WO2010023331A2

WO2010023331A2 - Tube for sound transmission

Info

Publication number: WO2010023331A2
Application number: PCT/EP2009/067688
Authority: WO
Inventors: Erdal Karamuk; Albora De Pablo Pena; Hans Georg Meier
Original assignee: Phonak Ag
Priority date: 2009-12-21
Filing date: 2009-12-21
Publication date: 2010-03-04
Also published as: WO2010023331A3

Abstract

A device for the acoustic connection of a hearing device to a ear mould or for the acoustic coupling of a hearing device respectively comprises a tube (1) with at least two segments (3, 5). The at least two segments do have different mechanical properties and/or are designed such that they are formed within at least almost one plane.

Description

Tube for sound transmission

The present invention refers to a device for the acoustic connection of a hearing instrument to an ear mould or an earpiece according to the preamble of claim 1 as well as a method for the production of the device.

For the acoustic coupling of hearing devices preformed sound tubes, so-called "micro-tubes" are well known. These are polymer tubes with integrated connecting parts for the coupling to a hearing instrument at one end and with a connection to an ear fitting part or ear mould at the other end. A typical example of such a connecting tube comprises an already thermically preformed sound tube with arranged at one end a so-called hook adapter and at the other end an ear fitting piece or ear mould. Such a sound tube has two essential functions:

1. It is fixing and positioning via the preformed tube portion the hearing instrument behind the ear, and

2. it transmits the sound into the auditory canal and guarantees that the ear fitting piece is well fitted at the ear entrance.

To achieve a good adaptation to the anatomy of the user different lengths are offered to the acoustician or distributor, preformed for the left ear as well as for the right ear. This means as a consequence great logistic and material investment for the acoustician as well as for the producer which is combined with high costs. At actual solutions e.g. eight or more different tubes in different lengths are offered, four tubes each for the left as well as for the right ear.

As a result, in particular the adaptation of hearing instruments outside the well known distribution channels is difficult:

- for so-called low-cost products, as here a great pressure exists on the production costs and the margins are comparatively low, and as a consequence every additional non-used part has a negative influence,

- at products for so-called "emerging markets" as no comparable infrastructure with acousticians having a respective education is available, and

- at products, which are sold via alternative distribution channels like e.g. internet, supermarket, drugstores and which are adapted by the consumer himself or via the internet. In this case it is not desirable to add a plurality of parts for the acoustic coupling, first of all due to cost reasons, but also for not making the handling additionally more complicated.

For such applications it is desired to have an inexpensive, universal acoustic coupling without individual adaptation and with minimal logistic expenses. In the state of the art such as the US 6 275 596 or the US 2005/0190939 solutions are known where a pre-bent tube system is described for the acoustic coupling. In other words, the described tubes which are preformed consist out of a sole material.

In the US 25 73 132, the US 43 81 830, the EP 17 55 361, the US 600 91 83 and the US 59 75 235 solutions are proposed with several parts, where either for the left or the right adaptation different geometries are proposed or several parts have to be combined or assembled respectively to achieve on one side an individual adaptation to the ear and on the other side to take the difference between right and left into consideration. Also the EP 1 800 516 Bl shows a possibility how the logistics at pre-bent sound tubes can be reduced, as for different hearing instrument types respective adapters are provided which all are compatible with a universal sound tube system. However, the further reduction of the amount of sound tubes within one set is not taken into consideration.

One object of the present invention consists in particular to take the above mentioned requirements into consideration by means of one preferably one-piece tube system. Thereby, at a universal acoustic coupling the following factors should be taken into consideration:

Regarding cosmetics:

- Minimal visibility as in state-of-the-art systems

- No visible portions like couplings or intersections of various tube portions

Regarding comfort:

- Maximal wearing comfort is an important factor, no pressure should be transferred to the skin and no - A -

pressure marks should occur, as often occurring at connections of various tubes.

