Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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HEARING COUPLER SHELLS OF SOFT PLIABLE THERMOPLASTIC MATERIAL
The present invention relates to a shell for a sound altering device for use
in the
auditory canal of a human user. In some instances, the device is used to
amplify
sound perceived near the user's ear, in other instances the device will be
used to
contain a receiver for receiving remote sounds, and, in a yet third instance,
the device
will be used to deaden sound perceived at the user's ear. More particularly,
the
invention relates to such an electronic coupler which is positioned in a shell
which fits
in the ear and may be either custom molded for a particular user or may be a
stock
item. Even more particularly, a soft pliable thermoplastic material is used to
form the
shell.
BACKGROUND OF THE ART
Electronic hearing couplers are known in the prior art. Recent developments
in the electronic arts have made such couplers smaller. Reference is now made
to
Figure 1, which shows in sectional view many of the relevant structures in the
ear 10
of a human user. It is now known to position such couplers directly into the
external
auditory canal 12, also known as the meatus. The external ear 14, also known
as the
pinna, is a trumpet-shaped structure which funnels sounds into the meatus 12,
a
relatively short tube which traverses an opening in the temporal bone 16 and
terminates
at its internal end at the tympanic membrane 18, or eardrum. Surrounding the
opening
of the meatus 12 into the pinna 14 are a variety of structures, including
(from the front
and moving downwardly in a clockwise direction when viewed from the exterior}:
the
tragus (not shown in the sectional view), the antitragus 20, the antihelix 22
and the
concha 24. These structures effectively form a bowl-like depression in the
pinna 14 and,
in combination with the meatus 12, a unique configuration is provided for each
individual, and, in fact, each ear of each individual. In persons requiring
hearing
amplification, it is necessary to provide a clean auditory signal proximate to
the
tympanic membrane 18. In the past, the technique has been to seat an
electronic
hearing coupler in a rigid thermoplastic shell, typically made of an acrylic
material, with
controls andlor battery access provided in a faceplate at the exterior end of
the shell.
While providing an acceptable auditory signal, the rigid shell can allow sound
leakage
in an annular space between it and the meatus. It can also be uncomfortable to
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wearer. It is therefore an advantage of the present invention to deliver an
improved
auditory signal to the tympanic membrane in a more comfortable manner.
SUMMARY OF THE INVENTION
This and other advantages of the present invention are provided by a device to
be inserted in an auditory canal of the ear of a human user. Such an auditory
canal is
surrounded at an external end by a conchs which is in tum surrounded by a
pinna and
bounded by a tympanic membrane at an internal end thereof. The device
comprises
a shelf with a generally cone-shaped exterior defined by a larger end for
positioning
toward the external end of the auditory canal and a smaller end for
positioning toward
the internal end of the auditory canal with at least one internal passage
communicating
the larger end with the smaller end. The shell is formed from a material
selected from
the group consisting of soft thermoplastics ("STP"), thermoplastic elastomers
("TPE"),
thermoplastic rubber ("TPR") and any combination of the foregoing.
In some embodiments the shell is a continuous matrix of the material, while in
others the material is foamed to provide a plurality of closed cells
throughout the matrix.
The preferred hardness is less than 80, measured on the Shore A scale,
although
hardness as low as 2 may be useful.
In some embodiments, the shell is custom made to specifications set by an
impression of the auditory canal of the intended human user, while in other
situations
the shell is made as a stock item to specifications set by one of a plurality
of generic
sizes useful to a representative sample of the population.
In some embodiments, the shell fits entirely within the auditory canal of the
user,
while in other cases, the external end of the shell fits within the conchs of
the ear of the
user. In either case, the exterior of the shell compresses to be frictionally
retained in
the auditory canal of the user.
The shell may contain at least one electronic device selected from the group
consisting of: a button receiver, a sound amplification device, a sound box
and a radio
receiver to provide a auditory signal for the user. In some cases, a shell is
communicated to an electronic device positioned external to the ear, typically
behind
the pinna.
