Improvements connected with Audible Telegraphs.
Year: 1892

page_text: Date of Application, 21st Sept., 1892
Complete Specification Left, 21st June 1893-Accepted, 21st Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements connected with Audible Telegraphs.
I, RICHARD ROBERT HARPER, of Sash Court, Wilson Street, Finsbury,
County of London, Electrical Engineer, do hereby declare the nature of this
invention to be as follows :-
The object of this invention is to transmit audible signals over long distances by
means of high tension induced intermittent currents without the use of relays.
In carrying out my invention, I place at the transmitting end of the distance to
be signalled over a signalling or Morse key an electro magnet with rheostat and an
induction coil with or without my improved sounder or receiver, and at the
receiving end my improved form of telephone sounder, hereinafter fully described.
The above appliances may be used on an ordinary single needle or such like
circuit upon the same line wire.
The method of connecting up working the above appliances upon a single needle
circuit is as follows;-The Morse key is connected by one wire with the battery,
the other wire passes to the contact screw of the rheostat, then from the armature
of same round the electro magnet to the primary coil of the induction coil, thence
to the battery. One terminal of the secondary circuit is connected to the telephone
receiver, which is preferably made with two diaphragms, the electro magnets of
which are rivetted or otherwise fastened to a U shaped piece of soft iron, said
magnets are connected up in series with the line wire to another similar receiver at
the other end, or distant station, thence to the single needle instrument and earth,
or return. The other terminal of the secondary circuit of the induction coil being
connected to the single needle instrument at the home end, and thence to earth.
To send signal, the Morse key is depressed from the battery and the current
connects up the electro magnet (the vibrating make and break arinature of which
now vibrates with great rapidity) thence through the primary wire of induction
coil, intermittent induced currents now pass from the secondary wire of the
induction coil through receiver to the line wire, thence through the receiver at the
distant station single needle instrument to earth, or return.
The intermittent currents upon passing through the receiver in consequence of
the rapidly vibrating make and break armature of the electro magnet produce upon
the diaphragms of the receivers a loud buzzing or drum like sound which through
following each other in such rapid succession practically produce no effect upon
the needles of the speaking instrument dials, any number of which may be in the
circuit.
In some cases, it may be found more convenient to send the induced currents
direct to line without passing through the receiver at the sending station.
The apparatus may be connected and used at any part of a single needle circuit,
viz. either at the terminal or intermediate stations.
When sending messages upon the single needle instrument the currents sent do
not interrupt the sounder apparatus, they being simply reverse currents while the
sounder currents are intermittent, therefore although these reverse currents pass
through the secondary wire of the induction coil, they have no effect upon the
make and break armature of the primary circuit in consequence of the electro
magnet with its make and break attachment being out of the magnetic influence of
the secondary wire of the induction coil, consequently intermittent currents work
the sounders only and reverse currents the single needle instruments only.
Dated this 21st dos of Sentember 1892.
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Richard Robert Harper.

page_text: COMPLETE SPECIFICATION.
Improvements connected with Audible Telegraphs.
I, RICHARD ROBERT HARPER, of Sash Court, Wilson Street, Finsbury,
County of London, Electrical Engineer, 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 :-
The object of this invention is to transmit audible signals over long distances by
means of high tension induced intermittent currents without the use of relays, and
consists in the employment of an electro-magnet or magnets, and vibrators if more
than one be used in conjunction with an induction coil, which may, or may not be
electrically coupled to my improved sounder or receiver at the transmitting end of
the line to be signalled over, all performing their several functions under the action
of a Morse key when a signal is transmitted which is audibly reproduced at the
receiving end by my before mentioned sounder or receiver in the manner, herein-
after fully described.
The above appliances may be used on an ordinary single needle, or such like
circuit upon the saine line wire at the same time and without interfering in any way
with each other.
My invention will be fully understood upon referring to the accompanying
3 sheets of drawings, in which
Figure is a plan of a combined transmitting appliance and receiver or
sounder.
Figure 2 is a sectional elevation of the same, while Figure 3 is a back elevation
of the receiver or sounder only with one diaphragm removed.
Figure 4, Sheet 2, is a diagrammatic view of the several parts involved in
Figures 1, 2, and 3 and system of electrical connection.
Figure 5, Sheet 3, is a diagrammatic view of a single needle circuit as connected
to my improved apparatus for duplex working.
The construction, method of connecting up and working the before mentioned
appliances upon a single needle circuit is as hereinafter described.
The transinitter consists of two spring plates A, B, constituting a double Morse
key arranged above their respective contacts A' B' and adjustable as to tension by
the set screws C, C, in the bridge piece D. Each plate is in electrical connection
with the electro magnet E through the vibrators or armatures F, F', which can be
regulated by the adjusting screws G, G, and back tension screws H, H, to produce
two distinctive sounds, or notes, musical, or otherwise from the receiver or sounder
at the end of the line wire.
I is an induction coil, the primary coil of which is preferably wound with wire of
high resistance to prevent the too rapid exhaustion of the battery in working,
and J is a condenser interposed in the circuit to absorb and prevent the ill effects
consequent upon the break contact when using the single needle instrument.
The receiver or sounder K which in duplex working is required at each end of
the line is preferably fixed upon the same base as the transmitter appliances, and it
consists of a rectangular, or other shaped box of wood or metal, upon two opposite
sides of which are fixed diaphragms L, L', of ferrotype iron or other suitable
metal or material, and between then is arranged a U shaped permanent magnet M
(or it may be of soft iron) with pole pieces N, NJ, and upon each pole piece N,N',
are fixed two electro magnetic coils or helices P, P, P, P, for receiving the
induced currents set up in the secondary circuit of the induction coil by
the vibrators or armatures F, FI, and thereby reproducing by means of
the diaphragms L, L', the sounds or notes occasioned by the before mentioned
vibrators or armatures F, F1, when the Morse key is depressed, as hereinafter fully
described.

