Abstract:
A conductor lift attachment for a mobile boom or crane vehicle allowing temporarily support of power transmission conductors, e.g., for installation, repair, or maintenance operations. The conductor lift is hingedly attached to a boom tip so that the conductor lift is readily movable between deployed and stowed positions. The conductor lift comprises hinged arms that are selectively movable between opposed, parallel, and intermediate positions.

Description:
PRIORITY CLAIMS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/857,771, filed Jul. 24, 2013, and No. 61/883,993, filed Sep. 28, 2013, which are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention is generally directed devices which attach to mobile cranes, lift trucks, and the like, to facilitate temporary support of electrical power transmission lines. 
       BACKGROUND ART OF THE INVENTION 
       [0003]    Transmission and distribution of electrical power typically relies on sets of high-voltage conductors. In one common arrangement, a set of three conductors, each transmitting one phase of a three-phase alternating-current system, are strung in parallel, spaced apart from each other. The conductors often extend long distances and are supported by periodically-spaced poles or towers (“supports”). The supports keep the conductors above the ground and ensure that the conductors remain spaced adequately apart from each other. 
         [0004]    Each support comprises one or more insulator for each conductor. The insulators, often in the form of an insulator stem, are intended to prevent the transmission of current from one conductor to another conductor or to the ground. 
         [0005]    It is often necessary to perform maintenance on or to replace a support, an insulator, or other equipment. However, the hazards inherent in working around high-voltage transmission lines limits the work that can be done on supports and components while energized conductors are in place. Further, since the conductors associated with each support may be providing power to hundreds of thousands of customers, de-energizing the conductors would be a huge disruption to power customers and is therefore impractical. Therefore, it is useful to provide a mobile conductor lift, capable of supporting an energized or nonenergized, multi-phase conductor set, and holding the conductors away from the support being accessed. 
         [0006]    Other mobile conductor support devices have been proposed, such as conductor lifts which attach to the boom of a boom truck, crane, or similar equipment (“vehicle”). Those devices, however, prevent the vehicle from being used for other purposes with the conductor lift attached. Additionally, the conductor lifts are not easily removed or re-installed. Further, when detatched, the prior art conductor lifts are generally large, unwieldy, and difficult to store. 
         [0007]    What is needed is a conductor lift that can remain attached to a boom while allowing the boom to be used for other purposes. Another need is a conductor lift capable of being folded for convenient storage. 
       SUMMARY 
       [0008]    Problems and limitations in the prior art are overcome by providing a conductor lift attachment for a boom lift with a mounting plate. In one embodiment the conductor lift comprising a lift attachment plate configured to hingedly connect to the mounting plate, wherein the lift attachment plate is configured so that the conductor lift is selectively movable from a use-ready position to a stowed position; a lift adaptor attached to the lifter plate; an arm hub attached to the lift adaptor; a first arm hingedly connected to the arm hub; a first insulator stem with a first end and a second end, the first end being connected to the first arm; a first conductor holder connected to the second end of the first insulator stem; a second arm hingedly connected to the arm hub; a second insulator stem with a first end and a second end, the first end being connected to the second arm; a second conductor holder connected to the second end of the second insulator stem. 
