Year: 1887

page_text: Date of Application, 6th Jan., 1887.
Complete Left, 22nd June, 1887.
Complete Accepted, 22nd July, 1887.
We THE STANHOPE COMPANY Limited of 20 Bucklersbury in the City of London
Engineers and GEORGE LEE ANDERS of 90 Worship Street in the City of London
Electrician do hereby declare the nature of our said Invention to be as follows:-
Our Invention relates to electric telephones operated by the vibration of an armature
in front of an electro magnet or electro magnets such electro magnet or electro magnets
being each wound and excited by coils of wire placed in the main circuit, or line. Our
invention consists in the method of connecting such coils with the exciting or line
battery in such a manner that the coils form what may be termed a balanced bridge
so that the magnets will be highly charged and sensitive while the balance will be
disturbed by current entering from a source outside the balance or by current generated
by vibration of an armature or armatures in front of one or more coils forming part
of such balance.
The manner of obtaining such balance is as follows:-The main line or wire is
joined to one end of each of two coils of equal or approximately equal resistance the
other end of one coil is then joined to the positive pole of the exciting battery and the
other end of the second coil is joined to the negative pole of the same battery; the
earth or return line is joined in a similar manner to two more coils whose resistances
are equal or approximately so, the other ends of such coils being joined to opposite
poles of the exciting battery in the same way as the first mentioned pair of coils. It
is not necessary that the four coils shall be all of equal resistance but the pair joined
to earth should be equal to each other and the pair joined to line should be equal to
cach other, or approximately so. It is evident that two or more coils in series or in
parallel may be used instead of any single coil provided that the resistance of such
substituted coils so arranged be equal to that of the corresponding balancing coil or
coils. It is also evident that one or more of the coils may be employed merely as
balancing resistances doing no electro magnetic work.
This method is applicable not only to instruments used as transmitters by means of
a current generated by the vibration of an armature in front of electro magnets, but
also where the bridging coils are part of a secondary induction circuit of which the
primary is influenced by a microphaic and a battery not in the main circuit.

page_text: When using the coils and battery as described and to effect the necessary connections
we employ an automatic switch such that while the receivers or one receiver shall be
hanging on hooks or a hook (or the equivalent thereof) one terminal of the battery
shall be connected directly to earth and the other terminal to the open point of a
calling switch or key connected to line or vice versa, and on taking the receiver off
the hook, the latter is moved by means of a spring and connects the coils with the
battery as above described.
The vibrating armatures may be of the ordinary kind forming part of a diaphragm
or diaphragms or they may be supported by or connected to the diaphragm or
diaphragms and pivotted in such a manner that one end is attracted to one magnet or
pole while the other end is repelled or released from another magnet or pole. Or
the armature may be fixed at one end to one magnet or pole, with its other
end opposite but not fixed to a second magnet or pole. Or again the armature may
be placed between two or more poles, so that it will be attracted by one pole or
set of poles and repelled or released by the other pole or poles.
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1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents for the said Stanhope Company
and George Lee Anders.

