Abstract:
A method and apparatus involve: configuring a wall portion to have an opening therethrough and to have a first annular surface extending around the opening; supporting on a circuit board an electrical connector having a plurality of electrical contacts and having a second annular surface; and resisting fluid flow from one side of the wall portion to an opposite side thereof through the opening, including compressing between the first and second annular surfaces a seal ring having third and fourth annular surfaces that respectively engage the first and second annular surfaces, the electrical contacts each having a portion that is accessible through the opening.

Description:
[0001]    This application claims the priority under 35 U.S.C. §119 of provisional application number 61/080,400 filed Jul. 14, 2008, the disclosure of which is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates in general to a housing with an externally accessible electrical connector and, more particularly, to techniques for providing a seal between the interior and exterior of the housing in the region of the connector. 
       BACKGROUND 
       [0003]    There are a variety of applications where a device has a housing with electrical circuitry therein, and is used in an environment that includes exposure to one or more environmental conditions such as dust, grease, moisture, snow, pressurized water, high humidity, or temperature extremes. It is often necessary to provide an electrical connector that is electrically coupled to the circuitry within the housing, and that is accessible from externally of the housing. It is desirable that fluids, moisture and/or environmental contaminants be prevented from entering the housing through or adjacent the connector. Although pre-existing techniques for providing a sealed electrical connector have been generally adequate for their intended purposes, they have not been satisfactory in all respects. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    A better understanding of the present invention will be realized from the detailed description that follows, taken in conjunction with the accompanying drawings, in which: 
           [0005]      FIG. 1  is a diagrammatic perspective front view of a sealed electrical connector. 
           [0006]      FIG. 2  is a diagrammatic perspective rear view of the connector of  FIG. 1 . 
           [0007]      FIG. 3  is a diagrammatic exploded perspective front view of the connector of  FIG. 1 . 
           [0008]      FIG. 4  is a diagrammatic exploded perspective rear view of the connector of  FIG. 1 . 
           [0009]      FIG. 5  is a diagrammatic perspective front view of a support member that is a component of the connector of  FIG. 1 . 
           [0010]      FIG. 6  is a diagrammatic perspective rear view of the support member of  FIG. 5 . 
           [0011]      FIG. 7  is a diagrammatic perspective view of five electrically conductive elements that are components of the connector of  FIG. 1 . 
           [0012]      FIG. 8  is a diagrammatic perspective view showing the five conductive elements of  FIG. 7  installed in the support member of  FIGS. 5-6 . 
           [0013]      FIG. 9  is a diagrammatic sectional view taken along the section line  9 - 9  in  FIG. 4 . 
           [0014]      FIG. 10  is a diagrammatic perspective front view of an assembly that includes the support member and conductive elements of  FIG. 7 , and also an overmold that is a further component of the connector of  FIG. 1 . 
           [0015]      FIG. 11  is a diagrammatic perspective rear view of the assembly of  FIG. 10 . 
           [0016]      FIG. 12  is a diagrammatic fragmentary sectional view of a portion of a radio frequency identification (RFID) tag that includes the connector of  FIGS. 1-11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1  is a diagrammatic perspective front view of a sealed electrical connector  10  having a portion that can be mechanically and electrically coupled to a standard and not-illustrated miniature Universal Serial Bus (mini-USB) type B connector. The term “connector” is used generically herein, and encompasses either a male connector or a female receptacle, as well as other possible connector configurations. As one example, the connector could be a micro-USB connector rather than a mini-USB connector. 
         [0018]      FIG. 2  is a diagrammatic perspective rear view of the connector  10  of  FIG. 1 .  FIG. 3  is a diagrammatic exploded perspective front view of the connector  10  of  FIG. 1 .  FIG. 4  is a diagrammatic exploded perspective rear view of the connector  10  of  FIG. 1 . With reference to  FIGS. 1-4 , the connector  10  includes a support member  16 , five electrically conductive elements  21 - 25 , an overmold  28 , a shield  31 , and a gasket  33 . 
