Abstract:
A connector interface includes: a first connector having an outer body with a first bearing surface facing in a first axial direction; a second connector having an outer body with a second bearing surface facing in a second axial direction opposite the first axial direction; a resilient sealing element disposed between the first and second bearing surfaces; and a coupling nut associated with the first connector and configured to engage a feature on the second connector. Rotation of the coupling nut relative to the first and second connectors draws the first and second bearing surfaces toward each other to compress the sealing element such that the sealing element bulges radially outwardly to engage an inner surface of the coupling nut.

Description:
RELATED APPLICATION 
     The present application claims priority from and the benefit of U.S. Provisional Patent Application No. 62/367,853, filed Jul. 28, 2016, the disclosure of which is hereby incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed generally to electrical cable connectors, and more particularly to coaxial connectors for electrical cable. 
     BACKGROUND OF THE INVENTION 
     Latest developments in technology for delivering power and data in wireless infrastructure use hybrid cables, wherein the term “hybrid cable” is intended to mean a cable that includes both power conductors and one or more fiber optic cords or cables. An exemplary hybrid cable is the HFF cable, available from CommScope, Inc. (Joliet, Ill.). Unlike RF-based systems, a single hybrid trunk cable can be used to power multiple sectors, thereby eliminating multiple runs of RF cable. 
     In order to use a single hybrid trunk cable, at some point the trunk cable must transition to jumper cables. Typically, these are distributed inside an enclosure that transitions the trunk conductor gauge to the jumper conductor gauge and connects the optical fibers in the trunk to the optical fibers in the jumper cables. Exemplary enclosures are described in U.S. patent application Ser. No. 14/448,269, filed Jul. 31, 2104, and Ser. No. 15/071,620, filed Mar. 16, 2016, the disclosure of each of which is hereby incorporated herein in its entirety. The enclosures discussed therein employ hybrid power/fiber connectors (also called “multi-media” connectors) that are connected with hybrid jumper cables. 
     Because they are often employed outdoors (e.g., at the top of an antenna tower), hybrid connectors include sealing elements (such as gaskets, O-rings and the like) to maintain watertightness at the interface. The inclusion of sealing elements can increase the cost of the connectors. It may be desirable to provide additional designs for connectors that provide sealing capability. 
     SUMMARY 
     As a first aspect, embodiments of the invention are directed to a connector interface, comprising: a first connector having an outer body with a first bearing surface facing in a first axial direction; a second connector having an outer body with a second bearing surface facing in a second axial direction opposite the first axial direction; a resilient sealing element disposed between the first and second bearing surfaces; and a coupling nut associated with the first connector and configured to engage a feature on the second connector. Rotation of the coupling nut relative to the first and second connectors draws the first and second bearing surfaces toward each other to compress the sealing element such that the sealing element bulges radially outwardly to engage an inner surface of the coupling nut. 
     As a second aspect, embodiments of the invention are directed to a connector interface, comprising: a first connector having an outer body with a first bearing surface facing in a first axial direction; a second connector having an outer body with a second bearing surface facing in a second axial direction opposite the first axial direction, the second connector being mounted to an enclosure, wherein each of the first and second connectors includes a plurality of optical fibers and a plurality of electrical conductors; a resilient sealing element disposed between the first and second bearing surfaces; and a coupling nut associated with the first connector and configured to engage a feature on the second connector. Rotation of the coupling nut relative to the first and second connectors draws the first and second bearing surfaces toward each other to compress the sealing element such that the sealing element bulges radially outwardly to engage an inner surface of the coupling nut. 
     As a third aspect, embodiments of the invention are directed to a connector interface, comprising: a first connector having an outer body with a first bearing surface facing in a first axial direction; a second connector having an outer body with a second bearing surface facing in a second axial direction opposite the first axial direction, the second connector being mounted on an enclosure, wherein each of the first and second connectors includes a plurality of optical fibers and a plurality of electrical conductors; a resilient scaling element disposed between the first and second bearing surfaces; and a coupling nut associated with the first connector and configured to engage a feature on the second connector. Rotation of the coupling nut relative to the first and second connectors draws the first and second bearing surfaces toward each other to compress the sealing element such that the sealing element bulges radially outwardly to engage an inner surface of the coupling nut. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a cross-section of a pair of mated hybrid power/fiber connectors according to embodiments of the invention, with the conductors removed for clarity. 
         FIG. 2  is a cross-section of the pair of mated hybrid power/fiber connectors of  FIG. 1 , with the conductors included. 
         FIG. 3  is a perspective view of the coupling nut of one of the connectors of  FIG. 1 . 
         FIG. 4  is an enlarged partial cross-section of a mated pair of hybrid connectors similar to those of  FIG. 1 , with the connectors shown in an engaged condition with the coupling nut loosened such that the sealing element is relaxed. 
         FIG. 5  is an enlarged partial cross-section of the hybrid connectors of  FIG. 4 , with the connectors shown in an engaged condition with the coupling nut tightened to compress the sealing element. 
