Abstract:
A warning sign for mounting on a structural member, such as a cross arm of a utility pole, has an elongated U-shaped support member and a warning message disposed thereon. The warning sign is installed on the structural member by a utility worker at ground level by pushing it upward onto the structural member, about which it locks and cannot be easily removed. The support member and warning message are preferably extruded from high-density polyethylene which includes ultraviolet (UV) inhibitors.

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 of all utility poles mounted immediately adjacent to electrical power lines. Regulatory requirements dictate that the term “High Voltage” be affixed to both sides of the cross arms 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 enables warning signs of this type to 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 utility pole warning sign which may be installed by a utility work onto the cross arm of a utility pole from ground level. The warning sign comprises an elongated U-shaped support member which is adapted to fit around a cross arm of a utility pole and remain there more or less permanently, and a warning message on at least one of two sides of the support member.  
         [0008]     In brief, the support member, which is extruded, preferably from a high-density polyethylene having ultraviolet (UV) inhibitors, has a base, a first side, a second side and an interior between the first and second sides, all in the manner of a U-shape. The base has a fin extending therefrom in a direction away from the first and second sides. The fin is provided to enable a utility worker to grasp the warning sign with a tool, such as a hot stick, and may have one or more holes extending transversely therethrough to facilitate such manipulation.  
         [0009]     The first side and the second side each extend from the base to top ends having a first oblique member and a second oblique member, respectively. The first and second members are inclined toward the interior of the support member, so as to direct the cross arm of a utility pole into the interior of the support member and to separate the first and second sides from one another when the warning sign is pushed upward against the cross arm. The first and second sides each have an inner end which extends inward of the first and second sides, respectively, toward the interior of the support member. When the support member is pushed upward so as to completely cover the cross arm, the inner ends of the first and second oblique members extend over the cross arm and prevent the removal of the warning sign therefrom.  
         [0010]     The warning message is disposed on one or both of the first and second sides, where it may be held by an adhesive, rivets, screws or be slidingly received by upper and lower slot members. The warning message is preferably a coextruded sheet having two layers, each of which is of a different color, the warning message having text engraved into one of the two layers to a depth exposing the other of the two layers. Preferably, the warning message is coextruded from high-density polyethylene having ultraviolet (UV) inhibitors, one layer being of a yellow color and the other being of a black color, so that, when the text is engraved, it appears as black letters on a yellow background.  
         [0011]     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  
       [0012]      FIG. 1  is a cross-sectional view of the elongated U-shaped support member of the present utility pole warning sign;  
         [0013]      FIG. 2  is a cross-sectional view of the utility pole warning sign disposed on a cross arm;  
         [0014]      FIG. 3  is a plan view of a warning message which may be mounted on the support member;  
         [0015]      FIG. 4  is a cross-sectional view of the warning message taken as indicated in  FIG. 3 ; and  
         [0016]      FIG. 5  is a perspective view of the utility pole warning sign disposed on a cross arm. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Turning now to these figures,  FIG. 1  is a cross-sectional view of the elongated U-shaped support member  10 . Support member  10  is extruded from a high-density polyethylene, preferably having ultraviolet (UV) inhibitors, in dimensions capable of accommodating a cross arm on a utility pole. The support member  10  has a base  12 , a first side  14  and a second side  16 . Extending from and below the base  12  is a fin  18  which has one or more holes, not visible in  FIG. 1 , by which the support member  10  may be held by and manipulated with a hot stick. The latter is a tool commonly used by electrical utility workers, and has an extendable pole with a ratchet-type jaw. The hot stick pole is of a material which does not conduct electricity, enabling a worker using it to perform many tasks on or near electrical cables from a safe distance and without danger of electrical discharge.  
         [0018]     The first side  14  and second side  16  of the support member  10  extend upward from the base  12  away from the fin  18  and form the two sides of its U-shape. The first and second sides  14 ,  16  are inclined somewhat toward one another for reasons to be made clear below. At the top end of each of the first and second sides  14 ,  16  are oblique members  20 ,  22 . First oblique member  20  is at the top end of first side  14 ; second oblique member  22  is at the top end of second side  16 . Oblique members  20 ,  22  are inclined toward the interior of the U-shaped support member  10 .  