Some embodiments further comprise a ring-like element sealingly fitted around
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the circumference of the shell from the internal end as the device is fitted
into the ear
of the user.
In yet another embodiment, the soft pliable shell encloses a rigid hearing
device
worn behind a pinna of a human user. In such a case the shell is formed from a
material selected from the group consisting of soft thermoplastics ("STP"),
thermoplastic
elastomers ("TPE"), thermoplastic rubber ("TPR") and any combination of the
foregoing,
with a Shore A hardness of less than 8. These last embodiments may be brightly
or
decoratively colored and shaped to express the personality of the wearer, as
well as
providing more comfort.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is best understood when reference is made to the accompanying
drawings, wherein identical parts are identified with identical reference
numerals, and
wherein:
FIGURE 1 shows a sectional view from the front of a human ear;
FIGURE 2 shows a sectional view of a human ear containing a first embodiment
of the present invention device;
FIGURE 3 shows the device of Fig. 2 as viewed from the side, exterior to the
ear;
FIGURE 4 shows the device of Fig. 3 as viewed from the side, interior to the
ear;
FIGURE 5 shows a prior art device in a human ear;
FIGURE 6 shows the device of Fig. 5 as viewed from the side, exterior to the
ear;
FIGURE 7 shows a sectional view of a human ear being fitted for a hearing
device;
FIGURE 8 shows a male mold created for a particular human ear;
FIGURE 9 shows the making of a female mold for creating a soft pliable shell
of
the present invention;
FIGURE 70 shows a resulting raw shell of the present invention;
FIGURE 11 shows a sectional view of a human ear containing a second
embodiment of the present invention device;
FIGURE 12 shows an enlarged sectional view of the second embodiment
hearing coupler shell;
FIGURE 13 shows an enlarged sectional view of a variation on the second
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embodiment hearing coupler shell;
FIGURE 14 shows an additional element being used with the embodiment of Fig.
13;
FIGURE 15 shows an embodiment of the present invention wherein a soft pliable
ear insert is used in combination with a hearing device worn behind the pinna;
FIGURES 16 through 20 show six different variations on an embodiment of the
present invention wherein the invention comprises a soft pliable shell for a
rigid case
worn behind the pinna of a human user.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 has shown the internal ear structures of a human without a device 100
as in the present invention. In Figure 2, a device 100 of the present
invention is shown
in place in the ear 10; in Figure 3, a side view of the device from the
exterior of the ear
is provided and in Figure 4, a side view from the interior of the ear is
shown. The
device 100 has a shell 102 of a soft pliable material. It receives and retains
an
electronic auditory coupler (not shown in this figure) in its generally cone-
shaped hollow
body, which is seated in the meatus 12 of a human user. At a larger end 104 of
the
cone-shaped shell 102, typical items are provided when the device 100 is
intended for
hearing amplification. These include a microphone input 106 to receive sound,
a
volume adjustment control 108 and a battery access port 110. These items are
best
viewed in Fig. 3, which is the view as taken from the exterior of the ear.
When the
device 100 is viewed from the smaller end 112, which is inserted into the
auditory canal
12, a sound aperture 114 is provided to allow amplified sound generated in the
device
100 to be directed at the tympanic membrane. Viewed from the larger end 104,
the
shell 102 is seen as tapering in a somewhat upwardly direction, terminating in
a small
opening 114 at the smaller opposite end 112. One side of the shell 102 is
generally flat,
to fit against the bony structures of the temporal bone near the antihelix and
the right
side of the shell is much more curved, to generally fit against the tragus,
which is the
cartilaginous knob at the front side of the ear, and which curves dorsally
somewhat to
shield the opening of the meatus 12. At the larger end 102, the top portion
fits with the
conchs and the lower portion nestles behind the slight flap of the antitragus,
which also
serves a shielding function to the meatus.
