Patent Description:
A hearing instrument comprises a sound exit to deliver sound into a user's ear canal. The sound exit is one of the most vulnerable parts of a hearing instrument as it is prone to ingression of ear wax, sweat, and dander.

Wax guard systems for hearing instruments are designed to either inhibit ingressions of ear wax (cerumen), sweat, humidity and other particles into a sound tube or loudspeaker (also referred to as the receiver) of a hearing instrument with a filter or to lead the sound from the loudspeaker around a cap which serves as wax protection.

The filters of systems known in the art have to be exchanged with new ones regularly, the frequency of the exchange depending on the amount of ingressions. Users with reduced dexterity such as elderly people which are typical users of hearing instruments may be challenged by having to handle small items such as filters for hearing instruments. Moreover, new filters need to be purchased resulting in costs.

Systems with a cap leading the sound around this cap distort the straight sound flow. Also, due to the cap being attached on top of the device, there is a risk for the cap to fall off into the ear canal, causing risks for the user of the hearing instrument.

<CIT> describes a hearing aid which has a cerumen guard comprised of a rigid porous plastic plug adjacent to the exterior surface of the hearing aid shell. The cerumen guards may be inserted into the receiver outlet, the microphone inlet, or the vents of the hearing aid. The rigid porous plastic has a hydrophobic characteristic, a multiplicity of interconnected pores effectively avoids the accumulation and clogging of inlets, outlets, and vents by cerumen while allowing transmission of sound. Use of sintered plastic beads provide for the rigidity of the porous plastic plug.

It is an object of the present invention to provide a novel filter solution for a hearing instrument.

The object is achieved by a hearing instrument according to claim <NUM>.

Preferred embodiments of the invention are given in the dependent claims.

The term medial as used herein refers to a direction and parts of a hearing instrument closer to the center of a user's body when the hearing instrument is at least partially inserted into a user's ear canal, while the term lateral refers to the opposite direction.

According to the invention, a hearing instrument comprises a shell configured to be at least partially inserted into a human ear canal, and a sound tube arranged in the shell, configured to guide sound emitted by a receiver or loudspeaker, wherein a filter insert is arranged to cover a sound outlet opening of the sound tube and held against the sound outlet opening by at least one elastic element attached to the shell allowing the filter insert to be pulled away from the shell. The filter insert is thus pulled against the sound outlet opening by the elastic element, e.g. to reposition the filter insert after cleaning.

According to the invention, the elastic element is a tension spring or an elastic cord.

In an exemplary embodiment, the sound tube ends in a hole in the shell, wherein the hole in the shell is configured as a bushing or has a bushing arranged therein, wherein the elastic element is attached to the bushing.

In an exemplary embodiment, the bushing comprises a medial opening and a lateral bottom with an opening toward the sound tube, wherein the filter insert is arranged in the bushing.

The tension spring may be arranged in the bushing, wherein a lateral end of the tension spring is fixed to the bushing and a medial end of the tension spring is fixed to the filter insert.

In an exemplary embodiment, the bushing has an outer wall and an inner wall.

In an exemplary embodiment, the tension spring is arranged in a space between the inner wall and the outer wall of the bushing. This may help protect the tension spring from being distained by ingressions.

In an exemplary embodiment, one, two, three, four or more security threads are provided to connect the filter insert to the shell or bushing to limit the movement of the filter insert away from the shell. This allows for preventing the filter insert to fall off the hearing instrument into the ear canal. If the at least one elastic element is at least one elastic cord, it may also assume the function of a security thread so separate security threads are not required. The elastic cord may be configured to be elastic until reaching a certain extension and be considerably less elastic beyond this point. This may for example be achieved by a configuration of a fabric of the cord arranged around an elastic core.

In an exemplary embodiment, the elastic element has a retraction force smaller than a weight of the hearing instrument when the filter insert is pulled away from the shell, so that just by holding the hearing instrument, e.g. by a handling knob, the filter insert will remain outside of the bushing or hole.

In an exemplary embodiment, the bushing is glued and/or press-fitted to the shell and/or the sound tube is glued and/or press-fitted to the bottom of the bushing.

