Jib adapter for an electrically insulated high voltage wire holder
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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.

Krejci, William (Mentor, OH, US)
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Primary Examiner:
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I claim:

1. An electrically insulating jib assembly for lifting high-tension wires comprising: a rectangular lifting jib holder of non insulating material having a rectangular inner core; a rectangular adapter insert of insulating material having a central opening therein; and an electrically insulated jib conforming to said central opening to allow it to move inside said adapter.

2. An electrically insulating jib assembly as set forth in claim 1 wherein said central opening is circular and said insulated jib is also circular to slide within said central opening.

3. An electrically insulating jib assembly as set forth in claim 2 wherein said adaptor and said jib is made from nylon material.

4. An electrically insulating jib assembly as set forth in claim 3 including end caps on each end of said adaptor larger than the jib holder opening for retaining said adaptor inside said jib holder.

5. An electrically insulating jib assembly as set forth in claim 4 wherein said end caps have a central opening for allowing said jib to pass terethrough.

6. An electrically insulating jib assembly as set forth in claim 5 wherein said adaptor has a series of holes therein for allowing a pin to extend into the central opening thereof.

7. An electrically insulating jib assembly as set forth in claim 6 wherein said jib has a series of holes alignable with one of said holes in said adaptor for retaining said jib in said adaptor.



1. Field of the Invention

The present invention is generally drawn to high tension electrical wire supports and more particularly to electrically insulted jib assemblies.

2. Description of the Prior Art

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.

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.

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.

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.

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.

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.

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.

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.


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.

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.

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.

Another aspect is to provide a jib assembly suitable for directly handling high-tension electrical wires.

Yet another aspect is to provide an adapter for mounting a circular solid insulator jib to an existing rectangular jib mount.

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.


In the drawings wherein:

FIG. 1 is a prior art schematic of existing truck boom and jib assemblies;

FIG. 2 is a depiction of how existing jib assemblies are used to handle high-tension electrical wires;

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;

FIG. 4 is a showing of the jib assembly of the present invention having adaptors for hydraulic jib movement;

FIG. 5 shows the existing rectangular lifting jib being removed from the boom end housing;

FIG. 6 shows the insulating jib adaptor mounted in the FIG. 5 housing;

FIG. 7 shows the solid circular jib adaptors for manual and for hydraulic movement from the boom;

FIG. 8 shows the solid circular jib adapted for hydraulic movement from the boom; and

FIG. 9 shows the jib of the present invention used to retain and lift a high-tension wire.


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.

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.

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.

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.

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.

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


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