IMPROVEMENTS IN TELEPHONIC INSTRUMENTS
Year: 1882

page_text: LETTERS PATENT to José Dottin Husbands, of Queen Victoria Street, in
the City of London, Gentleman for an Invention of IMPROVEMENTS IN
TELEPHONIC INSTRUMENTS
"
"
PROVISIONAL SPECIFICATION left by the said José Dottin Husbands at the
Office of the Commissioners of Patents on the 31st August 1882.
JOSÉ DOTTIN HUSBANDS, of Queen Victoria Street, in the City of London,
Gentleman, "IMPROVEMENTS IN TELEPHONIC INSTRUMENTS
"
My Invention relates to further improvements in telephonic instruments of that
class whereof I have described various examples in the Provisional Specification
filed with my application for Letters Patent the 24th June A.D. 1882, No. 3008.
The peculiar novel feature of these instruments as described in the said
Specification, is the employment of a disc or diaphragm consisting of two halves or
parts which form the terminals of the conducting wires, the said two halves or
parts being separated from each other by suitable insulating material and the
circuit being completed through the medium of carbon in the form of finely or
coarsely powdered coke, or in blocks, strips, or pieces enclosed with the said divided
disc or diaphragm, in a recess or chamber.
My present improvements consist in various details of construction which I will
now proceed to describe.
In one form of my transmitter I construct the two terminals or electrodes as
follows, that is to say, I take strips or pieces of thin copper or other suitable metal
and arrange them into a semi-circular or segmental shape to fit the circumferential
surface of a recess or chamber in which they are to be secured. On these electrodes
I form or fix tongues or strips so arranged that those of one electrode project and
lie between those of the other electrode, but without touching the same; or the top
or bottom of the recess or chamber, and the space between them, is filled, or partly
filled, with the granulated or powdered carbon or other suitable substance used for
regulating the electric current. These strips or pieces increase the metal surface in
contact with the carbon or other regulator and diminish the resistance at this part
of the circuit. The two electrodes are secured to a ring or case of vulcanite or

page_text: other suitable insulating material which forms, or is enclosed in, the said chamber or
recess, and the disc forms one side of the same. Instead of arranging the said
tongues or strips to project between each other they may extend radially inward
to near the centre of the recess or chamber.
In the above described form of my improved instrument the tongues, strips, or
pieces of metal are arranged vertically to the disc or diaphragm, but I modify this
arrangement by placing them parallel to the same with spaces between them and
the top and bottom of the recess to contain the material used for regulating the
current.
I still further modify my Invention by forming the two electrodes of the halves
of a short tube or cylinder united to form a complete tube or cylinder but insulated
from each other at their edges by strips of vulcanite or other suitable insulating
material and filled, or partially filled, with carbon in the form of powder or
otherwise. Or I sometimes unite the two parts at their edges by strips of carbon
grooved lengthwise to receive the said edges or otherwise properly secured thereto.
In some instances I place strips or sheets of wire gauze or thin metal or foil within
the said tube or cylinder and place the coke or other material thereon.
The ends of the said tube or cylinder are provided with covers to close the same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said José Dottin Husbands in the Great Seal Patent Office on the
28th February 1883.
José DOTTIN HUSBANDS, of Queen Victoria Street, in the City of London,
Gentleman, IMPROVEMENTS IN TELEPHONIC INSTRUMENTS
"
3J
My invention relates to further improvements in telephonic transmitters of a
class whereof I have described various examples in the Specification of my former
Letters Patent dated the 24th June, A.D. 1832, Nº 3008.
The peculiar novel feature of these instruments, as described in the said former
specification, is the employment of a metal disc or diaphragm divided into two
halves or parts which form the terminals of the conducting wires, the said halves
or parts being separated from each other and the circuit being completed through
the medium of carbon or other material which forms numerous points of contact
with the metal conductors, and which is affected by, and in unison with, the action
of the air-waves upon the diaphragm, the carbon being used in the form of finely
or coarsely powdered coke, or in blocks, strips or pieces between the parts of the
divided disc, and enclosed with the said disc or diaphragm in a recess or chamber
in the instrument.
But by my present invention I am enabled to construct the instruments either
with divided discs or diaphragms, as described in the said former Specification, or
with ordinary non-metallic diaphragms, or without a disc or diaphragm, the
vibrations of the voice being imparted through the case of the instrument to the
carbon or other regulating material within the same.