         [0019]     On the outside of the first and second sides  14 ,  16  are upper and lower longitudinal slot members  24 ,  26  which are designed to slidably accommodate warning messages. Slot members  24 ,  26  are optional and may be omitted, in which case the warning messages are affixed to the first and second sides  14 ,  16  in another manner, such as by rivets, screws or an adhesive.  
         [0020]      FIG. 2  is a cross-sectional view of the utility pole warning sign  30  installed on a cross arm  32 , also viewed in cross section, of a utility pole. Below the cross arm  32 , grounding cables  34 , shown in cross section, may be present. Elongated U-shaped support member  10  is provided in dimensions to accommodate any grounding cables  34  along with cross arm  32 .  
         [0021]     It will be immediately noted that first and second sides  14 ,  16  are more parallel to one another in  FIG. 2  than appears in  FIG. 1 . As the support member  10  is extruded in the form shown in  FIG. 1 , first and second sides  14 ,  16  have a natural tendency to spring back toward their relative positions in  FIG. 1  when separated. Therein lies the operation of the support member  10  when installed on a cross arm  32 .  
         [0022]     When installing utility pole warning sign  30  of the present invention, warning messages  36 , preferably of the variety to be described below, are slidably inserted between upper and lower longitudinal slot members  24 ,  26  on first and second sides  14 ,  16 , or otherwise attached thereto. Then a utility worker grasps the warning sign  30  with a hot stick using fin  18  of support member  10 . Raising the warning sign  30  up to the cross arm from below with the hot stick, the utility worker forces oblique members  20 ,  22  against the bottom of the cross arm  32 . Because of their oblique orientation toward the interior of the U-shaped support member  10 , this action tends to force the first and second sides  14 ,  16  apart in a wedge-like fashion so that cross arm  32  slips between the inner ends  28  of the oblique members  20 ,  22 . Warning sign  30  is then forced completely up over cross arm  32  until inner ends  28  reach the top of the cross arm  32 , at which point first and second sides  14 ,  16  snap back toward one another to the positions shown in  FIG. 2 , leaving inner ends  28  above the cross arm  32 . With the oblique members  20 ,  22  now oriented obliquely downward toward the cross arm  32 , the utility pole warning sign  30  cannot be easily removed from the cross arm  32 .  
         [0023]      FIG. 3  is a plan view of a warning message  36 .  FIG. 4  is a cross-sectional view thereof taken as indicated in  FIG. 3 . Warning message  36  is formed from a coextruded high-density polyethylene sheet, preferably including UV inhibitors. Warning message  36  is extruded in two layers, each of its own color. Top layer  38  is typically of yellow pigmentation and bottom layer  40  is typically of black pigmentation, although other color combinations may be used. After extrusion, the text, such as ‘HIGH VOLTAGE” as shown in  FIG. 3 , is engraved into the coextruded sheet by removing discrete portions of the top layer  38  to reveal the bottom layer  40  in the form of letters. That the desired text is provided by engraving a coextruded sheet, not a laminated sheet, to remove a top layer  38  of one color to reveal a bottom layer  40  of another color ensures that the warning message  36  will not peel apart or wear off due to inclement conditions.  
         [0024]     It will be noted that warning message  36  includes round holes  42  and slotted holes  44  which may be used to attach warning message  36  to a support member  10  not having slot members  24 ,  26  with screws or rivets. Slotted holes  44  ensure that the warning message  36  will not buckle when the weather is hot; in other words, the slotted holes  44  allow for the expansion of the warning message.  
         [0025]     Warning message  36  may also be perforated or scored along line  46  to permit its ready separation into two smaller parts. This may be useful where a cross arm extends an insufficient distance from a utility pole to mount the warning sign  30 . In that event, warning message  36  may be cut into two pieces along line  46  so that one piece could be positioned on the cross arm on one side of the pole and the other piece on the cross arm on the other side of the pole to provide the necessary warning. In such a situation, support member  10  is also cut into two pieces of appropriate length to mount the two pieces of warning message  36  on opposite sides of the pole.  
         [0026]      FIG. 5  is a perspective view of the utility pole warning sign disposed on a cross arm as shown in  FIG. 2 . Fin  18  has holes  48  to facilitate the handling of the utility pole warning sign  30  with a hot stick. Oblique members  20 ,  22  may also have holes  50  for this purpose.  
         [0027]     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.