Patent Publication Number: US-8116496-B2

Title: Earpiece for a hearing device with bayonet fitting

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of German application No. 10 2007 023 055.0 DE filed May 16, 2007, which is incorporated by reference herein in its entirety. 
     FIELD OF INVENTION 
     The present invention relates to an earpiece for a hearing device, said earpiece being wearable in the ear canal and comprising a receiver including a receiver connecting piece at the sound outlet and an ear shell in which the receiver is fixed and which holds the receiver in the ear canal and which possesses, when worn in the ear canal, an inner side facing the eardrum and an opposite outer side on which the receiver is detachably fixed. The term “hearing device” is understood here as meaning in particular any ear-wearable device such as a hearing aid, earphones, headset, or the like. 
     BACKGROUND OF INVENTION 
     Hearing aids are portable hearing instruments which serve to provide hearing assistance to the hearing-impaired. In order to accommodate the multiplicity of individual requirements, different designs of hearing aid are provided, including behind-the-ear (BTE) and in-the-ear (ITE) hearing aids, e.g. concha or completely-in-canal (CIC) instruments. The hearing devices cited by way of example are worn on the outer ear or in the auditory canal. However, bone conduction hearing aids, implantable or vibrotactile hearing aids are also commercially available. In these cases the damaged hearing is stimulated either mechanically or electrically. 
     The basic components of a hearing aid are essentially an input transducer, an amplifier and an output transducer. The input transducer is generally a sound pickup device, e.g. a microphone, and/or an electromagnetic pickup such as an induction coil. The output transducer is mainly implemented as an electroacoustic transducer, e.g. a miniature loudspeaker, or as an electromechanical transducer such as a bone conduction receiver. The amplifier is usually incorporated in a signal processing unit. 
     This basic design is shown in  FIG. 1  using the example of a behind-the-ear hearing aid. Installed in a hearing aid housing  1  for wearing behind the ear are one or more microphones  2  for picking up sound from the environment. A signal processing unit  3  which is likewise incorporated in the hearing aid housing  1  processes the microphone signals and amplifies them. The output signal of the signal processing unit  3  is transmitted to a loudspeaker or receiver  4  which outputs an audible signal. The sound is in some cases transmitted to the wearer&#39;s eardrum via a sound tube which is fixed in the auditory canal using an earmold. The hearing aid and in particular the signal processing unit  3  are powered by a battery  5  which is likewise incorporated in the hearing aid housing  1 . 
     Also specifically known are receiver-in-canal (RIC) instruments which have a receiver unit for insertion into the auditory canal. These are fitted using not only so-called standardized soft ear tips but also using custom-made ear shells, i.e. earmolds, the receivers being inserted into the standardized or custom ear shell. When removing the receiver unit from the auditory canal, the user typically grips the receiver unit by the receiver or by the signal wire connected thereto. In the case of an earmold that is relatively firmly seated in the auditory canal, a high retaining force between the receiver and the earmold is necessary in order to prevent the entire unit from being pulled apart when the receiver unit is removed from the auditory canal. This high retaining force in turn means that the receiver unit can only be pushed out of the ear shell or more specifically earmold with the aid of a tool (“cherry stone remover”) for cleaning purposes and general replacement of the side facing the eardrum (inside of the ear shell). In this process the cerumen protection device disposed in the sound outlet opening is frequently destroyed. In addition, after many replacements both the receiver and the ear shell or more specifically a corresponding adapter become worn or damaged over time. This means that the seal tightness between the receiver and the ear shell is reduced, possibly resulting not only in soiling of the receiver but also in audible feedback. 
     The publication WO 2004/025990 A1 discloses a hearing aid with an external receiver module. The receiver module consists of an earmold to which a receiver is attached using a specially shaped fixing element which, on the one hand, holds the receiver and, on the other, is screwed to the earmold. 
     In addition, the publication DE 10 2004 016 577 A1 discloses a headset with hearing aid functionality. An earmold is connected to the headset module using a snap-in or bayonet fitting. 
     SUMMARY OF INVENTION 
     The object of the present invention is therefore to provide an earpiece for a hearing device and in particular a hearing aid in which the receiver is fixed in an ear shell with high retaining force on the one hand and in an easily exchangeable manner on the other. 
