IMPROVEMENTS IN TELEPHONES OR VOCAL SOUND TELEGRAPHS
Year: 1881

page_text: LETTERS PATENT to Robert Minturn Lockwood and William Van Orden
Lockwood, both of the City, County, and State of New York, in the United
States of America, for an Invention of "IMPROVEMENTS IN TELEPHONES OR
VOCAL SOUND TELEGRAPHS."
"
COMPLETE SPECIFICATION filed by the said Robert Minturn Lockwood and
William Van Orden Lockwood at the Office of the Commissioners of Patents
on the 31st May 1881.
ROBERT MINTURN LOCKWOOD and WILLIAM VAN ORDEN LOCKWOOD, both of
the City, County, and State of New York, United States of America, Electricians.
IMPROVEMENTS IN TELEPHONES OR VOCAL SOUND TELEGRAPHS."
Figure 1 is a vertical section through our improved transmitter and stand or
support, showing the arrangement of the microphone and of the spool or coil, and
by diagram the relation of the several wires thereto; Figure 2 is a perspective
view of the coil enlarged, and partly broken away to show the "half connection
of the second wire with the wire forming the coil; and Figure 3 is a detail view,
showing one way of forming said half connection.
"
Our Invention relates to a novel manner of forming or winding the coil, whereby
we get a second wire leading from the coil at a point at or near its centre, without
breaking the single wire of uniform size forming the coil. It further relates to a
novel construction of the base or support for the transmitter, said support being
made in hollow cylindrical or barrel form, and forming a sleeve or cylinder
surrounding the spool or helix; to a novel construction of hood or dome covering
the microphone, and to a novel arrangement of the spool or helix and microphone
relatively to each other, and to the cylindrical base or support, as hereinafter
explained.
In the accompanying Drawings A represents the base or stand, made in the
form of a hollow cylinder, preferably of uniform bore or internal diameter, except
near its upper end, where it is enlarged to receive the microphone, or cork B in
which the microphone is embedded, and which fits snugly in said upper end, as
shown.

page_text: The stand or base is by preference made of metal, but it may be made of other
suitable material, and lined with metal, forming a cylinder or sleeve within the
stand and surrounding the coil, for a purpose hereinafter explained.
In either case any desired ornamental configuration can be given to the outer
surface of the stand or base, as shown. Within the stand or support thus
constructed is arranged the helix coil C.
In the construction of our coil we take by preference a core or magnet D, and
wrap the same with wire wound thereon in the usual manner until the coil is about
one third (more or less) wound, the end of the wire beginning the coil projecting
at 1, and being connected with the battery, as hereinafter explained.
When the coil is thus about one third wound a second wire is attached thereto
by a half connection and carried out therefrom, as shown at 2, without breaking
the main wire, which is then further wound until the coil is completed, terminating
in the outer end or wire 3, or, in other words, starting with the wire 1, the coil is
wound about one third (more or less), when a second wire 2 is joined thereto by
a half connection (one form of making said connection being shown in Fig. 3), and
carried thence directly out at one end of the spool, and the winding of the first
wire is then resumed until the coil is complete, terminating in the wire or outer
end thereof at 3. Thus it will be seen there are three wires or ends extending
out from the coil, said ends passing by preference through perforations in the
lower end flange of the spool, and also through the table or shelf E, on which the
stand or support A is placed. By this arrangement we get three ends, 1, 2, and 3,
projecting from the coil.
The first named is shown as connecting the coil with the battery through post a;
the second wire 2 is connected directly with the lower plate or button of the
transmitter, and the third wire or end 3 of the main wire of the coil is connected
with the receiver R through the binding post d and the ground. Wires c, c', are
connected with the carbon plates or buttons, the one c¹ directly with the lower
disc or button, and the other c either directly to the upper disc For through a
connecting pin passing down therefrom. The wire c is carried down through
the stand or support A by the side of the coil, and is connected with a battery
binding post a¹, the other c¹ passing down in a similar manner, and being connected
directly with or forming an extension of the wire 2 of the coil. The battery posts
are indicated by the letters a, a¹, and the line binding posts by d, d, and these
posts extend through the shelf or bracket E, and through suitable insulators
therein, and have the wires connected to and through them, as will now be
explained. The battery is indicated in the diagram by the letter B, the ground
by G, and the receiver by R. The battery is connected by wires f. f³, with the
binding posts a, a, and the latter is connected by wires c¹ with the transmitter or
microphone, as above explained, and the binding post a is also connected with the
transmitter through the wire 1, the half connection wire 2, and the wire c¹, The
line binding posts are connected with the battery and the transmitter and receiver
as follows, viz. :-
The battery post a¹, which is connected with the transmitter by wire cas
explained, is also connected by a wire g with line post d, from which a wire h
extends to the receiver, and thence by wire to the ground. The post d¹ is
connected with wire 3 of the spool and with the ground. By this arrangement of
wires and construction of coil we obtain the following three circuits, viz. First, a
battery or transmitter circuit, indicated by arrow 1, viz., starting from post a through
wire 1 to the coil, out through wire 2 and wire c¹ to the transmitter, thence
through c to battery post a¹, through wires fand f and battery to post a, the
starting point, which circuit, it will be seen, is not grounded and is in continuous
action; second, the line battery circuit, indicated by arrows 2, starting at post a¹,
thence by wire g to line post d, through the receiver and ground to post d, thence
to and through wire 3 of the coil to wire 1, thence to battery post a, and through
the battery by wires f' and f to post a', the starting point; and, third, a talking or
telephone circuit, indicated by arrow 3, starting at post a³, thence by wire g

