Abstract:
A connector system for Behind-The-Ear (BTE) hearing devices provides a means to detachably connect a variety of accessories to a sound processor, including batteries, earhooks, telecoils, auxiliary microphones, FM receivers, and input jacks for miscellaneous devices. The present invention provides an efficient and economical sealing connection, eliminating the introduction of sweat, body fluid and other contaminants into the connection area, which otherwise would result in corrosion and eventually disable the connected device. A wiping contact formed by a configuration of cam contacts and a flex circuit with a configuration of corresponding contacts is combined with a rotational engagement mechanism to create a vibration-resistant high contact density connector that is moisture proof when engaged.

Description:
RELATED APPLICATIONS 
     The present application is a national stage application under 35 U.S.C. 371 of International Application No. PCT/US10/33574, filed May 4, 2010, which in turn claims priority to U.S. Provisional Patent Application No. 61/175,451 by William Dai et al., filed on May 4, 2009, and entitled “MULTI-CONTACT CONNECTOR SYSTEM,” the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF INVENTION 
     The present invention relates to hearing devices for aiding the hearing impaired and the profoundly deaf, and more particularly to a multi-contact connector system providing electrical and mechanical connection between an external sound processor and a battery, earhook, or other accessory desired to attach to the sound processor. The connector system of the present invention is useful for conventional hearing aids and for cochlear stimulation systems employing Behind-The-Ear (BTE) and body worn sound processors, and for other devices requiring a mechanically stable and robust sealing connector having multiple contacts. 
     Implantable Cochlear Stimulation (ICS) systems are known in the art. Such systems are used to help the profoundly deaf to hear. The sensation of hearing is achieved by directly exciting the auditory nerve with controlled impulses of electrical current, which impulses are generated as a function of audio sounds picked up by a microphone carried externally by the deaf person and converted to electrical signals. The electrical signals, in turn, are processed by a sound processor, e.g., converted to a sequence of pulses of varying width and/or amplitude, and then transmitted to an implanted receiver circuit of the ICS system. The implanted receiver circuit then generates electrical current as a function of the processed signal it receives from the sound processor. The implanted receiver circuit is connected to an implantable electrode array that has been inserted into the cochlea of the inner ear. The electrical current generated by the implanted receiver circuit is applied to individual electrode pairs of the electrode array to stimulate the auditory nerve and provide the user with the sensation of hearing. 
     The sound processor is powered by batteries that typically have a limited life before they need to be recharged or replaced. These devices are often worn by children and the elderly, and the batteries may be detached and reattached by the patient one to several times a day. Therefore, their battery connection must be both easy to work and robust. In addition to batteries, users of hearing aids and cochlear implants have requirements to attach a variety of auxiliary devices to the sound processor to augment the basic hearing function. These devices include earhooks, telecoils, auxiliary microphones, FM receivers, audio jacks, and the like, and they may be attached and detached as needed for various activities throughout the day. Many of these devices are capable of transmitting and/or receiving information, which may be analog or digital. 
     ICS systems typically include an external headpiece positioned on the side of the user&#39;s head for communicating with the cochlear implant and connected to the sound processor via an external cable. While some sound processors are carried by the user on a belt or in a pocket, others are worn behind the ear (BTE), greatly increasing the exposure to sweat. A particular problem associated with cochlear stimulators and related medical devices is corrosion. When sweat, bodily fluids, and other contaminants come in contact with the battery terminal or an accessory&#39;s electrical contacts, corrosion occurs, which, left unchecked, would eventually disable the system, or at least disable the accessory. The integrity of the connection between the battery or other accessory and the sound processor is critical for proper function and safety. The connection must prevent the introduction of foreign matter, such as body fluids and other contaminants that may compromise the electrical connection. An effective, efficient solution is needed for this problem. 
     Another problem is medical device stability and ability to withstand vibration. The battery or accessory must be firmly connected to the sound processor in such a way as to avoid disconnection resulting in medical device malfunction leading to loss of hearing. Thus, in addition to ensuring a complete seal of the connection area between a battery or accessory and a medical device, the connection must also be mechanically sound. 
