Improvements in Telephone Receiving Instruments.
Year: 1891

page_text: Date of Application, 13th Feb., 1891
Complete Specification Left, 10th July, 1891-Accepted, 15th Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in Telephone Receiving Instruments.
I, ERNEST JULES PIERRE MERCADIER of 1 Boulevard Saint Denis, Paris
France, Engineer, do hereby declare the nature of this invention to be as
follows:-
The essential qualities of a telephone, the intensity and the clearness of the
reproduction of the voice, depend not so much upon the dimensions of the telephone
as upon a proper proportion between the intensity of the field, the diameter of the
diaphragm and the thickness of the diaphragm. Having the above in view I have
already made telephones of reduced dimensions producing effects at least equal to
those of ordinary telephones in intensity, and superior in quality, that is to say as
regards the good reproduction of speech with its tone and variations. The present
invention has reference to these telephones of reduced dimensions.
I have also made these reduced telephones still lighter by substituting for the
metallic box a box of ebonite which owing to its insulating properties has the
further advantage of preventing derivations into induced currents. Having thus
reduced the weight to two ounces or less while improving the acoustic qualities of
the telephones, construct the instruments so that they can be held to the ears
without the assistance of the hands.
With this object I according to the present invention provide these reduced
telephones with nipple-like protuberances of wood or ebonite to enter into the ears,
and I connect together the instruments of each pair by means of a metallic spring
of approximately V-form. The ebonite box is composed of a central part or body
screw-threaded externally, a bottom and a cover; it contains the reduced parts of
a telephone of any kind. Upon the cover is screwed the nipple-like protuberance
of ebonite or wood, and in order to ease the friction of the protuberance against
the sides of the passage of the ear I cover the protuberance with a shield of
caoutchouc which is provided with a flange or ring to close the ear more hermetically
and thereby exclude external noise. Upon the central part of each telephone a
metal ring is screwed having two lugs or similar contrivances to which the V-spring
is attached. Upon these lugs I can if desired fix an aluminium wire which passes
over the ear. This wire is not really necessary, but it assists in supporting the
instruments.
If it is only desired to make use of a single receiving instrument the end of the
V-spring which has not an instrument attached thereto is provided with a pear
shaped piece or pad of india rubber to ease the friction of this end against the
cheek, and in order to prevent slipping an aluminium wire fixed to the spring and
passing over the ear will be very desirable.
The V-spring passes under the chin and is covered with a thin tube of caoutchouc
or other analogous material to reduce the noise arising from the rubbing of the
metal against the clothes. Its object is to apply to the instruments which are held
inside the ears by means of the protuberances a pressure which each operator can
diminish or increase by more or less separating the two arms of the V.
Instead of being fixed to a ring as hereinbefore described the V-spring can be
screwed to the cover or even to the magnet of the telephone. It can be of steel-
and be magnetised and thus serve to increase or at any rate maintain the magneti-
sation of the telephones; it can also serve for electrical connection between the two
instruments which would then have a supple cord with one conductor instead of
two conductors.
With regard to the nipple-like protuberances they have the further advantage

