Note: Descriptions are shown in the official language in which they were submitted.
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1
METHOD OF PRODUCING HEARING AIDS AND A HEARING AID
The present invention relates to a method as set forth
in the preamble of claim 1 and to a hearing device as
set forth in that of claim 9.
Two-component or multi-component injection-molding
methods are known from plastics processing technology.
Reference can be made, for example, to Ch. Jaroschek
"Das Mehrkomponenten-Spritzgiessverfahren" [Multi
Component Injection-Molding] in Swiss Plastics 19
(1997) No. 12, or to U. Stenglin "Hart/Weich
Verbindungen and anwendungsbezogene Modifizierbarkeit
von TPE-S (SEBS/SEPS)" [Hard/Soft Compounds and
Application-Related Modifiability of TPE-S (SEBS/SEPS)]
in Swiss Plastics 20 (1998) No. 3. These discuss the
advantages of two-component or multi-component
injection-molding, specifically those relating to tool
costs, personnel costs, machine costs and material
costs. The methods mentioned are basically categorized
into sandwich injection-molding methods and overmolding
methods. In the present case, it is the overmolding
method which is of principal interest, albeit not
exclusively so. In said method, a part is formed from a
first material component, and a second, different
material component is then injected over at least some
areas of the first material component, by which means
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the second part made of different material is built up
on top of the first part. A11 injectable thermoplastics
can be used, in particular also for the overmolding
method, but also, quite specifically, nonconnectable
further materials.
Of course, the abovementioned costs are also important
production factors in the production of hearing
devices. In addition, however, in the production of
hearing devices, there is the basic problem of space,
since a permanent requirement of said branch is to
achieve the most space-saving constructions.
The object of the present invention is to propose a
production method and, correspondingly, a hearing
device resulting from this method, said method
permitting a significant increase in the packing
density of hearing devices.
To this end, it is proposed, in said method, that at
least two of the parts to be assembled on the hearing
device are produced by two-component or multi-component
injection-molding and assembled together. The advantage
possibly ensuing from this, namely a reduction in the
aforementioned costs, is of course greatly welcome,
although a more important point is that using said
method achieves the essential criterion for hearing
device construction, namely that of increasing the
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component density per cm3 of available space.
If, according to a preferred embodiment of the method
according to the invention, one of the parts used is at
least a portion of the hearing device housing, for
example one shell of a two-shell housing, then it is
possible to build directly onto the latter, using two-
component or multi-component injection-molding, further
active parts, in particular seals, for example for
tight connection to the second shell of the housing
and/or impact-damping recesses for receiving delicate
components and/or further active hearing device
components such as acoustic leads. In principle, this
affords the possibility of dispensing with connection
elements between said parts, which connection elements
are necessary in conventional types of construction, or
of giving such parts only the exact volume necessary
for their function, without however having to provide
any connecting portions such as grooves and webs.
As has been stated, in a preferred embodiment of the
method according to the invention, in principle at
least one seal is built up in connection with the two-
component or multi-component injection-molding,
together with a further part directly adjoining the
seal, for example and preferably a housing part, or an
operating member projecting through the housing, or a
further hearing device part which itself has to be
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sealed off especially precisely.
In a further preferred embodiment of the production
method, in particular for hearing devices worn outside
the ear, it is proposed that the acoustic lead at the
output of the electro-mechanical transducer, which
acoustic lead is usually designed as a plastic tube, be
produced in said injection-molding method, either
together directly with a housing portion or, for
example, with an elastic, form-fitting, sealing fixture
to be inserted into a seat in the housing.
In a further preferred embodiment of said method, it is
proposed that an acoustic lead at the input of the
acoustic-electric hearing-device transducer be produced
in said injection-molding method, for example either
again together with a portion of the hearing device
housing, or with a specifically designed, for example
sealing, elastic fixture. In further embodiments of the
method according to the invention, which can of course
each be used individually or in combinaton with other
preferred embodiments, receiving seats for hearing
device components or parts are produced in said
injection-molding method, either together with housing
portions andlor together with other structural parts
directly adjoining them.
In a further preferred embodiment, predetermined
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surface areas on the outside of the housing are
produced together with the housing, but from different
material, in said injection-molding method, for example
for design reasons and/or to make it easier to feel,
just with the fingers, the operating members arranged
on the housing.
A hearing device according to the invention is
distinguished in accordance with the characterizing
part of claim 9, and preferred embodiments in
accordance with claims 10 through 16.
The invention is explained below by way of example with
reference to figures, where:
Fig. 1 shows a diagrammatic and perspective view of a
portion of a hearing device housing, with a
seal built on in accordance with the invention.
Fig. 2 shows a cross section through a part of the
housing in Fig. 1, with the seal built on in
accordance with the invention.
Fig. 3 shows a cross section through the housing wall
of a hearing device constructed by a
conventional method, with assembled seal.
Fig. 4 shows a diagrammatic cross section through a
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part of a hearing device housing, with an
acoustic lead mounted in accordance with the
invention andlor a receiving seat for a module.
