IMPROVEMENTS IN TELEPHONIC RECEIVERS "
Year: 1882

page_text: LETTERS PATENT to Theodore Torrey of Auriel Road, West Kensington in the
County of Middlesex for an Invention of "IMPROVEMENTS IN TELEPHONIC
RECEIVERS "
PROVISIONAL SPECIFICATION left by the said Theodore Torrey at the
Office of the Commissioners of Patents on the 30th November 1882.
THEODORE TORREY of Auriel Road West Kensington in the County of Middlesex
"IMPROVEMENTS IN TELEPHONIC RECEIVERS
"
My Invention relates to a telephonic receiver based upon the principle of
producing a variation of the magnetic attraction between the two poles of a
magnet (permanent or otherwise) by means of vibratory electric currents passing
through solenoids, bobbins, or coils placed between the two poles, the result being
a vibration of the mass of the magnetic poles themselves, corresponding to that
which originated in the transmitter at the sending station.
In carrying out my Invention with the use of a permanent magnet I take say
an ordinary horse shoe magnet (which may be supported in a suitable case in any
convenient manner) and I suspend between its two polar extremities, a solenoid
or bobbin the wires coiled around which may be led out through the bottom of
the case.
The metal core of the solenoid or bobbin is provided with a prolongation
at one end for attachment by means of a screw or otherwise to one polar extremity
of the magnet; the other end of the core is opposite the other polar extremity of
the magnet, to the outer side of which polar extremity is attached an ear piece of
vulcanite or other suitable material by which sonorous vibrations are conveyed
to the ear. The core of the solenoid or bobbin is so attached to the magnet as
to admit of movement or adjustment to or from the polar extremity last mentioned,
for which purpose its prolongation may be formed with an elongated hole through
which the attaching screw passes.
The Invention may also be carried out by the use of electro magnets in
substitution for permanent magnets.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Theodore Torrey in the Great Seal Patent Office on the
30th May 1883.
THEODORE TORREY of Auriel Road, West Kensington in the County of Middlesex
"IMPROVEMENTS IN TELEPHONIC RECEIVERS "
My said Invention relates to telephonic receivers of the class which operate by a
varying magnetic action produced by the passage of a current of electricity of
varying intensity which passes through a coil of insulated wire forming part of
the instrument Its object is to make a receiving instrument which shall be
of simple and solid-construction and therefore not likely to lose its adjustment and
which shall obviate the necessity for the thin disc of iron which has formed a
necessary part of nearly all previous instruments of this class This thin disc is so
easily injured by being bent or indented, and thus put out of its proper adjustment
relatively to the pole of the magnet which acts upon it that it has been necessary
to protect it from actual contact with external objects by means of a perforated
cap. This renders it impossible with such an instrument to bring the vibrating
plate so near the ear as might otherwise be done.
These difficulties are avoided according to the present Invention by so con-
structing the instrument that the whole mass of a magnet pole sufficiently rigid to
maintain its adjustment shall be thrown into vibration throughout its substance
this vibration being amplified and communicated to the ear by means of an
expanded ear piece of thin metal, vulcanite or other material possessing sufficient
strength and resonance attached to the vibrating pole in any convenient position
being as near as possible to the point where the varying magnetic action is
produced by the coil through which the current passes.
The Invention may be carried out by the use of either permanent magnets or
electro magnets
And in order that the said Invention may be perfectly understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several figures on the accompanying sheet of drawings, the same letters of
reference indicating corresponding parts in all the Figures.
Figures 1. 2 and 3 of the accompanying drawings are sectional elevations illus-
trating respectively three forms in which I have found it convenient to make my
telephonic receiver Figure 4 is a diagrammatic view illustrating the principle of
operation of the Invention
A is a horse shoe permanent magnet of a massive rigid character, between the
polar extremities a a' of which is suspended a coil of insulated wire B forming
part of the instrument and of the telephonic circuit, whilst to the polar extremity a
is attached an expanded ear piece Ĉ of thin metal, vulcanite or other material
possessing the requisite strength and sufficient resonance to convey sonorous
vibrations to the ear. The soft iron core b of the coil B is formed in the modifi-
cation Figure 2 with a prolongation b at one end for attachment by means of a
screw c or otherwise to the polar extremity a' of the magnet; the other end of the
core is opposite the polar extremity a of the magnet, to the end of which the ear
piece C is attached The dotted lines in Figure 2 show an alternative position of
the ear piece in which it may be placed with slightly better result than is obtained
from it in the position shown by the full lines, it being put in one position or the
other as preferred by the user as a matter of convenience in holding the instrument
to the car. The core of the coil is or may be so attached to the magnet as to admit
of adjustment to or from the polar extremity last mentioned for which purpose its

page_text: prolongation b' is formed, as indicated in Figure 2, with an elongated hole at o²
through which the attaching screw c passes. In the modification Figure 1 the
adjustment is provided for by screwing a portion 63 of the core separate from 6 to
the polar extremity a of the magnet and varying its position relatively to b by the
act of screwing or unscrewing the portion b to a greater or less extent, b being
attached to a' by a screw c. In the modification illustrated in Figure 3 the core
is also divided and attached to the opposite polar extremities of the magnet but
in this case accuracy in the construction of the instrument is alone depended upon
to secure the proper relative position of the parts
In the examples of my receiver shown in the drawings I have assumed that the
magnet itself forms the device for holding the instrument an enclosing case
being dispensed with. It is obvious however that a case may be used if found
desirable
Although in the several forms of my receiver illustrated in the drawings I have
shown a permanent magnet it is evident that in either case an electro magnet may
be substituted therefor
The principle of action of my Invention will be understood from an inspection
of the diagram Figure 4 in which 1 and 2 are the two limbs of a horse-shoe
magnet A The thick radial lines represent the particles of matter in the massive
rigid limb 1 converging towards the pole b around which is the coil B. Under
the variations induced in the core corresponding to the vibrations which
originated in the transmitter at the sending station, the particles in the limb 1 are
thrown into vibration as indicated by the curved lines, which vibrations are
distributed throughout the mass of the limb and extend to the ear piece C which
may be attached to it in either of the two positions shown as bereinbefore
explained, the result being that the articulate sounds uttered at the sen ling
station are faithfully and audibly reproduced at the ear of the listener placed
opposite the ear piece C.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is
A Telephonic receiver in which vibrations corresponding to those produced by
the emission of sound at a telephonic transmitter in circuit with the receiver, are
reproduced by the whole mass of a magnet pole being thrown into vibration
throughout its substance, such vibration being amplified and communicated to the
ear by means of an expanded ear piece attached to the vibrating pole, substantially
as herein before described
In witness whereof I the said Theodore Torrey have hereunto set my hand
and seal this thirtieth day of May in the year of our Lord One thousand
eight hundred and eighty three.
THODORE TORREY (L.S.)