Process of manufacturing one piece reflective pavement marker and delineator

Information

  • Patent Grant
  • 6698972
  • Patent Number
    6,698,972
  • Date Filed
    Tuesday, August 8, 2000
    23 years ago
  • Date Issued
    Tuesday, March 2, 2004
    20 years ago
  • Inventors
  • Examiners
    • Will; Thomas B.
    • Addie; Raymond
Abstract
A Method of manufacturing a hollow, one piece, reflective pavement marker, including at least one retro-reflective face. The method includes molding a plurality of cube-corner reflective elements within a plurality of cells, defined by plural load carrying and partitioning walls. The pavement marker includes a profiled lower surface to improve agglutination to a roadway. The pavement marker can be made from high impact and abrasion resistant thermoplastics.
Description




BACKGROUND OF INVENTION




1. Field of Invention




This invention relates to the process of forming roadway markers that are used for traffic lane delineation, in particular, to markers with enhanced reflectivity and abrasion resistant.




2. Related Art




Roadway markers are adhered to pavements along centerlines, edge lines, lane dividers or guardrail delineators. Other roadway markers are used as temporary lane dividers in temporary constructions, detours or prior to permanent marking of newly paved roadways. Since 1965, the most commonly used retroreflective roadway markers are based on Heenan U.S. Pat. No. 3,332,327, Balint U.S. Pat. No. 3,409,344, or Edouart U.S. Pat. No. 4,991,994. Typically, this type of markers are produced in a process consisting of four or five steps: Firstly, injection molding of a thermoplastic shell, either integrally molded with the reflective face, or the reflective faces welded on a corresponding open recesses within the shell. The reflective face, having about 350 or more cube corner reflective elements on each reflective face of the shell. Secondly, either the reflective faces within a shell or the entire inside surface of the shell coated with a reflective metallic sealer by a process known as vacuum metalizing. This metallic sealer needed to seal the cube corner reflective elements so they retain part of their retroreflectivness prior to the next step of filling the shell with a thermosetting resinous material, such as epoxy or polyurethane.




This resinous filler material encapsulate the metalized cube corner reflective elements and give the marker the structural body. Finally, a layer of relatively course sand or glass beads dispersed over the top surface of the filler material prior to solidification of the filler material. This top surface will be the marker's base. Part of the sand particles will remain partially protruding above this planar surface of the marker base, thereby increase the adhesive welding parameter of the base surface. The protruded sand will improve adhesion to substrate, regardless of the type of adhesive used. This type of markers worked well for six or seven months, however, due to poor abrasion and impact resistant of the thermoplastic shell, over 60% of the reflectivity lost thereafter. Also, incompatibility of the shell material to the resinous filler material causes pealing of the reflective face or the shell, thereby losing retroreflectivity. Several attempt were made to improve abrasion resistant of the reflective face. One was the use of thin layer of untempered glass as disclosed in U.S. Pat. No. 4,340,319, another attempt was the use of polymeric coating of the reflective face, as disclosed in U.S. Pat. No. 4,753,548 to (Forrer). These abrasion resistant coating proving to be expensive and tend to reduce retro reflectivity. Other major development in the pavement marker art has been made, this was achieved by eliminate the use of the metalized sealer for the cube corner reflective elements. By dividing the inside surface of the reflective face into reflective cells, each cell will have several cube corner reflective elements, the cells isolated from each other by partition and load carrying walls. The reflective faces welded to corresponding recesses within a hollowed body.




This method is disclosed in U.S. Pat. Nos. 4,227,772 (Heenan); 4,232,979; and 4,340,319 (Johnson et al); U.S. Pat. No. 4,498,733 (Flanagan). These markers proved to be superior in reflectivity, however, lack of structural strength and poor adhesion cause short life cycle for this type of markers.




