IMPROVEMENTS IN ELECTROPHONIC.OR TELEPHONIC APPARATUS
Year: 1881

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
IMPROVEMENTS IN ELECTROPHONIC.OR TELEPHONIC APPARATUS."
1
A com-
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 4th May 1881.
"
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent
Agents, Southampton Buildings, London. IMPROVEMENTS IN ELECTROPHONIC OR
TELEPHONIC APPARATUS." [A communication from abroad by Louis Maiche, of
Paris, France.]
This Invention relates to improvements in electrophones or telephonic apparatus,
which according to the said Invention are provided with multiple vibrating plates,
and possess important advantages in comparison with all microphonic apparatus
hitherto in use.
It is well known that in apparatus of this class the currents sent through the
line are differential currents or induced currents determined by variations in
pressure between two contact pieces or between groups of pairs of contact pieces,
whereof one forms a part of a vibrating surface which are placed in the circuit of a
battery.
When these apparatus are used on lines which are of considerable length, and
consequently offer great resistance, or on submarine lines, recourse has to be had to
apparatus of great power, and they have to be provided with vibrating plates,
tongues, or surfaces of great dimensions. The use of these large vibrating surfaces
is attended by the great inconvenience of lowering the pitch or tone of the sounds
prouted in front of the apparatus, and consequently of rendering the same less
distinct, or they will in some cases transmit only such sounds as are sufficiently.
"high" Attempts have been made to increase the number of contact pieces
actuated by a vibrating surface of large size: the intensity of the sounds produced
has thus been augmented without however facilitating the transmission of "low"
[Price Gal.A

page_text: or deep sounds, which can only be obtained by means of vibrating plates of
comparatively speaking small size.
The present Invention is based upon the application to microphonic apparatus of
a separate vibrating plate or tongue for each contact-piece; I thus obtain at the
same time the advantages of an expensive vibrating surface with respect to the
intensely of the transmitted sóhuds, and also those of the smaller surfaces with
regard to the depth or pitch thereof. All the contact-pieces however act together,
and to this end they are connected, either for " quantity or for tension," and
they are traversed by the current from a battery placed either directly in the line
or in the coarse wire of an induction-coil, the fine wire of which is connected with
the line.
4
For directing and collecting the sound, a bell-shaped piece or speaking-trumpet
is placed before the vibrating plates.
It will readily be understood that the above indicated principle of my Invention
may be carried into practice in various ways. For instance, the necessary multi-
plicity of the vibrating surfaces may be obtained by means of entirely separate.
tongues or by producing knots or interruptions in certain parts of a single
tongue, that is to say, by rendering them immovable, say, by tightly pressing them
between two fixed plates provided with holes in such manner as to leave several
points free which can vibrate, in other words, in such a manner that they will
together constitute the requisite number of isolated vibrating tongues. In either
case a single bell-shaped piece or speaking tube may be used, or the bottom of the
same may be divided into as many tubes as there are vibrating tongues or centres
of vibration. Likewise, in both cases, the tongues or parts of one tongue which
vibrate may be plane, concave, or convex, and of any suitable shape.
The nature and form of the contact-pieces may also be varied within wide limits
without affecting the principle of my Invention.
I prefer to use as contact-pieces balls or spheres of carbon metallized or their
entire surface (excepting at the point at which contact takes place), so as to increase
their conducting power. This arrangement may moreover be applied to contact-
pieces of other than ball or spherical shape. The use of balls or spheres has the
advantage that adjusting devices are almost entirely unnecessary. These balls or
spheres may bear upon one another simply by their own weight or by the action of a
counter-weight, the position of which is regulated in any one apparatus once and
for all. I am also thus enabled to have very light contact-pieces, and so increase
the sensitiveness of the apparatus. Contact may also be produced between two
balls of carbon or between a ball of carbon and a pointed or other metallic surface,
say, of platinum, fixed on the vibrating tongue. In both cases I prefer to interpose
between the vibrating tongue and the contact-piece which is part of the same, a
small piece of cork, india-rubber, or analogous substance, which, softens the sound
of the voice.
On lines of considerable length it is desirable to increase the number of elements
in the battery, so as to overcome the resistance, but there is the risk of burning the
carbons or other bodies which form the contact-pieces. To avoid this danger,
which is considerable in my system, as the contact-pieces are light, I have adopted
a special arrangement of considerable importance, which I will now proceed to
describe.