         [0019]      FIG. 5  is a diagrammatic perspective front view of the support member  16 .  FIG. 6  is a diagrammatic perspective rear view of the support member  16 . The support member  16  is made of an electrically insulating material. In the disclosed embodiment, the support member  16  is made from a liquid crystal polymer (LCP) material that is available commercially under the tradename VECTRA® E130i™ from Ticona of Florence, Ky. Alternatively, however, the support member  16  could be made of any other suitable material. As shown in  FIGS. 5 and 6 , the support member  16  has a platelike and approximately rectangular base  51 , and an elongate projection  52  that extends outwardly from one side of the base. The projection  52  has a cross-sectional shape that is approximately rectangular, except that the lower edges of the projection  52  are each beveled at  56  and  57 . 
         [0020]    The support member  16  has five parallel slots or channels  61 ,  62 ,  63 ,  64  and  65  therein. The channels  61 - 65  each open upwardly through top surfaces of the support member  16 , and each open rearwardly through a rear surface of the support member. The channels  61 - 65  each extend most of the length of the projection  52 , but stop short of the outer end of the projection. The channels  61 - 65  each have a pair of downwardly facing shoulders that extend the length thereof, as shown at  67  and  68  in  FIG. 6  for the channel  61 . Each of the channels  61 - 65  has, on each side thereof and below the shoulders  67  and  68 , a pair of horizontally-spaced bosses that are not visible in the drawings. The projection  52  has five openings  71 - 75  that are each of rectangular cross-section, that each have one end opening through the outer end of the projection  52 , and that each have another end opening into a respective one of the channels  61 - 65 . 
         [0021]      FIG. 7  is a diagrammatic perspective view of the five conductive elements  21 - 25 . In the disclosed embodiment, the elements  21 - 25  are each made from bronze, but they could alternatively be made from any other suitable material that is electrically conductive. The conductive elements are resiliently flexible. Each of the conductive elements  21 - 25  is flat and elongate. Each has a horizontal central section with two laterally outward projections disposed on opposite sides thereof, for example as shown at  81  and  82  for the conductive element  21 . The conductive element  21  has an end section  91  with an inverted V shape, in that it extends upwardly away from the central section, and then downwardly toward its outer end. The conductive elements  22 - 25  have similar end sections  92 - 95 , respectively. The end sections  91 - 95  each serve as an electrical contact, and are sometimes referred to herein as contacts. 
         [0022]    At their opposite ends, the conductive elements  21 - 25  have respective end sections  101 - 105  that extend horizontally outwardly. The end sections  101 - 105  each serve as an electrical lead, and are sometimes referred to herein as leads. The conductive element  21  has an S-shaped bend  108  located between the end section  101  and the central section with projections  81  and  82 . The conductive elements  23  and  25  have similar bends. In contrast, the conductive elements  22  and  24  do not have bends comparable to the bend  108 , but instead extend horizontally outwardly from their central sections to their end sections  102  and  104 . 
         [0023]      FIG. 8  is a diagrammatic perspective view showing the five conductive elements  21 - 25  installed in the support member  16 . As discussed above in association with  FIG. 7 , the conductive element  21  has a central section with outward projections  81  and  82 . This central section is disposed in the lower portion of the channel  61 , below the shoulders  67  and  68  ( FIG. 6 ). As discussed above, the channel  61  has on each side thereof, below the shoulder  67  or  68 , a pair of horizontally-spaced bosses that are not visible in the drawings. The projections  81  and  82  on the conductive member  21  are each disposed between a respective pair of the bosses in the channel  61 . The bosses cooperate with the projections  81  and  82  so as to prevent the central section of the conductive element  21  from moving lengthwise within the channel. The shoulders  67  and  68  engage the top sides of the projections  81  and  82 , so as to prevent the central section of the conductive element  21  from moving upwardly within the channel  61 . In a similar manner, the central sections of the conductive elements  22 - 25  are each held in place in a respective one of the channels  62 - 65 . 
