AN IMPROVED EAR TRUMPET
Year: 1876

page_text: LETTERS PATENT to John Stewart Wallace and Edward Tucker, both of
Belfast, in the County of Antrim, for the Invention of "AN IMPROVED EAR
TRUMPET."
PROVISIONAL SPECIFICATION left by the said John Stewart Wallace and
Edward Tucker at the Office of the Commissioners of Patents on the 13th April
1876.
JOHN STEWART WALLACE and EDWARD TUCKER, both of Belfast, in the County of
Antrim. AN IMPROVED EAR TRUMPET."
"
The usefulness of phonic, fog, or other signal apparatus for the protection of ships
or vessels has been much impaired by the absence of any known mode of or suitable
apparatus for indicating accurately the direction or position of the sound of the
siren, horn, whistle, or other signal, so that those on board of any ship or vessel
seeking guidance in thick and stormy weather have been altogether uncertain as to
the direction or location of the sound, and consequently much valuable time has
been lost, and in many cases ships have been unable to steer clear of the danger
from which the said signal was designed to protect them.
Now it is known that the sound of phonic fog signals is much more intense in the
line of the axis of the same than in any position outside of this line. We have by
experiment ascertained that this axis can be obtained by means of a trumpet applied
to the car or cars, and the direction and location of the signal may be determined
by others who require warning or direction by distant sounds.
The axis of the sound is ascertained by sweeping the horizon with the trumpet
until the line of the greatest intensity is found, which will be the axis of the trumpet
or signal, and thus determining the direction and location of the signal.
For the purpose of perfectly securing the advantages of this discovery we have
made a novel apparatus in the form of an ear trumpet.
The said apparatus has a bell or trumpet-shaped mouth whose inner surface forms
a portion of a parabola, or rather we prefer it should have this form as the same
produces the best effect, but this form may be modified if necessary or desirable.
This bell or trumpet-mouthed piece has extending from it two tubes which are of
the proper form, to extend to and fit into the ears of any person using the said
[Price Gd.]

page_text: apparatus, and are provided with any suitable car tips to fit conveniently into the
orifice of the ears and exclude as much as possible all sounds to the said tubes.
These tubes extend through opposite sides of the said trumpet-mouthed piece of
the apparatus and terminate in a rather wide orifice or mouth which is presented
to the centre of the interior portion of the bell or trumpet mouth. The object of
this arrangement is that the whole of the sound collected by the bell or trumpet
mouth shall by the interior surface of the same be reflected into the orifice or mouth
of the tubes, and thereby conducted directly to the ears of the listener.
The car tips are preferably provided with flanges hollowed out to cover the cars
and exclude as much as possible all local sounds. The ear tips are also made to
adjust to any size of head by springs. The re-inforcing bell may have its mouth
elliptical instead of circular.
The apparatus may, if necessary, be provided with a cover of felt or other
substance which is a bad conductor of sound.
We may modify the above described construction of our apparatus by making it
somewhat in the form of an ordinary trumpet, with the two ear tubes extending
from or forming continuations of the same. Or we may otherwise modify the shape
and construction of the said apparatus so long as the essential features thereof,
namely, the combination of the two tubes with the bell or trumpet mouth or sound
receivers, is retained. Or we may use a cylinder into which the head may be
introduced, and sound admitted to cars from open end of cylinder only.
The said apparatus may be fixed on board ship, or on life-boat stations, lighthouses,
and be arranged to turn on a pivot or otherwise.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said John Stewart Wallace and Edward Tucker in the Great Seal Patent
Office on the 13th October 1876.
JOHN STEWART WALLACE and EDWARD TUCKER, both of Belfast, in the County of
Antrim. "AN IMPROVED EAR TRUMPET."
The usefulness of acoustic or phonie fog or other signal apparatus for the
protection of ships or vessels at sea has hitherto been much impaired by the absence
of any known mode of or suitable apparatus for rendering andible sounds that are
inaudible to the naked ear, and indicating accurately the direction or position of
the siren, horn, whistle, or other signal or sounder so that those on board of any
ship or vessel seeking guidance in thick and stormy weather have been altogether
uncertain as to the direction or location of the sound; consequently much valuable
time has been lost and in many cases.ships have been unable to steer clear of the
danger from which the said signal was designed to protect them, and shipwrecks
and great loss of life and property have ensued.
Now it is known that the sound of acoustic or phonic signalling apparatus is
much more intense in the line of the axis of the same than in any position outside
of this line. "We have, by experiment, ascertained that this axis can be accurately
found by means of a trumpet or acoustic instrument or apparatus applied to the
ear or ears, and the direction and location of the signal may be thereby determined
by those who require warning or direction on board ships or vessels.
The axis of the sound is ascertained by applying the said instrument to the ears,
and "sweeping" the horizon with the same, that is to say, turning it to various
points until the line of the greatest intensity of the sound, which will be the axis
of the fog horn or other sounder, is found, thus determining the direction and
location of the signal.
For the purpose of perfectly securing the advantages of this discovery we have
devised and constructed the novel apparatus herein after described, and which is
illustrated in the accompanying Drawing.