         [0009]    Various embodiments include conductor lifts with additional features including, without limitation:
       a first arm gear rotably connected to the arm hub and connected to the first arm; and a second arm gear rotably connected to the arm hub and connected to the second arm, wherein the first gear arm and the second gear arm are connected so that angular movement of one of first or second arm gear causes angular movement of the other of first or second arm gear in the opposite direction.   a position of the first insulator stem that is selectively adjustable along at least a portion of the first arm.   a position of the second insulator stem that is selectively adjustable along at least a portion of the second arm.   a plurality of positioning holes defined in the first arm and configured so that the position of the first insulator mount along the first arm can be selected by engagement of the first insulator mount with one of the plurality of holes; and a first insulator mount attached to the first end of the first insulator stem, wherein the first insulator mount is configured to selectively engage one or more of the adjustment holes.   first arm and second arms comprising an insulating material configured to hinder the conduction of electrical current through said arm.   a first mount extender connecting the first insulator mount to the first insulator stem and configured to position the first conductor holder at a farther distance from the first arm.   a second mount extender connecting the second insulator mount to the second insulator stem and configured to position the second conductor holder at a farther distance from the second arm.   an articulation plate with a boom edge generally opposed to a lift edge and a lower edge generally opposed to an upper edge, wherein the articulation plate is rotably connected to the lifter plate at a position near an intersection of the boom edge and the lower edge, and wherein a plurality of articulation selection holes are defined along the upper edge; and a link bar with a boom end and a lift end, connected at the boom end to the lift plate and configured to be connected at the lift end to one of the plurality of articulation holes.   a lock notch defined in the first arm gear; and a lock notch engaging member configured to engage the lock notch when the first arm gear is in a desired locked position thereby restricting angular movement of the first arm gear.   stowage brackets configured to be attached to the boom and to secure the conductor lift to the boom when in the stowed position.   a center insulator stem positioned between first insulator stem and second insulator stem and connected to one of the first arm, the second arm, or the arm hub; and a center conductor holder connected to the center insulator stem.   a desiccant positioned within the upper arm and configured to absorb moisture from within the upper arm.   a moisture detector configured to indicate when moisture within the upper arm exceeds a determined level.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments, wherein: 
           [0024]      FIG. 1  is a perspective view of a conductor lift. 
           [0025]      FIG. 2  is a closer view of a mounting assembly for a conductor lift. 
           [0026]      FIG. 3A  is a perspective view of a boom tip and mounting plate in a deployed position. 
           [0027]      FIG. 3B  is a perspective view of a boom tip and mounting plate in a stowed position. 
           [0028]      FIG. 4  is a side view of a mast and articulation plate assembly for a conductor lift. 
           [0029]      FIG. 5A  is a closer view of a mounting assembly and an arm hub for a conductor lift. 
           [0030]      FIG. 5B  is the view of  FIG. 5A  with certain components removed for clarify. 
           [0031]      FIG. 6  illustrates a locking mechanism for an arm hub. 
           [0032]      FIG. 7  is a perspective view of an arm for a conductor lift with a bracket, insulating stem and conductor holder. 
           [0033]      FIGS. 8A and 8B  illustrate an embodiment of a quick connection system for components of a conductor lift. 
           [0034]      FIG. 9A  is a side view of a mounting assembly and arm hub in a vertical position. 
           [0035]      FIG. 9B  is a side view of a mounting assembly and arm hub in a horizonal position. 
           [0036]      FIG. 10  is a perspective view of a conductor lift with arms in an intermediate position and with one hub cover removed. 
           [0037]      FIG. 11  is a perspective view of a conductor lift with arms in a closed position. 
           [0038]      FIG. 12  illustrates a conductor lift in a stowed position attached to a truck. 
           [0039]      FIG. 13  illustrates a conductor lift in a vertically-deployed position attached to a truck. 
           [0040]      FIG. 14  is an exploded view of a conductor lift. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]      FIG. 1  illustrates a conductor lift  10  incorporating aspects of the present inventions. The embodiment of conductor lift  10  illustrated in  FIG. 1  is generally configured to be used with three-phase 115 kV power distribution systems. The three-phase 115 kV embodiment is used throughout this description to illustrate the inventions. However, persons of ordinary skill in the art will appreciate that conductor lift  10  can be modified and sized for use with other power distribution systems, including, without limitation, systems with higher or lower voltages, two-phase systems, DC systems, systems including static lines, and systems using multiple conductors per phase. Additionally, although many disclosed features are especially well-suited for use with energized conductors, conductor lift  10  can also be used in non-energized situations. 
