IMPROVEMENTS IN TELEPHONES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Webster Gillett at the Office
of the Commissioners of Patents on the 30th October 1883.
:
WEBSTER GILLETT, of the Town of Flushing, in the County of Queens, and
State of New York, one of the United States of America. " IMPROVEMENTS IN
TELEPHONES"
This invention relates to telephones or apparatus for reproducing articulate
sounds at distant points by the aid of electricity.
I employ a series of independent telephonic transmitting devices operated by one
and the same action of the voice, and all contrib¨ting to the effect produced at the
other end of the line.
I prefer four sets of these parts, but it must be understood that I am not confined
to four; I can use a larger number. A less number as three, may serve with some
success.
I mount a series of pairs of electrodes near each other, and in contact with a
rigid piece recieving motion from a diaphragm. The rigid piece may be a concave
disc, firmly fixed by its centre to the centre of the ordinary vibrating diaphragm.
It communicates the motion of that point to a serios of pins, which, delicately
mounted and adjusted, each serves as one of the electrodes. I insulate the arms on
which these are mounted, and make independent connections from each arm to its
proper induction coil.
I control the series of local batteries, each operating its proper induction coil, by
a single switch operating a single wire properly connected to the whole. I make
one ground wire, with suitable conuections, serve for the whole series of induction
wires, each receiving its proper action from an independent induction coil. In the
receiving instrument, I provide effecient means of adjustment by making the case in
two parts joined by a screw thread.
I provide a pinching-scrow and jam-nut to ensure the maintenance of the
adjustment when obtained. The receiving instrument contains a hollow magnet

page_text: inclosing an inner magnet, each permanent, but subject to the influence of the
undulatory induction current transmitted over the line, which is applied by being
led around these magnets, the outer end of a coil which surrounds the inner
magnet being connected to the inner end of a coil which surrounds the outer
magnet, and both being wound in the same direction.
I provide by an annular bead on the face-piece of the receiving instrument
acting against a proper surface on the adjacent portion of the case, for holding
the diaphragm of the receiving instrument with sharply defined edges, thereby
contributing to the clearness of the sound.
In the transmitter, to the middle of the diaphragm is connected a concave disc,
firmly secured to the diaphragm by a screw. The disc partakes of all the
movements of the centre of the diaphragm. -
To a ring are rigidly secured by screws four arms, each separated from the ring
by insulators, of hard rubber, or other non-conducting substance. A wire, makes
an electrical connection between each arm, and the negative pole of a battery.
The arms extend inward until they nearly. touch each other. The inner end of
each is screw-threaded to match the screw-threaded interior of a cylinder inserted
therein, which is provided with an enlarged head or wheel, in which are bored holes
adapted to receive a lever not represented, by which it can be turned to adjust it
with any degree of nicety in its bearings in the arm.
The interior of each cylinder is equipped with two discs of soft vulcanized rubber
or analogous material between which is imprisoned a quantity of granulated gas,
carbon, or other substance of high resistance, having preferably a fineness about
equal to ordinary rifle powder. One of these discs is perforated in the line of its
axis, and receives a pin having an enlargement or head which, when the pin is
pressed home, bears firmly against the outer face of the disc, with the other end of
the pin extending a little distance into the powder.
A conducting wire connects the head of each pin with the positive pole of the
sane battery, which connects by the wire to the arm.
It follows that there is a circuit from the battery through the wires which is
obstructed by its difficult passage from the pin, through the granulated carbon to
the interior of the cylinder. The force of this current will vary with every;
fluctuation in the conductivity.
When a word is spoken into the mouth-piece and vibrates the diaphragm the
vibrations of the centre of the diaphragm, are communicated through the concave
disc equally to all the pins and induces fluctuations in the force of the current
through each of the four sets of wires.
To the two ends of the induction coil, which is wound in the usual way on the
induction spool, are connected two conducting wires. Either of these wires may,
by connecting one with the earth and the other with the line serve to transmit its
current over the line and induce vibrations at the other end..