One important novel feature of this invention is the employment, in combination
with the carbon or other regulating material, of metal strips, tongues or pieces, in
such a manner that, when the vibrations of the voice are imparted to the regulating
material, it will be thereby caused to rub against the surfaces of the said strips or
pieces, and produce corresponding variations or fluctuations in the resistance to the
passage of the current.
In some cases, I employ the said strips or pieces in com-
bination with a divided disc or diaphragm. By employing these strips or pieces, I
increase the area of the metal surface in contact with the regulating material and
thereby diminish the resistance between the two terminals or electrodes. In some
instances, the parts of the disc or diaphragm form the terminals or electrodes, and
the said strips, tongues, or pieces are attached to them. In some instances, when
the parts of the disc form the electrodes, the said strips are not attached to them,
but are placed with the coke or carbon in the chamber or recess containing the
diaphragm, and in other instances the said tongues form the electrodes, or part of
the same.
My present improvements consist in various modifications and details of con-
struction of the instruments as illustrated in the accompanying drawings, which
I will now proceed to describe.
Figure 1 is a plan of an instrument in which a non-metallic disc or diaphragm
is arranged in combination with metal tongues or strips, some of which form one
electrode and the remainder form the other electrode.
Figure 2 is a transverse section on the line x, x, Figure 1.
The remaining figures are hereinafter described. a, a are the two parts of
the divided disc or diaphragm and a represents a non-metallic disc or diaphragm.
In the instrument shewn in Figures 1 and 2, the two terminals or electrodes
consist of the pieces b, c, formed partly of strips b', c¹, of thin copper or other
suitable metal, arranged in a semi-circular or segmental shape to fit the circum-
ferential surface of the ring d, of vulcanite or other insulating material, to which

page_text: they are secured. On these semi-circular strips I form or fix the tongues or strips
62, c², so arranged that the tongues b² of one electrode project and lie between the
tongues c of the other electrode, but without touching the same or the top or
bottom of the recess or chamber. The space between these strips or tongues is
filled, or partly filled, with granulated or powdered carbon or other suitable
substance used as the medium for varying the resistance and thereby giving to
the electric current the required undulating or fluctuating character. The ring d,
with the two electrodes secured thereto, is enclosed in a chamber or recess in the
case e of the instrument. The regulating material rests upon the disc or
diaphragm a¹ and a cover e¹ is placed over the said chamber or recess. It will
be obvious that no current can pass from the strips be to the strips c² except
through the carbon or other substance interposed between them. The air-waves
entering by the mouth-piece e cause vibrations of the diaphragm a', which
vibrations are imparted to the regulating material causing the same to rub
against the surfaces of the strips 62. c², and thereby produce variations or
fluctuations in the resistance to the passage of the current through the instrument.
I sometimes dispense with the diaphragm a' and enclose the strips or pieces,
and the regulating material, within a suitable case made of glass, wood, cork,
vulcanite or other non-metallic substance capable of transmitting the vibrations
of the voice, in such a manner that sounds produced in proximity to the said case
will cause vibrations to be imparted through the same to the regulating material
within, and thereby produce variations in the resistance to the passage of the
current in the manner above specified. It is not necessary that the electrodes
should be caused to vibrate. They may, if desired, be held immovably while the
vibrations are imparted to the regulating material.
In Figure 3 I have shewn the electrodes or terminals consisting of tongues
or strips b², c², secured to the rims or flanges b', c', but projecting radially therefrom
to near the centre of the diaphragm (or case) which is of suitable non-metallic
substance.
In Figures 2 and 2b, I have shewn, in plan and transverse section, an instrument
wherein each part a of the divided disc or diaphragm has tongues or strips
attached to it and projecting over, but not touching, the other part, that is to say,
the tongues 62 on the one part a project between the strips c² on the other part a
and vice versa, but the strips or tongues on each electrode forin practically part
of the same, and therefore are not in contact with each other. It is obvious that
this manner of attaching a strip may be adopted when the diaphragm is divided
into two circular parts, one surrounded by the other, the object being, in either
case, to combine the strips with the flat parts of the electrodes in such a manner
as to avoid giving unnecessary rigidity to the said electrodes. These strips or
pieces increase the area of the surface in contact with the carbon or other medium
and diminish the total resistance at this part of the circuit, thereby augmenting
the delicacy or sensitiveness of the instrument
Figure 4 illustrates another modification of the part of my invention whereby
the metal strips or pieces b², c² are arranged, in combination with the two parts a, a,
of the disc or diaphragm, within the space containing the carbon or other regulating
material. The said strips are fixed to a ring d of vulcanite or other suitable
non-conducting material, and, together with the parts a, a, of the diaphragm, form
the electrodes or terminals of the conducting wires which are connected to the said
strips, and to the parts of the diaphragmn as shown. The current, in its passage
from one electrode to the other, passes through the carbon, and the said strips or
pieces increase the area of the surface in contact with the carbon and reduce the
total resistance to the passage of the current through the instrument.