page_text: from an acoustic point of view of bringing the sounds received as near as possible
to the membrane of the tympanum.
By means of this simple combination of the protuberances and of the spring
applied to light receiving instruments it will be possible henceforth to telephone
without inconvenience and with the hands free. The operators are thus free to
write the messages which they receive and transmit, or take notes during con-
versations; and the attendants at central offices can work with the hands the
apparatus by which they effect the desired communications.
Dated this 13th day of February 1891.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Telephone Receiving Instruments.
I, ERNEST JULES PIERRE MERCADIER of 1 Boulevard St. Denis, Paris,
France, 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 :-
The essential qualities of a telephone, the intensity and the clearness of the
reproduction of the voice, depend not so much upon the dimensions of the telephone
as upon a proper proportion between the intensity of the field, the diameter of the
diaphragm and the thickness of the diaphragm. Having the above in view I have
already made telephones of reduced dimensions producing effects at least equal to
those of ordinary telephones in intensity, and superior in quality, that is to say as
regards the good reproduction of speech with its tone and variations: The present
invention has reference to these telephones of reduced dimensions.
I have also made these reduced telephones still lighter by substituting for the
metallic box a box of ebonite, which owing to its insulating properties has the
further advantage of preventing derivations into induced currents. Having thus
reduced the weight to two ounces or less while improving the acoustic qualities of
the telephone I construct the instruments so that they can be held to the ears
without the assistance of the hands.
With this object I according to the present invention provide these reduced
telephones with nipple like protuberances of wood or ebonite to enter the ears, and
I connect together the instruments of each pair by means of a metallic spring of
approximately V-form, the two instruments thus connected constituting what may
properly be called a bitelephone.
The annexed drawing will serve to illustrate the invention. The ebonite box is
composed of a central part or body B screw threaded externally, a bottom F and
a cover C; it contains the reduced parts of a telephone which may be of any
suitable kind. Upon the cover is screwed the nipple-like protuberance T of ebonite
or wood and in order to case the friction of the protuberance against the sides of
the passage of the ear the protuberance can be covered with a shield of caoutchouc
having a flange or ring to close the ear more hermetically and thereby exclude
external noise. Upon the central part of each telephone a metal ring O is screwed
having two lugs or similar contrivances a a¹ to which the V-spring V is attached.
Upon these lugs I can if desired fix an aluminium wire which passes over the ear.
This wire is not really necessary but it assists in supporting the instruments.
If it is only desired to make use of a single receiving instrument the end of the
V-spring which has not an instrument attached thereto is provided with a pear
shaped piece or pad of india rubber to ease the friction of this end against the
cheek and in order to prevent slipping an aluminium wire fixed to the spring and
passing over the ear will be very desirable.
The V-spring passes under the chin and is covered with a thin tube of caoutchouc
or other analogous material to reduce the noise arising from the rubbing of the

page_text: metal against the clothes. Its object is to apply to the instruments which are held
inside the ears by means of the protuberances a pressure which each operator can
diminish or increase by more or less separating the two arms of the V.
Instead of being fixed to a ring as hereinbefore described the V-spring can be
screwed to the cover or even to the magnet of the telephone. It can be of steel or
soft iron and be magnetised and thus serve to increase, or at any rate maintain the
magnetisation of the telephones; with this object the spring V is connected at each
end by steel plates R to the magnetised core Ñ of the electro magnets with the aid
of the screws A and nuts E. The V-spring can also serve for electrical com-
munication between the two instruments which would then have a supple cord with
one conductor instead of two conductors; for this purpose one end of the wire of
the coil of the electro magnet is connected to the metal ring O by screws and
therefore put in connection by the screw A with the spring V.
With regard to the nipple-like protuberances they have the further advantage
from an acoustic point of view of bringing the sounds received as near as possible
to the membrane of the tympanum.
By means of this simple combination of the protuberances and of the spring
applied to light receiving instruments it will be possible henceforth to telephone
without inconvenience and with the hands free. The operators are thus free to
write the messages which they receive and transmit, or take notes during
conversations; and the attendants at central offices can work with the hands the
apparatus by which they effect the desired communications.
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 a telephone receiving instrument, a nipple-like protuberance (covered or
not with caoutchouc), to enter the ear and serving not only to support the
instrument but also to bring the sounds received as near as possible to the
tympanum, substantially as hereinbefore described with reference to the annexed
drawing.
2. The combination with nipple-like protuberances as referred to in Claim 1 of
a V-shaped spring connecting two receiving instruments substantially as and for
the purpose hereinbefore described with reference to the annexed drawing.
3. The employment of the said V-spring to establish electrical communication
between the two instruments and to increase or maintain their magnetisation
substantially as hereinbefore described with reference to the annexed drawing.
4. The improved telephone receiving instrument or bitelephone herein before
described and represented in the annexed drawing.
Dated this 10th day of July 1901
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.