Improvements in or relating to Telephone Transmitters.
Year: 1895

page_text: Date of Application, 1st July, 1895
Complete Specification Left, 27th Mar., 1896-Accepted, 9th May, 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to Telephone Transmitters.
I, THEODORE BERDELL, of Summit, in the County of Union, State of New
Jersey, United States of America, Gentleman, do hereby declare the nature of this
invention to be as follows:-
This invention relates to telephones, particularly to such as are employed for
transmitting articulate speech, and has for its object the provision of a transmitter,
cheap and simple in construction and very sensitive to sound.
To attain the desired end, my invention consists essentially in locating a
diaphragm, or diaphragms, consisting of or containing magnetic material, located
at the side of the pole or poles of a magnet, at right angles thereto, substantially
in the line of the greatest magnetic force, said diaphragm or diaphragms being
loosely held in position by the inagnetic force alone.
The magnet employed may be of the horse-shoe type, or two separate magnets
may be used, or a single magnet, the results being practically the same.
A single diaphragm may be used, provided with any style or arrangement of
contact piece, for instance of carbon; or two diaphragms, each provided with
contact pieces may be used, said contact pieces being located upon the sides of the
diaphragms farthest away from each other, the line of greatest magnetic force may
then pass substantially midway between the two diaphragms.
Dated this 1st day of Jul 1895
HERBERT HADDAN & Co.,
Agents to Applicant.
GUMI DEIE DIEUITIVATION,
Improvements in or relating to Telephone Transmitters.
I, THEODORE BERDELL, of Summit, in the State of New Jersey, U.S.A.,
Gentleman, 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 :-
My invention relates particularly to telephones such as are employed for
transinitting articulate speech, and has for its object the provision of a telephone
simple in construction, and very sensitive to sound.
My invention consists essentially in locating the diaphragm or diaphragms in a
magnetic field in a position of stable magnetic equilibrium, or position of magnetic
equipoise, as contradistinguished from an unstable position, or positions of magnetic
bias. When mounted in accordance with my invention, the movement or vibrations
of the diaphragm or diaphragms in either direction away from the normal position,
are in such direction with reference to the lines of magnetic force as to restore the
same, by the maguetic force to the normal position.
My invention further consists in mounting a diaphragm or diaphragms, unsecured,
and free to vibrate at the edges, in a magnetic field in a position of stable
magnetic equilibrium. When such a diaphragm is so mounted in a magnetic field,
and properly guided, it is practically floated in the magnetic field.
D

page_text: In carrying out my invention, the diaphragm which is of magnetic material, as
well understood in the art, may be placed in the magnetic field of lines of force
joining two poles either of the same or separate maguets, in a plane being
practically coincident with or parallel to said lines or the field in which it is
placed may be produced by the single pole of a magnet. In either case, the
direction of vibration of the diaphragm would practically be transverse to the
lines of force, or in such direction as to tend to carry the diaphragm from a
stronger to a weaker field, whereby it would be restored or drawn back to the
normal position which is the position of magnetic equipoise.
1 do not, however, limit myself to the number, or special disposition of the
magnetic poles, or special direction of lines of force with reference to the diaphragm,
as any mounting of the diaphragm in a position of magnetic equipoise or
equilibrium in a magnetic field would be within my invention.
My invention also consists in certain other novel and useful combinations
or arrangements of parts, and peculiarities of construction and operation, all
of which will be hereinafter first fully described, and then pointed out in the
claims.
In the accompanying drawings, forming a part hereof,
Fig. 1 is a longitudinal, vertical sectional view of a telephone embodying my
invention, taken at line a-a of Fig. 2.
Fig. 2 is a vertical, cross-sectional view, at line - of Fig. 1 ; and Fig. 3 is a
like view at line y-y of the same figure.
Fig. 4 shows the diaphragm as located between the poles of two separate
magnets; and
Fig. 5 is opposite to the pole of a single magnet.
Fig. 6 is a longitudinal, vertical sectional view of my telephone showing two
diaphragms, forming what I term a magnetic cushion."
66
Similar numerals of reference indicate corresponding parts in all the figures.
I will first describe the invention as carried out with a horse-shoe magnet, which
for illustration only is shown and described as a permanent magnet,
1 is such magnet. Between the poles of the inagnet is a box or case, 2, of any
approved insulating material, having an opening, 3, at its front for the admission
of sound. 10 is a diaphragm of soft iron, preferably free at its edges, and
guided in said case in any suitable way. The diaphragm, as illustrated in
Figs. 1, 2 and 3, is located in the magnetic field between the two poles of the
magnet, and its plane is practically coincident with the direction of the lines of
force joining eaid poles. The proper position may be readily determined by
allowing the diaphragm to move in the space between the poles in a direction at
right angles to the line joining said poles until it finds its position of rest or
equilibrium, which will be just back of the ends of the poles, and in the strongest
position of the field between them. If removed from this position in either
direction in a line transverse to a line joining the poles, the magnetic forces
would restore it to the normal position.
I have found that a diaphragm so mounted is very sensitive to sound waves,
particularly to such as are produced by articulate speech.
A diaphragm so mounted and arranged in a magnetic field is practically floated
in a magnetic field, being kept out of contact with the magnet, and being so floated
without any mechanical clamping or holding devices at its edge, is particularly
free to respond to sound vibrations.
When the diaphragm operates upon electrodes, the latter are preferably
mounted and supported as follows:-Placed across the case 2, are pencils or
cylinders, 4, usually of carbon, forming one of the electrodes of the telephone.
These pencils may be yieldingly supported at their ends by being held in a thimble
of rubber, or equivalent yielding material, 5. The pencils 4 are electrically
connected at 6, and are also electrically connected to a binding post 7, fixed in the
The binding post 8 is electrically connected with the diaphragm, or the
electrode thereon. Attached to the face of the diaphragm is a carbon electrode
case 2.

