Improvements in Audible Signalling Apparatus.
Year: 1893

page_text: Date of Application, 11th Apr., 1893-Accepted, 10th Feb., 1894
Improvements in Audible Signalling Apparatus.
I, WILLIAM HENRY FAHRNEY, residing at No. 112 S. Hoyne Avenue,
Chicago, in the County of Cook and State of Illinois, United States of America,
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 more particularly to means whereby instruments for
producing loud sounds may be utilized for sounding a telegraphic code, so that
messages may be sent at a distance without the intervention of wires or conductors;
but I wish it to be understood, nevertheless, that I do not limit the scope of my
invention to this particular use, for, as will hereinafter appear, the invention is also
applicable to systems or devices for the transmission or production of other forms
of audible signals.
The primary object of my invention is to render electrically produced signals
more audible than heretofore, whereby they may be understood at a greater
distance from the receiver or sounder; thus providing for communication between
distant vessels at sea, or between other distant points where it is impossible,
inconvenient or undesirable to string the usual conductor.
In a more limited sense, the object of my invention is to vary the capacity of a
resonance tube by the closure of a key or circuit closer.
With these ends in view, my invention consists in certain features of novelty
hereinafter described and claimed, and shown in the drawing.
In carrying my invention into effect, I employ means, for producing when desired,
a continuous and uniform sound, connected with a source of any suitable fluid under
pressure and having a resonator provided with a sensitive portion or medium, and an
electro magnet arranged to act upon said sensitive medium when a circuit closer or
key closes the circuit through the helix of such magnet. As an example of a device
for producing such uniform and continuous sound, I have a shown a steam or air
whistle which may be connected with any well known source (not shown) of fluid
under pressure.
In order that the fundamental principles of my invention may be more readily
comprehended, let it be supposed that an electro magnet is arranged with its pole
steam or other
or poles in near proximity to the side of the bell or cup portion of
whistle or horn composed of magnetic metal, as soft iron or steel, and that while
the whistle is sounding, such magnet is successively energized and de-energized: it
will be seen that at the instant the magnet becomes energized its magnetic influence
will be imparted to the whistle cup and if such influence be sufficiently powerful,
it will tend to arrest the vibrations of the cup or to set up a counter or contrary
vibration in that portion of it at least which is in the immediate vicinity of the
magnet, and in either event, the regularity or uniformity of the sound vibrations
of the cup will be destroyed; thus causing the tone of the whistle to vary in strict
accord with the existence, duration and strength of the magnetic influence.
It is found in practice, however, that for the more useful purposes to which my
invention may be employed, the whistle bell or cup alone is so rigid that it is not
sufficiently responsive to the weaker and rapidly recurring impulses of the magnet.
Hence, it is necessary for many purposes to render a portion of the bell or cup
more sensitive, without destroying the sonorous qualities necessary for the
production of loud sound.

page_text: in the accompanying drawings in which,
of
Fig. 1 is a diagrammatic view illustrating a simple embodiment of the principle
my invention.
Fig. 2 is an enlarged sectional view of the preferred form of apparatus, and
Fig. 3 is a plan view thereof.
Like signs of reference indicate like parts throughout the several views.
Referring to Figure 1 of the drawings, from which the foregoing principles may
best be understood, A indicates the device for producing a continuous or uniform
sound here shown as a whistle; B represents a circuit closer or telegraphic key, and
.C the electro magnet whose helix may be placed in circuit with any suitable
source D of electric energy, through said key.
If the invention is to be used for telegraphic purposes the magnet C and
armature heretofore described, acts as the electric telegraphic receiver or sounder,
the sound of the whistle A being effected by the electric vibrations.
The cup or bell portion a of the whistle is provided with a sensitive diaphragm E,
.which in this form is of course composed of magnetic metal and may be secured in
place in any suitable manner or in the manner ordinarily followed in the
construction of telephones. This diaphragm forms a part of the wall of the cup or
'bell a, and may be located at any convenient point, but it is preferably so situated
as to form the top or crown of the cup; and the pole or poles of the magnet are
arranged in near proximity to it, as for instance, in an ordinary Bell telephone
receiver.