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Attention is now directed to Figs, 5 and 6, which show a prior art device 200,
viewed in a sectional view in Fig. 5 and in a external side view in Fig. 6.
While the rigid
thermoplastic shell 202 lines the meatus 12 and allows a electronic auditory
coupler to
be inserted therein, with a flexible tube (not shown) on the coupler directing
an auditory
signal to the small opening 214 which is proximate to the tympanic membrane
when
inserted in the ear, this shell has several distinct disadvantages, each of
which
becomes quickly known to a user. First, the need to easily position the shell
202 into
the meatus mandates a slightly loose fit, such as is shown at the point
indicated by
reference numeral 215. There is inevitable sound leakage around the shell 202
in an
annular region defined by the exterior surface of the shell and the internal
surface of the
meatus. The rigidity of shell 202 is not commensurate with the motions of the
auditory
system and particularly the slightly upturned meatus which occur during
speech,
mastication of food, yawning, and even general movements of the head. The
rigidity
of the shell 202 results in either discomfort to the wearer, movement of the
device, or
both, when these activities occur. The rigid shell 202 is unable to cushion
blows or
impacts to the head. The rigid shell 202 necessitates meeting tight tolerances
when
molding and then mating the shell up with a faceplate to the larger end 204.
The rigid
shell 202 has little or no capacity to be properly fitted to the percentage of
the
population who have ear canals which vary from the normal in their degree of
convolution. The prior art device 200 is provided with the same external
controls at the
larger end 204, as shown in Fig. 6: a microphone input 206 to receive sound, a
volume
adjustment control 208 and a battery access port 210.
For at least these reasons, the advantages of the present invention soft
pliable
shell 102 over the traditional hard plastic shell 202 include the following: 1
) reduction
of the common phenomenon known as the occlusion effect which occurs when the
ear
is plugged or blocked; 2} a better fit in the ear and the ear canal which
reduces the
likelihood of acoustic feedback; and 3) the reduction in amplified sounds
emanating by
conduction through the mandible, facial bones and tempromandibular joint.
These
acoustic effects are well known as a source of annoyance and discomfort to the
user
of a hearing assistance device.
As mentioned above, a first embodiment of the invention will be a hearing
coupler in a soft pliable shell 102 custom manufactured for a specific user.
Figures 7
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through 10 show the steps involved in making such a custom manufacture. The
first
step in making such a device is the step of obtaining a positive impression of
the
external ear and the external auditory canal or meatus. The process of
obtaining such
an impression is generally well-known and conventional techniques for making a
positive impression, also referred to as a male mold, will be known to one of
skill in this
art. in Figure 7, a mass of the molding material 250 is shown inserted in the
ear and
specifically in the meatus and conchs, where it is accommodated to the size
thereof.
In Figure 8, the formed male mold 260 is removed for processing. However, the
invention is not limited to the use of such conventional techniques involving
the
insertion of the impression-making materials into the ear of the intended
user, and, as
the techniques become more readily available, it would be expected that the
male mold
260 could be created from a computer model based upon laser interferometric
readings
of the relevant ear structures, just to give one example. A common material
for the
impression will be a silicone material, but the computer generated mold may
comprise
a different material, since it would never have to be physically present in
the ear.
The second step in the process is to conform the male mold 260 to the
requirements of the finished custom shell. Primarily, this step will involve
the trimming
and/or buffing of the surfaces to remove rough spots or edges, filling in any
deformations or cracks with a melted wax, and coating the male mold with a
thin layer
of a silicone which will cure at ambient temperatures, to further smooth the
surface and
fll in imperfections.
