Abstract:
An assembly includes: a mounting structure having a threaded member; a generally annular adapter, the adapter having threads that engage the threaded member, the adapter further including a radially outward sealing surface formed of one of the materials; an electrical cable having a connector threaded onto the threaded member, and a sealing boot that covers the connector and engages the sealing surface of the adapter.

Description:
RELATED APPLICATION 
       [0001]    The present application claims priority from and the benefit of U.S. Provisional Patent Application No. 61/908,977, filed Nov. 26, 2013, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to a device for environmentally sealing and securing the interconnection between electrical cables. 
       BACKGROUND 
       [0003]    Electrical interconnections, such as the interconnection between two cables or a cable and a piece of electronic equipment, may be subject to degradation from environmental factors such as moisture, vibration and repeated expansion and contraction from daily temperature changes. Outer sealing enclosures that surround or enclose an electrical interconnection have been used to protect such interconnections. Enclosures often apply rigid clamshell configurations that, once closed, may be difficult to open, especially when installed in exposed or remote locations, such as atop radio towers; gaskets or gel seals may be applied at the enclosure ends and/or along a sealing perimeter of the shell. 
         [0004]    Elastic interconnection seals are also known. Elastic seals can be advantageous by virtue of being more easily installed over the typically uneven contours of an electrical interconnection. Exemplary configurations are described in U.S. patent application Ser. No. 13/646,952, filed Oct. 8, 2012, and U.S. patent application Ser. No. 13/938,475, filed Jul. 10, 2013, the disclosures of each of which are hereby incorporated by reference herein. 
       SUMMARY 
       [0005]    As a first aspect, embodiments of the invention are directed to a sealing adapter for enhancing sealing of a sealing device and a threaded member. The adapter comprises: a generally annular outer shell formed of a first material, the outer shell having first and second longitudinal ends and an inner surface, the inner surface including at least one thread; and a generally annular inner core formed of a second material that differs from the first material, the inner core including a threaded inner surface that combines with the at least one thread of the outer shell to form a threaded arrangement configured to be received on a threaded member. 
         [0006]    As a second aspect, embodiments of the invention are directed to an assembly, comprising: a mounting structure having a threaded member; a generally annular adapter, the adapter having threads that engage the threaded member, the adapter further including a radially outward sealing surface formed of one of the materials; an electrical cable having a connector threaded onto the threaded member, and a sealing boot that covers the connector and engages the sealing surface of the adapter. 
         [0007]    As a third aspect, embodiments of the invention are directed to a method of forming a sealing adapter, comprising the steps of: (a) injection molding a generally annular outer shell with a first material, the outer shell having first and second longitudinal ends and an inner surface, the inner surface including at least one thread; and (b) injection molding a generally annular inner core formed of a second material that differs from the first material, the inner core including a threaded inner surface that combines with the at least one thread of the outer shell to form a threaded arrangement configured to be received on a threaded member, the inner core further comprising an outer surface that presents a sealing location for the sealing device, wherein step (b) is carried out in a mold that contains the already-formed outer shell. 
         [0008]    As a fourth aspect, embodiments of the inventions are directed to a sealing adapter for enhancing sealing of a sealing device and a threaded member, comprising: a generally annular outer ring; a generally annular inner ring that is concentric with the outer ring, wherein a generally annular gap is formed between the outer ring and the inner ring; and one or more threads extending radially inwardly from an inner surface of the inner ring. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0009]      FIG. 1  is a top view of an antenna, remote radio head (RRH) or other mounting structure with a threaded stem for electrical connection. 
           [0010]      FIG. 1A  is a top view of an enlarged section of the threaded stem of  FIG. 1  with a sealing boot applied. 
           [0011]      FIG. 2  is a top view of an alternative mounting structure with a threaded stem with threads along most or all of its length. 
           [0012]      FIG. 2A  is a top view of an enlarged section of the threaded stem of  FIG. 2  with a sealing boot applied. 
           [0013]      FIG. 3  is a top view of the mounting structure of  FIG. 2  including a sealing adapter in accordance with embodiments of the present invention. 
