Improvements in the Means or Apparatus for Transmitting Electric Signals.
Year: 1889

page_text: Date of Application, 23rd Aug., 1889
Complete Specification Left, 9th May, 1890-Accepted, 14th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in the Means or Apparatus for Transmitting Electric
Signals.
1, ERNEST JULES PIERRE MERCADIER of 1 Boulevard St. Denis, Paris, France,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention consists of what may appropriately be termed an inductophone and
which is composed of:
:-
1st. A vibrating body of suitable form, as for example a spring plate or a diapason,
the vibrations of which are maintained electrically by the complete or partial
automatic interruption of an electric current traversing one or more electro-magnets
situated in the vicinity of the vibrating body.
2nd. One or more coils or bobbins with soft iron core placed in the magnetic field
of the electro-magnets and connected together in series or for quantity.
The coils which are in the intermittent magnetic field may appropriately be called
inductophonic coils.
Owing to the intermittences of this magnetic field the number of which is equal to
that of the vibrations of the vibrating body, induction currents of the same number
are produced in the inductophonic coils. Therefore, if the two ends of the set of coils
be made to communicate with a receiver capable of producing sounds when it is
traversed by intermittent or undulatory currents, like a telephone for example, this
receiver produces a sound the number of vibrations of which is equal to that of the
electric undulations or intermittences, that is to say the actual sound of the
vibrating body.
Hence my apparatus or system can be utilized for producing telephonic calls at a
distance, or for producing telegraphic signals, by placing in the circuit of the.
inductophonic coils a manipulator and the primary wire of an induction coil, the
secondary wire of which communicates with a telegraph line. These signals could be
utilized in ordinary telegraph systems, in the system of multiplex telegraphy which I
have described in a prior Patent Specification, No. 10363 of 1888 and generally in
all systems of telegraphic or telephonic communications which can be established by
the aid of intermittent or undulatory currents of determined periods, as for instance
the systems of station calls established in a single circuit in derivation or otherwise.
The means of maintaining the vibrations is the same in all cases, whether the
vibrating body be a diapason or a spring plate; it is an electro-magnet, one of the
ends of which communicates with the vibrating body itself and the other end with
the pole of a battery the other pole of which is connected to a platinum. plate mounted
on a screw; as soon as this plate touches a steel style fixed to the vibrating body
this begins to vibrate, and its movement is maintained by the currents that pass
through the electro-magnet at each contact of the style and plate. There may.jbe
several electro-magnets instead of one.
The currents are not completely interrupted on account of the sparks arising from,.
the extra currents which maintain between the style and the plate a flow of
electricity; in fact there is a maintaining current which varies only much in
intensity during a vibration of the vibrating body; these variations are of the same.
number as those of the vibrations, and it is the same with the variations of intensity, of
the magnetic field which is formed around the electro-magnet.
There are produced, as I have said, undulatory induction currents of the same.
number in the inductophonic coils placed in this magnetic field.
In one arrangement of the inductophonic. coil it is wound around that of the.
electro magnet; this has a feeble resistance, 2 or 3 ohms.; the other has great resist.
ance, 150 to 200 ohms.

page_text: In order to apply the mode of transmission which I call inductophonic to
telegraphy I can dispense with the induction coil, make one of the ends of the
inductophonic coil communicate with earth and the other with the front piece of an
ordinary Morse manipulator the body of which communicates with the line. The
receiver can be an ordinary sensitive telegraph receiver or a telephone the binding
screws of which are connected the one to earth and the other to the back piece of the
manipulator like a Morse receiver; the inductophonic coil would thus be treated as an
ordinary battery.
In order to apply my invention to the system of multiplex telegraphy described in
my said former Specification it would only be necessary to substitute inductophonic
transmitters producing different sounds for the microphonic transmitters described in
the said Specification; the receivers and the communications would remain the same.
My system of inductophonic transmission works practically without difficulties. It
does away with batteries on the lines.
D
11
09
COMPLETE SPECIFICATION.
Improvements in the Means or Apparatus for Transmitting Electric
Signals.
I, ERNEST JULES PIERRE MERCADIER of Boulevard St. Denis, Paris, France,
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 :-
My invention consists of what may appropriately be termed an inductophone, and
which is composed of :-
1st. A vibrating body of suitable form as for example a spring plate or a diapason
the vibrations of which are maintained electrically by the complete or partial
automatic interruption of an electric current traversing one or more electro magnets
situated in the vicinity of the vibrating body.
2nd. One or more coils or bobbins with soft iron core placed in the magnetic field
of the electro magnets and connected together in series or for quantity.
The coils which are in the intermittent magnetic field may appropriately be called
inductophonic coils.
Owing to the intermittences of this magnetic field the number of which is equal to
that of the vibrations of the vibrating body induction currents of the same number
are produced in the inductophonic coils. Therefore if the two ends of the set of coils
be made to communicate with a receiver capable of producing sounds when it is
traversed by intermittent or undulatory currents, like a telephone for example, this
receiver produces a sound the number of vibrations of which is equal to that of the
electric undulations or intermittences, that is to say the actual sound of the
vibrating body.
Hence my apparatus or system can be utilized for producing telephonic calls at a
distance, or for producing telegraphic signals by placing in the circuit of the induc-
tophonic coils a manipulator and the primary wire of an induction coil the secondary
wire of which communicates with a telegraph line. These signals could be utilized in
ordinary telegraph systems, in the system of multiplex telegraphy which I have
described in a prior Patent Specification No. 10363 of 1888 and generally in all
systems of telegraphic or telephonic communications which can be established by the
aid of intermittent or undulatory currents of determined periods, as for instance the
systems of station calls established in a single circuit in derivation or otherwise.
Figures 1 and 2 of the annexed drawings represent an inductophone the vibrating
body of which is a diapason D of steel or iron fixed on its sound box G; and
Figure 3 represents an inductophone the vibrating body of which is a vibrating
plate V of steel or iron.