It will now be seen that at the instant the key B is closed, the diaphragm E
will be attracted by the magnet, thus causing a single vibration of the diaphragm.
If at this instant the whistle should be sounding the vibrations imparted to the
diaphragm by the rushing steam or other fluid used and by the vibrations of the
balance of the whistle cup, will be wholly or partially checked, or the tension of
the diaphragm increased by the influence of the magnet, and as such vibrations of
the diaphragm were, at the time the key B was closed, making sound waves which
lent tone to the general tone of the whistle and which blended with the general
tone of the whistle, it stands to reason that the general tone of the whistle as
heard, would be varied by the influence of the magnet on the diaphragm. When
the key is again opened, breaking the circuit, the diaphragm springs back to its
former position, restoring the original or initial tone of the whistle. Thus, a
.complete vibration of the diaphragm while the whistle is sounding, will result in
a continuous blast, consisting of three divisions: the first and third being the
natural or initial tone of the whistle, and the second being a different tone whose
duration and pitch will depend respectively upon the length of time that the
circuit is closed and the strength of the magnetic influence.
While the instrument which I have now described is capable of carrying out
my method, it is found in practice, nevertheless, that owing to the necessity of
employing a comparatively weak electric current for energizing the magnet, it is
necessary that the magnet should be located with its core very close to the
diaphragm; but when this is done the movement of the diaphragm is insufficient to
produce results of practical utility, and the diaphragm moreover, is liable to strike
the magnet. Hence, I find it desirable and advantageous to impart the magnetic
impulse to the diaphragm through the intermediary of leverage and a separate
armature, whereby the slight movement of such armature will result in an
exaggerated movement of the diaphragm. An example of a convenient and
.effective form of lever connection is shown in Figures 2 and 3 of the drawing, and
which I will now describe more in detail.
In this form of the device it is of course not necessary that the diaphragm be
constructed of magnetic metal, as the magnet may be arranged to act upon an
intermediate armature. The diaphragm E' as before described, is mounted in any
convenient and well known manner at the upper end of the resonance tube or
chamber a composing the whistle cup, and suitably mounted above the diaphragm

page_text: are two electro-magnets C¹, preferably such as ordinarily employed in the sounder
or receiver of the telegraphic instrument, two magnets being employed for the sake
of greater strength.
These magnets may be mounted upon a plate F, which in turn, is supported upon
upright arms G provided with a threaded ring g, screwing into the upper end of
the whistle cup and serving to hold the diaphragm in place.
The plate F is provided on one side with a laterally projecting arm H in the
upturned end of which is pivoted an armature lever I, to which is secured the
armature J. On the other side of the plate F is a lateral arm K in which is
pivoted a lever I whose inner end is preferably arranged between the magnets, and
is pivotally connected to a depending stem or rod M, the lower extremity of which
latter is screw threaded, and passed through the diaphragm E', and adjustably
connected thereto by means of clamp nuts m, or by any other convenient device,
the stem M being secured to the diaphragm instead of resting upon it, for the sake
of avoiding displacement and preventing rattling.
The armature lever I has an extension projecting beyond the armature and
passing through an upright arm N which is adjustably clamped to the extension i
by a set screw n at its upper end, while at its lower end it is adjustably secured to
the lever L a convenient means for accomplishing such adjustable connection
consisting of a pin O in the end of the arm N, arranged to play in a longitudinal
slot formed in the lever L.
By this arrangement it will be seen that the extent of the movement of the
diaphragm resulting from the movement of the armature J, may be regulated by
shifting the arm N on the armature lever toward or from such armature accordingly,
as it is desired to decrease or increase the movement of the diaphragm.
The whistle cup or resonance cup a may be of any well known construction; [
have shown a form however, consisting of a funnel shaped chamber or cup, and I
prefer to employ such form as it is found that it produces a deeper and clearer
sound with a minimum amount and force of the steain or other fluid under pressure
employed.
The electro magnets C₁ are connected by suitable couductors to the battery D
and key or circuit closer B as before described.