- A secure positioning of the hearing instrument at the ear is important. As on one side the hearing instrument should be unremarkable and unnoticeable (forgotten by the user...) its position should be secured such that an unnoticed loss of the device is practically impossible.

- The quality of the usability and handling should not be limited. Today's systems with pre-bent tubes are very simple in handling and certainly represent the level in respect to user-friendliness.

Regarding quality:

- The biocompatibility according to ISO 10993 has to be guaranteed. Therefore, if possible known materials should be used to avoid expensive development and tests .

- Reliability has to be guaranteed. The environmental resistance of the system against perspiration, sebum, cerumen, UV, cosmetics, solvents and cleaning means define the durability of the product.

- The production costs should not be essentially higher than at today's systems, as it is a disposable article which is replaced after some weeks of use. According to the present invention a device is proposed according to the wording of claim 1. The device as proposed, which means the tube for the acoustic connection of a hearing instrument to an ear fitting part or ear mould respectively for the acoustic coupling of the hearing instrument, comprises at least two continuously connected portions or segments with different mechanical properties or different material features respectively and/or which are arranged within the same plane. The two segments or portions comprising e.g. different hardness and/or different flexibility and/or each comprising a bending, which both are formed within the same plane.

The present invention describes therefore a tube system, which can be used universally, which means which does not know the differentiation between left and right and also ^'can be adapted more easily in relation to its length. The background of the invention consists in providing a plurality of portions or segments e.g. based on at least two different materials with different mechanical properties for the tubing system, the segments or portions are connected irreversible. E.g. it is also proposed to use a hard tube such as e.g. with a Shore hardness between e.g. 55⁰D to 72°D for the upper end. This enables to integrate a firm bending, which as known is responsible for the hold and the positioning of the hearing instrument. Following to this rather hard tube a further portion follows with a Shore D hardness of e.g. 25° - 40°, which ends with a slightly L-formed bending. This tube portion is due to its low E-modulus very torsion soft, which means that it can be drawn either to the left side or to the right side without the transfer of great forces to the hard tube portion and the hearing instrument. Using the same approach, one can also imagine the opposite way of having a firm tube segment that allows easy insertion into the ear which is coupled to a softer segment, that absorbs the torsional moment and allows a smooth fit to the contour of the outer ear.

According to a further embodiment the sound tube may consist out of three segments: a rather hard upper part, of which the bending guarantees the firm positioning at the ear, a middle soft part, which is not or only insignificantly bent and a further hard part, which is introduced into the ear canal and which due to its higher stiffness comprises an easy handling. Again according to a further embodiment a tube system is proposed comprising at least two bendings within the same bending direction, the two bendings are shaped more or less within the same plane.

The invention shall be described with reference to the examples as shown within the attached figures. In the figures:

Fig. 1 shows a pre-bent sound tube for the connection of a hearing aid with an ear piece that corresponds to the prior art,

Fig. 2 shows in a longitudinal cut the tube system according to the present invention with connected segments of different hardness and integrated coupling parts for the hearing instrument and the ear fitting part,

Fig. 3 shows schematically in sectional cut the intersection between the two tube segments, Fig. 4 shows in a schematic illustration a hearing instrument with a sound tube, which is essentially symmetrical, Fig. 5 shows in a schematic illustration a hearing instrument with a sound tube which is essentially symmetrical, which is combined out of three segments and which is pre-bent within a single plane, and Fig. 6 shows schematically a possible production process for the irreversible connection of various tube segments to form a sound tube.

Fig. 1 shows a pre-bent sound tube for a left ear with integrated connectors on each side for the hearing aid and the earpiece that corresponds to the prior art. It is clearly visible, that the tube is bent in two planes.

Fig. 2 shows schematically in a longitudinal cut a tube system 1 according to the present invention with connected segments 3 and 5 of different hardness. At one end the tube is connected with an integrated coupling part 11 for the hearing instrument and at the other end with a coupling part 13 for the ear fitting piece.