The system of electrophonic transmission which I employ ordinarily belongs to
those in which an induction-coil is placed in the circuit of the battery, the currents
sent through the line being induced currents generated in the fine wire of the coil
by the variations of the intensity of the battery current; these variations are due
to the variations produced in the conducting power of the circuit under the
influence of the vibration of the contact-pieces with regard to the vibrating tongue.
I construct this induction-coil with two coarse or induction wires wound upon the
core in the ordinary manner, but in contrary directions. One (No. 1) is in per-
manent communication with the poles of the battery, whilst the vibrating contact
pieces are placed in the circuit of the other (No. 2). The length of these two wires

page_text: is so calculated that the total résistance of the two circuits is practically the same.
These two wires are connected before being united with the battery, it follows,
first, that if the contact pieces touch one another very lightly, the spark which is
liable to be produced at the interruption point will not be produced, as the portion
of the current which is unable to pass through the contact-pieces, that is to say,
How into the circuit No. 1, will simply flow through the circuit No. 2. Secondly,
the difference in the intensity of the currents passing through the circuits No. 1 and
No. 2, arises not only from the excess of current passing through the first, but also
from the diminution of the current passing through the second. The wires being
wound in contrary directions, the effects produced by the increase and the
diminution of intensity are the same in direction and join, and consequently the
intensity of the generated induced currents is doubled. It will however be clear
that the two inducing wires might be wound up in the same direction, and it
would suffice in this case to cross the attachments of these wires at the poles of the
battery.
It will moreover, be obvious that the same effects may be produced by means
of two separate coils having their induction-wires wound in contrary directions or
in the same direction, the two coils being interposed in the same circuit, and the
attachments to the battery poles being arranged according to the direction in which
the wires are wound, the fine or induction wires in this case being connected either
for quantity or for tension.
2

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
4th November 1881.
"
WILLIAM ROBERT TAKE, of the Firm of Haseltine, Lake, & Co., Patent
Agents, Southampton Buildings, London. IMPROVEMENTS IN ELECTROPHONIC OR
TELEPHONIC APPARATUS." A communication from abroad by Louis Maiche, of
Paris, France.
This Invention relates to improvements in electrophonic or telephonic apparatus,
which according to the said Invention are provided with multiple vibrating plate
or discs, and possesss important advantages in comparison with all microphonic
apparatus hitherto in use.
It is well known that in apparatus of this class the currents sent through the
line are differential currents, or induced currents determined by variations in
pressure between two contact-pieces, or between groups of pairs of contact-pieces
(whereof one forms a part of a vibrating surface), which are placed in the circuit of
a battery.
When these apparatuses are used on submarine lines or other lines which are of
considerable length, and which consequently offer great resistance, recourse must be
had to apparatus of great power, and provided with vibrating plates, discs, or
surfaces of large dimensions. The use of these large vibrating surfaces is attended
by the great inconvenience of lowering the pitch or tone" of the sounds produceil
in front of the apparatus, and consequently rendering the same less distinct; or
they will in some cases transmit only such sounds as are comparatively high."
Attempts have been made to increase the number of contact-pieces actuated by a
vibrating surface of large size. The intensity of the sounds produced has thus been
augmented, without however facilitating the transmission of low or deep sounds.
which can only be obtained by means of vibrating plates of comparatively small
size.
The present Invention is based upon the application to microphonic apparatus
of a separate vibrating plate or disc for each contact-piece. I thus obtain at the
same time an extensive vibrating surface, which is advantageous with respect to
transmission of the loud or intense sounds, and small surfaces, which areadvantageous
with regard to the deep or low tones or sounds. All the contact-pieces however
should act together, and to this end they are connected either for "quantity
for tension." and they are traversed by the currents from a battery placed either
directly in the line or in the thick wire of an induction-coil, whose fine wire is
connected with the line.
01'
For directing and collecting the sound, a bell or funnel-shaped piece or speaking
trumpet is placed in front of the vibrating plates.