     As such, it is desirable to have a device that provides a simple, easy-to-use, inexpensive, reliable, robust connection and sealing mechanism and that efficiently and effectively addresses the problems found in the prior art. There is therefore a need to provide a small, lightweight means to reliably and detachably connect a battery, earhook, or other auxiliary device to a BTE sound processor. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by combining a wiping contact with a rotational engagement mechanism to create a vibration-resistant high contact density connector that is moisture proof when engaged. The multi-contact connector system serves as an electrical and mechanical attachment system for batteries, earhooks, and other accessories to a Behind-The-Ear (BTE) or body worn hearing device, such as telecoils, auxiliary microphones, FM receivers, and audio jacks, as part of either a hearing aid system or of a cochlear stimulation system. 
     The connector mechanism resembles a cam (male side) and cam follower (female side) mechanism. As used herein, the term “cam” means a curved wedge movable about an axis, which may be an axis of the cam itself or of a first connector of which it is a part, which forces contacts of the first connector against contacts of a second connector during rotation about the axis. In one embodiment, the cam comprises fixed metal contacts, creating a high density contact device with key and locking features. In one embodiment, the cam follower comprises a flex circuit held in tension around the perimeter of the cam. Both ends of the flex circuit are fixed to the connector housing and held in tension with a spring, such as an elastomeric spring. When the first connector and the second connector are rotated relative to each other about a mutual axis, the tension provided by the spring forces electrical contact between the cam and cam follower contacts throughout a customizable range of rotational movement. By not using the electrical contact itself to supply the spring force to maintain contact, the problem of fatigue in connectors known in the art can be eliminated. The customizable range of rotational movement can be designed to vary the self cleaning action of the wiping contacts. Instead of only adjusting wiping force to improve the self cleaning action, the connector designer may design the rotational range to increase the effective length of the wipe. The customizable range of rotation also increases design flexibility and/or reliability of the connection during vibration, since the first and second connectors may be allowed to rotate and maintain function during vibration about the axis. 
     The connector structure provides greater contact area than other contact designs, thereby increasing reliability. The compact size of the connector allows a size reduction of external hardware, increasing the aesthetic appeal and reducing weight. The compact size and contact density of the connector improve diagnostic tool usability, allowing analog and digital data streams to travel over one connection instead of through multiple cables. 
     A male connector and a female connector together provide the necessary mechanical stability. A strategically positioned sealing ring ensures a complete seal from the external environment. 
     Furthermore, the robust design is easily and efficiently manufactured at low cost with regard to both materials and labor. 
     The connector is easy to use by simply plugging the male connector into the female connector and twisting to make contact and lock. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a BTE hearing device utilizing the multi-contact connector system of the present invention; 
         FIG. 2  shows a multi-contact connector system made in accordance with the present invention; 
         FIG. 3  shows the male connector and female connector of the multi-contact connector system; 
         FIG. 4  shows an exploded view of the components of the multi-contact connector system; 
         FIG. 5  shows assembly of the cam contacts to the contact carrier to form a male contact assembly of a multi-contact connector system; 
         FIG. 6  shows the overmold of the male contact assembly to form a connector cam; 
         FIG. 7  shows sealing ring assembly onto the connector cam; 
         FIG. 8  shows trimmed leads of the connector cam to complete the male connector; 
         FIG. 9  shows adhesion of a spring to a flex circuit contact mount; 
         FIG. 10  shows wrapping of the flex circuit around the flex circuit contact mount to form a female contact assembly; 
         FIG. 11  shows installation of a moisture barrier cap onto the female contact assembly; 
         FIG. 12  shows epoxy filling the flex circuit contact feedthrough of the female connector; 
         FIG. 13  shows lock features of the female connector and key features of the male connector; 
         FIG. 14  shows camming features of the female connector and male connector with the connectors disengaged; 
         FIGS. 15A and 15B  are top and side perspective views, respectively, of the camming contact of  FIG. 14  as engaged; 
         FIGS. 16 and 16A  show top view and side cross section view, respectively, of the multi-contact connector system of the present invention; 
         FIGS. 17A and 17B  show side and front views of the female connector; 
         FIGS. 18A and 18B  show side and front views of the male connector; 
         FIGS. 19A and 19B  illustrate the no contact state and rotated contacting state between the cam contacts and the flex circuit contacts, respectively; 
         FIG. 20  illustrates an alternative embodiment of the invention; 
         FIGS. 21A ,  21 B,  22 A, and  22 B illustrate alternative embodiments of the invention; 
         FIG. 23  illustrates another alternative embodiment of the invention; 
         FIG. 24A-24D  illustrate another alternative embodiment of the invention; and 
         FIG. 25A-25C  illustrate yet another alternative embodiment of the invention. 
