Abstract:
An audio jack system includes a special audio jack adaptor that is particularly useful for digital players (e.g., cell phone, smartphone, MP3 player, computer, etc.) housed within watertight enclosures. When a headset is plugged directly into the digital player, the player&#39;s audio signal automatically goes to the headset, and the digital player&#39;s onboard speaker is silent. When nothing is plugged into the digital player, the audio signal automatically goes to the player&#39;s onboard speaker. When just the special adaptor is plugged into the player, the audio signal still goes to the onboard speaker; however, subsequently plugging the headset into the plugged-in special adaptor redirects the audio signal to the headset and not to the onboard speaker. To accomplish such results, a plug end of the adaptor includes a split-ring or split-tip set of open contacts that effectively close upon plugging the headset into a receptacle end of the adaptor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional patent application Ser. No. 61/571,788 filed on Jul. 5, 2011 by the present inventor. 
    
    
     FIELD OF THE INVENTION 
     The subject invention generally pertains to audio jacks and more specifically to audio jacks comprising a series of ring contacts disposed along a common centerline. 
     BACKGROUND 
     Audio jacks are often used for connecting headphones to audio players such as cell phones, digital music players, computers, etc. An audio jack, for example, might comprise a multi-contact plug on the headphones and a mating multi-contact receptacle on the audio player. Inserting the plug of the headphones into the player&#39;s mating receptacle may enable the player to transmit audio signals to the headphones. However, water leakage, player inaccessibility, and/or other problems can occur if the audio player is contained within a supposedly water-tight enclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an audio jack system according to at least one example of the invention. 
         FIG. 2  a schematic view of the audio jack system shown in  FIG. 1  but showing an example auxiliary sound unit (e.g., a conventional known headset) plugged into a conventional known digital player&#39;s audio socket. 
         FIG. 3  a schematic view of the audio jack system shown in  FIG. 1  but showing a special adaptor plugged into a digital player&#39;s audio socket. 
         FIG. 4  a schematic view similar to  FIG. 3  but showing the auxiliary sound unit plugged into the adaptor. 
         FIG. 5  is a cross-sectional view showing the auxiliary sound unit plugged into the player&#39;s audio socket. 
         FIG. 6  is a cross-sectional view showing the adaptor plugged into the player&#39;s audio socket. 
         FIG. 7  is a cross-sectional view showing the adaptor plugged into the player&#39;s audio socket and the auxiliary sound unit plugged into the adaptor. 
         FIG. 8  is a cross-sectional view showing the audio jack system of  FIG. 1 . 
         FIG. 9  is a cross-sectional view taken along line  9 - 9  of  FIG. 8 . 
         FIG. 10  is a cross-sectional view taken along line  10 - 10  of  FIG. 8 . 
         FIG. 11  is a cross-sectional view taken along line  11 - 11  of  FIG. 8 . 
         FIG. 12  is a cross-sectional view taken along line  12 - 12  of  FIG. 8 . 
         FIG. 13  is a cross-sectional view taken along line  13 - 13  of  FIG. 8 . 
         FIG. 14  is a cross-sectional view taken along line  14 - 14  of  FIG. 8 . 
         FIG. 15  is a cross-sectional view taken along line  15 - 15  of  FIG. 8 . 
         FIG. 16  is a cross-sectional view taken along line  16 - 16  of  FIG. 8 . 
         FIG. 17  is a cross-sectional view taken along line  17 - 17  of  FIG. 8 . 
         FIG. 18  is a cross-sectional view taken along line  18 - 18  of  FIG. 8 . 
         FIG. 19  is a partial top view taken along line  19 - 19  of  FIG. 8 . 
         FIG. 20  is a partial top view taken along line  20 - 20  of  FIG. 21 . 
         FIG. 21  is a front view of another example audio jack system. 
         FIG. 22  is a top view of  FIG. 23 . 
         FIG. 23  is a front view similar to  FIG. 21  but showing an example adaptor plugged into an example audio player. 
         FIG. 24  is a front view of an audio player being inserted into an example enclosure. 
         FIG. 25  is a front view similar to  FIG. 24  but showing the audio player sealed inside the enclosure. 