All four sets communicate simultaneously the same signals. I arrange-for
combining them and sending the united effect of the four over the same line wire.
The primary currents through the batteries and their respective wires pass at
one point through a single wire, so that a single switch plug may connect and
disconnect the whole at once.
The batteries are all connected to the induction coils in the same manner and
direction, and the induction coils are all wound in the same direction relatively to
each other.
'
Two parts screwed together constitute the main body of the case of the receiving
instrument. I employ a check-nut or a threaded ring adapted to be screwed down
tightly against the edge of one part when rightly adjusted and to hold them firmly
in that adjustinent.
A pinching screw tapped through a boss formed on one part and engaging gently
on the screw-threads of the other part induces sufficient friction to hold the
adjustment firmly. A smooth or threadless place may be produced to receive the
point of this screw if preferred.
'

page_text: An annular bead is arranged to grip the diaphragm along a narrow line. This
gives the diaphragm unusually clear action. It sharply defines the portion which
is left free to vibrate, analogous to the frets on a guitar to receive the strings as
they are pressed down at the different points by the fingers.
I employ a permanent magnet straight and cylindrical. There are collars thereon
near the front end. The space between serves as a spool on which is wound a mass
of covered wire.
This magnet is enclosed in another permanent magnet in the form of a hollow
cylinder, on the exterior of which are two collars between which are wound a
number of convolutions of covered wire, which is electrically connected by soldering
or otherwise to the wire which, is wound the same way, on the inner magnet, the
outer end of the inner coil, being united to the inner end of the outer coil.
'
There is a cross-bar fitting tightly in holes bored or otherwise produced both in
the exterior hollow magnet and the inner.magnet. It holds the two magnets in
their exactly correct positions axially, relatively to each other.
A screw inserted through the centre of the end of the back piece, is tapped into
the inner magnet and on being set up tightly draws the centre magnet forcibly,
back, producing a strain on the cross bar. This construction holds both magnets
very rigidly to each other and to the back piece, and allows both magnets to be
reliably adjusted by a single movement, turning the back piece within the front
piece, with their screw-threads engaged as shown,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Webster Gillett in the Patent Office on the 29th April 1884.
WEBSTER GILLETT, of Flushing in the County of Queens and State of New
York, one of the United States of America, Electrician IMPROVEMENTS IN
TELEPHONES
This invention relates to telephones or apparatus for reproducing articulate sounds
at distant points by the aid of Electricity.
I employ a series of independent telephonic transmitting devices operated by one
and the same action of the voice, and all contributing to the effect produced at the
other end of the line.
I will show four sets of theso parts, but it must be understood that I am not
confined to four; I can use a larger number. A less number, as three, may sorve
with some success.
I mount a series of electrodes near each other, and in contact with a rigid piece
receiving motion from a diaphragm. The rigid piece is a concave disc, firmly fixed
by its centre to the ordinary vibrating diaphragm. It communicates tho motion of
that point to a series of pins, which, delicately mounted and adjusted, each serve
as one of the electrodes. I insulate the arms on which these are mounted, and
make independent connections from each arm to its proper induction coil.
I control the series of local batteries, each operating its proper induction coil, by
a single switch operating a single wire properly connected to the whole. I make
one ground wire, with suitable connections, serve for the whole series of induction
wires, each receiving its proper action from an independent induction coil. In the
receiving instrument, I provide efficient means of adjustment by making the case
in two parts joined by a screw-thread. I provide a pinching-scrow and jam-nut
to insure the maintenance of the adjustments when obtained.
The receiving
instrument contains a hollow magnet enclosing an inner magnet, each permanent,
but subject to the influence of the undulatory induction current transmitted over
the line, which is applied by being wound around these magnets, the outer end
of the coil which surrounds the inner magnet being connected to the inner end of
the coil which surrounds the outer magnet, and both being wound in the same
direction.
