1MPROVEMENTS 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 1MPROVEMENTS IN TELEPHONIC APPARATUS". to be as follows:-
ZE
This Invention, which relates to improvements in telephonic apparatus, consists
in instruments which may either be employed for transmitting or receiving
purposes.
In carrying out these improvements, a vibratile coil is pivoted within the stem
or cylindrical portion of the instrument, in such relation to a inagnetic field that
when used as a transmitter, the coil on being deflected has currents of electricity
induced therein and when used as a receiver, currents passing round the coil tend
to deflect the said 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 by this be suspended upon
a book when out of use. A permanent magnet may also be constituted of two bar
magnets arranged with their axes parallel and united at one end, these magnets
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
whose upper extremity a small hammer is attached in such manner as to be able to
vibrate upon one or other of two tympani arranged at either side thereof. These
tympani may be formed of gold-beater's skin, glass, mica, thin metal or other
equivalent material. At the lower part of the vibratile coil there is an elastic cord
for maintaining the coil in a neutral or normal 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 cuil. This clastic 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 be seen, upon the deflection of the coil consequent upon the vibration of
either of the tympani of the instrument when used as the transmitter, that
currents of electricity are induced within the coil and of positive and negative
Price B11

page_text: sense according as the said coil is deflected in one direction or the other. These
currents are conveyed along the line to the instrument being used as the receiver
and cause the hammers of that instrument to vibrate in like manner to those of
the transmitter.
more
It is to be understood that one or more or equivalent arrangement of permanent
magnets may be used for procuring an intense magnetic field for the coil to vibrate
in, and it is further to bo understood that the coil may be made to "stress
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 hammers upon one or
more pairs of such tympani,

page_text: J, 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.
In carrying my present Invention into practice I pivot the vibratile coil
a, within
the stem or cylindrical portion 6, of the instrument, in such relation to a magnetic
field that when used as a transmitter, the coil a, on being deflected has currents of.
electricity induced therein and when used as a receiver, currents passing round the
coil a, tend to deflect the said coil from its normal position. The permanent
magnet employed in this instrument is preferably of the ordinary horse-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 by this bo suspended upon a
hook when out of use. A permanent magnet may also be constituted of two bar
magnets arranged with their axes parallel and united at one end, these magnets
may if required be wholly enclosed within the instrument. A piece of soft iron c,
may be provided between the poles of the magnets 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 whose upper extremity a small hammer g, is attached in such manner
as to be able to vibrate upon one or other of two tympani h, arranged at either sido
thereof. These tympani h, are formed of gold-beators skin, glass, mica, thin metal
or other equivalent material and are carried in the frames, or their equivalents
secured to the body of the instrument. At the lower part of the vibratile coil a,
there is an elastic cord for maintaining the coil in a neutral or normal condition.
This elastic cord as shewn upon the annexed drawings may 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. The spirals j, 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 h, by which the instrument is placed in
circuit.
It will be seen, that upon the deflection of the coil a, consequent upon the
vibration of either of the tympani h, of the instrument when used as the trans-
mitter, that currents of electricity are induced within the coil and of positive
and negative sense according as the said coil a, is deflected in one direction on
;
•

page_text: the other. Those currents so induced within the coil a, are conveyed along the
line to the instrument being used as the receiver and cause the hammers h, of that
instrument to vibrato 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 procuring an intense magnetic field for the coil a, to
vibrate in, and it is further to be understood that the coil may be made 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 vibration of the hammers g, upon one or more pairs of such tympani h. Or in
lieu of the ear piece l, or in addition thereto, ear or mouth picces 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 car-piece l, and when used as a
transmitter the instrument is spoken into through the said ear-piece.
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, aro con-
ducted by means of a hammer 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 hereinbefore set forth with reference to the
annexed drawings.
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 ono 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 tho
tympani h, by the hammer g, all substantially as and for the purposes hereinbofore
set forth with reference to the annexed drawings.