The third step is shown in Figure 9, with the preparation of a female mold 265
from which the pliable shell of the present invention will be made. A variety
of
acceptable techniques are known. The first of these is to place the male mold
260 into
a sturdy chamber for receiving a molten material, typically a thermoplastic,
which will
become the female mold. The chamber must be of a material which may be easily
separated from the female mold, once the latter is formed. To assist in this,
it will be
conventional to coat the internal surfaces of the chamber with a mold release
compound, of which selection is relatively easy once the respective materials
of the
chamber and female mold are determined. Once coated internally, the chamber
should be attached to a injection molding apparatus and the molten molding
material
injected under pressure to completely fill the space between the chamber and
the male
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mold. In a variation on this step, the mate mold will be placed in a molding
chamber
and coated to a depth of at least 0.5 inches with an epoxy-type resin as is
commercially
available, particularly a two-part epoxy resin which is mixed at the time of
use. The
coated male mold is then placed in either a compressive assembly or a vacuum
assembly, the purpose of either to assure close conformity of the curing epoxy
resin to
the male mold. !n yet a third variation, a two part urethane polymer is coated
to a depth
of at least 0.5 inches atop the male mold, and the curing polymer subjected to
either
compression or vacuum to conform the female-mold-forming compound to the male
mold. In the practice of some of these techniques, it may be useful to heat
the chamber
while it is subjected to compression or vacuum as the polymer of the female-
mold-
forming compound sets up, In other known techniques, particulartly employing
an
exothermic curing reaction, it may be preferred to cool the chamber, typically
with water
flow therearound. The specific need for heating or cooling will again be known
to one
of skill in this art.
After the female mold has been formed so that it effectively envelopes the
male
mold and has cured fully, the female mold is removed from the chamber, also
removing
the male mold. The male mold is then removed from the female mold in a manner
which allows subsequent use of the female mold to form the shell. Particularly
important is the need to provide an opening for inserting a dummy member and
injecting the thermoplastic material from which the shell will be formed. The
dummy
member will have the same (or slightly larger) dimensions as the hearing
coupler which
will ultimately be inserted. Unlike the female mold, which will be custom made
for an
individual user, the dummy member may be mass-produced, since the electrical
components constituting the hearing coupler will be effectively generic.
Repairs may
be made to the female mold if necessary using a two-part epoxy resin or other
suitable
agent. Buffing using a sandpaper/metai wheel or a dremel will also be known.
The
dummy member should be coated with an appropriate mold release compound prior
to
insertion in the cavity left by the male mold in the female mold. The dummy
insert
should be aligned in the cavity in a manner which will render the hearing
coupler
>0 insertible in a functional arrangement.
The next step is to place the female mold containing the aligned dummy insert
into a chamber for injection of the pliable shell-forming material into the
space between
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the female mold and the dummy member. Once so inserted, a thermoplastic
material,
which will solidify to have a Shore A durometer hardness of less than about 80
(and
preferably less than about 65), is injected into the space to form the soft
pliable shell.
Materials which are acceptable for this shell are disclosed in more detail
below. The
injection molding technique is known to be amenable to having synchronous
injection
of more than one material into a single mold to yield a product which has
mixed
composition.
Once the injected thermoplastic material has solidified into the custom shell,
this
shell is separated from the female mold and the dummy member. As with the
molds
from which it came, the molded pliable custom shell should be inspected for
surface
defects and smoothed or buffed to correct such defects. The shell, shown as
275 in
Figure 10, is ready for further processing.
A cavity 280 will remain in the shell where the dummy member was removed.
The hearing coupler, customized for the individual user if necessary, is
inserted into the
cavity in its operative configuration and fixed into place. A variety of means
may be
used for affixing the coupler in the shell cavity, including mechanical
affixation or
latching, adhesion using an adhesive agent, or heat welding. In any case, the
hearing
coupler will be effectively restricted from movement within the shell after
this step has
been practiced.
