Abstract:
A universal serial bus receptacle for receiving a universal serial bus plug is disclosed. The receptacle utilizes an inner casing similar to a typical universal serial bus receptacle and an outer casing mounted around the inner casing to provide supporting structure to resist vibrational or other forces so that vibrational movement of the plug within the receptacle is reduced or prevented. This serves to reduce wear between the contact leads of the receptacle and the plug, making the receptacle suitable for long-term installation in a high-vibration environment such as an automobile. The supporting structure is preferably a pair of dual-leaf springs mounted on both side of the receptacle to provide a counter-balance to any tilting or deflection by the plug when received in the receptacle, the dual-leaf springs contact the plug in both fore and aft positions on both sides of the plug.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/873,166, filed Dec. 5, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to connectors for universal serial bus (USB) plugs and, in particular, to a USB assembly that reduces vibration effects on the electrical connections between a USB plug and a USB receptacle. 
       BACKGROUND 
       [0003]    Universal serial bus (USB) devices are defined by a standard including both a USB plug and a USB receptacle for receiving and electrically connecting with the USB plug. There are many designs for USB devices, as the standard is focused on a relatively narrow set of aspects of the devices. Specifically, the standard provides that certain aspects are required, such as the position of contact leads, a signal name for the contacts, contact wiring assignments, and some of the dimensional aspects of the devices, while others are references that may vary from manufacturer to manufacturer. 
         [0004]    Outside of mating geometry between the plug and the receptacle connection cases and lead positions, the dimensional aspects of the standards are somewhat open-ended. Generally speaking, the USB connection and devices provide an easy to use yet robust device. The USB devices provide a slip-fit connection that is easier to use and less fragile than, for instance, a pin connection. In fact, the use of the USB devices is facilitated by loose tolerances and fit between the plug and the receptacle. The loose tolerances are compensated for by using biased cantilever receptacle contacts, and using biased cantilever arms received in side openings of the plug to retain the plug in the receptacle. 
         [0005]    In greater detail, the USB plug is received in the USB receptacle rather easily, the entry of the plug deflecting biased cantilevers of the receptacle outwardly to permit receipt of the plug therein. The plug terminal or connecting end has a rectangular sheath or casing, with major and minor dimensions, defining an interior with a base or substrate having a first side in abutment with an interior surface of the sheath and a second, opposite side adjacent a generally empty cavity within the sheath. The second side of the substrate includes plug contacts or leads thereon facing into the cavity. Both the substrate and cavity are generally oriented, or aligned, with the major dimension of the sheath. 
         [0006]    The plug is inserted into a similarly rectangularly shaped sheath of the receptacle. The receptacle sheath defines an interior cavity that, according to the standard, is toleranced to be 0.41 mm to 0.21 mm larger than the plug sheath in the direction of the minor dimension, and is toleranced to permit a maximum of 0.7 mm larger in the major dimension direction. 
         [0007]    The relatively large dimensional differences between the plug and the receptacle allow for easy insertion, and retention structure is provided to assist in maintaining the plug and receptacle in a proper electrically connected relationship. As defined by the standard, the plug sheath includes four openings, two of which are each located on the major dimensional sides of the sheath. Cooperating with these openings are spring cantilever retainers extending inwardly into the interior of the receptacle, the cantilevers having a chamfered or angled end so that entry of the plug sheath deflects the cantilevers outward until an elbow formed at the base of the chamfer aligns with and is biased into the plug sheath openings. The spring bias of the cantilevers serve somewhat to hold the plug therebetween, and the cantilevers and plug sheath also provide a ground or shield/drain wire for the plug and receptacle. 
         [0008]    The relatively light constraint provided by the cantilevers generally presents few issues for most USB applications. The receptacle leads, as noted above, are cantilevered like the retention cantilevers, and the receptacle leads are also formed with a elbow leading to an angled ramp end or chamfer. As the plug enters the receptacle, the substrate deflects the ramp end of the receptacle leads outward, and the bias of the receptacle leads forces the elbow into contact with the substrate and the plug leads thereon. 