         FIG. 26  is a cross-sectional view similar to  FIG. 8  but showing an example audio jack system with an example adaptor that includes a switch, wherein the switch is schematically illustrated. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-19  illustrate an example of an audio jack system  12  and/or various portions thereof. In some examples, audio jack system  12  comprises a special adaptor  14  for coupling an auxiliary sound unit  16  to a conventional known digital player  18  in such a way that adaptor  14  is particularly useful when digital player  18  is contained within an optional water-tight enclosure  22 . 
     Depending on the selected connected or disconnected relationship of digital player  18 , auxiliary sound unit  16 , and adaptor  14 , player  18  operates in an onboard speaker mode ( FIGS. 1 ,  3 ,  6  and  8 ) or an auxiliary speaker mode ( FIGS. 2 ,  4 ,  5  and  7 ). In the onboard speaker mode, an electrical circuit  24  of digital player  18  conveys an audio signal  26   a  to an onboard speaker  28  of player  18  and not to an auxiliary speaker  32  of auxiliary sound unit  16 . In the auxiliary speaker mode, circuit  24  conveys an audio signal  26   b  to auxiliary speaker  32  and not to onboard speaker  28 . 
     Player  18  operates in the onboard speaker mode when neither an adaptor plug  20  of adaptor  14  nor an auxiliary plug  40  of auxiliary sound unit  16  are plugged into an audio socket  10  of player  18 , as shown in  FIGS. 1 and 8 . Player  18  also operates in the onboard speaker mode when adaptor plug  20  is plugged into audio socket  10  while auxiliary plug  40  is not plugged into an adaptor receptacle  30  of adaptor  14 , as shown in  FIGS. 3 and 6 . Player  18  operates in the auxiliary speaker mode when auxiliary plug  40  is plugged directly into audio socket  10 , as shown in  FIGS. 2 and 5 . Player  18  also operates in the onboard speaker mode when adaptor plug  20  is plugged into audio socket  10  while auxiliary plug  40  is plugged into adaptor receptacle  30 , as shown in  FIGS. 4 and 7 . 
     To further understand the operation and relationship of digital player  18 , adaptor  14  and auxiliary sound unit  16 , it should first be noted that each of them have compatible connectors, such as male plugs and/or female receptacles. Such male and/or female connectors are sometimes known as or examples of which include, but are not limited to, an audio jack, phone jack, jack plug, stereo plug, mini-jack, headphone jack, TS tip-sleeve connector, TRS tip-ring-sleeve connector, TRRS tip-ring-ring-sleeve connector, TRRRS tip-ring-ring-ring-sleeve connector, 3.5 mm audio jack, and 2.5 mm micro audio jack. 
     Auxiliary sound unit  16  is schematically illustrated to represent any known speaker device (e.g., earphones, headphones, headset, ear buds, desktop speakers, car speaker, etc.) with a known plug connector (e.g., audio jack, phone jack, jack plug, stereo plug, mini-jack, headphone jack, TS tip-sleeve connector, TRS tip-ring-sleeve connector, TRRS tip-ring-ring-sleeve connector, TRRRS tip-ring-ring-ring-sleeve connector, 3.5 mm audio jack, 2.5 mm micro audio jack, etc.). 
     Digital player  18  is schematically illustrated to represent any electronic device for generating an audio signal than can be converted to sound. Examples of digital player  18  include, but are not limited to, a telephone, digital music player, camera, camcorder, computer, tablet computer, laptop computer, personal digital assistant, video game player, GPS unit (global positioning system), IPHONE, IPOD, IPAD, MP3 player, etc. The terms, iPhone, iPod and iPad are registered trademarks of Apple, Inc. of Cupertino, Calif. Examples of digital device  18  include both portable and generally immobile devices. Some examples of a “telephone” include, but are not limited to, a cell phone, smartphone, satellite phone, etc. 
     Adaptor  14  is schematically illustrated to represent any electrical coupling comprising a male plug and a female receptacle that can couple auxiliary plug  40  to audio socket  10  and selectively configure player  18  to its onboard speaker mode and its auxiliary speaker mode via the four selective operative arrangements shown in  FIGS. 1-4 , which are also shown in  FIGS. 5-8 . 