           [0014]      FIG. 3A  is a top view of an enlarged section of the threaded stem and sealing adapter of  FIG. 3  with a sealing boot applied and with a connecting nut in place on the threaded stem, with the sealing adapter and sealing boot shown in section view. 
           [0015]      FIG. 3B  is a further enlarged top/section view of the threaded stem, sealing adapter and sealing boot of  FIG. 3A . 
           [0016]      FIG. 4  is a perspective view of the outer core of the sealing adapter of  FIG. 3 . 
           [0017]      FIG. 5  is an enlarged top view of the outer core of the sealing adapter of  FIG. 3 . 
           [0018]      FIG. 6  is an enlarged section view of the outer core of the sealing adapter of  FIG. 3 . 
           [0019]      FIG. 7  is an enlarged section view of the outer shell and inner core of the sealing adapter of  FIG. 1 . 
           [0020]      FIG. 8  is a section view of a sealing adapter according to alternative embodiments of the invention. 
           [0021]      FIG. 9  is a section view of a sealing adapter according to further alternative embodiments of the invention. 
           [0022]      FIG. 10  is a section view of a sealing adapter according to still further alternative embodiments of the invention. 
           [0023]      FIG. 11  is a section view of a sealing adapter according to yet further alternative embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The present invention is described with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments that are pictured and described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It will also be appreciated that the embodiments disclosed herein can be combined in any way and/or combination to provide many additional embodiments. 
         [0025]    Unless otherwise defined, all technical and scientific terms that are used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this disclosure, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when an element (e.g., a device, circuit, etc.) is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
         [0026]    Referring now to the figures, exemplary mounting structures for attachment of an electrical cable are shown in  FIGS. 1-3B . The mounting structures  10  (in  FIGS. 2-3B ) and  10 ′ (in  FIGS. 1 and 1A ) may be any mounting structure having an electrical connector with a threaded stem  12 ,  12 ′ to which an electrical cable can be attached via a mating connector. As examples, the mounting structures  10 ,  10 ′ may be an antenna, RRH, or the like. 
         [0027]    The mounting structure  10 ′ includes a threaded stem  12 ′ that has a smooth surface  13 ′ adjacent the bulkhead of the mounting structure  10 ′ and a threaded surface  14 ′ on its free end (see  FIG. 1A ). The smooth surface  13 ′ provides a surface appropriate for sealing with a sealing boot  16 ′ or the like. In contrast, the mounting structure  10  of  FIGS. 2 and 2A  includes a threaded stem  12  that has a predominantly, if not entirely, threaded surface  14 . As can be seen in  FIG. 2A , the sealing boot  16  (which is typically formed of an elastomeric material such as rubber) contacts the threads of the threaded surface  14 , which can create voids in the engagement between the sealing boot  16  and the stem  12  through which water and other environmental agents can seep. 
         [0028]    Referring now to  FIGS. 3-7 , a sealing adapter, designated broadly at  30 , is illustrated therein. As can be seen in  FIGS. 4 and 6 , the sealing adapter  30  is generally annular and defines a longitudinal axis L. The sealing adapter  30  is a composite of a relatively soft inner core  40  with a relatively harder outer shell  60 ; these components are described in greater detail below. 
         [0029]    The outer shell  60  has a generally annular body  62  with overhanging, radially outwardly-extending upper and lower rims  64 ,  65 , with the result that, in cross-section, the profile of the outer shell  60  is generally C-shaped (see  FIG. 3A and 6 ). The inner surface  63  of the body  62  includes two upper quarter threads  66  adjacent one end of the outer shell  60  and two lower quarter threads  68  adjacent the other end of the outer shell  60 . The upper quarter threads  66  are located opposite from each other across the body  62  (i.e., they are offset from each other by about 180 degrees), as are the two lower quarter threads  68 , with the lower quarter threads  68  being offset from the upper quarter threads  66  by about 90 degrees (see  FIGS. 4 ,  5  and  6 ). All of the quarter threads  66 ,  68  are canted relative to the longitudinal axis L of the body  62  (see one upper quarter thread  66  and one lower quarter. thread  68  in  FIG. 6 ) to enable the outer shell  60  to receive the threaded stem  12  of the mounting structure  10 . Four ribs  71  connect the ends of adjacent quarter threads  66 ,  68  and merge with shoulders  72  that span the arc of each quarter thread  66 ,  68  flush with the adjacent rim  64 ,  65 . Four holes  70  are formed circumferentially equidistant from each other in the body  62 . 
