Improvements in and relating to Telephonic Apparatus of the Ader System.
Year: 1891

page_text: Date of Application, 28th Apr., 1891
Complete Specification Left, 21st Jan., 1892-Accepted, 27th Feb., 1892
PROVISIONAL SPECIFICATION.
[ Communicated from abroad by SOCIÉTÉ GÉNÉRALE DES
TÉLÉPHONES
(Reseaux Téléphoniques et Constructions Electriques), of 41, Rue Caumartin,
Paris, France, Manufacturers.]
Improvements in and relating to Telephonic Apparatus of the
Ader System.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Patent Agent, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in and relating to telephonic apparatus of
the Ader system.
The transmitter is made of a box shape, the cover of which opens on hinges and
carries the vibrating membrane, to the middle of which are attached two pieces of
carbon. One of these pieces is made with a projecting hook shaped end that
extends over the end of the other piece. The two opposite faces of these pieces
are sloped in such a manner as to present a V-shaped space between them, and
into this space is placed the one end of a third piece of carbon, so as to make
contact with each of such sloping faces.
This third carbon is of a rod shape and extends horizontally parallel with the
mevibrane, and near the middle of its length it is pivotted by a pin to a supporting
har carried by the cover, such pivot being sufficiently beyond the middle to cause
the end of the rod to bear with part of its weight on the surfaces of the V groove.
The said rod may either be entirely of carbon, or only that part may be of carbon
which rests on the other two pieces, the other part being made of metal or other
suitable material; or it may even be entirely of metal. The electric circuit passes
from the one pole of the battery to the support of the said rod and thence through
the pivot into the rod, and if necessary a further conducting connection may be
made between the two by a flexible wire coil, arranged so as not to interfere with
the action of the rod.
From the other pole of the battery the conductor branches to the opposite ends
of two primary windings of an induction coil, and the other ends of such windings
are connected respectively to the two fixed carbon pieces. In place of a single
induction coil, two may be used, in which case, each would have only a single
primary winding, which may either be in parallel or in series.
By means of this simple construction of transmitter very powerful effects may
be obtained with comparatively weak currents.
In place of a battery, a small magneto electric machine may be used. Instead
of having only a single horizontal contact rod as described, two such may be
arranged in line with each other on opposite sides of the two fixed contact
pieces.
Or there may be two or more separate sets of contact pieces such as above
described arranged at different parts of the membrane.
When speaking into a powerful telephonic transmitter, the line currents in
passing through the local receiver, operate in such manner as to have the
effect of speaking into the ear of the operator, thereby interfering with the
communications.
In order to avoid this according to the present invention the secondary circuits
are arranged as follows. The induction coil has two secondary circuits and the
bobbins of the local receiver also have two windings; the one secondary circuit of
the induction coil is connected to one of the windings of the receiver bobbin, and

page_text: passes thence to the line wire, that is to say, it is an ordinary telephonic circuit;
the second secondary winding of the induction coil is formed into a closed circuit
with the secondary winding of the receiver bobbin, thus forming only a local
circuit.
From the above it will be seen that, on speaking, the currents of the two
circuits will neutralise each other in the local receiver, and the above mentioned
inconvenience will be avoided.
Instead of having the last named circuit on the same induction coil as the first
one, it may be on a second induction coil through the primary circuit of which is
led the same current that passes through the primary circuit of the first induction
coil.
Or instead of having a second winding on a single induction coil, a shunt circuit
from the single winding may be connected to the receiver bobbin.
In very hot climates the liquids of the batteries in evaporating rapidly, cause
considerable inconvenience and trouble in maintaining the batteries in proper
order.
"
In order to avoid this inconvenience, and also for other purposes, such batteries
may be replaced by small magneto electric machines commonly called " magnetos
such as are used for the call bells. For this purpose there is introduced into the
revolving armature of the magneto firstly the ordinary induced circuit which serves
for producing the currents for the calls, and secondly another circuit of about one
Ohm resistance, which second circuit serves in lieu of the battery of the
transmitter, the currents from each circuit being collected by a separate set of
brushes.
The ordinary commutator with automatically acting hook is arranged to close
the circuit for the calling current and to break the transmitter circuit when the
telephone receiver is hooked on; when this is unhooked, the commutator is made
to break the calling circuit, and closes the receiver circuit. Of course, with this
arrangement it is requisite to operate the magneto all the time speaking is
going on.
Dated this 28th day of April 1891.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Telephonic Apparatus of the
Ader System.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Patent Agent, 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:—
This invention relates to improvements in and relating to telephonic transmitting
apparatus of the Ader system.
The transmitter is made of a box shape, the cover of which opens on hinges and
carries the vibrating tympan to the middle of which are attached two pieces of
carbon. One of these pieces is made with a projecting hook shaped and that
extends over the end of the other piece. The two opposite faces of these pieces
are sloped in such a manner as to present a V-shaped space between them, and into
this space is placed the one end of a third piece of carbon, so as to make contact
with each of such sloping faces.
This third carbon is of a rod shape and extends horizontally parallel with the
tympan and near the middle of its length it is pivotted by a pin to a supporting
bar carried by the cover, such pivot being sufficiently beyond the middle to cause
the end of the rod to bear with part of its weight on the surfaces of the V-groove,

