Patent Publication Number: US-10312629-B2

Title: Coaxial connector with inhibited ingress and improved grounding

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 14/884,385, filed Oct. 15, 2015, which is a continuation of U.S. application Ser. No. 13/084,099, which granted as U.S. Pat. No. 9,166,348 B1, was filed Apr. 11, 2011, and which claims the benefit of, and priority to, U.S. Provisional Patent Application Ser. No. 61/323,597, filed on Apr. 13, 2010. The contents of these applications are incorporated herein by reference in their entirety. This application is related to U.S. application Ser. No. 14/329,093, filed Jul. 11, 2014, which is a division of U.S. application Ser. No. 13/084,099, filed Apr. 11, 2011, and is now abandoned. 
    
    
     BACKGROUND 
     Field 
     The disclosure relates generally to coaxial cable connectors, and particularly to coaxial cable connectors capable of connecting a coaxial cable to a terminal. 
     Technical Background 
     With the advent of digital signal in CATV systems, a rise in customer complaints due to poor picture quality in the form of signal interference resulting in what is known as “tiling” and the like has occurred. Complaints of this nature result in CATV system operators having to send a technician to address the issue. Frequently, it is reported by the technician that the cause of the problem is a loose F connector fitting. Type F connector fittings may be loose for many reasons, sometimes they are not properly tightened due to installation rules of system operators that prohibit the use of wrenches in-doors on customer equipment. Other times, a homeowner may relocate equipment after the technician departs and may not adequately secure the F connectors. Additionally, some claim that F connector couplers loosen due to vibration and/or heat and cold cycles. 
     In any event, an improperly installed connector may result in poor signal transfer because there are discontinuities along the electrical path between the devices, resulting in a leak of radio frequency (“RF”) signal. That leak may be in the form of signal egress where the RF energy radiates out of the connector/cable arrangement. Alternately, an RF leak may be in the form of signal ingress where RF energy from an external source or sources may enter the connector/cable arrangement causing a signal to noise ratio problem resulting in an unacceptable picture. 
     F connectors typically rely on intimate contact between the F male connector interface and the F female connector interface. If for some reason, the connector interfaces are allowed to pull apart from each other, such as in the case of a loose F male coupler, an interface “gap” may result. This gap can be a point of an RF leak as previously described. Typically, in such situations where the F male coupler is loose, the configuration allows for two distinct signal ingress paths. One path is found from the “back” of the F male coupler between the coupler bore and connector body. When the coupler is loosened, the connector body is permitted to move about, creating gaps that were previously secured when the connection was tight. Typically, these gaps allow a signal path along a relatively straightforward line. The other path is found at the “front” of the F male coupler along the spiral path of the interconnecting thread system. In the loose condition, tolerances in the thread system allow signal ingress because the flanks of the treads are not intimately engaged enough to provide adequate shielding. 
     To at least partially address the signal ingress and grounding issues, a number of approaches have been introduced, including U.S. Pat. No. 7,114,990 (Bence, et al.); U.S. Pat. No. 7,479,035 (Bence, et al.); U.S. Pat. No. 6,716,062 (Palinkas, et al.) and US Patent application 2008/0102696 (Montena). In addition, other approaches have been introduced to at least partially address the issue of loosening Type F couplers, including a lock-washer design produced by Phoenix Communications Technologies International (PCT) known at the DRS and TRS connectors. However, there is a continuing need for improved connector designs that address theses issues simultaneously. 
