Abstract:
A port terminator includes an outer nut, which may be either electrically conductive or non-electrically conductive, and an electrically conductive ground insert. A portion of the ground insert captures a ground portion of a termination resistor, while a deformable portion of the ground insert makes electrical contact with a connection end of an equipment port when the port terminator is screwed onto the equipment port. The deformable portion can take the form of a flexible brim or a plurality of petals. The petals preferably alternate between flat petals and biased petals. The ground insert permits the port terminator to make a uniform RF seal on an equipment port even with a range of tightening torques.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of and claims priority from U.S. patent application Ser. No. 12/140,573 filed on Jun. 17, 2008, now U.S. Pat. No. 7,753,705 and entitled FLEXIBLE RF SEAL FOR COAXIAL CABLE CONNECTOR, which is a continuation of and claims priority from U.S. application Ser. No. 11/553,115 filed Oct. 26, 2006 and entitled FLEXIBLE RF SEAL FOR COAXIAL CABLE CONNECTOR, now, abandoned, both of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to the field of CATV port terminators, and more particularly to a port terminator which incorporates a contact-enhancing ground insert for a termination resistor. 
     BACKGROUND OF THE INVENTION 
     CATV systems continue to be plagued with service quality problems resulting from loose connections. For the most part, these connectors are loose because they were not installed to the proper torque, which can occur for a number of reasons from laziness, a lacking of training, and improper use of/inadequate tools. An improperly installed connector will result in poor signals, because there are gaps between the devices, resulting in a leak of radio frequency (“RF”) signal. 
     As an example, a cable port is used to transfer an RF signal to a coaxial cable that transmits the signal to video equipment, such as a television. The coaxial cable has, attached to its terminal end, a female cable connector, which is used to house the cable and assist its connection to a cable port. The connector contains a nut that engages the cable port and advances the connector with a coaxial cable to the port. In this instance, the cable connector nut is used to hold two mating surfaces, the cable port and the cable connector housing the coaxial cable. If these two surfaces are not tightly connected, a gap will exist creating a loss in RF signal, resulting in lower quality cable signal. 
     Improvements on coaxial cable connectors have been proposed to deal with such a problem. An example of such an improvement on a connector is described in U.S. Pat. No. 6,716,062 (Palinkas, et al.), the disclosure of which is herein incorporated by reference. In this patent, a spring element is incorporated to a traditional coaxial cable connector, under a nut element and beneath the flange portion of a post member. The spring biases the connector face towards a port after the nut is rotated around the connector a certain number of times. While this device is effective, it requires time and cost in the manufacturing process of the connector. 
     In addition, in high density urban CATV systems, it is often common practice to place equipment, such as taps, based on the total housing density instead of the actual subscriber density. In some countries, such as Great Britain, this is required by law, resulting in 100 taps installed for a 100-dwelling apartment building even if there are only 30 CATV subscribers. As a result, it is not unusual for there to be unused ports, particularly in systems with low penetration. When unused ports are left unterminated, or are terminated with port connectors which are easily left loose by the installer, or which become loose with the vibrations common to an urban environment, significant degradation to CATV service occurs. 
     SUMMARY OF THE INVENTION 
     Briefly stated, a port terminator includes an outer nut, which may be either electrically conductive or non-electrically conductive, and an electrically conductive ground insert. A portion of the ground insert captures a ground portion of a termination resistor, while a deformable portion of the ground insert makes electrical contact with a connection end of an equipment port when the port terminator is screwed onto the equipment port. The deformable portion can take the form of a flexible brim or a plurality of petals. The petals preferably alternate between flat petals and biased petals. The ground insert permits the port terminator to make a uniform RF seal on an equipment port even with a range of tightening torques. 
     According to an embodiment of the invention, a port terminator for use in a coaxial cable system includes an outer nut; the outer nut having first and second chambers; an inside of the first chamber having at least one thread therein; a ground insert positioned inside the second chamber; the ground insert being electrically conductive; the ground insert having a capture portion, a middle portion, and a deformable portion, with the capture portion connected to the middle portion, and the middle portion connected to the deformable portion via a transition band; a termination resistor including a ground portion, an insulator portion, and a conductor portion, wherein an electrical resistance is electrically connected between the conductor portion and the ground portion and surrounded by the insulator portion; and the ground portion of the termination resistor being held inside and making electrical contact with the capture portion of the ground insert. 
