IMPROVEMENTS IN TELEGRAPHIC SIGNALLING INSTRU- MENTS FOR TRANSMITTING A NUMBER OF FIRE AND OTHER ALARMS OR CALLS UPON A SINGLE WIRE
Year: 1874

page_text: LETTERS PATENT to William Henry Davies and Frederick Herbert
William Higgins, both of 17 & 18, Cornhill, in the City of London,
for the Invention of "IMPROVEMENTS IN TELEGRAPHIC SIGNALLING INSTRU-
MENTS FOR TRANSMITTING A NUMBER OF FIRE AND OTHER ALARMS OR CALLS
UPON A SINGLE WIRE."
Sealed the 11th September 1874, and dated the 15th July 1874.
PROVISIONAL SPECIFICATION left by the said William Henry Davies
and Frederick Herbert William Higgins at the Office of the
Commissioners of Patents, with their Petition, on the 15th July
1874.
We, WILLIAM HENRY DAVIES and FREDERICK HERBERT WILLIAM
HIGGINS, both of 17 & 18, Cornhill, in the City of London, do hereby
declare the nature of the said Invention "IMPROVEMENTS IN TELEGRAPHIC
SIGNALLING INSTRUMENTS FOR TRANSMITTING A NUMBER OF FIRE AND OTHER
ALARMS OR CALLS UPON A SINGLE WIRE," to be as follows:-
This Invention has for its object improvements in telegraphic
signalling instruments for transmitting a number of fire and other

page_text: alarms or calls upon a single wire. For this purpose the calls are made
by the interruption of a current which is always kept flowing through
the line and instruments in its circuit. Every interruption by releasing
the armature of a relay is recorded upon the tape of an instantaneous
self-starting Morse register.
Any number of combinations may be used, each indicating something
previously determined upon.
The object of the improvements is to diminish the great length of the
signals and consequent danger of interruption, and also to simplify and
increase the number of calls which each instrument can make, without
necessitating any very complicated and easily deranged apparatus.
All signals will be of the same length, and the different disposition of
the groups of interrupting slots on the contact discs herein-after
mentioned will indicate from which instrument the signal is being sent
and what it means.
The machine consists of a train of two wheels and a pinion driven by
a watch barrel spring, which is wound sufficiently for each signal by the
depression of either of the signalling keys placed in the front of the
instrument. To the axis of one of the wheels of the train are fixed four
slotted metal discs with four contact springs pressing upon their
peripheries. These springs are connected by wires with four insulated
metal plates, which are fixed under the pointer moved by the keys in
such a position that the pointer makes contact with the one opposite the
key depressed. Upon depressing a key the spring is wound by a pawl
engaging the tooth of a wheel until a projection from the pawl strikes
against a fixed pin in the frame of the instrument; the continued
upward movement of the end of the key lever lifts it out of the tooth
and releases the train of wheels, and revolves the contact-breaking discs
once. The keys are placed radially; the ends of the levers converge to
within a short distance of an upright axle which carries an eccentric.
To this axle is attached the circuit changing picce or pointer which
connects the different contact springs to the line.
The manner in which the circuit changer follows the movement of
the keys is by making the eccentric from a diagonally cut tube, and
causing the ends of the levers to move in the plane of its axle. The
upward movement of the leyers is always limited by the top of the cut
in the tube. The depression of a. key therefore causes the line to be.

page_text: connected to the disc indicating that signal, the spring to be wound,
and the train released, independently of the time the key was being
depressed or released, and always without those jerks which in previous
machines tended to derange the signals by shortening the first
interruption.
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 15th
January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
HENRY DAVIES and FREDERICK HERBERT WILLIAM HIGGINS, both of
17 and 18, Cornhill, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifteenth day of July, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, 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
executors, 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
TELEGRAPHIC SIGNALLING INSTRUMENTS FOR TRANSMITTING A NUMBER OF FIRE
AND OTHER ALARMS OR CALLS UPON A SINGLE WIRE," upon the condition
(amongst others) that we, the said William Henry Davies and Frederick
Herbert William Higgins, our executors or administrators, by an
instrument in writing under our or their hands and seals, or under the
hand and seal of one of us or them, should particularly describe and

page_text: 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 I, the said Frederick Herbert William Higgins,
on behalf of myself and the said William Henry Davies, 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 statement thereof, that is to say :—
This Invention has for its object the construction of apparatus by
which any number of transmitting stations coupled up in one circuit
may communicate to one receiving station certain pre-arranged alarms
or calls. Each transmitting station has the power to transmit several,
say four, such calls, which will be understood at the receiving station,
and from the nature of the signal the transmitting station from which it
was sent will be at once identified. We effect this in the following
manner :—At the receiving station there is in circuit a battery, and also
an instrument of the Morse type which registers by a mark upon a
travelling strip of paper every interruption in the continuity in the
electric circuit. The strip of paper is started automatically as soon
as signals commence to be transmitted by means which are well
understood.
The transmitting instrument which constitutes the peculiar feature of
our Invention is arranged with a number of finger keys corresponding
in number to the calls to be transmitted, say four, and when either of
these keys is depressed it winds up a clockwork train, which then rotates
an axis on which there are a number of metal discs, one for each call to
be transmitted. Each disc has notches in its periphery, and a contact
spring bears upon it. As the disc revolves the spring rests in metallic
contact with it, except when one of the notches passes beneath the
spring, and then a breech of metallic continuity occurs. The notches
on the several dises are differently arranged, and however many may be
the number of transmitting instruments in circuit the contact discs are
all differently formed. The depression of any finger key also operates a
switch which controls the flow of the electric current through the
instrument; it moves a spring arm and causes it to touch a metallic
stud coupled with the contact spring of the disc corresponding with the-