In the instruments shewn in Figures, 5, 6, 7, 10 and 11, the strips or pieces 6³
are employed in combination with a divided disc or diaphragm a, a, but do not
form parts of the terminals or electrodes, being used simply to diminish the
resistance to the passage of the current through the instrument.
Figure 5 shews, in plan, an instrument which has its diaphragm divided into two

page_text: circular parts to form the electrodes a, a; it also has metal tongues or strips bs
arranged between the carbon or similar material; the said strips are not connected
with the diaphragm but are attached to a ring d of non-conducting material
surrounding the said diaphragm.
Figures 6 and 7 are plans showing instruments provided with one metal strip b³,
of a zig-zag or undulating form, which is attached to a ring d of non-conducting
material and is not connected with either electrode or part of the divided
diaphragm.
In Figure 10, the strips 6s are circular or ring-shaped and are soldered, or
otherwise fixed, to the cross-bars or wires g, and these cross-bars are attached
to a ring d, of non-conducting material, which surrounds the two electrodes or
parts a, a, of the divided disc. In this case the rings b³ do not form parts of the
terminals or electrodes.
Figure 11 shews the metal strips bs attached to the ring d of non-conducting
material and crossing or intersecting each other. In this case, as in the instrument
shewn in Figure 10, the strips 63 are unconnected with the diaphragm or electrodes
a, a, but are placed, with the carbon or like material, in the chamber of the
instrument.
Figures 8 and 9 shew, in plan and transverse section, an instrument with a
modified arrangement of strips b, c, which form the electrodes or terminals, and
are used in combination with a suitable non-metallic diaphragm a'. The said
strips are secured to a ring d of non-conducting material.
Figure 9 shews the instrument provided with these devices in duplicate, the
mouth-piece e being arranged between the two diaphragms, so that the air-waves
will impinge upon both of them, and greater variations in the resistance to the
passage of the current will be produced by the vibrations of the voice than if only
one such device were employed.
Figure 12 is a plan and Figure 13 a transverse section illustrating a modifica-
tion of my instrument, in which I use, in combination with the split or divided
disc a, a, an annular metal plate 6' instead of a strip or series of strips; this plate
is supported at its edges by the pieces 6 as shewn, and it may be either formed in
one piece or divided into parts or sections.
Figure 14 is a plan and Figure 14° a transverse section of another form or modifi-
cation of my instrument, in which the strips or pieces 62, c² are inserted in slots
formed in a disc a' of mica or other non-conducting material. The strips 62 are
connected by a wire or rod b' and the strips c3 by a wire or rod c', and the said
strips and rods form the terminals or electrodes. In this form of instrument, I
employ either rods 2, of carbon, laid upon the said strips as shewn, or powdered or
granulated carbon placed between the strips.
In the instrument shown in plan in Figure 14b and in transverse section in
Figure 14, the strips b², c² are secured to a ring d of non-conducting material fixed
to a disc a¹ of mica or other non-metallic substance. This ring may be fixed to the
upper or lower face of the disc so as to form a chamber, within which is placed the
regulating material, the said chamber being closed at * by oiled silk, paper or
the like. The strips 62, c² are connected in a similar manner to those in Figures 14
and 14ª, and form the electrodes. The disc carrying the said ring and strips may
be fitted within any suitable case.
In the above described forms of my improved instrument, the tongues, strips, or
pieces of metal are arranged vertically to the disc or diaphragm, but I modify this
arrangement by forming and arranging the tongues 62, c² as shewn in Figure 15,
and placing them parallel to the diaphragm with spaces between them and the top
and bottom of the recess to contain the material used as the medium for varying
the resistance and producing fluctuations of the current.