This applicant successfully developed two multi-cell reflective roadway markers. One roadway marker utilizes raised rhombic shaped abrasion reducing and load transferring raised ridges, said ridges intercede abrasion elements and impact load. The shell filled with epoxy, hence, the marker body having a base with large wetting parameter for shear and flexural strength , as disclosed in U.S. Pat. No. 4,726,706. The second roadway marker of this applicant, U.S. Pat. No. 5,927,897 developed a mean to increase the abrasion resistant of the reflective face by coating the reflective face with diamond-like film and by having holding pins extending from the partition walls into the body, the holding pins sealed by the filler material; this works very effectively. The entire above reflective pavement markers are incorporated herein by reference in their entireties. The present goal of Applicant is to have a durable roadway marker with high reflectance, abrasion resistant, low cost, marker base area with good welding parameter and one-step process to manufacture said reflective pavement marker.




SUMMARY OF THE INVENTION




This invention provide a novel process of forming one piece raised roadway marker or delineator that comprises a monolithically injected Body integrally with one or two reflective faces and a base having large adhesive welding parameter for better adhesion to the pavement and higher resistance to flexural stresses.




The primary objective of this invention is to provide one steps process for making reflective pavement markers or delineator while retaining maximum reflectivity and structural strength. Another objective of this invention is to provide a raised roadway marker made of high impact and abrasion resistant material and high quality reflective index.




The present invention further provide a method of making one piece raised roadway marker of any desirable shape and configuration, such as, a marker with truncated body or one piece delineator with two vertically positioned reflective faces, with means to include cube corner reflective elements on the interior of said faces, and having grooved planar base surface.




In accordance with still further aspect of this invention, the marker can be made for one or two way traffic usage; having integrally built-in reflective faces provides durability and cost effectiveness. Also two multi colored parts can be welded together to form multi colored reflective pavement marker.











BRIEF DESCRIPTION OF THE DRAWINGS




The advantages and unique features of this invention will be better understood by reference to the drawings. These drawings are schematics, no scale used. In the drawings:





FIG. 1

is an isometric view of one of the preferred one-piece pavement marker of the invention;





FIG. 2

is a plan view of the pavement marker illustrated in

FIG. 1

;





FIG. 3

is another isometric view of pavement marker in

FIG. 1

showing the base portion with grooved surface and the end opening for the hollow recesses;





FIG. 4

is a cross section view taken along the line


4





4


in

FIG. 2

;





FIG. 5

is an isometric view of a thin plate that can be used to seal the ends of hollow recesses;





FIG. 6

is a section view taken along the line


6





6


in

FIG. 4

showing partly grooved surfaces of a hollow recess;





FIG. 7

is an isometric view of yet another embodiment of one-piece marker of the invention;





FIG. 8

is a plan view of the marker in

FIG. 7

;





FIG. 9

is a cross section view taken along the line


13





13


in

FIG. 8

;





FIG. 10

is isometric view of the marker in

FIG. 7

showing the base surface and the back portion;





FIG. 11

is an isometric view of a sealing plate for the base of marker in

FIG. 7

;





FIG. 12

is an isometric view of two welded markers of

FIG. 7

;





FIG. 13

is a plan view of the marker in

FIG. 12

;





FIG. 14

is a cross section view taken along the line


18





18


in FIG.


12


.





FIG. 15

(FIG. Prior Art 15) is an isometric view of conventional slurry seal delineator.





FIG. 16

(FIG. Prior Art 16) is schematic view of a temporary pavement marker.





FIG. 17

is an isometric view of preferred delineator made in accordance to the invention.





FIG. 17



b


is isometric view of delineator of

FIG. 17

before sonically welding the two sides.





FIG. 18

is an isometric view of barrier-delineator manufactured accordance to the invention.





FIG. 19

is isometric view of another barrier-delineator based on the present invention.





FIG. 20

is isometric view of a dual use delineator-temporary marker as per this invention.





FIG. 21

is another isometric view of marker in

FIG. 20

showing the base surface.





FIG. 22

is an elevation view of the delineator of

FIG. 20

showing both top and lower body.





FIG. 23

is an elevation view of delineator of

FIG. 20

without the top portion.





FIG. 24

is an isometric view of one side of delineator of

FIG. 20

, showing the backside.




This is a continuation in part of Ser. No. 09/385,091, filed Aug. 30, 1999











DESCRIPTION OF THE PREFERRED EMBODIMENTS




Enhanced reflectivity, durability, cost effectiveness and simplified production method can be achieved by eliminating major steps or processes used in previous arts for manufacturing reflective pavement markers. This invention is satisfying the above conditions.