         [0042]    Conductor lift  10  is configured to be mountable on a boom  102  of a lift truck  100  (see  FIGS. 12 and 13 ) or similar device. Conductor lift  10  is preferably connected to boom  102  by mounting assembly  20 . Mounting assembly  20 —described in greater detail below in connection with FIG.  2 —provides several benefits including, without limitation, the ability to adjust the articulation of conductor lift  10  with respect to boom  102  and the ability to stow conductor lift  10  on a side of boom  102  when conductor lift  10  is not in use. Mounting assembly  20  is connected to arm hub  50  of conductor lift  10 . Arm hub  50  is described in greater detail in connection with  FIGS. 5A and 5B , below. 
         [0043]    Extending from arm hub  50  are upper arm  104 , lower arm  106 , and center insulating stem  108 . Upper arm  104  and lower arm  106  are preferably constructed from a strong material with a high electrical resistance, such as fiberglass. In the event that a conductor becomes loose and contacts upper arm  104  or lower arm  106 , the high electrical resistance material provides a length of insulation, which helps to prevent electricity from arcing back to boom  102 . However, upper arm  104  and lower arm  106  do not have to be insulating and can alternatively comprise other materials, including conductive materials such as steel, aluminum, or other metals, with or without external insulation. 
         [0044]    When configured for use in a three-phase 115 kV system, upper arm  104  and lower arm  106  are preferably between 10 and 16 feet long; more preferably between 14 and 15 feet long; and most preferably about 14.5 feet long. For use with other systems, upper arm  104  and lower arm  106  can be made shorter or longer, as appropriate. Alternatively, arm hub  50  can be positioned at a point other than the midpoint of conductor lift  10 , and upper arm  104  made a different length than lower arm  106 . In such embodiment, center insulating stem  108 , if used, is preferably positioned at or near the midpoint, rather than attached to arm hub  50 . 
         [0045]    An upper bracket  114  is attached to upper arm  104 . Upper bracket  114  is configured to be selectively positionable along upper arm  104 . Similarly, a lower bracket  116  is attached to and selectively positionable along lower arm  106 . In the illustrated embodiment, selective positioning is accomplished using holes  118  defined in upper arm  104  and lower arm  106  at increments between about 3 and 12 inches, and most preferably at about six inches. However, other methods for selective positioning are known and can be used. Alternatively, for applications in which adjustive positioning is unnecessary, upper bracket  114  and lower bracket  116  can be attached at fixed positions. 
         [0046]    In the illustrated embodiment, extenders  122 ,  123  are shown attached to upper bracket  114  and lower bracket  116 , respectively. At a distal end of extender  122  from upper bracket  114  is upper insulating stem  124 . At a distal end of extender  123  from lower bracket  116  is lower insulating stem  126 . Wire holders  132  (or any other conductor-holding device) are secured at a distal end of each of upper insulating stem  124 , center insulating stem  108 , and lower insulating stem  126 . Alternatively, depending on the conductor configuration, extenders  122 ,  123  can be removed so that upper insulating stem  124  connects directly to upper bracket  114  and lower insulating stem  126  connects directly to lower bracket  116 . Upper bracket  114  and lower bracket  116  preferably comprise quick disconnect sockets (see  FIGS. 8A and 8B ) configured to hold extenders  122  and  123  or insulating stems. Similarly, extenders  122  and  123  preferably comprise compatible quick disconnect sockets configured to hold insulating stems. In an alternative embodiment, if a conductor lift will not be used for work on energized conductors, insulating stems are not necessary and can be omitted or replaced by non-insulating components. 
         [0047]      FIG. 2  is a closer view of mounting assembly  20 . Mounting assembly  20  comprises adapter plate  212 , articulation plates  228 , and link bars  232  or  234  (see  FIG. 3B ). Adapter plate  212  comprises attachment tabs  214 , which correspond to boom tip tabs  204  on boom tip  202 . Adapter plate  212  is secured to boom tip  202  by attachment pins  216  placed through holes defined in attachment tabs  214  and boom tip tabs  204 . Removing two attachment pins  216  from one side of mounting assembly  20  allows adapter plate  212  and conductor lift  10  to rotate between a use position and a stowed position. 