The intersection 7 between the two tube segments 3 and 5 is shown in enlarged view as a cut in fig. 3. The hard tube 3 is connected seamless with the soft tube 5. In case of e.g. a welded joint a mixing zone 21 occurs, in which the two materials are melted into each other.

Fig. 4 shows schematically a hearing instrument 31 with an essentially symmetrical sound tube 1. Within the hard segment 3, which through the coupling part 11 is connected with the hearing instrument 31, there is a first bending 4, which guarantees the fit at the ear and the positioning behind the ear (microphone position) . A second L-shaped bending 6 within the soft tube segment 5 facilitates the introduction of the ear fitting piece 32 into the ear canal. Both bendings 4 and 6 are shaped within the same plane. The ear fitting piece 32 can be drawn to the left as well as to the right. The torsion forces are absorbed by the soft tube 5 in the section above the bending 6.

The tube system according to the present invention as shown in fig. 5 comprises the following features: The at least three tube segments 41, 43, 45 with different hardness do have e.g. identical interior and exterior diameters and are soldered flush into each other. The segments 41 and 45 near the hearing instrument 31 or the ear fitting piece 32 respectively may have the same hardness as e.g. Shore D 50°-70°, while the middle part 43 can be more flexible having a Shore D hardness of e.g. 25°- 40°. It would be an advantage to use the same base material with only different modulus or hardness of the various segments . An example for an embodiment could be the use of a thermoplastic elastomer polymer such as PEBAX

(Polyetherblockamide) which is available in different hardness from 25°C up to 75°D. The various tube segments can be adhered or they can be connected e.g. by using a laser or a thermic soldering device. Similar connections are already used at catheters or for cardiovascular interventions. Processes for such solderings are therefore best known out of the state of the art and the respective technologies are available. However, the middle part 43 can have the same hardness as the parts 41 and 45. In such a case it is preferred if the bendings between the parts are shaped within the same plane.

For the better understanding and by way of an example a possible production process is described with reference to fig. 6, which enables to combine several tube segments having the same geometry and different hardness, where λgeometry' refers to identical inner and outer diameters of the tubes, while the length of each tube segment can be different, depending on the design and the application. For that purpose the pre-cut tube segments 3 and 5 are fitted on a support wire 51, the outer diameter of which corresponds to the interior diameter of the tube. This support wire may be coated e.g. with Teflon or another fluorpolymer, to prevent the adherence of the welded tube and to simplify the removal of the tube. Over the tube segments 3 and 5 further a so-called heat-shrinkable tube 53 is attached, which in its unprocessed conditions does have a slightly larger interior diameter compared to the tube segments. The required heat for the welding process is applied over the shrink tube, which at the same time is fixing the two tube segments. A welding equipment which enables such kind of processes is offered e.g. by the company BW-Tech (Bϋlach, Switzerland) . After finishing the welding process the heat-shrink tube is removed and the connected tube segments are detached from the supporting wire. Such process can of course be automated by supplying the parts to a welding equipment, individually or using interchangeable carrier cassettes that would allow a parallel welding of three or more tubes simultaneously.. On the two tube segments finally the mentioned coupling elements are integrated. On the end towards the hearing device the respective thread or plug-in connection is arranged and towards the ear canal end the respective element to fix an ear fitting piece. These coupling elements may be identical to the other parts currently used in prior art tubes.

Alternatively one can also imagine a manufacturing process where - as a precursor product - a straight tube of a hard material is initially manufactured, cut to a desired size and overmolded with the coupling elements. This precursor tube is than cut at a specified location and a defined segment of softer tubing is added in between using e.g. a process as described above. This approach is suited well for a combination of hard/soft/hard segments, where the hard segments at the ear and hearing aid side have the same stiffness. Additionally this process flow allows to easily manufacture hard/soft/hard tubes of different lengths by using only one precursor tube and introducing soft elements of different lengths.

The bendings at the tube system can be designed such that they are all arranged within the same plane. Thereby, the right/left symmetry is guaranteed, as the segment carrying the earpiece can be either twisted by ~90° to the left or right side for introduction into the respective ear.

