Patent Publication Number: US-2012024876-A1

Title: Sealed enclosure and system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of the invention relates to enclosures generally, and more particularly to certain new and useful advances in sealed enclosures and sealing systems of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same. 
     2. Description of Related Art 
     Conventional electronics modules and/or systems generally comprise various electronics components which are attached to printed circuit boards and which may be disposed in an electronics enclosure to protect the electronics devices. The printed circuit boards provide support for electrical connections to the various electronics components attached thereto. 
     Conventional electronic modules and/or systems may be housed in separate enclosures which are typically connected to one another by one or more lines configured to carry electrical signals between the electronic modules and/or systems. The lines typically comprise conductive wires or cables having a connector at each end which are configured to be connected to the printed circuit boards located inside the electronics enclosure. 
     The enclosures housing conventional electronic modules and/or systems are frequently of a “split-box” design, comprising an enclosure top and an enclosure base, which may be hinged or separately configured to mate along an interface surface to form an interior cavity. Additionally, such enclosures conventionally comprise apertures or feed-through openings configured to allow the lines or cables to pass through the enclosure. It is frequently necessary that the interior of the enclosure be sealed from the ambient environment along the interface surface, as well as at any cable feed-through openings, in order to provide environmental protection, such as protection from ingress of an ambient fluid medium such as moisture or other liquids. Many methods, devices and systems have been used to provide a protective seal, including gaskets or grommet seals. 
     With reference to  FIGS. 1A-1E , a various views of a conventional enclosure  100  of a conventional sealing system known in the art is shown. An enclosure base  120  of enclosure  100  has a sidewall  122  with an interface surface  125  arranged to mate along a portion of a corresponding interface surface  115  on sidewall  111  of enclosure top  110 . Sidewall  122  typically includes a first notched portion  123  configured to align with a corresponding second notched portion  113  on sidewall  111  of enclosure top  110  to form an aperture  130  in order to enable feed through of one or more cables (not shown) into enclosure  100 . A first tongue  124  having an outer surface  124   a  and an inner surface  124   b  may be disposed on enclosure base. A second tongue  114  having an outer surface  114   a  and an inner surface  114   b  may be disposed on enclosure top, with each tongue  124 ,  114  extending generally orthogonal to the respective sidewalls  122 ,  111 . A grommet, such as single-piece grommet  141 , is typically disposed in aperture  130 . 
     While grommet  141  is shown in  FIGS. 1A-1E , to have a generally rectangular cross-section, conventional grommets are known to have various shapes and cross-sections generally corresponding to the shape of aperture  130 . Such grommets  141  conventionally have a body portion  144  comprising at least one peripheral rib  142  configured to be disposed within aperture  130  and to engage the inner surfaces  124   b ,  114   b  of tongues  124 ,  114 , typically under a compressive force between enclosure top  110  and base  120  in order to provide a seal. It is typically necessary that a conventional grommet  141  be compressed between enclosure top  110  and base  120  in order to provide an effective seal. 
     Conventional grommets  141  also have one or more openings  144   a  through which a corresponding cable (not shown) may be passed. 
     Additionally, a grommet cap  180  having a single peripheral outer wall  181  and an outer face  182  is conventionally provided to protect and retain the grommet  141 . The single peripheral outer wall  181  comprises an inner surface  181   a  and an outer surface  181   b  and is configured to be disposed over the first and second tongues  124 ,  114 , such that inner wall surface  181   a  is adjacent to the outer tongue surfaces  124   a ,  114   a , and outer face  182  is disposed adjacent to outer face surface  145  of grommet  141 . The face surface  182  of grommet cap  180  may be provided with one or more openings  184   a  therethrough, corresponding to the respective one or more grommet openings  144   a  and through which a cable (not shown) may likewise be passed. 
     Often, to compensate for surface irregularities along interface the surfaces  125 ,  115 , and to compensate for expansion and contraction of enclosure top  110  and base  120 , a gasket, or a sealant material, such as RTV silicon is disposed between the interface surfaces  125 ,  115  to further aid in sealing the enclosure  100 . 
     In conventional enclosures, a well-formed interface between grommet  141  and the surfaces  125 ,  115  at the notched portion of enclosure  100  is required to enable effective sealing against moisture ingress proximal to the first and second tongues  124 ,  114 . 
     Conventional sealing methods and devices have not been entirely satisfactory, for example for preventing leakage after the enclosure has been subjected to high temperature over an extended operating interval, followed by a cool-down interval. For at least the reasons stated above, a need exists for an improved enclosure and sealing system. 
     BRIEF SUMMARY OF THE INVENTION 
     One or more specific embodiments shown and/or described herein address at least the above-mentioned need. 
