IMPROVEMENTS IN TELEPHONIC APPARATUS
Year: 1884

page_text: I, JOHNSTON STEPHEN, of Ravelston Cottage, Blackhall in the County of
Midlothian, North Britain, Journalist, do hereby declare the nature of the said
invention for "IMPROVEMENTS IN TELEPHONIC APPARATUS" to be as follows: —
This Invention, which relates to Improvements in Telephonic Apparatus,
consists in instruments which may either be employed for transmitting or
receiving purposes.
о
In carrying out these Improvements, a vibratile coil is pivoted within the stem
or cylindrical part of the instrument in such relation to a magnetic field that when
used as a transmitter the coil on being deflected will have currents of electricity
induced therein, and when used as a receiver, currents passing round the coil will
tend to deflect the coil from its normal position.-The permanent magnet employed
in this Instrument is preferably of the ordinary horse-shoe form, the bowed end of
which, may project to the outside of the instrument, and may, by this portion be
Buspended upon a hook when out of use. A Permanent Magnet other than of
horse-shoe form may be employed for the required purpose, such for example as
two magnets arranged with their axes parallel and united together at one end,
this magnet so constituted may, if required, be wholly enclosed within the
instrument. A piece of soft iron may be provided between the poles of the
magnet in order to concentrate the lines of force.-At the upper part of the
vibratile coil there is secured an arm at or near the upper extremity of which a
fibre is attached at or about its centre, while at its outer extremities it is secured
to two tympani of Gold-beater's skin, Glass, Mica, thin metal, or other equivalent
material. At the lower part of the vibratile coil there is provided an elastic cord
for maintaining the coil in a neutral. condition.-This elastic cord may be
constituted by the two terminals of the coil, these being so arranged spirally as to
admit of the required range of motion to the said coil-This cord is secured at its
extremities to the body of the instrument.-The terminals of the coil are led to
binding screws by which the instrument is placed in circuit.
It will thus be seen upon the deflection of the coil consequent upon the vibration
of either of the tympani when the instrument is used as a transmitter, currents of
electricity are induced within the coil and are of positive or negative sense
according as the said coil is deflected in one direction or another. The currents
4

page_text: are conveyed along the line to the instrument then acting as receiver and cause
the tympani of that instrument to vibrate in like manner to those of the
transmitter.
It is to be understood that one or more or equivalent arrangement of permanent
magnets may be used for providing an intense magnetic field for the coil to vibrate
in, and it is further to be understood that the coil may be caused to "stress" more
than one pair of tympani, and that a single ear-piece may be provided, upon the
Instrument, to collect and concentrate the vibration of the one or more pair of such
tympani. When the instrument is used as a receiver the motions imparted to the
coil stress the tympani of the receiving instrument.

page_text: Improvements in Telephonic Apparatus.
I, JOHNSTON STEPHEN of Ravelston, Cottage, Blackhall, in the County of
Midlothian, North Britain, Journalist do hereby declare the nature of my said
invention for IMPROVEMENTS IN TELEPHONIC APPARATUS 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 to improvements in Telephonic apparatus, or instruments
which may either be employed for transmitting or receiving purposes.
In order that my said Invention may be properly understood and readily
carried into effect, I will now proceed to describe the same with reference to the
drawings hereunto annexed.
Figure 1, is a vertical section of an instrument constructed according to and
constituting my present Invention.
Figure 2, is a vertical section of the same taken on a line at right angles to that
upon which Figure 1 is taken..
3
In carrying my present Invention into practice I pivot the vibratile coil a,
within the stem or cylindrical part b, of the instrument in such relation to a
magnetic field that when used as a transmitter, the coil a, on being, deflected, will
have currents of electricity induced therein, and when used as a receiver, currents
passing round the coil a, will tend to deflect the said coil from its normal position.
The permanent magnet employed in this Instrument is preferably of the ordinary
borse-shoe form, as represented at c, upon the annexed drawings the bowed end d,
of which, may as shewn, project to the outside of the instrument," and may, by
this portion, be suspended upon a hook when out of use. A permanent magnet
other than of horse-shoe form may be employed for the required purpose, such for
example as two magnets arranged with their axes parallel and united together at
one end, this magnet so constituted may, if required, be wholly enclosed within the
instrument. A piece of soft iron e, may be provided between the poles of the
magnet c, in order to concentrate the lines of force. At the upper part of the
vibratile coil'a, there is secured an arm f, at or near the upper extremity of which
a fibre g, is attached at or about its centre, while at its outer extremities the said
fibre g, is secured to two tympani h, of Gold-beaters skin, glass, mica, thin metal or
other equivalent material, the said tympani h, being carried in the frames i, or
their equivalents, secured to the body of the instrument. At the lower part of
the vibratile coil a; there is provided an elastic cord for maintaining the coil in a
neutral condition. This elastic cord may as shewn upon the annexed drawings be
constituted by the two terminals of the coil a, these being so arranged spirally as
at j, as to admit of the required range of motion to the said coil a. These spiralsj,
are secured at their outer extremities to the body of the instrument and from these,
the terminals of the coil a, are led to the binding screws k, by which the instrument
is placed in circuit.
It will thus be seen upon the deflection of the coil a, consequent upon the
vibration of either of the tympani h, when the instrument is used as a transmitter,
currents of electricity are induced within the coil and are of positive or negative

page_text: "
Bense according as the said coil a, is deflected in one direction or another. The
currents so induced within the coil a, are conveyed along the line to the instrument
then acting as receiver and cause the tympani h, of that instrument to vibrate in
like manner to those of the transmitter.
It is to be understood that one or more or equivalent arrangement of permanent
magnets may be used for providing an intense magnetic field for the coil a, to
vibrate in, and it is further to be understood that the coil may be caused to
"
stress more than one pair of tympani h, and that a single ear-piece l, as shewn
upon the annexed drawings, may be provided upon the instrument to collect and
concentrate the vibrations of the one or more pair of such tympani h. Or in lieu
of, or in addition to, the ear piece l, ear or mouth pieces may be provided at the
side of the case as shewn by dotted lines in Fig. 1-When the instrument is used
as a receiver the ear is placed against the ear-piece 7, and the motions imparted to
the coil a, stress the tympani h, of the said receiving instrument and when the
instrument is employed as a transmitter, it is spoken into through the said
ear-piece l.
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 is
First. The improvements in Telephonic apparatus consisting of an instrument
wherein, when used as a transmitter, the vibrations of the tympani h, are conducted
by means of a fibre g, to the coil a, in which coil by so vibrating in relation to a
magnetic field there are induced currents of electricity, of positive or negative sense
according as the coil is deflected in one direction or another all substantially as
and for the purposes herein before set forth with reference to the annexed
drawings.
T
Second-The Improvements in Telephonic apparatus consisting of an instrument
which, when used as a receiver, and having currents of positive electricity passed
therethrough has the vibratile coil a, deflected in one direction and when having
currents of negative, electricity passed, the vibratile coil a, is deflected in the
reverse direction, the vibrations thus imparted being communicated to the
tympani h, by the fibre g, all substantially as and for the purposes hereinbefore set
forth with reference to the annexed drawings.