         [0009]    For most USB applications, the only connection issue between the plug and the receptacle is wear between the receptacle leads and the plug leads. More specifically, insertion and removal of the plug from the receptacle results in wear between the elbow of the receptacle leads and the plug leads. These leads are generally plated to improve electrical conductivity with gold, for instance, but have an underlying base metal that is much more susceptible to oxidation. What occurs, therefore, is known as fretting corrosion where the oxidation-resistant plating material wears away to expose a base that is, comparatively speaking, oxidation-prone. In respect to this possibility, the USB standard requires a minimum of 1500 plug insertions. When using USB devices with, for instance, a generally stationary computer or the like, such a minimum is likely adequate. 
         [0010]    However, for certain applications the wear resistance for a standard USB connection is not sufficient. As an example, one of the applications seeking to accommodate the immense popularity in music-playing devices such as MP3 players is providing in-dash connectivity with vehicles such as automobiles. In the past, automobile connectivity with portable music devices relied on a cassette-tape deck and on a device for connecting a line-out port on the music device (such as a portable CD-player or an MP3 player) with the cassette deck. However, cassettes have already become outmoded, and it appears as though compact discs are well on their way to being supplanted by non-tangible purchase means such as downloading music. The automobile industry realizes that, eventually, there will be greater demand for connecting a portable music device directing into an automobile for playing music than for inserting record-industry manufactured and distributed CDs and cassettes. 
         [0011]    Use of USB connectors in an automobile presents at least one very specific issue: vibration. Vibration of a dashboard in an automobile comes from many things, including road conditions, the running of the vehicle motor and other under-the-hood components, and the mating of brake components. Passengers in a vehicle are usually aware of vibration only when the amount seems out of the ordinary, but one need only watch the surface of liquid of a drink in a cup-holder to recognize the vibrational effects coursing through the vehicle. 
         [0012]    For the USB connection, it should be realized that the terminal end is only received in the receptacle by less than 1 cm. For a series “A” plug (for a commonly-carried USB “drive”), the entire plug is generally over 6 cm, while a series “B” plug is upwards of 3 cm and includes a cable or cord extending therefrom for connection to a portable device. The result of this is that the plug body (as well as any cable connected thereto) produces a moment force around the connection ends, and the plug bounces in response to automobile vibration. 
         [0013]    While this bounce is generally not significant enough for a vehicular passenger to even notice, it has significant effects on the connection leads between the plug and the receptacle. First of all, were the vibration significant enough that the leads were to actually come out of contact during data transmission, the control processors for the automobile audio system or the device connected with the receptacle may register an error (the interruption being interpreted as device removal), and/or music being played may skip, for instance. While these are generally nuisances or minor performance problems, a greater concern is the leads themselves. 
         [0014]    The leads, as discussed above, include the receptacle leads having an elbow biased into the plug leads. As the plug bounces due to vibration, there is constant wear on the elbow surface and the corresponding contact area on the plug leads. As the standard for USB connections requires only 1500 insertions, discussed above, the plating on the leads is generally insufficient to withstand such wear. The result is the above-discussed fretting corrosion where the underlying base metal oxidizes, preventing or inhibiting signal current. Eventually, the in-dash receptacle may become useless, and opening the dashboard to repair/replace such receptacle would be time consuming and laborious. While one may simply select metals for the base of the leads that are more robust or less prone to oxidation such as gold or stainless steel, such solutions may dramatically increase the cost of using the USB devices. 
         [0015]    Another issue attendant to the vibration is the fragility of solder connections. The USB receptacle is generally mounted on a printed circuit board (PCB). As the plug body bounces within the receptacle, this bouncing is at least partially transmitted through to the solder connections between the receptacle and the PCB. As is well-known, solder connections are poor under cyclic stress. Accordingly, the bouncing of the plug results in repeated stress at the solder joints and, hence, breaks the electrical connections between the receptacle and the PCB. 
         [0016]    Accordingly, there has been a need for an improved connection between USB plugs and receptacles for applications, particularly those which experience vibrational forces. 
       SUMMARY 
       [0017]    In accordance with an aspect, a universal serial bus receptacle is disclosed including a supporting structure for contacting a universal serial bus plug when received therein, the supporting structure providing bias to oppose deflection of the plug within the receptacle. 
