Abstract:
A road marker and method of manufacturing a road marker having a base with a large surface area. The base is molded around a potted road reflector to completely seal the bottom and encapsulate the ends of the reflective member. The reflective member has end extensions with notches formed to interlock with the base member.

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 08/948,948, filed Oct. 10, 1997, now U.S. Pat. No. 6,200,064 which takes priority from Provisional Application No. 60/028,302, filed Oct. 11, 1996. 
    
    
     FIELD OF THE INVENTION 
     This application relates to retro-reflective road markers for installation on the pavement of a road. 
     BACKGROUND OF THE INVENTION 
     Road markers having retro-reflective lenses are used on road surfaces to delineate lanes at night. The road markers reflect light from the headlights of an automobile at night to indicate where the lanes of a road are positioned. The markers typically have a trapezoidal cross-section with a rectangular bottom. These markers are approximately two inches wide by four inches long and three-quarters of an inch high. The markers are mounted directly to the road with suitable materials such as bituminous or epoxy. 
     The markers typically include a molded plastic shell which has cube corner reflective surfaces. These surfaces are formed on the inside of the shell and plated with metal, preferably aluminum. The shells are then filled with a potting material, such as a mixture of epoxy, to provide strength. The potting material provides the marker with strength to withstand the weight of large vehicles such as trucks. 
     Recently, it has been found that the reflectivity of potted reflectors is decreased over time by transmigration of asphalt chemical tar from the road surface and of the bituminous material used to affix the markers to the road to the metallic coating on the inside of the shell. Thus, it is desirable to provide a marker which is economical, strong and which will resist transmigration. 
     SUMMARY OF THE INVENTION 
     The invention relates to a potted road marker and method for making the road marker. The road marker includes a reflective member and a base member which is formed about the end portions and a bottom to encapsulate portions of the reflective member. The reflective member includes a shell having a top and two sides which extend between a pair of ends. At least one of the sides is formed with cube corners which are metallized. The top, sides and ends define a cavity which is filled with a potting material such as epoxy. Each end of the marker has an extended portion which extends longitudinally outwardly. The base member has a lower platform portion having two projections which extend upwardly from the top surface of the base. The projections are spaced apart to receive the reflective member thus between. The projections are wider and slightly higher than the reflective member. The end projections have a curved surface extending from the top to the base so that the projections protect the ends of the reflector. The base is molded about the previously formed reflective member so that the ends of the reflective member are encapsulated in the projections of the base member. In this way, each reflector is securely held to the base and permanently mounted to the base member. Additionally, the base of the reflector member is encapsulated in the base member to prevent transmigration of bituminous or tar chemical into the reflective member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more fully understood by reference to the following detailed description when read in conjunction with the accompanying drawings in which the reference characters refer to like parts throughout the several views and in which: 
     FIG. 1 is a perspective view showing a road marker according to the invention mounted to a road surface; 
     FIG. 2 is a cross-sectional side view of a road marker in accordance with the invention taken along lines  2 — 2  of FIG. 1; 
     FIG. 3 is a bottom view of the road marker in accordance with the invention; 
     FIG. 4 is a cross-sectional side view of a portion of molds forming the base member about the reflective member; 
     FIG. 5 is a cross-sectional view of a reflective member in accordance with the invention; 
     FIG. 6 is a partial cross-sectional side view of the reflective member taken along lines  6 — 6  of FIG. 5; 
     FIG. 7 is a partial cross-sectional side view of the reflective member taken along lines  7 — 7  of FIG. 5; 
     FIG. 8 is a perspective view of a portion of the reflective member showing the ribs and blade for engaging the fill material; 
     FIG. 9 is a perspective end view of the reflective member before it is encapsulated by the base member; and 
     FIG. 10 is an alternative embodiment of a preferred embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A road marker in accordance with the invention is shown mounted to a road surface in FIG.  1 . As best shown in FIGS. 1 and 2, the road marker  10  includes a reflector member  12  and a base member  14 . The road marker  10  is mounted to the road surface  16  with a suitable mounting compound, such as bituminous  17  or hot melt material. The embodiment discussed herein is of the type suitable for use on asphalt surfaces which soften with heat, such as disclosed in U.S. Pat. No. 6,200,064; however, the invention is not limited to this embodiment and may be used with any type product road marker. 
     As shown in FIGS. 1,  5 ,  6 , and  9 , the reflector member  12  includes a shell  18  having two angled sides  20  and a top surface  22  which extends between a pair of trapezoidally shaped ends  24 . The shell  18  is formed of a translucent plastic material and may be molded in a single piece or in two halves which are joined together by gluing or ultrasonic welding. The sides  20  have a retro-reflective portion  26  formed in a conventional manner by molding cube corners on the inner surface. It should be noted that the reflector member  12  shown has the retro-reflective portion  26  on each side  20 , however, in some cases only one side  20  has the reflective portion  26 . 
     As shown in FIGS. 5-7, a brow  25  or raised lip extends between the ends  24  above the sides  20 . The brow  25  protects the sides  20  from abrasion when a tire passes over the reflection marker  12 . The brow  25  is particularly useful in preventing the removal of protective coatings as disclosed in U.S. Pat. No. 5,098,217. Two pairs of arms  21  are formed to extend outwardly from the top surface  22  to support the reflective marker during the filling of the potting material as discussed more fully below. 
     As shown in FIG. 6, the reflector member has a lower portion  23  about which is molded the base member  14 . The lower portion has an edge surface  27  which is angled a minimum of 10° from vertical to extend from the side surface  20  away from the center of the marker to a bottom edge  29 . The angled edge surface  27  interlocks with the material of the base member  14  to lock the reflector member  12  to the base member  14 . 