It will now be seen that when the circuit at B is closed, the armature J will be
attracted by the magnets and such movement will be multiplied by the levers I
and L, and transmitted to the diaphragm which will consequently be depressed into
the whistle cup or resonance tube, thereby varying the capacity or interior dimensions
of such tube or cup.
Hence, if at this time the whistle should he sounding, its tone or pitch would be
altered the instant the diaphragm became depressed, and such altered tone would
exist until the circuit were again broken, whereupon, the whistle would resume its
normal or original tone or pitch. It will therefore be readily understood, that the
dot and the dash, or any other code of signals may be produced in the tone of the
whistle by the proper manipulation of the key B.
It will also be seen that the action of the diaphragm is equivalent to that of an
ordinary movable piston, as its purpose is to vary the capacity of the resonance
tube, and hence, it is to be understood that by the term, sensitive medium or
diaphragm, I include an ordinary pisten for which the diaphragm is often used as
a substitute in other arts. It is to be also noted however, that the diaphragm such
as I have shown and described, possesses advantages over the ordinary piston in this
particular connection, inasmuch as it is capable of lending sound vibrations to the
general tone of the whistle while it forms a tight joint and is not liable to rattle, and
does not require to be accurately ground and fitted to the interior of the cup, as
would be necessary with the piston.
Such a device as I have now described may be put to many useful purposes,
among which might be mentioned that of telegraphy, and more especially for the
purpose of telegraphing at sea; for it is evident that two vessels equipped with
such devices, might, while passing each other at sea, communicate through the

page_text: agency of their whistles or horns, according to any of the well known telegraphic
codes, or according to any other code of signals.
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. The combination with a source of fluid under pressure, of a horn or whistle
having a resonance tube or chamber connected therewith, and the wall or side of
said tube or chamber being provided with a continuous unbroken sensitive medium,
and means for vibrating said medium whereby the capacity of said tube or chamber
will be varied, substantially as set forth.
2. The combination of a horn or whistle, an electro magnet arranged to vibrate
a portion of the resonator of said horn or whistle, and means for energizing and
'de-energizing said magnet, substantially as set forth.
3. The combination with a source of fluid under pressure, of an instrument for
producing uniform audible sound, connected therewith, and having a sensitive
medium, an electro magnet arranged to control the vibrations of said medium, and
'means for temporarily energizing and de-energizing said magnet, substantially as
Bet forth.
4. The combination with a source of fluid under pressure, of an instrument for
producing uniform audible sound connected therewith, and having a sensitive
diaphragm forming a part of its resonance chamber, an electro magnet arranged to
control the vibrations of said diaphragm, and means for temporarily energizing and
de-energizing said magnet, substantially as set forth.
5. The combination with a source of fluid under pressure, of an instrument for
producing uniform audible sound connected therewith, and having a sensitive
medium, an electro magnet provided with an armature having lever connection with
said sensitive medium, and means for energizing and de-energizing said magnet,
'substantially as set forth.
6. The combination with a source of fluid under pressure, of an instrument for
producing uniform audible sound connected therewith and having a sensitive
diaphragm, a lever attached to said diaphragm, and an electro magnet having an
'armature connected with said lever, substantially as set forth.
7. The combination of a whistle having a sensitive diaphragm forming the upper
end thereof, and an electro magnet arranged to vibrate said diaphragm, substantially
as set forth.
8. The combination of an instrument for producing audible sound having a
sensitive medium, an electro magnet having an armature, a lever upon which said
armature is mounted, and a second lever connected to said first lever and to said
sensitive medium, substantially as set forth.
9. The combination of an instrument for producing audible sound having
sensitive medium, an electro magnet having an armature, a lever to which said
armature is secured, a second lever secured to said sensitive medium, and an
adjustable arm connecting said levers together, substantially as set forth.
10. The combination of a whistle having a funnel shaped resonance tube or cup
and a sensitive diaphragm forming the upper end of said cup, an electro magnet
for vibrating said diaphragm, and means for energizing and de-energizing said
magnet, substantially as set forth.
2 TIL
ليمى
1
of February A.D. 1893.
WILLIAM HENRY FAHRNEY.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.