page_text: finger key operated upon, and the current then flows through this spring
and disc alone. The other springs and discs of the instrument, although
the discs are rotated, are inoperative. As the clockwork runs down, and
each notch in succession of the disc which is in circuit passes beneath
its contact spring, the flow of the current throughout the entire line
circuit is momentarily arrested, and a corresponding mark is made upon
the travelling paper of the receiving instrument.
By employing in each transmitting instrument a separate notched disc
for each alarm or call to be transmitted, in place of distinguishing
between several alarms or calls by causing one disc to rotate a greater or
less number of times, as is proposed in the Specification of a former
Patent granted to us, and dated the 19th February 1874, No. 640, we
are able very much to shorten the signals, and to include a much greater
number of transmitting instruments in one circuit without inconveniently
crowding the line.
In order that our said Invention may be most fully understood and
Figure 1 is a front view of the instrument; it may be fixed against a
wall in any convenient position, and is provided with two binding
screws a and b for coupling the instrument with the line wire. The
screw a is insulated from the case. c¹, c², c³, c, are the finger keys
corresponding with the several calls, say, for example, "fire," "police,"
messenger,"
""cab."
"
The internal mechanism of the instrument is shewn in Figures 2
and 3. Figure 2 is a side view, the case having been removed, and
Figure 3 is a back view, also without the case. In Figure 2 only one
finger key is represented; the others are omitted to avoid confusion
in the Drawing. Either of the finger keys when acted upon gives
motion to a link d, which is jointed at one end to an arm e on the axis ƒ.
g is a lever jointed to the link d intermediate of its length, and at its
lower end this lever turns upon a stud attached to the frame of the
instrument; d' is a pin at the end of the link d, against which the key
levers press; c* are springs, one to each key lever, to return the key to
its original position as soon as it is liberated; h is a coiled mainspring

page_text: attached to one end of the frame, and at the other to the axis f, and
when the axis f is turned partly round by the action of the finger keys
this spring is wound up; i is a ratchet wheel of ten teeth fixed upon
the axis f; a pawl / engages with its teeth. This pawl is mounted upon
a centre at k¹ on the face of the spur wheel 1, and it is provided with a
spring ² pressing it into the teeth of the ratchet. The wheel gears
with the pinion m fixed on the same axis with the escapement wheel n,
with which the anchor escapement o engages. p is a short pendulum
attached to the escapement o. The arrangement of this train is more
clearly seen at Figure 4, which is a section of so much of the instrument
taken on the line 1, 1, in Figure 3. It will be seen that when a finger
key is depressed the ratchet allows the axis f to turn independently of
the wheel 1, but when the key is released and the spring / tends to
rotate the axis fin the contrary direction, the ratchet causes it to take
the wheel with it, thereby giving motion to the escapement wheel n
and to the pendulum p, which consequently regulates the speed at which
the mainspring recovers itself. In this way the four notched contact-
breaking discs q, which are fixed upon. the axis of the escapement
wheel n, are caused to rotate at a suitable speed, and they make one
complete revolution each time after a finger key has been depressed.
", ", are the contact springs resting on the peripheries of these discs.
They are separately attached to the insulating block of vulcanites, and
are connected respectively with the four metal studs t which this block
carries. u is an axis, the end of which passes through the block s; it is
insulated from the frame, and carries at its end the spring finger u³. vis
a cylinder or short tube fixed upon the axis u, but not in metallic
contact; it is notched or cut away on one side to a V form, and when
cither of the key levers is depressed its end comes against the end of
this tube or cylinder, and pressing against the incline turns it and the
axis to which it is attached, until finally the end of the key is stopped
when it reaches the bottom of the angular notch, and by this time the
axis will have been turned to the extent necessary to bring the finger u¹
into contact with the metallic stud corresponding with the finger key
which has been depressed. The disc q, whose spring is coupled with
the stud on which the finger u¹ rests, is then in circuit and ready to
operate when the finger key is allowed to return, whilst the other discs
are placed out of contact and are inoperative. w is a small galvanometer
coil containing a magnetised needle, to which by a light arm an
indicator x is attached; by it the operator may know when the line is

page_text: free, as any interruption taking place in the continuity of the circuit
sets the indicator in motion. One end of the galvanometer coil wis
connected to the binding screw a, and the other to an insulated stud y,
which by a coiled wire is connected with the insulated axis u. Thus,
the current may be traced through the instrument as follows:-From
the binding screw a, through the galvanometer coil wo to the axis u,
through the finger ¹ to one of the studs t, thence through the corre-
sponding spring r and disc wheel q to the frame of the instrument, and
so to the binding screw b. The galvanometer coil w is not however
required to be constantly in circuit, and when not in use it is shunted
by the spring, which is attached to the binding screw a and rests upon
the insulated stud y. ¹ is a vulcanite peg, which when depressed by
the finger removes the spring from contact with the stud y.
Having thus described the nature of our said Invention, and the
manner of performing the same, we would have it understood that we
claim as our improvements in telegraphic signalling instruments for
transmitting a number of fire and other alarms or calls upon a single
wire, the combination of a scries of finger keys with a clockwork train
driving contact-breaking discs and a switch, in such manner that each
key when depressed winds and liberates the train which rotates the
contact-breaking discs, and also operates the switch to throw into circuit
the particular disc which corresponds with the said key, substantially as
described.
We also claim the general arrangement of the apparatus, substantially
as described and shewn in the annexed Drawings.
In witness whereof, I, the said Frederick Herbert William Higgins,
have hereunto set my hand and seal, this Fifteenth day of
January, in the year of our Lord One thousand eight hundred
and seventy-five.