     This object is achieved according to the invention by an earpiece for a hearing device, said earpiece being wearable in the ear canal and comprising a receiver including a receiver connecting piece at the sound outlet and an ear shell in which the receiver is fixed and which holds the receiver in the ear canal and which possesses, when worn in the ear canal, an inner side facing the eardrum and an opposite outer side on which the receiver is detachably fixed, the receiver being attached to the ear shell by means of a bayonet fitting, and wherein a first part of the bayonet fitting is fixedly connected to the receiver connecting piece and a second part of the bayonet fitting is rotated from the inner side of the ear shell to the first part of the bayonet fitting. 
     The bayonet fitting ensures on the one hand a significantly higher retaining force than, for example, a detachable snap-in connection. On the other hand, no locking components are bent or strongly rubbed against one another when closing the bayonet fitting, resulting in little wear and tear. 
     In the ear shell there is preferably fixed an adapter in which the second part of the bayonet fitting is pivotally mounted. This means that the manner in which the receiver is fixed in the ear shell does not need to be specified already at the time of manufacture of the ear shell. 
     Another special variant of the earpiece according to the invention consists in that the second part of the bayonet fitting projects from the surface of the ear shell on its inner side, i.e. the side facing the eardrum when it is being worn, and possesses at least two surfaces which are parallel to one another and to the axis of the bayonet fitting. This makes it possible to open the bayonet fitting using a simple tool such as a small pair of pliers, without destroying any cerumen protection device located in the second part of the bayonet fitting. 
     In addition, the first part of the bayonet fitting can possess a conical section which is cut away accordingly on two opposite sides from the parallel surfaces of the second part of the bayonet fitting. The cone ensures that the receiver is seated in the ear shell coaxially to the sound channel of the ear shell or more specifically of the adapter and at the same time forms part of the bayonet fitting with the cut-away sides. 
     A seal can also be disposed between the first and second part of the bayonet fitting, thereby sealing it against dirt and interfering sound. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be explained in greater detail with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic sketch showing the design of a hearing aid according to the prior art; 
         FIG. 2  shows an earpiece with external receiver according to the present invention; 
         FIG. 3  shows a receiver connecting piece viewed from the sound output side of the receiver; 
         FIG. 4  shows a cross-section through the receiver connecting piece of  FIG. 3 ; 
         FIG. 5  shows the receiver connecting piece of  FIG. 4  rotated through 90°; 
         FIG. 6  shows an earmold adapter with receiver connecting piece in the unlocked state; 
         FIG. 7  shows the earmold adapter of  FIG. 6  on the sound output side; 
         FIG. 8  shows the earmold adapter of  FIG. 6  in the locked state; 
         FIG. 9  shows the earmold adapter of  FIG. 8  viewed from the sound output side. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     The examples described in greater detail below constitute preferred embodiments of the present invention. 
       FIG. 2  shows an external receiver unit for connection to a hearing aid main unit that is to be worn behind the ear. The external receiver unit has an earmold  10  in which an external receiver  11  is fixed. The fixing will be explained in more detail in connection with the further  FIGS. 3 to 9 . It is effected using an earmold adapter  12  and an acoustic seal  13 . The sound from the receiver  11  leaves the earmold  10  via a cerumen protection device  14 . The receiver  11  is supplied with electrical signals from the hearing aid main unit via a signal wire  15 . For this purpose the signal wire  15  is plugged into the hearing aid main unit by means of a connector  16 . The fixing of the receiver  11  in the earmold  10  should typically meet the following requirements: 
     1. “RETENTION”: The external receiver  11  shall be fixed in the earmold  10  such that it can be repeatedly detached. 
     2. “SEALING”: The external receiver  11  shall be protected against cerumen, dirt, sweat, etc. In addition, it shall be fixed in the earmold  10  in an acoustically sealed manner so that no sound becomes externally audible. 
     3. “VIBRATION DAMPING”: The vibrations of the receiver  11  relative to the earmold  10  shall be damped. This applies all the more to high-power receivers which make relatively large movements or rather natural oscillations. 
     4. “INCORPORATING RECEIVER PROTECTION”: At the same time the earmold adapter  12  advantageously also functions as a holder for a cerumen protection device. 
