Year: 1886

page_text: шрготеше ш геторполе даного
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P.A. of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, in the County of Lancaster, and
323 High Holborn, in the County of Middlesex, Civil Engineer, do hereby
declare the nature of this invention (a communication from fabroad by Ezra'
Torrance Gilliland of Suffolk, County State of Massachusetts, in the United States
of America, Electrician) and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:―
This invention relates to that class of telephonic transmitters in which a variable
resistance medium such as granulated carbon or like imperfectly conducting material
is included in the circuit of a voltaic battery, which resistance is controlled by a
diaphragm or vibrating plate, and is adapted to be varied in exact correspondence
with the vibrations of said plate, when operated upon by sound waves produced
by the human voice, thus developing in the circuit, electrical variations corre
sponding in character to the said sound waves, which traverse the main line, and
which effect in turn, a fac-simile variation in the amount of attraction experienced
by a telephone receiving instrument included in the same circuit; the diaphragm
whereof in vibrating in response to the said varying attraction, reproduces the
original sounds.
The invention claimed in this application relates particularly to the form and
construction of the containing chamber for the said carbon granulations; to the
special form and relations of the electrodes; to the combination with the said
electrodes of the said granular mass of low conducting material; and to the
particular form of support or adjustable fixture which I have devised for the trans-
mitter proper; and finally to the form of air passage or speaking.tube by which
the sound waves are directed upon the diaphragm.
In the construction of transmitters based upon the above principles, it is
desirable that the chamber which encloses the varying medium be mounted hori-
zontally, and formed with walls of some suitable non-conductor; such as vulcanite,
or vulcanized fibre; the said chamber being closed at one end by the horizontal
D
077

page_text: vibrating diaphragm which constitutes or which supports one electrode of the
transmitter and at the other end by the opposite or complementary electrode
which preferably is supported by the upper edge of the wall of said chamber, and
which projects downwardly into the mass of finely divided conducting material,
so that its conducting surface is partially or wholly submerged thereby.
It is furthermore most desirable in order to obtain the clearest articulation, that
the conducting passage or speaking tube leading to the vibratory plate, or that wall
of the said passage upon which the said sound waves impinge, be constructed with
a plane surface between the diaphragm and the flaring external mouthpiece, as by
this means the sound waves experience a minimum amount of distortion, and those
which do not impinge directly upon the vibratory plate, are reflected immediately
thereupon from the said plane surface.
This passage accordingly projects downward from the diaphragm, and the
interior or rear wall thereof which is a plane surface, is mounted at an acute angle
with the said diaphragm. Heretofore, transmitting telephones of this character
have been constructed, comprising a fixed horizontal diaphragm, upon which the
carbon particles rested, but in which the air waves were directed upon the diaphragm
through a curved passage.
It has moreover been found most desirable in practice, to provide transmitters of
this class with an adjustable support, so that persons of tall or short stature may
without discomfort, employ them. In all cases where this has heretofore been
attempted, any change of adjustment with respect to height, has resulted in
interfering with the horizontality of the diaphragm and has thus proved pernicious;
since said horizontality has been demonstrated by experience to be an essential
element to the success of transmitters of this class.
This invention obviates this practical defect, and provides for the transmitter,
a support upon an adjustable hinged or jointed arm, having means whereby the
movement of the free end of said arm carrying the transmitter, will vary the
distance between the transmitter mouthpiece, and any external stationary object
without altering the relative position thereof; or in other words, the transmitter
may be adjusted to a higher or lower position, and to a position nearer or more
distant with respect to the person operating it, while the horizontality of the
diaphragm and containing chamber and the original position of the mouthpiece
remains unaltered. For example, the arm may be so arranged that the transmitter
can be raised or lowered to suit the varying heights of different speakers, while the
trumpet shaped mouthpiece is automatically adjusted to retain its initial relative
position, with the orifice directed towards the speaker, or what is the same thing
with the diaphragm maintained in a horizontal plane.
Further improvements consist: in employing means for making the electrical
connections, so as to secure facility in inter-changing parts; whereby a defective
element may be replaced without changing the entire instrument; in plating the
electrodes or conducting sides of the containing chamber with a substance which
will not oxidize or corrode by contact with the particles of the current varying
substance; and in certain details of construction and arrangement of parts which
are described with reference to the drawings.
In the accompanying drawings Figure 1 is a longitudinal cross section of the
transmitter, and its supporting arm. Figure 2 is a cross section on the line z z of
Figure 1.
Figure 3 is a cross section on line x x of Figure 1. Figure 4 is a cross section
at y y of Figure 1.
Figure 5 is a top plan view complete.
C is a metal casting, the upper section being cup shaped to receive the transmitter
electrodes and containing chamber T; the channel t constitutes a passage or tube
which in cross section resembles an ellipse (figure 2); this terminates in a mouth-
piece m; the wall of the channel t opposite to, or most remote from the speaker is
nearly flat; approximating to a plane surface; a lug or projecting piece j is integral
with the casting C, and is adapted to form a joint.