page_text: The battery Q for working the before mentioned appliances is divided, and as
will be seen in the diagram Figure 4, Sheet 2, one part is joined to the terminal
communicating with the left hand key, and the other is in connection with the right
hand key, by thus dividing the battery between the two keys, I prevent the
polarization of the induction coil I and electro magnet E, as positive or negative
currents are transmitted according to the key used, so that any residual magnetism
set up in the coils is destroyed by the current reversals.
The diagram, Figure 5, shows a circuit in which 1, represents say, the home
station, 2, an intermediate, and 3, distant station respectively, all connected by a
single line wire g with a single needle instrument interposed at the intermediate
station 2 for reading a through message, I, I', being the induction coils of the
transmitters at the home and distant stations respectively, and K, K', are the
respective telephone receiver coils.
For the various local connections of the instrument and induction coils I, I',
reference must be had to Figure 4, in which it will be seen, the double Morse key
through its contacts A', B', is connected by wires a, a, with the battery Q, other
wires c, c, of each plate A, B, pass to the contact screws bb₁ respectively of the
vibrators F, F, then from the said vibrators F, F, round the electro magnet E to
one end of the primary coil I, or the electro magnet E may be dispensed with in
which case the vibrators F, FI would be operated by the core of the primary coil
of the induction coil I, the other end of the wire e being connected to terminal d,
thence to battery Q.
One terminal e of the induction or secondary coil I is connected by the wire f to
the telephone receiver K, K', and single needle instrument " at the distant end of
the line wire g which is in series with the sounder or receiver K, K, and single
needle instrument at the home end as particularly shown in Figure 5. The
receiver at the home end however may not be in connection, in which case, the
other terminal h of the secondary or induction coil will be connected by the wire i
to the terminal; communicating with the single needle instrument at the home
end, and thence by wire to terminal m and earth, as in Figure 5.
In working, it is understood that the distinctive sound or note emitted by the
receiver produced by the right and left hand plate A, B, respectively of the double
Morse key correspond to the right and left hand beats of a single needle instrument,
and either key separately, or both keys in conjunction may be used to transmit the
Morse code, or represent dots and dashes; but if each key is used separately to
transmit signals of course only one sound is emitted but as they are continuous
while the key is in contact, the sound representing the dash can be prolonged to any
desired extent, and long and short sounds of any relative length may be produced
at the will of the operator, and so unlike the telephone receiver which must be held
close to the ear, my improved sounder emits its note so loudly and of such a high
tone that it can be heard a distance away. It will be seen that the apparatus
constituting my invention, and which may be described as an audiphore, reduces
the risks of error in audible telegraphy to a minimum.
On the other hand, if both keys are used in conjunction to transmit the signals,
each key produces a distinctive note upon the receiver K, one sound representing
the dot, and the other, the dash, each of which may be of any length, all error as
to reading the message by mistaking fun
bing dot for dash, is obviated.
Although I have only described the apparatus as having r
one or two keys, it is
evident that any number may be used with corresponding vibrators or armatures,
each producing distinctive sounds or notes upon one and the same receiver, and
through the same line wire.
When sending messages upon the single needle instrument, the currents sent do
not interrupt the sounder apparatus, they being simply reverse currents, while the
sounder currents are intermittent, therefore although these reverse_currents pass
through the secondary wire of the induction coil, they have no effect upon the
make and break armature of the primary circuit in consequence of the electro
magnet with its make and break attachment being out of the magnetic influence

page_text: of the secondary wire of the induction coil, consequently intermittent currents
work the sounders only, and reverse currents, the single needle instruments
only.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. Producing sounds to constitute a signal by rapid make and break movements
of a vibrator or armaturé, and electrically transmitting said sounds by means of
induced currents set up in the secondary wire of an induction coil, by the vibrations
of said vibrator or armature, and receiving and audibly reproducing said sounds in
increased loudness by means of a sounder or receiver consisting of preferably a
box of suitable material covered on two opposite sides, with diaphragms of ferro-
type iron, or other metal or material operated or acted upon by electro-magnetic
coils or helices, through which the before mentioned induced currents are caused
to pass in the manner described, and substantially as shown in the annexed
drawings.
2. In an apparatus for electrically transmitting audible signal, the combination
of electro magnet E vibrators or armatures F, F', and induction coil I with a
telephone receiver K, each. performing their several functions under the action of
a Morse key in the manner described and substantially as shown in the drawings.
3. The system of connection or arrangement of appliances electrically coupled,
substantially in the manner shown on the drawing as above set forth.
Π
IXUR
MINI
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said R. R. Harper.