Improvements in and connected with Telephonic Apparatus.
Year: 1894

page_text: Date of Application, 28th Aug., 1894-Accepted, 24th Aug., 1895
COMPLETE SPECIFICATION.
Improvements in and connected with Telephonic Apparatus.
We, JULES CERpaux, and GeoRGES DE L'ESCAILLE, Electricians, both of
3 Rue d'Artois, Brussels in the Kingdom of Belgium, 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 invention consists of a very simple and cheap telephonic apparatus for
communications in combination with a system of bells.
Our system consists of two parts, the microphone and the commutator or
indicating tablet. The telephone is hung on the hook of a special microphone
constituted of a series of carbon pencils resting at their extremity in graphite
bearings applied against the vibrating plate of the microphone; by their position,
as shown in the drawing, these pencils are not liable to cause a "frying" sound
which interferes more or less with the sound of the voice.
To the microphone is attached a small induction bobbin, serving to avoid the
general "frying" sounds and to strengthen the power of the voice, in consequence
of which this latter is no longer attenuated by false sounds, and by the addition of
the said bobbin, the current conducting the voice is no longer a direct current but
an indirect current as the line wire passes through the bobbin. A competent
person, on examining the drawings and diagrams accompanying this Specification,
will readily follow the course of the currents. The contact by the hook when the
telephone receiver is hung on the microphone completes the circuit for the bell
mechanism by passing through the central terminal, whilst if the telephone receiver
is removed for use, the circuit of the bell mechanism is broken and the spring
detent or hook upon which the telephone is ordinarily hung, moves against a
contact which forms a telephonic circuit, consequent on its being placed in
connection with the line wire. Thus, therefore, the same line which serves for a
bell mechanism, serves also for the telephone by a simple change of contacts
which renders the line wire pole negative whilst before it was the line wire.
This special combination of telephone upon the conductor of a bell mechanism,
naturally required an arrangement of commutator or indicating tablet, which we
have arranged as follows. This indicating tablet, which must not be confused with
others of Cerpaux's manufacture, is composed of a plate of copper or other
material being a conductor of electricity; this plate is combined with a number
of commutators serving to open or close a circuit, in consequence of the line
wire conductors of the bell mechanism being in relation with this plate, which
in the normal condition remains pole negative. This plate serving as contact
is provided with commutators of equal number, plus one, to the number of com-
munications which branch off therefrom. This plate forms the cover of th
indicating tablet or commutator, which has the appearance of a box; the bottor,
of this box, or the side opposite to the said plate, is of dry wood and ebonite. B
pushing one of the commutators it intercepts the annunciating current, which
becomes a negative current passing through the copper plate and through the wir
leaving the said plate which corresponds with the negative; this therefore cause
the line wires to be derived and in lieu of being lines they become negatives, >>
that speaking can take place at one or several places at the same time, according
as one or several commutators are operated.