page_text: The transmitter proper, T, is composed of a ring b of insulating material threaded
upon the exterior; the upper edge is countersunk to receive the rim of the upper
electrode e which is immersed in a finely divided conducting substance, such as
carbon in granulations.
This electrode in external form resembles the pulley of a window shade roller
one of its flanges being wider than the other, and serving as the means whereby
the electrode may be hung on the upper edge of the chamber. The entire electrode
thus depends from the said upper edge and nearly fills the containing chamber,
its lower surface being thus brought very near to the inner surface of the
diaphragm.
Two reservoirs or depositaries open from above into the shallow space thus
formed between the diaphragm and the lower surface of the upper electrode; one
through the center, and the other at the circumferential edge of the inert electrode.
The central reservoir is in form like an inverted cone or funnel, and extends
vertically through the electrode. The upper orifice or base of the cone shaped
reservoir is flaring, but tapers downwardly finally terminating in a small hole or
opening by which carbon granules poured in the funnel find access to the diaphragm.
The outer reservoir extends entirely round the electrode and is formed by a groove
like that in the sheave of a pulley.
A number of channels are also provided, converging laterally from the circum-
ferential groove into the outer reservoir, through which the granulated material
may circulate.
.
The granulated resistance material may be poured into the funnel formed cavity
and passes partly, direct through to the diaphragm; and partly through the lateral
channels to the outer reservoir.
This is not however essential and it is sometimes found more convenient to set
the electrode in place in the containing chamber, and then to invert the same, fill
the reservoirs with the granulated carbon, and finally attach the diaphragm to the
lower side of the containing chamber.
This form however is not essential to the successful operation of the invention;
and any preferred form may be readily employed without detracting from its
excellence, provided only that it is insulated from the vibrating electrode, and
that its lower surface be wholly or partially buried in the granulated resistance
material.
The electrode e may be made of brass, and should be plated with gold, or coated
with platinum so that foreign matter in the carbon cannot corrode or oxidize it.
Or a carbon face may be given to it: The cap a has a rim, screw threaded on both
outsile and inside surfaces; this screws down upon ring b, and holds the electrode e
firmly in position. A centrally perforated ring c has a screw threaded rim, and
when the thin sheet of platinum forming the diaphragm d is in position, it is
screwed down upon the insulating ring b, and holds the diaphragm in position.
An air space or vocalizing chamber is provided by turning a shoulder upon the
interior of ring c as shown in the drawing.
The electrode e is connected with the battery through cap a, and the adjustable
arm A; the diaphragm constitutes preferably the vibratory electrode, although it
may if preferred, be constructed of non-conducting material and caused to support
a conducting electrode. For the purpose of connecting the diaphragm (or in the
latter case the electrode carried thereby) with the battery circuit and the primary
circuit of the induction coil and battery, a circular plate of brass o fitting the
cup C, is insulated upon its under side by an insulating bushing i and is placed in
the bottom of the cup C; the screw post q is electrically connected to plate o; the
diaphragm d when the transmitter is screwed into position in cup C, makes contact
with plate o; from post q an insulated conductor n is carried to a screw post, as 4,
with which the primary circuit of the induction coil I is connected.
The granulated or finely divided carbon is placed in the chamber formed by the
ring b, as herein before described; so as to rest upon the diaphragm, and to bury or
partially to bury the dependent electrode e.