         [0018]    In some forms, the supporting structure includes a plurality of bias structures that cooperate to balance force applied by each bias structure against the plug within the receptacle. The supporting structure may include a first bias structure and a second bias structure, each of the first and second bias structures providing respective forces in opposite directions. The first bias structure may provide a force around a pivot point in a first direction, while the second bias structure may provide a force around the pivot point in a second direction opposite the first direction. The first and second bias structures may be formed integral as a dual-leaf spring. 
         [0019]    In some forms, when the plug is received within the receptacle, the first bias structure contacts the plug in an aft position, and a second bias structure contacts the plug in a fore position. The supporting structure may further include a third bias structure for contacting the plug in a second aft position, and a fourth bias structure for contacting the plug in a second fore position, wherein the bias structures dynamically balance the sum of forces therefrom around the pivot point. The bias structures may be formed as a pair of dual-leaf springs. 
         [0020]    In some forms, the receptacle may further include an inner casing for receiving the plug therein, the inner casing may include a set of openings for the supporting structure, the supporting structure may include at least two bias structures providing forces in opposite directions to oppose deflection of the plug received within the inner casing, and the bias structures may at least partially pass through the inner casing openings to contact the plug received therewithin. The set of openings may include first and second aft openings in opposed sides of the inner casing, and first and second fore openings in the opposed sides of the inner casing, each of the fore and aft openings receiving bias structure to permit the bias structures to contact the plug when received within the inner casing. The receptacle may further include an outer casing for mounting and positioning the bias structures with at least a portion of the bias structures extending through the inner casing openings to contact and provide bias to the plug when received therein. The bias structures may provide a counter-balanced force with respect to each other against the plug when received therein. 
         [0021]    In some forms, the receptacle may further include cantilever retaining arms having at least a portion receivable within plug openings to assist in retaining the plug in the receptacle, wherein the supporting structure includes bias structures positioned to contact and provide bias force in opposite directions around a pivot point generally defined by the retaining arms and plug openings. 
         [0022]    In some forms, the supporting structure may include a first dual-leaf spring adapted to contact a first side of the plug when received in the receptacle in fore and aft positions, and a second dual-leaf spring adapted to contact a second side of the plug in fore and aft positions. The receptacle may further include cantilever retaining arms having at least a portion receivable within plug openings to assist in retaining the plug in the receptacle. The receptacle may further include an inner casing for receiving the plug therein, the cantilever arms formed integral with the inner casing, and an outer casing mounted around the inner casing, the outer casing providing a mount for the supporting structure. The inner casing may include openings to permit the support structure to pass at least partially therethrough to contact the plug when received within the receptacle. 
         [0023]    In some forms, the deflection is the result of vibrational forces, and the supporting structure opposes the vibrational forces. The receptacle may be mountable in an automobile, and the supporting structure opposes vibrational forces due to operation of the automobile. 
         [0024]    In some forms, the receptacle further includes an inner casing for receiving the plug therein, and an outer casing maintaining the supporting structure in contact with the plug when received within the receptacle, the outer casing serving to reduce vibrational stress on solder joints between the receptacle and a structure to which the receptacle is mounted. 
         [0025]    In some forms, the supporting structure includes bias structures adapted to contact major dimension sides of the plug, and includes bias structures for contacting minor dimension sides of the plug when received therein. The receptacle may further include an inner casing formed integral with the bias structures for contacting the minor dimension sides of the plug when received therein. The receptacle may further include cantilever retaining arms having at least a portion receivable within plug openings to assist in retaining the plug in the receptacle, wherein the retaining arms are formed integral with the inner casing and with the bias structures for contacting the minor dimension sides of the plug when received therein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    In the Figures,  FIG. 1  is a cross-sectional view of a universal serial bus (USB) connection including a typical USB plug in accordance with USB standards such as either standard series “A” or series “B” and mated within a USB receptacle in accordance with USB standards and further having a supporting structure in contact with the USB plug when received within the USB receptacle to reduce and impede movement of the USB plug within the USB receptacle; 
