IMPROVEMENTS IN AND RELATING TO TELEPHONIC APPARATUS
Year: 1880

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN AND RELATING TO TELEPHONIC APPARATUS." A com-
- munication from abroad by Charles Adains Randall, of the City and State of
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 30th November 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO
[A communication from abroad by Charles Adams
Randall, of the City and State of New York, United States of America,
Electrician.]
TELEPHONIC APPARATUS."
This Invention relates to that class of telephone systems in which a battery
current traverses the circuit of wires connecting the stations, and is qualified by
tension changing and current changing or breaking devices operated by the
vibrations of a transmitter diaphragm.
Its object is to utilize to a maximum degree the force of a line battery connected
with a receiving apparatus to cause an extended range of variation in the strength
of the current of the line battery in correspondence with the variations of the
transmitter diaphragm, and to consequently effect an increased amplitude and
force of vibration in the diaphragm of the receiver.
Heretofore in telephonic transmitters generally the pressure contact has been
so light and delicate even at the maximum pressure that it has been impossible, so
far as I am aware, to utilize the full force of a battery. In fact, a current directly
from a battery through a galvanometer that will show a deflection of the needle 60°
will scarcely show any deflection, never more than 2°, when passed through a
telephonic transmitter as now generally used, so that but a small proportion of the
electro-motive force of the battery is obtained, and consequently but little power
in the apparatus. To remedy this, an induction coil is commonly used, the telephone
transmitter being placed in the primary circuit and the receiver in the secondary

page_text: circuit, in which the induced current is more intense, but necessarily lacking in
quantity and limited in power, as the induction in the secondary corresponds to a
great degree to the power of the current in the primary circuit, which as explained
is always very slight.
The especial advantages consist in obtaining power at the transmitter to control
and operate a main line battery and the increased movement of the contact points
and consequent variation in pressure contact, said increased movement corre-
sponding to the vibrations of the diaphragm, but increased in amplitude, the
increased movement and power at the contact points permitting of the use of large
or small batteries, and the actual make and break of contact of the same when
desired, or the actual and positive change of contact from one pole of a battery to
contact with the opposite pole of the same or a different battery, or the
transmission of alternate, negative, and positive currents, as hereinafter fully
explained.
Being enabled to utilize the full force of a battery a receiver may be worked
when desired directly by the main line current, with increased power and conse-
quent clearness and loudness of tones, and also without interference from induction,
leakage, or the like, and much longer circuits can be worked with reliability as
well as underground wires, either in connection with the system of alternating
current or single current transmission.
My said Invention consists mainly in a telephone system in which by means
of a variable contact pole changing circuit closer operated by a diaphragm under
the influence of sound vibrations, electrical connection with a line wire is alternately
made and broken from opposite poles of a battery or batteries, the makes and
breaks of the circuit being attended by varying pressure between the contact
points of the circuit closer and battery currents, or impulses of alternately opposite
polarities and varying force are caused to pass over the line circuit in correspondence
to sound vibrations.
The said Invention comprises the combination with a telephonic transmitter
diaphragm, a battery and main circuit of intermediate devices operated by the
diaphragm for changing the polarity or direction of the currents passing from the
battery to the main circuit.
In the system now in general use, in which an undulatory electric current is
employed upon the circuit, great trouble is' experienced from induction from
adjacent wires, which in many cases renders correct transmission difficult, especially
upon long lines, and also enables persons controlling adjacent wires to over-
hear others.
By the employment of alternating battery currents upon the line wire the effects
of induction are to a great extent prevented, and the sounds produced by the
diaphragm of the receiving apparatus are caused to be clear, sharp, and distinct.
My said Invention also comprises the combination in a telephone system with
an electro magnet controlling the current of a line battery, and the diaphragm of a
transmitting instrument of intermediate devices, whereby the vibrations of the
diaphragm cause variations of the force with which the said electro-magnet acts in
its control of said line battery, and in causing the line battery current so controlled
to control an electro magnet governing a local circuit, which may include a receiving
telephone.
My said Invention further comprises the combination in a telephone system of a
main line, a transmitter arranged to make and break the circuit of said main line
by the vibrations of its diaphragm, or similar vibrator moving in response to sound
vibrations, a local circuit including a telephone receiver and a tension changer, and
an electro magnet in the main circuit arranged to control said tension changer.
It has heretofore been considered impossible to transmit articulate tones by
actual make and break of the circuit at the transmitting instrument, and all
telephones now in use are worked on the closed circuit principle with undulatory
currents. The comparatively small electro motive force that can be utilized in
undulatory currents, the extreme sensitiveness necessary in the instruments, the

page_text: delicacy of adjustments required, and the very limited length of the circuits that
can be worked efficiently, are serious disadvantages to telephonic communication,
and to overcome these disadvantages is the object of my Invention.
This object I have in a great degree accomplished by rendering possible the
actual make and break of the circuit in correspondence with the movements of
the primary vibrator of the transmitting instrument, thus utilizing almost the
entire electro motive force of the battery for operating the receiver, in which
therefore less delicate adjustments than heretofore are required; by enabling the
use of the batteries of great electro motive force; by working a main line receiving
instrument or receiver relay, by a direct battery current instead of an induced
current, and by operating the final or telephonic receiver by means of a local
circuit.
The operation of this portion of my improved system requires a circuit breaking
transmitter in a main line circuit with a receiving electro magnet which in turn
controls the telephonic receiver in a local circuit.
The transmitter is so constructed that the contact points may be adjusted very
close to each other without actual contact, and one or both of these contact points
should be slightly yielding, so that varying contact pressure may be had, and so
arranged as to be controlled by the vibrations of the diaphragm or other primary
vibrator, the effect of which vibrations I preferably magnify by connecting with
said vibrator the short arm of a lever having the end of its long arm arranged to
operate the contact points.
The receiving apparatus comprises an electro-magnet in the main circuit, having
its armature adjusted to rapidly respond to the variations and cessations of magnetic
influence, and connected with a tension changer in a local circuit, which circuit
also includes the telephonic receiver which may be of any well known and suitable
construction.
My said Invention further comprises the combination in a telephone system of a
main line conductor, a telephonic transmitting apparatus arranged to transmit over
said main line currents of alternately opposite polarities by the vibrations of its
diaphragm, an automatic pole changing tension changer in the main circuit with
said transmitting apparatus, and a local circuit, including a receiving telephone,
arranged to be controlled by the line currents, and to change the directions and
vary the tension of the electric current over said local circuit, all essentially as
hereinafter described.
Also the combination in a telephone system of a main line conductor, a
transmitting telephone arranged to transmit currents of alternately opposite
polarities, and connected with said main line an automatic tension-changer in
circuit with said transmitting telephone, and a local circuit, including a receiving
telephone, and arranged to vary the tension of the electric current over said local
circuit, all substantially as hereinafter more particularly described. The especial
object of this part of my Invention is to provide a receiving station apparatus
which will promptly respond to the alternations of direction of a line current, and
cause alternately opposite currents or impulses of varying force from a local
battery to actuate the receiver diaphragm for causing sound vibrations thereof.
My Invention also comprises a novel receiving telephone, comprising the com-
bination with a telephonic receiver diaphragm of a helix having a detached and
movable soft iron core connected with said diaphragm, and a continuously
polarized magnet arranged adjacent to said core, whereby when electric currents
of alternately opposite polarity are passed over said helix, its movable core will
be polarized successively in opposite directions, and alternate attractions and
repulsions will be set up between the soft iron core and the continuously polarized
magnet, the force of said attractions and repulsions being commensurate with the
electro motive force of the battery which may be employed to generate the
electrical currents passing over the helix.
The object of this part of my Invention is to provide a receiver which will
secure the most effective results of the operation of the system and apparatus for

