Patent Publication Number: US-8126177-B2

Title: Modular charger for hearing aid

Description:
BACKGROUND 
     This invention relates to a hearing aid having at least one rechargeable battery, and in particular, to a recharging system that is easily configured to receive hearing aids of distinct shapes and sizes. 
     Hearing aids having rechargeable batteries have been known in the art for a long time; e.g., see U.S. Pat. No. 3,297,933 (McCarthy). The trade-off between rechargeable batteries and non-rechargeable batteries is the inconvenience of having to replace a battery. There is also a trade-off in capacity. A non-rechargeable battery lasts much longer than a rechargeable battery having the same outside dimensions as the non-rechargeable battery. This is due to the different chemistries of the two types of batteries. 
     The inconvenience of having to remove the battery from a hearing aid initially applied both to rechargeable batteries and non-rechargeable batteries. The sole advantage of rechargeable batteries was not having to be replaced. Then, chargers were developed that made electrical contact with a hearing aid, obviating the need to remove the rechargeable battery; e.g. see U.S. Pat. No. 3,493,695 (Stork). This simplified matters for those lacking the dexterity to remove and insert a battery. 
     A problem remains with the diversity of hearing aids on the market. The most obvious difference is between in-the-ear hearing aids and behind-the-ear hearing aids. Even within a given type, there are variations in shape and size that must be accommodated. Preferably, each hearing aid is held optimally so the user can readily insert and remove the hearing aid from the charger. The cost of manufacturing and storing the various unique chargers can add considerably to the cost of a hearing aid system, even if the charger can charge two hearing aids simultaneously. 
     Simply making a chamber large enough to drop in a hearing aid of almost any shape does not assure proper contact for charging. A hearing aid must be positioned correctly to assure electrical contact. Within a charger, the contact leaves or pins must be properly aligned for contact and be able to withstand repeated use. 
     In view of the foregoing, it is therefore an object of the invention to provide a battery charger that can be adapted to hearing aids of distinctly different shapes and sizes. 
     Another object of the invention is to provide a battery charger for a hearing aid that reliably connects electrically to the hearing aid. 
     A further object of the invention is to reduce the cost of manufacturing battery chargers for hearing aids. 
     SUMMARY OF THE INVENTION 
     The foregoing objects are achieved by this invention in which a battery charger for a hearing aid includes a housing that defines at least one socket for receiving any one of a plurality of adapters. Each adapter closely fits and at least partially contains one hearing aid to hold the hearing aid in place during charging. The hearing aid includes a plurality of electrical contacts in a pattern and the adapter defines a plurality of apertures in the same pattern. Resilient contacts in the charger extend through the apertures in the adapter to contact the hearing aid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the invention can be obtained by considering the following detailed description in conjunction with the accompanying drawings, in which: 
       The FIGURE is an exploded view of a preferred embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the FIGURE, charger  10  includes base  11  and cover  12  of suitable shape and volume for containing the electronics (not shown) that actually charges one or more batteries in one or more hearing aids. Cover  12  includes socket  14 . Although illustrated as somewhat rectangular, socket  14  can have any desired shape. In accordance with the invention, a custom adapter fits within socket  14  to hold a hearing aid having a particular shape in place for charging. 
     In a preferred embodiment of the invention, adapter  15  includes floor  16  and shells  17  and  18 . Although an adapter could be made in a single piece, the shells can have intricate shapes and yet be easily released from a mold. Floor  16  can be molded as part of either shell. Adapter  15  fits within socket  14  and adapts charger  10  to a particular hearing aid or model of hearing aid. Adapter  15  can be made from any suitable material. A resilient plastic is preferred. 
     Adapter  15  preferably includes a lip for engaging cover  12  and preventing adapter  15  from passing through cover  12 . A dado or shoulder is preferably formed in rim  19  of socket  14  for receiving a lip, thereby providing a smooth upper surface on cover  12  when adapter  15  is in place. 
     The outer surface of adapter  15  is shaped to pass through socket  14 . The inner surface of adapter  15  is shaped to receive a particular hearing aid, such as hearing aid  21 . Hearing aid  21  can be held by frictional engagement, by interference fit (such as a bead and groove), or by other means to keep hearing aid  21  in the proper position for charging. 
     As illustrated in the figure, hearing aid  21  includes three rectangular apertures  23  through which electrical contact is made to the hearing aid. Adapter  15  defines apertures  30  that align with the apertures in hearing aid  21 . When adapter  15  is inserted into socket  14  and cover  12  is attached to base  11 , resilient contacts  31  within base  11  extend through the aligned apertures to provide contact between the electronics in base  11  and hearing aid  21 . Contacts  31  are preferably molded into plastic carrier  32  for precise, durable alignment. 
     The invention thus provides a battery charger that can be adapted to hearing aids of distinctly different shapes and sizes and that reliably connects electrically to the hearing aid. The cost of manufacturing battery chargers for hearing aids is reduced because the housing and the electronics can remain the same, only the adapter changes. That is, a single housing can accept a plurality of adapters but each adapter is designed to closely fit a single hearing aid or single type of hearing aid. Resilient contacts molded into a plastic carrier reduce dimensional tolerances and simplify production. The adapter can have a complex internal structure, e.g. undercuts, without significantly increasing the overall cost of the charger. Developing a new hearing aid does not require developing a new charger. One simply changes adapters. This simplifies development and testing of new designs. 
     Having thus described the invention, it will be apparent to those of skill in the art that various modifications can be made within the scope of the invention. For example, socket  14  could engage adapter  15  along the sides or bottom of the adapter, in addition to or instead of at rim  19 . Although the electrical connections described relate to charging, the electrical connections can be used for other purposes, such as programming a hearing aid from the charger. As indicated by dashed line  41 , charger  10  can optionally include adapters for more than one hearing aid. Base  11  and cover  12  form a container divided along an essentially horizontal plane. The container for the electronics of the charger can have any configuration, e.g. divided along a vertical plane or a clam-shell type of case. What matters is that the container include at least one socket for receiving adapter  15 . Each adapter could have its own set of resilient contacts in the apertures but it is preferred, and less expensive, that contacts  31  extend through empty apertures in the adapter to contact a hearing aid. One could use pogo pins for resilient contacts but a leaf spring type of contact is preferred because such a contact provides a self-cleaning, wiping action when a hearing aid is inserted into the charger. Base  11  is illustrated as solid. Holes for ventilation or electrical access are not shown as they do not relate to the invention.