Abstract:
A hearing apparatus includes a charging contact being movable relative to an accumulator and being electrically conductively connected to the accumulator in a first position and less effectively conductively connected thereto in a second position. A spring-elastic element engages with the charging contact in order to push the charging contact into the second position with a predetermined force, so that the charging contact can only be pushed into the first position by overcoming the predetermined force. As a result, the charging contact configuration obtains a switching function, so that electro-corrosion on the charging contacts can be prevented. Therefore, charging an accumulator of a hearing apparatus and in particular of a hearing device using a direct conductive contact is possible, with zero potential of the charging contacts which are accessible from the outside being ensured during normal operation of the hearing apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority, under 35 U.S.C. §119, of German Patent Application DE 10 2007 035 713.5, filed Jul. 30, 2007 and European Patent Application EP 07 12 1499, filed Nov. 26, 2007; the prior applications are herewith incorporated by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a hearing apparatus with a signal processing device for processing an input signal to form a sound output signal, an accumulator for supplying power to the signal processing device and a charging contact for feeding electrical energy into the accumulator. The term hearing apparatus is understood in this case to mean, in particular, a hearing device, but also any other wearable sound-emitting device such as a headset, earphones and the like. 
     Hearing devices are wearable hearing apparatuses, which are used to assist the hearing impaired. In order to accommodate numerous individual requirements, various types of hearing devices are available such as behind-the-ear (BTE) hearing devices, hearing device with an external receiver or receiver in the canal (RIC) and in-the-ear (ITE) hearing devices, for example concha hearing devices or completely-in-the-canal (ITE, CIC) hearing devices as well. The hearing devices listed as examples are worn on the outer ear or in the auditory canal. Bone conduction hearing aids, implantable or vibrotactile hearing aids are also available on the market. Damaged hearing is thus stimulated either mechanically or electrically. 
     The key components of hearing devices are principally an input converter, an amplifier and an output converter. The input converter is normally a receiving transducer e.g. a microphone and/or an electromagnetic receiver, e.g. an induction coil. The output converter is most frequently realized as an electroacoustic converter e.g. a miniature loudspeaker, or as an electromechanical converter e.g. a bone conduction hearing aid. The amplifier is usually integrated into a signal processing unit. That basic configuration is illustrated in  FIG. 1  using the example of a behind-the-ear hearing device. One or a plurality of microphones  2  for recording ambient sound are built into a hearing device housing  1  to be worn behind the ear. A signal processing unit  3 , which is also integrated into the hearing device housing  1 , processes and amplifies the microphone signals. An output signal of the signal processing unit  3  is transmitted to a loudspeaker or receiver  4 , which outputs an acoustic signal. Sound is transmitted through a sound tube, which is affixed in the auditory canal through the use of an otoplastic, to the device wearer&#39;s eardrum. Power for the hearing device and, in particular, for the signal processing unit  3 , is supplied through the use of a battery  5  which is also integrated in the hearing device housing  1 . 
     Hearing devices and other hearing apparatuses are in many cases equipped with accumulators (storage battery and/or rechargeable battery) in order to power their electronics system. The accumulators are mostly charged in such a way that the accumulators can remain in the hearing device during the charging process. Contacts which are accessible from the outside are thus provided on the housings of the hearing devices and/or hearing apparatuses. Electrical energy can be fed into the respective accumulator by a charging circuit, by way of the contacts. This means that provision can be made for a direct conductive contact between the charging circuit and the storage battery remaining in the device in order to charge the accumulators in the devices. 
     The conductive contact, also known as a charging contact, which is accessible from the outside, should have zero potential during normal operation of the device. However, the charging contacts attached to the housing exterior of the hearing devices are generally constantly energized. That presents a psychological problem on one hand and on the other hand additional corrosion could occur if they come into contact with perspiration, for instance, as a result of the electrical voltage at the contacts. 
     In order to avoid the problem of corrosion, charging circuits are also known which transmit the electrical energy to the hearing devices to be charged in a contactless manner using coils (inductive charging). Hearing devices are also known which do not have any charging contacts that are accessible from the outside. In those instances, the charging is effected through the use of a direct electrical contacting of the storage battery after a battery compartment is opened. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a hearing apparatus with a moveable charging contact, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, which can be easily charged from the outside by way of charging contacts and with which the charging contacts substantially have zero potential during normal operation. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a hearing apparatus, comprising a signal processing unit for processing an input signal to form a sound output signal, an accumulator for supplying power to the signal processing unit, and a charging contact for feeding electrical energy into the accumulator. The charging contact is movable relative to the accumulator between a first position in which the charging contact is electrically conductively connected to the accumulator and a second position in which the charging contact is less effectively conductively connected or not connected to the accumulator. A spring-elastic element engages the charging contact for pushing the charging contact into the second position with a predetermined force and permitting the charging contact to be pushed into the first position only by overcoming the predetermined force. 