         [0024]      FIG. 9  is a diagrammatic sectional view taken along the section line  9 - 9  in  FIG. 4 . As discussed above, the conductive element  24  has an end section  94  with an inverted V-shape that serves as an electrical contact. The end section  94  has an outer end  111  that is vertically movably received within the opening  74  in the support member  16 . The inherent resilience of the support member  24  urges the end section  94  upwardly. Engagement of the outer end  111  with the top surface in the opening  74  limits upward movement of the end section  94 . It will be noted that, in the uppermost position of the end section  94 , the center of the end section  94  projects upwardly beyond a top surface  113  on the projection  52  of the support member  16 . In response to a downward force indicated diagrammatically at  114 , the conductive element  24  can flex so that the end section  94  moves downwardly within the channel  64 . When the downward force  114  is removed, the inherent resilience of the conductive element  24  returns the end section  94  to the position shown in  FIG. 9 . 
         [0025]    After the conductive elements  21 - 25  have been installed in the support member  16 , in order to obtain the assembly shown in  FIG. 8 , this assembly is placed in a not-illustrated injection mold. The cavity in the injection mold is then filled with a moldable material that is allowed to harden, and becomes the overmold  28  ( FIGS. 3-4 ).  FIG. 10  is a diagrammatic perspective front view of an assembly that includes the support member  16  and the conductive elements  21 - 25 , with the overmold  28  formed thereon.  FIG. 11  is a diagrammatic perspective rear view of the assembly of  FIG. 10 . In the disclosed embodiment, the overmold  28  is made from a rigid and durable plastic material of a type known in the art. However, it could alternatively be made from any other suitable material. 
         [0026]    With reference to  FIGS. 10 and 11 , the overmold  28  has a platelike base  131  that is approximately rectangular, except that the corners are rounded. On its rear side, the base  131  has a shallow recess  133  ( FIG. 11 ) that is also approximately rectangular in shape, except that its corners are rounded. The recess  133  has a planar inner end surface  134 . The five conductive elements  21 - 25  each extend completely through the overmold  28 , and their end sections  101 - 105  extend through the inner end surface  134  of the recess  133 , and project rearwardly beyond the rear surface of the overmold. 
         [0027]    The overmold  28  also includes a projection  146  that is integral with the base  131 , and that extends forwardly from the center of the front side of the base. The projection  146  has a smaller cross-sectional size than the base  131 . The base  131  has a forwardly-facing annular surface  148  that extends around the projection  146 . The base  51  ( FIGS. 5-6 ) of the support member  16  is embedded within the projection  146  of the overmold  28 , and a short portion of the projection  52  of the support member is also embedded within the projection  146 . The remainder of the projection  52  extends forwardly beyond the front end of the projection  146 . 
         [0028]    The end sections  91 - 95  of the conductive elements  21 - 25  are accessible in front of the overmold  28  ( FIG. 10 ), and the opposite end sections  101 - 105  of the elements  21 - 25  are accessible behind the overmold  28  ( FIG. 11 ). The base  131  of the overmold  28  has four small, spaced, parallel openings  151 - 152  extending therethrough. Each of the openings  151 - 154  has a rectangular cross section, opens at one end through the annular surface  148 , and opens at the other end through the inner end surface  134  of the recess  133 . The openings  151  and  152  are located above the projection  146 , and the openings  153  and  154  are located below the projection  146 . 
         [0029]    Referring again to  FIGS. 3 and 4 , the shield  31  has a tubular main section  159 . The opening through the main section  159  has a cross-sectional shape and size conforming closely to the cross-sectional shape and size of the projection  146  of the overmold  28 . The shield  31  has four parallel legs  161 - 164  that project outwardly from the rear end of the main section  159 . During assembly of the connector  10 , the projection  146  is inserted into the opening through the main section  159  of the shield  31 , and the legs  161 - 164  of the shield are each inserted with a force fit into a respective one of the openings through the overmold  28 . In the assembled state, the outer ends of the legs  161 - 164  project rearwardly beyond the rear surface of the overmold  28 . The overmold  28  provides a fluid seal around each of the conductive elements  21 - 25  and each of the legs  161 - 164  of the shield  31 . As result, fluids and contaminants cannot pass through the overmold  28  from one side thereof to the other side along any of the conductive elements  21 - 25  or along any of the legs  161 - 164 . To facilitate the fluid seal between the overmold  28  and each of the conductive elements  21 - 25  and each of the legs  161 - 164 , the material used for the overmold in the disclosed embodiment has a coefficient of thermal expansion (CTE) that is approximately the same as the CTE of the conductive elements  21 - 25  and the legs  161 - 164 . 