It will readily be understood however that the above indicated principle of my
Invention may be carried into practice in various ways; for instance, the necessary
multiplicity of the vibrating surfaces may be obtained by means of entirely
separate or distinct dises or plates, or by employing a single plate, and rendering
certain parts of the same rigid or immovable by tightly pressing such paris
between two fixed plates provided with holes or apertures in such a manner as to
leave several points free to vibrate; in other words, in such a manner that such
parts will together constitute the requisite number of isolated vibrating portions of
the said plate. In either case a single bell-shaped piece or speaking trumpet or
mouth piece may be used, or a piece with the bottoni or inner end divided into as
many tubes as there are vibrating plates or centres of vibration. Moreover in
both cases the plates or discs or parts of a single plate or disc which vibrate may
present a plane, concave, or convex surface, and may be round, polyhedrical, or of
other suitable form,

page_text: The nature and form of the contact-pieces may also be considerably varied
without departing from the principle of my Invention.
I prefer to use as contact-pieces balls or spheres of carbon coated with metal
upon their entire surface (excepting at the point at which contact takes place), so
as to increase their conductibility. This arrangement may moreover be applied to.
contact-pieces of other than ball or spherical shape. The use of balls or spheres
has the advantage that with them adjusting devices are almost entirely unnecessary.
The balls or spheres may bear one upon another simply by their own weight, or by
the action of a counterweight, the position of which requires to be regulated only
once in any one apparatus. I am also thus enabled to have very light contact-
pieces, and so increase the sensitiveness of the apparatus. Contact may also be
established between two balls or spheres of carbon, or between a ball of carbon and
a pointed platinum or other metallic surface fixed upon the vibrating disc or plate.
In either case I prefer to interpose between the vibrating plate and the contact
piece which vibrates with the same a small piece of cork, india-rubber, or analogous
material, which softens the sound of the voice.
On lines of considerable length it is desirable to increase the number of elements
in the battery so as to overcome the resistance, but there is then the risk of
burning the carbons or other bodies which constitute the contact-pieces. To avoid
this danger, which is important in my system, as the contact-pieces are very light,
I adopt a special arrangement which I will now proceed to describe.
The system of electrophonic transmission which I ordinarily employ belongs to
the category of those in which an induction coil is placed in the circuit of the..
battery, the currents sent through the line being induced currents generated in the
fine wire of the coil by variations in the intensity of the battery current; these
variations are due to the variations produced in the conducting power of the
circuit under the influence of the vibration of the contact-pieres with regard to the
vibrating plate or disc. I construct this induction-coil with two thick or induction
wires wound upon the core in the ordinary manner but in opposite directions; one
wire (No. 1) is always in communication with the poles of the battery, whilst the
vibrating contact-pieces are placed in the circuit of the other wire (No. 2); the
length of these two wires is so calculated that the total resistance of each of the
two circuits is practically the same. These two wires are united before being
connected with the battery, consequently in the first place, if the contact pieces
touch one another very lightly, the spark which might otherwise be emitted at the
point of interruption will not be produced, as the portion of the current which is
unable to pass through the contact-pieces, that is to say, to flow into the circuit
(No. 1) will simply flow through the circuit No. 2; secondly, the difference in
the intensity of the currents passing through the circuits No. 1 and No. 2 arises
not only from the excess of current passing through the first, but also from the
diminution of the current passing through the second circuit; the wires being
wound in contrary directions the effects produced by the increase and the
diminution of intensity have the same result, and consequently the intensity of the
generated induced currents is doubled. It will, however, be readily understood
that the two induction wires might be wound in the same direction, and it
would suffice in this case to cross the points of attachment of these wires to the
poles of the battery.
It will, moreover, be obvious that the same effects may be produced by means of
two separate coils having their induction-wires wound in contrary directions or in
the same direction, the two coils being interposed in the same circuit and the
attachments to the battery-poles being arranged according to the direction in which
the wires are wound, the fine or induced wires in this case being connected either
for quantity or for tension.
In the accompanying Drawing I have illustrated one form of apparatus
constructed according to my invention. In this Drawing.
Figure 1 represents the interior of the box or case containing my improved
mechanism with the front or door wide open, and

page_text: Figure 2 is a transverse section of the said box and mechanism with the door or
front closed.
Figure 3 is a diagram illustrating the general arrangement of the wires and the
circulation or course of the currents in the apparatus."
Figure represents a pin or stud for pivotting or hinging to a bracket
hereinafter described the supports for the carbons which constitute the vibrating
contact-pieces.
Figure 5 represents a modified arrangement of the contact-pieces.
Figures 6 and 7 are vertical sections representing modifications in the arrange-
ment of the vibrating discs or plates and in the mouth-piece in front of which the
sounds are produced.