     
    
    
     Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. 
     DETAILED DESCRIPTION OF INVENTION 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. 
       FIG. 1  shows a Behind-The-Ear (BTE) sound processor  2000  utilizing the multi-contact connector system  1000  of the present invention to provide a mechanical and electrical connection for a battery  3000  and for an earhook  4000 . The earhook  4000  is arched and hooks in front of the ear, and is removably attached to the BTE sound processor  2000 . The BTE sound processor  2000  continues the arch and is positioned behind the ear. The battery  3000  is removably attached to the bottom of the BTE sound processor  2000 . Various batteries of different sizes may be interchangeably attached to the BTE sound processor, depending upon the needs of a user. Likewise, various earhooks having different functionality or size may be interchangeably attached to the BTE sound processor, again, depending upon the needs of the user. 
     The BTE sound processor  2000  is small and fits compactly behind the user&#39;s ear, and as a result, there is limited surface area available for connectors. The battery  3000  connects with the BTE sound processor  2000  via the insertion of the male connector  200  into the female connector  100  of the multi-contact connector system  1000 , providing mechanical stability for the assembled sound processor and battery, while wiping contacts provide the electrical connection that powers the implanted cochlear stimulator (not shown). Although the female connector  100  is illustrated as being on the sound processor  2000  and the male connector  200  is illustrated as being on the battery  3000 , these features may also be reversed. Likewise, although the female connector  100  is illustrated as being on the earhook  4000  mated to the male connector  200  on the BTE sound processor  2000 , this can also be reversed. 
       FIG. 2  shows a multi-contact connector system  1000  made in accordance with the present invention ready for engagement of the female connector  100  with the male connector  200 . (The moisture barrier cap  120 , shown in  FIG. 4 , has been removed to show detail.) 
       FIG. 3  shows the female connector  100  and male connector  200  of the multi-contact connector system  1000 . Although not shown, a cover for either the female or male connector or both may be provided to keep them clean when not in use. 
       FIG. 4  shows an exploded view of the components of the multi-contact connector system  1000 , including a moisture barrier cap  120 , a flex circuit  30 , a spring  20 , a flex circuit mount  10 , a sealing ring  220 , cam contacts  64 , a contact carrier  62 , and an overmold  70 . Assembly of these components will be described below. 
       FIGS. 5-8  illustrate assembly of the male connector  200 . As shown in  FIG. 5 , cam contacts  64  are placed onto a contact carrier  62  to form a male contact assembly  60 , shown in  FIG. 6 . Cam contacts  64  can be machined, stamped, laser cut, or otherwise manufactured using other precision forming processes. In one arrangement, a copper beryllium base is plated with 100 microinch nickel plating, and covered with a  10  microinch layer of hard gold. In one illustrative embodiment, the contacts  64  may have a width of about 0.020 inches with a separation between them of about 0.015 inches, creating a compact, high contact density connector. Contact carrier  62  can be machined or molded using various plastics forming processes. In one illustrative embodiment, contact carrier  62  is made of a high strength, moderate stiffness plastic, such as Ultem® 1000 polyetherimide thermoplastic, which is a biocompatible engineering plastic available from Sabic Innovative Plastics. In all components described herein as made of plastic, the component may be machined or molded, with molding generally more economical when made in larger quantities. Furthermore, the plastics may be the same or different from each other; providing materials of similar chemistry can be used to improve bonding between parts. Alternatively, contact carrier  62  can be made of elastomer to create a compliant male contact assembly  60  which will later be inserted into the male overmold  70  shown in  FIG. 6 . Making the male contact assembly  60  compliant allows it to act as a spring, thereby eliminating the need for a separate spring  20 , which spring will be described later with respect to  FIG. 9-12 . 