page_text: telephonic transmission by which currents of alternately opposite direction are
caused to pass over the line wire in response to the vibrations of the transmitter
diaphragm.
It is well known that the extreme sensitiveness of the ordinary magnetic
telephonic receivers is one of the main obstacles to distinct and clear communication,
the slightest induction upon the line wire or other interference with the line
current causing an aberration of variation in the magnetism of the permanent
magnet as the current passes over the coil surrounding the pole of said magnet. In
overcoming this difficulty I construct the receiver in such manner that its diaphragm
is operated by the electro-motive force of battery currents of alternate opposite
polarity instead of by induction as heretofore.
In carrying the said Invention into practice the mouth-piece is attached to a
ring, against the rear inner margin of which is arranged a diaphragm having
its margin enfolded by an elastic india rubber washer, and pressed against
the ring by spring fingers projecting inwardly from the rear margin of said ring.
The mouth piece and diaphragm are supported by a standard near one side, and the
standard also carries a bracket, in which is fulcrummed a lever, from the short arm
of which an arm projects, and by means of an adjustable spring is caused to bear
against the centre of the rear surface of the diaphragm. The long arm of the lever
(which is about three times the length of the short arm) terminates in a small
head. On opposite sides of the head are arranged electric contact terminals of the
battery circuit. Each of these terminal devices is composed of an adjustable base
having an upward projecting spring plate, to which is secured a block formed
preferably of wood or other insulating material and provided with an
extending upward. To the inner face of the block is secured a plate of india
rubber or similar insulating material, from one side of which extends upward a
metallic leaf spring, carrying at its tip a carbon button, while from the other side
of said rubber plate extends upward a similar metallic leaf spring carrying at its
tip a platinum stud projecting toward the carbon button. The springs of both the
contact devices are connected with the line wire by wires, and the springs carrying
the platinum studs are connected by wires respectively with the opposite poles of
the battery, the centre of which by a wire is connected with the ground. Adjusting
screws carried by standards bear against the supports of the springs carrying the
carbons for regulating the pressure of the platinum studs upon said buttons when
the former are actuated by the lever. The head of the lever is always in contact
with the springs carrying the platinum studs, but is insulated therefrom.
arm
Any of the ordinary and well known receiving telephones may be used in
connection with my system and transmitter.
The apparatus as now described may be enclosed in a suitable case with the
mouth piece projecting through an aperture thereof.
In a modification of my Invention the mouth piece and diaphragm are supported
by a standard, and from the upper portion of the mouth-piece-case projects an arm
to which is pivoted the upper end of a lever, from which projects an arm in contact
with the diaphragm. The lower end of the lever is provided preferably with
insulating studs (if the lever is metal). In each of the line and battery contact
devices a rock-shaft journalled in suitable bearings has fixed thereto a block of hard
india rubber or other suitable insulating material, and from this block project
upward plates and springs carrying their carbon buttons and platinum studs
respectively.
Springs press against the plates and have their tension controlled by screws
passing respectively through standards. The connections between the line wire
and battery are made in the same manner as above described.
By means of the controlling screws it is obvious that the amount of pressure
between the platinum studs and carbon buttons under the action of the lever may
be regulated as the plates and their rock shafts are alternately oscillated by the
movement of the lever and the carbon buttons are brought into varying degrees of
contact pressure with the platinum studs on the springs.

page_text: I provide an induction coil preferably constructed for quantity in the primary
circuit of which is to be arranged a transmitter preferably constructed to send
alternate currents of different polarities, and which in the present apparatus I term
the primary transmitter. In the secondary circuit of the induction coil is included
an electro magnet which I term an auxiliary magnet, the armature lever of which
is in the present instance an elastic metallic arm having one end secured to a
metallic post and its other end in contact with a carbon button supported by a
metallic arm which is also preferably elastic. The armature lever or the arm may
however be rigid. There is an electro magnet, one of the coil terminals of which is
connected with the arm and the other with a screw post, from which a wire is
intended to lead to one pole of a local battery, the other pole of which should be
connected with another screw post from which a wire leads to the metallic post.
An armature lever of the last named magnet is constructed similarly to that of the
other electro magnet and has one end secured to a metallic post while the other
end carries metallic studs projecting in opposite directions and in contact
respectively with carbon buttons, the former of which is carried by an elastic
metallic arm secured to a metallic post from which a wire leads to a screw post to
be connected with one pole of a line battery, while the latter is carried by an elastic
metallic arm connected by a wire with a screw post to be connected with the
opposite pole of said line battery, the main line wire being connected with a post
which supports the last named armature lever. There is a post intended to be
connected with the ground and provided with projections carrying adjustable
contact Screws which are in contact with the metallic arms.
By this arrangement it will readily be perceived that an increased movement of
the armature levers successively over the movement of the diaphragm is obtained
as well as great increase in the force of movement, the same depending almost
entirely upon the size of the second electro magnet and the electro motive force of
the local battery from which it receives its energy; said magnet and battery will in
practice correspond approximately with an ordinary "Morse" sounder and its local
battery.
As the armature lever moves under the influence of its magnet it alternately
increases and decreases the pressure of the studs upon the carbon buttons
respectively decreasing the pressure upon one while increasing that upon the other,
it being understood that increase or decrease of pressure between two conductors in
contact are practically equivalent to the positive making and breaking of contact,
causing the current to flow freely from one to the other, and a slight contact
resulting in a practical cessation of the flow. It will therefore be understood that
while the variations of contact on the buttons alternate the currents, they also
vary the flow and strength of said currents, the contact being made gradually from
minimum to maximum. When the increased pressure of the armature lever is
such upon one of the carbons as to cause the current to flow from one pole of the
battery to the line it forces the arm carrying said button out of contact with its
contact screw carried by the post, so that the other arm alone will be in connection
with the ground, and thus a complete circuit is formed from the line battery to
the ground in one direction and to line in the other, and full force of said line
battery may then act upon a receiver at a distant station, and cause the diaphragm
of said receiver to have a force of movement and range of amplitude far exceeding
that of the transmitter diaphragm, the feeble action of which, under the influence
of sound vibrations can produce but slight pressure contacts at most and cause the
induction of but weak currents in the secondary circuit of the induction coil.
These weak currents I cause to control a local battery by the vigorous current of
which the devices are operated which vary the main line current, thus gaining
power progressively from the transmitter diaphragm to the final tension changing
devices.
It will be readily understood that by dispensing with one of the carbon buttons
with proper connections from the other with the lever, line battery, and ground

