IMPROVEMENTS IN ELECTRIC TELEGRAPHS FOR GIVING SIGNALS AND ALARMS
Year: 1874

page_text: LETTERS PATENT to William Henry Davies, of 17 & 18, Cornhill, in
the County of Middlesex, and Frederick Herbert William Higgins,
of 17 and 18, Cornhill, in the County of Middlesex, for the Inven-
tion of "IMPROVEMENTS IN ELECTRIC TELEGRAPHS FOR GIVING SIGNALS AND
ALARMS."
Sealed the 17th April 1874, and dated the 19th February 1874.
PROVISIONAL SPECIFICATION left by the said William Henry Davies
and Frederick Herbert William Higgins at the Office of the Com-
missioners of Patents, with their Petition, on the 19th February
1874.
We, WILLIAM HENRY DAVIES, of 17 & 18, Cornhill, in the County of
Middlesex, and FREDERICK HERBERT WILLIAM HIGGINS, of 17 and 18,
Cornhill, in the County of Middlesex, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN ELECTRIC TELEGRAPHS FOR GIVING
SIGNALS AND ALARMS," to be as follows:-
-
The object of this Invention is to enable a large number of stations in
one circuit to communicate a limited number of call signals to a

page_text: receiving station or stations in such manner that without any skill on
the part of the operator the signal received will serve both to indentify
the station from which it was sent and also the nature of the call.
The transmitting instrument is provided with finger keys, conveniently
four in number, which serve to transmit as many call signals. The
depression of either of these keys winds up a spring which drives a train
of wheels giving motion to a cam wheel and also to a fly which regulates
the speed of the train in running down. The finger keys serve to
wind the spring to different amounts, one winds it sufficiently to rotate the
cam wheel once, another twice, and so on. There is a stop connection
with each finger key to ensure accuracy in its action. The cam wheel
has projections upon it which in passing act on a lever which breaks the
electric circuit. Each of the instruments in the circuit differs from all
the others in the arrangement of the projections upon its cam wheel,
and in connection with each instrument is a galvanometer coil and
needle simply to indicate when the line is free, as two operators must
not work simultaneously.
The instrument at the receiving station is of the Morse type, but
arranged to mark the paper whenever the current ceases to flow in the
line circuit, and the paper which receives the marks also starts into
motion whenever the electric circuit is broken, and stops shortly after
contact is again made.
In combination with the call instrument is used an automatic fire
alarm so arranged that upon the temperature of the room, floor, or
vault in which the apparatus is placed being raised beyond a pre-
determined point a thermostat liberates its mechanism by the expansion
of a metal, either directly by the bursting of a graduated glass ball and
stem filled with mercury, or by means of the shifting of a contact
maker and diversion of the current of electricity (which is constantly
flowing through the instruments) from its direct path to another through
an electro-magnet whose armature retains the trigger of the call in-
strument in position ready for sending a signal. By this means a large
warehouse or factory can be connected by a single wire with the police
office and fire-engine house miles distant, and with any number of inter-
mediate alarms, or with every pile of goods and every floor up to about
200 for a single wire. Each signal would indicate the position of the
fire....

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 19th
August 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
HENRY DAVIES, of 17 & 18, Cornhill, in the County of Middlesex,
and FREDERICK HERBERT WILLIAM HIGGINS, of 17 and 18, Cornhill,
in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of February, in the year of
our Lord One thousand cight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said William Henry Davies and Frederick
Herbert William Higgins, Her special license that we, the said William
Henry Davies and Frederick Herbert William Higgins, our executors,
administrators, and assigns, or such others as we, the said William
Henry Davies and Frederick Herbert William Higgins, our exccutors,
administrators, and assigns, should at any time agree with and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN ELECTRIC
TELEGRAPHS FOR GIVING SIGNALS AND ALARMS," upon the condition (amongst
others) that we, the said William Henry Davies and Frederick Herbert
William Higgins, our exccutors or administrators, by an instrument in
writing under our or their hands and scals, or under the hand and seal
of one of us or them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that we, the said William Henry Davies and
Frederick Herbert William Higgins, do hereby declare the nature of the
said Invention, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following state-
ment thereof, that is to say :-

