Abstract:
A warning sign for a utility pole includes a layer manufactured in curved or tubular form. The warning sign returns to such form when flattened having acquired a memory of that form through manufacture. A tool for installing the warning sign about a utility pole is also described.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to warning signs. More particularly, the present invention relates to warning signs of the variety required in some jurisdictions to be placed on the cross arms or upright portions of utility poles supporting electric power lines. Specifically, regulatory requirements in some jurisdictions dictate that the term “HIGH VOLTAGE” be affixed to the cross arms or upright portions of utility poles in order to warn utility workers and the general public of the danger of high voltage.  
         [0003]     2. Description of the Prior Art  
         [0004]     At present, the signs used for the above noted purpose are typically flat metal or plastic signs bearing the terminology “HIGH VOLTAGE”. The signs are attached to both sides of the cross arm either in the maintenance yard when the pole is being assembled or on-site when the pole is being disposed at a desired location. Signs of this type hold up for a time under ambient conditions, but eventually fall off, fall into disrepair or fade due to weather conditions, especially exposure to sunlight, and must be replaced.  
         [0005]     Replacement typically requires a lineman to climb the pole or to use a bucket-lift truck to reach the level of the cross arm to install a new sign, generally with hammer and nails or some other suitable fastening means. Before this can be done, the lineman must cover all of the live wires and other components within close proximity to the sign with an insulating rubber blanket to protect himself and others from the danger of electrocution. While prudent, this safety procedure takes additional time and adds to the labor costs of the utility.  
         [0006]     The present invention provides warning signs for installation and replacement around a pole supporting electric power lines rather than the cross arms. The warning signs may be installed and replaced from ground level without requiring a lineman to ascend to the level of electrically live components, thereby lowering labor costs and reducing the risk of electrocution.  
       SUMMARY OF THE INVENTION  
       [0007]     Accordingly, the present invention is a warning sign for a utility pole. The warning sign comprises at least two layers, namely, a first layer and a second layer.  
         [0008]     The first layer is a coextruded sheet, preferably of a high-density polyethylene with ultraviolet inhibitors. The coextruded sheet making up the first layer has two sublayers, each being of a different color. Text, such as a warning message including the words “HIGH VOLTAGE”, is engraved into one of the two sublayers to a depth exposing the other of the two sublayers. The text then appears in the color of one sublayer surrounded by the color of the other sublayers.  
         [0009]     A second layer is attached to the first layer on a side opposite to the text. The second layer, as a consequence of its manufacture, has a tendency to return to a curved or tubular shape after being flattened, because it is manufactured in a curved shape and has memory to return to and maintain such a shape. As a consequence of this characteristic of the second layer, the warning sign remains clamped about a utility pole once installed there. The second layer is preferably of a fiberglass sheet material.  
         [0010]     Because fiberglass sheet material is difficult to handle without adequate hand protection, as glass fibers tend to penetrate and irritate the skin, the warning sign preferably has a third layer attached to the first and second layers on the side of the second layer opposite to the first layer. The third layer is preferably of a high-density polyethylene with ultraviolet inhibitors. When the warning sign is in its relaxed tubular form, the first, second and third layers are outer, middle and inner layers, respectively, with the middle, fiberglass layer being protected from the elements by the outer and inner layers between which it is sandwiched.  
         [0011]     The present invention also includes a tool for installing the warning sign about a utility pole. The tool includes a rod, preferably of a non-conducting material. The rod may be as much as forty feet in length, and may be telescoping for convenience. At one end of the rod is a cross member extending in opposite directions therefrom. The cross member is generally arcuate in shape, and has an inside face on the concave side thereof and a first end and a second end.  
         [0012]     A pivot arm is disposed at each of the first and second ends of the cross member on the inside face. The pivot arms are separated from the inside face by gaps. For installation, the warning sign is outstretched against the inside face and inserted in the gaps.  
         [0013]     The tool finally includes means to rotate the pivot arms from a distance to release the warning sign to close into a curved state around a utility pole.  