This invention eliminate the process of metalizing the reflective face, eliminate the step of welding a backing sheet or a lens mounting sheet to the reflective face; eliminate filling the marker body (shell) with inert filled or fiber reinforced resinous material or welding a unitarily molded block with flattened base to a shell; eliminate a lens mounting structure and a base layer added to marker body. This invention simply developed a process of making a monolithic reflective pavement marker in one-step process, this process comprises a mold that provide the means to form: the structural body, the cube corner reflective elements as well as a hollow cavity means that allow integrally forming of said cube corner reflective elements.




Referring to

FIGS. 1 through 6

represent one of the preferred embodiment of a durable one-piece reflective pavement marker designated by the number


200


, that is formed utilizing the process of the present invention, which comprises means to integrally cast marker


200


including at least one reflective face


212


.




Marker


200


has a top portion


214


, two arcuate sides


216


, two inclined planar faces


218


and


212


that are facing opposing traffics, with at least one face (


212


) is provided with means to form cube corner reflective elements


230




c


on a designated cell like interior surfaces


230


of said face


212


. Marker


200


also have textured and grooved planar base surface


220


with integrally extended base portion


220




a


for added adhesion area.




The inclined planar reflective face


212


integrally has the interior cell like surfaces


230


defined by the hollow cavity means


300


, which allow the integrally formed cube corner reflective elements


230




c


, to remain freely open within air gaps provided by said hollow cavity means


300


.




Reflective cells


230


can be of any desired shape or size. Various body shapes, reflective cells and cube-corner reflective element designs can be formed utilizing the method of the present invention. The following U.S. Patents provide suitable exterior body shape, cell and or cube corner element designs, therefore, all of the following arts are incorporated as reference in their entireties: U.S. Pat. Nos. 4,726,706 and 5,927,897 to Attar.




The outside surfaces of interior cells


230


are integral part of planar reflective face


212


. The interior cells


230


are positioned on designated cell like areas within inside surface of the reflective face


212


, and defined by hollow cavity means


300


, which provide the ejection means for injection molding of said multiple of protruding cube corner reflective elements


230




c


. The reflective elements


230




c


within an interior cell


230


are isolated from adjacent cells by integrally formed load carrying interior walls


310


, which are tapered outwardly, thereby defining the hollow cavity means


300


. Hollow cavity means


300


are directly beneath the interior of each cell


230


. Each hollow cavity


300


is formed corresponding to the size and shape of the interior cell like surfaces


230


with the protruding cube corner reflective elements


230




c


. Hollow cavities


300


are integrally positioned with their centerlines


500


forming angle (φ) of about 80 to 100 degrees with respect to the outside planar surface of reflective face


212


, thereby allowing uninterrupted injection molding process, hence providing the means for integrally forming the cube corner reflective elements. The load carrying interior walls


310


are tapered forming an angle (A) equal or less than 5 degrees with respect to each centerline


500


. Hollow cavities


300




a


are used when the desired marker is to have only one side with reflective face, as shown in marker


200


. Hollow cavities


300




a


can provide the means to form cube corner reflective elements on the inside cell like surfaces of the top portion


214


.




Both hollow cavities


300


and


300




a


will be tapered outwardly and open through the textured and grooved planar base surface


220


thereby forming air gaps beneath each individual interior cell


230


. Hollow cavities


300


and


300




a


can have some of the load carrying interior walls


310


and the interior surface of top portion


214


formed with textures or arcuate grooves


310




a


for added reflectivity, surface opaqueness, enhancing daytime reflectivity and improving the structural strength of the marker.




Marker


200


is made in one-step injection molding process, either in one stage or two-stage injection from a high impact resistance polymeric material, either in one color or two-color injection molding process.




Thermoplastic such as high impact resistance acrylic, polycarbonate or any other high impact resistance polymers are suitable to be used in this process. Reflective face


212


can have either three raw, two raw or one raw of reflective cells


230


, depending on the desired size, shape or height of marker


200


and the reflective cells


230


being used in this process.