         [0048]    Adapter plate  212  preferably comprise an upper pivot point  224  and a lower pivot point  226 . Lower pivot point  226  is rotatably attached to pivot holes  404  (see  FIG. 4 ) defined in articulation plates  228 . A vertical link bar  232  or a horizontal link bar  234  are rotatably attached at one end to upper pivot point  224  and at the other end to articulation plate  228 . As shown in  FIG. 9A , for vertical configuration of conductor lift  10 , vertical link bar  232  is preferably a slotted bar. As shown in  FIG. 9B , for horizontal configuration of conductor lift  10 , horizontal link bar  234  is preferably a shorter bar with holes defined near each end. 
         [0049]      FIG. 3A  is a closer view of boom tip  202  and adaptor plate  212 . Boom tip tabs  204  extend from each side of boom tip  202 . Boom tip  202  and boom tip tabs  204  are preferably existing features on boom  102 . Attachment tabs  214  extend from adaptor plate  212  and align with boom tip tabs  204 . Adaptor plate  212  is secured to boom tip  202  by placing attachment pins  216  through holes defined in boom tip tabs  204  and attachment tabs  214 . 
         [0050]      FIG. 3B  illustrates boom tip  202  and adaptor plate  212  in an alternative configuration. In this view, two attachment pins  216  have been removed, allowing adaptor plate  212  to hingedly rotate and place conductor lift  10  alongside boom  212 . In this configuration, a stow latch  302  comprising a stow bar  304  engages boom slots  312 . 
         [0051]      FIG. 4  shows a closer view of mast  230  and articulation plate  228  with one possible configuration of link attachment points  402  and pivot holes  404 . Link attachment points  402  represent holes defined in articulation plates  228 . By connecting vertical link bar  232  or horizontal link bar  234  to a particular link attachment point  402 , the orientation of conductor lift  10  with respect to boom  102  can be selected. Preferably, vertical link bar  232  is attached to a link attachment point  402  with a “V” (vertical) symbol, while horizontal link bar  234  is attached to a link attachment point  402  with an “H” (horizontal) symbol. At least one link attachment point  402  preferably corresponds to a stowed position using vertical link bar  232 , horizontal link bar  234 , or a special stow link bar (not shown). 
         [0052]    Components of mounting assembly  20  are preferably made of metal such as steel for durability and strength. Alternatively, certain components, such as articulation plates  228  and adapter plate  212  can comprise non-conducting material to reduce the risk of undesired transmission of electric current. 
         [0053]      FIG. 5A  provides another view of mounting assembly  20 . Mounting assembly  20  also comprises arm hub  50 . Arm hub  50  comprises hub covers  502 , which provide a physical barrier to protect users from the moving parts within. 
         [0054]      FIG. 5B  shows arm hub  50  with one hub cover  502  and one articulation plate  228  removed for clarity. Between articulations plates  228  is mast  230 . Mast  230  is preferably welded to articulation plates  228 , so that two or more articulation plates  228  and mast  230  function as a single part in the assembled device. At arm hub  50 , upper arm  104  is attached to upper arm crank  504  and lower arm  106  is attached to lower arm crank  506 . Upper arm crank  504  and lower arm crank  506  are each hingedly connected to mast  503 . 
         [0055]    Upper arm crank  504  comprises upper gear teeth  514 . Lower arm crank  506  comprises lower gear teeth  516 . Upper gear teeth  514  and lower gear teeth  516  are interconnected so that angular movement of lower arm  106  with respect to arm hub  50  will cause an analogous angular movement of upper arm  104  in the opposite direction. The mechanical linking of upper arm  104  and lower arm  106  facilitates deploying and stowing of conductor lift  10 , allowing convenient manual manipulation without powered assistance. 
         [0056]    Preferably, upper arm crank  504  and lower arm crank  506  are configured so that, at one extreme end of a prescribed range of motion, upper arm  104  and lower arm  106  will appear to form a single straight shaft. At an opposite extreme end of the prescribed range of motion, upper arm  104  and lower arm  106  are preferably substantially parallel and adjacent (See  FIG. 11 ). 