         [0014]     The present invention will now be described in more complete detail with frequent reference being made to the figures identified below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a plan view of the warning sign of the present invention in a flattened state;  
         [0016]      FIG. 2  is a cross-sectional view of the warning sign taken as indicated in  FIG. 1 ;  
         [0017]      FIG. 3  is a top plan view of the warning sign in a relaxed state;  
         [0018]      FIG. 4  is a plan view of the rear of the tool of the present invention;  
         [0019]      FIG. 5  is a plan view of the front of the tool;  
         [0020]      FIG. 6  is a plan view of the front of the tool with the warning sign held in place;  
         [0021]      FIG. 7  is a perspective view of the tool with warning sign in place;  
         [0022]      FIG. 8  is a perspective view of the tool and warning sign in position to install the warning sign about a utility pole;  
         [0023]      FIG. 9  is a perspective view of the warning sign installed on a utility pole; and  
         [0024]      FIG. 10  is a perspective view of the warning sign installed on a utility pole from the opposite direction from that of  FIG. 9 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     Turning now to these figures,  FIG. 1  is a plan view of the warning sign  10  of the present invention in a flattened state.  FIG. 2  is a cross-sectional view taken as indicated in  FIG. 1 . Warning sign  10  comprises three layers: an outer layer  12 , a middle layer  14  and an inner layer  16 . The designations outer, middle and inner, of course, are made with reference to the locations of the layers in the warning sign  10  in its unflattened state.  
         [0026]     Turning first to the outer layer  12 , outer layer  12  is formed from a coextruded high-density polyethylene sheet, preferably including ultraviolet inhibitors. Outer layer  12  is coextruded in two sublayers, an outer sublayer  12   a  and an inner sublayer  12   b,  each of its own color. Top sublayer  12   a  is typically of yellow pigmentation and bottom sublayer  126  is typically of black pigmentation, although other color combinations may be used. After extrusion, the text  18 , such as “VOLTAGE HIGH VOLTAGE HIGH” as shown in  FIG. 1 , is engraved using an engraving or routing machine into the coextruded outer layer  12  by removing discrete portions of the outer sublayer  12   a  to reveal the inner sublayer  12   b  in the form of letters. That the desired text is provided by engraving a coextruded sheet, not a laminated sheet, to remove an outer sublayer  12   a  of one color to reveal an inner sublayer  12   b  of another color ensures that the outer layer  12  will not peel apart, and that the engraved text will not be worn off, due to inclement conditions. In the cross-sectional view of  FIG. 2 , two portions  20  of the letter “O” are shown to be removed from outer sublayer  12   a.    
         [0027]     Middle layer  14  is of a curved fiberglass sheet material manufactured in a manner that provides it with shape memory and enables it to return to a curved form after being flattened. Typically, the curvature would be that of a circle of a diameter less than that of a utility pole, so that the middle layer  14  would enable the warning sign to clamp firmly around the pole. Typically, that diameter would be on the order of 7.5 inches, although the present invention is not to be taken to be limited to such a value. It follows that the warning sign  10  will be at least approximately 2.0 feet long in order to completely wrap around and clamp to a utility pole of diameter greater than 7.5 inches.  
         [0028]     The use of non-conductive fiberglass has obvious advantages in the present context, but it may be difficult to handle without proper hand protection, namely gloves, to prevent fine glass fibers from irritating the skin. For this reason, the warning sign  10  also includes an inner layer  16 . Inner layer  16  is extruded from high-density polyethylene, preferably including ultraviolet inhibitors. Typically, inner layer  16  is of black pigmentation, although it may be of any color. The presence of the inner layer  16  makes it easier for those not wearing gloves to handle the warning sign  10 , as the fiberglass middle layer  14  is between the polyethylene outer and inner layers  12 ,  16 . Moreover, this sandwich design shields the fiberglass material from direct exposure to sunlight, thereby prolonging the useful life of the warning sign  10 .  