page_text: through line and line post & to the receiver, through ground circuit to line post d¹,
thence through wire 3 and coil to wire 2, through c¹ the transmitter and c to
post a¹, the starting point, cutting out the battery, over which latter circuit a
current is produced by the combination of the two battery circuits, one passing
through the transmitter and not through the line, and the other through the
transmitter and the line. The base or support A, being of metal or lined with
metal in the form of a sleeve or cylinder is connected with the ground by a wire,
as shown, or in other suitable manner, and surrounding the coil or spool as it does
acts as an escape for induction and greatly improves the action of the apparatus.
By this construction of coil we get what we term a "third or "telephone" current
differing from and independent of the battery and induction currents, but
depending on the battery current to produce it, and one which is found in practice
to be particularly adapted to telephonic purposes.
The coil may be constructed or wound in the usual way, except in the particulars
pointed out, and the connections and half connections described may be made in
the usual or any preferred form. We do not wish therefore to be confined to the
specific form and arrangement of the wires in connection with the battery and the
transmitter and receiving devices, so long as the feature of the second wire
introduced into the body of the coil is preserved, and a third or battery telephone
circuit is formed through the interposition of said wire as explained.
The microphone or transmitter is placed in the enlarged receptacle in the upper
end of the barrel or support, and consists of the carbon plates or buttons, two or
more F, F1, F2, one over or upon another as shown, the lower ones F1, F2, being
made each in the form of a flat ring, or of a disc having a central perforation i, as
shown in Fig. 1, and the upper one F similar in form, but with a pendent spur or
pin in lieu of the central perforation, said spur passing through the perforation i
in the lower button or buttons, and being insulated from the walls or sides thereof
by a ring of hard rubber or other suitable material.
The microphone is embedded in a block B of cork or other non resonant material,
having a suitable chamber B₁ formed in it for its reception, the buttons fitting
snugly within the chamber and being provided with a covering B³ of cork or other
material, similar to that of which the non-resonant block B is composed.
It may sometimes be found desirable to use two, three, or more sets or series
of these microphones or multiple buttons, each connected with a separate battery
but all covered by a single hood or dome; but under ordinary circumstances and
for short distances the single one composed of two or more buttons arranged one
upon the other, as described, has been found to answer all requirements. The upper
end of the stand has an annular rabbet A2 formed on its outer face or periphery,
and upon this rests a metal hood or dome A¹, which by preference from the plane
of the button F upward is made in the form of a hollow hemisphere or
approximating thereto, so that all sound waves or pulsations entering said dome
through the mouth piece A³ shall be directed thereby to a common centre, viz., the
microphone. The dome thus formed rests on the rabbet or shoulder A2, and may
be rotated freely thereon to bring the opening or mouth A³ therein into convenient
relation to the speaker.
Having fully described our Invention, what we desire to claim and secure by
Letters Patent is,-
1st. The magnetic coil or helix formed from a single main wire in combination
with a second wire introduced into the body of said coil and connected with
the main wire, substantially as and for the purpose described.
2nd. The combination of the magnet or core, the single main wire wound thereon
and forming the coil, and the second wire introduced into the body of the coil and
connected with the main wire, substantially as described.
3rd. The fixed metal cylinder or base supporting the microphone and enclosing
the coil, substantially as described.
4th. The dome or mouth piece to the transmitter made in the form of a

page_text: hollow hemisphere, or approximating thereto, forming a cover for the transmitter,
substantially as described.
5th. The dome or hemispherical cover or mouth piece to the transmitter, made
adjustable or susceptible of being rotated on its base or support, substantially as
described.
6th. The transmitter composed of two or more plates or buttons of carbon or
equivalent conducting material resting in contact and embedded in a non-resonant
material, one or more of said buttons being provided with a central perforation,
through which connection of the upper button is made with the circuit, substantially
as described.
7th. A transmitter composed of several sets or series of multiple buttons covered
by the single hood or dome, each of said sets or series being connected with a
separate battery, substantially as described.
8th. The fixed cylindrical metal stand supporting the microphone and enclosing
the coil, in combination with the hollow dome covering the transmitter, as
described.
9th. The fixed hollow metal stand or base supporting the microphone and
enclosing the coil, in combination with a wire or conductor connecting said fixed
base with the ground, substantially as and for the purpose described,
In witness whereof, we, the said Robert Minturn Lockwood and William
Van Orden Lockwood, have hereunto set our hands and seals, this Thirty
day of May, in the year of our Lord One thousand eight hundred
and eighty one.
ROBERT MINTURN LOCKWOOD.
(L.S.)
WILLIAM VAN ORDEN LOCKWOOD. (L.S.)