Year: 1887

page_text: Date of Application, 16th Mar., 1887.
Complete Left, 28th July, 1887.
Complete Accepted, 30th Aug., 1887.
1, CHARLES CLAMOND of 15 Rue Picot, Paris in the Republic of France, Engineer
do hereby declare the nature of this invention to be as follows:-
The micro-telephonic instruments as at present constructed are of a bulky nature,
almost always necessitating the use of an induction coil; those which do not possess
this are wanting in energy in the transmission of speech, and their clumsy form prevent
their use in dwellings. My present invention has for its object the construction of a
micro-telephonic instrument without induction coil, that shall be of small dimensions
and shall transmit speech with the same degree of distinctness as those instruments
that have an induction coil. It is necessary for this purpose in the first place, that the
diaphragm should be in a vertical and not a horizontal position, as the latter arrange-
ment necessitates a considerable projection of the instrument from the face of the wall,
which gives it a clumsy appearance, as is the case with the "Crossley," "Ader,"
"de Maiche," "Gower-Bell" and other instruments, in which the microphonic contacts
are suspended below the horizontal plate that acts as diaphragm. On the other hand
those instruments that have been constructed with vertical diaphragms are rendered
equally cumbersome on account of the necessary devices for holding and regulating
the position of the contacts relatively to the vibrating plate.
The devices which I employ for the contacts according to my invention do not
require any regulation, so that I am enabled to construct such instruments of the
dimensions of about 34 inches in diameter, by about 1 inches in depth. Generally
speaking, any micro-telephonic instrument, in order to be able to transmit speech to
considerable distances with the same clearness and strength as the best telephones with
bobbins, must have microphonic contacts complying with the following conditions:
Firstly Their electrical resistance must be subject to considerable variations under
the influence of even feeble vibrations of the diaphragm; Secondly-Their electrical
restistance, when at rest, must always be practically equal, that is to say, it must sink
back to the initial value when the diaphragm ceases to vibrate. Thirdly-They must
never separate from the diaphragm to such an extent as to cause a break of contact
even under the influence of the strongest vibrations. These conditions are complied
with by my construction of microtelephonic instrument, which I will proceed to
explain.

page_text: My invention consists essentially in the use of a vertical carbon or other conducting
block having one or more cavities in its face the lower side or sides of which is or are
inclined downwards, and in these cavities are placed loose micro contacts in the form
of balls, cylinders, or other rolling body which consequently tend to roll down the
inclined sides and are thus always maintained in contact with the vibrating plate or
diaphragm situated in front of the carbon block, consequently establishing an electrical
contact between the two.
Thus when at rest, the pressure of the contact and consequently the resistance is
always the same namely that due to the weight of the rolling body upon the incline,
while on vibrations being established through speech, the displacement of the contacts
thereby is greatly facilitated by the rolling action thereof, as compared with the sliding
action of the contacts now employed, these causing greatly increased friction which
is detrimental to clearness and loudness of the sound transmitted.
In constructing a micro-telephonic apparatus on this principle I prefer to arrange it.
as follows.
The carbon or other conducting block with its recesses and rolling microphonic
contacts is mounted in the central hole of a disc of insulating material contained
in a metallic casing the front part of which forms a socket for containing the
telephonic receiver of ordinary construction when this is not in use. In front of
the conducting block and microphonic contacts is the vibrating plate or diaphragm,
insulated from the metal casing, and exposed to view when the receiver is drawn out
of its socket for use.
To the back of the insulating disc, and insulated from the conducting block is fixed
a conducting plate which is connected by a wire with one of the terminals of the
ordinary call bell. An elbow lever mounted on a pivot on the insulating disc has its
one arm extending horizontally over the socket of the casing terminating in an incline
which passes through a slot in the socket, so that when the receiving instrument is
inserted into the latter it moves the lever by pushing against the incline thereof and
thus causes its other arm which extends downward across the contact plate, to make a
contact with a spring on the latter so as to complete the circuit through the call bell,
so that any current passing will ring the latter. When the receiver is withdrawn from
the socket so that the horizontal arm of the elbow lever can fall somewhat, the other
arm is caused by a spring to break the call-bell circuit and establish contact
with a conducting stop that is in connection with the microphonic block, so that the
circuit of the latter is closed. Another contact spring, when pressed upon by a button,
is made to close the circuit of the call-bell at the distant station. According to another
modification instead of inserting the receiver into a socket on the transmitter as
described, it is hung on to the end of the elbow lever which is formed as a hook,
and this is thereby made to effect the contact with the call-bell circuit as described,
while when the receiver is lifted off, the lever is moved by a spring so as to close the
transmitter circuit.
In the before described arrangement of the microphone block, rolling contacts, and
diaphragm, instead of the rolling contacts resting directly against the diaphragm,
they may bear against a suitable conducting surface connected to the diaphragm
so as to vibrate therewith, also instead of being situated in inclined cavities in the
block, the rolling contacts may be supported upon inclines otherwise formed on or
carried by the block.

