Abstract:
The present invention is drawn to a solid core electrically insulating jib assembly comprised of a solid core electrically insulating material such as nylon which is retrofittable to replace the existing heavy duty non-insulating jib for direct lift of high-tension wires.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is generally drawn to high tension electrical wire supports and more particularly to electrically insulted jib assemblies.  
         [0003]     2. Description of the Prior Art  
         [0004]     Jib assemblies are well known and are typically described in U.S. Pat. Nos. 5,337,854; 4,466,506 and 4,838,381 and the reader is referred thereto for a fuller understanding of such as well as how they are mounted to booms of truck vehicles used for such work.  
         [0005]     As best seen in  FIG. 1 a  known jib assembly  10  is mounted at the end of an articulated boom  12 , which is conventionally mounted on truck  14  to allow verticall movement of the boom to a location proximate to the work area.  
         [0006]     The jib assembly  10  is used to assist, in the handling of materials by a person carded in a bucket carrier  16 , which is secured to the end of boom  12  by connection to rotatable shaft  18 . The bucket carrier  16  moves rotationally with shaft  18  when shaft  18  rotates relative to the end of boom  12 .  
         [0007]     The bucket carrier  16  may be pivotally mounted to one end of shaft  18  by a conventional bucket rotation drive system (not shown), so that bucket carrier  16  is freely rotatable about an axis perpendicular to shaft  18 .  
         [0008]     The jib assembly  10  comprises a jib  20  slidably extending through a jib housing  22  made from two quadrant plates  24  and  26  extending respectively from each side of housing  22  and which are rotatably mounted on shaft  18  approximate one side of boom  12 . The rotary movement of the jib with its housing is powered by jib motor through a chain speed reducer.  
         [0009]     The longitudinal movement of jib  20  relative to jib housing  22  is effected manually according to the embodiment illustrated in the figures and can be locked at any position by any of a number of well known conventional means such as, for example, holes and pins in the jib housing. Alternatively, jib extension may be hydraulically powered. If powered, a hydraulic cylinder can be mounted on the winch housing in a conventional manner. Existing jibs are intended for lifting heavy loads up to the bucket operator or lifting loads such as electrical transformers.  
         [0010]     Since the existing jib housings are made from either metal or hollow fiberglass, they do not provide sufficient electrical insulation for handling high-tension high voltage electrical wires whichn ar made from stranded aluminum wires. In fact there is a warning label on such hollow fiberglass jibs warning against their use on such exposed electrical wires. When such use is required, a heavy electrical insulator  24  is placed over the wire  26  prior to lifting it with a metal hook  28  located at the end of a wire  30  extending from a pulley  32  on the end of the jib as is best shown in  FIG. 2 .  
         [0011]     Since the only certifiable electrical insulator material for a jib is a solid core electrical insulator which will prevent high voltage electrical conduction across an air gap as is found in hollow fiberglass jibs, an electrically acceptable jib assembly was needed to replace existing jib assemblies when doing high-tension electrical wire work so the wires could be directly handled by the jib.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention solves the problems associated with prior art jib assemblies and others by providing a solid core electrically insulating jib which is assembly retrofitted to replace the existing heavy duty jibs used mainly for heavy lifting which will be suitable for direct lift of high-tension wires. The insulating jib may be easily replaced with the normal lifting jib when the wiring job is completed.  
         [0013]     The insulating jib is comprised of a solid core electrically insulating material such as nylon. While it could be made in the same rectangular shape as the hollow core jib, a solid circular jib allows for material cost savings and uses rectangular electrically insulating material adaptors for mounting the insulating jib to the existing jib mnounting holders on the boom.  
         [0014]     In view of the foregoing it will be seen that one aspect of the present invention is to provide an electrically approved jib replacement for existing lifting jibs.  
         [0015]     Another aspect is to provide a jib assembly suitable for directly handling high-tension electrical wires.  
         [0016]     Yet another aspect is to provide an adapter for mounting a circular solid insulator jib to an existing rectangular jib mount.  