page_text: (
The object of this Invention is to enable a large number of stations in
one circuit to communicate a limited number of call signals to a
receiving station or stations in such manner that without any skill on
the part of the operator the signal received will serve both to identify
the station from which it was sent and also the nature of the call.
The transmitting instrument is provided with finger keys, conveniently
four in number, which serve to transmit as many call signals. The
depression of either of these keys winds up a spring which drives a train
of wheels giving motion to a cam wheel, and also to a fly, which regulates
the speed of the train in running down. The finger keys serve to wind
the spring to different amounts, one winds it sufficiently to rotate the
cam wheel once, another twice, and so on. There is a stop in connection
with each finger key to ensure accuracy in its action. The cam wheel
has projections upon it which in passing act on a lever which breaks the
electric circuit. Each of the instruments in the circuit differs from all
the others in the arrangement of the projections upon its cam wheel,
and in connection with each instrument is a galvanometer coil and
needle simply to indicate when the line is free, as two operators must
not work simultaneously.
The instrument at the receiving station is of the Morse type, but
arranged to mark the paper whenever the current ceases to flow in the
linc circuit, and the paper which receives the marks also starts into
motion whenever the electric circuit is broken, and stops shortly after
contact is again made.
Call instruments, such as above described, we also use as automatic
fire alarms. We combine them with the thermostats so arranged that
upon the temperature of the room, floor, or vault in which the apparatus
is placed being raised beyond a pre-determined point the thermostat
liberates the mechanism, for example, by the bursting of a graduated
glass bulb and stem filled with mercury, freeing the trigger of the call
instrument. By this means large warehouses or factories can be con-
nected by a single wire with the police office and fire-engine house miles
distant, and with any number of intermediate alarms, or every pile of
goods, and every floor may have its automatic fire alarm up to about
200 for a single wire. Each signal would indicate the position of the
fire.
In order that our said Invention may be most fully understood and

page_text: I
Figure 1 is a front view of the apparatus for communicating at
pleasure, by means of finger keys, several different calls signals to a
distant receiving station.
Figure 2 shews also a front view of the same apparatus with the case
removed.
:
Figure 3 is a side view with some portions removed in order that other
parts of the mechanism may be more clearly seen.
a, a, is the frame of the apparatus; it is arranged to be fixed against
a wall in an upright position, as shewn, and it carries two insulated
couplings b and c by which it is connected with the line wires passing to
and from it. The coupling 6, by a wire b', is in electrical connection
with the metal frame of the instrument. The coupling c is in electric
connection with a line wire and with one extremity of a galvanometer
coil d and, except as herein-after mentioned, it is insulated from the
other parts of the apparatus. It will be understood that a large number
of these instruments at as many different places are included in the
same circuit, together with a recording instrument at the receiving
station, which records upon a strip of travelling paper the breaks of
electric continuity in the circuit. e is a cam wheel which, when caused
to revolve (one, two, or more times, and by means herein-after described
in detail) produces a series of breaks in the electric circuit, each rise in
the cam corresponding with a break of electric continuity in the circuit.
Each of the many instruments employed has a different form of cam
wheel although in other respects they are identical.
.
"The way in which the rotation of the cam breaks the electric circuit is
as follows:-A lever f, capable of turning on a centre at f', carries a
small friction pulley f which a light coiled spring f³ holds in contact
with the periphery of the cam, hence when the cam revolves a rocking
motion is communicated to the lever.. When the pulley f' is bearing on
a part of the cam between the projections the point f, which is of
platinum and is fixed to the lever f, bears against a platinum face g¹at
the end of the spring which is fixed upon the insulated piece h
attached to the frame, the picce / is in electrical connection with the

