Abstract:
A remotely-controlled manipulator for mounting to the end of a telescopic boom, includes at least one releasable support mounted to a cross member for releasably holding or clamping an elongate object.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priority from U.S. Provisional Patent Application No. 60/357,116 filed Feb. 19, 2002 entitled Apparatus for Precisely Manipulating Elongate Objects Adjacent to Energized Overhead High Voltage Transmission Lines. 

   BACKGROUND OF INVENTION 
   This invention relates to a device which is attached to the boom of a crane, for the precise and remote manipulation of an object such as a cross-arm or insulator, adjacent to energized overhead high voltage transmission lines, or the lines themselves. 
   The replacement and installation of cross arm members or insulators on overhead transmission towers is generally accomplished, whenever possible, while the electrical transmission lines are energized. It is common to find several rows of transmission towers supporting two or more vertically separate electrical transmission lines located in relatively close proximity. This confined overhead working area emphasizes the need for the precise elevating and manipulation of objects so as to avoid accidental arcing between the energized lines and the object with obvious dire consequences to workmen and machinery. A convenient practise is to employ a helicopter to elevate such objects to workmen on the tower. However, where a tower supports vertically separated energized lines, wind gusts and rotor downwash make this practice difficult and may require the de-energising of a portion of the electrical transmission line. Such de-energizing is undertaken only as a last resort. The present invention provides a relatively easily controllable apparatus, which is able to elevate and accurately position power transmission lines or elongate, electrically conductive structural members such as supporting arms for power lines and insulators within the generally confined overhead work space associated between vertically separated electrical transmission lines or between horizontally spaced transmission towers. Further, the present invention permits elongated electrically conductive structural members, such as supporting cross arms for power lines and insulators, to be elevated generally parallel to and above one or more energized power lines with minimum displacement therefrom, thereby avoiding accidental contact between the lines and the electrically conductive structural members. Once elevated to the required position, for example, a replacement cross arm may be arcuately rotated in a horizontal plane into a preselected position adjacent to the electrical transmission line-supporting tower and generally at right angles to the power lines. 
   SUMMARY OF INVENTION 
   The present invention may be characterized as an arm, hingedly connectable to the distal end of a hydraulically actuated crane boom and arcuately adjustable by means of an actuator such as a hydraulic ram in a direction generally parallel to the boom so as to effectively change the angular disposition and orientation between the crane boom and the hinged arm. By that adjustment, the arm may be positioned generally horizontally regardless of the boom angle. 
   In normal operation, the crane boom is extended and raised to elevate the arm while holding an elongate object such a power line supporting cross arm in a controlled manner, adjacent to one or more energized power lines. The hingedly connected arm is then manipulated to bring the cross arm being held into general parallel alignment with, but spaced vertically above or below, the energized power line. The boom is then swung in a horizontal plane to position the cross arm adjacent to the electrical transmission line-supporting tower, generally at right angles to the power lines without the danger of accidental contact with the energized power lines. 
   The present invention is, thus, in one aspect a device for the precise and remote manipulation of elongate objects adjacent to energized overhead high voltage transmission lines. The device includes in one preferred embodiment, a first and a second arm, where the first arm is rigidly mounted or otherwise fixedly positioned at the distal end of a crane boom and the second arm is hingedly connected to the first arm in proximity to the point of connection between the first arm and the crane boom. Second arm is arcuately adjustable, relative to both the first arm and the crane boom by means of a selectively, actuable actuator such as a hydraulic cylinder mounted so as to be positioned between the first and second arm. The second arm is arcuately adjustable in a direction generally parallel to the boom so as to effectively change the angular disposition between the crane boom and the second arm. By adjusting the angle between first and second arms, the second arm may be positioned in a generally horizontal attitude regardless of the angle of the crane boom and the connected first arm. 