     On one hand, the moveable charging contact advantageously provides for an electrical contact when charging and on the other hand, zero potential during normal operation. This mechanical structure does not require complicated electrical circuitry, thereby ensuring zero potential during normal operation. 
     In accordance with another feature of the invention, the spring-elastic element may have a rubber sleeve, which surrounds the charging contact. A rubber sleeve of this type not only ensures the reset force of the charging contact but also its insulation at the periphery. 
     In accordance with a further feature of the invention, the spring-elastic element may also have a metallic spring or a plastic spring, which is fastened to a housing of the hearing apparatus. If the plastic spring is injection-molded onto the housing in one piece, the number of components of the hearing apparatus can thus be reduced. 
     In accordance with an added feature of the invention, the spring-elastic element can also include a self-resetting, compressible film, which has a lower electrical resistance in the compressed state than in the uncompressed state. A film of this type provides for electrical contacting during the charging operation and for zero potential during normal operation, with the most minimal installation space requirement. 
     In accordance with an additional feature of the invention, in the first position, the charging contact preferably contacts the accumulator by way of a battery spring. This allows the operating sphere of the charging contact to increase as compared with the instance in which the charging contact directly contacts the accumulator. 
     In accordance with yet another feature of the invention, the charging contact can also have a contact surface which, in the first position, is in contact with a second contact surface of an accumulator contact, which for its part is connected to the accumulator. The accumulator contact, which can be realized, in particular, as a spring contact, allows an indentation depth of the charging contact to be varied significantly and the distance of the charging contact from the accumulator in the second position not to be predetermined. 
     In accordance with yet a further feature of the invention, by way of example, the charging contact forms a U-shaped contact configuration with the accumulator contact. The contact configuration has legs respectively formed by the charging contact and the accumulator contact and the two legs are connected to an insulator. The indentation depth and the tolerance, as to the extent to which the legs can be pushed past the contacting, can vary slightly depending on the distance between the contact surfaces and the insulator. 
     In accordance with a concomitant feature of the invention, it is advantageous if the insulator of the U-shaped contact configuration simultaneously forms the spring-elastic element. This multiple functionality can dispense with the need for an additional element. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a hearing apparatus with a moveable charging contact, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a diagrammatic, side-elevational view of an interior of a housing of a behind-the-ear hearing device including a basic circuit diagram of a construction of a hearing device according to the prior art; 
         FIG. 2  is a cross-sectional view of a charging contact with a rubber sleeve in a stand-by mode and/or during normal operation; 
         FIG. 3  is a cross-sectional view of the charging contact in  FIG. 2  during a charging process; 
         FIG. 4  is a cross-sectional view of a charging contact with a plastic spring in a stand-by mode; 
         FIG. 5  is a cross-sectional view of the charging contact in  FIG. 4  during a charging process; 
         FIG. 6  is a cross-sectional view of a charging contact with a compressible film in a stand-by mode; 
         FIG. 7  is a cross-sectional view of the charging contact in  FIG. 6  during a charging process; and 
         FIG. 8  is a cross-sectional view of a further embodiment of a charging contact. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now in detail to the figures of the drawings, which illustrate exemplary embodiments in more detail representing preferred embodiments of the present invention and first, particularly, to  FIG. 2  thereof, there is seen an accumulator  10  which is to be charged by way of a charging device contact  11  of a charging device.  FIG. 2  also shows a hearing device housing  12 , in which the accumulator  10  to be charged is disposed. For the sake of clarity, the representation of additional components of the hearing device within the hearing device housing is omitted. 
     A bore  13  is located in the hearing device housing  12  and a charging contact  14  is moveably mounted in the bore  13  at right angles to the hearing device housing  12 . In the present example, the charging contact  14  is configured in the manner of a cylinder and has a circumferential shoulder  15 . The charging contact  14  is also surrounded by a rubber sleeve  16 , which is insulating on one hand and has spring-elastic properties on the other hand. The extension of the rubber sleeve  16  in the longitudinal direction and/or direction of motion of the charging contact  14  is somewhat greater than the extension of the charging contact  14  from the shoulder  15  to a front face  17  of the contact  14 . As a result, a gap  18  is produced between the front face  17  of the contact  14  and a battery spring  19 , which produces an electrical contact between the charging contact  14  and the accumulator  10  during a charging process. In the state illustrated in  FIG. 2 , the charging contact  14  is thus moved away from the battery spring  19  through the rubber sleeve  16  and strikes the hearing device housing  12  with its shoulder  15 . The shoulder  15  thus not only provides for a contact surface of the rubber sleeve  16 , but is also used as a stopper of the charging contact  14  on the hearing device housing  12  when the charging contact  14  moves away from the battery spring  19 . 
