Abstract:
A plastic shield for a cable and insulator is described having a center section for covering the insulator. The center section has an opening at both its ends for the cable. Proximate each opening is a pivotable and bendable flange, where the flange pivots at one end of the flange and freely bends. An arm extends from each of the cable openings of the center section, and each arm covers the cable exiting the center section. Each arm is pivotally attached to the other end of the associated flange. The flange allows its associated arm to be moved over a wide range of horizontal and vertical angles (e.g., up to 45 degrees) and allows the arms to have a variable horizontal and vertical offset relative to the center line of the center section and insulator to accommodate a cable that is offset from the center line.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation-in-part of U.S. patent application Ser. No. 13/466,778, filed on May 8, 2012, by Michael Lynch, incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a shield for a high voltage cable and its supporting insulator to prevent shorting by wildlife and trees, and, in particular, to a shield that adapts to any angle and asymmetry of the cable bending around the insulator. 
       BACKGROUND 
       [0003]    It is common to support medium to high voltage (e.g., greater than 2 Kvolts) cables on wooden poles supported by ceramic insulators. Frequently, there are three parallel cables, each carrying a different phase. If there is a short to ground or a short between cables, a fuse or breaker will trip, causing a power outage or a rerouting of the electricity. A lineman must then fix the problem and reset the fuse/breaker. 
         [0004]      FIG. 1  is a perspective view of a conventional ceramic insulator  10  that is mounted on a wooden pole (not shown) using conventional hardware, such as a bracket or a bolt. Round insulators are typically 4-8 inches in diameter. A bare cable  12  is secured to the insulator  10  by a wire (not shown) twisted around the insulator neck  13  and the cable  12 .  FIG. 2  is a top down view of the insulator  10  and cable  12 . For three phase distribution, there are typically two insulators/cables at the ends of a wooden cross-arm and one insulator/cable supported in the middle or on the top of the pole. 
         [0005]    When there is a straight run of the cable  12 , the cable  12  may be supported by the indent  14  at the top of the insulator  10  or may be tied to the side of the neck  13 . A twist wire keeps the cable  12  in place. When the cable path needs to change direction, the cable  12  is bent around the neck  13  of the insulator  10 , as shown in  FIGS. 1 and 2 . If the cable  12  is supported by the indent  14 , for a straight run, the structure is symmetrical. If the cable  12  is tied to the side of the neck  13 , as shown in  FIGS. 1 and 2 , the structure is asymmetrical. 
         [0006]    In locations where there are trees, large birds, other animals, or the voltage is particularly high, cable shields are sometimes used to prevent arcing by a tree or an animal when the tree or animal contacts two or more of the phased cables. It is common to only put the shield over the center insulator/cable. Such shields are formed of a plastic, which may be resilient or rigid. 
         [0007]    Shields that simply cover a straight cable  12  supported by the top indent  14  of the insulator  10  are simple and adequate, since the insulator/cable structure is symmetrical. 
         [0008]    Shields are known that have two arms extending from a wide central portion of the shield that covers the ceramic insulator, where the arms cover the cable extending in both directions. The shield is formed of a soft, resilient plastic, and the arms can bend at different angles relative to the central portion. One such shield is the Tyco Electronics Corporation BCIC-G-PIN-795 raptor guard, whose arms flex up to 30 degrees. 
         [0009]    One problem with the BCIC-G-PIN-795 shield is that it assumes the cable  12  is supported symmetrically at the center of the insulator  10  within the indent  14 . However, if the cable  12  is bent around the neck  13  of the insulator  10 , the insulator/cable is not symmetrical, and the shield will not properly fit over the insulator  10  and cable  12 . As a result, the resilient shield material will be angled and distorted. This reduces the effectiveness of the shield and is not aesthetically pleasing. An angled shield opens up the underside of the shield to the wind, placing a large strain on the shield. 