         [0030]    On the upper side of the tubular main section  159 , there are three C-shaped cutouts that each define a respective resiliently-flexible tab  167 ,  168  or  169 . The tabs  167 - 169  are each bent so that a portion thereof projects downwardly a small distance into the opening through the tubular shield  31 . Each of the tabs  167 - 169  can be flexed upwardly a small amount against the inherent resilience thereof, and the inherent resilience urges each tab to return to its original position. 
         [0031]    As shown in  FIGS. 3 and 4 , the gasket  33  is platelike, and is of approximately rectangular shape, except that the corners are rounded. The gasket  33  has an opening  181  extending therethrough. The opening  181  is congruent in size and shape with the exterior of the shield  31 . On the front side, the gasket  33  has a forwardly-facing annular surface  183  that extends around the opening  181 . On the rear side, the gasket  33  has a rearwardly-facing annular surface  184  that extends around the opening  181 . In the assembled state of the connector  10 , the main section  159  of the shield  31  extends with a snug fit through the opening  181  in the gasket  33 , and the annular surface  184  on the gasket  33  engages the annular surface  148  on the base  131  of the overmold  28 . In the disclosed embodiment, the gasket  33  is resiliently compressible and made of silicone, but it could alternatively be made of any other suitable material. 
         [0032]    The connector  10  has a portion that is defined by the main section  159  of the shield  31 , the end sections  91 - 92  of the conductive elements  21 - 25 , and the exposed part of the projection  52  on the support member  16 . This portion of the connector  10  can be coupled to a standard and not-illustrated type B mini-USB connector, with the end sections  91 - 95  of the conductive elements  21 - 25  serving as electrical contacts. With reference to  FIG. 1 , and in a manner known in the art, an end of the not-illustrated connector is inserted into the opening through the tubular shield  31 , such that a not-illustrated portion thereof is disposed between the tabs  167 - 169  and the top surface  113  ( FIG. 9 ) of the projection  52 . The tabs  167 - 169  yieldably urge this portion of the not-illustrated connector downwardly so that it slidably engages the top surface  113  of the projection  52 . 
         [0033]    Further, this portion of the not-illustrated connector has five not-illustrated electrical contacts that each slidably engage a respective one of the five electrical contacts  91 - 95 , and that move the contacts  91 - 95  downwardly within the channels  61 - 65 , by flexing the conductive elements  21 - 25 . Each of the deflected contacts  91 - 95  is urged upwardly by the inherent resilience of the conductive elements, thereby ensuring a good electrical connection between each of the contacts  91 - 95  and the corresponding contact of the not-illustrated connector. The not-illustrated connector can later be disengaged from the connector  10 , by manually pulling it out of the shield  31  of the connector  10 . The contacts  91 - 95  then return to their original positions, due to the inherent resilience of the conductive elements  21 - 25 . 
         [0034]      FIG. 12  is a diagrammatic fragmentary sectional view of part of an apparatus  301  that is a radio frequency identification (RFID) tag, and that includes the connector  10  of  FIGS. 1-11 . Although the apparatus  301  in  FIG. 12  happens to be an RFID tag, it could alternatively be any of a variety of other types of devices. The tag  301  has a housing  306 . In the disclosed embodiment, the housing  306  is made of a rigid and durable plastic material, but could alternatively be made of any other suitable material. The housing  306  has a wall  307  with an outer surface  309 , and a recess  308  is provided in the surface  309  of the wall  307 . An opening  311  extends from the inner end of the recess  308  through the wall  307 , and opens into the interior of the housing through a surface  313  provided on the inner side of the wall  307 . The opening  311  has a size that is smaller than the size of the recess  308 . 