         [0029]     The three layers  12 ,  14 ,  16  of the warning sign  10  are held together in the form of a sandwich by non-corrodible rivets  22 , made, for example, of aluminum. The complete warning sign  10  is very strong and requires considerable arm and hand strength to be opened and placed around a utility pole, as well as to be removed from a utility pole about which it has been installed.  
         [0030]      FIG. 3  is a top plan view of the warning sign  10  when allowed to relax to the curved state given to the middle layer  14 . Rivets  22  are at the middle and both ends of the warning sign  10 . The warning sign  10  is relaxed to its characteristic diameter D, and will clamp firmly to a utility pole of greater diameter, and, it follows, the greater the diameter of the pole, the stronger the clamp. There may be some overlap between the two ends of the warning sign, but, essentially, the message “HIGH VOLTAGE” will be visible from any point around the pole.  
         [0031]      FIG. 4  is a plan view of the rear of the tool  30  for installing the warning sign  10 , and  FIG. 5  is a plan view of the front of the tool  30 . The tool  30  includes a rod  32 , which may be telescoping and be extendable for as much as 40 feet. Preferably, rod  32  is made of fiberglass or some other material which does not conduct electricity.  
         [0032]     Attached to the end of the rod  32  is a cross member  34  extending in opposite directions from rod  32 . Cross member  34  is preferably arcuate in shape, and has a first end  36  and a second end  38 . On the inside face  40  of the cross member  34 , the inside face  40  being the concave side of the arcuate cross-member  34 , at each of the first and second ends  36 ,  38  is a pivot arm  42 , each of which is separated from inside face  40  by a gap  44 . Inside face  40  may be covered by an insulating and low-friction material, such as a high-density polyethylene.  
         [0033]     A cable  46  runs from the end of one pivot arm  42  to a first fixed pulley  48  on the rear side of the cross member  34 ; around the first fixed pulley  48  to a movable pulley  50 ; around the movable pulley  50  to a second fixed pulley  52  adjacent to the first fixed pulley  48  on the rear side of the cross member  34 ; around the second fixed pulley  52  and thence to the end of the other pivot arm  42 . A rope  54 , preferably of a non-conductive material, is attached to the movable pulley  50  and extends along rod  32 , so that it may be pulled by one holding the bottom end of the rod  32 . When rope  54  is so pulled, movable pulley  50  is pulled by rope  54  and, in turn, pulls on cable  46  from the middle thereof, ultimately pulling pivot arms  42  to orientations toward first and second fixed pulleys  48 ,  52 .  
         [0034]     Referring now to  FIGS. 5 and 6 , the latter of which shows warning sign  10  installed on tool  30 , warning sign  10  is installed on tool  30  by flattening it to some extent, and inserting it into the gaps  44  between pivot arms  42  and the inside face  40  of cross member  34 .  
         [0035]      FIG. 7  is a perspective view of tool  30  with warning sign  10  in place ready to be installed about a utility pole. Essentially, pivot arms  42  at the first and second ends  36 ,  38  of the arcuate-shaped cross member  34  maintain the warning sign  10  in a semi-opened C-shape, which can contain the utility pole about which the warning sign  10  is to be installed.  FIG. 8  is a perspective view showing the tool  30  holding warning sign  10  in such a position. When rope  54  is pulled by the installer on the ground near the base of utility pole  50 , pivot arms  42  assume the positions described above, releasing the warning sign  10  and allowing it to spring closed about the utility pole  50 .  
         [0036]     The result is shown in the perspective views of the installed warning sign  10  in  FIGS. 9 and 10 , the former showing the warning sign  10  from the side of the utility pole  50  where the tool  30  had been placed, the latter showing the warning sign  10  from the far side of the utility pole  50  where the ends of the warning sign  10  overlap one another, as shown in  FIG. 3 .  
         [0037]     Prior to installation, a pressure-sensitive adhesive may be applied to the inner layer  16  of the warning sign  10  to bond the warning sign  10  to the utility pole  50 .  
         [0038]     Modifications to the above would be obvious to those of ordinary skill in the art, but would not bring the invention so modified beyond the scope of the appended claims.