         [0010]    What is needed is a universal shield for cables supported by insulators, where the shield precisely adapts, without any distortion, to the asymmetrical arrangement of a cable  12  bent around the neck  13  of the insulator  10 , as well as when the cable  12  is supported by the indent  14  at the top of the insulator  10 . 
       SUMMARY 
       [0011]    A plastic shield for a cable and insulator is described comprising a center section for covering the insulator. Two arms extend from the center section and each is attached to the center section by a respective pivoting flange. The flange has a first pivoting connection point at one end and a second pivoting connection point at its other end. The first pivoting connection point is attached to the center section, and the second pivoting connection point is attached to one of the arms. The length of the flange will typically be about 2-3 inches. The flange allows its associated arm to be moved over a wide range of lateral angles (e.g., up to 45 degrees) to accommodate a bend in the cable. To accommodate a cable that is laterally offset from the center of the insulator when the cable is tied to the side of the insulator&#39;s neck, the flange, by pivoting around the arm, adds a lateral offset up to 3 inches for each arm. The length of the flange is set to accommodate the offset between the center of the insulator to the center of the cable when the cable is tied to the side of the neck of the insulator. The flange may have any suitable length (e.g., 2-4 inches), depending on the maximum size of the insulator. 
         [0012]    In another embodiment, the flange is additionally bendable in the Z-axis direction. Accordingly, not only can the cable be offset in the horizontal (lateral) direction with respect to the center line of the insulator (by the above-described pivoting feature), but the cable can be at variable distances above or below the center line of the insulator while not imposing any stresses on the structure. Therefore, the arms and center section of the shield are optimally connected over the cables and insulator irrespective of any vertical or horizontal offset of the cable with respect to the insulator. Since such offsets are frequently unpredictable until the lineman secures the cable to the insulator, the flexibility of the present invention satisfies an important need in the field. The flange may be bendable by being formed of an easily flexible material, or the flange may have one or two hinges along its length that allow it to accommodate the vertical offset. The flange is thus pivotable and bendable. 
         [0013]    Another unique aspect of the shield is that each arm comprises a short arm adaptor, that connects to the flange located within the center section of the shield, and an arm extension that fits over the portion of the arm adaptor that extends beyond the center section. Any length arm extension may be fitted over the arm adaptor. The small size of the arm adaptor makes it is easy to manipulate when connecting it, via the flange, to the center section. Also, the arm adaptor may be formed of a more rigid material than the arm extension, and the arm extension can be selected to have different lengths. 
         [0014]    The arm adaptor has a flared end (toward the ceramic insulator) to prevent water dripping on the cable. The arm adaptor has vertical ribs, and the arm extension has vertical grooves that receive the ribs as the arm extension is brought down into position over the arm adaptor. The molded grooves form protruding ribs on the outside of the arm extension that divert water to prevent the water entering the center section. 
         [0015]    Holes are provided along the shield for receiving plastic pins that are inserted using a hot stick. The pins prevent the shield being lifted off the cable and insulator. Each hole may optionally have a cowl over it to prevent the pins being used as a bird perch. 
         [0016]    Other features of the shield are also described. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of a prior art insulator and cable. 
           [0018]    Fig. is a top down view of  FIG. 1 . 
           [0019]      FIG. 3  is an exploded perspective view of the arm adaptor and flange. 
           [0020]      FIG. 4  is a perspective view of the arm extension being connected to the arm adaptor. 
           [0021]      FIG. 5  is a semi-transparent side view of the completed shield in a straight configuration, with the arm adaptor being connected to the center section solely by the pivoting flange. 
           [0022]      FIG. 6  illustrates the shield of  FIG. 5  positioned over an insulator and a cable. 
           [0023]      FIGS. 7-12  are semi-transparent top down views of the shield, where the cable is at different angles and different offsets from the center line. 
           [0024]      FIG. 7  illustrates the shield, where the cable is slightly bent around the neck (upper part of neck in  FIG. 7 ) of the insulator, causing both arms to be offset (upward in  FIG. 7 ) to accommodate the asymmetry of the insulator/cable. 