30 FIGURE 11 shows a second embodiment device 300 of the present invention in
place in the ear 10. The device 300, which is sectioned to show internal
components,
has a shell 302 of a soft pliable material. It receives and retains an
electronic auditory
coupler system 303 in its generally cone-shaped hollow body, which is seated
in the
meatus 12 of a human user. At a larger end 304 of the cone-shaped shell 302,
typical
'S items are provided when the device 300 is intended for hearing
amplification. These
include a microphone input 306 to receive sound, a volume adjustment control
308 and
a battery access port 310. At the smaller end 312, amplified sound is directed
into the
meatus, although a plurality of apertures 31 fi are provided instead of a
single aperture,
as will be explained below. As with the first embodiment, the shell 302 is
seen as
0 tapering from the larger end 304 toward the smaller end 312, although this
embodiment
shell is much more uniform in shape. It will also be immediately noted that
this second
embodiment shell 302, at least in the preferred embodiment shown, is
significantly
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smaller, so that it presents an "in the canal" version of the hearing device.
This is a very
desirable objective in many situations where the device is intended to be made
as
inconspicuous as possible.
Since the object of the second embodiment is to provide a stock item of
commerce, the impression which will be made is not intended for use with just
one
particular individual. Therefore, while a series of persons may be used to
generate a
series of left and right ear impressions having various sizes and
configurations, it is also
possible that the male molds produced from the first step described above may
be
actual impressions, but they may also be created by an artisan skillful in
creating such
molds, or even from a computer-generated mold. Once formed, by whatever
method,
the male mold will be used to create the female mold and the soft pliable
shells having
an internal cavity sized and shaped to receive a hearing coupler.
When this second embodiment method of the invention is practiced, it would be
highly preferred to use materials for the male mold, the female mold and the
dummy
insert which permit them to be used multiple times, as it is only through this
multiple use
that the overall cost of producing the stock shells is sufficiently reduced to
justify them
over the custom molding method. However, in all other aspects, the production
of the
stock shells is identical to the production of the custom soft pliable shells
as described
in detail above. It may be preferred to impart some identifying indicia in the
stock
shells, particularly in the surface of the cavity for receiving the hearing
coupler, which
facilitate the quick determination of size and or orientation (left or right
ear).
Just as a method of manufacture of the present invention device has been
described wherein injection molding has been used, it would also be within the
scope
of the invention to form a parison of the material being molded and to use
conventional
blow molding techniques to form the soft pliable product. Materials having the
softness
(as determined by the Shore A test method) required of the product will also
be
amenable to being formed in a conventional transfer molding process, using
conventional molds as will be known to one of skill in this art.
The hearing coupler to be inserted in the shell is not really an inventive
aspect
of the present invention. In addition to a hearing coupler, it is possible to
put a variety
of electronic devices in the shells 102, 302 of the present invention. For
example, it
would be known to put items such as a button receiver, a sound amplification
device,
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a sound box and a radio receiver in the shell 102, 302.
The embodiment of the invention shown in Figure 11 is shown in an enlarged
sectional view in Figure 12. In this embodiment, the single axial opening at
the smaller
end has been replaced with at least one axially positioned aperture 316, and
preferably,
a plurality of the apertures 316 are used, as is actually illustrated. These
axial
apertures 316 are near the smaller end 312 instead of being directly at the
smaller end.
The intention of this configuration is to reduce the accumulation and
retention of ear
wax or cerumen. This radial aperture or apertures is also more easily cleaned
of wax
and other deposits than a single axial aperture. In the embodiment shown, the
hollow
interior of the shell is divided by the shell material into a chamber 318 for
receiving the
electronic device and a sound emanation chamber 320, which terminates in the
axial
apertures 316. In an alternate embodiment, a further sound transmission
chamber 322
is provided between the chambers 318 and 320. This chamber 322 eliminates a
flexible
tube used in many prior art devices for transmitting sound from a sound box to
the
sound aperture. While flexible, such a tube would be more rigid than the shell
302 in
these preferred embodiments of the invention and may prevent it from achieving
the full
adavantages of the soft pliable material.