     SUMMARY 
     One embodiment of the disclosure relates to a coaxial connector for coupling an end of a coaxial cable to a terminal. The coaxial connector includes a hollow body having a front end, a rear end, and an internal surface extending between the front end and the rear end, the internal surface defining a longitudinal opening. The coaxial connector also includes a tubular post disposed at least partially within the longitudinal opening of the hollow body. The tubular post includes a front end, a rear end, a tubular shank adjacent to the rear end, and a flange adjacent to the front end, wherein the flange has an outer diameter that is larger than the outer diameter of the tubular shank. In addition, the coaxial connector includes a coupling nut having a front end, and a rear end, and a radially inward directed collar with a circular aperture formed therein. The circular aperture has a diameter that is less than the outer diameter of the flange of the tubular post and a front end facing surface of the radially inward directed collar rotationally engages a rear end facing surface of the flange of the tubular post. The coaxial connector further includes a sealing member disposed between a rear end facing surface of the radially inward directed collar and a front end facing surface of the hollow body. The sealing member is axially compressed by the rear end facing surface of the radially inward directed collar and the front end facing surface of the hollow body. 
     Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims. 
     The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a partial cross sectional view of a prior art connector in a state of proper engagement with a terminal or port; 
         FIG. 2  illustrates a partial cross sectional view of the connector illustrated in  FIG. 1  in a state of improper engagement (otherwise known as “loose”) with a terminal or port; 
         FIG. 3  illustrates a partial cross sectional view of an alternative prior art connector in an uninstalled condition to illustrate o-ring utilization; 
         FIG. 4  illustrates a partial cross sectional view of a connector disclosed herein installed on a coaxial cable; 
         FIG. 4A  illustrates an enlarged view of a portion of the connector illustrated in  FIG. 4 ; 
         FIG. 5  illustrates a partial cross sectional view of the connector of  FIG. 4  installed on a coaxial cable and fully secured to a terminal or port; 
         FIG. 6  illustrates a partial cross sectional view of the connector of  FIG. 4  installed on a coaxial cable and partially secured to a terminal or port; 
         FIG. 7  illustrates a partial cross sectional view of an alternate embodiment of a connector comprising an alternate ground member and installed on a coaxial cable and fully secured to a terminal or port; 
         FIG. 7A  illustrates side perspective and schematic end views of the alternate ground member shown on the connector illustrated in  FIG. 7 ; 
         FIG. 8  illustrates a partial cross sectional view of an alternate embodiment of a connector comprising a coupling nut having an offset thread and installed on a coaxial cable and fully secured to a terminal or port; 
         FIG. 8A  illustrates a posterior schematic end view of the connector illustrated in  FIG. 8 ; 
         FIG. 9  illustrates a partial cross sectional view of the connector of  FIG. 4  with an optional torque aid installed; 
         FIG. 10  illustrates a schematic end view of the optional torque aid illustrated in  FIG. 9 ; 
         FIG. 11  illustrates a partial cross sectional view of an alternate embodiment of a connector comprising a modified post; 
         FIG. 11A  illustrates an anterior schematic end view of the post illustrated in  FIG. 11 ; 
         FIG. 12  illustrates a partial cross sectional view of an alternate embodiment of a connector comprising a sealing member disposed between the coupler, post, and body; 
         FIG. 13  illustrates a partial cross sectional view of an alternate embodiment of a connector having a coupling nut having a radially inwardly biased front end and a plurality of slots; and 
         FIG. 14  illustrates a schematic front end view of an alternate embodiment of a coupling nut having an at least partially unrounded inner surface. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to embodiments of coaxial connectors, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
     Referring to  FIG. 1 , a prior art coaxial connector  10  has a coupling nut  20 , a post  30 , a body  50 , and a compression ring  55 . The coaxial connector  10  is an axial-compression type coaxial connector and the connection of the coaxial connector  10  to a coaxial  11  cable is known in the art. The coaxial connector  10  is illustrated in  FIG. 1  in its attached, compressed state. When properly tightened to port  40 , the gap “G” between post face  32  and port face  42  is completely closed. In other words, post face  32  and port face  42  are in intimate contact. 
