Abstract:
A reflective surface marker comprising a pair of generally parallel lower legs, each leg having a first end; a pair of generally parallel upper legs, each leg having a first end; a flexible hinge resiliently connecting the first end of said lower leg to the first end of said upper leg; a reflective material connecting said upper legs; and a bladder for resiliently supporting the reflective material.

Description:
[0001]    This Application claims the benefit of U.S. Provisional Application Ser. No. 60/466,292 filed Apr. 29, 2003. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to light reflective and locational pavement markers for use in identifying the lines or boundaries of roadway surfaces. More specifically, the invention relates to an improved version of a highway lane delineator in the form of a flexible raised pavement marker that is made entirely from plastic and rubber. It also relates specifically to a flexible reflective pavement marker that is both easy to recycle and much less damaging to plow implements.  
         BACKGROUND OF THE INVENTION  
         [0003]    Current pavement markers are comprised of a steel frame having two parallel side rails designed to protect a reflector that is situated between the two side rails. These current pavement markers have several drawbacks. First, the steel side rails are designed to deflect the force of a plow blade, thus protecting the reflector. This constant striking and bouncing, however, causes undesirable and potentially costly wear and tear to the plow mechanism and to the plowing vehicle. It is also distracting to the plow operator who must endure the effect over many miles of interstate highway plowing. Secondly, current road repair and replacement techniques frequently involve grinding up large sections of roadway. The current steel markers need to be removed by hand before road resurfacing equipment can grind down the existing road surface. This process is often difficult and time-consuming due to the fact that the pavement markers are frequently bonded using high-strength epoxies. Additionally, steel is expensive to fabricate in comparison to injection molding, and expensive to ship in relation to the lightweight materials employed in the present invention. Lastly, steel reflectors can be dangerous missiles if inadvertently dislodged for any reason.  
           [0004]    In the experience of this inventor, there is an established and convenient way in which the markers are currently mounted. In general, standard size diamond cutting blades are used to cut two parallel side grooves in the pavement. A center groove is then cut between the side grooves. The device of the present invention is designed to use the same mounting hole as is currently used for steel markers, as this is an established and efficient way of mounting them, particularly in reinforced concrete interstate highways.  
           [0005]    The pavement marker of the present invention provides for a one-way reflector design, which is used for the majority of interstate markers. The marker uses the same size reflector that is mounted in the same relationship to the road surface as are steel markers. This insures the same reflectivity as is currently produced by steel markers, with the same reflector cleaning effect of tire action. Also, the low weight of plastic which is used to produce the marker of the present invention makes the unit safer if inadvertently dislodged and less expensive to ship. When grinding road surfaces, the pavement marker of the present invention can simply be ground up with the rest of the road surface without removing the unit from the roadway. It also may be possible to use reground tires for at least a portion of the rubber component of the marker of the present invention, thus helping to recycle this material.  
           [0006]    In the marker of the present invention, an articulating plastic-rubber assembly is attached to a retro-reflector, which enables the reflector to move slightly downwardly and out of the way of snowplow blades. The device is intended as an alternative to steel raised pavement markers and has numerous advantages. The two main benefits of the marker of this invention are the elimination of the bouncing of the plow blade and the low cost of manufacture associated with injection molding. The foregoing and other features and advantages of the device of the present invention will be apparent from the detailed description that follows. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a top, right side and rear perspective view of a pavement marker constructed in accordance with the present invention.  
         [0008]    [0008]FIG. 2 is a top, right side and rear perspective view of the marker shown in FIG. 1 as it would appear installed in the installation grooves cut into a road surface.  
         [0009]    [0009]FIG. 3A is a top plan view of the right leg assembly of the marker.  
         [0010]    [0010]FIG. 3B is a right side elevational view the right leg assembly of the marker.  
         [0011]    [0011]FIG. 3C is a rear elevational and cross-sectional view of the right leg assembly of the marker taken along line A-A of FIG. 3B.  
         [0012]    [0012]FIG. 3D is an enlarged detail view of the view shown in FIG. 3C.  
         [0013]    [0013]FIG. 4A is a top, left side and front perspective view of the right leg assembly of the marker shown in FIG. 3B.  
         [0014]    [0014]FIG. 4B is a top, right side and rear perspective view of the right leg assembly of the marker shown in FIG. 3B.  
