Improvements in Transmitters for Electric Telephones.
Year: 1890

page_text: Date of Application, 14th Mar., 1890
Complete Specification Left, 11th Nov., 1890-Accepted, 27th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in Transmitters for Electric Telephones.
I CHARLES LIONEL WINGFIELD FITZ-GERALD of 109 Farringdon Road in
the City of London Chairman of the Consolidated Telephone Construction and
Maintenance Company Limited do hereby declare the nature of this invention to
be as follows:-
:-
My invention relates to transmitters in which granulated carbon is used and
its object is to provide transmitters which are more efficient than are those
hitherto proposed or used.
According to my invention I provide in a suitable holder discs or plates which
are preferably of carbon and I insulate these discs or plates from each other by
means of rubber or other insulating material at their edges. Across or in the
space between these discs or plates I provide a division of a curved or angular
form passing across the centre or thereabouts of the discs or plates and extending
from side to side so as to make at one side of the centre a space which preferably
is less than half the area of the discs or plates and in this space 1 place the
granulated carbon.
Dated this 14th day of March 1900
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.
COMPLETE SPECIFICATION.
Improvements in Transmitters for Electric Telephones.
I CHARLES LIONEL WINGFIELD FITZ-GERALD of 109 Farringdon Road in
the City of London Chairman of the Consolidated Telephone Construction and
Maintenance Company Limited 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 :-
My invention relates to transmitters in which granulated carbon is used and
its object is to provide transmitters which are more efficient than are those
hitherto proposed or used.
I will describe my invention with reference to the accompanying drawing
Figure 1 being a transverse section on the line 1, 2 Figure 2 and Figure 2 a
section on the line 3, 4 Figure 1.
According to my invention I provide in a case or holder A discs or plates b and c
which are preferably of carbon and I insulate these discs or plates from each
other by means of rubber or other insulating material at their edges as at d.
Across or in the space between the said discs or plates b and c I provide a
division E of a curved or angular form passing across the centre or thereabouts
of the discs or plates b and c and extending from side to side so as to divide
the area between the discs or plates b and c into two spaces c³ ³. In the space c³
I place the granulated carbon.
and are the connecting wires secured respectively to the discs or plates b
and c,
h is an india rubber ring between the disc or plate and the inner flange a
of the case or holder A.

page_text: 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,―
A telephone transmitter with the area between the two discs or plates b and c
divided by the partition E as described into two spaces so that the granulated 5
carbon is contained in one of the said spaces substantially as described.
Dated this 10th day of November 1890.
C. L. W. FITZ-GERALD.