       FIG. 2  illustrates coaxial connector  10  and port  40  of  FIG. 1 , wherein coupling nut  20  of connector  10  is not fully tightened thereby allowing post face  32  and port face  42  to be spaced apart at gap “G”. The resultant gap “G” and clearances between internal features of coupler  20  and body  50  result in a relatively unobstructed ingress path “P 1 ”. RF (Radio Frequency) signal ingress travels along this path into the connector interface allowing undesirable electrical interference. The RF ingress path is unimpeded by non-conductive materials such as o-ring  57 . A secondary ingress path “P 2 ” is created when the internal threaded portion of coupler  20  is not loaded against external threaded portion of port  40 . Said secondary ingress path “P 2 ” is abetted by relatively large mechanical clearances between pilot bore  21  of coupler  20  and external surfaces of port  42 . Body  50  and post  30  of connector  10  are permitted to angle away from a fully axial alignment with port  42  causing body  50  and post  30  to have limited, incidental contact with coupler  20  resulting in an undependable, limited number of points electrical ground path. 
       FIG. 3  illustrates a partial cross sectional view of an alternative prior art connector in an uninstalled condition illustrating o-ring utilization known and practiced in the art. O-ring  80  is compressed radially as illustrated at “A” (as opposed to being compressed axially) and is conventionally used as a moisture barrier. O-ring  80  is allowed axial clearance in order to ensure rotatability of coupler  120 . This necessary clearance allows limited axial movement of coupler  120  and permits gapping between annular shoulder  121  of coupler  120  and annular shoulder  122  of post  123 . Said gapping results in a situation for a relatively unobstructed ingress path as previously described. 
       FIG. 4  illustrates a partial cross sectional view of a coaxial connector  150  as disclosed herein installed on a coaxial cable  11 . Coaxial connector  150  includes coupling nut  160 , post  170 , sealing member  180 , and body  190 . Coupling nut  160 , post  170 , and body  190  are preferably made from a metallic material, such as brass and may optionally be plated with a conductive, corrosion-resistant material, such as nickel or tin. 
     Body  190  is preferably a hollow body having a front end  192 , a rear end  194 , and an internal surface (not shown) extending between the front and the rear end, wherein the internal surface defines a longitudinal opening. 
     Post  170  is preferably a tubular post disposed at least partially within the longitudinal opening of the body  190 . Post  170  includes a front end  172  (including a forward facing post face), a rear end, ( )  202 , a tubular shank  200  adjacent to the rear end ( )  202 , and a flange  174  adjacent to the front end  172 , wherein the flange  174  has an outer diameter that is larger than the outer diameter of the tubular shank  200 . 
     Coupling nut  160  includes a front end  162 , and a rear end  164 , and a radially inward directed collar  166  with a circular aperture formed therein. The circular aperture formed in the radially inward directed collar  166  has a diameter that is less than the outer diameter of the flange  174  of the post  170 . A front end facing surface  165  of the radially inward directed collar  166  rotationally engages a rear end facing surface  175  of the flange  174  of the post  170 . 
     Sealing member  180  is disposed between a rear end facing surface  163  of the radially inward directed collar  166  and a front end facing surface  195  of the body  190 . Sealing member  180  is preferably an o-ring that is preferably made from an elastomer material, such as EPDM (Ethylene Propylene Diene Monomer). 
     As illustrated in  FIG. 4 , internal features of coupling nut  160  and body  190  define an annular space to house sealing member  180 . This annular space is configured to pre-load sealing member  180  in an axial fashion indicated by “A” (in contrast to prior art utilization of the o-ring as illustrated in  FIG. 3 ). Alternatively stated, sealing member  180  is axially compressed by the rear end facing surface  163  of the radially inward directed collar  166  and the front end facing surface  195  of the body  190 . While the sealing member  180  performs an environmental sealing function, it now also serves to urge coupling nut  160  forward against post flange  174  to aid in electrical grounding. This, in conjunction with precision engineered fits between coupling nut  160 , post  170 , and body  190  restricts RF signal ingress paths from the rear of the connector coupler system. The increased convoluted RF ingress path “P” defined by the juxtaposition of coupling nut  160 , post  170 , and body  190  serves as a further barrier against RF signal ingress. 
