Improvements in Telephonic Receivers.
Year: 1891

page_text: Date of Application, 22nd July, 1891
Complete Specification Left, 21st May, 1892-Accepted, 25th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Telephonic Receivers.
I, ALEXANDER MARR of 9 Repton Street Manchester in the County of
Lancaster, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
This invention relates to telephonic receivers and its object is to secure loudness
of speech and tone reproduction and greater susceptibility to faint currents.
In proceeding according to these improvements, I employ two double-pole
magnets and two diaphragms. The diaphragms are arranged in parallel planes
between the poles of the magnets and between them are arranged high resistance
coils included in the line circuit. The cores of these coils are built up of segments
each of which is insulated from its neighbours preferably by mica or ebonite and
they may be built upon a star-shaped centre of ebonite and be enclosed in an ebonite
or other suitable insulating tube.
The magnets are preferably arranged in planes parallel with the diaphragms and
their poles are in this case turned at right angles so as to be perpendicular to the
diaphragms, and the poles may or may not also be wound with wire coils included
in the line circuit. The distances between the diaphragms and the magnets may be
regulated either by moving the magnets or by adjusting their poles independently.
The opening in the casing through which the sounds produced by the vibrations
of the diaphragms are conveyed to the ear communicates with the space between
the diaphragms and these as well as the casing may be shaped so as to allow the
car to be brought as closely as possible to the source of sound.
The fineness of the wires in the coils and consequently also, the numbers of turns
will in each case be determined by the resistance of the circuit on which the
instrument is to be used and by other conditions, but I prefer to use comparatively
fine wires.
Dated this T..1. AD 1001
WILLIAM E. HEYS,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Telephonic Receivers.
I, ALEXANDER MARR of 9 Repton Street Manchester in the County of
Lancaster, Electrical Engineer, 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 telephonic receivers and its object is to secure loudness
of speech and tone reproduction, and greater susceptibility to faint currents.
In the construction of an instrument according to these improvements, I employ
two double-pole magnets and two diaphragms. The diaphragms are arranged in
parallel planes between the poles of the opposed magnets, and between the
diaphragms are arranged coils included in the line circuit. The cores of these
coils are built up of segments each of which is insulated from its neighbours by a
suitable insulating material, and preferably by mica or ebonite.
The two double-pole magnets may be of any convenient and suitable form,
preferably arranged parallel with the diaphragms, and have their poles or pole-
pieces turned at right angles or arranged so as to be perpendicular to the diaphragms,
Paine 871

page_text: and the pole-pieces may or may not also be wound with wire coils included in the
line circuit. The distances between the diaphragms and the magnet pole-piece
may be adjusted and regulated by movement of the magnets or of their pole-pieces
if desired.
I will more particularly describe my said invention with reference to the accom
panying drawings in which-
Figure 1 represents an end clevation, a part of the cap and diaphragm being
shewn broken away;
·
Figure 2 a longitudinal section ;
Figure 3 a horizontal section;
Figure 4 a front view of the instrument fitted with tubes, part of which are
represented as broken off;
Figure 5 a perspective view of the core used in the coils; and,
Figure 6 transverse sections of the constituents or elements of the core as
preferably constructed, arranged in their relative positions, but at a greater
distance apart than in the completed core.
In each of the figures where the parts are represented, A. A' are the magnets;
B, B', their pole-pieces; C, C¹ the coils on the magnet pole-pieces; D, D¹, the
two parallel diaphragms; E, E¹ the two coils between the diaphragms; F, F, the
coil cores; G, the casing of the instrument; H, H¹, the caps; I, the sound
orifice (Figure 2) which is applied to the car when the instrument is in use;
and J, J (Figure 4) car and mouth tubes which may be employed in substitution
for the sound orifice shewn in Figure 2.
The magnets which I prefer to use are of the modified horse-shoe type shewn by
the figures, with circular pole-pieces at right angles. They may be secured to
the caps of the instruments by the screws S, and their pole-pieces are of such a
length as to come into proximity with the diaphragms, as indicated.
The caps may be secured to the central casing by screws and the adjustment of
the distances between the pole-pieces and the diaphragms may be adjusted by
means of paper or other thin packing rings between the caps and the diaphragms
or casing. The peripheries of the diaphragms are held and secured between the
caps and the casing as in other receivers.
The coils on the magnet pole-pieces may or may not be employed, according to
the length of line with which the instrument is to be used; being included in the
case of long circuits, and omitted for short ones, if desired.
The cores of the two coils E E¹ are arranged in line with the respective opposed
pole-pieces of the magnets as shewn by Figure 3. The coils are firmly held in
place in an internal annular projection P of the casing G, and their cores have
such a length as to come into such close proximity with the inner faces of the
diaphragm as will allow their free vibration, as in the ordinary Bell receiver.
All the coils are included in the line circuit, and they may all be in series, or,
when the pole-piece coils are used, these may be in parallel circuit with the internal
coils. This arrangement, and the number of turns of wire in each coil may be
decided for average cases, but it is preferred to vary them, as is well understood,
for different circumstances and conditions of use.
The sound waves originated by the diaphragms may be conveyed to the ear from
the outsides, from the insides, or from both sides of the diaphragms. As illustrated
by Figure 2, the sound waves pass outwards from the outer sides of the diaphragms
through openings O formed in the bases of the caps. In this form, additional
openings may be made in the annular conical recess R, formed in the caps and
casing, which will permit the sound waves to pass from between the diaphragms
outwards. In use, this recessed part of the instrument is applied to the ear.
the modification represented by Figure 4, two tubes K K' are employed. These
communicate respectively through the caps with the outer sides of the diaphragms,
and one may be applied to each ear. As it is well understood that this type of
instrument may be employed both as a transmitter and as a receiver, these two
tubes may be very conveniently used for both purposes, one being applied to the
In

page_text: ear for the reception of messages, and the other to the mouth for their transmission.
The tubes may obviously be differently arranged; for example, one may com-
municate by a junction or breeches pipe with the two outer sides of the diaphragms
and the other directly with the space between the inner sides, or one tube may
communicate with the inner and outer side of one diaphragm, and the other with
the inner and outer side of the other diaphragm.
The connection of the line circuit with the coils may be made through suitable
terminals such as T T.
The cores for the internal coils, and also, if thought desirable, the pole-pieces
also, may be constructed as represented to an enlarged scale by Figures 5 and 6.
It is preferred to make the segments F¹ as small as convenient, but about eight
will generally be found to be a convenient number. These are arranged upon an
insulated centre, and are well insulated from each other. The segments may be
drawn to the desired section by the ordinary wire drawing processes.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is,
1. A telephonic receiver, constructed and arranged substantially as hereinbefore
described and illustrated by the accompanying drawings.
2. In a telephonic receiver, the combination and arrangement with two parallel
diaphragms, of two independent magnets each having two pole-pieces arranged in
opposition to the pole-pieces of the other magnet, and two internal coils arranged
with their cores in line with the opposed pole-pieces; substantially as hereinbefore
described and illustrated by the accompanying drawings.
3. In a telephonic receiver, the combination and arrangement with two parallel
diaphragms, of two independent magnets each having two pole-pieces in opposition
to the pole-pieces of the other magnet, a coil on each of the pole-pieces, and two
internal coils arranged with their cores in line with the opposed pole-pieces;
substantially as herein before described and illustrated by the accompanying
drawings.
4. In telephonic receivers, coil cores constructed of insulated segments, sub-
stantially as hereinbefore described and illustrated by Figures 5 and 6 of the
accompanying drawings.
Deted the 10113
D 1000
WILLIAM E. HEYS,
Agent for the Applicant.