Improvements in Portable Telephonic Apparatus.
Year: 1893

page_text: Date of Application, 18th Apr., 1893
Complete Specification Left, 18th Jan., 1894-Accepted, 18th June, 1894
PROVIDIUNAL DUTIVATION.
Improvements in Portable Telephonic Apparatus..
GEORGE LEE ANDERS of 10 Jeffrey's Square E.C. Electrician, and WALTHER
KOTTGEN of 10 Jeffrey's Square E.C. Merchant do hereby declare the nature of
this invention to be as follows:
The object of the invention is to provide a portable microtelephone consisting
of a case containing the microphone and receiver, to which is attached an elongated
mouthpiece forming the handle of this portable telephone.
A portion of the mouthpiece is formed of a hollow soft iron tube through
which the sound waves pass and which constitutes. the inducing core of the
induction coil.
J
A 1902
GEORGE LEE ANDERS.
WALTHER KOTTGEN.
COMPLETE SPECIFICATION.
Improvements in Portable Telephonic Apparatus.
GEORGE LEE ANDERS of 10 Jeffrey's Square E.C. Electrician, and WALTHER
KOTTGEN of 10 Jeffrey's Square E.C. Merchant 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 electric telephones of that class which
consists of a microphone placed in the primary circuit, of an induction coil, and a
magneto telephone receiver. It consists mainly in the construction and arrange-
ment of these features to provide a portable or hand telephone in one convenient
and compact piece.
That part of these improvements which consists of an induction coil having a
tubular core and mouthpiece, is also applicable to those telephones which are
designed to be attached to the wall or upon a table, the receiving portion of which
is attached thereto by a flexible cord.
According to our invention we wind the primary and secondary wires of an
induction coil upon a tubular piece of soft iron, to one end of which we attach a
mouthpiece at right angles therewith, whilst at the other end of the tube, also at
right angles with it, we attach a small cylindrical case which is divided into two
chambers by a partition contained therein.
The side of the partition adjacent to the tube, contains the microphone, whilst
the opposite side of it carries the magnets and coils of the receiving device. This
partition in the cylindrical case prevents the air waves which pass from the
mouthpiece through the induction coil and on to the diaphragm of the microphone,
from reaching the receiving chamber and thus impinge on the ear of the
listener.
In the accompanying drawings which are to be taken as part of this
Specification
Fig. 1. is a diagrammatic section through the hand telephone ;
Fig. 2. is a similar drawing as constructed for microphones, not intended to be
held in the band.

page_text: Fig. 3. is a diagram of the automatic hook-switch contained in the case of the
microphone.
In Fig. 1. A represents an induction coil indicated by the dotted lines which is
wound upon the soft iron core or tube B. To one end of this tube B is attached
a mouthpiece C, at the other end of the tube is attached a cylindrical case D.
This case is attached to the tube B at right angles by a clamping ring E, which
firmly secures the different parts contained within the case D.
These parts are introduced as follows: First a diaphragm F which is secured in
position by the distance ring G. Then upon this distance ring G is placed a
partition plate H and before this plate H is introduced into the case, the permanent
magnets I and coils J are attached to it on the side adjacent to the diaphragm.
To the opposite side of this partition plate H is secured a recessed carbon block K.
The partition plate H having been placed as aforesaid, it is secured in place by a
second ring M of insulating material, and lastly upon this is placed a carbon
diaphragm L. The metal plate N is permanently attached to the tube B. This
plate N is encircled by a clamping ring E which is free to rotate therewith or
thereon, the clamping ring E provided with an inner thread on the case D by
which means the ring E can secure all the different parts contained within the
case D as well as the case itself to the tube B. The microphone consists of a
loose conducting material of carbonized fibre, which is introduced into the recess
of the block K, and rests between it and the carbon diaphragm L, and there is a
washer of soft and non-conducting fibre which serves to retain the carbonized
fibre within the block K. The case D is made of an insulating material such as
ebonite.
The operation of this apparatus is as follows:
When it is removed from an automatic switch (a well known device not shewn)
to speak to a distant station, or when a signal has been received from a distant
station, a current flows from the battery S, from one side to the terminal K and to
the primary wire Q, to the partition plate H and carbon block K, through the
carbonized fibre or microphone to the carbon diaphragm L, metal plate N, tube B,
terminal T, back to the opposite pole of battery S.
Any sounds or words spoken into the mouthpiece C will pass through the
opening of tube B and plate N and impinge on diaphragm L and will vary the
current passing through the microphone and primary wire Q, thus setting up an
induction current in the secondary wire, which passes from the partition H and
primary circuits to earth, while from the other end of the secondary wire it passes
to terminal O to the line wire W to operate the distant telephone.
Fig. 2 shows a section of a casing A enclosing an induction coil having a
mouthpiece B provided with an inductive tube of soft iron C.
The terminals D & E represent the extremities of the primary wire P, the
terminals F & G are those of the secondary wires S, all the foregoing parts are
mounted upon a face plate H which encloses a cylindrical box containing the
automatic hook switch L the microphone M and contact springs N, N', Nu in
Fig. 3. In this case the automatic switch is provided with an opening K as shown
in Fig. 3, so as not to obstruct the air_waves as they pass through the inductive
mouthpiece B to the microphone M in Fig. 2.
As all the parts within the cylindrical case enclosed by the face plate H (Fig. 2)
are well known, they need not be described in detail. It must be understood that
our invention consists in the combination of the annular inductive mouthpiece B
and its primary and secondary wires, with the microphone automatic switch etc.
contained within the cylindrical case.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A portable telephone the handle of which carries a microphone and receiver,
the handle constituting an induction coil consisting of a primary wire included in

page_text: the circuit of a local battery, the secondary of which excites the line current for
the purpose set forth.
2. An induction coil provided with a tubular inductive core in combination
with a mouthpiece as and for the purpose set forth.
Dated this 18th day of January 1894.
GEORGE LEE ANDERS.
WALTHER KOTTGEN.