Improvements in Telephone Transmitters.
Year: 1898

page_text: Date of Application, 22nd Mar., 1898-Accepted, 7th May, 1898
COMPLETE SPECIFICATION.
Improvements in Telephone Transmitters.
I, GEORGE FIEGLE PAYNE, of 656, North Twelfth Street, Philadelphia, in the
State of Pennsylvania, Philadelphia, U.S.A., Contractor, 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, and accompanying
drawing, that is to say :-
My invention relates to the construction of telephone transmitters, and has for
its object to increase the amplitude of the electrical undulations or vibrations produced
by the transmitter and, more especially, to produce electrical undulations which will
be in more perfect accord with the sonorous vibrations which actuate the transmitter
diaphragm than has heretofore been practical; with the result of producing a
transmitter capable of transmitting a telephonic current through great resistance and
impedance on the line. While in certain features my invention is advantageously
applicable to transmitters which are adapted to avail themselves only of a part of the
power of the battery or other generator used in connection with the primary
circuit, it is a special purpose of my invention to provide an arrangement of electrodes
in the transmitter which, in their action upon the electrical current, will operate in a
manner approximately similar to a pole changing switch having two movable portions,
and this special purpose I accomplish by providing four resistance cells containing
granular conducting material, electrically coupling said cells in pairs and connecting
the coupling conductors, then electrically coupling the cells in two other pairs, the
members of which are not coupled by the first conducting connections, and I again
connect the second set of coupling conductors and place a battery in the connection
between one couple and an induction coil in the connection between the other couple.
Mechanical connections are of course provided from the diaphragm of the transmitter
to the cells whereby the vibrations of the diaphragm simultaneously increases the
pressure on the material in one of each coupled pair of cells and relaxes the pressure
on the other cell, as a result of which action the battery current, following the line
of least resistance is, for the most part, switched in alternately opposite directions
through the induction coil connection.
In practice I have used two sets of electrode faces, four in each, and grouped to
form the walls of four resistance cells containing granular material, electrically
coupling the faces of one set in pairs and of the other set also in pairs, but in such
manner as not to couple the same cells coupled by the connections of the first set.
One set of electrode faces I secure in fixed position while the other set is movable
and mechanically connected to vibrate with the diaphragm, and my preferred
construction is that shown, having three electrode buttons arranged one behind the
other and the central button having two faces while the end buttons have each, one
inwardly turned face which faces are electrically coupled or connected together by a
wire, while the two faces of the central button are electrically coupled through its
central button, a wire serving to couple the central metallic button with the wire
connection between the two outer electrode faces. In connection with these fixed
electrode buttons I employ two movable buttons each having two faces coupled
through their metal backs and placed one on each side of the central stationary
button. The metal centres of these movable buttons of course serve to couple

page_text: alternate cells together and a wire connection between the two buttons makes up the
remaining coupling in the manner already described.
While, as I have stated, the construction embodying as above described the use of
four resistance cells, is my preferred construction for embodying the idea of imparting
to the transmitter a mode of action closely similar to a pole changing switch having
two movable portions, I have found that the features of my construction which
involve the rigid fastening of the stationary electrodes to the frame, a direct and
positive connection between the diaphragm and the movable electrode faces, and the
use of granular conducting material between such rigid and positively moving
electrode faces, can be advantageously applied in the construction of a telephone
receiver having two resistance cells coupled in such a way, hereafter to be described,
as to direct a portion of the battery current alternately in different directions through
a wire connection in which is situated the induction coil, and this is particularly the
case where the arrangement of the electrode buttons brings them all into line with
the diaphragm and where the connecting rod coupling the diaphragm with the
movable buttons passes through a stationary button.
Referring now to the drawings in which my invention is illustrated, and in
which
Figure 1 is a central longitudinal section through a transmitter embodying my
invention in its preferred and most satisfactory form.
Figure 2 is an enlarged sectional view of the electrode buttons and their connections
with the diaphragm.
Figure 3 is a transverse section on the line 1-1 of Fig. 1.
Figures 4 and 5 diagrammatic illustrations of the operation of my transmitter.