           [0025]      FIG. 8  is a wider view of the shield of  FIG. 7  showing the arm extensions. 
           [0026]      FIG. 9  illustrates the shield, where the cable runs straight from the right and is bent around the neck (bottom part of neck in  FIG. 9 ) of the insulator, causing one arm to be straight and offset and the other arm to be angled and not offset. 
           [0027]      FIG. 10  illustrates the shield, where the cable is supported by the indent in the top of the insulator and running straight, causing the shield&#39;s arms to be straight and not offset. 
           [0028]      FIG. 11  illustrates the shield, where the cable is bent around the neck (the bottom part of the neck in  FIG. 11 ) of the insulator, causing both arms to be angled and not offset due to the particular angle. 
           [0029]      FIG. 12  illustrates the shield, where the cable runs straight from the left side and is bent around the neck (the bottom part of the neck in  FIG. 12 ) of the insulator, causing one arm to be straight and offset and the other arm to be angled and offset. 
           [0030]      FIG. 13A  is a front view of a pin that may be used to secure the shield over the insulator and cable. 
           [0031]      FIG. 13B  is a side view of the pin of  FIG. 13A . 
           [0032]      FIG. 14  is a perspective view of a flange that can pivot in the lateral direction and also bend in the vertical direction. The flange has a keyhole and a key for fast snap-in installation. 
           [0033]      FIG. 15  is a perspective view of a variation of the flange of  FIG. 14  where the pivoting connection to the center section or arm adaptor uses a bolt, while the pivoting connection to the other portion of the shield uses a snap-in keyhole connector for easy assembly in the field. 
           [0034]      FIG. 16  is a side view of a bendable flange made of an easily bendable material. 
           [0035]      FIG. 17  is similar to  FIG. 6  but the flange of  FIGS. 3 and 4  is replaced by one of the bendable flanges of  FIGS. 14-16  to allow variability in the Z-direction between the arm adaptor and the center section. 
       
    
    
       [0036]    Elements labeled with the same numerals may be identical or similar. 
       DETAILED DESCRIPTION 
       [0037]    The invention is a shield or cover for an insulator supporting a cable carrying medium or high voltages, where the insulator is supported by a utility pole or tower. The shield will typically be a molded plastic material such as a slightly resilient PVC or HDPE. The shield prevents arcing caused by large birds, animals, or trees bridging the gap between cables carrying different phases or between a cable and ground. The cables may be run laterally spaced from each other run vertically spaced from each other. 
         [0038]      FIGS. 3-5  illustrate the four connectable pieces of the shield. 
         [0039]      FIG. 3  illustrates and arm adaptor  16  and a flange  18 . The arm adaptor  16  is formed to have a U-shape to cover the cable. The top portion of the arm adaptor  16  has a keyhole  20  comprising a wide hole  22 , a small hole  24 , and a constrictor  26  that is slightly narrower than the hole  24 . In one embodiment, the wide hole  22  is about 0.5 to 0.75 inches in diameter, and the small hole  24  is slightly less than half the diameter of the wide hole  22 . 
         [0040]    The flange  18  includes a bottom, cylindrical connector  28  having a flat bottom extension  30 . The connector  28  and extension  30  fit through the wide hole  22  in the arm adaptor  16 , and the flange  18  is then forced backward (as shown by arrow  31 ) to cause the connector  28  (or constrictor  26 ) to slightly deform when passing through the constrictor  26 . When the connector  28  is positioned within the small hole  24 , the connector  28  is effectively locked into the hole  24  and can pivot freely. The extension  30  prevents the flange  18  from being released vertically through the small hole  24 . The arm adaptor  16  material and flange  18  material are selected to have a suitable resiliency to allow the locking to occur. The flange&#39;s  18  movement will be substantially restricted to only pivoting (rather than tilting) due to the extension  30  and flange  18  bottom surface abutting the bottom and top surfaces, respectively, of the shelf surrounding the small hole  24 . 