page_text: Improvements in and relating to Telephonic Apparatus.
We THE STANHOPE COMPANY Limited of 20 Bucklersbury in the City of London
Engineers and GEORGE LEE ANDERS of 90 Worship Street in the City of London,
Electrician, 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 :-
Our Invention relates to electric telephones operated by the vibration of an armature
or armatures in front of an electro magnet or electro magnets such electro magnets
being wound with and excited by coils of wire placed in the main circuit or line. Our
Invention consists in the method of connecting such coils with the exciting or line
battery, in such a manner that the coils form what may be termed a balanced bridge,
so that the electro magnets will be highly charged and sensitive, while the balance will
be disturbed by currents entering from a source outside the balance or by currents
generated by vibration of an armature or armatures in front of one or more coils
forming part of such balance.
The manner of obtaining such balance is as follows:-The main line or wire is
joined to one end of each of two coils of equal or approximately equal resistance,
the other end of one coil is then joined to the positive pole of the exciting battery and the
other end of the second coil is joined to the negative pole of the same battery, the
earth or return wire is joined in a similar manner to one end of each of two more
coils whose resistances are equal or approximately so the other ends of such coils being
joined to opposite poles of the exciting battery in the same way as the first mentioned
pair of coils.
Figure 1 of the accompanying drawings illustrates this arrangement-X being the
battery and L the line. A and B are equal coils, C and D are equal coils, and M is the
return or carth wire. It is not necessary that all the coils shall be of equal resistance
but the pair joined to earth should be equal to each other and the pair joined to line
should be equal to each other. It is evident that two or more coils in series or in
parellel may be used instead of any single coil provided that the resistance of such
substituted coils so arranged be equal to the resistance of the corresponding balancing
coil or coils. It is also evident that one or more of the coils may be used as or be
substituted by balancing resistances doing no electro-magnetic work.
This method of connection may be extended without departing from the principle
explained. For the sake of illustration we show one case in Figure 2 there being
three pairs of balancing coils and two batteries.
Our Invention is applicable not only to instruments used as transmitters by means
of currents generated by the vibration of armatures in front of electromagnets, but
also in cases where the balancing coils are part of a secondary induction circuit of
which the primary is influenced by a microphone and a battery not in the main circuit.
In such an arrangement the wire of the secondary circuit is the line wire so far as the
telephonic apparatus is concerned.

page_text: Figure 3 shews this arrangement, the primary circuit being indicated by thick lines
and the secondary circuit by thin lines.
When using the coils and battery as described and to effect the necessary connections
we employ an automatic switch such that while one or more receivors are hanging on
a hook or hooks (or the equivalent thereof) one terminal of the battery shall be
connected directly to earth or return wire and the other terminal to the open point of
a calling key or push connected to line (or vice versa) and on taking the receiver or
receivers off the hook or hooks the latter moves (or move) by means of a spring or
springs (or the equivalent thereof) and connects the coils with the battery as above
described.
The vibrating armatures used in connection with the magnets employed as described
may be of the ordinary kind forming part of or attached to a diaphragm or diaphragms,
or they may be supported by or connected to a diaphragm and pivotted in the centre
in such a manner that one end moves towards one magnet or pole while the other end
moves away from another magnet or pole. Or the armature supported by a diaphragm
may be fixed at one end to one magnet or pole, with its other end opposite but not
fixed to a second magnet or pole. Or the diaphragm armature may be placed between
two or more poles, so that it will be moved towards or attracted by one pole or set of
poles and moved from or repelled or released by the other pole or set of poles.
It will be seen that in all the above described arrangements the batteries are in the
line wires (or its equivalent) and there is no independent circuit insulated and separate
from the line wire as in many arrangements previously proposed in which electro-
magnets are used-In my Invention this is effected without its being necessary to
maintain a considerable current throughout the whole of the line wire thereby wasting
a great amount of electrical energy.
We do not confine ourselves to the exact modes of connection shewn in the diagrams
or to any specific number of electromagnets or coils, nor to any specific manner of
distributing such electromagnets or coils in transmitting or receiving instruments but
we claim :-
First In electric telephones the combination in the line wire (or its equivalent) of
coils (or a coil & electrical resistances) and a battery so as to form a balanced bridge
substantially as hereinbefore described.
Second In electric telephones the use of a battery in the line wire (or its
equivalent) so connected with coils (or a coil & electrical resistances) as to maintain
the magnetism of the requisite electro magnet or electro magnets without maintaining
any considerable current throughout the whole of the line wire (or its equivalent) and
forming therewith a balanced bridge substantially as described and for the purposes
set forth.
Third -The automatic switch for effecting the connections and disconnections of
the line wire or its equivalent with telephonic apparatus such as herein described
substantially as and for the purpose described.
Fourth In electric telephones an armature supported by or connected to a
diaphragm or diaphragms and pivotted in such a manner that its two ends are capable
of simultaneous movement in opposite directions substantially as described and for the
purpose set forth.
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