Abstract:
An object containing electronic circuits and a rechargeable cell, wherein the cell is arranged close to a surface of the object, a charge coil being shiftable with respect to the cell between an operating position where it is arranged around the cell and a recharge position where it is axially offset with respect to the cell.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of French Patent Application No. 12/61548, filed Dec. 3, 2012, and which application is hereby incorporated by reference to the maximum extent allowable by law. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an object of small dimensions (on the order of one centimeter) containing electronic circuits powered by a cell. It more specifically relates to such an object containing a rechargeable cell having a non-negligible power consumption, the cell having to be able to provide an energy greater than 8 milliamperes-hour to offer 12 hours of autonomy. The present disclosure especially applies to in-the-ear hearing aids. 
     2. Discussion of the Related Art 
     The general appearance of an in-the-ear hearing aid is illustrated in  FIG. 1 . Such a hearing aid has an anatomic shape capable of being inserted in the external auditory canal. Generally, hearing aid  1  comprises a substantially planar surface  3  which, once the hearing aid has been inserted into the auditory canal, faces outwards. Preferably, for aesthetic reasons, the hearing aid is sized to avoid substantially protruding from the auditory canal. Such a hearing aid contains various electronic circuits for receiving, amplifying, adapting, and retransmitting sound signals, adapted to the hearing impairment which is desired to be overcome. Such electronic circuits have to be powered. Accordingly, a cell  5 , inserted on the side of surface  3  in a cavity closed by a shutter  7 , is provided. 
     An in-the-ear hearing aid has small dimensions. Calling H its largest dimension such as indicated in  FIG. 1 , conventional values of H range between 12 and 18 mm. The largest lateral dimension L approximately ranges from 8 to 12 mm. As a result, only cells of small dimensions may be inserted in such a device, for example a cell having a diameter ranging between 4 and 8 mm for a height ranging between 2 and 5 mm, for example, a cell having a 5.5-mm diameter and a 4-mm height. Further, such hearing aids have a relatively high power consumption, greater than 0.5 milliamperes in average, that is, in practice, with non-rechargeable cells, an autonomy on the order of one week at best can be reached, which results in a very high cell replacement cost. Further, when a rechargeable cell is used, the device power consumption results in that, with a rechargeable cell having the above-indicated dimensions, a recharge has to be provided practically every night. Thus, a user who would nevertheless like to use a rechargeable cell should, every day (against once a week for a disposable cell), perform a cell removal operation, an operation of recharge thereof, and an operation of putting back the cell in place. Given the small cell dimensions, these operations are delicate, and this all the more as persons using a hearing aid often are elderly people having a limited visual acuity and dexterity. Mechanical devices for grabbing the cell, placing it on a charger, and putting it back in place have thus been provided. Such devices are, however, not always very easy to use, especially for elderly people. Further, such operations cause a fouling of electric contacts. 
     This problem of handling a small rechargeable cell is posed for hearing aids such as indicated hereabove, but also for many other devices of small dimensions with a relatively high power consumption, such as swallowable cells that may correspond to pills having a diameter approximately ranging from 6 to 8 mm, and generally for any device which is desired to be tight. 
     It should be noted that the above-mentioned problem of frequent change or of frequent recharge of cells of small dimensions is not posed for devices such as watches which have a very low power consumption and for which the lifetime of a cell may approximately range from 1 to 5 years. On the other hand, this problem is not posed either for devices of relatively large dimensions, such as watches or devices having the format of a credit card, for which a surface area is available, which is sufficient to have charge coils of relatively large diameter (several centimeters), which, despite a generally poor coupling with a primary, enable to provide a sufficient power due to their number of turns and to their diameter. 
     There thus is a need for an electric object provided with a rechargeable cell which does not need being extracted from the object in order to be recharged. 
     SUMMARY 
     Thus, an embodiment provides an object containing electronic circuits and a rechargeable cell, wherein the cell is arranged close to a surface of the object, a charge coil being shiftable with respect to the cell between an operating position where it is arranged around the cell and a recharge position where it is axially offset with respect to the cell. 
     According to an embodiment, the object has a maximum dimension smaller than 20 mm, the cell being cylindrical and having a diameter smaller than 6 mm and a height smaller than 4 mm. 
     According to an embodiment, the object forms an in-the-ear hearing aid. 
     According to an embodiment, the charge coil is fixedly attached to the body of the object and the cell is shiftable away from the above-mentioned surface. 
     According to an embodiment, a portion of the object located above the cell opposite to the above-mentioned surface is shiftable along with the cell with respect to the body of the object. 
     According to an embodiment, the object comprises ratchet means for maintaining the object in operating position. 
     According to an embodiment, the object comprises locking means for preventing said portion of the object from sliding beyond the recharge position. 
     An embodiment provides a system for recharging an object such as hereabove, comprising a pad supporting, around a ferromagnetic core, a winding having an external diameter corresponding to the internal diameter of the charge coil. 
     According to an embodiment, the pad comprises means for heating the cell. 
     The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 , previously described, schematically shows an in-the-ear hearing aid; 
         FIG. 2  is a still more simplified representation of a small object containing a rechargeable cell; 
         FIGS. 3A and 3B  show a rechargeable cell system, respectively in operating position and in recharge position; and 
         FIGS. 4A and 4B  show a small object provided with a system of the type described in relation with  FIGS. 3A and 3B  in operating position and in recharge position. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  is an extremely simplified cross-section view of a small object provided with a rechargeable cell. This small object is illustrated in the form of a frustum. As in  FIG. 1 , the small object is designated with reference numeral  1 . One of its surfaces, having the rechargeable cell mounted thereon, is designated with reference numeral  3  and the rechargeable cell is designated with reference numeral  5 . It should be noted that surface  3  does not necessarily have a planar surface and that the simplified frustum shape of  FIG. 2  is only illustrated to simplify the drawings. The small object may have any desired shape, for example, a shape of the type in  FIG. 1  for a hearing aid, or even a capsule shape for a swallowable pill provided with electronic means for analyzing internal organs of the body and/or medication. It will then for example be an object having a spherical or ellipsoidal shape. 