         [0041]    The flange  18  has an identical keyhole  34 , having a wide hole  36 , constrictor  37 , and small hole  38  for attachment to a connector and extension within a center section of the shield (described later) that are identical to the connector  28  and extension  30  described above. 
         [0042]    The arm adaptor  16  has protruding vertical ribs  40  and  41  for being inserted in corresponding grooves in an arm extension. A hole  42  is formed in the arm adaptor  16  for receiving a pin. The hole  42  is elongated to allow some misalignment between the arm adaptor  16  and the arm extension. 
         [0043]    The arm adaptor  16  has a flared end  46  (toward the ceramic insulator) to prevent water dripping on the cable. 
         [0044]      FIG. 4  illustrates the arm extension  48  being aligned with the arm adaptor  16  for fitting them together. The molded ribs  50  and  52  on the arm extension  48  form grooves inside the arm extension  48  for receiving the ribs  40  and  41  on the arm adaptor  16 . The heights of the arm extension  48  and arm adaptor  16  may be on the order of 3-6 inches, and their widths may be on the order of 1-2 inches to accommodate a cable. 
         [0045]    The ribs  50  and  52  additionally block water travelling along the arm extension  48  toward the cable or insulator. 
         [0046]    The arm extension  48  includes holes  54  for receiving a pin that extends below the cable for preventing the shield coming off the cable. One hole  54  is shown having a cowl  56  over it to prevent birds from using the pin as a perch. The hole  54  between the ribs  50  and  52  may optionally have a cowl. 
         [0047]      FIG. 5  shows the center section  60  that has a center cavity which receives the neck  13  ( FIG. 1 ) of the insulator  10 .  FIG. 6  illustrates the shield covering the insulator  10  and cable  12 . The insulator  10  is connected to a utility pole or tower. The arm adaptors  16  and  61  are identical, and the arm extensions  48  and  62  are identical. 
         [0048]    Near the openings of the center section  60  are down-extending cylindrical connectors  63  and  64 , each with a flat bottom extension (obscured in  FIG. 5 ), that are identical to the connector  28  ( FIG. 3 ) and extension  30  of the flange  18 . All features of each part (e.g.,  16 ,  18 ,  60 ,  48 ) are molded so that each part is a single piece. The flange top keyhole  34  ( FIG. 3 ) is snapped into the connector  63  so that the connector  63  pivots in the small hole  38  in the flange  18 . This allows the arm adaptor  16  to pivot around the flange connector  28  and move laterally (for offset) with respect to the center section  60 . Holes  65  in the center section  60  receive pins that extend under the cable  12  for securing the center section  60  over the insulator  10 . 
         [0049]      FIG. 7  is a top down view of the shield covering the insulator  10  and cable  12 . The center section  60  has a center line (not shown) bisecting it along its length. The cable  12  is wire-tied to the side of the insulator  10  neck which, in  FIG. 7 , is the upper side of the neck. The cable  12  is slightly bent. Since the cable  12  is not symmetrical with the insulator  10 , the arm adaptors  16  and  61  are offset (pivoted with respect to flanges  18  and  68 ) to accommodate the asymmetry and are angled to accommodate the slight bend in the cable  12 . Note how the flanges  18  and  68  are not in-line with either the center section  60  or the arm adaptors  16  and  61 . If the opening to the arm adaptor  16  or  61  does not align with the center line bisecting the center section  60  (due to the flange pivoting with respect to the arm adaptor), the arm adaptor is considered to be offset. In other words, the flanges  18  and  68  allow the arm adaptors to have a lateral offset relative to the center line of the center section  60  and insulator  10  to accommodate a cable  12  that is offset from the center line. 
         [0050]    The center section  60  has flared openings  69  to allow side to side movement of the arm adaptors  16  and  61 . Cowls  70  are shown over the pin holes  65 . 
         [0051]      FIG. 8  is a widened view of  FIG. 7  to show the arm extensions  48  and  62 . 
         [0052]    In  FIGS. 9-12 , the insulator  10  and cable  12  are not shown for simplicity. 