Figure 8 is a front view of my improved apparatus, and
Figure 9 is a rear view of the same.
Some of the above Figures are drawn to a larger scale than the others.
It will be seen by reference to the Drawing that the apparatus is enclosed
within a box or case a, whose front or door a*, which is hinged to the said box.
carries the speaking trumpet or funnel-shaped mouth-piece b. This door or front
has a series of apertures or openings in it. In the Drawing the said front is shewn
provided with four apertures. Behind each of these apertures is fixed a vibrating
disc or plate of metal or other suitable material. Each of these vibrating plates
carries upon its rear face a cork washer d, to which is attached by a wire a ball or
sphere of carbon that constitutes one of the contact-pieces.
The second contact piece consists of a ball or sphere of carbon, which is larger
in diameter than the ball e, and is coated with copper upon the whole of its surface
with the exception of that part or point of the same which is in contact with the
said ball e. The said ball is attached, to one arm of a bell-crank or elbow-lever g
which is hinged or pivotted in a bracket, the other arm of this lever is provided
with an adjustable counterweight. The hinging or pivotting of this lever is
effected by means of a specially-constructed pin represented on an enlarged scale
in Figure 4, and adapted to turn in the bracket with the lever g to the elbow of
which it is screwed. This pin is tapped and receives centrally at one end a set-
screw, thus allowing the conducting wire to be fixed at the centre of oscillation:
this conducting wire should be connected to the movable contact-piece in such a
manner as to offer the least possible resistance to the movements of the latter.
All of these pieces or parts are carried, by the front or door of the box or case.
the interior of this case I arrange the induction-coil (which may be constructed
as above described) and the terminals for the wires connected with the battery or
communicating with the line.
In
Moreover as in the apparatus at each station it is necessary to employ a
telephonic receiver and an alarm, the box or case is provided with a commutator
connectedwith or forming part of the exterior support for the telephonic receiver;and'
serving when the telephone is placed upon the said support or removed therefrom.
to put the line in communication with the vibrator of the coil which effects the
alarm or with the telephonic receiver.
Assuming that we are at station No. 1, and that the telephone is placed upon
its support and we desire to call station No. 2, it suffices to press or push inward
the button of the alarm so as to close the circuit, the current then takes the
following course, that is to say. it passes from the battery through the terminal #
and wire t, and thence to the levers and to the upper contact..piece
r of the
commutator. The telephone when resting upon its support presses the said levers of
the commutator against the contact-piece r, and the current passes into the wire
connected with the said contact-piece to the alarm. As the circuit closed the
current then passes through the wire p to the coarse or induction wire of the coil,
or to the coarse wires. if such are employed. It then passes through the
wire and terminal n to the battery. The wires o. p. extend to the two
terminals o p¹, upon the base of the coil to these terminals also extend interior
wires in communication with the vibrator of the coil, which is thus set in motion,

page_text: The circuit is then closed at all points, the current passes and induced currents are
set up in the fine wire of the coil which communicates with the earth and the line
by the wires r, c, and the terminals or posts a, y, and brings into the circuit the
two telephonic receivers, as will be readily understood by reference to the
Drawing.
The current thus thrown into the line enters the coil at station No. 2 and sets in
motion the telephone which produces the sound of the vibrator at station No. 1,
and thus calls the attention of station No. 2. The telephone is then removed from
its support, and the levers of the commutator is caused to swing by the action of
the spring into contact with the lower contact piece at of the commutator.
If a person then speaks in front of the electrophone at station No. 1; the current
from the battery arriving at the post or terminal # passes to the levers of the
commutator by the wire 7, then to the lower contact piece al of the said commutator,
and thence to the carbons or microphonic contact pieces through the wire 2, which
is subdivided and conducts the current by the wires 2, 3, and the connections
to two of the movable contact pieces f. Thence the current. passing through the
fixed contact pieces e upon the corresponding vibrating plates passes to two other
movable contact pieces by the wires ., and the connections, then traverses
the corresponding fixed contact pieces e and passes finally by the wires &. &, and
the wire to the post or terminal on the base of the coil. The current then
passes into the coarse wire of the said coil, determines the induced currents in the
fine wire by reason of the variations in resistance due to the variations of pressure
between the contact pieces, and returns to the battery through the wire o and the
post or terminal ».
The induced currenis set up in the fine wire of the coil pass into the line as
above described by the wire, the wire leading to earth.
