Abstract:
A tamper-resistant marker is formed of metal sheet material from a substantially planar blank thereof having a perimeter and two faces. The marker has a flange extending therefrom about the perimeter in a direction substantially perpendicular to the faces. The marker also has indicia with raised portions on one of the two faces, the raised portions being raised in a direction opposite to that of the flange. Methods of manufacturing the marker and of mounting it on a surface are also disclosed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to the marking of storm drains to alert members of the public to the dangers in dumping detrimental materials into waterways. More specifically, the invention relates to a tamper-resistant marker for this purpose and to a method of mounting the marker.  
         [0003]     2. Description of the Prior Art  
         [0004]     The U.S. Environmental Protection Agency (EPA) has directed the states to develop programs to educate the public about the dangers to the environment when materials that are harmful to the health and safety of living organisms are dumped into streets and driveways, eventually to be washed to storm drains to enter rivers, streams, and other waterways and, possibly, our drinking water system.  
         [0005]     The education program includes the marking of storm drains which lead from roadways and ultimately to waterways. Currently, several methods are used to carry out this marking.  
         [0006]     Firstly, stencils have been commonly used to apply a warning message to the surface of concrete or asphalt near the storm drain. However, the paints used typically weather poorly and have to be redone every few years. The spray painting itself is time consuming, and cannot be done in wet or cold weather, or in windy conditions. Moreover, the paint vapors are potentially harmful to the user. The resulting prints are messy, and leave a message less clear than desirable.  
         [0007]     Alternatively, ceramic tile markers, which have been screen-printed with an appropriate message and glazed, may be applied with adhesives and cemented in place. Ceramic tile markers, however, are easy to crack in use and are expensive. Flat cast or metal markers have also been used in the past. These have good life expectancy, but are expensive to manufacture and difficult to read. Because of their flat backs, they often fail to adhere to the adhesives.  
         [0008]     Finally, plastic domed markers are most often used to identify storm drains. They are made of a base material, such as vinyl or polycarbonate, screen-printed with an appropriate message, and die-cut into shape. The resulting blank is covered with a polyurethane coating having ultraviolet (UV) inhibitors to protect against damage caused by exposure to sunlight. This heavy, syrup-like coating flows to the edge of the blank and hardens. The resulting product has graphics under a clear plastic dome that thins near the edges. Adhesives, like liquid nails, may be used to apply the markers to various surfaces.  
         [0009]     There are several problems associated with these plastic domed markers. Firstly, exposure to direct sunlight causes embrittlement in plastics. Secondly, daily temperature variations often cause the adhesive to fail on the undersurface of the marker because the flat vinyl surface is smooth and offers little bond to the adhesive. Finally, colorful, domed plastic markers are attractive and easily pried from the surfaces to which they are attached by vandals and others who like to collect them. A penknife or small screwdriver is all that is required for this purpose, as the plastic domed markers are flexible and can readily be peeled from the surface to which they are applied once an edge is exposed.  
         [0010]     The present invention is directed toward these shortcomings of the prior art and provides a tamper-resistant marker which cannot be as readily removed from a surface as those of the prior art.  
       SUMMARY OF THE INVENTION  
       [0011]     Accordingly, the present invention is a tamper-resistant marker which comprises a blank made of metal sheet material. The blank is substantially flat and has a perimeter, two faces, and a flange extending therefrom about the perimeter in a direction substantially perpendicular to the faces. The blank also had indicia with raised portions on one of the two faces. The portions in question are raised in a direction opposite that of the flange. The areas between the raised portions may be painted to make the indicia more visible or legible, as the case may be.  
         [0012]     As will be discussed below, the marker is mounted on a surface by cutting a groove thereinto having the shape of the flange extending around the perimeter of the blank. The flange resides in the groove below the level of the surface when mounted, making it difficult for a vandal to remove the marker.  
         [0013]     The present invention also includes a method for manufacturing the tamper-resistant marker. The method comprises the steps of providing a blank of sheet metal, the blank having two faces and a perimeter, and of embossing indicia having raised portions onto one of the two faces of the blank. The method finally includes the step of forming a flange about the perimeter in a direction substantially perpendicular to the faces and in a direction opposite to that of the raised portions of the indicia.  
         [0014]     Finally, the present invention includes a method of mounting the tamper-resistant marker on a surface. The method comprises the step of providing a marker having a substantially planar face and having a perimeter with a flange extending therefrom in a direction perpendicular to the face. The method also includes the step of cutting a groove into the surface onto which the marker is to be mounted. The groove conforms to the perimeter of the marker to accommodate the flange when the marker is installed on the surface.  
         [0015]     Finally, an adhesive is applied onto the surface within the area defined by the groove, and the marker is pressed into the adhesive with the flange disposed in the groove.  
         [0016]     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  
       [0017]      FIG. 1  is a plan view of a marker of the present invention;  
         [0018]      FIG. 2  is a cross sectional view of the marker taken as indicated in  FIG. 1 ;  
         [0019]      FIG. 3  is a perspective view of a hole saw having a coaxial drill;  
         [0020]      FIG. 4  is a partly cross-sectional, partly perspective view of a marker when installed; and  
         [0021]      FIG. 5  is a perspective view of an installed marker. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]     Turning now to these figures,  FIG. 1  shows a plan view of a marker  10  of the variety used in the practice of the present invention.  FIG. 2  is an enlarged cross section thereof taken as indicated in  FIG. 1 .  
