William Henry Davies and Frederick Herbert William
Higgins both of 17 and 18 Cornhill in the City of London, for an Invention
of " IMPROVEMENTS IN TELEGRAPHIC APPARATUS ESPECIALLY FOR STREET
FIRE ALARMS"
PROVISIONAL SPECIFICATION left by the said William Henry Davies and
Frederick Herbert William Higgins at the Office of the Commissioners of
Patents on the 8th March 1882.
WILLIAM HENRY DAVIES and FREDERICK HERBERT WILLIAM HIGGINS both of
17 and 18 Cornhill in the City of London " IMPROVEMENTS IN TELEGRAPHIC
APPARATUS ESPECIALLY FOR STREET FIRE ALARMS
"
The object of this Invention is to render the signals made from street fire alarm
boxes self interpreting and to reduce and simplify the apparatus and operations
necessary for the transmission and reception of such signals
For this purpose we employ as receiver a dial which is in appearance like that
of a clock-A pointer which is controlled by a step by step propelment actuated by
an electromagnet indicates the locality whence an alarm has been made by pointing
to its name.
The propelment electro-magnet is in the same circuit as the signalling posts line
and a battery-An interruption of the circuit at any point causes the pointer of
the receiving instrument to be moved one step or to half way between the zero or
starting point and the first name the restoration of the circuit causes it to point to
the first name
Such a signal would be made by the first alarm box in the circuit
Upon the occurrence of such an interruption an alarm bell upon the top of the
dial is caused to ring and continues to do so until the signal has been acknowledged
by pressing a button at the bottom of the dial.
The acknowledgment of reception is made by reversing the direction of the
current flowing through the line which brings a disc into view in an aperture with
the words "signal received" upon it
In order that the propelment magnet may not be affected by the reversal of the
battery current or by the cessation of the current which occurs for an instant while
the reversing switch is in motion it is placed in circuit between the battery
and the switch and the latter is arranged to shunt the electro magnet wires in
the interval of change
The polarity of the electro magnet is thus constant in direction and is maintained
by the circulation of the induced current

page_text: The shunt consists of two strips of brass each moveable about a pin at one end
which connects it with an ebonite block The strips are connected together by an
ivory link and are moved simultaneously by a pin on the lever carrying the press
button. Their free ends are thus caused to pass over the faces of three contact
studs each strip passing from one stud to the next and they are sufficiently wide to
make contact on one stud before leaving the other
A lever which is canted in one direction by the first movement of the propelment
completes the bell-ringing circuit
It is canted back to its normal position by the Key which makes the acknow-
ledgment The same Key also restores the pointer to zero The key acts against
an incline or cam on the axis of the pointer unclutches it from the escapement
axis shifts it round to the zero point and then allows the clutching parts again to
engage
The alarm signalling boxes contain a train of wheels with a spring which is
wound and discharged by pulling a handle in the face of the instrument
The time necessary for the proper transmission of the signal is regulated by an
escapement with weighted arms gearing with a wheel in the train having ratchet
teeth and there is a contrivance for detaching the pull handle from the mechanism
from the beginning until the completion of each signal
Upon the axis of the ratchet wheel there is a cam wheel with projections and
each projection in passing by lifting a contact making lever interrupts the circuit―
The cam wheel makes one revolution to complete the signal.
The cams in each box in one circuit differ in number of projections and con-
sequently in the displacement which the resulting interruptions of the circuit effect
in the position of the pointer of the receiving instrument
The stem of the pull handle has a projection upon it which when the pull is
drawn out comes against a jointed finger carried upon an arm on the driving axis
The arm is drawn forward with the pull until at the point when the spring is fully
wound the projection escapes over the end of the finger The spring then propels
the axis the train commences to run and the signal given During the outward
movement of the pull handle the joint by which the finger is connected with the
arm on the driving axis does not come into play but on the return of the pull
handle the joint yields to let the projection on the stem of the handle pass. The
joint is provided with a spring operating in a manner of a knife spring and it
retains the finger when it is thus laid back as in the opening of a knife and it is
not until the lever has come back almost to the starting point that the finger is so
far closed up to the lever that it springs back into position to be operated by the
pull handle
A circuit closer or shunt actuated by the door of the box is employed to reduce
the resistance of the circuit and protect the galvanoscope coils from lightning
when not in use In closing the door of the instrument the glass presses against a
pin and brings together two spring blades connected to the extremities of these
coils as soon as the glass is broken or the door opened these springs separate and
the current flows through the coils. In the receiving instrument there is a
graduated slit in the dial and a needle in connection with a galvanometer in circuit
shows through the slit and indicates when the strength of the battery current is
within the range of adjustment of the receiving instrument
We employ another method in some cases for producing in the receiving instru-
ment the signals from the Street Fire Alarm boxes We replace the pointer before
mentioned by a contact maker which when arrested in any position makes electrical
contact with an indicator and brings the name of the post into view in an aperture
in the dial of the instrument
There are then as many separate indicators as there are posts in circuit and the
action of the rotating contact maker which takes the place of the pointer in the
previously mentioned apparatus is to make contact with the required shutter
indicator and so bring into view its name

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Henry Davies and Frederick Herbert William Higgins,
in the Great Seal Patent Office on the 8th September 1882.
