IMPROVEMENTS IN TELEPHONIC RECEIVERS
Year: 1884

page_text: I WILLIAM PHILLIPS THOMPSON, Fel. Inst. P.A., of the Liverpool and London
Agency for Foreign Patent Solicitors, 6 Lord Street, Liverpool, in the County of
Lancaster, Civil Engineer do hereby declare the nature of the said Invention for
IMPROVEMENTS IN TELEPHONIC RECEIVERS" and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
The Invention relates to the class of instruments employed for translating into
corresponding air vibrations or sound waves, the variations in the strength of an
electric current which have been established through the agency of vocal or other
sounds.
The object of the Invention is to provide means for producing from the
variations of the character mentioned, better and more effective results than it has
usually been possible to obtain from the diaphragms of the telephones now in
common use.
It is a well-known fact that electric currents when they are caused to traverse
neighboring parallel. conductors in the same direction, exert upon each other an
attractive force, and when in opposite directions a repulsive force; and the degree
of force with which they so attract or repel, is dependent upon the proximity
of the conductors and the strengths of the currents. When therefore the
positions of the conductors are approximately constant, the variations in force
may be considered as depending upon the variations in strength. Parallel
results are obtained when an electric current is caused to pass through a single
electric conductor in proximity to a continuation of itself. Upon this principle
the Invention is essentially based, and it consists generally in so disposing one or
more electric conductors that different portions of the lengths of the same are
brought into proximity to each other, and currents of electricity caused to
traverse the same will pass and repass in approximately parallel directions or in
opposite directions through such different portions. Suitable means are provided
for supporting such a conductor and for receiving electric connections therewith
so that it may be conveniently included in a telephonic circuit. To this end the

page_text: conductor or conductors may be arranged in the form of one or more flat spiral
coils, and this is usually the preferable organization. The electric current is then
caused to traverse the convolutions of each coil in succession and thus to exert
upon itself an attractive or repulsive force. This force will vary with the
variations in the strength of the current. The flat spiral coils, when more than
one is employed are preferably placed in planes, parallel with each other and they
are preferably so connected with each other that a current of electricity traversing
the same will pass in parallel or approximately parallel directions through the
convolutions of the two or more spiral coils. The parts may however be organized
to cause the currents to pass in opposite directions through the different coils and
it is not always necessary that the spiral coils be flat, for they may be made convex
or otherwise modified in form.
The spiral coils or other arrangement of conductors are mounted upon any
suitable supporting material which may or may not serve to assist in establishing
the acoustic vibrations, thus they may be secured upon the flat surfaces of resonant
plates such as are now commonly employed in telephonic receivers, or they may
be wound upon cylindrical supports or upon cones, or they may be embedded in
some glutinous material such as varnish or shellac, or mounted upon non-magnetic
plates.
Such an instrument will be found to respond readily and very effectively to the
variations in an electric current which are produced by means of any convenient
form of telephonic transmitter; it will be found also that a simple spiral coil of
wire constructed upon this principle will produce a similar result though of a less
pronounced character. In either case acoustic vibrations will be established by
the receiver which correspond to the vibrations whereby the changes in strength
of current were primarily occasioned.
The volume of the intensity of the sound which is obtained from the action of
the convolutions of the conductor may be considerably intensified by placing a
plate or other body of iron in proximity to the supporting plates of the coils. For
this purpose it is desirable either to place a thin flat plate of iron between the
confronting coils when two or more flat coils are employed, and to support the
same in such a position in any convenient manner, or a plate of iron, which may
be quite thick, may be placed against the surface of one of the supporting plates
opposite the coil of wire which is secured to the same plate, and in general it will
be found advantageous to place a greater or less body of soft-iron in proximity to
the conductor however arranged.
For the purpose of still further aiding or adding to the acoustic effects which
may be derived from the instrument, it is desirable to perforate one of the
supporting plates, when flat plates are employed, at or near its centre, thereby
permitting any motion occurring within or between the plates to more readily
impart itself to the surrounding air.
The. Invention is not however confined to the organization of an electric
conductor in the precise manner described in the foregoing, for it is evident that
there are numerous other ways in which the conductor may be disposed for securing
the same or similar results upon the same principle. Typical organizations will be
described in connection with the Drawings.