page_text: I, CHARLES CLAMOND, of 15 Rue Picot, Paris, in the Republic of 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 micro-telephonic instruments, as at present constructed, are of a bulky nature,
almost always necessitating the use of an induction coil; those which do not possess
this are wanting in energy in the transmission of speech, and their clumsy form prevent
their use in dwellings.
My present invention has for its object the construction of a micro-telephonic
instrument without induction coil, that shall be of small dimensions and shall transmit
speech with the same degree of distinctness as those instruments that have an induction
coil. It is necessary for this purpose in the first place that the diaphragm should be
in a vertical and not a horizontal position, as the latter arrangement necessitates a
considerable projection of the instrument from the face of the wall, which gives
it a clumsy appearance, as is the case with the Crossley, Ader, de Maiche, Gower-Bell
and other instruments, in which the microphonic contacts are suspended below the
horizontal plate that acts as diaphragm. On the other hand those instruments that
have been constructed with vertical diaphragms are rendered equally cumbersome on
account of the necessary devices for holding and regulating the position of the contacts
relatively to the vibrating plate.
The devices which I employ for the contacts according to my invention do not
require any regulation, so that I am enabled to construct such instruments of the
dimensions of about 34" in diameter by about 14" in depth. Generally speaking, any
micro-telephonic instrument must, in order to be able to transmit speech to considerable
distances with the same clearness and strength as the best telephones with bobbins,
have microphonic contacts complying with the following conditions: firstly, their
electrical resistance must be subject to considerable variations under the influence
of even feeble vibrations of the diaphragm; secondly, their electrical resistance,
when at rest, must always be practically equal, that is to say, it must sink back
to the initial value when the diaphragm ceases to vibrate; thirdly, they must
never separate from the diaphragm to such an extent as to cause a break of
contact even under the influence of the strongest vibrations. These conditions are
complied with by my construction of microtelephonic instrument, which I will proceed
to explain.
My invention will be readily understood on reference to Figs. 1 and 2 of the
accompanying drawings. A A is a vertical diaphragm of carbon or other conducting
material which is made to vibrate under the action of sound emitted near it, B is a

page_text: conducting block of carbon or other suitable material which is parallel to the
diaphragm A and contains a considerable number of cavities tt of cylindrical or
other form. In each cavity is placed a sphere which is generally made of carbon,
and which, bearing upon the edge m of the cavity, tends by its gravity to fall
over such edge (its centre of gravity lying always beyond such edge) and conse-
quently bears at the point n against the diaphragm A, which is thus put in
electrical communication with the block B. The pressure at the points of contact
due to a component of the weight of the spheres is invariably the same and conse-
sequently the resistance is always practically the same when the apparatus is in a state
of rest.
I am aware that there are a number of arrangements of microphonic contacts in
which either a ball or a cylinder is used, rolling or sliding upon an inclined plane such
as those of Bonta, Clay, Berliner, etc. and which are all arranged to be regulated with
initial pressure; but the characteristic feature of my invention is to group upon a
limited space a large number of spherical contacts each contained in a cavity and
each effecting a constant pressure upon the diaphragm and consequently requiring no
regulation. Thus while the considerable number of contacts employed prevents the
interruption of the microphonic circuit under the influence of strong vibrations, their
pressure, which is very slight, affords to the diaphragm all the required sensibility of
vibration.
Figs. 3 and 4 shew a vertical section and back view of a complete telephonic trans-
mitter constructed according to my above described invention.
The apparatus consists of a cylindrical metallic casing E E in the front part of which
is inserted the telephonic receiver T while the rear portion contains the transmitter
and the commutators. A disc D D of insulating material such as wood, ebonite etc.
carries at its middle the carbon block B with its microphonic spheres such as described
with reference to Figs. 1 and 2. In front of the disc D D and separated from the
casing EE by an insulating ring is situated the vibrating diaphragm A A against
which rest the spheres ss. At the back of the disc D D a spring blade N is fixed by
means of two screws which, at the same time, fix the blade P placed beneath N but an
insulating plate o separates the two blades, which are so mounted as to be thoroughly
insulated the one from the other. A bent commutator lever LL pivotted on a pin R
serves to cause the current to pass either through the bell signal when the telephonic
apparatus is at rest or through the apparatus. For this purpose the end of the
lever carries an incline 0. When the cylindrical telephonic receiver is introduced
into the casing EE, as shewn at Fig. 3, it raises the incline 0 thus causing the other
end of the lever L to bear upon the spring N which, in its turn, bears against the
blade and makes contact therewith, the blade P being in communication with
one of the terminals of the signalling bell, as shewn by the dotted connections.
At this time the whole of the current which passes through the line wire actuates
the signalling bell. If the telephonic receiver is then removed for the purpose of
communication, the spring N being relieved from pressure springs back so as to
make contact with the stop M, thus pushing back the lever L, the incline of
which passes through a slot in the casing and assumes the position shewn by the dotted
line 8
It will be seen as shewn by the diagram at Fig. 3 that the current then passes
through the microphonic apparatus and the telephonic receiver. A. button F at the
lower part of the apparatus fixed on the end of the spring P serves for calling.
In the position indicated in Fig. 3 it effects cominunication either with the signal
bell or with the telephone according to the position of the lever L, but if the
button F is pressed upon, the spring P touches the stop H, in which case the
circuit is closed for the signalling bell of the station with which it is desired to
correspond.
The telephonic receiver T contains a vibrating diaphragm, a bent electro-
magnet aba which polarises a soft iron core 4, which can be turned by a
screw driver so as to be adjusted in the receiving bobbin in order to regulate the
apparatus. The whole is fixed and secured by means of a wood disc K.

page_text: Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. In microphone transmitters, the arrangement within a small area of a considerable
number of balls contained in cavities in a fixed conducting block and so arranged as to
bear by the action of gravity against the vibrating diaphragm, so as to connect this
electrically with the said block.
2. In microphonic contacts such as are referred to in the preceding claim, arranging
the contact balls in their cavities in such manner that the centre of gravity thereof
always lies beyond the edge of the cavity, so that they are caused by the action of
gravity alone to bear against the diaphragm.
3. The herein described arrangement of bent commutating lever which is actuated
by the introduction into the casing and the removal therefrom of the telephonic
receiver.
4. The combined arrangement of micro telephonic apparatus constructed and
operating as herein described.