I. provide by an annular bead on the face-piece of the receiving instrument
acting against a proper surface on the adjacent portion of the case, for holding
the diaphragm of the receiving instrument with sharply defined edges, thereby
contributing to the clearness of the sound.
The following is a description of what I consider the best means of carrying
out the invention. The accompanying drawings form a part of this specification.
Figure 1. is an elevation of the transmitter, showing the interior or back faco.
Fig. 2 is a section on the line in Fig 1. This shows one of the adjustable
cylinders and adjacent parts in elevation.
Fig. 3, is a section through the cylinder and immediately adjacent parts on a
larger scale.
Fig 4, is a section on the line y y in fig. 1, on the same scalo as Fig. 3.
Fig 5 is a longitudinal section through the receiver.
Fig 5 is a section of a portion on a larger scale.
Fig 6. is a diagram of the instruments with their connecting wires, batteries and
ground connections.
Similar letters of reference indicate corresponding parts in all the figures whero
they occur.

page_text: In the transmitter, figures 1 to 4, A' is a mouth-piece fitted in a board A, in
rear of which is mounted a diaphragm B, firmly clamped by a ring D³. To the
middle of the diaphragm B is connected a concave disc B', firmly secured to
the diaphragm by a screw B³. The disc B¹ partakes of all the movements of the
center of the diaphragm.
To the ring D³ are rigidly secured by screws D' four arms D, each separated
from the ring Ds by insulators D', of hard rubber, or other non-conducting.
substance. A wire d makes an electrical connection between each arm D and
the negative pole of the battery L.
.
The arms D extend inward until they nearly touch each other. The inner ond
of each is screw-threaded to match the screw-threaded exterior of a cylinder G,
inserted therein, which is provided with a large head or wheel G', in which are
bored holes adapted to receive a lever, (not represented), by which it can be turned
to adjust it with any degree of nicety in its bearing in the arm D.
The interior of each cylinder G is equipped with two discs of soft vulcanized
rubber or analogous material, I I¹, between which is imprisoned a quantity of
granulated gas carbon J or other substance of high resistance, having preferably
a fineness about equal to ordinary rifle powder. The disc I' is tight; the disc I
is perforated in the line of its axis, and receives a pin E, having an enlargement or
head, which, when the pin is pressed home, bears firmly against the outer face of
the disc I, with the other end of the pin extending a little distance into the
powder J. The disc I is firmly pressed home in the cylinder by means of an
internally flanged and threaded thimble G³.
: A conducting wire c connects the head of each pin E with the positive pole of the
same battery which connects by the wire d to the arm D. It follows that there is
a circuit from the battery through the wires d e, which is obstructed by its difficult
passage from the pin E-through the granulated carbon J to the interior of the
cylinder G. The force of this current will vary with every fluctuation in the
conductivity.
A variable pressure exerted on the head of the pin E will induce a fluctuation in
the force of the current for two reasons: the pin E will be thrust further in and
withdrawn, thus increasing and diminishing the amount of surfaces in contact
between the pin E and the powder J. This is one means by which the conductivity
is varied. Furthermore the shoulder formed by the head of the pin E rests fairly
against the outer face of the soft rubber disc I, and every variation in the pressure
on the pin will be transmitted through the disc and felt by the powder J. Each.
variation in the pressure on the powder J changes its conductivity. This is the
second means by which the conductivity is varied. These two fluctuations operate
always in the same direction to re-enforce each other; an increased pressure on the
head of the pin E results in both an increased pressure on the powder J and also a
thrusting of the pin E deeper into the powder; and a diminution of pressure on
the head of the pin E results in a diminution of pressure on the powder J and
the partial withdrawal of the pin E from the powder so as to diminish the surfaces.
in contact. The parts are so proportioned that the heads of the pins are presented
near the periphery of the concave disc B¹. In adjusting the apparatus the
cylinders G are turned around so that by the engagement of their screw-threaded
surfaces in the arms D they are set so that the head of each pin makes the delicate.
contact with the disc B' sometimes known as telephonic contact.