page_text: the circuit may be gradually opened and closed, or the circuit may be closed and
the electro-motive-force or tension of the current varied over the same by the
action of the electro magnet,' and always in unison with the vibrations of the
diaphragm of the primary transmitter.
I may dispense with the induction coil and place the primary transmitter
directly in the circuit with the auxiliary magnet or with the transmitting magnet,
and may also dispense with the auxiliary magnet, and arrange the transmitting
magnet directly in the secondary circuit of the induction coil, all of which may be
done without departing from the principle of my Invention, the main object of
which is to obtain electro-magnetic power acting in unison with a vibrating
diaphragm or its equivalent actuated by the air vibrations of articulate tones to
control a main line battery, including in its circuit a telephonic receiving apparatus.
The diaphragm frame is provided with a mouth piece and supported by a
standard. The diaphragm may be supported in the frame in any approved manner.
From the upper part of the frame a stud projects rearward, and has pivotted to its
outer end a pendant lever, from which an arm extends, and may be secured to the
diaphragm, and is preferably pivotted to the lever. A lever is connected by a
spring with an adjusting screw in the standard, and at its lower end the said lever
carries an elastic cushion, preferably of india rubber, which is in contact with the
upper portion of a leaf spring rising from the base and connected with a screw
post. From the face of the spring opposite that which is in contact with the
cushion projects a platinum stud toward a plumbago button, which is carried by a
leaf spring. The lower end of this leaf spring is firmly secured to an arm which
is pivotted and extends rearwardly. A screw passes through the arm and bears
upon the base, its office being to adjust the arm for a purpose which will presently
appear. The upper end of the last named spring bears against the tip of an
adjusting screw arranged in a bracket projecting from a standard. By adjusting
the arm up or down the tension with which this spring bears against the screw
may be regulated, and by means of said screw the position of the spring may be
adjusted so as to bring the plumbago button to the proper distance from the
platinum stud. By means of the adjusting screw and spring the lever is adjusted
to cause the arm to bear with proper pressure upon the diaphragm, and also to
cause the said lever to promptly resume its normal position after being thrown
rearward by the diaphragm where the arm is not attached to the said diaphragm.
The transmitting instrument which has now been described is connected with one
pole of a battery by means of a wire leading from a screw post and with the line
The circuit is
wire by means of a binding screw and socket in one of the arms.
from the battery to the leaf springs, thence to the plumbago button, when the
platinum stud is in contact therewith, and from said button over the other leaf
spring and arm to the line. In the receiving apparatus there is an electro-magnet
mounted on a base; its armature is carried by a metallic spring arm, attached at
one end to a metal post, and carrying at the other end a platinum stud, which bears
upon a plumbago button carried by a leaf spring projecting from a metal post,
which is connected by a wire with one pole of a local battery, which has its other
pole connected with one terminal of the telephone, the other terminal of which is
connected with the spring arm through its post. The circuit is from the battery
to the telephone over a wire, and from the telephone to the spring arm post over
the spring arm plumbago button leaf spring to the other post, and thence back to
the battery.
One terminal of the electro magnet leads to a screw post, with which the main
line is connected, and the other terminal leads to a screw post which is connected
with the ground.
There are various modifications that may be made, such as using an induction
coil at the receiver, the primary coil being in circuit with the battery, and a tension
changer, and the telephonic receiver in the secondary circuit, as well as other
changes, without departing from the spirit of my Invention:

page_text: In the receiving apparatus there is an electro magnet consisting of helices having
soft iron cores connected by a yoke and terminating at the opposite ends in poles
extending toward each other. A permanently polarized steel bar is pivotted to
the yoke, and forms the armature of the instrument. This armature has fixed to
its end a metal rod or plate, which at its outer end is provided with platina
studs projecting in opposite directions. From an arm supported by a standard
metallic springs extend downward, and carry at their lower ends respectively
carbon buttons, which normally are lightly in contact with the platina studs. The
upper ends of the springs are secured to insulated studs projecting from the arm,
and said springs are respectively connected with wires which lead to the opposite
poles of a battery. From the middle of this battery a wire leads to one of the
binding posts of the telephonic receiver, and from the other binding post of said
receiver a wire leads to and is connected with the pivotted end of a polarized stee!
armature. One terminal of the helices of the polarized relay leads to the ground,
and the other is connected to the line wire, which at the transmitter is connected
with the branch wires which are respectively connected with contact springs of the
transmitter. These springs carry at their upper ends carbon buttons. Their lower
ends are secured to blocks of insulating material, preferably hard india rubber,
which are pivotted by means of suitable screws to plates projecting from the base
of the transmitter. To the inner sides of the block are secured light leaf springs,
having at their upper ends platina studs arranged opposite to, but separated from
the carbon buttons. The transmitter mouth piece is supported by a standard.
From the upper portion of the mouth piece there projects an arm, to which is
pivotted a downwardly extending lever, having at its lower end studs projecting
in opposite directions between leaf springs, and in contact therewith. From the
lever an arm extends to the diaphragm of the transmitter, and is pressed lightly
against the same by a spring attached to an adjusting screw arranged in the
standard. The lower ends of the two last named springs are connected to wires
which lead to opposite poles of a battery, from the middle of which a wire leads to
the ground. Adjusting screws are arranged in the standards respectively, and
carry on their inner portions suitable springs which bear against other springs, and
permit the same to yield.
My improved receiving telephone is constructed as follows, that is to say :-I
provide a tubular flanged case provided with a flaring ear piece in an ordinary
manner, and there is a non-magnetic diaphragm dampened by means of an india
rubber ring embracing its edge. Said diaphragm is provided with a centrally
projecting stud of soft iron or other magnetizable substance which serves as a
movable core for a fixed helix, the terminals of which are connected respectively
with screw posts at the end of the tubular case. One of these screw posts is
intended to be connected with the line wire, and the other with the ground.
Within the main portion of the tubular case and behind the helix is arranged an
electro magnet, the terminals of which are connected with screw posts respectively,
and these screw posts are to be connected with the opposite poles of a local battery.
The magnet is adjustable to and from the helix and its core by means of a screw
rod attached to the core of said magnet, and passing through the head of the case,
where a suitable adjusting nut is screwed upon it, and a spring surrounding said
rod and bearing against the helix and the inner surface of the head of the case.
The local electro-magnet is continuously polarized by the local battery current, and
as alternately positive and negative currents are sent over the line wire and the
helix by my improved transmitter, the polarity of the movable core is reversed so
that it is alternately attracted and repelled by the local magnet, thus causing the
diaphragm of the receiver to vibrate in correspondence with the electric impulses
over the line.
In lieu of the continuously polarized local electro magnet a permanent steel
magnet may be used if found desirable.
In this receiver it will be observed that the diaphragm is operated by the electro
motive force of the line battery rather than by simple induction as heretofore, and

