Year: 1885

page_text: I CHARLES ADOLPH GISBORNE of 96 Newgate Street in the City of London,
Commission Agent do hereby declare the nature of this invention (a communication
to me from abroad by Frederic Newton Gisborne of the City of Ottawa, in the
County of Carleton, Province of Ontario, Canada, Engineer and Electrician, and
David Herbert Keeley, of the same place, Telegraphist) to be as follows:-
In receivers constructed according to this invention two or more magnets are
arranged upon the opposite sides of a vibratory diaphragm, preferably of iron, in
such manner that greatly increased vibrations of the diaphragm are obtainable by
alternate currents of electricity flowing through small helices of wire encircling the
respective and similar poles of the magnets.
În transmitters constructed according to this invention gravity multiple micro-
phonic contacts are so arranged that their movements are equal and simultaneous
when agitated or compressed by the vibrations of the diaphragm against which
they rest or with which they are connected. .
The object of the invention is to secure loudness and clearness of telephonic
articulation, with simplicity of construction, and without the necessity for variable
adjustments in the apparatus.
According to one form of the receiver, a diaphragm of iron rests against the
underside of an annular ring of iron or steel, to the upper side of which four
permanently magnetized arms are fixed with their positive poles converging
towards the centre; from the ends of these magnets an adjustable soft iron pole
piece projects towards the diaphragm through, and forming the core of, a bobbin
or helix of fine wire which is included in the main line circuit as hereafter
described.
The arrangement of the magnets, the pieces and coils, is the same on both sides
of the diaphragın. The effect of this disposition of the magnets is to polarize the
entire system in such a way that the diaphragm is of negative or south polarity
while the pole pieces between which it lies are of positive or north polarity, and
the diaphragm is indifferently attracted to either side. In operation the coils are
ID 071

page_text: so connected in the circuit that transmitted currents traverse them in opposite
directions, the result being an increase and decrease of the attractive power exerted
by the magnets through the pole pieces upon the respective sides of the diaphragm;
by this means the diaphragm is held normally without tension and when actuated by
reversed currents is given greater amplitude of vibration than can be imparted
under any other conditions.
The principle of construction of the receiver having been clearly explained, it is
obvious that the magnets may be of any shape adaptable to modified forms of the
instrument; and either one or both of the pole pieces may be of tubular form if
desired, and an expanding tube or horn may be attached to convey sounds emitted
by the diaphragm when vibrated.
When constructed as specially described it is found advantageous to cover
the openings in the containing box with a disc of wire gauze, or of wood or other
suitable material abundantly perforated.
The microphonic contact system or transmitter is as follows :-)
-In the centre of a
diaphragm of any suitable material is fixed a button of hard polished carbon and
just behind this is supported a block of carbon bored with say five borings inclining
downwards towards the diaphragm or the button which is affixed thereto; within
each of these borings there is placed two or three balls of carbon, one of soft rubber
and any required number of balls of lead or iron, necessary to ensure a sufficiently
firm gravity contact between the carbon balls and the button on the diaphragm.
This device constitutes the variable resistance to be included in the primary
circuit of an induction coil operating the telephone circuit. The conducting wires
are connected with the carbon button, and the block respectively, and the carbon
balls establish the connection between these terminals.