When a word is spoken into the mouth-piece A', and vibrates the diaphragm B,
the vibrations of the center of the diaphragm are communicated through the
concave disc B¹ equally to all the pins E, and, by the two means described, induces
fluctuations in the force of the current through each of the four sets of wires de.
An induction spool F is included in each circuit. The induction coils may be of
the ordinary construction, a coarse insulated wire being wound around a core of
soft iron wires carrying the primary current from the connected battery I, while a.
fine insulated wire, wound exterior thereto, is ready to transmit through suitable
connections the secondary current which is produced in this closely associated fine

page_text: J
:
wire, by what is known as-induction, at each fluctuation in the force of the primary
current.
To the two onds of the induction coil, which is wound in the usual way on the
induction spool F, are connected two conducting. wires fh. Either of these
wires fh may, by connecting one with the earth and the other with the line M,
serve to transmit its current over the line and induce vibrations at the other end.
All four sets communicato simultaneously the same signals. I arrange for
combining. them and sending the united effect of the four over the same:
line wire.
F is the ground plato at the transmitting end of the line; f' is a single wire
leading therefrom to the vicinity of the instrument, where it is connected by
switch-plugs C with the several wires fleading to the four induction spools F.
K. is the ground plate at the opposite end of the line; is a single wire
connecting from K through tho receiving instrument and through the lino M to
the vicinity of the transmitting instrument, where it is connected to each of the
four wiros h leading back to the induction coils in the respective induction.
spools F.
A connection very similar to this is made with the primary currents.
The primary currents through the batteries L and their respective wires de
pass at one point through a single wire e³, so that a singlo switch plug C¹ may
connect and disconnect the whole at once. The arrangement to effect this is
indicated in fig. 6, where the four wires e, leading from the four primary coils in
the spools F, are united by a cross wire-e' to a single wire which connects
through the switch-plug to a longer single wire ³, which, in its turn, is
connected to four short wires e, leading to the positive poles of the several
batteries L.
The batteries are all connected to the induction coils in the same manner and
direction, and the induction coils are all wound in the same direction relatively to
each other.
Referring to Figures 5 and 58, 0¹ and O' indicate the two parts which together
constitute the main body of the case of the receiving instrument. P is the
diaphragm of the receiving instrument. O is the front-piece, and O' the
mouth-piece, or rather the ear-piece to which the ear is applied to distinguish the
sounds. P is a diaphragm of soft iron. O³ is a check-nut or a threaded ring
adapted to be screwed down tightly against the edge of the part 0¹ when 01:
and O are rightly adjusted, and to hold them firmly in that adjustment.
Qis a pinching-screw tapped through a boss formed on the part O¹ and
engaging gently on the scrow-threads of the part 02, induces sufficient friction to
hold the adjustment firmly. A smooth or threadless place may be produced on the
part 0 to receive the point of this screw Q, if preferred.
The diaphragm P is held by its edge between the parts O¹ and 0%. An annular
bead O is formed on the inner or back face of the part 03 arranged to grip the
diaphragm P along a narrow line. This gives the diaphragm unusually clear
action. It sharply defines the portion which is left free to vibrate, analogous to
the frets on a guitar to receive the strings as they are pressed down at the different
points by the fingers. The annular bead O", seizing the diaphragm between itself
and the adjacent surface of 01, leaves the diaphragm perfectly free out to a certain
line and then definitely and firmly holds it. The ordinary means of clamping
diaphragms leaves a margin of doubtful or limited freedom which this construction
avoids.
R is a permanent magnet, straight and cylindrical, R' R' are collars thereon
near-the front end. The space between serves as a spool on which is wound a mass`
of covered wire.
T is a permanent magnet in the form of a hollow cylinder. Its interior has a
diameter a little greater than the collars R¹ R². On the exterior of T are two
collars TT, between which are wound a number of convolutions of wire t. This
wire & is electrically connected by soldering or otherwise to the wire r, and is

page_text: wound the same way, the outer end of the coil r being united to the-inner end of
the coil t.