page_text: or electrodes, 11, which bears against the pencils 4. By the peculiar arrange-
ment of yielding supports for the ends of the electrodes 4, all buzzing or
snapping sounds are eliminated, while ample provision is made for the requisite
vibration.
The parts of my telephone may be mounted and enclosed in any convenient case,
when in use.
I have particularly illustrated my invention as employing a magnet of the
horse-shoe type, but two separate magnets may be used, or a single magnet, the
results being practically the same. In Fig. 4 the diaphragm 10, is shown
supported upon a non-magnetic piece, 12, between the poles 1, of separate
magnets, and in Fig. 5, but a single magnet, placed above the diaphragm, is
used.
In Fig. 6 is shown a second diaphragm 13, located and arranged precisely as
hereinbefore described. This arrangement forins a "magnetic cushion," and as
the two diaphragms constitute like magnetic poles, they will at all times maintain
the requisite normal position.
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. In a telephone, a diaphragm mounted in a magnetic field in a position of
magnetic equipoise or stable equilibrium.
2. In a telephone, a diaphragm free at its edges and floating in a magnetic
field.
3. In a telephone, the combination, substantially as described, with the diaphragm
free at its edges, of a guided case therefor, and a magnet or maguets in the field of
which the diaphragm floats.
4. In a telephone instrument, the combination with a horse-shoe magnet, of
a diaphragm floated in a position of magnetic equipoise in the field between the
poles of said magnet, and an electrode or electrodes upon which the diaphragm
operates.
5. In a telephone instrument, the combination with an insulating support, of an
electrode yieldingly mounted therein a magnet, and a diaphragm loosely resting
upon said electrode and mounted in a position of magnetic equilibrium between the
poles of said magnet.
6. In a telephone instrument, a suitable support, a magnet, and an electrode
formed of cylinders of carbon mounted at their ends in yielding rings within the
support, in combination with a diaphragm resting upon said cylinders and loosely
held in place with its plane parallel to the lines of force joining the poles of said
magnet.
7. In a telephone instrument, a support, a magnet, and a pair of carbon
cylinders yieldingly mounted within the support and forming an electrode, in
combination with a diaphragm loosely held in place in or about the position.
of magnetic equipoise in the field of force of said magnet, and bearing an
electrode.
8. In a telephone instrument, the combination with a magnet, of two independent
diaphragms, loosely held in place and adjustment by magnetic force, but out of
contact with the magnet.
9. In a telephone instrument, the combination with a magnet of two independent
diaphragms constitute like poles, located as set forth, thereby forming a magnetic
cushion.
hiq 97th dar
th day of March 1900.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, W.C., Agents for Applicant.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, W.C., Agents for Applicant.