Road marker base with improved adherence and light transmission

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] The present invention relates generally to road markers and more specifically to a base for a road marker with improved retained light transmission and securement in a recess of the road.

[0003] Pavement road markers generally include a base and a light source or reflector on the base. The base is mounted in a recess in the road and held thereto, for example, by epoxy. The bases usually include a reflector support surface and a series of locators or buttons extending from the lateral edge thereof. The bottom surface of the locators engages the top surface of the roadway to position the reflector support surface at a given distance below the top surface of the roadway. The locators are an integral part of the base which is generally a cast of iron material. Such a road marker is illustrated in U.S. Pat. No. 5,454,664 to Siblik.

[0004] One of the problems experienced by all road markers is that they are damaged and/or ejected from the recess in the road surface by continual forces applied by snowplow blades or other snow removal equipment. Typically, the adhesive epoxy will secure the base to a recess in the road and forms a stronger bond with the base than it does with the road. Thus, they move as a unit and the bond between the epoxy and the road is broken. Once this bond is broken, further impact from snowplows or other snow removal devices will eject the road marker from the recess in the roadway.

[0005] It has also been noticed that there are times that the epoxy does not form a good bond with the base and therefore provides a gap which is increased when forces are applied from a plow or other sources.

[0006] Also, with the present design bases, water collects on the base around the reflector creating what is known in the industry as “ponding.” Once the evaporation process begins, any residue collects on all surfaces of the casting as well as the reflector. The residue that dries along the portions of the reflector reduces visibility or reflectivity and the functional performance of the unit. The natural “tire wiping” action from the vehicles does remove the upper portion of the residue, but cannot remove the lower portion of the residue from the reflective lens. This residue could represent up to 50% of the reflector surface.

[0007] The vast majority of snow plowable raised pavement markers are made of iron heat treated to withstand the impact and abrasion of the plows running over their surfaces. The heat treat process performed does not protect the surfaces of the casting from rusting. Reflectors are mounted in recessed areas to protect them from damage but still allowing visibility once installed. Immediately after installation, the complete outer surface of the casting begins to rust (oxidize).

[0008] Any rust between the casting and epoxy used to install the marker in the roadway will not allow the correct or necessary bond between the casting and the epoxy. Even after installation, any impact that would cause a “seal break” will allow the rust process to begin and further contaminate the security of the bond.

[0009] The moisture collects in the casting up to the actual road level. This moisture accelerates the rust process and once the evaporation process begins, the residue from the rust collects on all surfaces of the casting as well as the reflector. This is another source of the reduced reflectivity.

[0010] The present invention recognizes that one of the sources of both of these problems is rust or oxidation. A road marker of the present invention includes a metallic base for mounting on a road and a light transmitter mounted on the base to transmit light or reflect vehicle lights traveling on the road. An oxidation inhibiting coating is provided on the base. The base may be a cast heat treated metal for example iron or steel or may be aluminum for example.

[0011] The coating may be plated on the base. The coating may be zinc. The coating may also be between the reflector and the base.

[0012] A method of forming a road marker including a metallic base and a light transmitter, includes coating the metallic base with an oxidation inhibiting layer; and mounting the light transmitter on the base. The coating is performed before the mounting. The coating may be a plating.

[0013] These and other aspects of the present invention will become apparent from the following detailed description of the invention, when considered in conjunction with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]
FIG. 1 is a top plan view of a base of a bidirectional road marker.

[0015]
FIG. 2 is a full cross sectional view taken substantially along line II-II of FIG. 1 with a reflector shown in phantom.

[0016]
FIG. 3 is a side elevational view of the base of FIG. 1 in its installed position in a roadway.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] The present invention reduces the source of both of the problems by reducing the rusting of the base. All casting (for example Iron or Steel) or any other material (for example aluminum) that can oxidize or rust will be coated with a commercially available “plating” or metal treatment. As an example, a 0.00015″ thick Clear Zinc plating is applied. Other rust proof coatings may be used. Plating is preferred in that it will last longer. This process will enhance the performance of the entire assembly and reduce the problems. For non-snow plowable bases, any method of coating can be used since they are only subject to wear from the vehicle's tires.