For applications in sunny and hot environment, where bituminous hot-melt adhesive may be used, to agglutinate any marker to the roadway, the low melting point of such adhesive material may lead to adhesive failure known as cookie cutter effect, where a marker agglutinated to the pavement, may be forced by traffic impact load to move away from it's intended location on the roadway.




The science of material welding teach us that one of the primary variables to good adhesion of two surfaces is the total surface area to be wetted by the adhesive (welding) material, this area can be called the welding parameter, therefore, we can improve adhesion of marker


200


to a substrate, perhaps more effectively than the previous arts. This improvement in welding parameter can be achieved by using one of various arcuate shaped recesses within the base surface, each having discontinuous length. The grooves are perpendicular to traffic direction. Each groove can have length of about an inch or less and textured surface, preferably by sand blasting the corresponding part of the tooling.




The width or depth of such grooves should be less than 0.10 inch in-depth, by using short and discontinuous grooves, each near an inch in length with textured surface. In addition, planar base surface


220


can have an integrally extended portion


220




a


, which extends beyond the periphery of marker body for added adhesive grip.




Yet another mean to improve the adhesive welding parameter of the grooved planar base surface


220


is by capping the open ends of hollow cavities


300


and


300




a


by a corresponding shaped plate


185


with textured and grooved surface. Plate


185


can be used to plug a designated recessed area that can be provided within the base surface


220


, such recessed area will include all the openings of the hollow cavities


300


and


300




a


, thereby allowing sonic welding of said plate


185


to said recessed area of the base


220


.




In other applications where the desired marker to have two reflective faces with one or two colors, shorter body depth, lower height or maximum welding parameter at the marker base area. In this case, embodiments such as marker


10


and


10




a


can be formed in accordance to the method of the present invention.

FIGS. 7 through 11

illustrate marker


10


comprises of two integrally formed near identical shaped marker


10




a


, welded or glued together. Marker


10


can have either transparent or partially pigmented body.




Each marker


10




a


integrally comprises an inclined planar reflective face


110


, a top portion


121


, two arcuate sides


125


, a planar rectangular base surface


150


with textured discontinuous grooves, said base surface


150


can have an integrally extended base portion


130


which extends beyond the periphery of the top portion of marker body, and back portion


160


forming perpendicular angle with respect to the planar base surface


150


, said back portion


160


includes beaded surface and hollow cavities


165


. Various bead shapes or edges can be incorporated on the back portions


160


, thereby fusing said back portions to each other during sonic welding.




The planar reflective face


110


integrally has interior cell like surfaces


115


with means to integrally form multiple of cube corner reflective elements


115




c


on said interior cell surfaces


115


.




The interior cells


115


are open within air gaps provided by the hollow cavity means


155


, such openings are through the base surface


150


. The centerline of each hollow cavity


155


forms an angle (α) of about 80 to 100 degrees with respect to the outside surface of reflective face


110


. Each hollow cavity


155


separated from each other by an outwardly tapered partition and load carrying walls


155




a.






It can be shown that marker


10


can have any commonly used shape or size and the reflective face can have either one raw or multiple raw of reflective cells, each cell having either hexagonal, rectangular, rhombic or circular shape or a marker with round base and spherical surface. When additional welding parameter (area) is needed for the base surface


150


, the entire open ends of hollow cavities


155


can be capped by correspondingly shaped plate


180


, as in

FIG. 11

, which can be welded onto a corresponding size and shaped recessed area that can be provided within the base surface


150


. Marker


10


can be formed by means of welding the backsides


160


of two identical markers


10




a


. Two markers


10




a


are injection molded with thin wedge connection


166


. Wedge


166


can be tore apart so that, two markers


10




a


with contrasted colors can be welded at the back side


160


, forming marker


10


.




An alternative forming means can form each part


10




a


having a transparent segment, only within the reflective face


110


region, and the remaining segment of part


10




a


to be opaque.




Marker


10


is manufactured by means of an injection molding process, integrally including the two parts


10




a


, and forms the two parts with one color or two color segments.




Various embodiments according to the process of this invention can have improved abrasion resistant body. Preferably by coating the marker reflective face or the entire outside surface with either silicon dioxide (SIO2) film, or with diamond-like carbon film, as per referenced U.S. Pat. No. 5,927,897 to Attar. The process of the present invention can also be utilized to make other roadway markers, such as barrier delineators as well as temporary markers and mini marker for insertion into metal-based markers, such as used in snowy regions.