A further improvement compared with the prior art is the introduction of bendings within only one plane, which comprise the same bending direction. The bending line of the sound tube within the plane does not have any direction changes or inflection points respectively. This is shown with the example in fig. 5.

The advantage of arranging such bendings consists in the improvement of the mechanical fitting at the ear. When the lower part with the ear fitting piece is bent to be inserted into the ear canal the torsion moment, which may occur due to a certain stiffness, urges the hearing device towards the head, which is connected to the upper end of the sound tube. Therefore, always a slight contact pressure is remaining, which improves in addition the fitting without being uncomfortable. In addition, a cosmetic perfect fitting is guaranteed, as the hearing device cannot protrude and as a result is not unnecessarily highly visible. Of course it is also possible to use instead of the mentioned elastomeric PEBAX other elastomeric polymers such as in particular so-called blockcopolymers and/or combinations of different elastomeric polymers, which can be easily welded to each other. Referring to the above mentioned points the proposed system does have the following advantages and solutions:

Cosmetics :

- By the seamless connection of the two tube segments with different hardness occurs a non-visible intersection. As for the two segments the same base material with different hardness is used there are also no differences in color or transparency. - By connecting tube segments with the same diameter it is prevented that a visible intersection occurs, which can be arranged at a well visible position directly above the tragus. Comfort :

- By the seamless connection there are no pressure sections present, which would occur at hinges or at the interconnection of discrete segments.

- By using a soft tube segment at the lower part the two functions "securing positioning" and "sound transmission" can be uncoupled in an optimal way. It is prevented that in case of a non-ideal length the upper bending is responsible that the ear fitting piece will be removed from the ear canal. Quality:

- The proposed solution corresponds in its construction and design to the today's "fit&go" solution and can be applied in an identical way.

- By the reduction to a sole bending fixture (possibly with different lengths) within one plane the bending process can be simplified and a more consistent quality can be guaranteed.

- By using known technologies for the welding of the tubes the costs of one individual tubing system can be kept relatively low.

Further advantages of the inventively proposed acoustic coupling system are e.g. the reduction of costs and the simplification of the logistic complexity. Furthermore, a cosmetically superior and comfortable solution for an application is possible at which the consulting effort of the acoustician can be reduced or can be omitted completely, as with the proposed product a reduced amount of tubing systems can be delivered together with the hearing device. Furthermore to be mentioned is the reduction of the variety (left/right) and as a consequence also the production costs can be reduced as at least half of the parts can be omitted. Additional cost reduction can be achieved by a lower amount of required processing means.

As it is well known, the softer grades of a thermoplastic elastomer have usually lower environmental stability e.g. against UV radiation compared to the harder grades. This can be overcome by adding stabilizing agents in the resin. Alternatively, one can also imagine to protect the complete tubing system with a very thin conformal barrier coating. Such a coating could have a thickness of less than 200 nanometers and would therefore not be visible. It would allow to protect or shield the soft segment and the welded transition region against environmental impacts by e.g. UV radiation or acidic and oily substances form sweat, cosmetics, sun lotion or cleaning agents. Coating technologies such a chemical vapor deposition (CVD) or molecular vapor deposition (MVD) or plasma-enhanced-CVD are established and well known for such an application.

The above mentioned inventive tube systems and in particular those mentioned within the figures 1 - 5 are of course only examples which can be changed in any manner, modified and amended by further elements. In particular, it is also possible to use instead of the proposed two segments three or even four parts, to take the individual requirements into consideration.

Alternatively, one can also imagine to combine tubing segments with the same outer diameter but different inner diameters to have a ^λstepped' tubing with increasing inner diameters from the receiver side in the hearing instrument to the earpiece segment, leading to an improved acoustic coupling with additional resonances (horn effect) . The tube segments of varying inner diameter could have identical or different material properties.