     As best shown in FIGS. 5 and 9, each end  24  of the shell  18  has an extended portion  30  with a trapezoidal wall  32 . Each extended portion  30  is formed for encapsulated in the base member  14 . To further this purpose, a notch  34  is formed between the wall  32  and end  24 . The notch  34  has a bottom surface  36  spaced apart and parallel with the side  20  and a top surface  22 . The bottom surface  36  extends approximately {fraction (3/16)}″ between the end  24  and wall  32 . 
     As shown in FIGS. 5-8, a longitudinal flange  35  extends from beneath the brow  25  adjacent each side  20  of the reflector member  12 . The flanges  35  extend to a point and are angled inwardly towards each other to engage potting material  28  in the cavity. A plurality of ribs  37  are spaced apart to extend transversely below the top into the cavity. Each of the ribs  37  is pointed and extends below each flange to provide strength to the top  22  and engage the potting material  28   
     The reflector member  12  may be formed as one piece, as shown in FIG. 1, or in two halves, such as shown in FIG.  5 . The two halves are glued together, as known in the art. An inner surface of the retro-reflective portion  26  is metallized by vacuum plating. The reflector member  12  is inverted and filled with the potting material  28 . The potting material  28  is typically a filled epoxy urethane or other suitable material. The potting material  28  flows into the cavity and surrounds the flanges  35  and ribs  37 . After curing, the potting material  28  forms a rigid mass engaging the flanges  35  and ribs  37  to provide strength to the reflector member  12  to withstand the pressure of tires of vehicles passing over the road marker  10 . 
     As shown in FIGS. 1,  2  and  3 , the base member  14  has a disc-like lower portion  38  and a pair of diametrically opposed projections  40  extending from the lower portion  38 . As shown in FIG. 6, the lower portion has a stepped peripheral edge  46  extending from a bottom surface  44 . The edge  46  is stepped to permit the bituminous  17  to ooze over the top of the bottom step  43  to improve the adherence of the marker to the road surface. The step  43  has a height of approximately {fraction (1/32)}″ and extends approximately 0.030 inches in a horizontal direction. The edge  46  has opposed edge portions  45  which extend parallel to the sides of the reflector member. The lower portion  38  at the base member is approximately {fraction (3/16)} inch thick and has a diameter of approximately 5-½ inches. Thus, the surface area of the bottom is more than twice the surface area of a conventional 2″×4″ reflector member. The base member  14  may be molded of any suitable material such as ABS. 
     As shown in FIG. 3, the bottom surface  44  has a plurality of circular perforations  48  formed in a plurality of radially extending lines. The perforations  48  and two pairs of elongated ribs  49  are formed to receive the glue or epoxy for improving adherence of the marker to the road. The elongated ribs are formed to extend parallel with the sides  20  of the road marker so as to prevent dislodgement of the road marker when the tire of a vehicle contacts and passes over the road marker  10 . 
     As shown in FIG. 2, the projections  40  have inner walls  50  which are spaced apart to receive the ends  24  of the reflector therebetween with the notch  34  of the end extension of the reflector member captured by the projection  40  which extends into the notch  34 . Each projection  40  has the shape of a quarter sector of an elongated sphere. The projection is set inwardly from the angled edge  46  and has a curved surface  54  which extends upwardly and inwardly from the top surface  42  to the reflector member  12 . Each projection has a top portion  56  which is generally flat and slightly above the top surface  22  of the reflector. The projections  40  act to protect the ends  24  of the reflector member from shock and wear as a tire of a vehicle passes over the reflector member. The projections  40  are contoured to facilitate a smooth passage of the tires. Recesses  58  extend from the bottom surface between the walls of the projector from the bottom surface. 
     In the preferred embodiment, the base member  14  is formed of an ABS material. The ABS material has particularly good shock absorbing characteristics. Other moldable materials such as acrylic may be used. 
     An alternative preferred embodiment of the invention is shown in FIG. 10. A road marker  60  has a rectangular base member  62 . The rectangular base member  62  has a length which extends at least 1″ greater than the length of the reflector member  12  and a width “w” which is greater than the width of the shell  18  to at least double the surface area of a bottom surface of the base member compared to the area of the bottom of the reflector member. 
     The road markers  10  and  60  are formed first by molding the shell  18  of the reflective member in a conventional manner. The shell may be formed in a single piece or two complementary pieces which are glued together on their longitudinal edges to form a completed shell  18  with an inner cavity as disclosed above. The shell has at least one retro-reflective portion  26  with “cube corners” integrally molded on the inner surface of the shell. The “cube corners” are metallized by vacuum forming as is known in the art. The marker  10  is then inverted to rest on the arms  23 . The cavity is then filled with a potting material, such as epoxy. After the potting material has set, the reflector member is placed within a mold  66  as shown in FIG.  4 . The mold  66  has cavities  68  for forming the base member  14  around the reflector member  12 . The cavities  68  of the mold  66  are then filled with suitable material, such as epoxy or urethane, and allowed to cure. The arms  21  are then snapped off. 
     Thus is provided a road marker having a reflective member having a bottom which is sealed against transmigration. The base member has projections which protect the ends of the reflector as well as lock the reflector to the base member. The bottom surface is enlarged with respect to conventional reflectors to prevent depression of the marker into softened road surfaces. 
     Having described my invention, however, many other modifications thereto may be apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.