In an exemplary embodiment, the filter insert comprises a series of two or more concentric discs, connected to each other through a hub, wherein each disc is provided with a multitude of through-holes. The discs may be arranged at a distance between each other. When the filter insert is removed from the hearing instrument, it may easily be cleaned from any ingressions brushing the spaces between the discs or using an air jet. The hub may be arranged about a longitudinal axis of the filter insert and the discs may protrude radially from the central axis beyond the hub.

In an exemplary embodiment, the through-holes of each disc are non-overlapping or misaligned with the through-holes of one or more adjacent discs or all of the other discs, thus creating a wax labyrinth.

In an exemplary embodiment, the discs comprise a top disc at a medial end of the filter insert, wherein the top disc has a diameter greater than the diameters of the other discs. This allows for inserting the other discs into a hole in the hearing instrument while the top disc may cover said hole.

In an exemplary embodiment, the filter insert further comprises a handling knob arranged at the medial end of the hub or of the top disc to facilitate pulling the filter insert out of the hole in the hearing instrument.

In an exemplary embodiment, the diameter of the other discs corresponds to an inner diameter of the bushing or the inner wall thereof.

In an exemplary embodiment, the diameter of the top disc is greater than the diameter of the bushing or the inner wall thereof, in particular as great as or greater than the diameter of the outer wall thereof.

In an exemplary embodiment, the filter insert comprises or consists of or is coated with a repellent material, in particular PTFE to facilitate cleaning.

In an exemplary embodiment, the filter insert may be produced by 3D printing.

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, and wherein:.

Corresponding parts are marked with the same reference symbols in both figures.

Hearing instruments or parts thereof (e.g. shells or molds) configured to be placed at least partially into a human ear canal are subject to ingression of organic material existing in or produced by the ear canal or its tissue or glands, like cerumen (ear wax), sweat, and dander.

The present invention provides a solution aiming at protecting the sound flow from hearing instruments towards the human ear drum (tympanic membrane) against the ingression of any solid, plastic or fluid substances.

<FIG> is a schematic detail view of a hearing instrument <NUM> comprising a shell <NUM> or mold configured to be at least partially inserted into a human ear canal and a sound tube <NUM> arranged in the shell <NUM>, ending in a hole therein and configured to guide sound emitted by a receiver <NUM> or loudspeaker, which may also be arranged in the shell <NUM>. In other embodiments, the receiver <NUM> may be located in an external device such as a behind-the-ear part of a hearing instrument <NUM>, connected through a sound guide such as a tube or hose to the sound tube <NUM> in the shell <NUM>.

The hole in the shell <NUM> may be configured as a bushing <NUM> or have a bushing <NUM> arranged therein. The bushing <NUM> may have an outer wall <NUM> and an inner wall <NUM> and a bottom <NUM> with an opening to allow sound from the sound tube <NUM> to enter. The bushing <NUM> may be glued and/or press-fitted to the shell <NUM>, while the sound tube <NUM> may be fixed, e.g. glued and/or press-fitted, to the bottom <NUM> of the bushing <NUM>.

A filter insert <NUM> is configured to be at least partially inserted into the bushing <NUM>, in particular within the inner wall <NUM> thereof. The filter insert <NUM> comprises a series of concentric discs <NUM>, <NUM>, <NUM>, connected to each other through a hub <NUM>. The illustrated embodiment shows three discs <NUM>, <NUM>, <NUM>. However, the skilled person readily understands that there may be more or less than three discs <NUM>, <NUM>, <NUM> in the filter insert <NUM>. Each disc <NUM>, <NUM>, <NUM> is provided with a multitude of through-holes <NUM> to allow the sound to pass through. In an exemplary embodiment, the through-holes <NUM> of each disc <NUM>, <NUM>, <NUM> are non-overlapping or misaligned with the through-holes <NUM> of one or more adjacent discs <NUM>, <NUM>, <NUM> or all other discs <NUM>, <NUM>, <NUM> thus creating a wax labyrinth. The discs <NUM>, <NUM>, <NUM> comprise a top disc <NUM> at or near a medial end of the filter insert <NUM>, wherein the top disc <NUM> has a diameter greater than the diameters of the other discs <NUM>, <NUM>. The diameter of the other discs <NUM>, <NUM> may correspond to an inner diameter of the bushing <NUM> or the inner wall <NUM> thereof, in particular the diameter of the other discs <NUM>, <NUM> may be nearly the same as the inner diameter of the bushing <NUM> or the inner wall <NUM> thereof such that the other discs <NUM>, <NUM> may enter the bushing <NUM> easily. The diameter of the top disc <NUM> is for example greater than the diameter of the bushing <NUM> or the inner wall <NUM> thereof, in particular as great as or greater, e.g. slightly greater, than the diameter of the outer wall <NUM> thereof, so that the top disc <NUM> can cover a medial opening of the bushing <NUM>, in particular completely.