     As shown in  FIG. 6 , male contact assembly  60  is provided with an “overmold”  70  to form a connector cam  210 . Overmold  70  can be molded using various plastics forming processes. In an illustrative embodiment, overmold  70  is made of Ultem® 1000 plastic. Providing the materials of overmold  70  similar in chemistry to the material of contact carrier  62  can help ensure good bonding between them. Although not shown, overmold  70  may have a chamfer at the leading edge to aid insertion into the female connector. Alternatively, instead of overmolding male contact assembly  60  with overmold  70 , the male contact assembly  60  may be inserted into a separately manufactured overmold  70  which can be machined or molded using various plastics forming processes. 
     As shown in  FIG. 7 , sealing ring  220  is slid onto connector cam  210 . The sealing ring is designed and strategically positioned to fully seal the interface to prevent the introduction of body fluids and other contaminants to the active electrical connection. The sealing ring may be removable for replacement. For purposes of illustration, the sealing ring is shown to reside in a circular groove; however, other sealing ring and groove shapes, cross sections, and configurations can be used. Alternatively, the sealing ring  220  may remain in place by friction without residing in a groove. As another alternative, the sealing ring may be adhered to the connector cam  210 , such as by insert molding or adhesive bonding. In yet another alternative embodiment, the sealing ring  220  may be located within the female contact, adhered or within an optional groove (not shown). 
     As shown in  FIG. 8 , leads  65  of the connector cam  210  are trimmed to complete assembly of male connector  200 . 
       FIGS. 9-12  illustrate assembly of the female connector  100 . As shown in  FIG. 9 , a spring  20  is adhered to a dimple  12  of a flex circuit contact mount  10 . The flex circuit contact mount  10  can be machined or molded using various plastics forming processes. In one illustrative embodiment, flex circuit contact mount  10  is made of Ultem® 1000 plastic. The spring  20  may comprise an elastomeric tube, such as silicone rubber, or can be cylindrical, rectangular, or any other suitable geometry. Alternatively, the spring may be of any type of spring, such as a leaf spring, or may comprise multiple separate springs along the width and/or length of the flex circuit  30 . Alternatively, a separate spring  20  is not needed if contact carrier  62  is made of elastomer to act as a spring. Alternatively or additionally, cam contacts  64  themselves can be configured to act as a spring, obviating the need for a separate spring  20 . Alternatively or additionally, flex circuit contact mount  10  or the flex circuit  30  itself may be configured to provide the desired biasing properties, by geometry, material, or both, obviating the need for a separate spring  20 . For example, flex circuit  30  may have a bellows, pleated, or rippled geometry with contacts shaped to accommodate stretching of the overall flex circuit. For example, flex circuit  30  may comprise serpentine contacts on a stretchable substrate as taught in US Patent Application Publication 2009/0317639, which is incorporated herein by reference. As another example, flex circuit  30  may comprise a stretchable electronic device made according to one or more of the teachings of U.S. Pat. Nos. 7,557,367; 7,521,292; and 7,622,367; and US Patent Application Publications 2010/0002402 and 2010/0059863, which are incorporated herein by reference. 