     As further illustrated in  FIG. 4 , front end  192  and front end facing surface  195  of body  190  have a larger outer diameter than an outer diameter of the sealing member  180 . In addition, to the rear of the radially inward directed collar  166 , the coupling nut  160  includes a rearward extending annular portion  168  having a circular aperture formed therein. The circular aperture in the rearward extending annular portion  168  has a diameter that is greater than the circular aperture formed in the radially inward directed collar  166  and at least a portion of an inner surface of the rearward extending annular portion  168  contacts and circumferentially surrounds at least a portion of an outer surface of the body  190 . Preferably, the circular aperture in the rearward extending annular portion  168  of the coupling nut  160  and the portion of the body  190  that is circumferentially surrounded by the rearward extending annular portion  168  of the coupling nut  160  each have an outer diameter that is greater than the outer diameter of the flange  174  of the post  170 . Preferably, sealing member  180  also has an outer diameter that is greater than the outer diameter of the flange  174  of the post  170 . Preferably, an outer diameter of the sealing member  180  does not contact the inner surface of the rearward extending annular portion  168  of the coupling nut  160  and an annular gap extends between the outer diameter of the sealing member  180  and the inner surface of the rearward extending annular portion  168  of the coupling nut  160 . Annular gap allows for sealing member  180  to flex radially outwardly as it is being compressed axially. 
     In the embodiment illustrated in  FIG. 4 , sealing member  180  that is axially compressed by the rear end facing surface  163  of the radially inward directed collar  166  and the front end facing surface  195  of the body  190  does not contact post  170  (as opposed to the embodiment illustrated in  FIG. 12  and described below). 
     Preferably, and as illustrated in  FIG. 4 , the portion of the body  190  that is circumferentially surrounded by the rearward extending annular portion  168  of the coupling nut  160  comprises a plurality of contact points  196  on its outer surface, wherein at least a portion of an outer surface of the contact points contact the inner surface of the rearward extending annular portion  168  of the coupling nut  160 . For example, in a preferred embodiment, the contact points  196  comprise radially outwardly extending geometrically shaped projections, such as diamond-shaped, square-shaped, or circular-shaped projections. In a particularly preferred embodiment, and as illustrated in  FIG. 4 , the contact points  196  on the outer surface of body  190  comprise a knurled outer surface. 
     Post flange  174  also preferably comprises a plurality of contact points  177  on its outer surface, wherein at least a portion of an outer surface of the contact points contact an inner surface of the coupling nut  160 . For example, in a preferred embodiment, the contact points  177  comprise radially outwardly extending geometrically shaped projections, such as diamond-shaped, square-shaped, or circular-shaped projections. In a particularly preferred embodiment, and as illustrated in  FIG. 4 , the contact points  177  on the outer surface of post flange  174  comprise a knurled outer surface. An enlarged view of these features is illustrated in  FIG. 4A . 
     Formation of radially outwardly extending geometrically shaped projections as contact points about post flange  174  and body  190  by knurling or other means provides for increased contact pressure between the radial features of the connector components when the connector is in a loose condition (as illustrated, for example, in  FIG. 6 ) further restricting RF signal ingress paths from the rear of the connector coupler system. Contact points  177  and/or  196  further serve to disrupt RF signal ingress by dispersing spurious RF signals in a manner roughly analogous to the use of LO technology (low observable technology) multi-planar surfaces employed on radar reflecting ships and aircraft. A further analogy to this approach is found in RF anechoic chamber technology. 
       FIG. 5  illustrates a partial cross sectional view of the connector  150  illustrated in  FIG. 4  installed on a coaxial cable and fully secured to a terminal or port  40 . In this condition, all ingress paths are fully shielded as provided by application of proper torque to connector coupler  160 . 