FIG. 15

(Prior Art 15) illustrates a schematic view of a typical L shaped delineator. This delineator made having either extruded or injection molded body


1


, and two reflective strips


2


attachments, each with multiple cube corner reflective elements, said strips


2


adhered onto the top part of said body.





FIG. 16

(Prior Art 16) illustrates another delineator or temporary marker. This type of temporary marker is usually made of two parts, a body with multiple of hollow cavities


3


, and at least one reflective plate attachment


4


.




The process of the present invention can integrally form the entire delineator or temporary roadway marker's structural body including the cube corner reflective elements by means of one single injection molding cycle. Such delineator or temporary roadway marker made of one type or two types of high impact and tear resistant thermoplastics. At least the reflective face portion integrally made of optically clear thermoplastic, including the cube corner reflective elements.




The illustrated embodiments in

FIGS. 17 through 25

exemplify few delineators and temporary markers that can be manufactured according to the process of present invention.





FIGS. 17 and 17



b


show one of the preferred embodiments of a delineator


10


. Delineator


10


is manufactured using means in accordance to the present invention.

FIG. 17



b


in particular shows the two sides


10




a


and


10




b


of delineator


10


, within the proximity of their position while being ejected during the injection molding process of delineator


10


. Each side


10




a


comprises a planar base portion


25




a


with grooves and a vertically positioned reflective face portion


20




a


. The base portion


25




a


is near perpendicular to face portion


20




a.






Face portion


20




a


is having two distinct sides, an interior side and exterior side. Both sides of face portion


20




a


are integrally partitioned into multiple of cell like shapes


22




a


. Cells


22




a


having planar surfaces on the exterior side, said planar exterior surfaces separated from each other by raised load carrying partitions walls


23




a


. Cells


22




a


have interior surfaces with means for including and integrally forming multiple of cube corner reflective elements.




The interior surfaces of the cells


22




a


are isolated from each other by the interior extension of partition walls


23




a


, said interior extension of walls


23




a


having wedge shaped top segment, means for allowing said partition walls to be sonically welded to the corresponding walls of the delineator's opposing side


10




b


. Side


10




a


can be formed having periphery walls


24




a


defining the face portion


20




a


, and providing means to interlock with the corresponding walls


24




b


on the integrally formed opposite side


10




b


. Periphery walls


24




a


can also be integrally formed with textures or beads on its surface to partially fuse with said opposite walls


24




b


on side


10




b


of delineator


10


. The fusion of periphery walls


24




a


and


24




b


as well as partition walls


23




a


and


23




b


can be achieved by means of sonically welding the two sides


10




a


and


10




b


of the delineator


10


. Similarly, side


10




b


comprises top face portion


20




b


, and a planar base portion


25




b


. The face portion


20




b


having similar cell like shapes


22




b


corresponding to the opposing side


10




a


of delineator


10


. Cells


22




b


are isolated from each other by the load carrying raised partition walls


23




b


. Each cell


22




b


having an interior surface with means to integrally include multiple of cube corner reflective elements. The interior portions of the partition walls


23




b


are integrally formed with means for having the top segment fuse to the corresponding wedge shaped top segments of walls


23




a


of side


10




a


. These top surfaces of partition walls


23




b


and the top of periphery walls


24




b


provide means for sonically welding of both sides


10




a


and


10




b


of the delineator


10


.




Sides


10




a


and


10




b


are integrally injection molded with wedge shaped ties


28


, said ties


28


can be folded or split apart, thereby allowing the two sides


10




a


and


10




b


to interlock and/or sonically welded to each others interior side. After the two sides


10




a


and


10




b


are interlocked or welded, air gaps will be retained between the inside surfaces of each two opposing cells


22




a


and


22




b


, thereby allowing maximum retro reflectivity on two opposing traffic paths, via the cube corner reflective elements within the interior surfaces of said cells


22




a


and


22




b


of sides


10




a


and


10




b.






Various types of interlocking devices, welding methods, and types of cube corner reflective elements and method of forming the same are available and can be incorporated in the process of forming delineators or temporary roadway markers or low profile markers, in accordance to the present invention.