page_text: therefore much more vigorous vibrations are produced, and the receiver magnet is
much less liable to be disturbed by induction.
In a modification the diaphragm is mounted in a similar case, and there are two
permanent steel magnets arranged longitudinally within the tubular portion of the
casing, with similar poles toward each other. A coil or helix of wire is arranged in
an axial position between the two magnets, and is separated therefrom by india
rubber washers. This helix is provided with a freely movable soft iron core, to one
end of which is secured a light rod of wood or metal, which passes through a
central passage of one of the magnets, and terminates in a head which is in contact
with an elastic pad in contact with or attached to the diaphragm. The terminals
of the helix are respectively connected with screw posts at the end of the case,
and when the receiver is in use one of these screw posts is to be connected with the
line wire and the other with the ground.
When the alternating battery current transmitter is in operation at the other end
of the line wire and currents of alternate opposite polarity pass over the line wire
and helix, the core is polarized in alternately opposite directions, and is therefore
attracted by the magnets alternately, its movements communicating vibrations to
the diaphragm through the rod and elastic pad, the rapidity of these vibrations
depending on the rapidity of the alternations of the currents over the line wire and
their force depending on the strength of the line currents and consequent
magnetism in the movable core.
It will be well understood that in lieu of the permanent magnets an electro
magnet properly wound and constantly charged by means of a battery may be
used, the helix and movable core being arranged between the ends of said electro-
magnet.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William. Robert Lake in the Great Seal Patent Office on the
30th May 1881.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO
A communication from abroad by Charles Adams
Randall, of the City and State of New York, United States of America,
Electrician.
TELEPHONIC APPARATUS."
This Invention relates to that class of telephone systems in which a battery
current traverses the circuit of wires connecting the stations, and is qualified by
tension changing and current changing or breaking devices operated by the
vibrations of a transmitter diaphragm.
Its object is to utilize to a maximum degree the force of a line battery connected
with a receiving apparatus to cause an extended range of variation in the strength
of the current of the line battery in correspondence with the variations of the
transmitter diaphragin, and to consequently effect an increased amplitude and force
of vibration in the diaphragm of the receiver.
Heretofore in telephonic transmitters the pressure contact has generally been so
light and delicate even at the maximum pressure that it has been impossible so far
as I am aware to utilize the full force of a battery. In fact it is found that a
current directly from a battery through a galvanometer that will show a deflection
of the needle 60° will scarcely show any deflection, never more than 2° when passed
through a telephonic transmitter as now generally used, so that but a small
proportion of the electro-motive force of the battery is obtained, and consequently
but little power in the apparatus. To remedy this an induction coil is commonly
used, the telephone transmitter being placed in the primary circuit, and the
receiver in the secondary circuit, in which the induced current is more intense but
necessarily lacking in quantity and limited in power, as the induction in the
secondary circuit corresponds to a great degree to the power of the current in the
primary circuit which as explained is always very slight.
The especial advantages consist in obtaining power at the transmitter to control
and operate a main line battery and the increased movement of the contact points
and consequent variation in pressure contact, said increased movement corresponding
to the vibrations of the diaphragm, but increased in amplitude, the increased
movement and power at the contact points permitting of the use of large or small
batteries, and the actual make and break of contact of the same when desired, or
the actual and positive change of contact from one pole of a battery to contact with
the opposite pole of the same or a different battery, or the transmission of alternate
negative and positive currents as hereinafter fully explained.
Being enabled to utilize the full force of a battery a receiver may be worked
when desired directly by the main line current with increased power, and
consequent clearness and loudness of tones, and also without interference from
induction, leakage, or the like, and much longer circuits can be worked with
reliability, as well as underground wires, either in connection with the system of
alternating current or single current transmission.
This Invention consists mainly in a telephone system, in which by means of a
variable contact pole changing circuit-closer operated by a diaphragm under the
influence of sound vibrations electrical connection with a line wire is alternately
made and broken from opposite poles of a battery or batteries, the makes and
breaks of the circuit being attended by varying pressure between the contact
points of the circuit-closer, and battery currents or impulses of alternately opposite

page_text: polarities and varying force are caused to pass over the line circuit in correspondence
to sound vibrations, as hereinafter described with reference to Figures 1, 2, and 3,
of the Drawing.
The said Invention comprises the combination with a telephonic transmitter-
diaphragm a battery and a main circuit of intermediate devices operated by the
said diaphragm for changing the polarity or direction of the currents passing from
the battery to the main circuit, as hereinafter described.
In the system now in general use in which an undulatory electric current is
employed upon the circuit, great trouble is experienced from induction from
adjacent wires, which in many cases renders correct transmission difficult, especially
upon long lines, and also enables persons controlling adjacent wires to overhear
others.
By the employment of alternating battery currents upon the line wire the effects
of induction are to a great extent prevented, and the sounds produced by the
diaphragm of the receiving apparatus are caused to be clear, sharp, and distinct.
The said Invention also comprises the combination in a telephone system with
an electro magnet controlling the current of a line battery, and the diaphragm of a
transmitting instrument of intermediate devices, whereby the vibrations of the
diaphragm cause variations of the force with which the said electro magnet acts in
its control of said line battery, and causing the line battery current so controlled to
control an electro magnet governing a local circuit, which may include a receiving
telephone, as hereinafter more particularly described, with reference to Figures 5
and 6 of the Drawing.
The said Invention further comprises the combination in a telephone system of a
main line, a transmitter arranged to make and break the circuit of the said main
line by the vibrations of its diaphragm or similar vibrator moving in response to
sound vibrations, a local circuit, including a telephone-receiver, and a tension
changer, and an electro-magnet in the main circuit, arranged to control the said
tension changer, as hereinafter more particularly described with reference to
Figure 7 of the Drawing.
It has heretofore been considered impossible to transmit articulate tones by
actual make and break of the circuit at the transmitting instrument, and all
telephones now in use are worked on the closed circuit principle, with undulatory
currents. The comparatively small electro-motive force that can be utilized in
undulatory currents, the extreme sensitiveness necessary in the instruments, the
delicacy of adjustments required, and the very limited length of the circuits that
can be worked efficiently, are serious disadvantages to telephonic communication,
and to overcome these disadvantages is the object of this Invention. This object I
have in a great degree accomplished by rendering possible the actual make and
break of the circuit in correspondence with the movements of the primary vibrator
of the transmitting instrument, thus utilizing almost the entire electro-motive
force of the battery for operating the receiver, in which therefore less delicate
adjustments than heretofore are required, by enabling the use of the batteries of
great electro motive force, by working a main line receiving instrument or receiver
relay, by a direct battery current instead of an induced current, and by operating
the final or telephonic receiver by means of a local circuit..
The operation of this portion of my improved system requires a circuit breaking
transmitter in a main line circuit, with a receiving electro magnet which in turn
controls the telephonic receiver in a local circuit. The transmitter is so constructed
that the contact points may be adjusted very close to each other without actual
contact, and one or both of these contact points should be slightly yielding so that
varying contact pressure may be had, and so arranged as to be controlled by the
vibrations of the diaphragm or other primary vibrator, the effect of which vibrations
I preferably magnify by connecting with the said vibrator the short arm of a
lever, having the end of its long arm arranged to operate the contact points.
The receiving apparatus comprises an electro magnet in the main circuit, having
its armature adjusted to rapidly respond to the variations and cessations of magnetic