page_text: The said rod may either be entirely of carbon, or only that part may be of carbon
which rests on the other two pieces, the other part being made of metal or other
suitable material, or it may even be entirely of metal. The electric circuit passes
from the one pole of the battery to the support of the said rod and thence
through the pivot into the rod, and if necessary a further conducting connection
may be made between the two by a flexible wire coil, arranged so as not to
interfere with the action of the rod.
From the other pole of the battery the conductor branches to the opposite ends
of two primary windings of an induction coil, and the other ends of such windings
are connected respectively to the two fixed carbon pieces. In place of a single
induction coil, two may be used, in which case each would have only a single
primary winding which may either be in parallel or in series.
By means of this simple construction of transmitter very powerful effects may
be obtained with comparatively weak currents.
In place of a battery, a small magneto electric machine may be used. Instead
of having only a single horizontal contact rod as described, two such may be
arranged in line with each other on opposite sides of the two fixed contact
pieces.
Fig. 1 of the accompanying drawings shews a front view of the above described
box shaped transmitter with the cover open.
Fig. 2 shews a horizontal section on line M N and
Fig. 3 a vertical section on line PQ.
Two pieces of carbon C C' are fixed on a vertical vibrating tympan M; these
two pieces, at the point where they are opposite each other, are formed with
inclined faces so as to present a V-shaped space between them, in which is placed a
third piece of carbon B so as to rest upon the inclined surfaces of C C and thus
make contact with the two pieces.
The piece B is by préference made as two separate contact pieces each of which
extends parallel to the vibrating tympan M and is pivotted at T near the middle
of its length to a vertical bar U, the ends of which are fixed to the framing of
the door. The pivots T of the pieces B, being nearer the outer end than the inner
end thereof, the latter consequently bear with a proportionate amount of their
weight upon the inclined surfaces of C C¹
The pieces B may either be entirely of carbon or the greater part thereof may
be of metal, and only the part that rests on CC' may be of carbon, or again, the
whole may be of metal.
As the electric current of the battery passes from the support V to the piece B
through the pivot T, these two pieces might be connected together by a length of
helical wire for insuring proper connection without interfering with the piece B.
The electrical communications with the inducing circuits of the induction
bobbin I are arranged as shewn in the diagram Fig. 4. The pieces C and C₁
each communicate with one of the two inducing circuits with reversed currents.
The piece B communicates with one of the poles of the battery; the other pole
communicates with the two other ends of the inducing circuits. The induced coil
is not shewn at Fig. 4.
In place of a single bobbin two may be employed, in which case only a
single inducing coil is employed; it will then only be necessary to suitably
arrange the induced circuits of the two bobbins, either in quantity or in tension.
The advantage of this transmitter consists in its exceedingly simple con-
struction; it gives great effects with a single battery element, or with a current
from a small magneto machine.
The second carbon contact B is electrically connected to the one connected to
he battery circuit by a wire f connecting the two supports U U together.
Instead of two contact pieces only one might be employed, or several sets of
contacts C C B might be attached to different parts of the tympan M.
When speaking into a powerful telephonic transmitter, the currents of the line,
n passing through the local receiver, actuate the same and produce the effect as