;
The inner end of the coil r connects by a wire r¹ to a binding post W which
connects to the wire leading to the ground. The outer end of the coil
connects by a wire t¹ to the binding post X, which connects to the line wire M.
S is a cross-bar fitting tightly in holes bored or otherwise produced both in tho
exterior hollow magnet T and in the inner magnet R. It holds the two magnets
in their exactly correct positions axially, relatively to each other. V is a screw
inserted through the centre of the end of the back-piece 02. It is tapped into the
inner magnet R, and on being set up tightly draws the center magnet R forcibly
back, producing a strain on the cross-bar S. This construction holds both magnets
very rigidly to each other and to the front-piece O' and allows both magnets to be
reliably adjusted by a single movement turning the back-piece O within the
front-piece O' with their screw-threads engaged as shown,
Having thus described my invention and in what manner the same is to bo
performed, I claim as my invention the following improvements in telephones:
First: In a telephone, the method of communicating simultaneous vibrations to
a series of separate pins E by means of the rigid concave disc B¹ fixed to a point in
the vibrating disc B, substantially as herein described in reference to to Figs. 2
and 3 of the accompanying drawings.
Second-In a telephone, the set of independent devices E J with suitable
electrical connections, as d e, in combination with each other and with the singlo
operating device B B' for receiving and communicating thereto the vibrations
produced by the voice, substantially as herein described in reference to Figs.
1 and 6.
Third: In a telephone, the method of communicating over a single wire by a
series of independent telephonic devices mounted on arms holding them in close
proximity near the centre of the diaphragm, substantially as herein described in
referenco to Figs. 1, 2, 3, 4 and 6 of the accompanying drawings.
Fourth-In a telephone, the use, in combination with a single wire, as M, of a
series of independent telephonic devicos, as E J, actuated by a single impulse of
the voice communicated directly,. substantially as described in reference to Figs
1, 2, 3, 4 and 6 of the accompanying drawings.
Fifth-In a telephone, the use of a single wire and single switch for putting on
and taking off a series of local batteries, each connected with separate induction
spools and controlled by separate telephonic devices, substantially as herein
described in reference to Fig. 6 of the accompanying drawings.
Sixth-In a telephone, the use of a single ground connecting wire, as f¹, in
combination with a series of separate induction wires f h, separate induction
spools F, and independent telephonic devices E J for cach, substantially as herein
described in reference to Fig. 6 of the accompanying drawings.
Seventh-In a telephone, the series of independent arms D, carrying each a
separate telephonic device EJ and suitable connections, in combination with the
fastenings D insulators D³ and ring D³, substantially as described in reference to
Figs. 1, 2 and 3 of the accompanying drawings.
Eighth-In a telephone, the cylinders G carrying the carbon powder J engaging
by screw-threads in the arms D, so as to allow the adjustment to be effected by
turning the cylinder, substantially as herein described in reference to Figs. 2 and 3
of the accompanying drawings.
Ninth-In a telephone, the arms D fastenings D' insulators D' and ring D³, in
combination with the cylinders G carrying electrodes E J, and with the vibrating
dise B carrying the rigid piece B', substantially as herein described in reference to
Figs 1, 2, 3 and 4 of the accompanying drawings.
Tenth-In a telephone, the hollow magnet T in combination with the cross-
bar S and the interior magnet P, and a coil of wire on each, connected together
and leading to line, substantially as herein described in reference to Fig. 5 of the
accompanying drawings.

page_text: i
Eleventh-In a telephone, the method of. adjusting and maintaining the
adjustment of the receiving instrument, by turning one part relatively to the other
and firmly securing the position of the parts when 'adjusted, substantially as herein
described in reference to Fig. 5 of the accompanying drawings.
In Witness whereof I, the said Webster Gillett have 'herounto set my hand and
seal this 22nd day of September in the year of our Lord 1883.
WEBSTER GILLETT (L.S.)