     As shown in  FIG. 10 , flex circuit  30  comprising a plurality of flex circuit contacts  32  and  32 ′ is wrapped around the perimeter of flex circuit contact mount  10  and secured thereto to form female contact assembly  110  shown in  FIG. 11 . The flex circuit contacts are arranged to form at least one group of contacts spaced along the axis of the connector, with the axis being in the same direction as the arrow shown in  FIG. 11 . The flex circuit contacts may comprise two sets of axially-spaced, parallel, linear contacts, as illustrated. Note that in this illustrative embodiment, for each flex circuit contact  32  there is a corresponding contact  32 ′ that is radially spaced about the axis. Alternatively, the contacts may be arranged in other configurations having one or more groups of axially-spaced contacts, as will be described later with respect to  FIGS. 21A-23 , or having only radially-spaced contacts. This inventive connector lends itself to many different possibilities, including various layouts of the flex circuit contacts. Although the camming connector invention could be carried out without using a flex circuit, such as by using wire or other metal contacts affixed to a supporting structure, using flex circuit facilitates many different layouts of the contacts, permits consistent manufacturing tolerances for contact placement and alignment, and holds them reliably spaced with respect to each other, allowing many contacts to be used in a small space. The flex contacts may have different lengths, with the camming contacts engaging one flex contact before the rest, thereby allowing one contact, such as a ground, to be electrically connected before the rest. The contacts may even be positioned and configured such that the axial rotation allows contacts to be switched on and off in a particular order, with the cam contacts making and breaking contact with the flex circuit contacts as the connector is rotated. 
     The flex circuit  30  may comprise side tabs  34  and  34 ′ having cut outs  35  and  35 ′ formed therein for securing to a mounting post  18  on the flex circuit contact mount  10 . Although a single mounting post is illustrated, there may alternatively be a separate mounting post for each side tab  34  and  34 ′ at the ends of the flex circuit  30 . Alternatively, other attachment methods are possible. While flex circuit  30  is illustrated as having two side tabs  34  and  34 ′ whose flex circuits  32  and  32 ′ take right angle turns to terminal on a single center tab  36 , many other configurations are possible. The illustrative embodiment provides for two sets of contacts while requiring only a single feedthrough  122  ( FIG. 12 ) for center tab  36  to pass. 
     As shown in  FIG. 11 , a moisture barrier cap  120  is assembled onto female contact assembly  110  and adhered to it as shown in  FIG. 12 . The moisture barrier cap  120  can be machined or molded using various plastics forming processes. In an illustrative embodiment, the moisture barrier cap  120  is made of Ultem® 1000 plastic. 
     As shown in  FIG. 12 , the flex circuit contact feedthrough  122  of the female contact assembly  110  is sealed with epoxy  140  to complete assembly of female connector  100 . 
       FIG. 13  shows lock features of the female connector  100  (shown without the flex circuit and moisture barrier cap) and key features of the male connector  200 . The flex circuit contact mount  10  of the female connector has a keyway  14  formed therein, and the overmold  70  of the male connector has a matching key  72 . When the male and female connectors are oriented such that the key  72  is aligned with the keyway  14 , the connectors can be pushed together in the axial direction of the connectors, as indicated by the arrow. Once the parts have slid far enough so that the bottom  73  of the key  72  has traveled past the edge of the keyway  14 , the cam contacts  64  land on or near cam contact landings  17  on the inner surface of flex circuit contact mount  10 . When the connectors are have been thus pushed together, the sealing ring  220  of the male connector  200  is in sealing contact with an inner sealing surface  16  of the flex circuit contact mount  10  of the female connector, reliably sealing the connectors against moisture, and providing a frictional engagement with the inner sealing surface  16  to stabilize the connectors. The connectors can then be rotated with respect to each other such that the key and keyway are no longer aligned, locking them in place and preventing them from being pulled apart. As the connectors are rotated with respect to each other, as shown in  FIGS. 14 ,  15 , and  15 A, the cam contacts  64  and  64 ′ contact the flex circuit contacts  32  and  32 ′. The frictional engagement of the sealing ring  220  with the sealing surface  16  also prevents the connectors from inadvertently rotating with respect to each other. Thus, sealing, translational stabilization, translational locking, contact, and rotational stabilization are accomplished in one motion, simply by inserting the male connector into the female connector and twisting. Alternatively, detents, magnets and other methods of stabilizing the connector in rotation and translation are possible. 