     While a normal operating state and/or stand-by mode of the charging contact  14  is shown in  FIG. 2 ,  FIG. 3  shows a charging state. The charging device contact  11  is pushed onto the charging contact  14  in accordance with an arrow  20 , as a result of which the charging contact  14  is in turn pushed onto the battery spring  19  against the spring force of the rubber sleeve  16 , with direct electrical contact with the battery spring  19  being established on the front side of the charging contact  17 . The rubber sleeve  16  is compressed between the shoulder  15  of the charging contact  14  and the battery spring  19  to such a degree that an air gap no longer exists between the charging contact  14  and the battery spring  19 . A charging current thus flows from the charging device contact  11  through the charging contact  14  into the hearing device and through the battery spring  19  to the accumulator  10 . 
     At least one of the charging contacts which is accessible from the outside thus has no contact with the storage battery in the normal operating state of the preferred exemplary embodiment described in more detail on the basis of  FIGS. 2 and 3 . It is in fact separated from the storage battery  10  by way of a structural distance. The contact between the charging circuit and the storage battery  10  is first established by way of the charging contact  14 , if the charging device links the charging contact electrically with the accumulator  10  and/or the battery spring  19  through the use of a mechanical movement. 
     An additional exemplary embodiment of the invention is shown diagrammatically in  FIGS. 4 and 5 . The components, including the accumulator  10 , the charging device contact  11 , the hearing device housing  12 , the bore  13  and the battery spring  19  are likewise embodied in this case like they are in the preceding exemplary embodiment. A charging contact  24  is likewise embodied cylindrically in its basic form in this case. Naturally, it can similarly be square or have another suitable three-dimensional construction. It also has a projection  25 , which is disposed on one side in this case, but may similarly have an annular shape like the shoulder  15  of the preceding example. A metallic or plastic spring  26  is attached to the hearing device housing  12 . If applicable, it is directly injection-molded onto the plastic housing  12  or screwed thereto. The plastic spring  26  holds the charging contact  24  against the protrusion  25 , so that an air gap  18  is in turn produced between the charging contact  24  and the battery spring  19  in the stand-by mode shown in  FIG. 4 . In this stand-by mode, the protrusion  25  strikes the interior of the hearing device housing  12 , so that a movement of the charging contact  24  in the direction out of the hearing device housing  12  is restricted. 
     If, in accordance with  FIG. 5 , the charging device contact  11  is pushed onto the charging contact  24  as in the example shown in  FIG. 3 , the charging contact  24  moves downwards against the spring force of the plastic spring  26  and contacts the battery spring  19  directly. If the charging device contact  11  is removed again from the charging contact  24  opposite to the direction of motion  20 , the latter moves upwards, driven by the spring force of the plastic spring  26 , and/or somewhat out of the hearing device housing  12 . As a result, the air gap  18  between the charging contact  24  and the battery spring  19  adjusts again to the front face  27  of the charging contact. The electrical contact is thus interrupted again. 
     A third exemplary embodiment of a hearing apparatus with a charging contact configuration according to the invention is shown in  FIGS. 6 and 7 . The components including the charging device contact  11 , the hearing device housing  12 , the charging contact  14 , the shoulder  15 , the charging contact front side  17 , the battery spring  19  and the accumulator  10 , also correspond in this case to the correspondingly identically numbered components of the first exemplary embodiment according to  FIG. 2  and  FIG. 3 . A compressible foil  30  is located in this case between the front face  17  of the charging contact and the battery spring  19 . In the state illustrated in  FIG. 6 , the film  30  is uncompressed and is thus insulating. It also has spring-elastic properties and pushes the charging contact  14  with its shoulder  15  against the hearing device housing  12 . 
     The charging device contact  11  is also pushed downwards for the charging process, i.e. onto the battery spring  19 , according to the direction of motion  20 . The foil  30  is therewith compressed according to  FIG. 7 . The foil  30  is electrically conductive in this compressed state. In other words, the compressible foil  30 , which is located between the charging contact  14  and the inner contact and/or the battery spring  19 , and which is highly-resistive and/or insulating in the stand-by mode according to  FIG. 6 , becomes low-resistive and conductive as a result of the pressure exerted thereupon. In this case the charging contact  14  is generally only moved and/or displaced marginally. In any case, the mechanical deformation of the foil  30  during compression is sufficient to change the electrical properties of the foil  30  with respect to its electrical resistance in such a way that a charging current can flow from the charging device to the accumulator  10 . 
