Improvements in Telephonic Apparatus.
Year: 1896

page_text: Date of Application, 16th June, 1896-Accepted, 5th Dec., 1896
COMPLETE SPECIFICATION.
Improvements in Telephonic Apparatus.
CHARLES ADAMS-RANDALL of No. 1 The Avenue Bedford Park London W.
England, Electrical Engineer 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 :-
This invention relates to improvements in telephonic apparatus whereby I am
enabled to utilize a current of suitable power from a battery or other source of
electricity for the transmission of articulate speech over a distance the length of
which corresponds to the electric power utilized.
The characteristic feature of my invention is to use any suitable number of
batteries in order to sufficiently intensify by means of my improved electric
transmitter the articulate sounds required to be transmitted so as to be able to
telephone over long distances, such distance being practically unlimited so long as
an unlimited number of batteries are provided and are intercalated according to my
invention, into a telephonic, telegraphic or other circuit, without any whistling,
sparking or other detrimental effects occurring at the transmitter.
In the accompanying drawings, wherein like letters of reference indicate corre-
sponding parts, Fig. 1 is a diagrammatic view illustrating the manner in which my
invention is carried into practice. Fig. 2 is a cross section on line of Fig. 1 of
the said transmitter, whereby four batteries or one battery divided into four sections
can be intercalated in the circuit. Figs. 3 and 4 are a plan and a cross section
respectively of another form of transmitter whereby one battery only is intercalated
in the circuit.
In Figs. 1 and 2, the numeral 1 represents a case, preferably of vulcanite, movably
secured to the front or lid of a box 2 by means of spring contacts 3-3-3-3
bearing on the metal spring arms 4-4-4-4 secured by screws 4' to the case 1.
An arm 5 for supporting the telephone receiver being also secured to the case 1,
such arm being movable, with the said case, to and fro between fixed stops 6-7 by
reason of the weight of the receiver when suspended to the arm 5* in one direction
and by the spring 8 in the opposite direction; such movement of the arm and of
the telephone transmitter serving to connect and disconnect the spring contacts 3,
the spring arms 4 and the usual line connections.
To the spring arms 4 are secured by screws 411 the electrodes of the
microphone 5-5 (shown in Fig. 2) which pass through openings in the top of the
case 1 and the soft perforated pad or cushion 9 secured to the case 1, the pad
projecting beyond the electrodes 5 and against the diaphragm 10 which is held in
place by the supporting springs 10, 10 and the adjusting ring o fitted movably in
the thread formed in the case; a chamber being formed around the electrode and
between the latter and the diaphragm 10 containing granulated carbon or other
suitable material 11. The granules are partly contained within the electrodes and
partly surround the same, the granules between the electrodes and the diaphragm
being confined under pressure by the spring arm 4 which is adjustable towards the
diaphragm by the screw 12, the granules surrounding the electrodes making a light
normal contact by gravity whereby a desired contact may be obtained between the
diaphragm granules and the electrodes by pressure and simultaneously therewith a
light normal contact produced between the same parts by the loose granules
surrounding the electrodes, so that the rupture of the circuit sparking" and harsh

page_text: noises or imperfect articulation is prevented and the conducting and varying of the
total current of the battery or thereabouts is practically obtained.
D is the battery comprising, in the example illustrated 12 cells divided into four
sections, a connection being made between the similar pole of each section and the
spring arms 4 corresponding to a similar section of the transmitter; the current
passing from the different battery sections to the spring arms 4 and the electrodes 5
carried thereby to their granules and diaphragm and thence by a single return
wire 10 back to the battery. A key or circuit breaker 14 may be included if
desired for calling or signalling purposes.
One of the features of my invention is the use of one or more induction coils in
combination with a transmitter and I prefer to use as many induction coils in the
primary circuit with the battery and the transmitter as there are sections of the
transmitter, but it will be understood that a single transmitter may have any
number of sections, the same being limited only to the diameter of the diaphragm
and the size of the electrodes.
I have shown three methods of connecting the induction coils in circuit with the
induction coils transmitter and battery marked A, B, C respectively. Under A
the primary convolutions of the several induction coils e, e, e, e are arranged in
circuit between the sections of the battery D aud the transmitter, the current
passing from the battery over the primary convolutions, and the several
electrodes, granules and diaphragm, thence by the single retura circuit 10° back
to battery.
Under B and C the primary convolutions of the induction coils are arranged in
the single return circuit 10° and connected in series under B and in parallel under C.
The circuit under B being from the sections of the battery to the sections of the
transmitter direct (c, e, e, e being removed) and thence over wire 15, wire 16,
induction coils e ele el, wire 17, key 14, wire 10 back to battery. The circuit
under C being as in B from the battery to the transmitter, thence to wire 15,
wire 19, induction coils cc", cl, cll wire 21, key 14, wire 10° back to battery.
The secondary wires of the induction coils may be connected up in either case, in
series or in parallel, or in parallel series. One important feature of my invention
consists in providing means for readily changing the resistance of the circuit at
will, by cutting out the resistance of one or more or all the induction coils at the
receiving station, when receiving messages. In Fig. 1, I have shown one manner
of accomplishing this, and the circuits therefor. This feature of my invention
consists generally of a switch or circuit changer arranged preferably upon the
handle of a telephone receiver, so as to be readily operated by one ánger when
holding the receiver in the hand. In the receiver R shown on the right hand side
of Fig. 1, 22 is a permanent magnet having a soft iron core 23 secured thereto and
upon which is wound a coil 23; a diaphragm 24 being likewise provided a hook 25
is attached to the receiver for suspending same on the arm 5. The magnet 22 is
enclosed in a suitable handle 26 upon which is secured, insulated one from the
other, a spring switch 27 and the contacts 28 and 29.
As clearly shown, the receiver is in the main line circuit with the induction
coils el, one end of the secondary convolutions of which is connected to earth E and
the other end to the contact piece 28 by the wire 32, the switch 27 being connected
to the main line L, this being the arrangement and position of parts and circuits
when transmitting. When receiving messages, however, the switch 27 is depressed
to make contact with the piece 29, the circuit being then from L, over coil 23 to
switch 27, point 29, wire 30, over one induction coil, to earth E, thus cutting out
three induction coils, or from wire 30 by means of wire 31, to earth E, thus
cutting out all the coils.
Fig. 3 is a plan of a single section transmitter and Fig. 4 is a sectional view
thereof. The construction of this transmitter is similar to that above described
two recesses being formed in case 1 through which pass, the retaining screws
movably holding the transmitter in place. An arm 5 is secured to the case and is
actuated by the spring 8 as well as the case 1 in one direction, while a suitable