page_text: influence, and connected with a tension-changer in a local circuit, which circuit
also includes the telephonic receiver that may be of any well known and suitable
construction.
The said Invention further comprises the combination in a telephone system, of a
main line conductor, a telephonic transmitting apparatus arranged to transmit over
the said main line currents of alternately opposite polarities by the vibrations of its
diaphragm an automatic pole changing tension-changer in the main circuit with
said transmitting apparatus and a local circuit including a receiving telephono
arranged to be controlled by the line currents, and to change the directions and
vary the tension of the electric current over the said local circuit, all essentially as
hereinafter described with reference to Figure 8 of the Drawing.
The said Invention further comprises the combination in a telephone system of
a main line conductor, a transmitting telephone arranged to transmit currents of
alternately opposite polarities, and connected with said main line an automatic
tension changer in circuit with the said transmitting telephone, and a local circuit
including a receiving telephone and arranged to vary the tension of the electric
current over the said local circuit, all substantially as hereinafter more particularly
described with reference to Figure 8. The especial object of this part of the said
Invention is to provide a receiving station apparatus which will promptly respond
to the alternations of direction of a line current, and cause alternately opposite
currents or impulses of varying force from a local battery to actuate the receiver
diaphragm for causing sound vibrations thereof.
My Invention also comprises a novel receiving telephone, comprising the com-
bination with a telephonic receiver diaphragm of a belix having a detached and
movable soft iron core connected with the said diaphragm and a continuously
polarized magnet arranged adjacent to the said core, whereby when electric currents
of alternately opposite polarity are passed over the said helix its movable core
will be polarized successively in opposite directions, and alternate attractions
and repulsions will be set up between the soft iron core and the continuously
polarized magnet, the force of the said attractions and repulsions being com-
mensurate with the electro motive force of the battery, which may be employed
to generate the electrical currents passing over the said helix.
The object of this part of my Invention is to provide a receiver which will
secure the most effective results of the operation of the system and apparatus for
telephonic transmission, by which currents of alternately opposite direction are
caused to pass over the line wire in response to the vibrations of the transmitter
diaphragm.
It is well known that the extreme sensitiveness of the ordinary magnetic
telephonic receivers is one of the main obstacles to distinct and clear communication,
the slightest induction upon the line wire or other interference with the line
current causing an aberration of variation in the magnetism of the permanent
magnet as the current passes over the coil surrounding the pole of the said magnet.
In overcoming this difficulty I construct the receiver in such a manner that its
diaphragm is operated by the electro-motive force of battery currents of alternate
opposite polarity instead of by induction as heretofore, as hereinafter more fully
described with reference to Figures 9 and 10 of the Drawing.
In the accompanying Drawing
Figure 1 is a perspective view of an alternating battery current telephonic
transmitter, and
Figure 2 is an elevation partly in section of the same.
Figure 3 is a side elevation partly in section of a modification of the said
apparatus.
Figure 4 is a detail view illustrating the construction of the contact devices of
the pole-changer.
Figure 5 is a side elevation, and
Figure 6, a plan or top view of another form of transmitting apparatus
constructed according to my Invention.

page_text: Figure 7 is a side elevation of a transmitter and a station receiving apparatus
constructed and connected according to my Invention.
Figure 8 illustrates in elevation another form of station receiving apparatus
connected by a line wire with an alternating current transmitter.
Figure 9 is a view partially in diametric section of a receiving telephone
constructed according to this Invention.
Figure 10 is a similar view of a modified form of the said receiving telephone.
A, in Figures 1, 2, 3, indicates the mouth piece, and B its diaphragm. This
mouth-piece is attached to the ring C, against the rear inner margin of which
is arranged the diaphragm having its margin enfolded by an elastic india-
rubber washer D, and pressed against the ring C by spring fingers d projecting
inwardly from the rear margin of the said ring. The mouth piece and
diaphragm are supported by a standard E near one side, and the standard
also carries a bracket f, in which is fulcrumed a lever G, from the short
arm g of which an arm h projects, and by means of an adjustable spring i is
caused to bear against the centre of the rear surface of the diaphragm. The
long arm g of the lever (which is about three times the length of the short arm)
terminates in a small head k. On opposite sides of this head k are arranged
the electric contact terminals L and L of the battery circuit. Each of these
terminal devices is composed of an adjustable base m, having an upward projecting
spring plate m³, to which is secured a block n, formed preferably of wood or other
insulating material, and provided with an arm extending upward. To the inner
face of the block n is secured a plate O of india-rubber or similar insulating
material, from one side of which extends upward a metallic leaf spring p, carrying
at its tip a carbon button p¹, while from the other side of the said india-rubber
plate extends upward a similar metallic leaf spring 9, carrying at its tip a platinum
stud q' projecting toward the carbon button p¹. The springs p of both the contact
devices are connected with the line wire R by wires r, and the springs q carrying
the platinum studs q¹ are connected by wires s, s¹, respectively with the opposite
poles of the battery, the centre of which by a wire 82 is connected with the ground.
Adjusting screws t, t, carried by standards T, T, bear against the supports of the
springs carrying the carbon buttons p¹ for regulating the pressure of the platinum
studs upon the said buttons when the former are actuated by the lever G. The
head of this lever G is arranged to be in contact with the springs q, but is insulated
therefrom.
In operating the transmitter, the person transmitting speaks in front of the
diaphragm in the usual manner, and as the diaphragm vibrates in response to air
vibrations produced by the voice, the lever G is caused to oscillate by means of
the arm bearing on the diaphragm. The movements of the lower end of the
lever force first one platinum stud q¹ and then the other stud into contact with its
adjacent carbon button p², and as the said platinum stud strikes the carbon buttons
electric connection of the line wire R is made with one or the other pole of the
battery, as the case may be, and such connections are made with the respective
battery poles alternately in correspondence with the vibrations of the diaphragm
as long as the speaking continues, and alternately positive and negative currents
flow over the said line wire to the receiving apparatus at the other end or at the
station in communication, and the tension of these alternate currents is qualified or
varied in correspondence to the amplitude of the vibrations of the diaphragm,
which, as they cause greater or less movement of lever G, produce greater or less
pressure of contact between the platinum studs q' and carbon buttons p¹, the
greater the vibration of the diaphragm, and consequent movement of the lever G,
the greater the pressure of contact between the platinum studs and the carbon
buttons, and vice versa, the resultant modulations of the receiver being in accordance
with theories too well established to require explanation here.
. Any of the ordinary and well known receiving telephones may be used in
connection with my system, and the transmitter herein described. .