page_text: D is a cast metal box which may be screwed to the wall. The requisite number
The inner
of insulated screw posts 3, 5, 7 and 9 are placed in the wall of box D.
ends of these screw posts, are headed, and the induction coil I fixed to the back-
board w, has the terminals of its two coils connected to springs or projections
as 1 and 2 which engage with, or make contact with the insulated screwposts; by
this arrangement of connections it becomes a very simple operation to change or
substitute one coil for another, and this improved feature that of the interchange-
ability of parts, is applied to the other elementary parts of this telephone.
The adjustable arm A is composed of two sections A and A¹, as shown in
Figures 1, 4 and 5.
'
These two sections embrace the projections S, and are pivoted thereto by pivot P ;
the two sections A and A¹ are also screwed together.
The free end of the arm, embraces projection j of the transmitter frame and a
pivot p retains the transmitter in a movable position. A metal bar B is pivoted
to the support S, at g, and to the frame of the transmitter T at f. Now as the
transmitter is raised or lowered to vary its distance from any stationary object, or
to place it at a more convenient height for the user, the bar B holds the trans-
mitter T in its initial position with its diaphragm in an horizontal plane; this
automatic adjustment of the relative position of the transmitter prevents the
displacement and disarrangement of the mass of finely divided conducting material
forming the contact varying medium, and prevents any disturbance of the initial
adjustment. The same arrangement would be applicable to retain any other
relative position in which it might be found desirable to set the instrument.
The spring 8 and link act as a counterweight, and counteract the tendency of
the arm to drop. The operation of the transmitter is similar to that of other
telephonic transmitters.
For very short distances the use of an induction coil is not absolutely essential,
as the transmitter may be placed in direct circuit with the battery and receiver;
but an induction coil enables the same instrument to be employed on long or short
circuits with equal facility, and its employment is therefore preferred. The
secondary coil may by means of the two screw terminals 3 and 5 be connected
with the line; while the remaining terminals 7 and 9 may be connected with the
two wires of a battery.
Having thus described the nature of this invention, and the manner in which
instruments based thereon, are to be made, as communicated to me by my foreign
correspondent, I would have it understood that I claim
1. The combination in a telephone transmitter of a horizontal diaphragm
controlling the current varying medium which is located or resting thereon with a
downwardly projecting speaking tube or passage for directing the air waves
thereon, having a plane side or wall upon which the air waves impinge, and are
directly reflected to the diaphragm.
2. The combination in a telephone transmitter of a fixed horizontal diaphragm
upon which the current varying medium rests; and a downwardly projecting tube
or passage, the interior wall of which remote from the operator, is substantially a
plane surface, and is fixed at an angle with the diaphragm, whereby sound waves
may be reflected therefrom directly upon the said diaphragm.
3. A telephone transmitter comprising in combination, a fixed horizontal vibratory
plate; a containing chamber of which the said plate is one side, and which has
walls of non conducting material; a complementary electrode supported by the
upper edge of the said chamber, and projecting downward therefrom, into the said
chamber; and a mass of finely divided conducting material resting on the said
vibratory plate, and partially burying the said complementary electrode substan-
tially as described.
5. A telephone transmitter supported by a hinged or jointed arm adjustably with
respect to its distance from a given point or object; combined with means adapted
to automatically preserve the relative position of the transmitter with respect to

page_text: the said fixed point unchanged, when the arm is moved to vary the distance
therefrom,
6. The combination of a telephone transmitter pivoted upon the free end of a'
hinged or jointed arm; and a mechanical connection of the character described,
between the said transmitter, and a fixed support, whereby the transmitter is
enabled to be moved for the purpose of altering its beight without interfering with
the horizontality of the diaphragm.
7. A telephone transmitter having a fixed horizontal vibratory plate upon which
the current varying medium rests; and a downwardly projecting tube or passage,
through which the sound waves are directed upon the said vibratory plate; com-
bined with a jointed arm supporting the transmitter; and a mechanical connection
between the transmitter, and a fixed support, whereby the movement of the trans-.
mitter to vary its height is automatically caused to maintain the mouthpiece of the
said tube in its normal plane, and to maintain likewise the diaphragm in its normal
horizontal plane.
8. In a telephone transmitter of the herein described class, an electrode coated,
plated or covered with a non corrosive substance.
9. A telephone transmitter comprising in combination, a fixed horizontal vibratory
plate constituting or supporting one electrode of a battery circuit; a containing
chamber having walls of non conducting material, and closed on one side by the
said vibratory plate; an opposite electrode plated with a non-corrosive metal
supported upon the upper edge of the said chamber and projecting therein; and a
mass of granulated carbon partially filling the said chamber supported by the
vibratory plate and surrounding the projecting part of the complementary electrode,
substantially as described.
10. The combination in a telephone of two or more parts or elements, each
element having one or more electrical contact points, springs or projections,
registering with, and adapted to form contact with an equal number of electrical
contact points, springs, or projections upon the other; for the purpose of facilitating
interchangeability of parts.
11. The combination in a telephone transmitter of an enclosing ring of insulating
material, a perforated screw threaded ring for clamping the diaphragm thereto;
a mass of finely divided conducting material confined within the enclosing rim; an
insulated screwpost in electrical contact with the diaphragın and connected to one
pole of the battery by a flexible insulated conductor; and a cap or cover for the
said enclosing ring electrically connected through a metallic supporting arm with
the other pole of the battery.