         [0030]    As described above, the outer shell  60  is formed of a material that is relatively harder than that of the inner core  40 , and is typically one that exhibits good strength and rigidity. Exemplary materials for the outer shell include polypropylene and nylon. 
         [0031]    The inner core  40  includes an inner ring  42  that has inwardly-extending threads  44  sized to mate with the threads  14  of the threaded stem  12 . As can be seen in  FIG. 3B , the inner ring  42  resides radially inwardly of the body  62  of the outer shell  60  and between the upper and lower quarter threads  66 ,  68 . Together, the threads  44  and the upper and lower quarter threads  66 ,  68  of the outer shell  60  form a threaded arrangement configured to be received on the threaded stem  12  of the mounting structure  10 . The inner core  40  also includes an outer ring  46  that resides between and is sandwiched by the upper and lower ledges  64 ,  65  of the outer shell  60 . The outer ring  46  presents an outer sealing surface  48 . The inner and outer rings  42 ,  46  are connected by segments that extend through the holes  70  in the outer shell  60 . 
         [0032]    As noted above, the inner core  40  is typically formed of a material that is relatively softer than that of the outer shell  60 . Exemplary materials for the inner core  40  include rubber, silicone rubber and EPDM. 
         [0033]    As can be seen in  FIGS. 3A and 3B , the adapter  30  can be threaded onto the threads of the threaded surface  14  of the threaded stem  12  of the mounting structure  10 . The quarter threads  66 ,  68  of the outer shell  60  provide a firm, strong, substantially rigid engagement with the threaded surface  14 . In contrast, the resilience of the threads  44  of the inner core  40  provides a seal between the adapter  30  and the threaded surface  14 . Thus, the adapter  30  can provide an interface with the threaded stem  12  that is both mechanically sound and sealed. It should also be noted that the approximately 180 degree spacing of the upper quarter threads  66  and similar spacing of the lower quarter threads  68  can provide stability to the adapter  30  as and after it is threaded into place. 
         [0034]    As shown in  FIG. 3A , a sealing boot  16  can then be applied over the adapter  30  such that a sealing surface  17  of the sealing boot  16  contacts and overlies the outer sealing surface  48  of the adapter; engagement between these two surfaces  17 ,  48  provides a seal between the adapter  30  and the sealing boot  16 . Thus, there are no voids that might otherwise be created by the sealing boot  16  and the threaded surface  14  alone (see  FIG. 3A ). 
         [0035]    Referring now to  FIG. 6 , it can be understood that the outer shell  60  of the adapter  30  can be formed by a relatively straightforward injection molding process due to the configuration of the quarter threads  66 ,  68 .  FIG. 6  shows one upper quarter thread  66  and one lower quarter thread  68 , which are spaced from each other about the longitudinal axis L by about 90 degrees; as described above, the other upper quarter thread  66  is spaced and 180 degrees from the illustrated upper quarter thread  66 , and the other lower quarter thread  68  is spaced about 180 degrees from the illustrated lower thread  68 . Those skilled in this art will appreciate that the mold halves of an injection mold can form the quarter threads  66 ,  68  by simply separating along the longitudinal axis L of the outer shell  60 ; there is no need for any “side action” mechanism in the mold to form the quarter threads  66 ,  68 , which could complicate the mold construction and molding process. The holes  70  can also be formed during the molding process by a side action in the mold perpendicular to the longitudinal axis L; alternatively, they may be drilled or otherwise formed later. 
         [0036]    Once the outer shell  60  is formed, it can be placed in a second injection mold, wherein softer material is injected to form the inner core  40 . The presence of the holes  70  enables the softer material to flow into the section of the mold that forms the inner ring  42 . The material of the inner core  40  is sufficiently flexible that the threads  44  of the inner core  40  can deform to enable the adapter  30  to be removed from the mold. 