     Turning to  FIG. 6 , the connector  150  illustrated in  FIG. 4  and port  40  are illustrated where coupler  160  of connector  150  is not fully tightened thereby allowing post front end  172  (including post face) and port face  42  to be spaced apart at gap “G”. As previously described, sealing member  180  performs not only an environmental sealing function but also serves to urge coupler  160  forward against post flange  174  to aid in electrical grounding. This, in conjunction with precision engineered fits between coupling nut  160 , post  170  and body  190 , restricts RF signal ingress paths from the rear of the connector coupler system. Forming of a plurality of contact points  177  about post  170  and a plurality of contact points  196  about body  190  by knurling or other means provides for increased contact pressure between the radial features of the connector components when the connector is in a loose condition as illustrated. The RF signal ingress path is further thwarted by the increased convolutions of the coupler/body/post configuration. This is especially useful in that RF signals tend to attenuate when presented by multiple, sharp changes in direction as provided herein. Additional thwarting of the RF ingress path on the port side of the coupler system is accomplished by restricting or choking the diametral clearances between inner bore of the front end of the coupling nut (or pilot bore  167 ) and major diameter port threads  44  of port  40 . Further thwarting of the RF ingress path on the port side of the coupler system is accomplished by restricting or choking the diametral clearances between threads  169  of coupler  160  and minor diameter port threads  44  of port  40 . 
       FIG. 7  illustrates a partial cross sectional view of an alternate embodiment of a connector  150  comprising an electrically conductive ground member  300  and installed on a coaxial cable  11  and fully secured to a terminal or port  40 . Ground member  300  is preferably press-fitted into pilot bore  167  of coupling nut  160  and comprises a plurality of radially inwardly biased fingers that provide electrical and mechanical communication between coupling nut  160  and port  40 . The ground member  300  is preferably made from a metallic material, such as beryllium copper and may optionally be plated with a conductive, corrosion-resistant material, such as tin. Alternatively, the ground member  300  may be a coil-type spring or alternatively, the ground member  300  may be an electrically conductive elastomer. 
       FIG. 7A  illustrates side perspective and schematic end views of electrically conductive ground member  300  including radially inwardly biased fingers  303 . Ground member  300  may, as shown in  FIG. 7A , be c-shaped and include an optional radially extending slot  301 . Alternatively, ground member  300  may entirely circumferentially surround pilot bore  167  (not shown). 
       FIG. 8  illustrates a partial cross sectional view of an alternate embodiment of a connector  150 ′ comprising a coupling nut having an offset inner thread  161  and installed on a coaxial cable  11  and fully secured to a terminal or port  40 . Offset inner thread  161  is built into coupling nut  160 ′ at an axis parallel to the center axis of coupling nut  160 ′ but radially displaced from the center axis of coupling nut  160 ′ such that the annular thickness of the coupling nut  160 ′ between an inner surface and an outer surface varies circumferentially around the coupling nut  160 ′. For example, as illustrated in  FIG. 8 , the annular thickness of coupling nut  160 ′ at A′ is greater than the annular thickness of coupling nut  160 ′ at B′. Preferably, the coupling nut  160 ′ has an annular thickness that varies circumferentially around pilot bore  167  (see  FIG. 8A , showing a posterior schematic end view of the connector illustrated in  FIG. 8 ) such that the largest annular thickness of the coupling nut  160 ′ around pilot bore  167  is at least 10%, more preferably at least 20%, and even more preferably at least 30% greater than the smallest annular thickness of coupling nut  160 ′ around pilot bore  167 . This has the effect of purposely misaligning connector  150 ′ with port  40  forcing the cable center conductor (not shown) into a side-loaded condition. In this side-loaded condition, the copper coated steel center conductor is forced to act as a spring and thereby apply a force that enhances radial contact between threads of coupling nut  160 ′ and thread  44  of port  40  ensuring an electrical ground path. 