In the accompanying Drawings, Figures 1 and 2 are theoretical diagrams
illustrating different methods of disposing and connecting the conductors;
Figure 3 is a plan view of an instrument based upon the principle of the Invention,
and Figure 4 is a vertical transverse section of the same. Figures 5, 6, 7 and 8
respectively illustrate modifications.
In Figures 1 and 2 two different methods of, connecting the conductor, when
arranged in spiral coils, are illustrated. According to the plan illustrated in
Figure 1, the current is caused to enter at the terminal d 1 and to pass in .the
direction indicated by the arrow from the exterior to the interior convolutions of
the spiral coil c 1, the direction in each convolution being parallel to the direction
in the neighboring convolutions. From the interior convolution. the current.passes

page_text: through the connecting portion d 3 to the inner convolution of the spiral coil o 2
and in the direction indicated by the arrows through its several convolutions to
the terminal d 2. It will be seen thus that the current is caused to traverse both
conductors in parallel directions and the two spiral coils will be attracted toward
each other by means of the attractive force exerted by the current upon itself in
the several portions of the conductor. This attractive force is variable by reason
of the variations in the strength of the current which are caused by the action of
the transmitter. The variations in attractive force thus caused, cause a vibration
on the part of the receiving instrument capable of producing sound waves or
sonorous vibrations corresponding to those by means of which the current variations
were originally occasioned..
In Figure 2 an organization is illustrated in which the connections of the two
spiral coils are so changed that the current is caused to traverse the same in
opposite directions; thus the current from the interior convolution of the spiral
coil c 1 passes directly to the interior convolution of the spiral coil c 2 and thence
to its outer convolution, in the direction indicated by the arrows. The relative
directions are thus reversed. The operation of such an instrument is precisely
similar to that described in connection with, Figure 1, with the exception that the
variations in the repulsive force of the two currents is here availed of, in so far
as the two spirals may act upon each other, instead of the like variations in the
attractive force. The results obtained are .however essentially the same in
either case.
Referring now to Figures 3 and 4, A represents a suitable case of hard rubber or
other suitable material for supporting the several parts of the instrument. This
case may be constructed in the form of a wide ring in,two sections a 1 and a 2
adapted to be screwed together as shown, or they may be constructed in any other
convenient form. A suitable ear-piece is preferably applied to the instrument.
Within the case A are supported two plates C1 and C2 which may be of metal
similar to the diaphragms usually employed in the well-known forms of telephones;
or they may be constructed of paper, vulcanized fibre, glass, wood, porcelain or
other suitable material. One of the plates C 1 is preferably perforated at its
centre, as shown at f1, for the purpose of more readily permitting the sound
waves to escape from the interior of the instrument. The plates are separated a
slight distance from each other by means of an intervening ring a 3 or by any
other suitable means. Upon the confronting surfaces of the two diaphragms are
placed two flat spiral coils of wire, of the general character represented in Figure 1
or in Figure 2, as shown at c1 and c2 respectively. Thèse coils are preferably
secured to the plates by means of a thick varnish or other similar material and
they are connected with each other in such a manner that a current of electricity
entering one terminal d 1 will pass through the coils in succession, and through
the convolutions of the same in parallel directions.
The two terminals d 1 and d2 are secured to suitable binding posts el and e 2
by means of which electrical connections may be conveniently established with the
same when the instrument is put in use.
The current employed for operating the instrument may be obtained in any of
the usual manners. In practice it will be found convenient to employ a Reis
transmitter or other similar instrument adapted to vary the strength of an electric
current correlatively with the sound waves embodying the words which it is
desired to transmit.
Between the two plates C1 and C2 there may be supported in any convenient
manner a soft-iron plate C3. Such a plate it is found will serve to considerably
intensify the effects of the instrument. This plate may or may not be perforated
at its center, as shown at ƒ 2, in the manner of the plate C 1.
Whatever effects are produced upon the air by the action of the spiral coil c I
and 2 and the plates C3 are more readily communicated to the outer air and
thus to the sense of the operator by the presence of the perforation f 1.
•

page_text: In Figure 5 a different method of applying the reinforcing plate is shown.