page_text: galvanometer coil; so long therefore as the point f' is in contact with gʻ
there is a complete path for the current between the couplings b and c
through the galvanometer coil, and the current from the battery at the
receiving station flows through the entire circuit. When in the rotation
of the cam e, the pulley f bearing upon one of the projections of the
cam, the point f' is removed from contact with the surface g¹ and the
circuit is broken.
The break of the circuit causes an electro-magnet in the receiving
instrument to release its armature which is then carried away from it
by a spring and a mark is produced upon the recording paper of the
instrument, in all respects as when in the ordinary Morse instrument
the electro-magnet attracts its armature. Thus the cam e of any one of
the instruments in circuit when it revolves produces breaks in the
circuit. These breaks in the first place cause the needle & of the
galvanometer coil d to vibrate, and this takes place in every instrument
in the circuit, shewing that the line is in use and that a moment's delay
must be submitted to before another signal can be made again. At the
receiving station the breaks in the circuit result in marks being made
on the paper of the receiving instrument in a sequence dependent on
the form of the particular cam which happens to be in motion, the
sequence of marks enables the clerk at the receiving instrument to
identify the sending station from which the call signal has been sent,
and the number of times this sequence of marks is repeated informs him
of the nature of the call. h¹, h³, h³, h, are the finger keys of the
instrument, and it remains only to describe how it is that by first
depressing and then releasing one or other of these keys the cam is set
in motion at a suitable speed, and proceeds to make one, two, three, or
four revolutions, according to the finger key employed. When a finger
key is put down against the resistance of its spring h* its inner end comes
against the platform i, which is held by a spring, and is able to slide
along the guides . The platform is pushed by the keys along the
guides a distance dependent on the length of the finger key employed,
and the keys are so proportioned that key h³ moves the platform twice
the distance which it is moved by key h¹, h³ three times, and h* four
times respectively. k is an incline or pin projecting from the platform i,
against it a spiral rests, and when the platform is pushed back the
motion of the pin k rotates the spiral. m is a coiled spring attached at
one end to the frame, and at the other to the axis of the spiral 1, so

page_text: that this spring is wound up more or less by the rotation of the spiral,
and it tends to rotate the axis so as to bring the spiral back. nisa
toothed wheel mounted loosely on the axis ', it carries a pawl n' which
drops into the teeth of a ratchet fixed on the axis ₁, so that when this
axis turns under the influence of the spring m it is compelled to carry
the wheel n with it. The wheel n drives the pinion o which is fixed
upon the same axis with the cam e. There is also an escapement
wheel p on this axis; it works with an anchor escapement to which a
short adjustable pendulum q¹ is attached. The object of this arrange-
ment is to control the speed of rotation of the cam wheel so that the
record of the receiving instrument may be clear and distinct.
As the spiral is rotated by the spring m it pushes the platform i
forward ready to be again acted on by the finger keys. A supplementary
spring may be applied to aid the spring m. in moving the platform. ris.
a contact piece in electric connection with the coupling c. through the
galvanometer coil d. When the platform i is in its forward position.
(which it occupies at all times except when it has just been removed by
the finger keys) a stud upon it comes against the piece r and provides a
second path for the electric current, so that the working of the entire
system may not be deranged by an imperfect contact occurring
at f' and g¹ in any one of the many instruments in circuit.
The instrument shewn has four finger keys, but this may obviously be
varied, the cam wheel e being arranged so that it can repeat its rotations
more or less than four times, as may be necessary. The conventional
meanings attached to the several call signals will be varied to suit the
requirements of each particular circuit.
Figures 4, 5, and 6, of the annexed Drawings shew the apparatus
combined with a thermostat as an automatic fire alarm. Figure 4 is a
front view; Figure 5 is a similar view with the case removed; Figure 6
is a side elevation with the case in section. This arrangement is so
similar as respects many of the parts, and as respects its mode of action
to the apparatus already described, that a detailed explanation is
unnecessary, the parts being lettered as in 1, 2, and 3. The finger
keys and all parts connected with their action are dispensed with,
the axis having an index or handle & at its upper end by which it can
be turned partly round to wind up the spring and set the apparatus
ready for use when the apparatus has been wound. As soon as the
index or handle is set free the signal is given, and the nature of the

page_text: signal will of course correspond to the form of the cam e, which is
different in different instruments, the index or handle is however
retained when the instrument is set by inserting into a socket, made in
the case to receive it, the short thermometer glass 8, and the index or
handle is then stopped by resting against the thermometer bulb. In 5
this condition the apparatus is placed in the situation which it is desired
to watch for fire. A slight rise in the temperature over summer heat
causes the thermometer bulb to burst in consequence of the expansion
of the mercury it contains beyond the extent of the space allowed for it
in the stem, thus the index or handle is set free and at once the signal 1
is given.
What we claim is, the combination of apparatus enabling a number of
stations in one circuit to communicate a limited number of call signals
to a receiving station, substantially as described.
We also claim the combined arrangement of apparatus enabling a 11
number of automatic fire alarms in one circuit to communicate each its
distinctive signal to a receiving station, substantially as described.
In witness whereof, we, the said William Henry Davies and
Frederick Herbert William Higgins, have hereunto set our hands
and seals, this Eighteenth day of August, in the year of our Lord 20
One thousand eight hundred and seventy-four.