Also the materials are not restricted to the above mentioned materials, but all in particular within the medicine technique used polymer materials such as in particular elastomeric materials which are available with different hardness are suitable for the production of the inventively proposed tubing systems.

Claims

Claims :

1. Device for the acoustic coupling of a hearing device to an ear mould or for the acoustic coupling of a hearing device respectively, characterized by a tube (1) with at least two segments (3, 5) which have different mechanical properties and/or which both are formed at least nearly within one plane.

2. Device according to claim 1, characterized in that the segments are connected continuously to each other.

3. Device according to claim 1 or 2, characterized in that the at least two segments or tube segments (3, 5) do have different hardness and/or different flexural and/or torsional stiffness.

4. Device according to one of the claims 1 to 3, characterized in that the at least two segments or tube sections (3, 5) are consisting of the same polymeric material, the segments or sections have different hardness and/or different flexural and/or torsional stiffness.

5. Device according to one of the claims 1 to 3, characterized in that the at least two segments or sections comprise different polymer materials, which are weldable with each others .

6. Device according to one of the claims 1 to 5, characterized in that the segments or tube sections are consisting out of at least one elastomeric material such as in particular a thermoplastic elastomer.

7. Device according to one of the claims 1 to 6, characterized in that the segments or tube sections consist out of at least one polyetherblockamide (PEBAX) .

8. Device according to one of the claims 1 to 7, characterized in that at least one of the segments, such as preferably the one near the hearing device, does have a higher hardness as the one or the other remaining segments, whereby preferably the one near the ear fitting piece or mould is softer or more flexible.

9. Device according to one of the claims 1 to 7, characterized in that at least one of the segments, such as preferably the one near the hearing device, does have a lower hardness as the one or the other remaining segments, whereby preferably the one near the ear fitting piece or mould is harder or less flexible.

10. Device according to one of the claims 1 to 9, characterized in that at least three segments (41, 43, 45) are provided.

11. Device according to one of the claims 1 to 10, characterized in that the tubing system at the end directed towards the hearing device is integrally connected with a coupling part (11) for the hearing device and at the opposing end with a coupling part (13) for the ear piece element (33) .

12. Device according to one of the claims 1 to 11, characterized in that segment near the hearing device does have a Shore hardness > 50⁰D, preferably > 65°D an near the ear piece element a Shore hardness < 50⁰D, preferably in the range of 25°D - 40°D.

13. Device according to one of the claims 1 to 7 and 10 to 12, characterized in that each of the segments (41, 45) near the hearing device and near the ear piece element does have a Shore hardness > 50⁰D, preferably > 65°D and the one (43) in between a hardness of < 50⁰D, preferably in the range of 25°D to 40⁰D.

14. Device according to one of the claims 1 to 13, characterized in that the device is pre-bent and each segment does have at least one bent section.

15. Device according to one of the claims 1 to 14, characterized in that the bendings are formed within the same plane.

16. Device according to claim 15, characterized in that each bending within the plane does have a constant bending direction.

17. Device according to claim 16, characterized in that the hearing device at the insertion of the ear fitting piece into the ear canal is slightly pressed towards the head due to the torsional moment as a result of the stiffness of the tube.

18. Process for the production of a device according to one of the claims 1 to 17, characterized in that the at least two tube segments (3, 5, 41, 43, 45) are interconnected by means of welding, as in particular by means of laser welding or thermo-welding.

19. Process for the production of a device according to one of the claims 1 to 17, characterized in that connecting the at least two tube segments is achieved by means of adherence technique, e.g. by using an additional hot melt adhesive in the area of the connection.

20. Process according to one of the claims 18 or 19, characterized in that the at least two precut tube segments (3, 5) are arranged on a support wire (51) of which the outer diameter corresponds to the interior diameter of the two tube segments, a heat shrinking tube (53) is further attached over the tube segments, which unprocessed does have a larger interior diameter than the outer diameter of the tube segments, the required heat for the welding is further added over the heat shrinking tube, which at the same time is fixing the two tube segments against each other and exerting axial pressure.