Figures 6 and 7 diagrammatic comparative illustrations of a pole changing switch
of analogous character, and
Figure 8 a central longitudinal section through a transmitter embodying some of
the features of my invention and adapted to attain some of the advantageous features
in operation.
A indicates the diaphragm of the transmitter in the centre of which a nut A¹ is
secured, B indicates the framing of the transmitter, C an extension of the frame
slotted, as indicated at C¹, and to which is secured the electrode box D) by means of
the binding screw E working in the slot C¹. The box D, as shown, has a cylindrical
internal conformation and is provided with heads F F by which this cylinder is closed.
G is the central stationary electrode, which I preferably contract of brass with
carbon faces as indicated at H H. The brass centre of this electrode button is
grooved, as shown at G' for the purpose of engaging with a binding screw I which
holds it in position in the box and by which it is electrically connected with other
parts of the apparatus.
The outer stationary electrodes are each formed with stems, as indicated at J
and K, these stems extending through the heads F F of the box to which they are
secured as shown, by the set screws ff. At the inner end of each rod is a brass
dise, indicated at J', and K', while J and K2 indicate brass discs screwing on the
stems J and K and acting to clamp a light felt washer L. between the discs Ja
and K2 and the discs J¹ and K. Carbon electrode faces are provided on each of the
discs J and K¹, as shown.
The movable electrode buttons, of which one is situated on each side of the
central stationary electrode are conveniently made up as shown of two brass discs,
such as are indicated at M M¹ and N N¹, a light felt washer L being clamped
between the discs in each case. The electrode N is secured to the diaphragm by a
light iron or steel rod 0, one end 0% of which is shown threaded and screwing into
the electrode button, while the other end 0' is threaded and screws into the nut A¹.
This rod is covered by a non-conducting jacket P which is partly enclosed by a
conducting tube Q which extends from a point on the rod lying outside of the hollow
stem K to the point where the movable electrode M is secured, said movable
electrode being attached directly to this conducting rod, which may conveniently be
of brass, and a convenient connection being, as shown, by means of a threaded

page_text: head Q on the brass tube. Outside of the brass tube Q there is another protecting
non-conducting jacket R. It will be noticed that the brass tubing does not pass
through the central stationary electrode and that I have indicated the non-conducting
jacket P of the central rod as enlarged between the two movable electrodes, such
enlarged portion being indicated at Pi
It will be understood of course that granular material, preferably carbon as
commonly used, is placed between each pair of electrode faces, there being thus
four separate bodies of granular carbon which are prevented from coming into
physical contact with each other or into electrical connection otherwise than
through the electrodes by the light felt washers L, the said washers also serving
to support and centre the electrodes.
It will also be noticed that the carbon facings of the central electrode and of
the stationary electrode K' through which faces the actuating rod for the movable
electrodes pass, have chamfered edges to their perforations making a nice fit with
the rod which passes through; the purpose of this construction being to prevent
the entrance of the granular carbon beyond the carbon facing of the electrodes,
and the niceness of the fit is to be determined by this purpose.
The two outer stationary electrodes are shown connected together by wires U
The connection of the outer electrodes
and U extending from their stems J and K.
with the central stationary electrode is shown as being made through a wire V
which extends from the connection U U¹ to the screw I and connects through said
screw with the central electrode. The connection between the movable electrodes
is conveniently made as indicated in Fig. 2 by wires T and T connecting with the
end Q2 of the brass rod Q and with the end O¹ of the central rod O.
I have indicated at W an induction coil in the wire V and at X the coacting coil in
It will be understood
the secondary line Y Y¹, and at S I have indicated a battery.
of course that the position of the battery and induction coil may be transposed, the
operation remaining practically the same.
The operation of my device can be readily followed from the diagrams, Figs. 4
and 5, in connection with the pole switch diagrams indicated in Figs. 6 and 7.