         [0037]    Those skilled in this art will appreciate that other configurations of the adapter  30  may also be suitable. For example, the arrangement of the threads of the outer shell  60  may vary; two half threads or eight eighth threads may be employed rather than four quarter threads, threads may be provided only at one end of the outer shell  60 , and/or the offsets of the threads may be varied or omitted. As another example, the upper and lower rims  64 ,  65  of the outer shell  60  may be omitted, such that the sealing surface  48  of the outer ring  46  of the inner core  40  extends the full length of the adapter  30 . More or fewer holes  70  (e.g., two holes, six holes, eight holes, etc.) may be included, or they may take a different form (e.g., slots, slits, or other opening or aperture configurations). Other alternatives will be apparent to those of skill in this art. 
         [0038]    Referring now to  FIG. 8 , another adapter according to embodiments of the invention, designated broadly at  130 , is shown therein. The adapter  130  is similar to the adapter  30  in that it includes an outer shell  160  and an inner core  140 , but the inner core  140  has only an inner ring  142  (i.e., it has no outer ring); hence, the outer shell  160  requires no through holes. The inner ring  142 , which includes teeth  144 , is formed of softer material than the outer core  160 . 
         [0039]    The inner core  140  is attached to the outer shell  160  via a two-step injection molding process as described above; alternatively, the inner core  140  may be attached via adhesives or other fastening techniques. The adapter  130  may be more straightforward to injection mold than the adapter  30 . 
         [0040]      FIG. 9  illustrates another embodiment of an adapter, designated broadly at  230 . The adapter  230  includes an inner core  240  with teeth  244  that is similar to the inner core  140  described above. The adapter  230  also includes an outer shell  260  that is formed of two mating “clamshell” pieces  261 ,  262  of a harder material than that of the inner core  240 . As seen in  FIG. 9 , each of the clamshell pieces  261 ,  262  (which in this embodiment are substantially identical) has a stepped profile with a raised semicircular wall  264 ,  265 , which enables the pieces  261 ,  262  to mate with each other. A groove  270 ,  271  is located in each wall  264 ,  265  that receives a tab  248  that extends radially outwardly from the inner core  240 . The interaction between the tab  248  and the grooves  270 ,  271  connects the clamshell pieces  261 ,  262  with the inner core  240 . 
         [0041]    Notably, each of the clamshell pieces  261 ,  262  includes a respective thread  266 ,  268  that extends for most of the circumference of the piece  261 ,  262 . Formation of the outer core  260  in two pieces  261 ,  262  enables each of the threads  266 ,  268  to be formed in a straightforward manner in a reciprocating injection molding operation, thereby eliminating the benefit of the quarter threads discussed above in connection with the adapters  30 ,  130 . The inner core  240  can be molded onto one of the clamshell pieces  261 ,  262  prior to assembly or molded separately and inserted between the clamshell pieces  261 ,  262  prior to assembly. 
         [0042]    Referring now to  FIG. 10 , another adapter according to embodiments of the invention, designated broadly at  330 , is illustrated therein. The adapter  330  is a single piece component that includes an outer ring  332  and an inner ring  334  connected at one end by a bridge  336 , such that a gap  338  is formed between the outer and inner rings  332 ,  334 . Threads  340  extend radially inwardly from the inner surface of the inner ring  334 . 
         [0043]    The adapter  330  is typically formed of a material that has the softness to form a seal with the threaded stem of the mounting structure to which it is attached, and the rigidity to provide integrity to the joint. However, the material should also be selected to enable the inner ring  334  to flex outwardly (i.e., into the gap  338 ) so that the adapter  330  with its threads  340  can be removed from an injection mold after molding. Exemplary materials include thermoplastic elastomer (TPE) and ethylene propylene diene monomer (EPDM) rubber. 
         [0044]    An alternative adapter  330 ′ is shown in  FIG. 11 . The adapter  330 ′ is identical to the adapter  330 , but includes a soft, pliable material  342  (such as a silicone elastomer or the like) that at least partially fills the gap  340 . Filling the gap  340  can prevent water or other environmental agents from pooling in the gap  340  after the adapter  330 ′ is installed in the field. 
         [0045]    The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.