Improvements in Telephones.
Year: 1892

page_text: Date of Application, 2nd Mar., 1892
Complete Specification Left, 2nd Dec., 1892-Accepted, 4th Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements in Telephones.
We, JOSEPH BIRDUS SMITH BOOTH, of 14 Birch Street, Greenheys, and
ERNEST JAMES FALCONER, of 67 Higher Ardwick, both of Manchester in the
County of Lancaster, Electricians, do hereby declare the nature of this invention
to be as follows:-
This invention relates to electro-magnetic telephones of that type or class in
which the poles of a permanent or electro-magnet or magnets are arranged on
opposite sides of the diaphragm or diaphragms.
According to these improvements we arrange a coil upon each pole or pole
piece of the magnet or magnets, and join them up in the line circuit preferably in
parallel or derivation. Each of the coils is wound and joined in the same
direction. The coils may however in some cases be joined in series instead of in
derivation.
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Dated this 1st day of March A D 1892
..
WILLIAM E. HEYS,
Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Telephones.
We, JOSEPH BIRDUS SMITH BOOTH, of 14 Birch Street, Greenheys, and
ERNEST JAMES FALCONER, of 67 Higher Ardwick, both of Manchester, in the
County of Lancaster, Electricians, 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:-
This invention relates to electro magnetic telephones of that type or class in
which the poles of a permanent or clectro magnet are arranged on opposite sides of
the diaphragm or diaphragms, and its object is to increase the efficiency of such
telephones.
J
According to this invention we arrange a coil upon each pole or pole piece of
the magnet or magnets and join them up in the line circuit; preferably in
parallel or derivation. Each of the coils is wound and joined in the same
direction. The coils however may in some cases be joined in series instead of in
dérivation.
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"In all cases however the coils are so placed and connected that upon the passage
of a current they tend to form similar polarity upon the opposite sides of the
diaphragm, thus diminishing the magnetic force of the pole piece on one side of
the diaphragm and correspondingly strengthening that on the other. The diaphragm
is thus attracted' on one side and released on the other upon each variation of
current. In the event of an 'electro-magnet being used the energising coils and the
direction of current therein will remain constant.
In order that our invention may be 'more clearly understood, we have hereto
appended drawings to which we will refer.
Figure.1.illustrates a cross section of a telephone constructed according to this
invention with the ear or mouth piece placed over one of the pole pieces of the
magnet.
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Figure 2 is a similar section of a telephone with the ear or mouth piece arranged
at right angles to the position shewn in Figure 1.
Figures 3 and 4 are respectively plans of the instruments shewn in Figures 1 and 2.
"[Price 8d.]*
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page_text: Figure 5 illustrates, partly in elevation and partly in section, a view of the
instrument represented in Figure 2 at right angles therewith.
Figures 6 and 7 shew a form of the apparatus which may be used both as a
transmitter and as a receiver.
As indicated by the drawings the telephone magnet A which may be either
permanent or electrically energised is furnished with two inwardly projecting pole
pieces B B¹ each of these pole pieces carrying a coil of wire CC in connection
with the line circuit. These coils of wire are so wound disposed and connected
that upon the passage through them of an electric current they would tend to create
similar poles in each pole piece at the ends next to the diaphragm. By this means
of course the normal magnetism of one of the pole pieces would be increased and
that of the other diminished.
Many methods of winding and joining the coils to give this result are obvious but
a preferred method is to wind both coils in the same direction and connect them in
parallel the beginning of one coil and the end of the other being connected to one
line terminal. The same end may of course be easily attained by suitably connecting
them in series.
Between the pole pieces is placed the diaphragm D which is held in place by and
clamped between the two halves E E¹ of the body of the telephone. This
telephone body is preferably constructed of ebonite and may be secured to the
magnet by the screws F F¹. For the purpose of accurate adjustment the pole
pieces may be capable of longitudinal movement by means of a screw.
The diaphragm is thus placed in an intense magnetic field and is attracted
equally by both poles until the passage of a current through the coils. The
diaphragm is then attracted by the increased magnetism of one pole and the move-
ment is augmented by the corresponding decrease in the magnetic strength of the
pole on the other side of the diaphragm.
The pole pieces are preferably not permanently secured to the limbs of the horse-
shoe magnet but are furnished with projections which engage with holes in the
magnet. The limbs of the magnet are sufficiently elastic to allow of their being
sprung into place over the pole pieces.
In the form shewn in Figure 1 the ear or mouth piece G is placed over one limb
of the magnet and is in communication with one only of the chambers H H₁ which
are respectively formed on each side of the diaphragm by suitable recesses formed
in the halves E E' of the telephone body. The communication may be effected by
carrying a passage or hole J through the magnet limb and pole piece.
Both of the chambers may if desired be in communication with the ear
piece it being preferred in this case to form the ear piece G on one side of the
telephone body as shewn in Figures 2, 4, and 5, suitable holes leading to each of
the chambers.
Figures 6 and 7 illustrate a form which may be employed when it is desired to
use the same instrument both as a transmitter and as a receiver. The instrument
is provided with a lateral ear piece as shewn in Figures 2, 4, and 5, which however
is in communication with one side only of the diaphragm. The chamber on the
other side of the diaphragm is in communication with a peculiar quadrant shaped
mouth piece or trumpet K the entrance of which comes about opposite to the
speaker's mouth when the ear piece is placed to the car.
The pole pieces and coils on each side of the diaphragm may if desired in large
instruments be multiplied and joined and connected in a manner similar to that
employed with the single pair of coils.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. An electric telephone constructed and arranged substantially as hereinbefore
described and as illustrated by the accompanying drawings.
2. In an electric telephone the combination of horse shoe mernet or magnets.

page_text: co-axial opposing pole pieces furnished with coils, and a diaphragm placed
between the opposing pole pieces; constructed and arranged substantially as
hereinbefore described and as illustrated by the accompanying drawings.
Dated this 1st day of December A.D. 1892.
WILLIAM E. HEYS,
Agent for the Applicants.