Descriptions of suitable cube corner reflective elements are provided in U.S. Pat. No. 3,712,706 to Stamm; U.S. Pat. No. 3,922,065 to Schultz; and U.S. Pat. No. 4,588,258 to hoopman, all of which are incorporated herein by reference in their entireties.




Any desired height, geometric shapes or the overall thickness of the welded sides of the reflective face portion cab be incorporated in the process of the present invention.





FIG. 18

illustrate an isometric view of another preferred delineator


30


, said delineator


30


can be injection molded in one piece with two sides


30




a


and


30




b


, in accordance to the process of the present invention. Delineator


30


has fewer partition walls


33


on each side, thereby allowing the formation of larger reflective cells


32


on both sides


30




a


and


30




b


, of said delineator


30


. Each side


30




a


and


30




b


has a planar and grooved base surface


35


.





FIG. 19

shows an isometric view of yet another delineator


40


, preferably for use on the top or sides of concrete barriers, such barriers are commonly used to separate two directional traffics. The two sides


40




a


and


40




b


of delineator


40


have no interior partition walls. Each side has a reflective portion


41


, integrally including means to form cube corner reflective elements on the interior surface, and grooved planar base surface


45


. By sonically welding the two integrally connected sides


40




a


and


40




b


at the beaded interior surfaces of the periphery walls


44


, thereby delineator


40


is formed.





FIGS. 20 through 25

illustrate yet another novel structure that can be manufactured using the means in accordance to process of the present invention. In

FIG. 20

, there is shown a preferred embodiment of a temporary roadway marker


50


integrally formed in accordance to the present invention. Temporary marker


50


comprises of means to integrally forming the two sides


50




a


and


50




b


near identical to each other. Each side is having an upper segment


58


that resemble a handle bar, which will be called handle bar


58


from hereupon, and a lower body


52


. Body


52


is having two arcuate sides


54


, an inclined planar face


51


with multiple of reflective cell like areas


51




a.






The two rows of cells


51




a


having planar exterior surfaces, and interior surfaces with means to integrally include multiple cube corner reflective elements, said interior surfaces of cells


51




a


, open within hollow cavity means


56


and


56




b


. Body


52


also includes load carrying partition walls


53


and a backside


57


, said backside


57


with beading means for sonically welding the opposing backsides of delineator sides


50




a


and


50




b


, thereby forming temporary marker


50


. The two sides


50




a


and


50




b


are formed interconnected by means of thin ties that are provided at the upper periphery of handle bar


58


.





FIG. 25

shows an isometric view of one side


50




b


of temporary marker


50


, illustrating the planar base surface


55


, integrally including one row of multiple of hollow cavities


56


. Hollow cavities


56


are open directly beneath the lower row of cells


51




a


, thereby providing the means to form cube corner reflective elements on the interior of said lower row of cells


51




a


. Also shown in

FIG. 25

, the backside


57


, which consist of two segments


57




a


and


58




b


. Segment


57




a


is the backside of lower body


52


, and the upper segment


58




b


is the backside of the handle bar


58


of side


50




b


of temporary marker


50


.




Segment


57




a


having textured planar surface that can be provided with beads to be welded to the opposite side of marker


50


, also shown multiple of hollow cavities


56




b


, which are open through said segment


57




a


. Hollow cavities


56




b


are open directly beneath the upper row of reflective cells


51




a


, thereby providing the means to integrally form multiple of cube corner reflective elements on said inside surfaces of upper row of cells


51




a.






The upper segment


58




b


is the interior surface of handle bar


58


. Segment


58




b


is also formed with means to integrally includes multiple of cube corner reflective elements, within periphery edges


59


, said periphery edges


59


provide means to sonically weld the two handle bars


58


, of marker


50


.




Hollow cavities


56


and


56




b


provide the means to have air gaps directly beneath the inside surfaces of each cell like areas


51




a


. Cells


51




a


are separated from each others by the load carrying walls


56




c


, that form hollow cavities


56


and


56




b.






The out side planar surfaces of the cells


51




a


can be either continuous part of the inclined planar face


51


, or slightly recessed bellow the outside surfaces


56




d


of the load carrying walls


56




c.