page_text: Figure 1 is a plan of one form of our improved ear trumpet or acoustic
instrument.
Figure 2 is a side view, and Figure 3 a front view of the same.
Figure 4 is a plan of another of our said instruments of slightly modified con-
struction.
Figure 5 is a plan drawn to a reduced scale of another modification of our
invention, shewing the instrument provided with only one ear tube.
Like letters indicate the same parts throughout the Drawing.
The said apparatus or instrument, in all the forms or modifications in which it
may be constructed, has a mouth or sound receiver, which may be constructed as
shewn in Figure 1, or may be bell or trumpet shaped, with an interior surface of
any suitable form for receiving or collecting sound. We believe the best results
will be obtained by having the interior of the said mouthpiece of a parabolic form,
but we may, if desired, construct it of any other suitable form. And the said
instrument or apparatus. has the mouth or sound receiver and ear tubes or con-
ductors so formed and arranged that the whole of any sound received or collected
in the said mouth will be reflected into the said tubes, and thereby conducted
directly to the ears of the person using the said instrument.
The instrument shewn in Figures 1, 2, and 3 of the Drawing embodies our
Invention in what we consider the best form of the same. Its mouth a is made
with adjustable sides a¹, so that the area of the orifice of the said mouth can be
increased and diminished at will, and the person using the said instrument may
first sweep the horizon with the mouth open to its full width, and then having dis-
covered the sound or ascertained the direction of the sound, can contract the mouth
to diminish the intensity, and more accurately localize the sound. This enlarge-
ment and diminution might be effected by means other than those we have shown,
but we use the latter in preference to any other devices for this purpose; that is
to say, we construct the mouth of a rectangular form, its sides a being longer
than the sides a², all four of these sides being of a parabolic form. The top and
bottom sides a are fixed or immovable, but the sides a¹ are hinged or jointed at b
to the central portion of the instrument. At the outer edge of the parts a² is a
slot or aperture c, through which project studs. or pins d fixed in the movable
sides a¹. To these studs are jointed arms or links e, which extend to a central
stud f which projects through and slides in the slot f* in the part a², provided with
a pinching or tightening nut f¹. When this nut is slackened the said stud may
be moved freely in its slot, and by so moving it the sides a¹ of the mouth may be
opened or closed, and then by tightening the said nut these sides may be secured
in the position to which they have been adjusted.
Instead of hinging the sides a¹ so that the same may be opened and closed to
expand and contract the mouth, we may construct the instrument with immovable
sides, and provide the front of the mouth with hinged or sliding doors, whereby the
area of the mouth of the instrument may be increased or diminished for the pur-
pose above set forth.
And we sometimes make the mouth elliptical.
We may provide each instrument with a set or series of mouths of different
shape and dimensions fitted to the said socket, so that either one or the other may
be inserted according to the circumstances or conditions under which the instrument
is to be used. Or if one mouth should be injured it may be immediately replaced
by another.
means.
t
In the above described instrument the central portion of the mouth is fitted
removably in the socket g, and is secured therein by screws h or by other suitable
This construction of the instrument allows the said mouth to be separated
from the other portions of the instrument, and affords great convenience in packing
the same.
The ear tubes i are also secured detachably upon the flanges; by
means of bayonet joints at j¹, or by other suitable fastenings, and may therefore be
detached or separated from the other part of the instrument when it is necessary
or desirable to pack the said instrument in a small space, or to repair the said tubes