     The four requirements listed above are inventively fulfilled by an earmold adapter  12  with bayonet fitting. An earmold adapter  12  of this kind is shown in  FIGS. 6 to 9 . However, the first part of the bayonet fitting which is fixedly connected to the receiver connecting piece will first be explained with reference to  FIGS. 3 to 5 .  FIG. 3  shows said receiver connecting piece  20  from the sound output side.  FIGS. 4 and 5  show said receiver connecting piece  20  in cross-section, the sections being rotated through 90° relative to one another. The receiver connecting piece  20  essentially consists of a conical section  21  and a tubular section  22  adjoining the wide part of the cone. A sound channel  23  passes through the conical section  21  and the tubular section  22 . 
     The conical section  21  is cut away on two opposite sides parallel to the cone axis to produce two parallel lateral surfaces  24  and  25 . These can be seen both in the plan view in  FIG. 3  and in the cross-sectional view in  FIG. 4 , but not in the 90° rotated view in  FIG. 5 . 
     The connection piece  20  is preferably made of a hard plastic. 
     As shown in  FIG. 6 , the second part  31  of the bayonet fitting is part of the earmold adapter  12 . This second part  31  is pivotally mounted in a hard outer shell  32  of the adapter  12 . The adapter shell  32  has an inner side  33  which, when the earpiece is worn in the auditory canal, faces toward the eardrum. A piece of the second part  31  of the bayonet fitting projects from said inner side  33 . This can also be seen in  FIG. 7  which shows a plan view onto the adapter  12  from this inner side. 
     Inside the second part  31  of the bayonet fitting there runs, coaxially with the bayonet fitting, a sound channel  34  into which a cerumen protection device  35  is inserted. The receiver connecting piece  20  is pushed into the adapter  12  from the side opposite the inner side  33 . During insertion the lateral surfaces  24  and  25  can pass a corresponding recess  36  of the second part  31  of the bayonet fitting. Said recess  36  can be seen in  FIG. 7  and is in one dimension only slightly larger than the distance between the two lateral surfaces  24  and  25 . In addition, the recess  36  is large enough in the second dimension to ensure that the conical section  21  of the receiver connecting piece  20  can be pushed through the recess  36  even with its uncut radii  39 . 
     In the customary manner for bayonet fittings, after the receiver connecting piece  20  has been pushed in, the second part  31  is rotated through a certain angle, in this case 90°. In order to be able to rotate the second part  31  easily, it has at least two flattened sides  37 ,  38  which project from the inner side  33 , thereby enabling the second part  31  of the bayonet fitting to be easily gripped and turned e.g. using a simple pair of pliers or fitting aid. The rotated state of the bayonet fitting is shown in  FIGS. 8 and 9 . In the sectional view in  FIG. 8  it can now be seen that the recess  36  is engaged from behind by the conical section  21 . This means that the receiver connecting piece  20  is now firmly anchored in the adapter  12 . This anchoring is shown schematically in the plan view in  FIG. 9 . A rounded section  39  of the conical section  21  projects beyond the recess  36  so that the bayonet fitting is closed and the receiver connecting piece  20  is anchored in the adapter  12 . 
     Between the conical section  21  of the receiver connecting piece  20  and the second part  31  of the bayonet fitting there can be disposed a seal  13  (not shown in drawings  6  and  8  but visible in  FIG. 2 ). With the aid of this soft seal relative to the receiver connecting piece  20  and the outer shell  32 , the cone  21  is sealed with the fitting on the receiver sound outlet side. This soft part at the same time enables the force for opening and closing the bayonet fitting to be adjusted. 
     Another alternative design of the external receiver, i.e. of the earpiece according to the invention, consists in that no separate adapter  12  is used, but the second part  31  of the bayonet fitting is pivotally mounted directly in the ear shell. 
     With the above-described design of an earpiece and receiver coupled to one another by means of a bayonet fitting, the receiver  11  can be removed with much less force from the ear shell or more precisely the earmold  10 , leaving the receiver unit undamaged. In addition, a cerumen protection device  35  can also be inserted in the earpiece or more precisely in the adapter  12  without it having to be replaced each time the receiver is removed. Daily cleaning of the “receiver and earmold” unit is therefore possible.