           [0027]      FIG. 2  is a cross-sectional view taken along the line  2 - 2  of  FIG. 4  showing an inner casing of the USB receptacle of  FIG. 1  and structure therein, and the USB plug of  FIG. 1  received within the USB receptacle; 
           [0028]      FIG. 3  is an elevational view of a USB receptacle of the PRIOR ART having the USB plug received therein; 
           [0029]      FIG. 4  is an elevational view similar to  FIG. 3  showing the inner casing of the USB receptacle of  FIG. 2  having the USB plug received therein and having an extended length in comparison to the USB receptacle of the PRIOR ART in  FIG. 3 ; 
           [0030]      FIG. 5  is a second elevational view of the inner casing of  FIG. 2  showing side finger-like supporting structure formed on a portion of the inner casing for contacting the USB plug when received therein to reduce or impede movement of the USB plug; 
           [0031]      FIG. 6  is a third elevational view of the inner casing of  FIG. 3  showing interior structure thereof including receptacle leads, the side finger-like supporting structure of  FIG. 5 , and retainers for restricting or impeding withdrawal of the USB plug from the receptacle; 
           [0032]      FIG. 7  is an elevational view of the USB receptacle, the view similar to the view of  FIG. 6  showing the outer casing secured around the inner casing of  FIG. 3 ; 
           [0033]      FIG. 8  is an second elevational view taken along the line  8 - 8  of the USB receptacle of  FIG. 7  with the USB receptacle secured with a printed circuit board; 
           [0034]      FIG. 9  is an elevational view of one halve of the outer casing of  FIG. 7 , the halve, in a recess thereof, supporting structure for impeding movement of the USB plug when received within the receptacle; 
           [0035]      FIG. 10  is a second elevational view taken along the line  10 - 10  of  FIG. 9  showing the halve having supporting structure mounted or positioned within the recess; 
           [0036]      FIG. 11  is a cross-sectional view of the halve and supporting structure taken along the line of  11 - 11  of  FIG. 10 ; 
           [0037]      FIG. 12  is an elevational view identical to  FIG. 1 ; 
           [0038]      FIG. 13  is an elevational view similar to  FIG. 7  showing a second form of a USB receptacle having an enlarged base portion for securing with a printed circuit board; and 
           [0039]      FIG. 14  is an elevational view of the USB receptacle of  FIG. 13  taken through the line  14 - 14  of  FIG. 13 . 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    Referring initially to  FIG. 1 , a USB receptacle  10  for resisting vibration and movement of any standard USB plug  12  is depicted. Towards this end, the receptacle  10  includes an outer casing  14  positioned around an inner casing  16 , the outer casing  14  including supporting structure  18  for reducing the mobility of the plug  12  within the receptacle  10 . The supporting structure  18 , thus, serves to reduce the movement of leads  20  of the plug  12  relative to leads  22  of the receptacle  10 . 
         [0041]    Generally speaking, the plug  12  is standardized and meets the series “A” or series “B” definitions. As described in the background, the standard plug  12  includes a terminal or connection end  30  including a generally rectangular sheath  32  having a major dimension  34  ( FIGS. 3 and 4 ) and a minor dimension  36 . Aligned with the sheath major dimension  34  and positioned to one side within the sheath  32  is a substrate  38  having a relatively small substrate minor dimension  40  aligned with the sheath minor dimension  36 . The substrate  38  has a first side  42  positioned against or close to an interior surface  44  of the sheath  32 , aligned with the sheath major dimension  34 , so that a substrate second side  46  opposite the first side  42  thereof defines a cavity  48  between the substrate second side  46  and a second sheath interior surface  50  that is opposite the interior surface  44 . Plug leads  20  are positioned on the substrate second side  46  that are accessible within the cavity  48 . Generally, the substrate is a non-conductive material, the leads  20 ,  22  are electrically conductive and electrically communicate with each other, and the sheath  32  is in electrical communication with the inner casing  16  to provide a shield or drain wire. 
         [0042]    The plug sheath  32  has first and second sides  60  and  62  that respectively include the interior surfaces  44  and  50 . As best seen in  FIGS. 2-4 , each side  60 ,  62  includes two openings  64 , generally defined by the USB standard, for receiving leaf spring retainers  66  of the receptacle  10 , as also defined by the USB standard. 
         [0043]    The receptacle  10  is in accordance with a series “A” standard USB receptacle, for instance. Specifically, dimensional requirements of the receptacle  10  that relate to receiving the plug  12  conform to the USB standard, as do wiring protocols, etc. The principal modifications of the receptacle  10 , in comparison to a common or typical USB receptacle that is also within the USB standard, the present receptacle  10  includes an outer casing  14  with the supporting structure  18 , and an extended length for the receptacle  10  including the inner casing  16  which would otherwise correspond to a receptacle body RB in a prior art USB, illustrated in  FIG. 3 . Each of the novel modifications will be described herein. 