I still further modify my invention as shewn in Figures 16 to 19. Figures 16
and 17 shew longitudinal and transverse sections of an instrument wherein I form
the two electrodes by taking a short tube or cylinder and dividing the same longi-
tudinally into two halves or parts a* as shown in Figure 17; these two halves are

page_text: BO placed together as to form a complete tube or cylinder, but are insulated from
each other by strips h of vulcanite or other suitable insulating material grooved
lengthwise to receive the said edges; the tube thus formed is filled, or partially
filled, as shown at i, with powdered or granulated coke or carbon, or other regulating
material, to complete the circuit between the two electrodes or half-tubes a*, a*, I
sometimes substitute for the insulating strips h, strips of carbon grooved to receive
the said edges, or otherwise properly secured thereto, in which case I may, or may
not, use the powdered or granulated material. In Figures 18 and 19 the parts or
electrodes a², a², are formed of strips or sheets of wire gauze (or thin metal or foil)
and are arranged within a tube or cylinder d' of vulcanite or other suitable insu-
lating material. The coke or other material is placed on the said electrodes as
shown at i. The ends of the said tubes or cylinders are provided with covers le
to close the same, as shown in Figure 16, and the tube may be placed in a box or
case of any convenient form. Either side or part of the tube will serve as the
surface to be spoken against in using the instrument.
In Figures 20, 21 and 22, I have shewn, in plan or face view, instruments in
which I have embodied further modifications of my invention. In the instruments
shown in Figures 20 and 21, there is a disc g of wood, cork, felt, asbestos, glass,
porcelain or other suitable material, upon which I mount and secure strips or
pieces a³, a³ of thin metal or foil to form the electrodes; and I form, in the said
disc or base, holes or sockets i¹ for the reception of balls or spheres of carbon, or I
fill the said recesses with granulated carbon or other material suitable for use as
the medium for varying the resistance in the telephone.
In Figure 20, it will be seen that the electrodes a³ are straight pieces in contact
with the carbon but separated from each other by a slight space through which the
circuit is completed or closed by the said carbon or regulating material.
In Figure 21, the arrangement is substantially the same as in Figure 20, but the
form of the electrodes a³ is varied to permit a triangular arrangement of the recesses
containing the carbon and thereby reduce the size of the instrument while retaining
the same number and size of such recesses.
In Figure 22, the electrodes a³ are ring-shaped or annular and the recesses con-
taining the carbon are arranged in a circular series within a ring d² of wood, cork
or other suitable material, which is attached to a disc a¹ of mica or other non-
conducting material, as shown, in transverse section, in Figure 23. The said disc is
fixed to the case in any suitable manner either at the point 2, or at 2', and the
vibrations of the voice impinging upon the centre of the disc will act with a certain
amount of leverage upon the regulating material.
The recesses containing the carbon, each form, in combination with the disc and the
electrodes, a transmitter, so that the instrument constructed in this manner forms a
kind of multiple transmitter.
I sometimes substitute for the electrodes a³ (Figure 22) a ring of non-conducting
material having two annular electrodes attached thereto and projecting into an
annular recess.
Having thus fully described my said invention and shewn how the same may
be conveniently and advantageously carried into practice I wish it understood
that although, as above stated, my present improvements are designed to further
develop and carry into practice some of the principles whereon the invention set
forth in the Specification of my said former Letters Patent No 3008 is based, yet
these improvements are distinct and separate from any of the features claimed in
the said former specification, that is to say, I do not make any claim to a divided
disc or diaphragm otherwise than in combination with the additional metal strips,
tongues or pieces which in some instances, as above stated, are attached to the parts
of the said divided disc or diaphragm and in other instances are detached therefrom,
but I Claim:-
First. In a telephonic transmitter, in which the circuit is completed through the
medium of carbon or other material suitable for varying the resistance in the
manner specified, the combination, with the said carbon or other material, of metal

page_text: tongues, strips or pieces arranged between, or alternately with, the same, for the
purpose of diminishing the resistance, and this I claim whether the halves or parts
of the divided disc or diaphragin form the electrodes or terminals with the strips,
tongues or pieces either attached to or detached from the same, or whether the said
tongues strips or pieces, in either of the various forms or arrangements herein
described, form the electrodes or terminals with, or without, the separate disc or
diaphragm.
Second. The modification of my invention wherein I arrange the terminals or
electrodes either in the form of, or within, a tube, the circuit between them being
completed by means of carbon or other suitable material, substantially as set forth.
Third. The modifications of my invention wherein I use balls or spheres of
carbon, or granulated carbon or other suitable material fitted in holes or sockets in
a disc or case or equivalent support and arranged in combination with metal strips,
rings or pieces forming the electrodes, in such a manner as to complete the circuit
between these electrodes, substantially as set forth.
In Witness whereof I the said José Dottin Husbands have hereunto set my
hand and seal this Twenty seventh day of February in the year of our
Lord One thousand eight hundred and eighty three.
JOSE DOTTIN HUSBANDS (L.S.)