If a current is sent from station No. 2 to call station No. 1. this current actuates
the vibrator of station No. 2, and passes to the post and the wire #, it then
enters the telephones prior to passing to earth through the wire and post or
terminal. The telephone at station No. 1 then gives out or causes to be heard
the alarm that has been sounded by the vibrator of station No. 2, and thus calls
station No. 1..
It will be readily understood that the connections may be so arranged so as
to directly actuate the vibrators at the stations called.
If a person then speaks at station No. 2, the induced currents sent into the line
arrive at the terminal y at station No. 1, and pass into the wire and into the
telephonie receivers which they actuate, and then pass to the earth by the
wire .
It will be seen that in the apparatus represented in the Drawing two of the
pairs of contact pieces united for quantity are connected for tension with two
others; it is however evident that this method of connection may be considerably
varied.
When two coarse or thick wires are employed in the coil they may be wound
The lengths of
side by side, or superimposed, or otherwise arranged in the same.
the two circuits designated above as Numbers 1 and 2 are such that their
resistances will be practically equal, as above stated, the difference will arise from
the interposition of the contact pieces in one of them.
In the modification illustrated in Figure 5. I employ instead of the carbon
contact piece fixed upon the vibrating plate a platinum contact piece e fixed
in the same manner as the said piece upon the said plate, that is to say, through
the medium of the washer d of cork or analogous material.
In the modification illustrated in Figure 6 I employ a single large vibrating
plate secured or held fast between two fixed pieces in such a manner as to leave
the said plate free only at a certain number of points which serve as vibrating
centres, or small and distinct vibrating dises or plates.
In the arrangement illustrated in Figure 7 the mouth-piece b is divided or

page_text: .
terminated by as many tubes * as there are vibrating plates in the apparatus,
these plates being isolated or formed of a single large plate, as above described.
Having thus fully described the said Invention, as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,-
First. The application to microphonic apparatus having differential multiple
contact pieces of a series of vibrating plates (one for each contact piece) so that the
said vibrating plates may be made of small dimensions and present a concave or
convex surface, and have a round or polyhedric form, the said contact pieces
working conjointly either for quantity or for tension, and being interposed either
directly in the circuit of a battery or in the circuit of the thick or induction wire,
of a coil whose fine or induced wire is connected with the line. all substantially as
above set forth and for the purposes specified.
Second. The formation of several vibrating parts by the use of a single plate of
suitable material and shape pressed or held between two fixed parts provided with
holes or apertures so as to afford different centres of vibration, as above set
forth.
Third. The combination of two or more microphonic instruments having single
or multiple contact pieces, so that they are all acted upon by one and the same
emission of sound, the whole forming the microphonic apparatus with multiple
vibrating plates, as above set forth.
Fourth. The month piece or speaking trumpet terminated by as many tubes as
there are distinct vibrating plates or centres of vibration, as above set forth.
Fifth. The special arrangement of the contact pieces, one of which is fixed upon
the vibrating plate directly or through the medium of a washer of cork or the like,
and consists of a ball of carbon or a metallic rod, and the other of which contact
pieces rests freely upon the first, and is adjustable upon a lever which carries an
adjustable counter weight, as and for the purposes set forth.
Sixth. Application of a metal coating to the surface of the contact pieces (when
they are formed of carbon or similar material) to augment their conductibility,
the surface at the points of contact being preferably left uncoated, as above set
forth.
Seventh. The induction coil (employed in combination with my improved
microphonic apparatus having multiple vibrating plates or multiple centres of
vibration) provided with two thick or induction wires wound in the same or in
opposite directions, and both connected to the battery or arranged for derivation
one upon the other. in the manner and for the purpose above set forth, and as
illustrated in the accompanying Drawing.
Eighth. The combination with my improved microphonic apparatus of two
separate ordinary coils with a single induction wire, so arranged as to act in the
same manner as the coil with two induction wires, the fine wires of the two coils
being connected for tension or quantity, as above set forth, to enable the same
results to be attained as those obtained by the arrangement. hereinbefore set.
forth.
Ninth. The apparatus comprising the various parts above described, combined
and arranged substantially in the manner and for the purpose above set forth; and
as shewn in the accompanying Drawing.
In witness whereof, T, the said William Robert Lake, have hereunto set my
hand and seal, this Fourth of November. in the year of our Lord One
thousand eight hundred and eighty one,
WM. ROBT, LAKE. (...)