     According to an embodiment of the invention, a method for manufacturing a port terminator for use in a coaxial cable system includes the steps of forming an outer nut having first and second chambers; forming at least one thread on an inside of the first chamber; forming an electrically conductive ground insert, wherein the ground insert includes a capture portion, a middle portion, and a deformable portion, with the capture portion connected to the middle portion, and the middle portion connected to the deformable portion via a transition band; positioning the ground insert inside the second chamber; providing a termination resistor including a ground portion, an insulator portion, and a conductor portion, wherein an electrical resistance is electrically connected between the conductor portion and the ground portion and surrounded by the insulator portion; positioning the ground portion of the termination resistor inside the capture portion of the ground insert; and fastening the ground portion of the termination resistor to the capture portion of the ground insert, thereby making good electrical contact between the termination resistor and the ground insert. 
     According to an embodiment of the invention, a port terminator for use in a coaxial cable system includes an outer nut; the outer nut having first and second chambers; an inside of the first chamber having at least one thread therein; a ground insert positioned inside the second chamber; the ground insert being electrically conductive; a termination resistor including a ground portion, an insulator portion, and a conductor portion, wherein an electrical resistance is electrically connected between the conductor portion and the ground portion and surrounded by the insulator portion; the ground insert including means for receiving and being electrically connected to the ground portion of the termination resistor; and the ground insert further including deformable means for establishing electrical contact with a connector end of an equipment port when the port terminator is connected to the equipment port, such that an electrical path is established from a conductor port of the equipment port to the termination resistor to the ground insert to the connector end of the equipment port. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a cross-sectional view of the first embodiment of the flexible RF seal of the parent application. 
         FIG. 1B  shows an isometric view of the first embodiment of the flexible RF seal of the parent application. 
         FIG. 2A  shows a cross-sectional view of the second embodiment of the flexible RF seal of the parent application. 
         FIG. 2B  shows an isometric view of the second embodiment of the flexible RF seal of the parent application. 
         FIG. 3  shows a cross-section of the coaxial cable connector with the first embodiment of the flexible RF seal of the parent application. 
         FIG. 4  shows a cross-section of the coaxial cable connector with the second embodiment of the flexible RF seal of the parent application. 
         FIG. 5  shows a perspective view of a CATV port terminator according to an embodiment of the invention. 
         FIG. 6  shows a partially cutaway view of a CATV port terminator according to an embodiment of the invention. 
         FIG. 7  shows an exploded view of a CATV port terminator according to an embodiment of the invention. 
         FIG. 8  shows an exploded view of a CATV port terminator according to an embodiment of the invention. 
         FIG. 9  shows a partially cutaway view of a CATV port terminator according to an embodiment of the invention. 
         FIG. 10  shows a perspective view of a CATV port terminator according to an embodiment of the invention. 
         FIG. 11  shows a perspective view of an example of an equipment port. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1A and 1B , a sealing element for a coaxial cable connector  100  ( FIGS. 3-4 ) is shown. More specifically, the sealing element is designed to ensure a solid mechanical and electrical connection between a coaxial cable, connector and part, and thereby termed a flexible radio frequency (“RF”) seal  10 . There are three regions that define the flexible RF seal  10 . First, there is a flexible or resilient brim  12  that is flexible for ensuring a tight connection between a connector and a cable port (not shown) to which it is coupled. Second, there is a transition band  14 , and the band  14  transitions to a tubular insert portion  16 . The flexible RF seal  10  also has an insert chamber  18  defined within the seal  10 . 