       FIG. 8  shows a cross-section of a fourth exemplary embodiment of a hearing apparatus with a charging contact configuration according to the invention. A charging contact  40  is integrated flush with a hearing device shell  12  with its surface directed outwards. The charging contact  40  has an oblong contact section  41  in the interior of the hearing device shell  12 . A battery spring  42 , which is disposed parallel thereto, is continuously connected to the battery and/or accumulator  10 . It is likewise embodied in this case to be oblong, with one of its ends being connected to an end of the oblong contact section  41  of the charging contact  40  by way of an insulator  43 . A U-shaped construction of the components, including the charging contact  40 , the insulator  43  and the battery spring  42  thus results in the cross-section. The insulator  43  has spring-elastic properties and holds the two legs of the U-shaped configuration, namely the charging contact  40  and the battery spring  42 , in the position shown in  FIG. 8  (second position), in which the two components do not touch and are thus not electrically connected. 
     The charging contact  40  has a contact bump and/or a contact surface  44  made of conductive metal on the side which the battery spring  42  faces. The battery spring  42  likewise has a contact bump and/or contact surface  44  on its side facing the charging contact  40 . As soon as the two contact surfaces  44  touch, the charging contact  40  is electrically connected to the battery spring  42 . This is then the case if a contact  45  of a charging station pushes a charging section  46  of the charging contact  40 , which is accessible from the outside, downwards and/or inwards. In the depressed state, the two contact surfaces  44  are then shorted and a charging current can flow from the contact  45  of the charging station through the charging contact  40 , the contact surfaces  44  and the battery spring  42  into the accumulator  10 . At the end of the charging process, i.e. when removing the contact  45  from the charging station, the spring-elastic insulator  43  provides for the charging contact  40  to be DC-isolated or galvanically separated again from the battery spring  42 . 
     Alternatively to the spring-elastic insulator  42 , provision can also be made, for instance, for a spring-elastic element, e.g. a plastic spring to be disposed in the vicinity of the charging section  46  between the charging contact  40  and the battery spring  42 , in order to ensure the necessary reset force. In this instance, the insulator  43  only has a joining function. 
     As a further alternative, the charging contact  40  and the battery spring  42  can also be directly injection-molded into the housing shell  12 , if the charging contact  40  itself is spring-elastic. In this case, the hearing device shell  12  adopts the insulator function. In this exemplary embodiment, the spring-elastic element is thus directly integrated into the charging contact and/or is formed in one piece therewith. By way of example, the oblong contact section  41  thus then forms the spring-elastic element. 
     The spring force, against which the charging section  46  has to be pushed downwards in order to establish an electrical connection to the battery spring  42 , can be adjusted slightly in the desired fashion with this U-shaped configuration. It is thus possible to select not only the modulus of elasticity of the insulator  43  and of the oblong contact section  41 , but also the length of the contact section  41  accordingly. 
     An indentation depth of the charging section  46  can also be very effectively varied with this construction. A minimum indentation depth is defined in this case in that the two contact surfaces  44  touch. Furthermore, the charging section  46  can also be pushed deeper, i.e. the charging contact  40  can be over-pushed, since the contact surfaces  44  are not located directly below the charging section  46 , but instead at a position of the oblong section  41  between the charging section  46  and the insulator  43 , e.g. in the center region thereof. One part of the oblong section  41  is thus located between the contact surfaces  44  and the charging section  46 , which can also be pushed downwards following a previously effected contacting process. As a result, the indentation depth, which results from the contact  45  of the charging station, can be kept in a large tolerance range, with it consequently being ensured that the electrical connection to the accumulator  10  is established reliably. 
     The embodiment of one or both charging contacts of the hearing apparatus according to the invention only allows the charging contacts which are accessible from the outside to be connected to the internal voltage source (accumulator  10 ) during the charging process. The charging contact configuration embodies a switching function in a certain way. The advantages of this charging contact configuration lie in it being possible for the charging device to remain simple and robust in terms of its construction. Furthermore, electro-corrosion is avoided due to the zero potential of one or both charging contacts and a current flow across the skin is ruled out in the case of a random simultaneous main contact of the two charging contacts. A simple measurement and monitoring of the accumulator is still also possible during operation, through the use of charging contacts which are accessible from the outside, if the switching function is triggered with the measurement device.