page_text: The apparatus above described may be enclosed in a suitable case with the
mouth-piece projecting through an aperture thereof.
In the modification of my Invention shown in Figure 3 the mouth piece and
diaphragm are supported by a standard A', and from the upper portion of the said
mouth-piece case projects an arm a to which is pivotted the upper end of a
lever G¹, from which projects an arm a¹ in contact with the diaphragm at D'.
The lower end of this lever is preferably provided with insulating studs (if the
lever is metal). In each of the line and battery contact devices a rock shaft u
journalled in suitable bearings has fixed thereto a block of hard india rubber or
other insulating material, and from this block project upward the plates p² and
springs q², which respectively carry the carbon buttons p³ and platinum studs q³.
Springs 2,2, press against the plates p² and have their tension controlled by
screws ww, passing through the standards A' and A². The connections between
the line wire and the battery are made in the same manner as that shown and
described with reference to Figures 1 and 2.
ข
By means of the screws w, w¹, it is obvious that the amount of pressure between
the platinum studs q³ and carbon buttons 23 under the action of the lever G may
be regulated, as the plates p² and their rock shafts are alternately oscillated by the
movement of the lever G₁, and the carbon buttons p³ are brought into varying
degrees of contact pressure with the platinum studs q" on the springs q².
Referring now to the form of transmitter shown in Figures 5 and 6, A in the
said Figures designates an induction coil (preferably constructed for quantity) in
the primary circuit of which is to be arranged a transmitter, preferably constructed
to send alternate currents of different polarities, and which in the present apparatus
I term the primary transmitter. In the secondary circuit of the induction coil is
included an electro magnet B, which I term an auxiliary magnet, the armature
lever b of which is in the present instance an elastic metallic arm, having one end
secured to the metallic post 6', and its other end in contact with a carbon button B₁
supported by a metallic arm 6", which is also preferably elastic. The lever b or
the arm 6 may however be rigid. C indicates an electro-magnet, one of the coil
terminals of which is connected with the arm 611, and the other with a screw post d,
from which a wire extends to one pole of a local battery, as indicated in dotted lines
in Figure 6; the other pole of the battery should be connected with a screw-post d',
from which a wire leads to the post 6. The armature lever c of the magnet C is
constructed similarly to that of the magnet B, and has one end secured to a
metallic post c', while the other end carries metallic studs e, e¹, projecting in
opposite directions, and in contact respectively with carbon buttons F, F', the
former of which is carried by an elastic metallic arm f secured to a metallic post f¹.
From this post a wire f2 extends to a screw-post g connected with one pole of a
line battery, as also shown in dotted lines in Figure 6. The button F¹ is carried
by an elastic metallic arm h connected by a wire h¹ with a screw post g' connected
with the opposite pole of the said line battery, the main line wire I being connected
with the post c', which supports the armature lever c. The post K is connected
with the ground, and is provided with projections carrying adjustable contact
screws k, k, which are in contact with the arms f and h.
The operation of this apparatus is as follows, that is to say:-
The tension of the current on the primary circuit of the induction-coil A being
varied by the action of the transmitter-diaphragm in a well-known manner
corresponding variations occur in the induced current of the secondary circuit, and
as the secondary circuit actuates the magnet B the impulses of the said magnet will
always be in unison both as to frequency and force with the vibrations of the
transmitting diaphragm, and therefore the armature lever b is caused to vary the
pressure contact between itself and the carbon button B', so that the flow of the
local battery current which energizes the magnet C will also be varied, and said
magnet C will act upon its armature with varying force and also in correspondence
with the vibrations of the transmitter-diaphragm. By this arrangement it will
readily be perceived that an increased movement of the armature levers successively

page_text: over the movement of the diaphragm is obtained, as well as great increase in the
force of movement, the same, depending almost entirely upon the size of the
electro magnet C and the electro-motive force of the local battery from which it
receives its energy. The said magnet and battery will in practice correspond
approximately with an ordinary "Morse" sounder and its local battery.
As the armature lever c moves under the influence of its movement it alternately
increases and decreases the pressure of the studs e, e', upon the carbon buttons F, F¹,
decreasing the pressure upon one while increasing that upon the other, it being
understood that increase or decrease of pressure between two conductors in contact
is practically equivalent to the positive making and breaking of contact, causing
the current to flow freely from one to the other, and a slight contact resulting in a
practical cessation of the flow. It will therefore be understood that while the
variations of contact on the buttons F, F¹, alternate the currents they also vary the
flow and strength of said currents, the contact being made gradually from minimum
to maximum. When the increased pressure of the lever c is such upon one of the
carbons as to cause the current to flow from one pole of the battery to the line it
forces the arm carrying the said button out of contact with its contact-screw
carried by the post K so that the other arm alone will be in connection with the
ground, and thus a complete circuit is formed from the line battery to the ground
in one direction and to line in the other, and full force of said line battery may
then act upon a receiver at a distant station and cause the diaphragm of the said
receiver to have a force of movement and range of amplitude far exceeding that of
the transmitter-diaphragm, the feeble action of which under the influence of sound
vibrations can produce but slight pressure contacts at most and cause the induction
of but weak currents in the secondary circuit of the induction-coil. These weak
currents I cause to control a local battery, by the vigorous current of which the
devices are operated, which vary the main line current, thus gaining power
progressively from the transmitter-diaphragm to the final tension changing
devices.
It will be readily understood that by dispensing with one of the carbon buttons
with proper connections from the other with the lever, line, battery, and ground,
the circuit may be gradually opened and closed, or the circuit may be closed and
the electro-motive force or tension of the current varied over the same by the action
of the electro-magnet and always in unison with the vibrations of the diaphragm of
the primary transmitter.
I may dispense with the induction-coil and place the primary transmitter directly
in the circuit with the auxiliary magnet B or with the transmitting magnet C, and
may also dispense with the auxiliary magnet B¹ and arrange the transmitting
magnet C directly in the secondary circuit of the induction coil, all of which
modifications may be effected without departing from the principle of my
Invention, the main object of which is to obtain electro-magnetic power acting in
unison with a vibrating diaphragm or its equivalent actuated by the air vibrations
of articulate tones to control a main line battery including in its circuit a telephonic
receiving apparatus.
Referring now to Figure 7 A designates the diaphragm frame, provided with a
mouth-piece band supported by a standard c. The diaphragm, which may be
supported in the frame in any suitable manner, is indicated by the dotted line, as
at D. From the upper part of the frame A a stud e projects rearward, and has
pivoted to its outer end a pendent lever F, from which an arm g extends and
may be secured to the diaphragm, and is preferably pivoted to the lever. The
lever F is connected by a spring with an adjusting screw f¹ in the standard c,
and at its lower end the said lever carries an elastic cushion h preferably of india-
rubber, which is in contact with the upper portion of a leaf-spring I rising from
the base k, and connected with the screw-post 7. From the face of the spring I,
opposite that which is in contact with the cushion, a platinum stud m projects
toward a plumbago button N, which is carried by a leaf-spring O. The lower
end of this leaf spring O is firmly secured to the arm p, which is pivoted at p¹ and