     The flexible brim  12  is a flange end that, when inserted into a coaxial cable connector, in its first embodiment, sits above a post member, as will be shown and described in greater detail below. The flexible brim  12 , in this position, can be pressed against a coaxial port causing the flexible brim  12  to be compressed and bent so that it creates a tight connection between the connector and port. In the first embodiment of the flexible RF seal  10 , the flexible brim  12 , because of the inner geometries of the coaxial cable connector, is angled, so that it can sit within the connector and seal the connector face to the cable port. Preferably, the flexible brim  12  is seventy-degrees (70°) from the horizontal. The flexible brim  12  is shaped such that the flexible brim  12  is angled away from an insert chamber  18 . 
     The next region of the flexible RF seal  10  is the transition band  14 . Due to the shape of cable connectors in general and the positioning of the flexible RF seal within the connector, there is a band  14  that transitions the flexible brim  12  to the tubular insert portion  16 . As shown in  FIGS. 1A and 1B , the transition band  14  is a flat, inclined portion on the inside of the seal  10 . The transition band  14  assists in the flexibility of the seal  10 , in that as a transition portion it allows the flexible brim  12  to further bend or create a greater angle of distance once the flexible brim  12  is engaged by a coaxial port on one end and further compressed by a post member of a connector on its other end. 
     The last region of the flexible RF seal is the tubular insert portion  16 . The tubular insert portion  16  is below the transition band  14 . The tubular insert portion  16  is cylindrical in shape and depending on its embodiment can be used to sit on the inside or outside of a post within a coaxial cable connector. Defined within the tubular insert portion  16  is an insert chamber  18 . The tubular insert portion  16 , in the first embodiment of the flexible RF seal  10 , sits within a post member of a cable connector (as shown in  FIG. 3 ). As a result, the insert chamber  18  assists in housing a coaxial cable on which the cable connector is placed. 
     Referring to  FIGS. 2A and 2B , there is a second embodiment of the flexible RF seal, denoted by a reference numeral  20 . The flexible RF seal  20  has the same three regions as the first embodiment: a flexible brim  12 , a transition band  14 , and a tubular insert  16 . Further, defined within the flexible RF seal  20 , as with the first embodiment  10 , is an insert chamber  18 . The flexible RF seal  20  of this second embodiment has a different shape than the first embodiment  10 . The shapes are different because the seal  20  is configured to sit inside a post member instead of above the post member as is the case for the embodiment of  FIGS. 1A-1B . The flexible brim  12  is spaced such that the brim  12  is angled inward towards the insert chamber  18 . Moreover, the tubular insert  16  of the flexible RF seal  20  may generally be larger in diameter than the seal  10  because the tubular insert  16  is configured to sit outside of the post member of the coaxial cable connector. 
     The flexible RF seal  10 ,  20  can be made of any suitable material which can assist in providing a tight, solid physical and electrical connection between the surfaces of a coaxial cable connector and a cable port. Suitable materials can include metals such as beryllium copper, spring steel, and phosphor bronze, which are all resilient and allow for flexibility. Further, while the flexible RF seals  10 ,  20  are shown in with a solid, smooth surface, the seal can have a construction where there are fingered elements, or may further have a wavy construction. 
     In  FIGS. 3 and 4 , there is shown a conventional coaxial cable connector  100  that is placed on the terminal end of a coaxial cable (not shown). The connector  100  has six elements. First, there is a nut  30  on the terminal end of the connector  100  to attach connector  100 , whose other end is attached to a coaxial cable (not shown), to a cable port (not shown). The nut  30  rotates freely around a post  40 , so that it can advance the connector  100  and coaxial cable housed within it to a cable port. The nut  30  is interconnected to the post  40  under the flange end  44  of the post  40 , whereby there is a nut groove  46  created between the post  40  and a body member  60 . Specifically, the nut groove  46  is bounded by a flange end  44  of the post  40  and above an end of a body flange  62 . The corresponding nut flange  34  that fits within the nut groove  46  and allows the nut  20  to freely rotate about the connector  100 . The post  40  has a cylindrical bore defined through it to house portions of the coaxial cable. 