       FIG. 9  illustrates a partial cross sectional view of connector  150  and an optional torque aid  400 , wherein the torque aid  400  is installed on the connector  150  and is in contact with and circumferentially surrounds at least a portion of coupling nut  160 .  FIG. 10  illustrates a schematic end view of torque aid  400 . Torque aid  400  is preferably made from a plastic material, such as acetal, and allows for the connector to be more adequately installed onto a port in limited accessibility situations by providing for improved finger grip on the coupler system. As shown in  FIG. 10 , torque aid  400  includes internal hex  465  which is configured to engage external hex  165 A of coupling nut  160  while internal ridge  468  engage grooves  168 A of coupling nut  160 . Optional radially extending slot  467  allows torque aid  400  to snap over and onto coupling nut  160 . A plurality of optional external gripping surfaces  469  provide for enhanced finger grip. Torque aid  400  is of further benefit in reducing the manufacturing cost of coupling nut  160  by eliminating the need to produce coupling nut  160  from a larger material stock size as seen in Corning Gilbert Connector GF-UR-6K currently produced for the industry. 
       FIGS. 11 and 11A  illustrate an alternate embodiment, wherein  FIG. 11  illustrates a partial cross sectional view of a connector comprising a modified post  170 ′ and  FIG. 11A  illustrates a schematic end view of modified post  170 ′. Modified post  170 ′ comprises radial knurl  179  on rear end facing surface  175  of post flange  174  that provides high pressure contact points between front end facing surface  165  of radially inward directed collar  166  of coupling nut  160  and crests of radial knurl  179 . Reducing the square inches of contact area between the surfaces increases contact pressures in PSI (pounds per square inch) when the same load is applied by the coupler system. Such increased contact pressures enhance electrical grounding characteristics. 
       FIG. 12  illustrates a partial cross sectional view of an alternate embodiment of a connector  150 ″ wherein sealing member  180  is disposed between the coupling nut  160 , post  170 , and body  190 ″, such that an inner surface of the sealing member  180  contacts post  170  (in contrast to the connector illustrated in  FIG. 4 , wherein an inner surface of the sealing member  180  contacts body  190 ). 
       FIG. 13  illustrates a partial cross sectional view of an alternate embodiment of a connector  150 ′″, wherein coupling nut  160 ′″ has a front end that is formed or biased radially inwardly and front end of coupling nut  160 ′″ includes a plurality of slots  161 ′″ extending from the front end of the coupling nut between an inner and an outer surface of the front end of the coupling nut  160 ′″. The radially inwardly biased front end of coupling nut  160 ′″ help insure that the threads of the coupling nut  160 ′″ contact a mating port (not shown) and the slots allow for spring or flex back functionality to facilitate mating of the threads of the coupling nut with threads on a mating port (not shown). 
       FIG. 14  illustrates a schematic front end view of an alternate embodiment of a coupling nut  160 ″″ that can be used with one or more embodiments of connectors described herein, wherein the front end of coupling nut  160 ″″ has an at least partially unrounded surface. Preferably, the at least partially unrounded surface is an inner surface on the front end of the coupling nut  160 ″″ although, as shown in  FIG. 14 , both inner and outer surfaces on front end of coupling nut may be unrounded. By “unrounded” it is meant that the front end of the coupling nut includes one or more intentionally introduced deformations wherein the deformations result in the front end of the coupling nut  160 ″″ having inner and/or outer surfaces that are not perfectly circular when viewed head on from the front end. For example,  FIG. 14  illustrates a coupling nut  160 ″″ having a front end with intentionally introduced deformations shown as a plurality of flat spots  168 ″″ (flat spots  168 ″″ are shown in an exaggerated fashion for the purposes of illustration). The at least partially unrounded inner surface allow for the threads of the coupling nut  160 ′″ to more positively contact a mating port (not shown). 
     Coaxial connectors disclosed herein can, in preferred embodiments, mitigate the effect of gapping at the connector/port interface, provide an alternative ground path, provide a means to protect from signal ingress and egress, and help ensure against further loosening of an unsecured coupler. 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred. 
     It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the invention. Since modifications combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.