According to the plan illustrated in this Figure the plate C 3 shown in Figures 3
and 4 is replaced by a thick body of iron C4 which is placed against the side of
the supporting plate C2 opposite the coil c 2. The plate C4 is preferably in
contact with the surface of the plate C 2 and it is supported, in its proper position
in any suitable manner. The reinforcing plate C3 or C 4 is especially designed to
be employed in connection with non-magnetic supporting plates for the conductors,
though it is evident that it may also be applied to supporting plates of magnetic
material.
In some instances it may be found desirable to support the coils or other
arrangement of conductor or conductors directly upon the surfaces of soft iron
disks or plates. To this end the conductor may be secured directly to the inner
surfaces of a flat or a concave soft iron box as shown in Figure 6.
Referring to this Figure, A represents a suitable case of soft iron constituting at
the same time a support for the several parts of the instrument, and a resonant
body for intensifying the sound vibrations produced thereby. This case may be
constructed in the form of a flat circular box consisting of a cover a³ and a main
portion as which are adapted to be fitted together as shown; or they may be
constructed in any other convenient form. The flat portion C³ of the top a³ of the
box or case is preferably perforated at its centre, as shown at f³, for the purpose
of more readily permitting the sound waves to escape from the interior of the
instrument. Upon the inner surface of the flat portion C of the top of the box is
placed a flat spiral coil of wire and likewise upon the flat portion c of the
bottom a is placed a similar coil of wire, as shown at cs. The coils are preferably
secured to the surfaces of the iron plates by means of a thick varnish or other
similar material, and they may be coupled in either of the manners described in
connection with Figures 1 and 2. The conductor c³, ce is preferably, for use under
certain conditions, itself of soft iron for the purpose of rendering the operation of
the instrument still more effective, Such a conductor will be found effective in
connection with currents of considerable electro-motive force. Conductors formed
from other metals may however be employed in this form of instrument.
The two terminals d³ and d are secured to suitable binding posts e³ and e¹ by
means of which electrical connections may be conveniently established with the
same when the instrument is put in use.
It is not always necessary that the coils c and c be employed, for either might
be made use of without the other. Still another modification is to combine with
an instrument of the character shown in Figure 6, an intervening soft iron disk
similar to the disk C shown in Figure 5, and both surfaces of this disk may be
covered with coils or other arrangement of the conductor in a manner similar to
the plates or disks C and C. The portions of conductor upon the several plates
may be connected in series or in multiple arc, as desired in any instance.
In Figure 7 another modification is illustrated. The organization shown in this
Figure consists of two plates C and C which are preferably of soft iron, but
which may be of other material, supported upon a spool or core g¹ of wood or other
suitable material. The plates are separated from each other a slight distance, say
one-sixth or one-eighth of an inch, though the distance may be varied considerably;
and between the plates is wound a thin insulated conductor c'. The two terminals
of this conductor may be provided with any suitable means for establishing electrical
connections. Instead of a single electrical conductor c two or more conductors
may be wound upon the spool g¹, and the terminals of the same may be so
connected that the electric currents will traverse the conductors in the same or in
opposite directions.
Still another modification is illustrated in Figure 8, in which A¹ represents a
frame of rectangular or other suitable shape.
The two ends aª and a7 are
preferably of soft iron or copper or other suitable conducting material; and they
are insulated from the sides a which are preferably of soft iron by sections alo
of non-conducting material. The entire frame may however be of 'wood,

page_text: hard rubber or other suitable non-conducting material, and the ends provided
with thick conductors. From one to the other of these conductors extend
any suitable number of parallel insulated conductors c, the respective ends. of
which are in electrical connection with the conductors as and a7. When
the instrument is placed in use the incoming main line is connected with
one of the end conductors a and the outgoing main line with the corresponding
conductor a. The conductors c form thus a large number of paths for the passage
of the current between the conductor a® and the conductor a. It is not however
always necessary that the conductors c be connected thus in the main line in
multiple arc, for a single electric conductor may be wound continuously upon the
frame and the currents from the main line caused to traverse the entire length of
the same; or the two or more conductors may be so wound. In this construction
it is evident that it is not necessary that the end pieces of the frame be of
conducting material. Still another modification of the Invention consists in
weaving the conductor or conductors together.
Two or more of the organizations described in connection with Figure 8 may be
combined by placing them parallel with each other, or by locking them together
at angles with each other, or by causing them to radiate from a common centre.