As the movable electrodes are, by the action of the diaphragm, impelled toward the
left the resistance to the passage of a current between the electrodes N and G and M
and K is diminished while it is increased as between the electrodes N and J and M
and G, consequently the greater part of the battery current will pass through the
wire T, the movable electrode N, the stationary electrode G upward through the
wire connection V, thence through the wire connection U to the stationary electrode K,
and thence through the movable electrode M and wire T to the battery. An impulse
to the right, as indicated in Fig. 5, reverses conditions producing, as there shown, a
downward current through the wire V; the changes from the one condition to the
other being of course gradual and without sensible interruption, and the result being
that practically the whole battery current is made to follow, with the utmost nicety,
vibrations of the diaphragmn of the transmitter.
The diagrams, Figs. 6 and 7, are simply supplied to show the familiar action of a
pole changing switch with two movable members, and it will be noticed by comparing
them with the diagrams, Figs. 4 and 5, that the action is almost exactly parallel, the
difference being simply that whereas the pole changing switch interrupts the current
abruptly the action of the transmitter switch, as I may call it, produces no abrupt
interruptions.
Referring to the modified construction shown in Fig. 8, it will be seen that the
construction of the box and of the two outer fixed electrodes are practically the same
as shown in Fig. 1, but that in place of a central fixed electrode and two movable
electrodes, the modification shows the use of a single central movable electrode con-
nected by the rod Owith the nut A' of the diaphragm A, said rod being suitably insulated
as by a non-conducting jacket P. In this transmitter there are but two bodies of
conducting granular material which however are alternately and synchronously
subjected to an increase and a relaxation of pressure as the movable electrode moves
backward and forward between the fixed electrodes, just as is the case with the two

page_text: masses of granular material on each side of each movable electrode shown in my
preferred construction shown in Fig. 1.
The two fixed electrodes in the construction shown in Fig. 8 are electrically
connected as by wires U U¹ a battery S being placed in this connection while a wire
connection V is led from the central movable electrode through the stem O to the
centre of the battery S, as indicated at V₁, an induction coil W being placed in this
connection and in proper relation to the induction windings X of the secondary
circuit Y Y¹.
It will be seen that in the construction shown, when the resistance developed by
both masses of granular material is equal the current of the battery S will pass
through the wire U' the stem J and electrode J' through the central electrode and
the electrode K¹, the stem K and the wire U back to the battery. When, however,
the movable electrode moves, for instance, to the right the conductivity of the right
hand resistance cell is increased and that of the left hand resistance cell 'diminished,
the current from the portion S¹ of the battery then tends to pass downward from the
central electrode through its connection V, while the current from the left hand
side S² of the battery attempts to pass upward through the connection V and thence
through the left hand resistance cell back to the battery, but the right hand circuit,
being that in which the least resistance is to be found, will dominate and the net
result will be a downward current through the wire V. When, however, the movable
electrode moves to the left the conditions are exactly reversed and an upward current
will pass through the connection V and through the compressed mass of carbon back
to the battery. In this way the movements of the electrode result, as in the first
case, in an alternation of the current in opposite directions through the connection
embodying the induction coil, but obviously this modified construction does not
enable me to utilize, as in the preferred form, substantially the whole force of the
battery, and I have described the modification of Fig. 8 chiefly to make clear how the
features of construction which I have above specifically noted are available in such a
construction as well as in that construction which forms the chief subject matter of
my invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a telephone transmitter, the combination of two relatively central and two
relatively lateral electrode faces, one pair being movable and one rigid in the sup-
porting frame, granular conducting material situated between the adjacent central
and lateral electrode faces, a diaphragm and a positive connection between it and the
two movable electrode faces whereby they are moved synchronously with the
diaphragm and so as to simultaneously relax the pressure on one mass of granular
material and proportionately increase it on the other mass.
2. In a telephone transmitter, the combination with the diaphragm of a perforated
electrode adjacent thereto and set at an angle to a horizontal plane, a rod extending
from the diaphragm through such perforated electrode, an electrode secured to the
said rod and granular conducting material situated between the electrodes.
3. In a telephone transmitter the combination of an electrode box as D with one
or more fixed electrodes situated therein, one or more movable electrodes also situated
in said box and attached to the diaphragm so as to move with it, and a light elastic
washer extending out from the periphery of the movable electrode or electrodes
serving at once to support said electrodes and to form partitions in the box.