     In an embodiment, a cap is disclosed, the cap comprising a first outer wall having a first length L 1 , a second inner wall having a second length L 2 , said second inner wall being spaced apart from said first outer wall. 
     In another embodiment an enclosure is disclosed, the enclosure comprising a base comprising a first sidewall, said first sidewall including a first notched portion, a first tongue disposed on said first sidewall, a top comprising a second sidewall, said second sidewall comprising a second notched portion, a second tongue disposed on said second sidewall, said first notched portion being configured to align with said second notched portion to form an aperture disposed between said base and said top, a grommet cap comprising: a first outer wall having a first length L 1 ; a second inner wall having a second length L 2  and arranged to form a cavity, said second inner wall being spaced apart from said first outer wall; and a channel disposed between said first outer wall and said second inner wall, said channel being configured to receive said first and second tongues, and a grommet configured to be received within said cavity. 
     In yet another embodiment, a sealing system is disclosed, the system comprising an enclosure, the enclosure comprising a base comprising a first sidewall, said first sidewall including a first notched portion, a first tongue disposed on said first sidewall, a top comprising a second sidewall, said second sidewall comprising a second notched portion, a second tongue disposed on said second sidewall, said first notched portion being configured to align with said second notched portion to form an aperture disposed between said base and said top, a grommet cap comprising: a first outer wall having a first length L 1 ; a second inner wall having a second length L 2  and arranged to form a cavity, said second inner wall being spaced apart from said first outer wall; and a channel disposed between said first outer wall and said second inner wall, said channel being configured to receive said first and second tongues, and a grommet configured to be received within said cavity. 
     Apparatus and systems of varying scope are shown and described herein. In addition to the advantages described above, further advantages and/or adaptations or variations will become apparent by reference to the drawings and by reading the remaining portions of the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference is now made briefly to the accompanying drawings, in which: 
         FIGS. 1A and 1B  illustrate exploded views of a prior art sealing system; 
         FIG. 1C  illustrates a top view of a prior art sealed enclosure; 
         FIG. 1D  illustrates an end view of the prior art enclosure of  FIG. 1C ; 
         FIG. 1E  illustrates a section view of the prior art enclosure of  FIG. 1D  looking in the direction A-A; 
         FIG. 1F  illustrates a magnified view of a portion of the prior art enclosure of  FIG. 1E ; 
         FIG. 1G  illustrates a partial section view of the prior art enclosure of  FIG. 1E ; 
         FIGS. 2-4  illustrate exploded views of a an embodiment; 
         FIGS. 2-4  illustrate exploded views of an embodiment of the present invention; 
         FIG. 5  illustrates a perspective view of an embodiment of the grommet cap of  FIG. 3 ; 
         FIG. 6  illustrates a magnified view of a portion of an embodiment of  FIG. 4 ; 
         FIG. 7  illustrates an end view of an embodiment; 
         FIG. 8  illustrates a section view of the embodiment of  FIG. 7  looking in the direction B-B; and 
         FIG. 9  illustrates a magnified view of a portion of the embodiment of  FIG. 8 ; and 
         FIG. 10  illustrates an exploded view of an embodiment. 
     
    
    
     Like reference characters designate identical or corresponding components and units throughout the several views, which are not to scale unless otherwise indicated. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description makes reference to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments that may be practiced. It is understood that other embodiments may be utilized and that various changes can be made to the embodiments shown and described herein without departing from the patentable scope of the claims appended hereto. The following description is, therefore, not to be taken in a limiting sense. 
     As used herein, an element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the claimed invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     With reference to  FIGS. 2-4 ,  7 , and  9 , illustrations of an embodiment are shown in exploded view. Enclosure base  220  of enclosure  200  comprises a first sidewall  222  having a first interface surface  250   a  configured to mate with a corresponding portion of a second interface surface  250   b  on a second sidewall  211  of enclosure top  210  to form a seam  202  (Ref.  FIG. 7 ). First sidewall  222  further comprises a first notched portion  223  (Ref.  FIG. 4 ) configured to generally align with a corresponding second notched portion  213  on second sidewall  211  of enclosure top  210  to form an enclosure aperture  230  (Ref.  FIG. 9 ) disposed between the enclosure top  210  and base  220 . Enclosure aperture  230  is configured to receive at portion of a grommet cap  280  ( FIG. 5 ). A first tongue  252 , having a first inner surface  252   a  and an first outer surface  252   b , is disposed on enclosure base  220 , and a second tongue  251 , having a second outer surface  251   a  and a second inner surface  251   b , is disposed on enclosure top  210 , with the first and second tongues  251 ,  252  preferably extending generally orthogonal to the respective sidewalls  211 ,  222 . 