         [0035]    A circuit board  316  is provided inside the housing  306 , and is fixedly secured to the housing  306  by two or more screws  317  and  318 . The screws  317  and  318  each have a threaded shank that extends through a respective opening in the circuit board  316 , and that engages a respective threaded opening provided in the housing  306 . The connector  10  of  FIGS. 1-11  is mounted on the top side of the circuit board  316 . The leads  101 - 105  and the legs  161 - 164  each extend through a respective opening provided in the circuit board  316 , and project a short distance beyond the lower surface of the circuit board. The underside of the circuit board has electrically-conductive runs or traces that are not visible in the drawings, and the leads  101 - 105  and legs  161 - 164  are each soldered to a run or trace on the circuit board. 
         [0036]    The shield  31  of the connector  10  projects upwardly through the opening  311  in the housing  306 , and has its upper end disposed within the recess  308 . The gasket  33  is disposed between the overmold  28  and an inner surface  313  of the housing wall  307 . The annular surface  183  on the gasket  33  engages an annular portion of the inner surface  313 , and the annular surface  184  of the gasket  33  engages the annular surface  148  on the overmold  28 . When the circuit board  316  is snugly secured in place by the screws  317  and  318 , the gasket  33  is compressed between the surface  148  on the overmold  28  and the surface  313  on the housing wall  307 . As a result, the gasket  33  serves as a seal ring that provides a fluid seal around the shield  31 , so as to prevent moisture, fluid or contaminants disposed outside the housing  306  from entering the housing by passing between the surfaces  313  and  148 . Also, as explained earlier, fluid cannot pass through the overmold  28  from one side thereof to the other side. Thus, the overmold  28  and the gasket  33  cooperate to prevent any fluid, moisture or contaminants located outside the housing  306  from passing through the recess  308  and the opening  311 , and entering the interior of the housing. 
         [0037]    An elongate flexible strap  332  has one end fixedly secured to the housing  306  by a screw  333 . The screw has a threaded shank that extends through an opening in the strap  332 , and that engages a threaded opening provided in the housing. The strap  332  has an integral portion  336  that is shaped to serve as a plug. The strap  332  and plug  336  serve as a one-piece cover. The plug  336  can be removably and snugly inserted into the recess  308  in the housing  306 , primarily to protect the connector  10  from possible physical damage from elements in the environment external to the housing  306 , but also to provide a limited degree of sealing against dust, grease, moisture, snow, pressurized water, high humidity, and the like. The strap  332  serves as a retention element that prevents loss of the plug  336  when the plug is not in the recess  308 . In the disclosed embodiment, the strap  332  and plug  336  are made from rubber which, in the disclosed embodiment is rubber with a hardness of Shore A durometer  80 . However, the strap and plug could alternatively be made from any other suitable material. 
         [0038]    With reference to  FIG. 2 , it would be possible to provide within the  133  a not-illustrated optional gasket that is made from a resiliently compressible material, that has nine small openings therethrough which each snugly receive a respective one of the elements  101 - 105  and legs  161 - 164 , that has a thickness somewhat greater than the depth of the recess  133 , and that has a peripheral edge profile conforms closely to the shape of the peripheral edge of the recess  133 . When the connector  10  is mounted on and soldered to a not-illustrated circuit board, the gasket becomes compressed between the circuit board and the connector  10 , thereby helping to provide a fluid seal around each of the elements  101 - 105  and the legs  161 - 164 . 
         [0039]    As yet another alternative, instead of providing a gasket within the recess  133 , the recess could be filled with a not-illustrated resin or epoxy material that is commercially available and that hardens in place to help provide a fluid seal around each of the elements  101 - 105  and the legs  161 - 164 . This material could, for example, be a material that bonds directly and tightly to the material of the elements  101 - 105  and legs  161 - 164 . 
         [0040]    Although a selected embodiment has been illustrated and described in detail, it should be understood that a variety of substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the claims that follow.