Improvements in Telephone Transmitters and the Methods adopted for the Transmission of Articulate Speech, Musical and other Sound Waves.
Year: 1891

page_text: Date of Application, 20th Aug., 1891
Complete Specification Left, 19th May, 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Telephone Transmitters and the Methods adopted
for the Transmission of Articulate Speech, Musical and other
Sound Waves.
We, HERBERT LUZERNE TODD and JOHN TODD of Nos. 13 & 14 King Street,
Cheapside, in the City of London, Electrical Engineers, do hereby declare the
nature of this invention to be as follows:-
Our improvements in telephone transmitters consist of a diaphragm attached by
its centre to a flexible attachment secured or fixed to the transmitter case in such
form or manner as to allow of easy vibrations of the diaphragm in order to produce
the proper transmission of articulate speech without the aid of additional parts for
adjustment.
In order to attain this object we use a special construction of carbon pencil or
rod which may be either plain, fluted, cored or corrugated, connected by additional
parts to the periphery of the diaphragm, the object being to take up the vibrations
of the diaphragm and transmit the same electrically by a wire or cable.
The operation of our improved transmitter is as follows:-
The sound waves striking against our improved diaphragm radiate outward and
are taken up by the pieces, parts or attachments and agitate the carbon rod.
The wave sounds or vibrations are transmitted electrically by the current
produced from the battery, thermopile, or other suitable generator used in com-
bination therewith being conveyed by the circuit or conducting wire to and through
the specially constructed carbon rod and attachments as herein before described as
and for the purpose named.
At the same time that these vibrations are passing over the different attachments
of the before described parts as fitted in combination with our improved transmitter
the specially constructed flexible piece or attachment as arranged prevents the
harsh sounds of the voice which hitherto have been so detrimental in other systems
of telephony.
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1001
HERBERT LUZERNE TODD.
JOHN TODD.
Tongue & Birkbeck,
34, Southampton Buildings, London, W.C., Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Telephone Transmitters and the Methods adopted
for the Transmission of Articulate Speech, Musical and other
Sound Waves.
We,
HERBERT LUZERNE TODD & JOHN TODD of 13 and 14 King Street,
Cheapside in the City of London, Electrical Engineers, 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 :-
Our improvements in telephone transmitters consist of a diaphragm attached by
its centre to a flexible attachment secured or fixed to the transmitter case in such
form or manner as to allow of easy vibrations of the diaphragm in order to produce
the proper transmission of articulate speech without the aid of additional parts for
adjustment.
In order to attain this object we use a special construction of carbon pencil or

page_text: rod which may be either plain fluted cored or corrugated connected by additional
parts to the periphery of the diaphragm the object being to take up the vibrations
of the diaphragm and to transmit the same electrically over a wire.
When we use a cored carbon-the core is of metal or semi-metallic substance or
any other low resistance conductive 'material such as copper, aluminium, iron or
compounds of same.
The operation of this transmitter is as follows:-
The sound waves striking against our improved diaphragm radiate outward and
are taken up by the pieces parts or attachments and agitate the carbon rod.
The wave sounds or vibrations are transmitted electrically by the current
produced from the battery thermopile or other suitable generator used in com-
bination therewith being conveyed by the circuit or conducting wire to and through
the specially constructed carbon rod and attachments as hereinbefore described as
and for the purposes named.
At the same time that these vibrations are passing over the different attachments
of the before described parts as fitted in combination with our improved transmitter
the specially constructed flexible piece or attachment as arranged prevents the
harsh sounds of the voice hitherto so detrimental in other systems of telephony.
In Figures 1 and 2 a represents a diaphragm of any suitable material attached
at or near its centre to a flexible piece b the said flexible piece b being attached
or fixed to a circular ring h or it may be fastened to the rear of the case front.
Attached to the diaphragm a are two pieces d fastened at or near the periphery
of the diaphragm. These pieces d may be of carbon or they may be of wood with
carbon pieces attached thereto or with brass or with any other suitable metal for
the purpose of sustaining carbon pieces or non-oxidising metallic pieces. The
pieces d form the supports for the carbon rod or rods ƒ with their connecting
pieces e.
These pieces e are fixed permanently either to the pieces d or the rod but not
to both. If fixed permanently to the pieces d then they are fitted loosely in the
rod but if they are permanently fixed to the rod f then they are fitted loosely in
the pieces d-the object being to allow of a free movement of the rod f.
Attached to the pieces are screws g for the purpose of connecting the
transmitter to the line and battery respectively.
The flexible piece b may be made of any flexible material either wood or metal
or a combination thereof or of any other suitable material or materials that will
sustain and hold in place the diaphragm a the object being to sustain the
diaphragm a and by the flexibility of the said piece b to tone down the excess of
vibration of the diaphragm a which has heretofore caused a rattling sound as well as
other disagreeable noises so largely present in other transmitters and further by
use of this flexible piece b doing away with extra parts for such purposes.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that
what we claim is :-
1. A transmitting telephone with a flexible piece supporting a diaphragm at its
centre sustaining a carbon rod substantially as described.
2. A transmitting telephone consisting of a diaphragm connected at its centre to
a flexible piece fastened to a circular ring and sustaining a carbon rod substantially
as described.
3. A transmitting telephone with a carbon rod attached to a diaphragm which
is connected to a flexible piece fastened to a circular ring substantially as
described.
4. A transmitting telephone consisting of a diaphragm of circular or any other
suitable shape or material fastened at or near its centre to a flexible piece said
flexible piece to be attached to and form part of a frame to sustain it to a case as
.described.
5. The method of fixing the several parts and attachments for working in

page_text: combination with each for the production of clear articulate sound waves as and for
the purposes named.
6. The use and application in telephones of a cored carbon rod arranged and
constructed and acting substantially in the manner and for the purposes hereinbefore
described.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.