page_text: or exchange them for others. We may in some cases provide the said instrument
with a diaphragm or membrane of skin or other suitable material placed in the
mouth near the orifice of the car tubes to increase the effect of the sound.
If desired we may provide the said apparatus or instrument with a.cover of felt
or other material, which is a bad conductor of sound.
The ear pieces are preferably formed as shewn in Figure 1, that is to say, they
are formed with tubular shanks extending into the ends of the tubes i, and
formed with a small collar or piston to fit and slide within the end of the tube
as shewn.
Between this piston and the flange in the tube we place a spiral
spring, which tends always to press the ear piece outward. The said ear piece
is formed with an outside flange furnished with a pad or cushion, which is
designed when the instrument is used to cover the whole of the external portion of
the ear, and thereby entirely, or as nearly as possible, to exclude sounds other than
those entering by the mouth or receiver. The said pads or cushions are preferably
formed of india-rubber, and stuffed inside the same with wool. The said spiral
springs permit these pads or cushions to adjust themselves closely to the ears when
the tubes are held in the proper position. We may employ instead of these soft
pads or cushions ear tips formed to enter the orifice of the ear, but we do not con-
sider the latter either so convenient or so effective for the exclusion of local sounds
as the former. The handle is so formed and arranged as to afford the means
whereby the person using the instrument may conveniently hold and adjust the
same.
In Figure 4 we have shown one of our improved instruments constructed with a
trumpet-shaped mouth a, which is attached permanently to the ear tubes i, that is
to say, the said trumpet mouth and tubes are made in one piece.
We prefer that the said tubes should be extended and meet inside the mouth or
orifice, and provided with one common aperture at i¹.
In Figure 5 we have shewn a modification of our Invention, wherein we provide
the said instrument with only one ear tube i. This tube is provided with an
adjustable and padded ear piece k to be applied to one ear as above described. And
it also has a pad or cushion m supported on a spring clip n or other device for
closing the other ear.
It will be observed that our improved instrument is so constructed and arranged
that when in use the mouth or orifice a of its sound-receiving portion extends
forward in front of the face of the person using the said instrument so that he looks
toward the point from which the sound is heard, or in which he is secking for the
sound.
We may further modify our said Invention by forming the said instrument with
a separate mouth or sound receiver for each ear tube. Or we may otherwise
modify the shape and construction of the said apparatus so long as the essential
features thereof, namely, the combination of the two tubes with the bell or trumpet
mouth or sound receiver, is retained. Or we may use a cylinder, into which the
head may be introduced and sound admitted to ears from open end of cylinder
only. The said apparatus may be fixed on board ship or on life boat stations,
lighthouses and in other places, and be arranged to turn on a pivot or otherwise;
that is to say, we may mount the said apparatus or instrument upon a stand or
frame by a ball-and-socket joint or other connection, which will allow the free
adjustment of the instrument in all directions for the purpose above specified.
Although we have above described our said Invention more especially in con-
nection with its use on board ships, it will be obvious that the same will be equally
useful for military and other purposes where it is desirable to detect the existence
or direction of distant sounds.
Having thus fully described our said Invention, and the manner of performing
the same, we wish it understood that we claim for the purposes berein specified―
First. An ear trumpet or acoustic instrument constructed with double tubes, that
is to say, with tubes extending from opposite sides of its mouth, and properly

page_text: formed and arranged to conduct the sound from the said mouth to the ears of the
person using the said instrument.
Second. Constructing the trumpet mouth or sound-receiving portion of the said
instrument with an elliptical or a rectangular area or orifice, and with its interior
surface inclined from the said orifice inward in a parabolic or similar form.
Third. The trumpet mouth or sound receiver so constructed that its area or
orifice may be increased or diminished.
Fourth. An acoustic instrument or ear trumpet so constructed that when in use
its mouth or sound-receiving orifice projects forward before the face and toward
the point from which the sound is heard, or in the direction in which the sound is
being sought.
Fifth. Providing the said instrument with a series of detachable mouths as above
described.
Sixth. Providing the ear tubes with adjustable ear pieces.
Seventh. Providing the said ear pieces with flanges covered with india-rubber
or other soft material adapted to close the ears and exclude all local sounds.
Eighth. Constructing the said instrument with detachable or removable ear
tubes as above set forth.
Ninth. The ear trumpet or acoustic instrument provided with the adjusting
mouth, the detachable ear tubes, and the self-adjusting and padded ear pieces as
shewn in Figures 1, 2, 3, of the Drawing, and as above described.
Tenth. The modification of our Invention consisting of the single tube to be
applied to one ear, and the pad or other stopper for the other ear, supported on a
spring or otherwise, as above set forth.
Eleventh. The apparatus consisting of the said car trumpet or acoustic instru-
ment mounted upon an adjusting frame or stand as above set forth.
In witness whereof, I, the said John Stewart Wallace, for myself and on
behalf of the said Edward Tucker, have hereunto set my hand and seal,
this Fourth day of October, in the year of our Lord One thousand eight
hundred and seventy-six.
JOHN STEWART WALLACE. (L.S.)