         [0053]      FIG. 9  illustrates the shield, where the cable runs straight from the right and is bent around the neck of the insulator, which is the bottom of the neck in the top view of  FIG. 9 , causing the arm extension  62  to be straight and offset (by the arm adaptor  61  pivoting around the flange  68 ), and the arm extension  48  to be angled but not offset (no pivoting of the arm adaptor  16  around the flange  18 ). 
         [0054]      FIG. 10  illustrates the shield, where the cable is supported by the indent  14  ( FIG. 1 ) in the top of the insulator  10  and runs straight (creating a symmetrical structure), causing the shield&#39;s arm extensions  48  and  62  to be straight and not offset (no pivoting around the flanges). 
         [0055]      FIG. 11  illustrates the shield, where the cable is bent around the neck of the insulator, which is the bottom part of the neck in the top view of  FIG. 11 , causing both arm extensions  48  and  62  to be angled. Due to the large bend, the arm adaptors  16  and  61  are not offset (i.e., the cable approximately passes directly under the cylindrical connectors  63  and  64  on the center support  60 ). 
         [0056]      FIG. 12  illustrates the shield, where the cable runs straight from the left side and is bent around the neck of the insulator, which is the bottom part of the neck in the top view of  FIG. 12 , causing the arm extension  48  to be straight and offset and the arm extension  62  to be angled and offset. 
         [0057]      FIG. 13A  is a front view of a plastic retaining pin  90  that may be used to secure the shield over the insulator  10  and cable  12 .  FIG. 13B  is a side view of the pin  90  of  FIG. 13A . The pin  90  may be 3-4 inches long, sufficient to pass through both opposing holes along the shield&#39;s length below the cable  12  to prevent the shield from coming off the cable and insulator. 
         [0058]    The end of the pin  90  has a round grasping hole  92  for grasping by a hook of a hot stick. 
         [0059]    The nose  94  has a relatively long front portion  95  that expands out from the tip at about a 15 degree angle. The nose  94  has an opening to allow the nose to be compressed when passing through a hole slightly larger than the shaft of the pin  90 . The shallow angle and long nose allow the pin  90  to be pushed through the holes in the shields using a relatively low pushing force to compress the nose  94 . The back part  96  of the nose is relatively short and has a relatively steep angle of about 45 degrees, so as to require a higher pulling force to compress the nose when removing the pin from the hole. This ensures that the pin  90  will not be inadvertently pulled out of the hole during high winds. In one embodiment, the insertion force is about three pounds, and the removal force is about six pounds. It is much easier to pull on a pin with a long hot stick, so the increased pulling force is not a problem for the lineman. 
         [0060]    Many variations of the flange  18 , arm adaptor  16 , arm extension  48 , and center section  60  may be used while still achieving the offset of the arms with respect to the center section. In another embodiment, the arm adaptor and arm extension are an integral piece. 
         [0061]    In some applications, there may be a variety of vertical offsets of the cable with respect to the insulator. For example, in  FIG. 1 , there may be a variety of insulators used in a distribution system with different heights so that the vertical distance between the cable  12  and the top of the insulator  10  may be different. In prior art systems, to accommodate these variabilities, the lineman would have to deform the shield or affix it to the insulator and cable in ways not intended by the manufacturer, thus reducing its effectiveness. Also, the lineman may connect the cable  12  to the insulator  10  so that the alignment of the cable  12  to the insulator  10  is variable. Therefore, it would be desirable to also allow for the cable  12  to have a variable vertical position with respect to the center line of the insulator while still allowing the shield to be optimally positioned over both the cable and the insulator. In that way, only a single type of adjustable shield could be used with a wide variety of combinations of cables, insulators, and connections. 
         [0062]    To achieve this additional feature, the flange  18  ( FIGS. 3 and 4 ) can be replaced with a flange that is bendable in the Z-axis direction. Accordingly, not only can the cable be offset in the horizontal (lateral) direction with respect to the center line of the insulator (by the above-described pivoting feature), but the cable can be at variable distances along the vertical direction with respect to the center line of the insulator while not affecting the connection of the center section  60  of the shield over the insulator. 