     Alternatively, although not illustrated, cam contacts  64  on a first side of the male connector  200  may be differently shaped from cam contacts  64 ′ on the other side. The cam contact keyway  15  on one side of the flex circuit contact mount  10  may be shaped to allow cam contacts  64  but not cam contacts  64 ′ to slide through it. Additionally or alternatively, a cam contact keyway  15 ′ on the opposite side (shown in  FIG. 15A ) may be shaped to allow cam contacts  64 ′ but not cam contacts  64  to slide through it. This eliminates the need for a separate keyway  14  and key  72 . 
     Alternative sealing mechanisms to the sealing ring  220  may be used. For example, an elastomeric washer may be placed between the bottom of the flex circuit contact mount  10  and the mating surface of the male overmold  70 . This elastomeric washer is dimensioned to have an interference fit such that when the connectors are pushed against each other and rotated, the connectors frictionally engage the washer so that they cannot be inadvertently rotated apart. Although slightly longer to allow for the thickness of the washer, this washer-type seal allows the overall connector to be narrower than for the sealing ring type. 
       FIG. 14  shows the camming contact of the female connector  100  (shown without the moisture barrier cap) and the male connector  200 . The flex circuit  30  of the female connector  100  has multiple flex circuit contacts  32  and  32 ′, with six (three on each side) shown here for illustration purposes. The male contact assembly  60  has multiple fixed metal cam contacts  64  and  64 ′ for coupling to the flex circuit contacts  32  and  32 ′. Again, six, where on each side, are shown for illustration purposes and to correspond to the six flex circuit contacts. Optionally, insulating barriers may be provided between the flex circuit contacts or between the cam contacts, or both. These barriers may also aid in alignment of the contacts, and may be especially advantageous for high-contact count connections. These optional barriers may also be configured to provide added stabilization and prevent rotation that might tend to inadvertently disconnect the connectors. 
     Note that during the insertion of male connector  200  into female connector  100 , no part of the male connector contacts the flex circuit contacts  32 . This prevents damage to the flex circuit contacts  32  that might otherwise occur if a portion of the male connector, such as cam contacts  64 , were allowed to scrape against the flex circuit contacts  32  during insertion. It is not until the male connector is fully inserted into the female connector that they can rotate with respect to each other such that cam contacts  64  contact flex circuit contacts  32 . 
       FIGS. 15A and 15B  are top and side perspective views, respectively, of the multi-contact connector system  1000  with female connector  100  engaged and rotated in the direction of the arrow with respect to the male connector  200 . The moisture barrier cap is not shown. The cam contacts  64  are shown coupled to the flex circuit contacts  32  at two camming contact locations,  52  and  54 . The locations where the cam contacts  64  couple to the flex circuit contacts  32  change as the female connector  100  is rotated with respect to the male connector  200 . The spring  20  ensures that the flex circuit  30  remains in tight, stable electrical and mechanical connection with the cam contacts  64  at a wide range of degrees of rotation. 
       FIGS. 16 and 16A  show top and side cross sectional views, respectively, of the multi-contact connector system  1000  of the present invention, illustrating the sealing features for moisture proofing. The moisture barrier cap  120  has a flex circuit contact feedthrough  122  formed therein through which flex circuit  30  extends from the inside to the outside of the moisture barrier cap. The flex circuit contact feedthrough  122  is sealed with epoxy  140  to prevent moisture leakage therethrough. In addition, an adhesive seal  150  is formed between the moisture barrier cap  120  and the female flex circuit mount  10  to prevent moisture leakage at that junction. Furthermore, when the multi-contact connector system  1000  is fully assembled with the female connector  100  engaged with the male connector  200 , the sealing ring  220  of the male connector is in sealing contact with the inner sealing surface  16  of the flex circuit contact mount  10  of the female connector, thereby preventing moisture leakage to the cam contacts  64  and flex circuit contacts  32 . 
       FIGS. 17A and 17B  show side and front views of the female connector  100 . 
       FIGS. 18A and 18B  show side and front views of the male connector  200 . 