One, two, three, four or more security threads <NUM> may be provided to connect the filter insert <NUM>, in particular a lateral end thereof, to the bushing <NUM>, in particular the bottom <NUM> thereof, to limit the movement of the filter insert <NUM> out of the bushing <NUM>.

A tension spring <NUM> or another elastic component, e.g. an elastic cord, may be arranged in the bushing <NUM>, e.g. in a space between the inner wall <NUM> and the outer wall <NUM> of the bushing <NUM>, wherein a lateral end of the tension spring <NUM> is fixed to the bushing <NUM>, e.g. the bottom <NUM> thereof, and a medial end of the tension spring <NUM> is fixed to the filter insert <NUM>, in particular the top disc <NUM> thereof. The filter insert <NUM> is thus pulled into the bushing <NUM> by the tension spring <NUM>, e.g. to reposition the filter insert <NUM> after cleaning.

The filter insert <NUM> further may comprise a handling knob <NUM> arranged at the medial end of the hub <NUM> or of the top disc <NUM>, allowing the filter insert <NUM> to be grabbed by a user and pulled out of the bushing <NUM>, e.g. for cleaning the filter insert <NUM>.

<FIG> is a schematic view of the hearing instrument <NUM> with the filter insert <NUM> being pulled out of the bushing <NUM>.

The extension of the filter insert <NUM> from the bushing <NUM> may be limited by the security threads <NUM>. Pulling the filter insert <NUM> out of the bushing <NUM> will tension the tension spring <NUM>. The safety threads <NUM> will also protect the tension spring <NUM> from overextension.

In an exemplary embodiment, the tension spring <NUM> is dimensioned with a retraction force smaller than the weight of the hearing instrument <NUM> when the filter insert is pulled away from the shell, so that just by holding the hearing instrument <NUM> by the handling knob <NUM>, the filter insert <NUM> will remain outside of the bushing <NUM>. This allows for a reliable cleaning of the filter insert <NUM>, e.g. using a brush or an air jet.

Releasing the handling knob <NUM> will allow the filter insert <NUM> to be pulled back into the bushing <NUM> by the force of the tension spring <NUM>.

The combination of multiple stacked discs <NUM> to <NUM> with through-holes <NUM> provides a stack of filters which will prevent the receiver <NUM> and/or the sound tube <NUM> from being occluded and damaged by particle ingression.

The described solution allows for quick cleaning which eliminates the requirement for frequent filter replacement. This results in an easier handling of hearing instruments <NUM> worn in the ear and also in a cost reduction for the user of the hearing instrument <NUM>.

The filter insert <NUM> may for example be produced by 3D printing.

The filter insert <NUM> may comprise or consist of or be coated with a repellent material such as PTFE.

Claim 1:
A hearing instrument (<NUM>), comprising a shell (<NUM>) configured to be at least partially inserted into a human ear canal, and a sound tube (<NUM>) arranged in the shell (<NUM>), configured to guide sound emitted by a receiver (<NUM>) or loudspeaker, wherein a filter insert (<NUM>) is arranged to cover a sound outlet opening of the sound tube (<NUM>) and is held against the sound outlet opening by at least one elastic element attached to the shell (<NUM>) allowing the filter insert (<NUM>) to be pulled away from the shell (<NUM>) against a retraction force of the elastic element, characterized in that the elastic element is a tension spring (<NUM>) or an elastic cord.