page_text: I, CHARLES ADOLPH GISBORNE of 96 Newgate Street in the City of London
Commission Agent do hereby declare the nature of this Invention (a Communication
to me from abroad by Frederic Newton Gisborne of the City of Ottawa in the
County of Carleton Province of Ontario Canada, Engineer and Electrician and
David Herbert Keeley of the same place Telegraphist) 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 the Invention is to secure loudness and clearness of Telephonic
articulation with simplicity of construction, and without the necessity for variable
adjustments in the apparatus.
In instruments constructed according to this Invention two or more magnets are
arranged upon the opposite sides of a vibratory diaphragm preferably of iron in
such manner that greatly increased vibrations of the diaphragm are obtainable by
alternate currents of electricity flowing through small helices of wire encircling the
poles of the magnets.
Figure 1 is a face view of one form of the instrument a diaphragm D of iron or
other material according to requirements as hereinafter explained rests against the
underside of a ring S of iron or steel to the upper side of which for permanently
magnetized arms M are fixed with their north poles converging towards the centre;
from the ends N of these magnets an adjustable soft iron pole piece or screwed
rod C projects towards the diaphragm through and forming the core of a bobbin
or helix E of fine wire which is included in a main line circuit in the ordinary way.
Figure 2 is a sectional side view of the instrument, On one side of the
diaphragm D, the magnets M, ring S, pole piece or screwed rod C, and coil E, are
arranged as represented in Figure 1; and on the other side an exactly similar
arrangement of parts but of opposite polarity; the magnets M³ having their south
poles in the centre and their north poles fixed to the outer ring. The diaphragm D
may be of iron insulated in its support between the ring S. N which are thereby
magnetically divided, or it may be of any nonmagnetic material with a button or
short cylinder A of soft iron fixed in the centre. The pole pieces CC are set so
as to exert an equal degree of attraction for the diaphragm; and the latter in
consequence rests indifferently attracted, to either side, and is free to vibrate in
response, when used as a receiver, to the variations of magnetism due to transmitted
currents traversing the wire coils E-E' which are included in the operating circuit
and act to simultaneously increase and decrease the magnetic attraction of the
poles C C³ respectively and alternately according to the direction of the transmitted
currents and when used as a transmitter the diaphragm vibrates in response to
sounds directed against it, and in its vibrations generates simultaneously (by its
approach to and withdrawal from the respective poles C C¹) two pulsations of
current in the coils E E' which combine in the operating circuit and affect the
distant receiver as one current pulsation of extra strength.
Figure 3 is a sectional side view of a modified arrangement of the parts designed
especially for transmission though it is obviously an excellent receiver.
In this

page_text: construction the magnets M M¹ upon both sides of the diaphragm D which is
of iron, are of like polarity; the pole pieces C C¹ being of north polarity and the
rings of south polarity. The diaphragmn D is in actual or magnetic contact with
the rings S and is in this instance provided at its centre with a short rod or button
of soft iron A which is in two sections screwed together through a small hole and
projects on either side. These projections enter the coils E E¹ the pole pieces C, C¹³,
being sufficiently withdrawn to admit them. As the magnets M M¹ impart north
polarity to the pole pieces C C¹ on either side of the diaphragm and south polarity
to the rings S S¹ which support the iron diaphragm the latter with its central rod
is likewise of south polarity, and the rod is indifferently attracted to either side by
the north poles C C so that the diaphragm is left free to vibrate and when spoken
against (the instrument being used as a transmitter) it will in its vibrations cause
the iron rod to recede from and approach the respective pole pieces C C¹ while at
the same time augmenting the electrical impulses thus induced in the coils E E¹
by its partial withdrawal from and further introduction into each of the coils
respectively thus transmitting a stronger pulsation of current to line than can
be generated when the diaphragm is used without the central projection A.
It is obvious however that the short rod or button A may be dispensed with, and
the poles C C¹ carried through the coils E. El to approximate the diaphragm D, as in
Figure 2, without seriously affecting the efficiency of the instrument, and this
arrangement is applicable in some instances as the instrument is then more
convenient for accurate adjustment.
In view of the foregoing explanations it will be readily understood that the
arrangement of the magnets M M² and of the pole pieces C C¹ and diaphragm D,
as represented in the respective figures 2 and 3, may be interchanged without
interfering with the scope and efficiency of the apparatus. And it is obvious that
the magnets M M¹ may be of any shape adapted to different forms of the instru-
ment so long as every facility, by open structure of the containing box is afforded
for the acess and egress of sounds directed against or emanating from the
diaphragm.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what
I claim as the invention communicated to me is:-
First. The arrangement of the magnets M M¹ of like or unlike polarity with
the central adjustable pole pieces C C¹ upon each side of the magnetic or non-
magnetic diaphragm D, substantially as described with reference to the accom-
panying drawings.
Second. The arrangement of the magnets M M of like or unlike polarity with
the central adjustable pole pieces CC upon each side of the magnetic or non-
magnetic diaphragm D, in combination with the short iron cylinder or button A
secured at the centre of and projecting from both surfaces of the diaphragm
substantially as described with reference to the accompanying drawings.