       FIGS. 3A and 3B  show an assembly  10  of a cell and of its charge system, respectively in operating position and in recharge position. It is provided to replace rechargeable cell  5  of  FIGS. 1 and 2  with an assembly  10  such as illustrated in  FIGS. 3A and 3B . Assembly  10  comprises a cell  12  surrounded with a ring  13  around which is wound a coil  14 . This coil is connected by connection elements  15  to a charge circuit  16 . Ring  13  with coil  14  is shiftable along the axis of cell  12 . Given that, as will be seen hereafter, assembly  10  is mounted in an object in a particularly simple and easy-to-use way, it may be provided for rechargeable cell  12  of assembly  10  to be frequently recharged. Cell  12  may conveniently have dimensions slightly smaller than those of cell  5  illustrated in  FIGS. 1 and 2 , so that assembly  10  occupies substantially the same volume as cell  5 . 
     Assembly  10  may take one or the other of two configurations. In a first configuration illustrated in  FIG. 3A , which corresponds to an operating position, coil  14  is arranged around the rechargeable cell. In a second configuration illustrated in  FIG. 3B , which corresponds to a recharge position, coil  14  is shifted along the axis of the rechargeable cell so that its internal portion is accessible. Connection elements  15  connect the terminals of coil  14  across charge circuit  16 . Thus, such connection elements must remain efficient in the two positions illustrated in  FIGS. 3A and 3B . They will for example be fold-out wires, flexes, or rail and cursor systems. 
     Charge circuit  16  corresponds to conventional circuits known in the art intended to rectify an A.C. signal provided by coil  14  when it is coupled to a primary winding and to carry out various regulation functions intended to provide an optimal charge of a rechargeable cell. It may also integrate a conversion of the battery output voltage (such as a voltage step-down circuit), which offers more choice as to the battery technology and to its associated voltage. Such known circuits may be contained within a wafer  16  having a thickness on the order of 1 mm and a diameter which is not greater than that of the cell, that is, from 5 to 8 mm. 
     As indicated, the possibility of a relative translation motion between cell  12  and charge circuit  16 , on the one hand, and the assembly of ring  13  and of coil  14 , on the other hand, is provided. It may be provided for the assembly of the rechargeable cell and of circuit  16  to be fixed with respect to the body of object  1 . In this case, the assembly of the ring and of the coil must be pulled towards the outside to a recharge position, for example, by means of a small tab or of any other means for grasping coil  14 . In the recharge position illustrated in  FIG. 3B , a primary winding connected to a system for providing an A.C. current is inserted into ring  13  to provide power to winding  14  which then forms a secondary winding. It should be noted that the primary winding, due to its hollow cylindrical shape, may easily contain a cylindrical ferrite core having a diameter slightly smaller than that of the primary coil. Such a core provides a very good coupling between the two coils, even at low frequencies, and does not interfere with the operation of assembly  1  (in particular with its microphone and its loudspeaker) when it is removed from its recharge base. 
       FIGS. 4A and 4B  illustrate an embodiment of the recharge system. A small object  20  is divided into two main portions shiftable with respect to each other. The first portion comprises cell  12  and circuit  16  for charging a system  10  such as previously described, topped with a block  22 , for example, especially comprising all the electronic circuits of object  20 . This first portion is surrounded with a second portion  23 . First portion  22  is mobile with respect to second portion  23  between a position, illustrated in  FIG. 4A , where the object has its “normal” operating shape, and a recharge position, illustrated in  FIG. 4B , where the first portion is shifted upwards while ring  13  and winding  14  remain fixed with respect to second portion  23 . Locking and/or ratchet means, not shown, are preferably provided to ascertain that each of the portions illustrated in  FIGS. 4A and 4B  is stable. 
     As very schematically shown in  FIG. 4B , to switch to the recharge position, object  20  is arranged above a charge system  30  comprising a protruding pad  32  provided with a winding  34  wound around a ferrite core or another ferromagnetic material  35  having object  20  bearing against it to have the first portion slide with respect to the second portion. Charge system  30  conventionally comprises electronic circuits  36  capable of supplying coil  34  with an A.C. current to transfer power into coil  14  once the two windings  14  and  34  have been placed in front of each other. 
     To return to the normal operating position, it is sufficient to lay the object, the cell facing downwards, on a substantially planar surface and to press on the top of portion  22  (or conversely). 
     It should be noted that charge system  30  may also comprise in its upper portion a heating element for heating rechargeable cell  12  during its recharge. Indeed many types of rechargeable batteries, such as lithium metal batteries recharge much faster when their temperature is higher than the usual temperature, for example, when their temperature approximately ranges from 40 to 50° C. 
     It should be understood that many variations may be brought to the device described herein without departing from the field of the invention. For example, instead of providing a coil assembled on a ring, an autonomous coil, for example, a coil embedded in a resin, may be provided. 
     Charge systems such as system  30  of  FIG. 1  may be formed from many existing devices, for example, devices generally associated with laptop computers. 
     Further, although this has not been described, it should be clear that connections should be provided between the cell, the recharge circuit, and the various electronic circuits contained in the object. 
     Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and the scope of the invention. Accordingly, the foregoing description is by way of example only and is not intended to be limiting. The invention is limited only as defined in the following claims and the equivalents thereto.