   The second arm may have receptacles mounted to or otherwise positioned on the underside thereof. The receptacles releasably secure elongated electrically conductive structural members, such as supporting cross arms for power lines to the second arm. Arresting means are mounted or positioned on the underside of second arm to inhibit or prohibit longitudinal sliding translation of the cross arm relative to the second arm when the cross arm is mounted within the securing receptacles. 
   In summary then, for mounting to the end of a telescopic boom, the present invention may be summarized as a remotely-controlled manipulator for manipulating an elongate cross-arm. The manipulator may include at least one, or at least one pair of grapples, yokes, collars, clamps or the like (hereinafter releasable supports) mounted spaced apart along a rigid elongate member (hereinafter a cross member) for releasably grasping, holding or clamping one end of the cross arm so as to cantilever the cross arm from the cross member, away from the boom. 
   The cross member is mounted to the upper or free end of the boom, for example by means of a mounting member rigidly mounted to the upper or free end of the boom. The mounting member may be a boom extension member. The cross member supporting the releasable supports is pivotally mounted for pivotal or rotational movement in a vertical plane and, by rotation on the boom, in a horizontal planes. The cross-member pivots relative to the boom by pivotal actuating means. In one embodiment the cross member is pivotally mounted to the boom extension member for pivoting in the vertical planes. The cross member may be pivoted in the horizontal plane by, for example approximately fifteen degrees by rotation of the boom in order to allow alignment of the cross arm to the poles of the transmission structure. Without this horizontal plane movement, it may be virtually impossible to line up the cross arm totally parallel to the transmission poles. 
   A selectively and remotely actuable actuator such as a hydraulic cylinder or ram is mounted between the boom or boom extension member and the cross member for rotating or pivoting the cross member relative the boom or boom extension member. A cross arm in, and cantilevered by its first end from, the releasable supports is thereby selectively pivoted or rotated about its first end so as to be adjustable into a horizontal orientation. 
   In a preferred embodiment, the releasable support mounted on the cross member is at least one collar mounted to an underside of the cross member. The invention may also include at least one insulated extension member mounted at one end to the cross member and adapted at its opposite end for mounting to a single phase of a power transmission line. 
   The present invention allows for the cost effective transfer of the line, that is the existing phase, from the existing cross arm onto the new cross arm. Using insulated phase holders or extension members mounted on the cross member of the present invention, the existing phase is removed from the existing cross arm, and lowered to hang free. The existing cross arm is then cut-out and replaced with a new cross arm again using the present invention, this time without using the insulated members on the cross member for holding the single phase. The phase holders are then remounted to the cross member and the phase lifted for attachment to the new cross arm on the tower. In this fashion a single machine may be used to accomplish both the removing and replacement of the cross arm and the transmission line. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a side elevation view of the apparatus secured to the distal end of a crane boom and pivoted to a horizontal position. 
       FIG. 1   a , is a schematic elevation view of a high voltage electrical transmission tower with a replacement cross arm being elevated into position by a mobile crane using the present invention. 
       FIG. 2  is a side elevation view of the apparatus secured to the distal end of a crane boom prior to adjusting the angle of the second arm. 
       FIG. 3  is an isometric view of the present invention. 
       FIG. 4  is a sectional view along line  4 — 4  in FIG.  1 . 
       FIG. 5  is a sectional view along line  5 — 5  in FIG.  1 . 
       FIG. 6  is a sectional view along line  6 — 6  in FIG.  1 . 
       FIG. 7  is a sectional view along line  7 — 7  in FIG.  1 . 
       FIG. 8  is a sectional view along line  8 — 8  in FIG.  1 . 
       FIG. 9  is a sectional view along line  9 — 9  in FIG.  1 . 
       FIG. 10  is an exploded isometric view of the components of one embodiment of the first arm of the present invention. 
       FIG. 11  is an exploded isometric view of the components of one embodiment of the second arm of the present invention. 
       FIGS. 12   a - 12   g  are side elevation views of the apparatus of  FIG. 1 , adapted for holding and manipulating power transmission lines by the use of insulated extensions. 