         [0044]    Accordingly, the receptacle inner casing  16  and components therein need not significantly deviate from the USB standard. The inner casing  16  defines a cavity  68  (see, e.g.,  FIG. 6 ) for receiving the plug connection end  30 . The receptacle  10  includes the leads  22  aligned in accordance with the USB standard to mate with and contact the plug leads  20  when the plug  12  is received within the receptacle cavity  68 . The receptacle leads  22  are generally cantilevers having a base portion  72  mounted in and extending from a boot  74 , a first elbow portion  76  angled inwardly towards the cavity  68  or with respect to a longitudinal axis  78  of the receptacle  10 . The first elbow portion  76  is joined with a second elbow portion  77  angled outwardly with respect to the receptacle axis  78  to form a contact area  79 , and the leads  22  terminate with a tip  80 . 
         [0045]    The receptacle leads  22  are mounted so that the base portion  72  is generally positioned to one side of the receptacle axis  78 . As the plug sheath  32  is inserted into the receptacle inner casing  16  for electrical connection between the plug  12  and the receptacle  10 , a lead edge  90  of the plug substrate  38  contacts the second elbow portions  77  of each receptacle lead  22 , at a point in-board from the lead tip  80 , to deflect the receptacle leads  22  outward (away from the receptacle axis  78  and towards a side of the cavity  68 ). The receptacle leads  22  have a natural elasticity to impart a bias force to direct the receptacle lead  22  into the substrate  38  so that the lead contact areas  79  are against the plug leads  20  for electrical communication between the leads  22 ,  20 . 
         [0046]    In accordance with the USB standard, the inner casing  16  includes the above-mentioned leaf spring retainers  66  received in the plug openings  64 . The leaf spring retainers  66  are formed from side portions  16   a  of the inner casing  16 , the side portions  16   a  being sides aligned with the major dimension  34  of the plug  12  when connected therewith, and openings  88  being cut through the inner casing side portions  16   a  to define the retainers  66 . The resulting portion of the inner casing  16  for the retainers  66  is then shaped (such as by stamping) so that the retainers  66  are angled inwardly towards the receptacle axis  78  at a base portion  92 , and so that the retainers  66  have an elbow  94  formed thereon, as can be seen in  FIG. 2 . 
         [0047]    As the plug  12  is inserted into the receptacle  10 , the plug sheath  32  contacts a lead side  94   a  on the retainer elbows  94  to deflect the elbows  94  outwardly (away from the receptacle axis  78 ). Once the plug  12  has been inserted to a sufficient depth or extent, the elbows  94  become aligned with and resiliently move towards their natural position so that the elbows  94  are received within the plug openings  64  with an elbow trailing side  94   b  contacting a forward edge  64   a  of the openings  64 . This allows the elbows  94  to somewhat hook with and onto the plug  12  and hook onto the plug openings  64 . 
         [0048]    The purpose of the leaf spring retainers  66  in basic USB applications is to resist withdrawal of the plug  12  from the receptacle  10 . Towards this end, little attention was paid to details of the leaf spring retainers  66 . In an aspect of the present invention, the leaf spring retainers  66  are made more robust to resist vibrational forces. To accomplish this, the base portion  92  is widened at its connection line  92   a  ( FIG. 4 ) with the inner casing  16 , and the extent of the contact between the opening edge  64   a  with the elbow trailing side  94   b  is also widened. This allows for a stiffer spring bias (higher spring constant) for the retainers  66 , and greater resistance to fatigue, without having to increase the angle of inward deflection for the retainers  66  relative to the inner casing  16 . 
         [0049]    It should also be noted that, for typical USB connections, leaf spring retainers generally only resist withdrawal of the plug from the receptacle. In typical USB design, with the leaf spring retainers received in the plug openings, there is still significant play. That is, the plug can manually be moved into, out of, and around within the receptacle without significant resistance from typical retainers. In the present form, tolerances are preferably controlled for the leaf spring retainers  66  and plug openings  64  so that the spring retainers  66  serve to keep the plug  10  closely drawn into the receptacle  12  approximately, though not necessarily achieving, a snap-fit. 