     For sake of example, digital player  18 , auxiliary sound unit  16  and adaptor  14  will be described herein as having one or more TRRS connections; however, such connections (e.g., plug  20  and socket  10 ) can have more or less electrically conductive contacts (e.g., rings, sleeves, tabs, etc.) than that of just a TRRS plug or socket. The term “contact” when used as a noun, e.g., electrical contact, headset contact, auxiliary contact, inner adaptor contact, outer adaptor contact, and socket contact, means an electrically conductive surface being sufficiently exposed to touch in electrical continuity another exposed electrically conductive surface. 
     In some examples, audio socket  10  comprises a first socket contact  10   a , a second socket contact  10   b , a third socket contact  10   c , a fourth socket contact  10   d , and sometimes at least one other additional socket contact  10   e.    
     In some examples, adaptor plug  20  comprises a first outer adaptor contact  20   a , a second outer adaptor contact  20   b , a third outer adaptor contact  20   c , a fourth outer adaptor contact  20   d , and sometimes at least one other additional outer adaptor contact  20   e.    
     In some examples, adaptor receptacle  30  comprises a first inner adaptor contact  30   a , a second inner adaptor contact  30   b , a third inner adaptor contact  30   c , a fourth inner adaptor contact  30   d , and sometimes at least one other additional inner adaptor contact  30   e.    
     In some examples, auxiliary plug  40  comprises a first auxiliary contact  40   a , a second auxiliary contact  40   b , a third auxiliary contact  40   c , and sometimes at least one other additional auxiliary contact  40   d . Additional contacts, such as  10   e ,  20   e ,  30   e  and  40   d , are used in some examples as means for conveying various other signals, examples of which include, but are not limited to, stereo audio signals, microphone signals, video signals, etc. 
     Various examples of audio jack system  12  have their contacts  10   a - d ,  20   a - d ,  30   a - d  and  40   a - c  be of various structure, examples of which include, but are not limited to, a full 360-degree tip, ring or sleeve (e.g., contacts  20   a ,  20   b ,  20   e  and  40   a - c ); a partial tip, ring or sleeve less than 360-degrees (e.g., contacts  20   c  and  20   d ); part of a resiliently flexible electrically conductive tab (e.g., contacts  10   a - d  and  30   a - e ); and various combinations thereof. The term, “tip” generally refers to an outboard or distal end of a plug, the term, “sleeve” generally refers to an inboard end of a plug or socket, and the term, “ring” refers to an annular contact interposed between the inboard and outboard end of a plug or socket. 
     In some examples, digital player  18  comprises a housing  34  containing electrical circuit  24  and onboard speaker  28 . Electrical contacts  10   a - d  are spaced apart and electrically insulated from each other. Referring to  FIGS. 8 and 19 , in some examples, contacts  10   a - d  are distributed circumferentially about a longitudinal centerline  36  of audio socket  10  and certain audio socket contacts extend various longitudinal distances along audio socket  10  to become aligned with corresponding contacts of adaptor plug  20  and auxiliary plug  40  when those plugs are inserted into audio socket  10 . 
     To convey at least audio signal  26   b  to audio socket  10 , electrical lines  38  connect circuit  24  to socket contacts  10   a  and  10   b  and, in some examples, to one or more additional socket contacts  10   e . To convey an audio signal  26   a  to onboard speaker  28 , electrical lines  42  connect circuit  24  to onboard speaker  28 . When digital player  18  is turned on to produce sound  44 , circuit  24  selectively directs audio signal  26   a  or  26   b  to speaker  28  or  32  respectively. When something closes contacts  10   c  and  10   d  (i.e., connects the two in electrical continuity with each other), electrical lines  46  convey this information to circuit  24 , wherein circuit  24  responds by directing audio signal  26   b  through lines  38  to socket contacts  10   a  and  10   b  and does not direct audio signal  26   a  to online speaker  28 , whereby player  18  is configured in the auxiliary speaker mode, as shown in  FIGS. 2 ,  4 ,  5  and  7 . When nothing closes contacts  10   c  and  10   d , circuit  24  directs audio signal  26   a  through lines  42  to online speaker  28  and does not direct audio signal  26   b  to socket contacts  10   a  and  10   b , whereby player  18  is configured in the onboard speaker mode, as shown in  FIGS. 1 ,  3 ,  6  and  8 . 