         [0023]     The marker  10  is made of a metal, such as aluminum, brass or stainless steel, in heavy, 16-gauge (0.060-inch thick), blank sheets. Embossing dies form the flat blanks into deep three-dimensional disks or plates with raised copy, such as that on marker  10 . A high tonnage power press, rated at 400 tons, is used for this purpose. The embossing adds strength to the metal material, often equivalent to doubling its thickness.  
         [0024]     After embossing, the oversized plate is placed upon a blanking die that forms a dome, drawing the sides of the blank rearward to form an approximately 0.125-inch-deep dish- or cup-like shape just before it cuts the round blanks. The flange  12  formed in this operation is shown in  FIG. 2 , along with the embossed pattern  14 , which is what may be seen of the design shown in  FIG. 1  when viewed in cross section.  
         [0025]     The shaped blanks, which may, for example, be 4.0-inch-diameter disks, are then deburred by sanding the cut edges or tumbling the disk in an abrasive medium.  
         [0026]     After cleaning, the disks are placed upon an anvil nest and an abrasive pad, scotchbrite or emery cloth is rotated upon the face, to give a prism-spin appearance that reflects light and gives a high-quality appearance to the disk. At the same time, this operation applies a fine, uniform circular scratch to the surface and background of the disk which improves the adhesion of paint to be applied thereon.  
         [0027]     A baking enamel containing ultraviolet inhibitors is spray-painted onto the surface and, while still wet, the plate is placed upon a conveyor belt that transports the product under a series of rollers having a solvent-absorbing paper to remove the wet paint from the raised portions of the embossed surface leaving the background in a painted and contrasting color. Alternatively, the paint may be removed from the raised portions of the embossed surface after curing with an abrasive sanding disk.  
         [0028]     The plate is then baked at high temperatures to cure the paint and make it hard.  
         [0029]     Alternatively, the flat blanks may be screen-printed with a color-contrasting background prior to embossing in registration with the screen-printed background. One or more colors may be applied in this manner. The blank may also be baked prior to the embossing step in this alternative.  
         [0030]     The resulting finished product is distinctive, easy to read, has a high-quality appearance and, when compared to any other existing storm drain marker, gives the appearance of a product of much higher cost. The product with embossed-copy permanence has a life expectancy of more than thirty years, that is, its three-dimensional copy will be readable for over thirty years, two or more times longer than other products in use today.  
         [0031]     The marker  10  may be mounted onto a concrete or other surface in the following manner. The surface may be a flat or plane surface, and may also be the curved or flat surface of a utility pole of concrete, wood or fiberglass. Referring to  FIG. 3 , a hole saw  20  having a diameter substantially equal to that of the marker  10  may be used to make a shallow circular groove into the surface on which the marker  10  is to be mounted. For centering purposes, and to accommodate a bolt for securing the marker  10  on the surface, the hole saw  20  has a drill  22  with a carbide bit  24 . Using a power tool, the hole saw  20  and carbide bit  24  can be used to drill a center hole, perhaps to a depth of 1.0 inch, in the center of a circular groove having a depth nominally in a range from 0.0625 to 0.125 inch into the concrete, asphalt or other surface where the marker  10  is to be mounted. The purpose of the circular groove is to accommodate the flange  12  on the marker  10 .  
         [0032]     Upon completion of the drilling process, dust and chips are blown or brushed out. An adhesive or epoxy is then applied to fill the drilled hole and the area inside the circular groove. The marker  10  is then centered over the circular groove, lining up flange  12  therewith, and pressed down. As a consequence, the leading edge  14  or the flange  12  will be below the surface of the concrete or asphalt and the marker  10  will be embedded in the surface, presenting a much lower tripping hazard than other mounting methods.  
         [0033]      FIG. 4  is a partly cross-sectional and partly perspective view of a marker  30  having a somewhat different design from marker  10 . The marker  30  has been installed in the manner described above. Flange  32  is disposed in circular groove  44 , and, as such, the leading edge  34  of the flange  32  is below the surface  40  of the concrete, asphalt or other material. An adhesive or epoxy  42  is used to hold the marker  30  to the surface  40 . Because the marker  30 , like marker  10  described above, has embossed areas which increase the surface area of the underside, the adhesive or epoxy  42  has increased area to bond both to the underside of the marker  30  and surface  40 . Also shown is the optional bolt  36  which is secured within hole  46  by adhesive or epoxy  42 .  
         [0034]      FIG. 5  is a perspective view of marker  10 , which lacks a bolt  36 , installed on a surface  40  of concrete, asphalt or the like. Little adhesive or epoxy  42  may be seen around the perimeter of the marker  10 . Because the flange  12  of marker  10  is within a circular groove  44  into surface  40 , an implement, such as a screw driver or penknife, cannot reach below leading edge  14  to pry the marker  10  away. When embedded into concrete or asphalt in this manner, a snow plow scraping the top surface thereof will not dislodge the marker  10  as its flange  12  is firmly mounted below the level of the surface  40 .  
         [0035]     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.