         [0050]    To increase the benefit of the supporting structure  18  within the outer casing  14 , the inner casing  16  is longer than that of a typical USB receptacle, a comparison being shown in  FIGS. 3 and 4 , though the USB standard makes the length of the inner casing  16  only a reference dimension. In the USB standard, the length of the plug sheath  32  is generously proportioned and much longer than is required to mate with a typical receptacle. That is, the length of plug sheath  32  from its leading edge  32   a  to its boot or housing  100  is longer than is required, as can be seen in prior art  FIG. 3 . Some of the reasons for this extra length are common design and mounting techniques for the standard USB receptacle which allow the receptacle to be mounted to a printed circuit board (PCB), which is in turn mounted with internal components of a device (such as a computer). A housing is then mounted over the internal components, and the extra length allows a significant inset between an opening in the housing for accessing the receptacle and the receptacle cavity for receiving the plug. 
         [0051]    For automobile applications, as an example, the extra length afforded the plug sheath  32  between the leading edge  32   a  and the plug boot  100  is less necessary (compare  FIGS. 3 and 4 ), if at all. While the receptacle  10  is intended to be mounted to a PCB  17  of an automobile, the PCB  17  itself or associated electrical components (i.e., stereo components) are mounted directly to the dashboard or cover. This is in contrast where a large amount of error (variation in PCB mounting that effects the tolerance between leading edge  32   a  and plug boot  100 ) is designed into the packaging for a computer, for instance, so that precision in mounting the receptacle with the computer housing is not important. However, in an automobile, mounting directly to the dashboard or a cover thereof, greater precision in alignment of the receptacle  10  and an opening in the dashboard or cover is provided as a matter of course. Therefore, the receptacle  10  of the present invention, in use with an automobile application, need not have as large of tolerances. 
         [0052]    Turning to  FIGS. 1 and 4 , each of the inner casing  16  side portions  16   a  includes fore openings  110  and aft openings  112  allowing a portion of the supporting structure  18  to pass therethrough. The openings  110 ,  112  are generally aligned with the receptacle longitudinal axis  78  so that they are positioned along a center line of the inner casing  16  and bisecting the distance between the leaf spring retainers  66 , as well as being positioned so the leaf spring retainers  66  are aligned along a line between the openings  110 ,  112 , as can be seen in  FIG. 4 . 
         [0053]    The extended length of the plug sheath  32  in comparison to typical USB plug sheaths is not necessary, but it allows the fore opening  110  to reach farther down the plug sheath  32  (towards the boot  100 ) and, thus, significantly allows the supporting structure  18  to exert greater moment force against the plug  12  to restrict or damp movement of the plug  12  relative to the receptacle  10  than is possible with a shorter inner casing  16 . More specifically, as can be seen in  FIG. 8 , and  12 - 14 , the outer casing  14  provides a larger footprint with respect to the PCB  17 , and, as shown in  FIGS. 13 and 14 , can be mounted to the PCB  17  with screws  15 . 
         [0054]    More specifically, in  FIGS. 12-14  it can be seen that the outer casing  14  provides a constraint between the inner casing  16  and the PCB  17  which serves to enhance resistance to movement of the inner casing  16  and the PCB  17 . As such, the solder connections between the receptacle  10  need resist less force than in comparison to a typical receptacle of the prior art. Furthermore, the outer casing  16  of  FIGS. 13 and 14  can have an even greater footprint providing structure for mounting to the PCB  17  via screws  15 . 
         [0055]    Turning now to the outer casing  14  and the supporting structure  18 , in the present forms, the outer casing  14  extends over and around the inner casing  16 . By generally enlarging the entire receptacle  10  with the addition of the outer casing  14 , in comparison to typical USB receptacles, less deflection of the receptacle  10  relative to its PCB  17  due to bouncing of the USB plug  12  occurs. This improves the life of the solder connections between the receptacle  10  and PCB  17  in comparison to typical USB receptacles and associated PCBs. 