page_text: extends rearwardly. A screw q passes through this arm p and was upon
base, its office being to adjust the arm for a purpose which will presently appear.
The upper end of the spring O bears against the tip of an adjusting screw
arranged in a bracket 1, projecting from a standard s. By adjusting the arm up
or down the tension with which this spring O bears against the screw r may be
regulated, and by means of the said screw r the position of the spring may be
adjusted so as to bring the plumbago button N to the proper distance from the
platinum stud m. By means of the adjusting screw f' and the spring f the lever F
is adjusted to cause the arm g to bear with proper pressure upon the diaphragm,
and also to cause the said lever to promptly resume its normal position after being
thrown rearward by the diaphragm where the arm g is not attached to the said
diaphragm. The transmitting instrument last above described is connected with
one pole of the battery B' by means of a wire leading from the screw-post 7, and
with the line wire L, by means of a binding screw and socket in the arm p. The
circuit is from the battery to the leaf-spring I, thence to the plumbago button N,
when the platinum stud is in contact therewith, and from the said button over the
spring and arm p to the line. In the receiving apparatus or receiver T
designates an electro-magnet mounted on a base t, and T is its armature carried
by a metallic spring arm U, attached at one end to a metal post U', and carrying
at the other end a platinum stud u which bears upon a plumbago button V carried
by a leaf spring v projecting from a metal post v₁; this post is connected by a
wire w with one pole of a local battery B2, which has its other pole connected with
one terminal of the telephone W, the other terminal of which is connected with
the spring arm U through the post U₁. The circuit is from the battery to the
telephone and from the telephone to the post U¹, over the spring arm U, the
plumbago button V, the leaf-spring v, the post v¹, and thence back to the battery.
One terminal of the electro-magnet T leads to a screw-post x with which the
main line L is connected, and the other terminal leads to a screw-post a¹ which is
connected with the ground.
The operation of this apparatus is as follows, that is to say:-Upon speaking into
the mouth-piece of the transmitting apparatus there is given to to the diaphragm
a to and fro movement, the effect of which is increased in force and amplitude at
the circuit-closer, viz., the plumbago button N and platinum stud m, by means of
the lever. These rapid to and fro movements alternately make and break the
circuit over the main line, and the currents in turn pass over and through the
receiving magnet T of the receiving apparatus, and cause a varying attraction of
its armature corresponding to the amplitude of the vibrations of the diaphragm,
said varying attraction and non attraction of the armature causing a varying
contact between the carbon button V and platinum stud u in the local circuit,
having the local battery and the telephonic receiver therein, so that the electrical
impulses over the telephonic receiver correspond in number and in varying power
to the vibrations of the diaphragm and the amplitude of its movements. There
are various modifications that may be made, such as using an induction coil at the
receiver, the primary coil being in circuit with the battery and a tension-changer,
and the telephonic receiver in the secondary circuit, as well as other changes
without departing from the spirit of my Invention.
In Figure 8 A designates the receiving apparatus; B, the transmitter (which has
been already described); and C the main line. In the receiving apparatus D, D,
represent an electro-magnet, consisting of the helices d, d, having soft iron cores
connected at one end by the yoke e, and terminating at their opposite ends in
poles ff, extending toward each other. A permanently polarized steel bar is
pivoted at g to the yoke e, and forms the armature of the instrument. This
armature has fixed to its end a metal rod or plate h, which at its outer end is
provided with platina studs i, i, projecting in opposite directions. From an arm k
supported by a standard K metallic springs 1, 1, extend downward and carry at
their lower ends carbon buttons m, m³, which normally are lightly in contact with
the platina studs i, i'. The upper ends of these springs 1, 11, are secured to

page_text: insulated studs n, n', projecting from the arm k, and the said springs are respec-
tively connected with wires o, o¹, which lead to the opposite poles of the battery P.
From the middle of this battery P a wire q' leads to one of the binding posts of
the telephonic receiver R, and from the other binding post of the said receiver
a wire q leads to and is connected with the pivoted end of the polarized steel
armature G. One terminal d¹ of the helices d of the polarized relay leads to the
ground, and the other is connected to the line wire C, which at the transmitter is
connected with the branch wires c, c', connected with the contact springs t, t¹, of
the transmitter. These springs carry at their upper ends carbon buttons u, u¹;
their lower ends are secured to blocks v, v, of insulating material, preferably hard
india-rubber, which are pivoted, by means of suitable screws, to plates v² projecting
from the base of the transmitter. To the inner sides of the blocks v, vl, are secured
light leaf springs w, w', having at their upper ends platina studs arranged opposite
to but separated from the carbon buttons u, u. F indicates the transmitter mouth-
piece supported by a standard F¹, the position of the diaphragm being indicated by
the dotted line x. From the upper portion of this mouth-piece projects an arm H¹
to which is pivoted a downwardly extending lever H having at its lower end
studs H2 projecting in opposite directions between the leaf-springs w, w¹, and in
contact therewith. From the lever H an arm I extends to the diaphragm of the
transmitter, and is pressed tightly against the same by a spring L attached to an
adjusting screw L' arranged in the standard F¹. The lower ends of the springs w, w',
are connected to wires which lead to opposite poles of a battery P¹, from the middle
of which a wire leads to the ground. Adjusting screws N, N₁, are arranged in the
standards F2 and F¹, and carry on their inner portions suitable springs which bear
against the springs t, t', and permit the same to yield. The operation of this system
and apparatus is as follows, that is to say:-The diaphragm of the transmitter
being caused to vibrate by sound, the vibrations of the said diaphragm cause to be
transmitted through the arm I a vibrating motion to the lever H, which moves the
light leaf springs w and w¹, causing the platina stud of first one and then the other
spring to come in contact with the carbon button opposite thereto, thus alternately
making electrical connection between the line C through the branches c, c', and
currents of opposite polarity flow over the line and through the helices d, d, of the
receiving apparatus A. The alternation of the current through the said helices
causes the polarized armature G to be attracted alternately by the poles f, f¹, and
this causes the platina studs i and i to press with greater and varying force upon
the carbon buttons m and m' alternately. When the pressure is greatest upon the
button m, for instance, a current flows from the battery P over the wire o, the
spring, the button m, the stud i, the rod h, the armature G, the wire q, through
the telephone R, over the wire q¹, and back to the battery; but when the pressure
is greatest upon the button m', the circuit is established from the other pole of the
battery through the wire o¹, the spring 1, the button m³, and thence back to the
battery through the telephone by the same route as before, currents of alternately
opposite polarity being thus caused to actuate the diaphragm of the receiver in
correspondence to the vibrations of the diaphragm of the transmitter. By dis-
pensing with one of the carbon buttons m or m², and its spring, and dispensing
with one of the wires o or o¹, and connecting the telephone wire q¹ to the opposite
pole of the battery from the remaining wire, the receiving apparatus may be
arranged to simply vary the tension of a current flowing in one direction through
the receiver, this variation of tension being caused by the greater or less force with
which the vibration of the armature G causes the rod h to press its platina stud
against the carbon button, alternately light and strong contacts being made
between the carbon button and platina stud, as the vibrations of the armature G
vary in force and direction in correspondence with the varying force of the main
line current through the helices d, and the polarity of the current transmitted. The
variations in the force of the main line current is caused by the variable contact
pressure between the carbon buttons u, u', and the platina studs of the
springs w, w', at the transmitter, this variable pressure contact resulting from the