page_text: In the examples of inductophonic arrangements herein before described there is a
stationary maintaining electro magnet opposite vibrating and consequently movable
bodies, the maintaining electro magnet may however be fixed to the vibrating body
and movable with it, but in this case it is necessary for the maintaining of the move-
ment that the core of the electro magnet should be in a magnetic field.
Figure 5 represents a type of instrument of this class with a vibrating plate, the
electro magnet having a double wire. The letters V, E, S. P, p, f, f¹ refer to the
same parts as in Figure 3. There is also in addition a magnet whose ends A and B
are as seen in the plan of the apparatus, Figure 6, a little in front of the core of the
electro magnet E. A curser c allows by its displacement of varying the number of
vibrations of the plate. The apparatus is so arranged that the contact of the plate P
with the style S causes the current from the battery p to pass into E so that the
poles 6 and a of the magnetized core may be the reverse of those of the fixed magnet.
The movement of E and of V (that is from back to front) takes place and is main-
tained automatically.
The effect thus produced can be increased by placing the core of E between four
poles of fixed magnets A and B and two others which I will call A¹ and B'; B¹ being
opposite A on the other side of 6 and A¹ opposite B on the other side of a. Strictly,
it would be sufficient in order to produce the above effects for A and B in
Figures 5 and 6 to be fixed pieces of soft iron. The induced currents produced in the
second wire ff of the electro magnet E are of the same nature as in the other types
of inductophone, viz.-currents due to the variation of the magnetic field of E and
currents due to the movement of V in relation to A and B.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The apparatus or instrument hereinbefore called inductophone constructed as
set forth.
2. The means or system herein described of transmitting telephonic and telegraphic
signals with the aid of the said inductophone which transmission is hereinbefore called
inductophonic transmission.
3. The application or adaptation of this system to telephony and telegraphy in cases
where intermittent or undulatory electric currents can be employed such as telephonic
calls, station calls, and simple or multiplex telegraphy, as set forth.
Dated the 0th CM 1900
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent' Agent.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent' Agent.

page_text: The means of maintaining the vibrations is the same whether the vibrating body
be a diapason or a spring plate; it is an electro magnet E one of the ends f, f of which
communicates with the vibrating body itself and the other end with one pole of
a battery p the other pole of which is connected to a platinum plate P mounted
on a screw; as soon as this plate touches a steel style S fixed to the vibrating body
this begins to vibrate, and its movement is maintained by the currents that pass
through the electro magnet, at each contact of the style and plate. The electro
magnet E is fixed to a board represented at A, K, C. F in Figures 1 and 2 and
which is fixed to the support of the vibrating body. There may be several electro
magnets instead of one.
The currents are not completely interrupted on account of the sparks arising from
the extra currents which maintain a flow of electricity between the style and the
plate; in fact there is a maintaining current which varies only much in intensity
during a vibration of the vibrating body; these variations are of the same number as
those of the vibrations and it is the same with the variations of intensity of the
magnetic field which is formed around the electro magnet E.
There are produced as I have said undulatory induction currents of the same
number in the inductophonic coils placed in this magnetic field.
In Figure 1 I have shown one of the coils I and the connection of its two ends with
the primary wire 1-1 of an induction coil B and with the manipulator N introduced
into the circuit, the secondary wire 2, 2 being connected on the one side to earth and
on the other to a telegraph line L. It will be seen that it is sufficient to make the
manipulator move in order to send through the line L signals formed by the
undulatory currents arising from an induction of a sort of second order produced in
the coil B.
Instead of a single inductophonic coil I I can employ several around the
vibrating body in the field of the electro magnet E, their ends being suitably
connected.
Figures 2, 3 and 4 represent another arrangement of the inductophonic coil; it is
wound around that of the electro magnet E; this has a feeble resistance, two or three
ohms.; the other has great resistance, 150 to 200 ohms., as when it is separate in the
magnetic field (Figure 1) the wires ff are those of the coil of the electro magnet;
their electric communications are the same as in Figure 1; they are represented
diagrammatically in Figure 4 around the soft iron core a, b. The wires f₁, f₁ are
those of the inductophonic coil; they are connected to the induction coil Bas
in Figure 1.
1
In order to apply the mode of transmission which I call inductophonic to
telegraphy I can dispense with the induction coil B, make one of the ends of the
inductophonic coil communicate with earth and the other with the front piece of an
ordinary Morse manipulator the body of which communicates with the line. The
receiver can be an ordinary sensitive telegraph receiver or a telephone the binding
screws of which are connected the one to earth and the other to the back piece of the
manipulator like a Morse receiver; the inductophonic coil would thus be treated as
an ordinary battery.
In order to apply my invention to the system of multiplex telegraphy described in
my said former Specification it would only be necessary to substitute inductophonic
transmitters producing different sounds for the microphonic transmitters described in
the said Specification; the receivers and the communications would remain
the same.
My system of inductophouic transmission works practically without difficulties. It
does away with batteries on the lines.
It is obvious that the induced currents resulting from the movement of the vibrating
body D or V in the field of the electro magnet are added to those which are produced
by the variations of intensity of this field.
It need hardly also be remarked that the inductophones can be graduated; by
means of cursers placed upon the vibrating body the number of its variations and
consequently of the induced currents can be varied.