     Further, between the nut  30  and the body member  60  is a coupling element  90 , such as an O-ring to provide a weathertight connection between these elements. The body member  60  is also connected to the post  40  through a larger body groove  48 , in which a portion of the body flange  62  fits. Defined between the body member  60  and the post  40  is a coaxial cable material space  80 . A coaxial cable is typically made from several components. Working from the inside to the outside, the inner most part of a cable is a central conductor surrounded by an inner dielectric layer which is covered by a layer of aluminum. Outside the aluminum layer is a braided metal layer, with the entire cable then housed in another dielectric material. There is a lower separator member  50  ( FIG. 4 ) of post  40  which separates the coaxial cable between its aluminum layer and braided metallic layer, so that the outer dielectric layer and braided metal layer enter the coaxial cable material space  80 , while the aluminum layer, inner dielectric layer, and central conductor layer sit in the cylindrical bore  82  of the post  40 . At the opposite end of the connector  100  from nut  30  is a compression ring  70  which assists in attaching the connector  100  to a prepared end of the coaxial cable. 
     Referring now to  FIG. 3 , the first embodiment of the invention is shown coupled to conventional coaxial cable connector  100 . The post  40  has a lip  42  on which the flexible RF seal  10  sits. The tubular insert  16  sits within the post  40 , such that the insert chamber  18  assists in creating a continuous cylindrical bore within which a portion of a coaxial cable (not shown) would be housed. The flexible brim  12  sits above the flange end  44  of the post  40 , but is not flush with the flange end  44 . The flexible brim  12  is not flush with the flange end  44  so that it can conform to shapes of a cable port (not shown) and the connector  100 , and to a greater extent the cable housed within the connector, as sometimes there can be gaps between the cable port and the inner portions of the connector  100  with a cable. As mentioned above, the flexible brim  12  can be, if necessary, pushed backward so that the angle from the horizontal increases from its manufactured positioning. Moreover, the flexible brim  12  can be deformed to ensure an RF-tight connection between the post  40  and the cable port. 
     Referring to  FIG. 4 , the second embodiment of the seal  20  is shown coupled to connector  100 . The seal  20  sits on the outside of the flange end  44  of the post  40 . In this position, an end of tubular insert portion  16  abuts the seal  20  and the nut flange  34 , with a remainder of tubular insert portion  16  sandwiched between the flange end  44  of the post  40  and a portion of nut  30 . The flexible brim  12  extends past the flange end  44 , but is not flush with the flange end  44  so that it can adapt to the shape of both the cable port and the connector  100  with the coaxial cable housed within it. In this embodiment, the post  40  does not require a lip  42 , as was shown in  FIG. 3  with the seal  10 . Once the connector  100  engages the cable port and is advanced to have an inner conductor of the cable enter the port, the seal  20  can be deformed to a position necessary to fill gaps or tightly connect, physically and electrically, the connector  100  to the port. 
     Referring to  FIG. 5 , a port terminator  101  is shown. As is known in the art, a port terminator is fastened into an unused port of a device to provide an environmental seal to protect the inside components of the device and to provide an electrical “appearance” to the circuitry of the device that is neutral. That is to say, if the device expects to see a cable connector with 75 ohms of impedance at a given port, the port terminator provides the 75 ohms of impedance the device is looking for. 
     Referring also to  FIG. 11 , an equipment port  2  is shown, which includes a connector end  4 , a conductor port  6 , and at least one thread  8 . 
     Port terminator  101  includes an outer nut  201  which has a plurality of grooves  221  and ridges  241  to enhance contact between an installer&#39;s fingers (not shown) and port terminator  101  during installation and removal. At least one thread  261  on an inside of one end of outer nut  201  permits port terminator  101  to be screwed onto port  2  of a device (not shown). A termination resistor  321 , which can be in the form of a peanut resistor, is positioned inside an insert chamber  403  and a nut chamber  281  of outer nut  201  as will be explained later. 
     Referring also to  FIGS. 6-7 , termination resistor  321  includes an insulator  341  surrounding an electrical resistance, a conductor portion  361 , and a ground portion  381 . Conductor portion  361  is designed to enter equipment port  2  and connect with the device (not shown) in the same manner as a center conductor of a coaxial cable (not shown). The electrical path runs from conductor port  6  to conductor portion  361 , through termination resistor  321  to ground portion  381 , to a ground insert  401 , and then to connector end  4 . Outer nut  201  is preferably made of injection molded plastic, and is preferably non-electrically conductive, but can optionally be made of an electrically conductive material in which case the use of ground insert  401  permits good port termination even if the outer nut is not screwed tightly onto equipment port  2 . 