         [0015]    [0015]FIG. 4C is an enlarged detail view of the front end of the right leg assembly illustrating the inside of the circular joint and showing the notch between the upper and lower leg.  
         [0016]    [0016]FIG. 4D is another enlarged view of the front end of the right leg assembly illustrating the outside of the circular joint and showing the notch between the upper and lower leg.  
         [0017]    [0017]FIG. 4E is an enlarged partial right elevational view of the front end of the right side leg assembly of the marker and showing the detail of the circular joint.  
         [0018]    [0018]FIG. 4F is a rear elevational and cross sectional view of the circular joint taken along line B-B of FIG. 4E.  
         [0019]    [0019]FIG. 4G is a front elevational and cross sectional view of the circular joint taken along line C-C of FIG. 4E.  
         [0020]    [0020]FIG. 5A is a top plan view of the pavement marker shown installed in a road.  
         [0021]    [0021]FIG. 5B is a right side elevational and cross sectional view of the pavement marker as installed in a road taken along line D-D of FIG. 5A.  
         [0022]    [0022]FIG. 6A is a top plan view of the pavement marker shown installed in a road.  
         [0023]    [0023]FIG. 6B is a right side elevational and cross sectional view of the pavement marker as installed in a road taken along line E-E of FIG. 6A.  
         [0024]    [0024]FIG. 7A is a top plan view of the pavement marker as installed in a road and showing a portion of a snowplow blade passing over the right leg assembly of the marker.  
         [0025]    [0025]FIG. 7B is a right side elevational and cross sectional view of the pavement marker and snowplow blade taken along line F-F of FIG. 7A.  
         [0026]    [0026]FIG. 8A is a top plan view of the pavement marker as installed in a road and showing a portion of a snowplow blade passing over the right leg assembly of the marker.  
         [0027]    [0027]FIG. 8B is a right side elevational and cross sectional view of the pavement marker and snowplow blade taken along line G-G of FIG. 8A.  
         [0028]    [0028]FIG. 9 is a top, front and right side perspective view of one embodiment of the pavement marker and showing a removable reflector. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]    Referring now to the drawings in detail, wherein like numbers refer to like numbered elements throughout, FIG. 1 illustrates a pavement surface marker, generally identified  2 , constructed in accordance with the present invention. In the preferred embodiment, the marker  2  is constructed primarily of a lightweight plastic material. As shown, a plastic reflector  1 , is attached to and suspended between two mirror-imaged upper leg components  3  of the marker  2 . Each of the upper leg components  3  is pivotally attached to a lower leg component  5 . On each side of the marker  2 , a rubber flange  7  which is part of the natural rubber component, is interposed between the upper leg component  3  and the lower leg component  5 . The flanges  7  prevent the attaching material, an epoxy adhesive, from oozing onto the upper leg components  3 . The flanges  7  serve an additional purpose, which is to hold the marker  2  in place during installation, thereby resisting the tendency of the lightweight plastic device to float out of the groove  11  in which the lower leg components  5  are placed on top of the liquid epoxy. A separate rubber bladder  9  is bonded to the bottom of the reflector  1  with adhesive which prevents the formation of ice under the reflector  1 . The bladder  9  also works to keep dirt and other road debris from getting under the reflector  1  and preventing it from flexing below ground level.  
         [0030]    [0030]FIG. 2 shows the marker  2  as it would appear installed in a road surface  10 . Existing diamond saw machines with ‘standard’ 18 and 20-inch diameter blades are used to produce two parallel and longitudinally extending side grooves  11  and a shallower center groove  13  that extends between the side grooves  11 . Four leveling tabs, one on each of the lower legs  25  and one on each of the upper legs  27 , are used to visually insure that the marker  2  is set at the correct depth during installation.  
         [0031]    [0031]FIGS. 3A and 3B show in greater detail the right leg assembly  3 ,  5 , which is an exact mirror image of the opposite left leg assembly. FIGS. 3C and 3D show the rubber component  14 , which provides the flanges,  7  and which is molded into the two plastic lower leg components  5  and held in place by thermal bonding and grooves  15  which run the length of the plastic lower leg components  5 . The rubber component  14  forms a protective void, keeping water and debris from entering into the area that the upper legs  3  flex into. In the preferred embodiment, ribbing spaces  17  are formed in the lower legs  5  and serve to provide compressive strength and also a large undercut volume for the epoxy to flow into. This strong mechanical bond is a substantial improvement in retention safety versus the purely chemical bond on common steel markers.  