[0018] Plating the raw casting, after heat treatment but before assembly (with the reflector), will prevent the rust problem during and after installation. Even a “seal break” condition will not allow the rust process to begin. In addition, the plating under the reflector pad will reduce the likelihood of premature separation between the “butyl” pad which secures the reflector to the base and the base coating.

[0019] Further, the plating on the top surfaces where the natural “ponding” of water takes place will significantly slow the inherent rust process and will only rust as the wear from tires or plow blades causes the plating to be removed or as long as the plating lasts. This, in turn, will have a beneficial effect on the performance of the reflector or light transmitter. The normal residue will not accumulate as fast or as much due to the areas not contacted by tires or plow blades will last as long as the plating can withstand the elements. With the reduced residue, the reflector lens will perform “like new” which will translate into a brighter/longer condition.

[0020] A base 16 for a road marker capable of carrying one or more light sources or reflectors is illustrated in the FIGS. 1-3. Base 16 is but an example of a snow plowable road marker and other road marks which would rust or oxidize could be used with the present invention. These could include non-snow plowable road markers. Whereas FIGS. 1-3 is a base designed for a bidirectional road marker, a base designed for a unidirectional road marker may also be used. The base includes a reflector support surface 18 surrounded by a moat 17. A pair of sloping vision ramps 20 extends there from in the direction of travel T. The vision ramps 20 terminate in a downwardly expending surface 22, edge 23 and an undercut surface 24.

[0021] The total surface of the base is coated with an oxidation inhibiting coating C. Because the thickness of the coating or the plating is so thin compared to the other dimensions of the marker it is not shown in FIGS. 1-3, but is represented by the legend C. As shown in FIG. 2, the coating C is also between the base 16 and the reflector 70.

[0022] Laterally flanking the reflector support surface 18 and the vision ramps 20 are side rail portions 26 of the base 16 having matching generally accurate upward surfaces 28 which are radiused downwardly at the opposite ends along the direction of travel and cresting adjacent the reflector support surface 18. The surfaces 28 of the rail 26 are flanked along their upward sides by angular downward and sloping side surfaces 30 which terminate at an edge 32.

[0023] The base 16 includes a plurality of protrusions 34 extending horizontally there from in opposite directions and transverse to the direction of travel T. The protrusions have a bottom surface 36 for engaging the top surface of a road adjacent a recess in the road. The bottom surface also defines the height of the reflector support surface 18 relative to the road top surface. FIG. 3 specifically shows a recess R having the base 16 therein with the bottom surface 36 of the protrusions 34 resting on the road surface S. The base 16 is held in the recess R by adhesives A.

[0024] The protrusions 34 are used only during the period of installation wherein the protrusions 34 set the height of the reflector support surface 18 relative to the road support surface S. Once the adhesive A has hardened, they serve little other purpose and generally have a negative affect during plowing. The ends of sloping surfaces 28 of the rails 26 and the edge 23 of the vision ramps 20 all terminate below the bottom or locating surface 36 of the protrusions 34 and consequently the road surface S. When properly installed, the adhesive A also covers these edges. Thus, the edges of the top surface do not offer easy targets for snowplow plates or other movable objects which would create undesirable forces breaking the seal between the base 16, the adhesive A and the recess R. Also, the ends of the rails 26 and the vision ramps 20 are below the road surfaces and are encased in the adhesive A and offer further resistance to movement along the direction of travel T.

[0025] To further increase the resistance of the base 16 to movement within the recess R, the bottom surface 52. The bottom surface 52 includes various vertical protuberances. The first are ribs 54 and the second are side webs 56.

[0026] Both vertical protuberances 54 and 56 offer resistance to movement of the base 16 in the recess R as well as to disperse the liquid adhesive up over the side surfaces 37 such that the edge 32 is completely encased by the adhesive. When properly designed, they eliminate the need for caulking after the adhesive is set because the adhesive did not appropriately spread past the edge 32 and onto surface 30.