page_text: weight such as a telephone receiver placed on the said arm carries it in the opposite
direction, by which action or movement the circuit from the battery is closed and
broken at the spring 3 and the contact piece 3°.
The mouth piece P of the transmitter T Fig. 2 is of special construction being
provided, at or near the orifice, with a circular channel or gutter of larger
diameter than the latter, in order to entrap the condensed moisture from the
breath and prevent the same from trickling outwardly and inwardly, this moisture
being readily removed.
It will be easily understood that a non conducting diaphragm of mica, wood or
cork carrying an electrode attached thereto, arranged opposite the several
electrodes and in electric contact therewith and the return circuit may be used
in some cases in place of the diaphragm of conducting material as hereinbefore
described.
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 telephonic transmitting apparatus, the combination of two or more separate
electrodes or contacts, a diaphragm or vibrator opposite the electrodes and in
electric contact therewith while actuating the same, two or more induction coils
having their primary convolutions connected to different sections of the transmitter
and to independant batteries or to different sections of one battery, while their
secondary convolutions are in the main line circuit, the diaphragm being connected
to the return circuit of the battery or batteries, with means for automatically
switching the said battery or batteries in and out of the circuit, substantially as
berein described and shown at A Fig. 1.
2. In telephonic transmitters, the combination of two or more separate electrodes
connected respectively to separate batteries or to different sections of a battery, a
diaphragm opposite to and in electric contact with the electrodes and actuating the
same, a single return circuit from the diaphragm to the battery or hatteries
including one or more induction coils having their primary convolutions connected
in series, while the secondary convolutions are included in the main circuit,
substantially as herein described and shown.
3. In telephonic transmitters, two or more independant electrodes arranged
opposite to and in electric contact with the diaphragm, adjustable means for
obtaining the proper pressure contact between the diaphragm and the electrodes,
more induction coils having their primary convolutions connected in
parallel in the return circuit with the transmitter and two or more independant
batteries or different sections of one battery, together with suitable circuit and
line connections, substantially as herein described and shown at C in Fig. 1.
4. In telephonic transmitters, the combination with a diaphragm of adjustable
means for supporting and securing the same under proper tension, one or more
resilient electrodes opposite the diaphragm but not in contact therewith, a ring or
perforated pad of suitable soft material surrounding the electrode or electrodes but
independant of the same, against which the diaphragm may be pressed, granulated
carbon interposed between the diaphragm and the electrode or electrodes and
adjustable means for obtaining a flexible pressure-contact between the electrode or
electrodes, the granulated material and the diaphragm, substantially as berein
described and shown.
5. In telephonic transmitters, the combination with a diaphragm of suitable
means for supperting the same, oue or more partly tubular or concave resilient
electrodes arranged opposite the diaphragm, a ring or perforated pad of soft
material secured independently of the diaphragm and electrodes but surrounding
the latter, granulated carbon interposed between the diaphragm and the electrode
or electrodes, part of which loosely surrounds the same, with adjustable means for
obtaining the flexible pressure-contact between the diaphragm, the electrode or
electrodes and the granulated material, whereby a contact is established between

page_text: the same by means of the loose granules surrounding the electrodes, substantially
as herein described and shown and for the purpose set forth.
6. A telephonic transmitter having in combination two or more independant
electrodes 5 secured to an adjustable spring 4, a suitable adjuster 12, a ring or
perforated pad 9, granulated material 11 and a diaphragm 10 constructed and
arranged substantially as herein described and shown.
7. A mouthpiece for telephonic transmitters constructed and arranged substan-
tially as herein described and shown.
8. In combination. with a telephonic transmitter the use of one or more
induction coils with means for readily switching the said coil or coils out of
the circuit in order to reduce the resistance, substantially as herein described and
shown.
9. In combination with a telephonic transmitter, a telephonic receiver provided
with a main line switching device or "cut-out" substantially as herein described
and shown.
10. In combination with a telephonic transmitter, one or more induction coils
having their secondary couvolutions in circuit with a telephonic receiver, a
switching device attached to or forming part of the receiver, circuit connections
to the induction and to the receiver coil or coils and the switching device whereby
the said induction coils can be readily switched in and out of the circuit,
substantially as herein described and shown.
11. In a telephonic transmitter a case containing or carrying the transmitter
parts, arranged to be moveably held in place and provided with means for
obtaining a to and fro motion of the case, such motion serving to connect and
disconnect the circuit or circuits as and when required, substantially as herein
described and shown.
Dated this 16th day of June 1806