page_text: though the speaker were speaking into his ear, which unpleasantly disturbs the
conversation.
In order to prevent this there are arranged locally secondary circuits as shewn
in the diagram Fig. 5 (the inducing circuit is not shewn here) I is the induction
coil, which has two induced circuits L and N; H is the local telephonic receiver 5
the bobbins of which also have two distinct circuits. The circuit L is connected
to one of the induced circuits of the induction coil, through one of the coils of the
receiver and thence into the line. It is consequently an ordinary circuit like all
the circuits of telephonic stations.
The circuit N is composed of the second induced circuit of the induction coil
and of the second coil of the receivers; it remains local and does not communicate
with the line.
The direction of the currents which pass through this circuit is the reverse of
that of the line current.
From this arrangement it will be readily understood that when speaking, the
two currents will neutralize each other in the local receiver and consequently the
before mentioned inconvenience cannot arise, while when listening to the specch
transmitted from the distant station, the action of the apparatus will be as
usual.
t
Instead of the arrangement at Fig. 5, which is the best, the neutralizing current
can be formed in a special induction coil the induced current of which is sent into
the local receiver.
In this case the primary current of the transmitter also passes through the
inducing coil of such supplemental instrument.
Or instead of having a second winding on a single induction coil, a shunt circuit
from the single winding may be used as the neutralising current for the receiver,
and it may be connected in the opposite direction to the terminals of the ordinary.
coil instead of providing a second coil.
In very hot climates the liquids of the batteries, in evaporating rapidly, cause
considerable inconvenience and trouble in maintaining the batteries in proper
order.
"
In order to avoid this inconvenience, and also for other purposes, the batteries
may be replaced by small magneto electric machines, commonly called "magnetos
such as are used for call bells. For this purpose there is introduced into the
revolving armature of the magneto, firstly the ordinary induced circuit which
serves for producing the currents for the call bell, and secondly another circuit of
about one Ohm resistance. This second circuit will serve to replace the battery
of the transmitter of the telephonic station. The currents from each circuit are
collected by a separate set of brushes.
The ordinary commutator with automatically acting hook is arranged to close
the circuit, for the calling current and to break the transmitter circuit when the
telephonic receiver is hooked on. When this is unhooked, the commutator will
break the call circuit and will close the transmitter circuit. Of course it is
in this case to turn the handle all the time one is speaking.
necessary
The simplicity of this arrangement will enable it to be understood without any
explanatory drawing being necessary.
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. In telephonic transmitters, the combination with the vibrating tympan of
two pieces of carbon such as CC, presenting between them a V-shaped opening
in which rests one or more carbon or other conducting contact pieces substantially
as described.
2. In telephonic apparatus, producing a neutralising current for the local
receiving instrument by locally transmitting to the bobbins of the local receiver a
current the reverse of that passing through the same from the line, whereby the

page_text: action of such current is neutralised when speaking into the local transmitter, sub-
stantially as and for the purposes described.
3. Producing the neutralizing current referred to in the preceding claim, by
means of a second separate induced coil in the induction bobbin, placed by the
side of the ordinary coil from which the line current issues, such second coil being
connected to a second reversing coil on the bobbins of the local receiving
instrument, substantially as described.
4. Producing the neutralizing current referred to in the second claim, by means
of an additional induction bobbin, into the primary coil of which is passed
the primary current of the transmitter while the current of the secondary coil
is connected to a second coil in the receiver bobbins, substantially as described.
5. Producing the neutralizing current referred to in the second claim by means
of a shunt circuit on the transmitter circuit, which is either connected to a second
coil on the receiver bobbins, or is connected to the terminals of the ordinary coil,
substantially as described.
Dated this 19th day of January 1892
ABEL & IMRAY,
Agents for the Applicant.