In a yet further embodiment of the invention, FIGURE 14 shows shell 302, prior
to insertion in an ear, with a ring-like element 400. This ring-like element
400, which
will typically be much more rigid than the shell 302, is sealingly fitted
around the
circumference of the shell from the smaller or internal end 312 as the shelll
is fitted into
the ear of the user. The pliable nature of the shell 302, particularly along
its
intermediate portion identified as 324 in Fig. 14, allows the overall
combination of ring-
like element and shell to be more firmly seated in the meatus. While ring-like
element
may be a right cylinder, the more preferred embodiment, as shown in Fig. 14,
is
somewhat frusto-conical, so that one end 402 is smaller in diameter than the
opposing
end 404. Because this element is inherently rigid, it will generally have a
very thin wall,
which will, in proper cases, provide a certain amount of resilient or
restorative action to
facilitate seating.
The preferred elastomeric materials for forming the shell of the present
invention
would include the class of soft thermoplastics ("STP"), thermoplastic
elastomers
("TPE") and thermoplastic rubbers ("TPR") having a Shore A hardness of less
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and preferably covering a hardness range from about as low as 2 Shore A , but
preferably in the range of from about 30 Shore A to about 65 Shore A. These
would
generally include styrenic block copolymers, polyolefin blends (TPOS),
elastomeric
alloys, thermoplastic polyurethanes (TPUS), thermoplastic copolyesters,
thermoplastic
polyamides, EPDM and others which will known to those of skill in this art. In
one
specific embodiment of this invention which meets the above criteria, the soft
pliable
shell would comprise a thermoplastic elastomer sold commercially by Advanced
Elastomer Systems of Akron, Ohio, under the trademark SANTOPRENE~. As
understood by the inventors from information commercially available on the
preferred
material, the SANTOPRENE~ polymer is an ethylene-propylene copolymer.
While the embodiments presented so tar of the present invention describe a
hearing device for the ear in which the entire hearing coupler electronics are
contained
in the shell, there are situations where the amount of amplification, etc.,
simply does
not permit this. In such a situation, as is illustrated in FIGURE 15, the
shell 502 inserted
into the ear contains no electronics, volume control or battery. All of the
hearing
electronics are contained in a case 550, generally a rigid plastic material,
which can be
positioned around the rear side of the pinna of the user. A flexible tube 552
transmits
the amplified sound into a port 506 which would be typically replace the
microphone
port 306 of the embodiments described before. Port 506 would communicate the
sound
through a single passage 554 to a sound aperture 514, analogous to aperture
114, 214
or the like. IN some of these situations where the size of the case 500
effectively
precludes it from being inconspicuous, it may be preferable by some users of
the device
as shown in Fig. 15 to have a pliable shell 602, in which rigid case 550 may
be housed.
Some variations on this concept are presented in Figures 16 through 21. While
the
generally accepted practice in forming the ear insert type of devices such as
shells 102,
202, 302 and 502 to simulate skin color to minimize their visbility, it may be
just as
important in the case of pliable shell 602 for covering an already visible
rigid case 550
to make the shell 602 readily visible and even conspicuous. For that reason,
colors,
and even bright colors may be the normal mode of practice. To run through some
of
the possible variations, Figure 16 shows a shell 602 which would resemble a
telephone
receiver, Figure 17 shows a shell 602 which would resemble a banana, Figure 18
shows a shell 602 which would resemble a caterpilier, Figure 19 shows a shell
which
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would resemble a butterfly, Figure 20 shows a shell 602 which resembles a
hockey
stick and a puck and Figure 2shows a shell 602 which resembles a baseball bat
and
ball. Although not specifically illustrated, team colors and logos could be
licensed for
use, as could popular characters and the like. Even though the shells 602 have
a clear
function of expressing the personality of the wearer, the soft pliable nature
of the shell
also increases the comfort of wearing the device and protects a senstive area
of the
body where the bone lies below a thin skin surface.
Although the present invention has been described above in detail, the same is
by way of illustration and example only and is not to be taken as a limitation
on the
present invention. Accordingly, the scope and content of the present invention
are to
be defined only by the terms of the appended claims.
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