     In some examples, the design of adaptor  14  and auxiliary sound unit  16  are such that inserting auxiliary plug  40  into audio socket  10  closes contacts  10   c  and  10   d  to configure player  18  in the auxiliary speaker mode; inserting adaptor plug  20  and auxiliary plug  40  into audio socket  10  and adaptor receptacle  30 , respectively, closes contacts  10   c  and  10   d  to configure player  18  in the auxiliary speaker mode; plugging neither adaptor plug  20  nor auxiliary plug  40  into audio socket  10  leaves contacts  10   c  and  10   d  open to configure player  18  in the onboard speaker mode; and plugging adaptor plug  20  into audio socket  10  while not plugging auxiliary plug  40  into adaptor receptacle  30  leaves contacts  10   c  and  10   d  open to configure player  18  in the onboard speaker mode. To accomplish such results, some examples of adaptor  14  and auxiliary sound unit  16  are structured as follows. 
     Referring to FIGS.  8  and  15 - 18 , in some examples, auxiliary contacts  40   a - d  are rings axially spaced apart and disposed on a generally non-electrically conductive core  48  (e.g., made of plastic) such that contacts  40   a - d  are electrically insulated (electrically isolated) from each other. Wires  50   a ,  50   b  and  50   d  (plurality of wires) connect auxiliary contacts  40   a ,  40   b  and  40   d  of auxiliary plug  40  to at least one auxiliary speaker  32 . When auxiliary plug  40  is plugged directly into audio socket  10 , or when auxiliary plug  40  is plugged into adaptor receptacle  30  and adaptor plug  20  is plugged into audio socket  10 , wires  50   a ,  50   b  and  50   d  convey audio signal  26   b  to at least one auxiliary speaker  32 . 
     Referring to FIGS.  8  and  10 - 13 , in some examples of adaptor plug  14 , outer adaptor contacts  20   a ,  20   b  and  20   e  are rings axially spaced apart and disposed on a generally non-electrically conductive core  52  (e.g., made of plastic) such that contacts  20   a ,  20   b  and  20   e  are electrically insulated from each other. Contacts  20   a ,  20   b  and  20   e  are centrally disposed around a longitudinal centerline  54  of adaptor plug  20 . Contacts  20   c  and  20   d  are circumferentially spaced apart from each other and extend less than the full circumferential distance around adaptor plug  20 . Contacts  20   c  and  20   d  are electrically isolated from contacts  20   a ,  20   b  and  20   e . Contacts  20   c  and  20   d  are longitudinally aligned and are equally spaced radially on opposite sides of centerline  54  (contacts  20   c  and  20   d  are substantially equidistant from centerline  54 ). When auxiliary plug  40  is not plugged into adaptor receptacle  30 , contacts  20   c  and  20   d  are electrically isolated from each other. 
     Referring to  FIGS. 8 ,  9  and  14 , in some examples of adaptor  14  and adaptor receptacle  30 , inner adaptor contacts  30   a - e  are spaced apart, and a housing  56  that is generally electrically non-conductive (e.g., made of plastic) electrically insulates contacts  30   a - e  from each other. In some examples, contacts  30   a - e  are distributed circumferentially about a longitudinal centerline  58  of adaptor receptacle  30  and certain adaptor receptacle contacts extend various longitudinal distances along adaptor receptacle  30  to become aligned with and engage corresponding contacts of auxiliary plug  40  when auxiliary plug  40  is inserted into adaptor receptacle  30 . For example, when auxiliary plug  40  is plugged into adaptor receptacle  30 , auxiliary contact  40   d  engages inner adaptor contact  30   e , auxiliary contact  40   a  engages inner adaptor contact  30   a , auxiliary contact  40   b  engages inner adaptor contact  30   b , and auxiliary contact  40   c  engages both inner adaptor contacts  30   c  and  30   d.    
     Likewise, when auxiliary plug  40  is plugged into audio socket  10 , auxiliary contact  40   d  engages socket contact  30   e , auxiliary contact  40   a  engages socket contact  30   a , auxiliary contact  40   b  engages socket contact  30   b , and auxiliary contact  40   c  engages both socket contacts  30   c  and  30   d . Similarly, when adaptor plug  20  is plugged into audio socket  10 , outer adaptor contact  20   e  engages socket contact  10   e , outer adaptor contact  20   a  engages socket contact  10   a , outer adaptor contact  20   b  engages socket contact  10   b , outer adaptor contact  20   c  engages socket contact  10   c , and outer adaptor contact  20   d  engages socket contact  10   d.    