4. In a telephone transmitter, a set of four resistance cells containing granular
conducting material, electrical connections coupling said cells in two pairs, an
electrical connection between said pair connections, other electrical connections
coupling said cells in two pairs the members of which are not connected by the first
pair connections, an electrical connection between the second pair connections, a
battery and an induction coil, one situated in the connection between the one set of
pairs and the other situated in the connection between the second set of pairs, and

page_text: mechanical connections from the transmitter diaphragm whereby the resistance of
the cells is varied as described and so as to cause the greater part of the battery
current to traverse the induction coil in alternately opposite directions.
5. In a telephone transmitter, a set of four fixed electrode faces in combination
with a set of four electrode faces attached to and movable with the diaphragm, said
faces of the two sets of electrodes being arranged opposite to each other in pairs and
so as to form walls of cells and the electrode faces being so arranged that with each
movement of the diaphragm two pairs will approach and two recede from each other,
granular conducting material placed between each pair of coacting faces in the cell
formed between them, electrical connections coupling one set of faces in pairs, an
electrical connection between said connections, electrical connections coupling the
other set of faces in pairs, said coupled faces being those belonging to cells not
coupled by the connections between the first set, an electrical connection between
the connections last mentioned, and a battery and induction coil one situated in the
connection between the coupled faces of one set and the other in the connection
between the coupled faces of the other set, all substantially as specified.
6. In a telephone transmitter the combination with a set of four fixed electrode
faces arranged parallel to and one behind the other, with a set of four synchronously
movable electrode faces arranged in line with the fixed faces and so as to form with
them the walls of four resistance cells, granular conducting material held in each cell,
electrical connections coupling the two outer and two inner electrode faces of one set
in pairs, and a connection between said pair connections, electrical connections
coupling the outer and adjacent faces of the other set in pairs and a connection
between said pair connections, a battery and an induction coil one situated in the one
and the other in the other connection between the coupled pairs of faces aforesaid and
mechanical means securing the movable electrodes with the transmitter diaphragm so
as to cause them to move therewith.
7. In a telephone transmitter the combination of one set of electrodes, the outer
ones having faces turned inward and the central one having two faces, and the two
outer ones electrically connected together and with the central electrode, with a
second set of electrodes, one situated on each side of the central electrode, an
electrical connection between said movable electrodes, means for securing one set of
electrodes with the diaphragm so as to move therewith, a battery and an induction
coil, one situated in the connection leading to the central electrode and one in the
connection between the set of two electrodes, all substantially as specified, and so as
to alternate the greater part of the battery current through the coil.
8. In a telephone transmitter the combination of three stationary electrodes, the
outer ones having faces turned inward and the central one having two faces, and the
two outer ones electrically connected together and with the central electrode, of two
movable electrodes actuated by the diaphragm and one situated on each side of the
stationary central electrode, an electrical connection between said movable electrodes,
a battery and an induction coil, one situated in the connection leading to the central
electrode and one in the connection between the movable electrodes, all substantially
as specified, and so as to alternate the greater part of the battery current through the
coil.
9. In a telephone transmitter the combination with the diaphragm of three
stationary electrode buttons arranged in line therewith and the two nearest to the
diaphragm being formed with perforations, two movable electrode buttons arranged
between the stationary buttons, one on each side of the central button, a rod attached
to the diaphragm and to the two movable buttons said rod passing through
the perforated stationary buttons, granular conducting material situated between the
adjacent faces of each electrode button and electrical connections as specified.
10. In a telephone transmitter, substantially as specified, the combination with the
electrode box of the two stationary end electrode buttons having electrical connections
extending through the ends of the box and the central stationary electrode button
having an electrical conductor extending through the side wall of the box.

page_text: 11. In a telephone transmitter, substantially as specified, the combination with the
electrode box of the two movable electrode buttons and an actuating rod embodying
two insulated conductors one connected with each button.
Dated this 22nd day of March 1898.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.