       FIGS. 19A and 19B  are side cross-sectional views illustrating the contact between the cam contacts  64  and the flex circuit contacts  32 .  FIG. 19A  shows the cam contacts  64  aligned with landings  17  on flex circuit  30 , but not yet rotated to contact the flex circuit contacts. Cam contacts  64  are shown as not perfectly aligned with each other, illustrating manufacturing variations that typically can be expected in real world parts. As shown in  FIG. 19B , flex circuit contacts  32  reliably make contact with cam contacts  64  because the flex circuit  30  conforms to the actual location of the cam contacts. This can be achieved in several ways. The flex circuit  30  is flexible and is put in tension around cam contacts  64 . Flexibility of the flex circuit  30  in the proximity of the contact site can be increased using a flex circuit slit  37  between neighboring cam contacts  64 , as shown in  FIG. 20 . Stress concentrations at both ends of each flex circuit slit  37  can be reduced using stress slit holes  38  in the shape of a circle, tear drop or alternative geometry. As described above, one way this tension may be maintained is by use of an elastomeric spring  20 , as shown in  FIGS. 15A and 15B . Alternatively, as described above, contact carrier  62  (shown in  FIG. 5 ) can be made of elastomer to create a compliant male contact assembly  60  ( FIG. 6 ), allowing it to act as a spring for keeping cam contacts  64  engaged with the flex circuit contacts  32 . Yet another way is as shown in  FIG. 20 , using a flexible adhesive  19 , such as RP Series 3M™ VHB™ Foam Tape, to join the two ends of the flex circuit  30  together and to act as a spring so that a separate spring  20  shown in  FIG. 14  is not needed. The minimum functional attributes of the flexible adhesive  19  is such that the bonding shear strength is sufficient to withstand tension in the flex circuit, and shear strain allows sufficient deflection of the flex circuit in assembly and use. The shear modulus of the flexible adhesive  19  will determine the tension in the flex circuit  30 . 
       FIGS. 21A and 22A  are simplified top views of an alternative embodiment of the present invention, showing portions of a male connector showing cam contacts  64  and a female connector showing flex circuit contacts  32 , wherein cam contacts  64  are aligned with landings  17  on flex circuit  30 , but not yet rotated to contact the flex circuit contacts. While the embodiment shown in  FIG. 15A  has two sets of cam contacts  64  and  64 ′ and two sets of flex circuit contacts  32  and  32 ′, that of  FIG. 21A  has three sets of each, and that of  FIG. 22A  has four sets of each. Alternatively, although not illustrated, the connectors may contain only one set or five or more sets of contacts. Furthermore, the number of contacts in each set is not limited. While most of the figures herein, such as  19 B, show two sets of three contacts in each set, each set may alternatively contain one, two, or more than three contacts, and also need not necessarily contain the same number of contacts in each set. Furthermore, the male connector need not contain the same number of contacts as the female contact. As an example, in a device requiring a connector with five contacts for various functions, to keep the structure symmetrical, two sets of three cam contacts  64  may be provided on the male connector, whereas the female connector may have only five flex circuit contacts  32 .  FIGS. 21B and 22B  show the connectors of  FIGS. 21A and 22A , respectively, with the male connector rotated with respect to the female connector such that the cam contacts  64  make electrical and mechanical contact with flex circuit contacts  32 . Note that the embodiments of  FIGS. 21A-21B  and  22 A- 22 B may be configured with only one contact per “set,” such that contacts are all radially spaced about the axis but not axially spaced, to provide a very low profile connector having three and four contacts, respectively, which would be sufficient for many applications. 
       FIG. 23  illustrates another alternative embodiment having only one set of cam contacts  64  and only one set of flex circuit contacts  32 . In this embodiment, the flex circuit  30  is held in tension around a flex circuit contact mount comprising several posts, such as circular posts  22  and elliptical post  23 . Flex circuit  30  may comprise material that is flexible due to geometry, material elasticity, or both, as described earlier, and be placed in tension around posts  22  and  23 ; alternatively one of the posts, such as post  23 , may comprise elastomeric material and act like spring  20  of previously-described embodiments. Contact assembly  60  is inserted with its cam contacts  64  alongside flex circuit contacts  32  of flex circuit  30  and then rotated as shown by the arrow to bring the cam contacts into contact with flex circuit contacts. Notice that in this embodiment, the connector bearing the cam contacts is inserted alongside, not interior to, the wrapped flex circuit. 