page_text: variable force with which the lever H vibrates in response to sound vibrations
actuating the diaphragm of the transmitter. Referring now to my improved
receiving telephone illustrated in Figure 9, A indicates a tubular flanged case
provided with a flaring ear-piece in the ordinary manner, and B is a non-magnetic
diaphragm, dampened by means of an india rubber ring b embracing its edge. The
said diaphragm is provided with a centrally projecting stud C of soft iron or other
magnetizable substance which serves as a movable core for a fixed helix D, the
terminals of which are connected respectively with screw posts e, e¹, at the end of
the tubular case. One of these screw posts intended to be connected with the
line wire and the other with the ground. Within the main portion of the tubular
case and behind the helix D is arranged an electro-magnet F, the terminals of
which are connected with screw-posts g, g', and these screw-posts are connected with
the opposite poles of a local battery, as at H. The magnet F is adjustable to and from
the helix D and its core by means of a screw rod I attached to the core of the said
magnet and passing through the head of the case, where a suitable adjusting nut j
is screwed upon it, and a spring k surrounding the said rod and bearing against the
helix and the inner surface of the head of the case. The local electro magnet is
continuously polarized by the local.battery current, and as alternately positive and
negative currents are sent over the line wire and the helix D by my improved
transmitter the polarity of the movable core C is reversed, so that it is alternately
attracted and repelled by the local magnet, thus causing the diaphragm of the
receiver to vibrate in correspondence with the electric impulses over the line.
In lieu of the continuously polarized local electro magnet a permanent steel
magnet may be used if found desirable. In this receiver it will be observed that the
diaphragm is operated by the electro motive force of the line battery rather than
by simple induction as heretofore, and therefore much more vigorous vibrations are
produced and the receiver magnet is much less liable to be disturbed by induction.
In the modification shown in Figure 10, the diaphragm is mounted as shown in
Figure 9 and in a similar case. M, M, indicate two permanent steel magnets
arranged longitudinally within the tubular portion of the casing with similar
poles towards each other. A. coil or helix of wire O is arranged in an axial position
between these two magnets M, M¹, and is separated therefrom by india rubber
washers P, P.
This helix O is provided with a freely moveable soft iron
core O', to one end of which is secured a light rod Q of wood or metal,
which passes through a central passage of the magnet M', as shewn in
dotted lines, and terminates in a head r which is in contact with an elastic pad s
that touches or is attached to the diaphragm. The terminals of the helix O are
respectively connected with the screw-posts t, t¹, at the end of the case, and when
the receiver is in use one of these screw-posts is to be connected with the line wire,
and the other with the ground. When the alternating battery current transmitter
is in operation at the other end of the line wire, and currents of alternate opposite
polarity pass over the said line wire and helix O, the core O' is polarized in
alternately opposite directions, and is therefore attracted by the magnets M and M¹
alternately, its movements communicating vibrations to the diaphragm B through
the rod and elastic pad s, the rapidity of these vibrations depending on the
pidity of the alternations of the currents over the line wire, and their force
depending on the strength of the line currents and consequent magnetism in the
movable core.
It will be well, understood that in lieu of the permanent magnets an electro
magnet properly wound and constantly charged by means of a battery may be
used, the helix and movable core being arranged between the ends of the said
electro magnet.
↑
(
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
First. A telephone system in which by means of a variable contact pole
hanging circuit-closer operated by a diaphragm under the influence of sound

page_text: vibrations, electrical connection with a line wire is alternately made and broken
from opposite poles of a battery or batteries, the makes and breaks of the circuit
being attended by varying pressure between the contact points of the circuit
closer, and battery currents or impulses of alternately opposite polarities and
varying force are caused to pass over the line circuit in correspondence to sound
vibrations, substantially as above set forth and as illustrated in Figures 1, 2, 3, of
the Drawing.
Second. In a telephone system, the combination with a main line and a main
battery or batteries of a pole changing circuit-closer, a transmitting plate or
diaphragm and a suitable lever having a short arm connected with the said plate
or diaphragm, and a long arm arranged to act upon the said circuit closer, for
alternately making and breaking electrical connection between the line and ground,
and the opposite poles of one or more batteries with a varying contact corre-
sponding in force and frequency with the movements of the said lever and
diaphragm or plate under the influence of sound vibrations, substantially as
shewn in Figures 1, 2, 3, of the Drawing.
Third. A telephone system in which a lever is caused to vibrate or oscillate by
the transmitter diaphragm, and to come in contact alternately with the opposite
terminals or electrodes of a battery, with a pressure contact corresponding to the
amplitude of the vibrations of the said transmitter diaphragm, substantially as
herein described and as shewn in Figures 1, 2, 3, of the Drawing.
Fourth. The combination with the diaphragm of a transmitting telephone of the
lever G provided with a projection bearing against the said diaphragm, the carbon
buttons p, p, both adapted for connection with the line wire, and the springs q
adapted to be connected with the opposite poles of a battery, substantially as above
described.
Fifth. The combination with the lever operated by the diaphragm of the line
and battery contact devices, each composed of. a rocking insulating block carrying
on a suitable support a carbon button arranged for connection with the line wire,
and carrying also a platinum stud supported adjacent to the said carbon button,
and between it and the lever by a suitable spring, the said springs of the contact
devices being arranged respectively for connection with opposite poles of a battery
substantially as above described and as shewn in Figures 1, 2, 3, 4, of the
Drawing.
Sixth. In a telephone system the combination with an electro magnet controlling
the current of a line battery and the diaphragm of a transmitting instrument of
intermediate devices, whereby the vibrations of the diaphragm cause variations of
the force with which the said electro magnet acts, substantially as herein described
and as shewn in Figures 5 and 6 of the Drawing.
Seventh. The improved system of telephonic transmission herein described
consisting in causing the vibrations of a transmitter diaphragm or its equivalent
to control an electro magnet, which in turn controls the current of a local battery
through an electro-magnet arranged to control a main line battery, essentially as
shewn in Figures 5 and 6 of the Drawing.
Eighth. The combination in a telephone system of a main line, a transmitter
arranged to make and break the circuit of the said main line by the vibrations of
its diaphragm or similar vibrator moving in response to sound vibrations, a local
circuit, including a telephone receiver and a tension-changer, and an electro-magnet
in the main circuit arranged to control the said tension changer, substantially as
above set forth and as illustrated in Figure 7 of the Drawing.
Ninth. The combination in a telephone apparatus of the lever F arranged to be
operated by the vibrations of the diaphragm, the leaf spring I, the leaf spring O,
and suitable intermediate contact devices, the said springs being arranged to form
a portion of the main line when contact is made between them, substantially as
above described and as shewn in Figure 7 of the Drawing.
Tenth. The combination with the transmitter and main line of the local circuit,
including the telephone and the electro magnet T controlled by the main line, and

page_text: arranged to vary the pressure of contact between the contact points of the local
circuit closer, substantially as above described with reference to Figure 7 of the
Drawing and for the purpose specified.
Eleventh. The combination with the lever F operated by the vibrations of the
diaphragm, and the leaf spring operated by the said lever, of the spring O and
devices for adjusting the tension of the same, substantially as above described and
as shewn in Figure 7 of the Drawing.
Twelfth. The combination in a. telephone system of a main line conductor a
telephonic transmitting apparatus arranged to transmit over the said main line
currents of alternately opposite polarities, by the vibrations of the diaphragm, an
electro magnetic pole changing tension-changer in the main circuit with said trans-
mitting apparatus and a local circuit, including the receiving telephone, and
arranged to be controlled by the line currents and to change the direction and
vary the tension of the electric currents over the said local circuit, all substantially
as above described and as shewn in Figure 8 of the Drawing.
Thirteenth. The combination in a telephone system of a main line conductor, a
transmitting telephone arranged to transmit currents of alternately opposite'
polarities, and connected with the said main line, an electro magnetic tension-
changer in circuit with the said transmitting telephone and a local circuit, including
a receiving telephone, and arranged to be controlled by the line currents and to
vary the tension and force of the local currents over the receiving telephone,
substantially as above described and as illustrated in Figure 8 of the Drawing.
Fourteenth. In a telephonic receiver the combination with a diaphragm of a
helix having a detached and movable soft iron core connected with the said
diaphragm, and a continuously polarized magnet arranged adjacent to the said
core, whereby when electric currents of alternately opposite polarity are passed
over the said helix its movable core will be alternately attracted and repelled by
the said continuously polarized magnet, and thus communicate vibrations to the
diaphragm, substantially as above described and as shown in Figures 9 and 10 of
the Drawing.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Thirtieth day of May, in the year of our Lord One
thousand eight hundred and eighty-one.