         [0057]    Additionally, as illustrated in  FIG. 10 , upper arm  104  and lower arm  106  can be positioned at an intermediate alignment. In this configuration, wire holders  132  attached to upper arm  104  and lower arm  106  can engage offset conductors without the use of extenders  122 ,  123 . 
         [0058]      FIG. 6  shows arm hub  50  with one articulation plate  228  and mast  230  removed to show a a locking mechanism that can be used with arm hub  50 . When upper arm  104  is in a desired position (e.g. fully opened or in an intermediate alignment), a sliding pin  602  engages a notch  604  defined in upper arm crank  504 . Sliding pin  602  is held in place by cam  608 , rocker arm  612 , and spring  614 . Sliding pin  602  prevents rotation of upper arm  104  and lower arm  106 , until sliding pin  602  is released by pulling on rocker arm  612 . A locking pin  616  prevents movement of rocker arm  612  and prevents accidental disengagement of sliding pin  602 , e.g. due to spring  614  failure. Alternatively, other locking mechanisms are known and could be used. 
         [0059]      FIG. 7  is a closer view of upper arm  104 , upper bracket  114 , upper insulating stem  124 , and wire holder  132 . Near the upper end of upper arm  104  is a dessicant canister  702 . Dessicant canister  702  plugs the upper arm  104  and contains a dessicant material which absorbs moisture from the interior of upper arm  104 . Dessicant canister  702  also preferably functions as a moisture indicator by comprising at least one moisture-sensitive element that changes color when moisture is present within upper arm  104 . Preferably, a similar dessicant and moisture indicator system is provided for lower arm  106 . 
         [0060]      FIGS. 8A and 8B  illustrate one embodiment of a quick connect system. A connection plate  802  is attached to insulating stem  122 . Connection plate  802  comprises connection loops  804 . Receiver plates  812  are attached to wire holder  132 . Receiver plates  812  comprise receiver slots  814 , which are configured to align with connection loops  804  so that connection loops  804  extend through receiver slots  812  when a receiver plate  812  is adjacent connection plate  802 . Wire holder  132  can be quickly secured to insulating stem  124  by inserting a u-bar  822  through connection loops  804  and securing the u-bar  822  in place with fasteners such as threaded nuts. Wire holder  132  preferably comprises two orthogonally-oriented receiver plates  812  to allow installation of wire holder  132  either vertically or horizontally with respect to insulating stem  124 . Preferably, compatible quick connect systems are used to connect all extenders, insulating stems, and wire holders. 
         [0061]      FIGS. 9A and 9B  illustrate conductor lift  10  in vertical and horizontal alignments, respectively, with respect to boom  102 .  FIG. 9A  includes vertical link bar  232 , while  FIG. 9B  includes horizontal link bar  234 . 
         [0062]      FIG. 10  illustrates upper arm  104  and lower arm  106  positioned in an intermediate (offset) alignment. 
         [0063]      FIG. 11  illustrates conductor lift  10  in a folded position. In the folded position, upper arm  104  and lower arm  106  are generally parallel to each other. A link mechanism  902  can be used to maintain this relationship. 
         [0064]      FIG. 12  shows conductor lift  10  in a stowed position. Upper arm  104  and lower arm  106  are also parallel to boom  102 . Attachment sockets (not shown) preferably secure upper arm  104 , lower arm  106 , or both, to boom  102  when conductor lift  10  is stowed. In  FIG. 12 , adaptor plate  212  is shown as still connected on one side to boom tip  202 . Alternatively, adaptor plate  212  can be fully disconnected from boom tip  202  and be supported by boom slots  312  and attachment sockets. Further alternatively, after adaptor plate  212  is fully disconnected from boom tip  202 , conductor lift  10  can be removed from lift truck  100  for storage or for use at another location. 
         [0065]      FIG. 13  shows conductor lift  10  in a deployed position ready for use. 
         [0066]      FIG. 14  is an exploded view of a conductor lift illustrating various components. 
         [0067]    Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions, will be apparent to persons skilled in the art upon reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.