[0027] Preferably, a reflector 70 with a center post of metal 68 is used, as illustrated in phantom in FIG. 2 on the support surface 18 extending up there from and transverse to direction of travel T. The wall 68 at least has the height of the reflector. This provides the protection as described in U.S. Pat. No. 4,454,664. A pad or strip of butyl mastic are applied to the bottom portions of the back wall of the bottom of the reflector 70. Such a mastic is indicated as 72 in phantom.

[0028] A method of forming a road marker including a metallic base 16 and a reflector 70, includes coating the metallic base 16 with an oxidation inhibiting layer C; and mounting the reflector 70 on the base 16. The coating C is performed before the mounting. The coating may be a plating.

[0029] As previously discussed, the water will collect on the face of the reflector 70, fill in the moat 17 and totally up the ramps 20. By providing the coating C on the casting, it does not reduce the amount of moisture being retained, but it significantly reduces the rust or oxidation residue which, when evaporated, coats the reflector surface 70. Also, the coating increases the adherence of the reflector 70 to support 18 of the base 16 and the base 16 to the adhesive A.

[0030] To illustrate the effectiveness of the present anti-oxidation coating, test results of prior art, non-coated road markers were compared against a test of coated road markers. Table 1 illustrates the results. The first three models in the column on the left are available from Hallen Products, Ltd. of Gurnee, Ill. Fifty markers each were installed on asphalt and concrete sections of Interstate Route 270 in Ohio. The resulting percentage of retained brightness is shown. The percentage of retained brightness was obtained by measuring the reflectivity of the markers at two periods in time and comparing the relative dirtiness. The ratio of the two dirtiness readings provide the percentage of retained brightness. The average is given at the bottom of the table. As indicated in the table, all of the readings were taken for 178 days, with the first reading being Sep. 15, 2000, and the second reading being on Mar. 16, 2001. Thus, a full winter period elapsed between the two dates in which the readings were taken.

[0031] The right side of the table shows two other models available from Hallen Products. They are aligned with their corresponding model from the previous experiment. Even though they have somewhat different product numbers, they use the same base and, thus, would have the same pooling and road wear. In each of the columns for asphalt and concrete, there are two readings provided. The averages on the left are for 20 markers, and the averages on the right are for 40 markers. The selection of the 20 markers represent the markers that are measured with the same instrument. The averages for the 40 markers are for all of the readings, even though they may have been taken by two different instruments. The averages are also shown for the coated markers. These were installed in Maryland. The concrete was on Interstate I-97, and the asphalt was on Maryland Route 100. The times of the various readings are indicated in notes B, C, D and E. With respect to note E, there was no meter reading available on one of the 40 markers and, therefore, the average represents 39 markers.

1TABLE 1% Retained Brightness% Retained Brightness (A)AsphaltConcreteModelAsphalt (50)Concrete (50)(20/40)(20/40)ModelH9602030H1010HP1525.96643M1W12.522.962.8 (B)/56.2 (B)51.3 (D)/48.5 (D)1W664Morthstar 419.624.090.4 (C)/82.4 (C)53.7 (D)/50.8 (E)H960HPAVERAGE:14.325.776.6/69.352.5/40.6Notes: (A) Sep. 15, 2000 to Mar. 12, 2001 (178 days) (B) Oct. 17, 2001 to Apr. 15, 2002 (189 days) (C) Nov. 13, 2001 to Apr. 15, 2002 (153 days) (D) Oct. 24, 2001 to Apr. 15, 2002 (182 days) (E) Oct. 24, 2001 to Apr. 15, 2002 (182 days); 39 markers

[0032] A review of the table will indicate that the coated road markers in concrete showed twice the retained reflectivity from that of the non-coated equivalent marker. This is true for the individual markers, as well as for the averages. Also, for the asphalt, the coated marker shows almost a 5 to 10 times improvement. Although the comparison may not be exact, in that they are different roads and the amount of moisture and traffic may be different for each of the time periods taken, the results still show a substantial increase in retained reflectivity, even if one took into account a substantial variation in traffic and weather conditions.

[0033] As used herein, a light transmitter is an element which reflects external light or may be a light source itself. The ability of the light source to transmit the light would also be subject to reduction due to dirt on its outer surface. Thus, the present invention would increase its transmission of light.

[0034] Although the present invention has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.

Road marker base with improved adherence and light transmission

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