Year: 1886

page_text: I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings in the County of Middlesex, 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 object of my invention is to so construct an induction coil for telephonic
purposes that the current from a local battery may be utilized to induce a line
current upon a secondary or sub-coil, and to amplify a local induced current in a
third sub-coil, whereby I am enabled to eliminate the usual objectionable effects
upon the receiving instrument of line induction, all of which is hereinafter
particularly described.
In the accompanying drawing,
Figure 1 is a side view of my improved coil, a portion of the same being in
section and broken away in order to show the different windings, and
Figure 2 is a central longitudinal sectional view, showing the manner of
constructing said coil, together with an outline or diagram of the connections of the
respective sub-coils with the telephone system.
Like letters of reference indicate like parts in the different Figures.
A Figure 1 represents an ordinary insulating spool surrounding the usual soft
iron core B... I first wind upon said spool a primary coil C of large insulated wire,
and then, suspending said winding, I place over said primary coil C, a primary
induction winding or coil D of fine insulated wire, the terminals d, d, Figure 2 of
which preferably connect respectively with the line D¹ and ground D'.
Around said primary induction winding I place a secondary induction coil E, of
like or varying resistance to that of said primary induction coil, but preferably the
same, the terminals e, e¹ of which may be connected with an ordinary magneto
receiver F, as shown in Figure 2, thus forming a local circuit therewith. Or
a receiving telephone provided with an electro magnet or its equivalent, may be
used in which event I place a local battery in circuit therewith as shown in the
drawings.

page_text: Around said coil E, I then continue the winding of said primary coil C, thus
forming a primary extension C³.
The convolutions of all of said coils are in the same direction, and the
terminals c, c¹ respectively of said primary and primary extension. coils are
connected with the binding posts g, g¹ of a transmitting instrument G, in circuit
with which a local battery H is interposed.
The influence of a passing current through the primary coil C, induces a current
upon the coil D and line D2, the return of which forms a local induced current
upon the coil E in circuit, as stated, with the receiver F, the action of which local
induced current is, in turn, amplified by the local battery current upon the
primary extension coil C¹.
By this system of coils, and by thus placing the receiver, I am enabled to
overcome certain difficulties and objections incident to the placing of said receiver
directly in circuit with the line wire. The disturbances which result from line
induction are largely avoided, while the sounds from the transmitting instrument
are thus rendered clearer and more distinct.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is
First An induction coil consisting of a primary coil of coarse wire surrounding
a soft iron core, a primary induction coil of fine wire, the terminals of which are
designed to be connected with the line and ground respectively; a secondary
induction coil of fine wire, with the terminals of which a local circuit may be
formed; and a primary extension coil of coarse wire surrounding the whole, the
terminals of said primary and primary extension coils being intended to be in
circuit with a local battery, substantially as, and for the purposes, set forth.
$
Second-In an induction coil having the core B, the primary coil C, the coil D,
the primary extension coil C¹ and the interposed coil E arranged substantially as,
and for the purposes, set forth.
Third-The combination in an induction coil, of a soft iron core, a primary coil
of low resistance, primary and secondary induction coils of high resistance, and
a primary extension coil surrounding the whole, substantially as, and for the
purposes, set forth.
.
Fourth-An induction coil consisting of a primary coil of coarse wire enveloping
a soft iron core, a primary induction coil of fine wire having its terminals
connected with a telephone line and with the ground respectively, a secondary
induction coil of fine wire and a primary extension coil, said primary and primary
extension coils being in circuit with a local battery, in combination with a
telephonic transmitter and receiver, the former of which is interposed in circuit
with said primary and primary extension coils, and the latter with said secondary
induced coil, substantially as, and for the purposes, described.
ليمي
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