         FIGS. 6A and 6B  are cross-sections of alternative sealing elements according to embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     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 in the below description 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. 
     Referring now to  FIGS. 1 and 2 , two mated hybrid connectors  10 ,  110  that form an interface  5  are shown therein. Each of the hybrid connectors  10 ,  110  includes a respective outer body  34 ,  134 . Power conductor contacts  32 ,  132  (shown in  FIG. 2 ) and fiber optic adapters  33 ,  133  (shown in  FIGS. 1 and 2 ) are present within their respective outer bodies  34 ,  134 . The outer body  34  has an annular mating ring  36  that extends forwardly; the outer body  134  has an annular groove  136  that receives the mating ring when the connectors  10 ,  110  are mated. A radially-outwardly-extending nub  139  is positioned near the end of the free end  138  ( FIG. 1 ) of the outer body  134 . 
     A coupling nut  60  encircles the outer body  34 . The coupling nut  60  includes three angled slots  62  ( FIG. 3 ) on its inner surface, each of which extends approximately 120 degrees. 
     As can be seen in  FIGS. 1 and 2 , an annular sealing element  54  (typically formed of a resilient material such as silicone) is located radially inwardly of the coupling nut  60 . A shallow recess  52  is present in the outer body  34  to receive the sealing element  54 . A radially-extending bearing surface  58  on the outer body  34  is adjacent the sealing element  54 . 
     As can be seen in  FIGS. 1 and 2 , in the mated condition, the mating ring  36  extends forwardly from the outer body  34  into the groove  136  (an o-ring  140  provides a seal at the floor of the groove  136 ). The free end  138  of the outer body  134  has a bearing surface  142  that contacts the sealing element  54 . Thus, the sealing element  54  is sandwiched between the bearing surface  142  of the connector  110  and the bearing surface  58  of the connector  10 . 
     Once the connectors  10 ,  110  are mated, the coupling nut  60  is rotated until one of the angled slots  62  aligns with the nub  139 . After the nub  139  slips into the slot  62 , continued rotation of the coupling nut  60  forces the connectors  10 ,  110  toward each other. This movement continues until the nub  138  reaches the end of the slot  62 , where a recess  64  can capture the nub  138  and prevent counter-rotation that could loosen the nut  60 . 
     As can be seen in  FIG. 4  (in a slightly modified embodiment), prior to the tightening of the coupling nut  60 , the sealing element  54  is in a relaxed, undeflected condition ( FIG. 4  shows the sealing element  54  as having a rectangular cross-section when relaxed). However, as the coupling nut  60  is tightened, the bearing surfaces  142 ,  58  are drawn toward each other, with the result that the sealing element  54  is compressed. As a consequence of this axial compression, the sealing element  54  expands or bulges radially outwardly to contact the inner surface of the coupling nut  60  (see  FIG. 5 ). 
     The radially outward expansion of the sealing element  54  can provide two different functions. First, by contacting the inner surface of the coupling nut  60 , the bulging sealing element  54  can provide a seal between the inner surface of the coupling nut  60  and the sealing element  54 . Second, the bulging of the sealing element  54  into contact with the inner surface of the coupling nut  60  can provide friction that prevents unwanted loosening of the coupling nut  60 . 
     In the illustrated embodiment, the connector  110  is mounted to the wall of an enclosure (such as that described above) for distributing the optical fibers and conductors of a hybrid trunk cable. The connector  10  is connected with a hybrid jumper cable (not shown). However, those skilled in this art will appreciate that the connectors  10 ,  110  may be attached to or mounted on other components; for example, both connectors may be attached to cables, or both connectors may be mounted on equipment (for example, on a remote radio unit (RRU) that is attached to an antenna). 
     Those skilled in this art will also appreciate that the sealing element may take different forms. Although the sealing element  54  has a generally rectangular cross-section, other shapes may be possible, such as the trapezoidal shape  54 ′ shown in  FIG. 6A , the hourglass shape  54 ″ shown in  FIG. 6B , and the like. Due to the presences of their angled surfaces that engage the bearing surfaces of the connectors, both the trapezoidal and hourglass shapes may tend to bulge radially outwardly under axial compression. 
     Also, as shown in  FIGS. 4 and 5 , it may be beneficial for one or both of the bearing surfaces  58 ,  142  to have a protrusion (shown at  70  in  FIGS. 4 and 5 ) that encourages radially-outward bulging. A similar effect may be achieved by angling one or both of the bearing surfaces  58 ,  142 . 
     Further, those of skill in this art will appreciate that other types of connectors may benefit from the concepts discussed herein. For example, coaxial connectors and fiber optic adapters/connectors that rely on a rotating nut for connection may also be suitable. Also, the coupling nut may have any variety of threads or slots that cause the nut to advance axially during rotation of the nut. 
     While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant&#39;s general inventive concept. Further, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.