When the two sides


50




a


and


50




b


are sonically welded fusing the textured or beaded backsides, an air gaps will be retained, both in the upper handle bar


58


and the lower body


52


, thereby providing retro reflectivity, both from the handle bar segment and from the lower body segment, and on two opposing traffic paths. The handle bar segments


58


can be integrally formed from highly transparent and resilient plastic. Temporary marker


50


can also be formed having means for allowing the handle bar to be tore off the lower body, thereby leaving a low profiled reflective marker on the road after the first phase of construction is finished, as shown in

FIG. 23

with a designated temporary marker number


60


.




Various combinations of size, height or geometric shape for markers


10


,


30


,


40


or


50


can be incorporated in the forming process of the present invention.




Preferably marker


50


can have the height of the lower body


52


about 0.40 to 0.60 inch, with a base having width of about 3.0 to 5.0 inches and depth of about 1.0 to 3.0 inches. The upper handle bar


58


can have various shapes and a height of about 1.00 to 1.50 inches, with overall thickness of about 0.05 to 0.10 inch. Pressure sensitive adhesives can be added to the base of all delineators or roadway markers for quick installation of said roadway markings.




In some construction applications where the need for delineator is only for few days and for one-way traffic, one side of delineator


10


or marker


50


can be formed to be effective in such applications.




The present invention includes within its scope a method for making the monolithically formed reflective pavement marker or delineator, comprising the steps:




selecting the pavement marker shape, polymers to be used, types of cube corner reflective elements to be used, body shape, sizes of reflective cells used and the injection molding method to be utilized for said method of making,




providing a tooling means which allow the injection molding of said reflective pavement marker or delineator, integrally including the cube corner reflective elements in one step, said tooling can be made to mold said marker having one color or two colors,




providing hollow cavity means which allow integrally forming the cube corner reflective elements within said pavement marker during said injection molding process,




providing the angular position of said hollow cavity means with respect to the inclined reflective face of said pavement marker to allow uninterrupted ejection cycle during said injection molding of said reflective pavement marker or delineator.




It is understood that various changes or modifications can be made within the scope of the appended claims to the above-preferred method of forming one-piece reflective marker without departing from the scope and the spirit of the invention. The principle processes of this invention are not limited to the particular embodiments described herein. Various embodiments can employ the processes of this invention. This invention is not limited to the exact method illustrated and described; alternative methods can be used to form the intended monolithically formed reflective pavement marker of this invention. Therefore, the invention can be practiced otherwise than as specifically described herein.



Claims
  • 1. A method of monolithically forming one piece reflective pavement or delineator marker including multiple of cube corner reflective elements comprising the steps of:a) providing tooling means which allow injection molding of said reflective pavement marker integrally including the cube corner reflective elements, said tooling means can mold said pavement marker in one stage or two stage injection molding cycle, b) providing hollow cavity means which define the interior load carrying partition walls and allow integrally forming the cube corner reflective elements within said pavement marker during said injection molding process, c) providing the angular positions of said hollow cavity means with respect to the inclined reflective face of said pavement marker allowing uninterrupted ejection cycle during said injection molding of said reflective pavement marker, whereby said reflective pavement marker will be monolithically formed including said cube corner reflective elements and the load carrying partition walls.
Parent Case Info

This a CIP of application Ser. No. 09/385,091, filed Aug. 30, 1999, now U.S. Pat. No. 6,334,734.

US Referenced Citations (10)
Number Name Date Kind
4136991 Clark et al. Jan 1979 A
4726706 Attar Feb 1988 A
5267809 Allan Dec 1993 A
5425596 Steere et al. Jun 1995 A
5449244 Sandino Sep 1995 A
5667335 Khieu et al. Sep 1997 A
5927897 Attar Jul 1999 A
5975706 Nakayama Nov 1999 A
6056426 Jenkins May 2000 A
6126360 May et al. Oct 2000 A
Foreign Referenced Citations (1)
Number Date Country
WO 9111787 Aug 1991 GB
Continuation in Parts (1)
Number Date Country
Parent 09/385091 Aug 1999 US
Child 09/634430 US