     A grommet  241  is provided, having a body portion  244  configured to be disposed within a grommet cap  280  and preferably formed of flexible elastomeric material such as silicone rubber or urethane. Body portion  244  of grommet  241  preferably comprises at least one peripheral sealing rib  242 . While grommet  241  is shown in the figures to have a generally rectangular cross-section, in various embodiments, the grommet  241  may be configured in various shapes, geometries, and cross-sections generally corresponding to the shape of grommet cap cavity  289 . In an embodiment, the outer face surface  245  of grommet  241  comprises one or more openings  243  through which a corresponding cable (not shown) may be passed. 
     With reference to  FIGS. 4 ,  5 ,  8 , and  9 , the grommet cap  280  is configured to cooperate with the first and second tongues  252 ,  251  and disposed to cover grommet  241 . Grommet cap  280  comprises a first outer sealing wall  281  having a first length L 1 , a first outer sealing wall outer surface  281   a , and a first outer sealing wall inner surface  281   b . Grommet cap  280  additionally comprises a second inner sealing wall  283  having a second length L 2 , a second inner sealing wall outer surface  283   a , and a second inner sealing wall inner surface  283   b . The second inner sealing wall  283  is arranged to define a cavity  289  configured to receive grommet  241 . In an embodiment, the second inner sealing wall  283  is further configured to be received within the enclosure aperture  230 . In an embodiment, the second inner sealing wall surface  283   b  provides an uninterrupted surface configured to engage the at least one peripheral rib  242  of grommet  241 . In an embodiment, the first length L 1  of the first outer sealing wall  281  is less than the second length L 2  of the second inner sealing wall  283 . The first outer sealing wall  281  and the second inner sealing wall  283  are spaced apart to form a channel  286 . The channel  286  is dimensioned to receive the first and second tongues  252 ,  251 . Grommet cap  280  additionally comprises a third face wall  282 , preferably oriented generally orthogonal to channel  286  and configured to be disposed over outer face surface  245  of grommet  241 . Grommet cap  280  is configured to be disposed over a portion of grommet  241  such that the second inner sealing wall  283  is disposed between grommet  241  and the tongues  252 ,  251  of the enclosure base  220  and top  210 . Grommet cap  280  thereby prevents grommet  241  from contacting the seam  202 , mating surfaces  250   a ,  250   b , and tongues  252 ,  251  of the enclosure base  220  and top  210  to more effectively seal the enclosure  200 . 
     In an embodiment, grommet cap  280  is provided with one or more openings  287  through the face surface  282 , preferably corresponding to the grommet openings  243 , and through which one or more cables (not shown) may be passed. 
     In an embodiment, an adhesive sealant material (not shown), such as room temperature vulcanizing RTV silicone rubber, may be disposed between at least one of the first and second tongues  251 ,  252  and at least one of the first outer wall  281  and second inner wall  283  to provide a seal with grommet cap  280  to further protect against moisture ingress into enclosure  200 . 
     In an embodiment, a portion of the second inner sealing wall outer surface  283   a  of grommet cap  280  is configured to engage the first notched surface portion  223  of first sidewall  222  and the second notched surface portion  213  on second sidewall  211 . In an embodiment, the first notched surface portion  223  of sidewall  222  is provided with at least one engagement feature, such as for example a groove  227  configured to cooperate with an engagement rib  288  disposed on the first outer sealing wall outer surface  281  to provide a retention force against grommet cap  280 . 
     This specification, including the claims, abstract and drawings, is intended to cover any adaptations or variations of the specific embodiments illustrated and described herein. Accordingly, the names of elements, components or features, of the above-described system, methods, and apparatus are not intended to be limiting. It is contemplated that the above-described embodiments, whether adapted or varied or not, are applicable to future enclosure apparatus and systems. Moreover, the terminology used herein is intended to encompass all enclosures and systems that provide the same or equivalent functionality described herein. 
     Although effort was made to show all of the particular elements, components or features of each of the above-described specific embodiments in separate figures, this may not have been possible. In the event that one or more elements, components or features of one or more of the above-described specific embodiments are shown in some drawings and not in others, it is contemplated that each element, component or feature of one drawing may be combined with any or all of the other elements, components or features shown in any or all of the remainder of the drawings, as described herein, as claimed herein or in any other suitable fashion. 
     The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Additionally, patentable scope is defined by the following claims, which are intended to encompass not only the specific embodiments described above, but also adaptations or variations thereof (i) that have structural elements that do not differ from the literal language of the claims, or (ii) that have equivalent structural elements with insubstantial differences from the literal language of the claims.