WILLIAM HENRY DAVIES and FREDERICK HERBERT WILLIAM HIGGINS both of
17 and 18 Cornbill in the City of London " IMPROVEMENTS IN TELEGRAPHIC
APPARATUS ESPECIALLY FOR STREET FIRE ALARMS
"
The object of this Invention is to render the signals made from street fire alarm
boxes self interpreting and to reduce and simplify the apparatus and operations
necessary for the transmission and reception of such signals.
For this purpose we employ as receiver a dial which is in appearance like that
of a Clock. A pointer which is controlled by a step by step propelment actuated
by an electromagnet indicates the locality whence an alarm has been made by
pointing to its name.
The propelment electromagnet is in the same circuit as the signalling posts line
and a battery An interruption of the circuit at any point causes the pointer of
the receiving instrument to be moved one step or to half way between the zero
or starting point and the first name the restoration of the circuit causes it to
point to the first name.
Such a signal would be made by the first alarm box in the circuit.
Upon the occurrence of such an interruption an alarm bell upon the top of the
dial is caused to ring and continues to do so until the signal has been acknowledged
by pressing a button at the bottom of the dial.
The acknowledgment of reception is made by reversing the direction of the
current flowing through the line which brings a disc into view in an aperture with
the words "signal received" upon it.
In order that the propelment magnet may not be affected by the reversal of the
battery current or by the cessation of the current in the line which occurs for an
instant while the reversing switch is in motion it is placed in circuit between the
battery and the switch and the latter is arranged to shunt the electro magnet wires
off the line circuit in the interval of change.
The polarity of the electro magnet is thus constant in direction and is maintained
by the circulation of the induced current.
The shunt consists of two strips of brass each moveable about a pin at one end
which connects it with an ebonite block. The strips are connected together by an
ivory link and are moved simultaneously by a pin on the lever carrying the press
button. Their free ends are thus caused to pass over the faces of three contact
studs each strip passing from one stud to the next and they are sufficiently wide to
make contact on one stud before leaving the other.
A Lever which is canted in one direction by the first movement of the pro-
pelment completes the bell ringing circuit. It is canted back to its normal
position by the key which makes the acknowledgment. The same key also restores
the pointer to zero, the key acts against an incline or cam on the axis of the pointer
unclutches it from the escapement axis shifts it round to the zero point and then
allows the clutching parts again to engage.
The alarm signalling boxes contain a train of wheels with a spring which is
wound and discharged by pulling a handle in the face of the instrument.
The time necessary for the proper transmission of the signal is regulated by an
escapement with weighted arms gearing with a wheel in the train having ratchet
teeth and there is a contrivance for detaching the pull handle from the mechanism
from the beginning until the completion of each signal.
Upon the axis of the ratchet wheel there is a cam wheel with projections and
each projection in passing by lifting a contact making lever interrupts the circuit.
The cam wheel makes one revolution to complete the signal.

page_text: The cams in each box in one circuit differ in number of projections and con-
sequently in the displacement which the resulting interruptions of the circuit effect
in the position of the pointer of the receiving instrument.
The stem of the pull handle has a projection upon it which when the pull is
drawn out comes against a jointed finger carried upon an arm on the driving axis.
The arm is drawn forward with the pull until at the point when the spring is fully
wound the projection escapes over the end of the finger. The spring then propels
the axis the train commences to run and the signal is given. During the outward
movement of the pull handle the joint by which the finger is connected with the
arm on the driving axis does not come into play but on the return of the pull
handle the joint yields to let the projection on the stem of the handle pass. The
joint is provided with a spring operating in a manner of a knife spring and it
retains the finger when it is thus laid back as in the opening of a knife and it is
not until the lever has come back almost to the starting point that the finger is so
far closed up to the lever that it springs back into position to be operated by the
pull handle.