There are various other methods of disposing the conductors, such as winding
them upon a cylinder or upon a hollow cone, and placing two or more such
cylinders or hollow cones, the one within the other, arranging the conductors in a
spherical form, et cetera, but a sufficient number of these forms have been set forth
to illustrate the Invention.
The theory of the operation of the instruments of the character described, which
was set forth in the early part of this Specification is that upon which it is thought
that they principally depend, but at the same time it is considered that there may
be more or less molecular action upon the part of the conductors themselves and
such action may and probably does in some instances lend assistance to the
acoustic effects of the instruments.
Having thus described the nature of this Invention and the manner in which
it is to be performed as communicated to me by my foreign correspondent, I would
have it understood that I claim ; —
-
1. A telephone receiver which is thrown into vibration by the varying force or
attraction or repulsion mutually exerted between different portions of the same
electrical conductor, when said conductor is traversed by an electrical current of
varying strength.
2. The combination, substantially as hereinbefore set forth, of an electrical
conductor formed into two confronting flat spirals situated in parallel planes, and
means substantially such as described for supporting the same in position.
3. A telephonic receiving instrument consisting of an electrical conductor formed
into one or more spiral coils, and means serving to support the spirals in their
relative positions.
4. A telephonic receiving instrument consisting of an electrical conductor so
disposed that the different portions of its length extend in directions parallel to
each other.
5. A telephonic receiving instrument, consisting of an electric conductor so
disposed that an electric current traversing the same will cause a variable attractive
or repulsive force to be exerted between different portions of the conductor.
'
6. In a telephone receiver which is thrown into vibration by the varying force
of attraction or repulsion mutually exerted between different portions of the same
electrical conductor, when said conductor is traversed by an electrical current of
varying strength, a plate or mass of soft iron serving to reinforce the vibrations of
the same.
7. The combination, substantially as herein before set forth, of an electrical
conductor formed into two confronting flat spirals situated in parallel planes, and a
plate of soft iron intervening between the same.
8. A telephonic receiving instrument consisting of an electrical conductor formed

page_text: into one or more spiral coils, means serving to support the spirals in their relative
position, and a soft iron plate intervening between the same.
9. A telephonic receiving instrument consisting of an electrical conductor so
disposed that the different portions of its length extend in directions parallel to
each other, and two non-magnetic plates upon which said coils are respectively
supported.
10. A telephonic receiving instrument consisting of an electrical conductor so
disposed that the different portions of its length extend in directions parallel to
each other, two non-magnetic plates upon which said coils are respectively supported,
and a soft iron plate serving to reinforce the vibrations imparted to said
non-magnetic plates.
11. A telephonic receiving instrument, consisting of an electric conductor so
disposed that an electric current traversing the same will cause a variable attractive
or repulsive force to be exerted between different portions of the conductor, a
non-magnetic support for said conductor and a plate of soft iron placed in proximity
to said conductor.
12. In a telephone receiver the combination substantially as herein before set
forth, of a vibrating medium, two enclosing plates for the same one of which
plates is perforated, substantially as described.
13. In a telephone receiver which is thrown into vibration by the varying force
of attraction or repulsion exerted between different portions of the same electrical
conductor, when said conductor is traversed by an electrical current of varying
strength, the use of soft iron for reinforcing the action of the instrument.
14. A telephonic receiving instrument consisting of an electrical conductor so
disposed that the different portions of its length extend in directions parallel to
each other, and an iron case upon or within which said conductor is supported.
15. A telephonic receiving instrument, consisting of an electric conductor so`
disposed that an electric current traversing the same will cause a variable attractive
or repulsive force to be exerted between portions of the conductor, and an iron
case in which said conductor is supported.
16. The combination, substantially as hereinbefore set forth, of an electrical
conductor formed into two or more flat spirals situated in parallel planes, and soft
iron plates for supporting the same.
17. A telephone receiver consisting of the combination, substantially as herein-
before set forth, of two soft iron plates, a non-magnetic supporting spool or core
for the same, a coil of insulated wire surrounding said spool or core, and means for
attaching conductors to the terminals of said coil.
18. A telephonic receiving instrument consisting of a series of parallel insulated
electric conductors included in the circuit of a main line in multiple arc, substantially
as described.
19. A telephonic receiver consisting of one or more insulated electric conductors
wound upon a flat supporting frame and provided with means for securing electrical
connections therewith, substantially as set forth.