Improvements in Electric Telephonic Apparatus.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Telephonic Apparatus.
We HERBERT LUZERNE TODD of 19 Fifteen I Street Washington District of
Columbia United States of America Gentleman WILBUR FISK MELBOURNE of
20 Thirteen R Street Washington aforesaid Gentleman JAMES THOMPSON of 112
Frankland Street New York City in the United States of America Merchant and
RANULPH EDWARD MONTAGUE MOSTYN of 7 Cadogan Square in the County of
Middlesex Lieutenant Royal Artillery do hereby declare the nature of this invention
and in what manner the same is to be performed to he particularly described and
ascertained in and by the following statement :-
This Invention relates to improvements in electric telephonic apparatus and the
objects of the said invention are mainly to provide transmitting and receiving
apparatus by which articulate speech of any pitch can be transmitted and received
over great distances more distinctly correctly and loudly than heretofore. According
to this invention there is employed two or more separate coils of insulated wire in
conjunction with the diaphragm of the transmitter or of the receiver or both and
there is also an improved arrangement of switch cut out and push button by which
the bells and instruments are cut out of or put into circuit as desired.
In the transmitter the diaphragm is secured centrally so as to leave the periphery
free to vibrate and behind the said diaphragm are the aforesaid coils of insulated wire
the opposite ends of the wires of the said coils being both or all connected to the
battery and the line respectively. Electrodes are also arranged in combination with
the diaphragm as hereinafter described. There may also be additional coils in the
line to strengthen the current as hereinafter explained. We will describe the Invention
more particularly with reference to the accompanying drawings.
Figure 1 is a front elevation and Figure 2 is a section of an arrangement or
construction of the transmitting apparatus according to this Invention and Figure 3
is a section of a modification of the said transmitting apparatus and Figure 3ª is a
back view of the diaphragm thereof. Figure 4 is a section of the coils forming in
use the magnet. Figure 5 shews cross sections of suitable forms of the electrodes.
Figure 6 is a sectional view of the improved receiver. Figure 7 shews the arrange-
ment of the switch cut out line wires bells and push button. Figure 8 is a detail
view of the switch on which the receiver is hung and its appurtenances and
Figure 9 shows coils such as may be placed in connection with the line wire as
a relay.
A Figures 1 and 2 represents a disc or plate of circular or other convenient shape
and preferably of carbon although it may be made of any other suitable material.
This disc or plate forms the acoustic diaphragm of the transmitter and is secured
centrally to the core B. In close proximity to this diaphragm is the series of coils ff
of insulated wire constituting a compound coil C and forming the magnet. Five
such coils are shewn in the Drawing but there may be two or more as desired. The
wires of the coil Care of such cross section that they collectively equal the cross
section of the line and they are wound upon a bobbin h (or bobbins of insulating
material carried by a central core of soft iron) the ends F of such wires being all
connected to the wire f from the battery and the opposite ends F of the said wires
are all connected to the core B by the wire and so to the diaphragm and through
the electrodes D to the line wire. The said electrodes D (of which there may be one
or more) are suspended on a conducting wire or rod c supported in the brackets e.
The said electrodes may be of various shapes such for examplo as those shewn in
Figure 5 and they rest on the diaphragm at or near its edge. The apparatus is by
preference enclosed in a case E provided with a mouth piece a for speaking into. The
receiver Figure 6 consists of a case F composed of rubber, celluloid or any other
suitable insulating material enclosing a core of soft iron G one end of which is

page_text: surrounded by coils ff forming a compound coil similarly to those in the transmitter.
In front of the coil and in close proximity with the soft iron core of the receiver is a
diaphragm A secured in the case F2 (by the cap F³ with the orifice a' for the ear of
the user) so as to be held at its periphery. A cushion f of soft rubber or the like
may be used for it to bed against for allowing it greater amplitude of vibration. One
of the ends of each of the wires ff connected to the battery and all the opposite
ends are connected to the line wire. The vibrations are imparted from the diaphragm
of the transmitter through the line and are reproduced at the diaphragm of the
receiver the compound coil serving to increase the strength of the currents. Figure 3
represents a modified form of the transmitting apparatus consisting of diaphragm A
preferably of carbon. It is centrally connected to the core B which is turned with a
shoulder as at band on the said core is mounted the spool h of india rubber or other
insulating material. The outer end of the core is turned to a smaller diameter than
the main portion thereof and this reduced part is surrounded by a sleeve or ring of
rubber or other like material the outer circumference of which is greater than the
larger circumference of the core B and fits snugly to the opening of the carbon
ring d. Fastened to the diaphragm A at or near the periphery thereof are any
desired number of electrodes D which are so set that the inner ends are in close
proximity but normally do not touch the carbon ring d. The ends of the wires f
are all connected to the battery wire and the opposite ends F of all the said wires
are connected to the rear end of the core B and the wire or wires g from the carbon
ring d are connected to the line wire. The vibration of the diaphragm A causes
the electrodes D to touch the carbon ring d at each vibration thus completing the
circuit.