A circuit closer or shunt actuated by the door of the box is employed to reduce
the resistance of the circuit and protect the galvanoscope coils from lightning when
not in use. In closing the door of the instrument the glass presses against a pin
and brings together two spring blades connected to the extremities of these coils
as soon as the glass is broken or the door opened these springs separate and the
current flows through the coils. In the receiving instrument there is a graduated
slit in the dial and a needle in connection with a galvanometer in circuit shews
through the slit and indicates when the strength of the battery current is within
the range of adjustment of the receiving instrument.
We employ another method in some cases for producing in the receiving instru-
ment the signals from the Street fire alarm boxes. We replace the pointer before
mentioned by a contact maker which when arrested in any position makes
electrical contact with an indicator and brings the name of the post into view in
an aperture in the dial of the instrument.
There are then as many separate indicators as there are posts in circuit and the
action of the rotating contact maker which takes the place of the pointer in the
previously mentioned apparatus is to make contact with the required shutter
indicator and so bring into view its name.
In order that our said Invention may be most fully understood and readily
carried into effect we will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front elevation of the receiving instrument.
Figure 2 is a back elevation, the back of the case being removed.
Figures 3 and 4 are right and left side elevations of the apparatus.
A is an electro magnet which attracts and releases an armature B. The
armature is attached to a lever carrying pallets C. C. which propel a ratchet D.
A spring throws back the armature from the magnet when the attraction ceases.
A retaining pawl and ratchet control the action of the propelment in the usual
manner.
A tubular axis surrounding the axis of the propelment carries the index E, and
the two axes are clutched together by a friction or pin clutch at F.
G. is a scroll cam on the axis of the index, and H, is a finger or lever having its
fulcrum at H¹. The lever terminates in front in a press button H².
When the press button is thrust in, the finger comes against the scroll cam and
pushing it forward unclutches the axis of the index from that of the propelment;
the finger then turns the index to the zero point.
When the finger is allowed to return by the operation of its spring the index
axis is also brought back by a small coiled spring which does not appear in the
drawings; and the two axes are again clutched together.

page_text: The armature B carries an arm B¹, and when it leaves the magnet the arm
strikes the light lever I into contact with the screw K. The lever I is retained by
a small spring having a doubly inclined head; there is a pointed stud projecting
from the boss of the lever and this is made to pass from side to side of the doubly
inclined head of the retaining spring
The return of the lever I takes place when the button H2 is pushed in, an
incline H3 on the finger then comes against the lever and pushes it over.
Z is a block of vulcanite carrying the two metal strips L', and L³, pivoted to it
by their upper ends; these strips together with the three insulated contact studs
M, M, and M³, constitute the reversing switch. N is an ivory link connecting the
strips L, L, A pin H*, fixed into H, enters a hole in the link N, so that the
finger H in its movements carries the contact strips L', L³, with it and changes
the electrical connections.
O is a trembling bell of the ordinary description. P¹, P³, P³, P', P³ and Pe are
binding screws.
Qis a galvanometer, it serves to shew the strength of the current the upper end
of its needle is visible through a slit in the dial.
The electrical connections of the instrument are as follows:-
The terminals P' and P2, belong to the local battery for ringing the hell. P' is
connected with the metal frame work of the instrument and through this with the
small lever 1. When the lever is in contact with the screw K (which is otherwise
insulated from the frame) the bell is in circuit, the bell terminals being connected,
the one with the cock through which the screw K passes and the other with the
terminal P
Ps and P, are the main battery terminals P, the earth and P6 the line. P³ (the
zinc of the battery) is connected with the coil of the magnet A, and thence with
the metal strip L¹.
Normally the strip L' is in contact with the stud M³, and this is connected
with P and earth.
The circuit then is from zinc of the battery, through the coils of the magnet to
earth. The return is from line through the galvanometer Q to the stud M₁ thence
by the strip L to the battery terminal Pt.
When now the circuit is interrupted at one of the signal posts the armature B
falls away from the magnet and the propelment operates, making one step; it
makes a second when the circuit is reestablished. The falling away of the
armature also causes the bell to sound in the manner already explained.
When the button H2 has been pushed in to acknowledge the call, the strip L',
has passed into contact with the stud M³, and the strip L2, is in contact with the
stud M².
The circuit is then from zinc of the battery, through the coils of the magnet in
the same direction as before; thence by L' to Ms. M³ is permanently connected
with M and so the current passes through the galvanometer Q, to line but in the
reverse direction. The return is by earth, to the stud M2 and the strip L³, which
is connected with the copper terminal.
The strips L', L³, are sufficiently wide to make contact with one stud before
leaving the other so that the battery circuit through the magnet coils is never
opened.
In some cases as already proposed it may be convenient to arrange the index E
as a circuit closer, to transmit a call current to one or other of a series of electrical
"enumciators" which may be situate in any desired positions.
Figure 5 is a front elevation of the transmitter employed at the alarm
signalling boxes.