page_text: And in order that the invention may be clearly understood, we will describe the
same with reference to the accompanying drawings, in which
Fig. I represents a front view of the combined apparatus.
Fig. II is a side view of the same.
Fig. III is a plan of the indicating tablet.
Figs. IV to XI represent another arrangement or modification following the
same principle and to which we will refer later on.
In this modification Fig. IV is a vertical transverse section, Fig. V is an internal
view, Fig. VI is a front view, Fig. VII is a side view and Fig. VIII is a plan or
top view of the microphone and Fig. IX is a front view, Fig. X is a plan or top
view and Fig. XI is a back view of the indicating tablet.
Fig. XII is a diagram showing the course of the current when the bell is
in use, and
Fig. XIII is a diagram showing the course of the current when the telephone is
in use.
As will be seen at Fig. I the box A, containing and carrying the commutating
organs or parts of the apparatus, is surmounted by two columns B, which embrace
and support the microphone C and the two telephone receivers D. This forms a
very convenient, and at the same time an elegant, arrangement.
Communication is effected upon the indicating tablet or box of commutators by
introducing a key or pin into one of the holes a a a corresponding with the
relation which it is desired to establish. By pushing the pin or key into the
hole, a spring plate a¹ is depressed, which latter consequently establishes contact
by pressing against a counter plate a² to which the wire is connected, see Fig. XI.
The two telephone receivers D being unhooked, the apparatus works in the
ordinary way.
"
The microphone is very sensitive and the carbon pencils E, which can be made
more or less long according to the intensity of voice it desired to obtain, are
without reciprocal effects the one with respect to the other, so far as the "frying
sound is concerned, as they have each their particular or individual support, see
Figs. 1V and V. These supports are formed of graphite rings F having a flat on
their periphery to cement them to the vibrating plate of the microphone. These
rings have each a central opening through which the pencils pass. The ends of
these latter rest against two small squares or pieces of sufficiently strong paper
cemented also to the plate of the microphone in such manner as to embrace the
series of pencils and hold them lightly between them. The association of the
squares or pieces of paper combined with the pencils, and the combination of
the pencil supports have the result of eliminating all "frying" sound and of
rendering the microphone very sensitive. Each pencil is further provided for this
purpose with a small sleeve H of caoutchouc intended as a sound damper.
G
The spring detent or hook I, see Fig. 5, passes through a clot in the side of the
telephone box and is mounted on a bracket J fixed in the interior of said box.
A spiral tension spring K connected at one end to the hook I and at the other
end to a pin or screw fixed to the box, or other equivalent spring, serves to bring
the hook I always to its highest position unless prevented by the weight of the
telephone receiver hanging on it.
The book I is provided with a contact pin L, which, when the telephone receiver
is hanging on the hook, is in contact with a lower spring contact M'in connection
with the bell through the terminal marked 3, but when the telephone receiver is
taken off the hook I, the latter will rise as already stated and bring the contact
pin L into contact with the upper spring contact N in connection with the line
through the terminal marked 2.
Referring to the diagrams Figs. XII and XIII representing the courses taken
by the current, it will be seen at Fig. XII that when the telephone receiver D is
hanging on the hook I, thereby depressing the latter and bringing its contact pin L
into contact with the lower spring contact M as shown in dotted lines at Fig. V,
the current passes, in the direction of the arrows, from the line through the bell

page_text: which latter is kept ringing so long as the receiver is on its hook.
When the
receiver is taken off its hook, the latter, under the influence of the spring I, will
rise to its highest position and thereby, while breaking the bell connection, will
establish telephonic connection and cause the electric current to follow the direction
of the arrows in Fig. XIII.
Our invention, according to the form represented at Figs. IV to XI, can also be
applied in another manner or as a simple ordinary telephone; in this case the
indicating tablet, which forms a table or stand in the arrangement shown at
Figs. I, II and III, is placed separately below or above the telephone and carries
the openings for the key under or above each figure representing the communi-
cation it is desired to establish.
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. The combination of telephone with an electric bell apparatus, substantially
as herein shown and described and for the purpose stated.
2. In telephonic apparatus, the very sensitive microphone having carbon bearings
to carry the carbons, these bearings being separate for each pencil, substantially as
herein shown and described and for the purpose stated.
3. In microphones for telephonic apparatus, the employment and application of
squares or pieces of paper projecting from the plate of the microphone upon which
they are cemented, these squares or pieces of paper being intended to receive (by
simple friction), and to hold between them, the carbon pencils of the said microphone,
provided with a sleeve of caoutchouc forming a sound damper to obviate "frying
sounds, substantially as herein shown and described.
"
4. The improvements in and connected with telephonic apparatus substantially
as herein shown and described and for the purpose stated.
1
1004
JULES CERPAUX,
GEORGES DE L'ESCAILLE,
By Harris & Mills,
23 Southampton Buildings, London, W.C., Agents.