         [0017]     These and other aspects of the present invention will be more fully understood after a review of the following description of the preferred embodiment when considered with the accompanying figures. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     In the drawings wherein:  
         [0019]      FIG. 1  is a prior art schematic of existing truck boom and jib assemblies;  
         [0020]      FIG. 2  is a depiction of how existing jib assemblies are used to handle high-tension electrical wires;  
         [0021]      FIG. 3  is a side by side showing of an existing prior art jib next to the insulating jib and mounting adaptor of the present invention for manual jib movement;  
         [0022]      FIG. 4  is a showing of the jib assembly of the present invention having adaptors for hydraulic jib movement;  
         [0023]      FIG. 5  shows the existing rectangular lifting jib being removed from the boom end housing;  
         [0024]      FIG. 6  shows the insulating jib adaptor mounted in the  FIG. 5  housing;  
         [0025]      FIG. 7  shows the solid circular jib adaptors for manual and for hydraulic movement from the boom;  
         [0026]      FIG. 8  shows the solid circular jib adapted for hydraulic movement from the boom; and  
         [0027]      FIG. 9  shows the jib of the present invention used to retain and lift a high-tension wire. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]     Referring now to the drawings generally and to  FIG. 3  and  7  more particularly, a solid electrically insulating material jib  34  has a series of circular holes  36  along its length and an end cap  38  used for snapping around the wire  26  to hold it in the cavity  40  of the end cap  38 . Since the jib  34  is circular and the existing lifting jib  20  is rectangular and the holders for retaining the lifting jib to the boom are adapted for its rectangular fit, a rectangular adapter  38  is provided having end caps  40  with four holes  42  therein for mounting the adapter  38  to the existing rectangular jib holder  44  by screws  45 .  
         [0029]     As best seen in  FIGS. 5 and 6 , the existing jib  20  is removed from its holder  44  and the rectangular nylon material adapter  38  is inserted into the holder  44 . To keep the adapter  38  from sliding out, the flanges  40  are screwed into both ends of the adapter  44 . The lip  46  on each flange  40  extends beyond the ends of holder  44  and thus captures the adapter  38  therein. The adapter  38  as well as the end caps  40  have matching circular openings  46  which allow the insulating jib  34  to freely move through the adapter  38  and the end caps  40 . The adapter  38  also has a series of holes  48  on one side thereof to allow a pin (not shown) to slide threthrough and extend through one of the aligned holes  36  in the jib  34  when it is inserted in the adapter  38 . This retains the jib  34  to the housing and the boom and allows manual movement of the jib  34  with respect to the boom just as is done with the existing rectangular jib  20  by manually moving it in the holder  44  to allow pining to different location holes. The adapter  38  is also made in differing sizes since jibs are different sizes with most known jibs being either 4 inch or 4½ inch squares.  
         [0030]     For mounting the jib  34  to be hydraulically actuated to move with respect to the boom, a pair of adapters  48 ,  50  are needed. They are located at two areas of on the jib  34  as best seen in  FIG. 4 . The adapter  50  is affixed to the jib  34  by a pin  52  extending through a hole  54  on one side of the rectangular adapter  50 , which is aligned with one of the holes  36  in the jib  34 . The other adapter  48  is free to move along the length of the jib  34 .  
         [0031]     The actual mounting to the boom is best seen in  FIG. 8 . The mounting of the adapter  48  to the holder  44  is done using the end caps  56  similarly to the mounting of the adapter  38 . Since the movement of the jib  34  will be hydraulically there is no need to have any holes in the adapter  48  to manually retain the jib  34  in the holder  44 . Instead, the adapter  50  is mounted in the hydraulically actuated holder  58  by the pin  52  extending through the holder  58  into the hole  54  of the adapter  50  and into one of the holes  36  of the jib  34  aligned with the hole  54 . As the holder  58  moves laterally back and forth, it carries the jib  24  now attached thereto back and forth with respect to the stationary holder  44  retaining it in the stoped position.  
         [0032]     As best seen in  FIG. 9 , the jib  34  is shown actually used to directly hold and lift the high-tension wire without any need for electrical insulation blankets to be licated thereon. The boom is vertically moved from the truck  14  to a position close to the wires  26 . The wire  26  is then moved into the cavity  40  of the end adapter  38  by pressing it against releasable spring clip  54  and the jib  34  is then vertically lifted either manually or hydraulically depending on the truck installation to move the wire to a position where it can be worked on. There is no need for any electrical insulation on the wire  26  since the jib  34  and its nylon adapters are a perfect electrical insulator shielding the jib from the boom.  
         [0033]     It will be understood that certain obvious modifications and additions have been deleted herein for the sake of conciseness and readability but are fully intended to fall within the scope of the following claims