Figure 6 is a back elevation of the instrument removed from the case.
Figure 7 is a side elevation, the case in section.
Figure 8 is a plan, the case in section.
Figure 9 is a side elevation of a portion of the mechanism.

page_text: a. 18 an axis to which one end of a coiled spring b is attached the other end of
the spring is fixed to the frame.
c is an arm fast upon the axis a. d is a finger connected with the arm c. it
can turn freely about the axis a.
In Figure 7 the finger is seen in its normal position; that is to say it is held by
the spring c¹ attached to the arm c. in contact with a pin c. on the same arın.
e is a pull which is drawn out when it is desired to make a signal; the pull is
afterwards brought back by its spring e'.
e is a pin upon the pull which when the pull is drawn out comes into contact
with the finger d. The finger with the arm c are then drawn forward together
and the axis a, is turned partly round.
f is a ratchet upon the axis a, and when the axis has been turned as described
the pawl g drops into the teeth of the ratchet and retains the axis.
The pull e. however, goes back at once, the pin e. strikes the finger d and lays it
down but without affecting the arm c. the spring c¹ yielding.
The axis a, slowly returns carrying with it the wheel h, upon which the pawl g
is mounted; this wheel gears with and drives the pinion i which is on the same
axis with a ratchet j. The ratchet is retained by the escapement k which vibrates
to allow the teeth of the ratchet to pass. The speed of vibration can be adjusted
by screwing the heavy nuts k¹. 1. in or out along the screw arms k². k³.
As the axis a with the arm c, and the finger d, return the finger. comes into
contact with a fixed stop and presently it is brought into such a position in
relation to the arm c. and the spring c¹ that the finger flies back to its original
position.
The axis of the ratchet j carries an ivory cam j¹. and this has as many rises upon
it as may be required to give the call signal of the particular post at which the
instrument is in use. As shewn in the drawing there are three rises upon the cam
and the signal is made by opening the circuit three times.
The cam in rotating raises the lever m. off the contact screw n and the lever is
immediately brought back by its spring m'.
o is a galvanometer, the axis of the needle carries an arm upon which is a disc o'
and when the needle is deflected by a reversal of the current made as already
described at the receiving station for the purpose of acknowledging a call, the disc
is raised in front of the aperture in the case at p.
q. q. are two insulated blades of metal which when free spring apart but when
the door of the instrument is shut the glass with which the door is glazed comes
against a stud r and pushing it in brings the spring blades q. together.
The circuit may be traced through the instrument as follows. From the binding
screw at 8 which is in metallic connection with the line wire, to one of the
blades and thence to the other blade q either direct if the door of the instrument
be closed or by the coils of the galvanometer if the door has been opened or the
glass broken for the purpose of giving a call signal. Thence to the piece on which
is the fulcrum of the lever m. this piece is insulated from the frame, through the
lever m to the contact screw n. The cock which carries the screw n is insulated
from the frame and connected with the binding screw at t. and this is connected
with the line wire passing forward to the next post.
Having thus described the nature of our said Invention and the manner of
performing the same we would have it understood that we claim :-
1
First. The combined telegraphic apparatus applicable especially for street fire
alarms consisting of a normally closed battery circuit including a station instru-
ment in which an electro-magnet actuating a propelment moves an index or
indicator each time that the circuit is opened; and a series of signal posts with
instruments which open the circuit a prearranged number of times when a pull
is drawn out or other like simple movement is made substantially as herein
described.
Second. The combined telegraphic apparatus applicable especially for street
fire alarms consisting of a battery circuit including a station instrument in

page_text: which an electro-magnet actuating a propelment moves an index or indicator, and
a series of posts with instruments in which the Drawing out of a pull or other
like simple movement gives motion to a cam; such cams differing in each post and in
each being of a form suitable to intermit the current the number of times required
to transmit the call signal of the post of which it belongs substantially as herein
described.
Third. The receiving or station instrument, with its arrangements for acknow-
ledging the call by the reversal of the current through the line without affecting
the propelment substantially as herein described.
Fourth. The post or transmitting instrument in which the Drawing out of a
pull or other like simple movement causes the rotation of an axis under the control
of a speed regulator such axis having upon it a cam with as many projections as
are required to transmit the call signal of the post to which the instrument belongs,
substantially as herein described.
Fifth. In the post or transmitting instrument the parts by which the movement
of the pulle is transmitted to the axis a and by which the free return of the pull
is permitted without interference with the said axis substantially as herein
described.
In witness whereof I the said Frederick Herbert William Higgins have
hereunto set my hand and seal this Seventh day of September in the year
of our Lord One thousand eight hundred and eighty two.