Fig. 5 shows a diagrammatic cross section through a
housing wall portion with an operating unit and
with a through-opening and unit holder built on
in accordance with the invention.
Fig. 6 shows a diagrammatic representation of the
connection, according to the invention, of two
function units of a hearing device.
From the explanations given in the introductory part of
the description, it will already be apparent to the
skilled person that, depending on the hearing device to
be designed and on its structure, there are a large
number of possible ways, in combined processing in two-
component or multi-compnent injection-molding methods,
in particular overmolding, of producing two or more of
the required structural parts in a space-saving manner,
and then of assembling them as one integral part.
Nevertheless, preferred ways of using said injection-
molding method are discussed below on the basis of a
number of illustrative examples. The actual technique
of two-component or multi-component injection-molding
is not discussed since, as has been mentioned, this is
already sufficiently known from general component
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construction, in particular from plastic pressure-
molding and injection-molding technology.
Fig. 1 is a diagrammatic and perspective view of the
shell 1 of a hearing device housing, for example of a
hearing device worn outside the ear. Along its front
faces 3, it is to be assembled to further housing parts
so that its interior is tightly sealed off along these
front faces 3. This is customarily achieved by the fact
that, as is shown in Figure 3, positioning and
retaining devices are incorporated in the area of the
front faces 3, for example grooves are incorporated
into the wall of the housing portion 1, into which
grooves a seal 7 is then mounted manually.
According to the invention, a seal 7a is now injected
directly onto said housing shell 1 or the front face 3
by two-component overmolding/injection-molding. The
material of the actual wall of the housing part is
sufficient to satisfy the requirements in respect of
the stability of the housing, etc., while the material
of the second component injected on in the overmolding
method satisfies the requirements imposed on the seal
7a. The sealing portion 7a can in this case be exactly
dimensioned to comply with the sealing requirements,
and, likewise, the wall of the housing portion 1 can be
dimensioned and shaped exclusively on the basis of the
criteria to be placed on the housing. A design of the
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housing wall which additionally satisfies the
assembling of a separate seal 7, according to Fig. 3,
no longer applies.
Fig. 4 is a diagrammatic representation showing how,
for example, an acoustic lead 13 is built onto one end
of a hearing device housing 10 in the manner according
to the invention, for example at the output of an
electro-mechanical transducer mounted in the hearing
device, or, in analogy, at the input of an acoustic-
electric transducer (not shown) provided on the hearing
device. In addition, an elastic and resilient receiving
block 15 can be integrated in the housing 10 for the
transducer unit 12. Housing 10 and acoustic lead 13
and/or housing 10 and receiving block 15, or all three,
housing 10, receiving block 15 and acoustic lead 13,
are produced as one part in a two-component or three-
component injection-molding method. Here, the material
usually chosen for the housing 10 or its wall is a
material which satisfies the requirements to be placed
on the housing, the material chosen for the acoustic
lead 13 is, for example, a material which is
biocompatible, as for example for a hearing device worn
outside the ear, and the material chosen for the
receiving block 15 is a material which satisfies the
requirements in respect of impact and shock absorption
and mounting of the transducer 12. It is also readily
possible, for example, to choose an electrically
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conductive material for the block 15, if for example
the transducer 12 is to be electrically screened.
Fig. 5 shows, once again diagrammatically, a first
part, for example once again a wall of a housing
portion 10, with a through-opening 17 via which there
protrudes an operating member 19, such as a switch
[lacuna] an operating element 25 of the hearing device.
By virtue of the fact that, in the two-component or
multi-component injection-molding together with the
housing part 10, elastic and optionally sealing
portions 21 are injected in the area around the
through-opening 17 for the operating member 19, and
also, if appropriate, a receiving seat 23 for
resilient, tight fixing of the unit 25, an optimum
space-saving installation of the unit 25 is permitted.
Fig. 6 shows how, on the housing 30 of a unit 34, for
example an electronics module of the hearing device, a
receiving seat 32 is built on for corresponding
positioning and holding of a further unit 34 using said
two-component or multi-component injection-molding
method, by which means once again an optimum small-size
assembly with high packing density is permitted.
By virtue of the production method according to the
invention, considerable economies are achieved during
assembly. Assembly steps are eliminated by the integral
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two-component or multi-component production. Moreover,
an extremely important advantage pertaining to hearing
devices is achieved, namely that functionally different
parts, which come to lie on one another anyway after
assembly, can be specifically configured with the
respectively required material properties, but
nonetheless as one integral part. Measures for long-
lasting assembly of these parts, which measures take up
structural volume, are thus dispensed with. If we take
as an example the embodiment shown in Figures 1 through
3, it is evident that a seal 7a, which only has to
satisfy the exact sealing requirements, can be made
substantially smaller and thinner, if it is formed
integrally on the part 1, than is the case if it has to
be produced separately as seal 7 and then fitted, for
example manually, onto the corresponding front faces of
the part 1, either by adhesion, engagement, or the
like. The precision with which the sealing part 7a can
be built directly onto the wall of the part 1 forming
the front face 3 is, with the same dimex~sions,
virtually impossible, or possible only with great
effort, by assembly of separate parts.