   

   DETAILED DESCRIPTION 
   With reference to the drawing figures, wherein similar characters of reference denote corresponding parts in each view,  FIG. 1   a  schematically illustrates a high voltage electrical transmission tower  10  having mounted thereon several cross arms  12 . A replacement cross arm  12   a  (shown in dotted outline) is supported and positioned by a manipulating apparatus  14  according to the present invention, which is mounted to the distal end  16   a  of a telescopic boom  16  of mobile crane  18 . 
   As better seen in  FIGS. 1-3 , manipulating apparatus  14  has first arm  20  fixedly mounted or secured, for example by bolting or welding, at end  20   a , to distal end  16   a  of crane boom  16 . A second arm  24  is hingedly or pivotally mounted or connected to first arm  20 . Brackets  26  are welded to first arm  20  in proximity to end  20   a . Corresponding brackets  30  are welded at end  24   a  of second arm  24 . Brackets  30  are pivotally mounted to brackets  26 . Selectively actuable hydraulic cylinder  34  is mounted so as to extend between distal or free end  20   b  of first arm  20  and attachment bracket  38  mounted to second arm  24 . By actuation of cylinder  34 , second arm  24  may be incrementally pivoted relative to first arm  20 , for example, pivoted between a raised position generally or close to parallel to first arm  20  and a lowered position for example a position generally at, or close to being at right angles to first arm  20 . 
   A pair of cross arm retaining yokes or collars  42 , as better seen in  FIGS. 4 and 5 , are secured as by welding, spaced apart along second arm  24 . Collars  42  secure a replacement cross arm  12   a  so as to be releasably mounted snugly underneath second arm  24 . Each collar  42  has a hinged arm or base  42   a . Base  42  is pinned or bolted to the free ends of collars  42 . Thus one bolt or shackle  43   a  may serve as a hinge or pivot, and the opposite bolt or shackle  43   b  may be inserted or removed to respectively lock or release base  42   a  to or from the free ends of collars  42 . As better seen in  FIG. 6 , arresting plate  48  is mounted to second arm  24 , for example near end  24   a , to form a stop against which one end of cross arm  12   a  abuts when mounted in collars  42 . 
   As seen in  FIGS. 7-11 , similar to second arm  24 , first arm  20  may advantageously be an I-beam. End  20   a  may be journalled into an end support  50  so as to form a rigid extension from boom end  16   a . Support  50  may be bolted or welded both to end  16   a  and to end  20   a , for example so as to sandwich one end of brackets  26  against the outer edges of the flanges of the I-beam. As seen in  FIG. 9 , bracket  34   a  is rigidly mounted to end  20   b  so as to pivotally support the upper end of cylinder  34 , the opposite end pivotally mounted to bracket  38 . 
   As replacement cross arm  12   a  is elevated adjacent high voltage electrical transmission tower  10 , it is positioned so as to extend outwardly from and generally parallel to boom  16  of mobile crane  18  in a manner which will avoid accidental contact with the high voltage power lines. Once elevated to the desired position, remote hydraulic actuation of cylinder  34 , normally by the operator of mobile crane  18 , rotates second arm  24  of manipulating apparatus  14  and the secured replacement cross arm  12 , outwardly of boom  16  toward a generally horizontal alignment. In this alignment the crane boom can be manoeuvred to rotate apparatus  14  and replacement cross arm  12  in a generally horizontal plane toward transmission tower  10  free from accidental contact with the energized lines. 
   As seen in  FIGS. 12   a - 12   g , insulated rigid elongate extension members  52  may be mounted to cross member  24  at their base ends  52   a . A power transmission line grapple or clamp or other releasable holding means or support  54  for releasably grasping a power line is mounted to the opposite distal end  52   b  of exte 3 nsion members  52 . A plurality of members  52  may be mounted to cross member  24 . They may be oriented in various radial orientations about cross member  24 , for example, extending up from, depending down from, or linear to cross member  24 , lying in a plane containing members  20  and  24 . 
   As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modificaare possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.