         [0056]    The outer casing  14  principally serves to retain and mount the supporting structure  18 . In an embodiment, the supporting structure  18  includes bias structures in the form of two dual-leaf springs  18   a  and  18   b  mounted within the receptacle  10 . To accommodate the dual-leaf springs  18   a  and  18   b  and deflection thereof, the outer casing  14  includes recesses  120  positioned out-board of and facing the side portions  16   a  of the inner casing  16 . Located within and extending into each recess  120  is a mount  122  for retaining and positioning one of the dual-leaf springs  18   a,    18   b.  In other forms, the supporting structure  18  may be one or more single leaf springs, bias members, spring arms, elastomers, gel-based structures, or another means; additionally, supporting structure  18  may be disposed on the plug  12 . 
         [0057]    In the present form, the mount  122  is simply a cylindrical post, and each of the dual leaf-springs  18   a,    18   b  includes a bore  124  through which the post  122  is received. When the receptacle  10  is constructed, the dual-leaf springs  18   a,    18   b  are retained on the post  122  by packaging constraints such that direct securement between the post  122  and dual-leaf springs  18   a,    18   b  is not necessary, though, alternatively, screws may be used or the post  122  may be hot-swaged or insert molded around the bore  124  to retain the dual-leaf spring  18   a,    18   b  thereon. 
         [0058]    Focusing on  FIGS. 9-11  depicting the receptacle  10  having the plug  12  removed therefrom, each dual-leaf spring  18   a,    18   b  has an elbow  130  on generally opposite ends  130   a  thereof. More specifically, the bore  124  is formed in a generally central portion  132  of the dual-leaf spring  18   a,    18   b.  Extending from the central portion  132  are two leaf arms  134 , each angled inwardly with respect to the receptacle axis  78  and towards the inner casing  16 . Each leaf arm  134  includes the ends  130   a  and elbows  130  thereof. 
         [0059]    The leaf arms  134  and elbows  130  thereof cooperate with the inner casing fore and aft openings  110  and  112 . In comparison to the leaf spring retainers  66 , the dual-leaf springs  18   a,    18   b  of the supporting structure  18  are generally larger, more robust, and have a higher spring constant. The leaf arms  134  include a first portion  139  joined contiguous and formed integral with, and angled inwardly from, the central portion  132 , a second portion  140 joined contiguous and formed integral with the first portion  139  and curved from, or angled inwardly to a greater degree than, the leaf arm first portion  139 . The second portion  140  is contiguous with a third portion  142  that curves (or angles outwardly from the second portion  140 ), the second and third portions  140 ,  142  defining the elbow  130 . The elbows  130 , in the assembled receptacle  10 , extend through the fore and aft openings  110 ,  112 , so as to contact the plug  12  when received in the receptacle  10 . 
         [0060]    With reference to  FIG. 12 , as the plug  12  is inserted in direction B, the plug sheath leading edge  32   a  contacts the third portion  142  of the elbows  130  extending through the fore openings  110 . The sheath  32  thus deflects the third portion  142  and the associated leaf arm  134  outwardly. Continuing the insertion of the plug, the plug sheath leading edge  32   a  next contacts the second portion  140  of the elbow  130  extending through the aft opening  112 , this deflecting the second portion  140  and its associated leaf arm  134  outwardly. 
         [0061]    The natural bias of the two dual-leaf springs  18   a,    18   b  serves to press inwardly on each side of the plug sheath  32 . As a result, the supporting structure  18  including the dual-leaf springs  18   a,    18   b  resists movement of the plug  12  within the receptacle  10  and damps vibrational movement of the plug  12  therewithin. Accordingly, wear between the leads  20  and  22  is significantly reduced, extending the life of the receptacle  10  and plug  12 , and significantly reducing intermittent electrical disconnect between the leads  20 ,  22 . 
         [0062]    Referring to  FIG. 1 , the receptacle  10  with the plug  12  inserted therein can be seen. Opposite sides  60  and  62  of the sheath  32  are shown with the dual-leaf springs  18   a,    18   b  contacting each side  60 ,  62  in fore and aft positions  162  and  164 . Thus, the dual-leaf springs  18   a,    18   b  cooperate as counter-balances. Where the plug  12  is deflected in direction A, for example, the plug  12  would normally (i.e., in the absence of the supporting structure  18 ) tend to rotate with the retainers elbow  94  (in the openings  64 ) and, in the present, such retainer elbows  94  and openings  64  generally provide a would-be pivot point or region. 