In connection with the transmitter receiver and bell I employ a switch cut out and
push button as illustrated in Figure 7 which is a diagram illustrating the general
arrangement at each station two stations A and B being shown.
EE are the transmitters, F F the receivers and K K² the switches acted on by
the receiver being hung in place to complete or removed to break the short circuit to
the bells. LL are push buttons of the double kind. Y Y are the batteries connected
by the wires 1, 33, and 18, 36 with the transmitters and line. 22, 23, 24 and 6, 7, 8,
are the short circuits for the bells which circuits are completed when the receivers
are on the hooks K K by the springs 22 and 6 being pressed by the inner arm
thereof against pins which are secured to the case and connected with the bell
circuit. When the receivers are removed the bell circuits are broken by the springs 22
and 6 leaving the pins 7 and pressing down the inner arm of the books K K² an
operation which the springs are sufficiently powerful to perform in the absence of the
receivers from the outer arm of the hooks as aforesaid.
When it is desired to signal a message say, for example, from station A to
station B the push button L is depressed as shown and being connected with the
battery Y in the instrument, will ring the bell of the instrument at the station B
by the current passing through the wires 1, 2, 3, 4, 5, 6, 7, to the bell of the
opposite instrument said bell being connected with the line wire by the wire 8
thereby avoiding a current through the coils in the transmitter and receiver at
station B and therefore giving the full strength of the battery to the bell. Before
the push button is used the hook K Figure 7 upon which the receiver hangs should
have been released by its removal making a connection for the return current from
the bell through the wires 9, 10 piece 11, hook arm 12 and piece 13 and thence to
the battery by 14, 15, 16 and 17. While the receiver hangs upon the hook as at K²
the hook is pressed downward and away from the pieces 11 and 12 and the inner end
of said hook being insulated by rubber or other suitable material, presses against the
spring 22 making a direct connection with the bell of that instrument. In order to
ring the bell in the opposite instrument, the receiver must be hanging upon the hook
of that instrument. When both instruments are released by the removal of the
receivers, the bells are cut out of the circuit and the transmitter and receiver are in
the line and ready for action the current then traversing the wires as follows:-com-
mencing at battery Y through 1, 33, transmitter E 34, 4, 5, 25, piece 26 hook arm 27,

page_text: piece 28, 29, to and through the receiver F by 38, on by 32 to battery Y2 and thence
by 18, 36 transmitter E, lines 35, 21, 9, 10, piece 11, hook 12, piece 13, 14 to and
through receiver F by 37 thence by 17, back to battery Y all other circuits being cut
out by reason that both buttons L L are in their normal position as shown with
reference to button LP Figure 7 and thus maintain their circuits open.
In the bells I prefer to use two multiple coils similar to those in the transmitter and
receiver instead of the ordinary single coil. Figure 9 shows the relay which consists
of coils ff on a core B all the one ends of the wires being connected to line and the
other ends of the said wires being connected by the wire to the core B and thence
by the wire to line.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1st. In telephone transmitters the combination of an acoustic diaphragm secured
centrally and one or more resistance varying electrodes so placed that they bear
lightly against said diaphragm as set forth.
2nd. In a telephone transmitter the combination of an acoustic diaphragm secured
centrally and one or more resistance varying electrodes with a multiple coil forming
the magnet when in use and consisting of a spool having a series of coils of insulated
wire wound upon it the opposite ends of said coils being connected as herein before
set forth.
3rd. In a telephone transmitter two or more coils connected with the line in
combination with a carbon diaphragm substantially as herein before set forth.
4th. In a telephone transmitter or receiver two or more coils connected with the line
in combination with a diaphragm substantially as hereinbefore set forth.
5th. The arrangement and combination of parts constituting a transmitting
apparatus, a receiving apparatus and a telephone line all substantially as herein
described.
6th. In a telephone the combination with transmitting and receiving apparatus of a
switch, cut out and a push button in connection with a telephone line all constructed
and arranged as shown and for the purpose herein specified.
7th. In combination with a telephonic apparatus the use of an additional coil, placed
in connection with the line wire near the receiving apparatus as described.
Dated this 30th day of October 1889.
J. H. JOHNSON & Co.,
Agents.