     In an alternative embodiment illustrated in  FIG. 24A-24D , male connector  400  includes a flex circuit  430 , held in tension by flex circuit carrier  410 , and an elastomeric spring  420  that tends to bias the male connector contacts  432  against the female connector contacts  364  on the female connector  300  when the connectors are in their operating orientation. The female connector  300  is relatively rigid and is noncircular. The male contacts  432  may be part of the flex circuit  430  or may be mounted on the circuit or other flexible plastic. A flange  414  may be keyed (not shown) to provide polarity and locking functions in a similar manner as the various keys described above.  FIG. 24D  shows the cam action of the male connector  400  as it is rotated clockwise with respect to the noncircular female connector  300  to make contact of the male connector contacts  432  with the female connector contacts  364 . It should be noted that in the illustrative embodiments thus far described, rotation of the one connector with respect to the other to cause camming engagement of the flex circuit causes additional tensile force to be applied to the flex circuit. 
     In yet another alternative embodiment illustrated in  FIG. 25A-25C , a male connector  600  comprises a flex circuit  630  surrounding a carrier  662  having one or more elastomeric springs  620  (two shown). The flex circuit  630  has flex circuit contacts  632  and is captured in a flex capture feature, which may be located in the carrier  662 . As shown in  FIGS. 25B and 25C , the male connector  600  is inserted into a rigid, noncircular female connector body having fixed contacts  564 , and then rotated to engage the male connector contacts  632  with the female connector contacts. It should be noted that for the embodiment in  FIG. 25A-25C  unlike in the illustrative embodiments described previously, rotation of the one connector with respect to the other to cause camming engagement of the flex circuit does not rely on the development of tensile force in the flex circuit. The contacts on the flex circuit  630  may be oriented as in some of the previously-described embodiments, such that they are axially spaced and parallel to each other, with traces that take a right angle so that they can be brought out from the connector on a tab  636  of the flex circuit through a feedthrough.  FIGS. 25B and 25C  illustrate two different shapes for the interior of the housing of the female connector  500 . In one embodiment, the interior is oval or elliptical. In a second illustrative embodiment, the shape allows rotation of the male connector in one direction only and has a positive stop to provide tactile feedback that the connector has been rotated into the operating position with the contacts engaged. The male connector  600  is inserted into the female connector  500  in an insertion orientation, and then rotated to an operating position in which the male contacts  632  contact the female contacts  564 . 
     Although not shown, the embodiments of  20 ,  21 A- 21 B,  22 A- 22 B,  23 ,  24 A- 24 D, and  25 A- 25 C may include the locking and sealing features shown and described for other embodiments. 
     While the connector of the present invention has been described in detail in the context of its application to a BTE sound processor for an implantable cochlear system, it is to be understood that a connector in accordance with the present invention also has utility to any application having similar requirements. For example, the present invention may be used for other medical devices, such as conventional BTE hearing aids, which have a similar problem of sweat adversely affecting the battery and electronics. The advances set forth herein may also be used outside the field of medical devices. For example, the present invention can be used for military and police applications, such as for personal communication devices. Rather than carry around cumbersome walkie-talkies, a simple external, ear-mounted device can be used, utilizing the multi-contact connector system of the present invention to connect batteries and accessories. The present invention may also be used for portable computer and Internet hand-held device systems, and for personal entertainment devices that require a seal protection and mechanical stability. Furthermore, for some applications, the connection need not be moisture resistant, thereby eliminating the need for some of the sealing features, such as the sealing ring and its attendant groove and sealing ring surface on the mating connector, and the moisture barrier cover and its attendant epoxy and adhesive seals, thereby allowing for a more compact and less expensive multi-contact connection system. Such non-moisture resistant applications may include, for example, non-ear-level (e.g., body-worn) sound processors. All of these other applications are intended to come within the scope of the present invention. 
     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.