         [0063]    With the supporting structure  18 , such rotation is opposed and counteracted. Confronted with a vibrational force that would tend to deflect the plug  12  in the direction A, one leaf spring arm  134   a  in a fore position  162   a  is compressed to exert a greater force, while a leaf spring arm  134   b  in the other fore position  162   b  simultaneously relaxes somewhat to reduce the force it exerts on the plug  12 . Again simultaneously, a leaf spring arm  134   c  in aft position  164   a  is compressed, thereby increasing its force, while a leaf spring arm  134   d  in aft position  164   b  simultaneously relaxes and decreases the force exerted on the plug  12 . In this manner, the leaf spring arms  134   a,    134   b,    134   c,  and  134   d  cooperate to automatically and dynamically react to balance their sum force to maintain the plug  12  in the proper position, thus reducing wear on the leads  20 ,  22 . 
         [0064]    Each of the leaf spring arms  134  acts in concert with at least two of the other leaf spring arms  134  in a counter-balancing manner. As described above, the leaf spring arms  134   a  and  134   b  dynamically balance the forces they exert when the plug  12  is deflected and the spring arms  134   c  and  134   d  act similarly. However, it should also be noted that, for the above example of deflection in the direction A, leaf spring arm  134   a  and leaf spring arm  134   d  serve to increase force in opposite directions, though around the pivot point provided by the retainers  66 . Also, leaf spring arm  134   b  and leaf spring arm  134   c  decrease their force around the pivot point provided by the retainers  66 . In one form, it is possible to use a single dual-leaf spring  18   a,    18   b,  though the preferred form of this aspect of the invention is for the pair of dual-leaf springs  18   a,    18   b  to be used, as shown and described. 
         [0065]    It should also be noted that the dual-leaf springs  18   a,    18   b  may be non-linear springs (non-linear spring constants) so that the dual-leaf springs  18   a,    18   b  provide a bias force in excess of a linear increase in comparison to the amount the leaf arms  134  are deflected. For instance, movement and force applied in response thereto for a leaf arm  134  with a linear spring constant would be dictated by the equation force=deflection*k, where k is a constant. Accordingly, a 0.1 mm deflection would result in a certain force being exerted, while a 0.2 mm deflection would result in double the force being exerted. For a leaf arm  134  with a non-linear spring constant, the equation would be force=deflection*E, where E is a non-linear factor or equation so that a 0.1 mm deflection would generate a certain force X, while a 0.2 mm deflection would result in a force greater than 2X. 
         [0066]    In the present form, the outer casing  14  includes first and second shell halves  150 . The shell halves  150  are preferably identical so that assembly components and tooling for manufacturing the halves  150  are minimized. The halves  150  may be secured around the inner casing  16  in any known fashion, including using screws, as shown in  FIG. 7 , or glueing, or heat sealing, snap connections, as mere examples. 
         [0067]    Turning to  FIGS. 5 and 6 , an additional aspect of the receptacle inner casing  16  is shown. In this form, the inner casing  16  includes supporting structure in the form bias structures, specifically, spring fingers  170  positioned on sides  172  thereof, the sides  172  being aligned with the minor dimension  36  of the plug  12  and extending between sides  16   a  of the inner casing  16 . The casing  14  has openings  173  cut into the sides  172  (such as by stamping) to define the spring fingers  170 , a pair of which are formed on each of the minor dimension sides  172 . Each of the spring fingers  170  is generally tab-shaped and has a natural position that is deflected inwardly. The spring fingers  170  have a base portion  174  for connecting with the inner casing  16 , the base portions  174  of the spring fingers  170  for a given side  172  somewhat proximal to each other so that the spring fingers  170  extend away from each other. In this manner, the inner casing  16  includes four such spring fingers  170  (see  FIG. 6 ) acting in the same manner as the leaf arms  134  to dynamically balance the sum of forces therefrom, and to counteract vibration upon the plug  12 . 
         [0068]    Within the scope of the invention, the supporting structure  18  are described as operating with a standard USB plug. However, in forms within the scope of the invention, supporting structure may include interlocking structure or clamps, for instance, located either on or cooperating between the plug and the receptacle to retain the plug within the receptacle and to damp or impede or eliminate vibration forces between the plug and the receptacle and, specifically, between the leads of the plug and receptacle. 
         [0069]    While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.