     Nut chamber  281  is cylindrical and contains at least one thread  261  therein, with a diameter sized to screw onto equipment port  2 . Insert chamber  403  is also cylindrical, but is of a smaller diameter than nut chamber  281 . Ground insert  401  is preferably press-fit into insert chamber  403  within outer nut  201 . Ground insert  401  is of an electrically conductive material, preferably metal, although other electrically conductive materials are known in the art. Ground insert  401  includes a capture portion  481  for capturing (receiving) and making good electrical contact with ground portion  381  of termination resistor  321 . An angled portion  425 , frustoconical in shape, connects capture portion  481  with a middle portion  461  of ground insert  401 . Middle portion  461  is preferably sized so that its outer surface makes contact with the walls of insert chamber  403 , while its inner surface helps to hold termination resistor  321  in place. 
     Termination resistor  321  is preferably connected to capture portion  481  of ground insert  401  in one of several ways to improve both the electrical connection and the physical connection. For example, termination resistor  321  could be crimped into capture portion  481 , or it could be soldered. One method of connection would be to insert termination resistor  321  into capture portion  481  and then crimp capture portion  481  onto termination resistor  321 . Another method of connection would be to partially crimp capture portion  481  and then insert termination resistor  321  into capture portion  481 . 
     Middle portion  461  of ground insert  401  connects to a plurality of flat petals  441  and biased petals  421  via a transition band  423 . Flat petals  441  are preferably alternated with biased petals  421 . When port terminator  101  is screwed onto equipment port  2 , petals  441 ,  421  are preferably forced onto connector end  4 , and possibly onto thread  261  and/or a flat portion  283  of outer nut  201  which separates insert chamber  403  from nut chamber  281 . The partial deformation of petals  421 ,  441  ensures excellent electrical contact between ground insert  401  and connector end  4  of equipment port  2  and provides enhanced RF shielding. 
     Referring to  FIGS. 8-10 , a ground insert  501  is shown which is similar to ground insert  401  except that instead of petals, a flexible brim  507  is used. Ground insert  501  fits into insert chamber  403  within outer nut  201 . Ground insert  501  is of an electrically conductive material, preferably metal, although other electrically materials are known in the art. Ground insert  501  includes a capture portion  505  for capturing (receiving) and making good electrical contact with ground portion  381  of termination resistor  321 . An angled portion  511 , frustoconical in shape, connects capture portion  505  with a middle portion  503  of ground insert  501 . Middle portion  503  is preferably sized so that its outer surface makes electrical contact with the walls of insert chamber  403 , while its inner surface helps to hold termination resistor  321  in place. 
     As with the previous embodiment, termination resistor  321  is preferably connected to capture portion  505  of ground insert  501  in one of several ways to improve both the electrical connection and the physical connection. For example, termination resistor  321  could be crimped into capture portion  505 , or it could be soldered. One method of connection would be to insert termination resistor  321  into capture portion  505  and then crimp capture portion  505  onto termination resistor  321 . Another method of connection would be to partially crimp capture portion  505  and then insert termination resistor  321  into capture portion  505 . 
     Middle portion  503  of ground insert  501  connects to flexible brim  507  via a transition band  509 . When port terminator  101  is screwed into equipment port  2 , flexible brim  507  is preferably forced against connector end  4 , and possibly onto flat portion  283  of outer nut  201  which separates insert chamber  403  from nut chamber  281 . The partial deformation of flexible brim  507  ensures excellent electrical contact via rim  513  between ground insert  501  and connector end  4  and provides enhanced RF shielding. 
     Both ground insert  401  and ground insert  501  are preferably formed using a progressive die process, with stamping in successive stages. 
     While the present invention has been described with reference to a particular preferred embodiment and the accompanying drawings, it will be understood by those skilled in the art that the invention is not limited to the preferred embodiment and that various modifications and the like could be made thereto without departing from the scope of the invention as defined in the following claims.