     Regarding further details of adaptor  14 , a first conductor  60   a  electrically connects contact  20   a  to contact  30   a  (i.e., establishes electrical continuity between contacts  20   a  and  30   a ), a second conductor  60   b  electrically connects contact  20   b  to contact  30   b , a third conductor  60   c  electrically connects contact  20   c  to contact  30   c , and a fourth conductor  60   d  electrically connects contact  20   d  to contact  30   d . In some examples, a fifth conductor  60   e  electrically connects contact  20   e  to contact  30   e . Conductors  60   a - e  are schematically illustrated to represent any means for conveying electricity from one contact to another (same is true for so-called wires  50   a ,  50   b  and  50   d ). Examples of such conductors include, but are not limited to, wires, ribbons (e.g., see U.S. Pat. No. 7,927,151), bars, electrically conductive concentric cylinders (e.g., see U.S. Pat. Nos. 6,439,933; 7,404,734 or 7,950,967), and various combinations thereof. In some examples, such as the adaptors shown in  FIGS. 1-25 , the adaptors generally have no moving parts other than inherent flexibility of their component parts. 
     In the example illustrated in  FIGS. 1-19 , inserting auxiliary plug  40  into audio socket  10  engages auxiliary contact  40   c  with socket contacts  10   c  and  10   d , thereby closing contacts  10   c  and  10   d  to configure player  18  in the auxiliary speaker mode, as shown in  FIGS. 2 and 5 . 
     Alternatively, inserting adaptor plug  20  and auxiliary plug  40  into audio socket  10  and adaptor receptacle  30 , respectively, engages outer adaptor contact  20   c  with socket contact  10   c , engages outer adaptor contact  20   d  with socket contact  10   d , and engages auxiliary contact  40   c  with both inner adaptor contacts  20   c  and  20   d . This closes contacts  10   c  and  10   d  because electrical continuity is established from socket contact  10   c , through outer adaptor contact  20   c , through conductor  60   c , through inner adaptor contact  30   c , through auxiliary contact  40   c , through inner adaptor contact  30   d , through conductor  60   d , and to socket contact  10   d . Closing socket contacts  10   c  and  10   d  in this manner configures player  18  in the auxiliary speaker mode, as shown in  FIGS. 4 and 7 . 
     Although illustrated examples of audio jack system  12  show various contacts at certain axial positions, other examples of system  12  have different axial arrangements of the contacts. In some examples, contacts  10   c  and  10   d , contacts  20   c  and  20   d , contacts  30   c  and  30   d , and contact  40   c  are at other axial locations along their respective plug, socket or receptacle; however, their axial alignment with their corresponding contacts of engagement is maintained. 
     In another example, shown in  FIGS. 20-23 , an audio jack system  12 ′ comprises a digital player  18 ′, an adaptor  14 ′, and a limited rotation feature  62 . In this example, conductors  60   a - d  are supported by an elbow  64  that connects adaptor plug  20  to adaptor receptacle  10 . Limited rotation feature  62  provides, about centerline  54 , a limited range of relative rotation between adaptor plug  20  and audio socket  10  when adaptor plug  20  is disposed within socket  10 , as shown in  FIGS. 22 and 23 . In some examples, limited rotation feature  62  comprises a protrusion  66  on player  18 ′ and a mating flange  68  on adaptor  14 ′. When adaptor plug  20  is properly plugged into socket  10 , as shown in  FIGS. 22 and 23 , protrusion  66  provides flange  68  with an obstruction that limits the plug&#39;s rotation within socket  10 . Thus, feature  62  ensures proper rotational alignment of outer adaptor contacts  20   c  and  20   d  with corresponding socket contacts  10   c  and  10   d . It should be noted that feature  60  is schematically illustrated to represent countless means for ensuring proper rotational alignment between adaptor plug  20  and audio socket  10 . 