         [0063]      FIG. 14  is a perspective view of a plastic flange  100  that can be used instead of the flange  18  of  FIGS. 3 and 4  in the various shield embodiments. For illustration purposes, the flange  100  is bent at its maximum angle for the maximum Z-axis offset.  FIG. 14  shows the connector  102  and extension  104  at one end, which may be identical to the connector  28  and extension  30  in  FIG. 3  so as to fit in the keyhole in the arm adaptor  16  formed by the openings  22 ,  24 , and  26  in  FIG. 3 . The flange  100  also has the same keyhole connector  106  as the flange  18  in  FIG. 3  for being pivotally secured to the center section  60  ( FIG. 5 ). Since the arm extension  48  ( FIG. 4 ) is connected to the arm adaptor  16 , the vertical offset of the arm extension  48  with respect to the center section  60  is also variable. 
         [0064]    The flange  100  has two hinges  108  and  110  that allow the flange  10  end connectors to be in two different vertical planes to allow the center section  60  and arm adaptor  16  to have a variable offset, depending on the location of the cable with respect to the insulator. The three sections of the flange  100  may be molded separately and then snapped together. The material may be a resilient PVC or other plastic. 
         [0065]    Accordingly, the flange  100  can freely pivot in the lateral direction and bend in the vertical direction. 
         [0066]      FIG. 16  is a perspective view of a bendable flange  114  that is a variation of the flange  100  of  FIG. 14 . In flange  114 , one end of the flange  114  is connected to either the central section  60  or the arm adaptor  16  by a bolt, or other type of axis pin, through the hole  116  that loosely secures the flange  14  to that portion of the shield. Such a bolt may be installed in the factory. The center section  60  or arm adaptor  16  then includes threads or another hole for receiving the bolt or other type of axis pin. The other end of the flange  106  has a snap-in connector, such as the keyhole  106  that allows the arm adaptor  16  to be connected to (or disconnected from) the center section  60  in the field, if required. 
         [0067]    Features other than a hinge may be used to allow the flange to bend to provide a vertical offset. 
         [0068]    To provide the bendability of the flange, the flange may instead be formed of a very flexible (resilient) material, such as shown  FIG. 16 , which is a side view of a suitable flange  118  that is being arbitrarily bent. Suitable flexible plastics and rubber materials are known. 
         [0069]    The flange  114  may be pivotally connected to the arm adaptor  16  and center section  60  using any of the methods described above. In the example, a bolt hole  116  and keyhole  106  are shown by dashed lines. 
         [0070]      FIG. 17  is similar to  FIG. 6  but the flange  18  of  FIGS. 3 and 4  is replaced by one of the bendable flanges of  FIGS. 14 ,  15 , and  16  to allow variability in the Z-direction (arrows  120 ) between the arm adaptor  16  and the center section  60 . In other words, the arm adaptor  16  can be variably offset from the center line of the center section  60  in all directions with substantially no stressed placed on any elements in the structure. In the example of  FIG. 18 , the flange  100  is used and labeled  100 A and  100 B. The length of the flange will typically be about 2-3 inches to allow up to about 2 inches of offset from the center line in all directions. 
         [0071]    In some applications, the insulator is near a terminus of the cable, and the cable only extends in one direction from the insulator. In such a case, only a single arm extension  48  and arm adaptor  16  is needed. 
         [0072]    By using the bendable flange, the arm extensions  48  and center section  60  of the shield are optimally connected over the cables and insulator irrespective of any vertical or horizontal offset of the cable with respect to the insulator. Since such offsets are frequently unpredictable until the lineman secures the cable to the insulator, the flexibility of the present invention satisfies an important need in the field. 
         [0073]    Having described the invention in detail, those skilled in the art will appreciate that, given the present disclosure, modifications may be made to the invention without departing from the spirit of the inventive concept described herein. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments illustrated and described.