         [0032]    [0032]FIGS. 4F and 4G illustrate the novel way that the upper legs  3  are joined with the lower legs  5 . Equal-sized notches  19  are molded into each of connections between an upper leg  3  and a lower leg  5  which surrounds a centralized, circular, common section  21 . During manufacture, this entire area, including the circular common section  21  becomes filled with rubber and, in effect, forms a torsion spring, holding the reflector  1  in its normal position. When depressed by a tire or snowplow blade  47 , the natural position of the rubber forces the two leg components  3  back to the normal position. This occurs due to the rubber filling the notches  19  and the circular common section  21 . When the pavement marker  2  is depressed, the rubber cores  23  act as a resilient torsional spring, applying pressure via the notches  19  to return the marker  2  to its raised position. There are positive mechanical stops in both positions resulting from the molded geometry of the plastic parts.  
         [0033]    The perspective views of FIGS. 4A and 4B show grooves  29  that are molded into both plastic parts  5  for improving the bond between the rubber and the two plastic parts  5  in each leg assembly. The post  31  also serves a dual purpose as a stress reliever for the reflector  1 , resisting unequal forces between the two upper leg components  3 . This could occur, for example, when one upper leg component  3  is depressed by a tire or plow blade  47  and the other upper leg component  3  is not. The post  31  is also used as a fill point for the injection of the special plastic material needed to resist the severe impact of plow blades. A pair of top tabs  33  together with a bottom tab  35 , act in conjunction with the post  31  to hold the reflector  1  in place.  
         [0034]    [0034]FIGS. 5A through 8B show the normal configuration of the marker  2  compared to its position when struck by a plow blade. For example, FIG. 5B shows the marker  2  in its normal position and also shows the road  10  and the epoxy adhesive  37 , which has flowed between the ribs  17  in the lower leg components  5 . The protected void  41  is evident as is the mechanically reinforced rubber bond  43  across the top of the void. FIG. 6B shows the marker  2  in its normal position and shows the rubber bladder  9  and its associated void  45  which serve to prevent ice and debris from collecting under the reflector  1 . FIGS. 7A and 7B show a snowplow blade  47  striking and depressing the upper leg components  3 . This movement pivots on the center of the radius  49  thereby causing the two plastic parts  3 , 5  to meet along a shared radius  51 . The rubber segment  43  between the upper legs  3  and the lower legs  5  stretches to keep the seal intact. The air inside the void  41  becomes pressurized momentarily. In the case of stopped traffic, where the marker  2  may become depressed for many minutes, there is enough of a gap between the normal position of the marker  2  and the sidewalls of the cut  11 ,  13  in the road  10  to allow the rubber to controllably expand without compromising the seal. FIGS. 8A and 8B show the position of the reflector  1  and air bladder  9  when a plow blade  47  strikes the marker  40 . The normal position of the upper leg components  3  and reflector  1  are show as dotted lines. The pivot point is shown at the center of the dotted circle  53 .  
         [0035]    The present invention, in one embodiment, provides for an easily removable and replaceable reflector  1 . See FIG. 9. The removable reflector is mounted in bracket  55 , bracket  57  and is reinforced by a reinforcing bar  59 . Therefore, in areas of high roadway use where the potential for damaging reflectors exists, the reflector  1  can be replaced without replacing the entire unit. Additionally, areas in which it snows frequently use salt and other corrosives, which may damage the reflective surface, also show a need for a removable and replaceable reflector  1 .  
         [0036]    One possible manner of constructing the marker  2  of the present invention is to use an impact resistant plastic material to injection mold the upper leg components  3 . This material has a substantial long glass fiber content yet can replicate fine detail. When the material has cooled sufficiently, a coating of carbon-filled natural rubber is molded onto it, thereby creating half of the rubber seal between the two plastic parts  3 ,  5 . The bottom leg components  5  are molded separately of a less impact resistant plastic than the upper leg components  3 ,  4  and can be added to the mold containing the upper leg component  3  in a two shot molding process. The remainder of the rubber is molded to the assembly, creating the elastic pivot  21  and the side flanges  7  as well as sealing the leg assembly. The center air bladder  9  is produced from two molded halves that have mating features that facilitate the adhesive or thermal bonding of the two halves.