       FIGS. 24 and 25 , for instance, show a limited rotation feature  62 ′ provided by an adaptor  14 ″ being rotationally fixed relative to an enclosure  70  (e.g., watertight enclosure  22  of  FIG. 1 ). In some examples, enclosure  70  defines an interior  72  and an exterior  74  that are substantially hermetically isolated from each other when enclosure  70  is closed, as shown in  FIG. 25 . Thus, when player  18  is contained within the enclosure&#39;s interior  72  and auxiliary plug  40  is plugged into adaptor receptacle  30 , player  18  is substantially hermetically isolated from auxiliary sound unit  16 . The term, “hermetically isolated” means that liquid water is substantially blocked against appreciable leakage when subjected to a pressure differential of about 0.01 kg/cm 2 . In the illustrated example, adaptor plug  20  extends into the enclosure&#39;s interior  72 , and adaptor receptacle  30  is exposed to the enclosure&#39;s exterior environment  74 .  FIG. 24  shows player  18  being installed inside enclosure  70 , and  FIG. 25  shows player  18  properly installed within enclosure  70 . Arrows  76  and  78  of  FIG. 24  represent hermetically sealing digital player  18  and adaptor plug  20  within interior  72  of enclosure  70  while exposing adaptor receptacle  30  and auxiliary sound unit  16  to the enclosure&#39;s exterior environment  74 . In this example, enclosure  70  is of a shape that guides digital player  18  along a certain path that ensures that audio socket  10  of player  18  properly docks with adaptor plug  20 , such that socket contacts  10   c  and  10   d  are in proper rotational alignment and axial alignment with outer adaptor contacts  20   c  and  20   d.    
     In examples where there is limited relative rotation between adaptor plug  20  and the player&#39;s audio socket  10 , as illustrated in  FIGS. 20-25 , there exists between auxiliary plug  40  and adaptor receptacle  30  a 360-degree range of relative rotation about a second longitudinal centerline (e.g., a centerline  82  and  84 ) when auxiliary plug  40  is disposed within the adaptor receptacle  30 . Arrow  80  of  FIG. 23  illustrates allowing generally unrestricted relative rotation between auxiliary plug  40  and adaptor receptacle  30  about centerline  82 . Such freedom of rotation not only makes it easier to insert auxiliary plug  40  into adaptor receptacle  30  but also helps prevent the wires of auxiliary sound unit  16  from getting twisted or tangled. 
       FIG. 26  shows an example audio jack system  12 ′ wherein an adaptor  14 ′ includes a switch  86  operatively connected or wired to conductors  60   c  and  60   d  of adaptor  14 ′.  FIG. 26  shows switch  86  being selectively moveable to an open position (solid line) and a closed position (dashed line). In the closed position, switch  86  establishes electrical continuity between conductors  60   c  and  60   d  as an alternative to contact  40   c  serving that function. Thus, switch  86  and contact  40   c  are examples of an electrical shunt that when closed and engaged provide electrical continuity that inherently establishes and maintains substantially zero voltage potential across the set of contacts  10   c  and  10   d  (via plug  40  or  20 ′ being plugged into socket  10 ). In the open position, switch  86  breaks electrical continuity (providing electrical discontinuity) between conductors  60   c  and  60   d . With the addition of switch  86 , in some examples of adaptor  14 ′, contacts  30   c  and  30   d  are omitted. 
     Consequently, regardless of whether the auxiliary plug  40  is in engagement with adaptor receptacle  30 ′ or is spaced apart from adaptor receptacle  30 ′, digital player  18  is configured in the onboard speaker mode conveying audio signal  26   a  to onboard speaker  28  and not to auxiliary speaker  32  when adaptor plug  20 ′ is in engagement with audio socket  10  and switch  86  is in the open position. Also, regardless of whether switch  86  is in the open position or in the closed position, digital player  18  is configured in the onboard speaker mode conveying audio signal  26   a  to onboard speaker  28  and not to auxiliary speaker  32  when adaptor plug  20 ′ is in disengagement with audio socket  10  and auxiliary plug  40  is spaced apart from the audio socket. Further, digital player  18  is configured in the auxiliary speaker mode conveying audio signal  26   b  to auxiliary speaker  32  and not to onboard speaker  28  when adaptor plug  20 ′ is in audio socket  10 , switch  86  is in the closed position, and auxiliary plug  40  is in engagement with adaptor receptacle  30 ′. 
     Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those of ordinary skill in the art. The scope of the invention, therefore, is to be determined by reference to the following claims: