Plastic and nonmetallic article shaping or treating: processes – Optical article shaping or treating – Composite or multiple layer
Reexamination Certificate
1999-05-03
2001-07-24
Vargot, Mathieu D. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Optical article shaping or treating
Composite or multiple layer
C264S081000, C427S163100
Reexamination Certificate
active
06264860
ABSTRACT:
BACKGROUND
The present invention is directed to reflective pavement marker without a housing or exterior shell. The reflective members are encapsulated in the housingless body itself This invention also relate to durable abrasion resistant reflective pavement markers. The primary use of this type of pavement marker is for roadway delineation. Pavement markers are commonly agglutinated to the roadway centerline, edgeline or as lane dividers and to serve as perimeter.
Reflective pavement markers generally made using a housing, which is some time referred to as a shell, this housing made of either acrylic, polycarbonate, ABS or other suitable thermoplastics materials. The housing act as a casing to enclose the resinous filler material that, after curing form the structural body of the pavement marker. The reflective member commonly placed either on one side or two opposite sides of the pavement marker facing on coming traffic, generally made as integral part of the housing or agglutinated to the housing then sealed with a metalized coating prior to being filled with the structural resinous body. Reflective members give nighttime visibility of the marker by reflecting headlights of the oncoming traffic.
A marker with a housing not only an added expense to the over all cost of such a product but also tend to chip away from the resinous body due to the severity of traffic impact and the difference in the coefficient of thermal expansions of the two materials, the housing and the resinous body. Additionally, sealing the cube-corner reflectors with a metallic sealer reduces reflectivity considerably.
Previously, attempts have been made to develop a housingless pavement markers. Pavement markers such as U.S. Pat. No. 4,498,733 to Flanagan, U.S. Pat. No. 4,875,798 to May and U.S. Pat. No. 4,208,090 to Heenan use an improved reflective members by using peripheral walls to provide supports and recesses at the bottom of the marker body that form hollowed base. However, unlike this invention, the reflective members are not protected by raised ridges on the outside surface that also help prevent buckling and lift-off the diamond like film coating for abrasion resistance without the need for prior coating of said surface with a polymeric materials. Other deficiency of markers such as 733 is that unless filling the hollowed base of the marker with a sealer material, there is considerable reduction in the adhesion parameter of the marker's base, thereby failure and dislodgement occur due to flexural stresses. The wetting parameter for adhesion of the present marker base to roadway can further be enhanced by spraying coarse sand on the planar base area of the marker body prior to the solidification o f the cast resinous body, as previously proven to be effective, as in U.S. Pat. No. 3,332,327 to Heenan, which is referenced herein. Thus, a need exist for an inexpensive yet have high structural strength and functional reflective marker that solve the problem of housing, having durable reflective members due to very high abrasion resistance diamond like carbon film coating, daytime and night time visibility and full planar base without recesses for durable agglutination to the roadway.
SUMMARY
The present invention satisfies this need by providing a reflective pavement marker that dispenses altogether the use of housing or shell. The present invention comprises a rigid housingless body and a reflective member encapsulated in the inert filled curable resinous body. The body of the marker has a flat top surface and textured planar base surface. The reflective member having inside surface divided by partition walls into several reflective cells, each cell having multiple of cube-corner reflective elements. Each partition wall have a holding pin. The entire reflective cells sealed with a backing sheet allowing the holding pins to protrude outside the backing sheet from a corresponding slots within the backing sheet. The outside planar surface of the reflective member can be integrally divided by a variety of abrasion and impact reducing raised ridges. A reflective cell can be rhomboid, hexagonal or rectangular in shape. Further protection for the reflective cells can be achieved by encapsulating the sealed reflective member in the curable resinous body, leaving only the outside planar surface with raised ridges exposed to roadway environment. The durability of the reflective member can be enhanced further by having the outside planar surface with raised ridges coated with diamond like carbon film, by vapor coating process, for scratch resistance and longer retroreflectivity. The primary objective of the present invention is to provide a housingless reflective pavement marker having at least one reflective member being encapsulated in the curable resinous body with only the outside surface of the reflective member exposed to outside environment, the marker body can have textured planar base surface for better adhesion to the pavement. Still another objective of the present invention is to provide an abrasion resistant pavement marker with at least one reflective member having an inside surface divided into reflective cells by partition and load carrying walls, each wall having a holding pin extending beyond the apices of the cube-corner reflective elements within a cell, said reflective cells being sealed with a backing sheet, said sealed reflective cells and protruding holding pins being encapsulated by the curable resinous body without the need to agglutinate or sonic weld the reflective member. It is yet another desired objective of the present invention is having the raised ridges on the outside surface of the reflective member act as load transferer and to prevent the dislodgement of an abrasion resistant diamond like film coating of said outside surface of the reflective member for scratch resistance.
REFERENCES:
patent: 3627403 (1971-12-01), Hedgewick
patent: 4070095 (1978-01-01), Suhr
patent: 4498733 (1985-02-01), Flanagan
patent: 4726706 (1988-02-01), Attar
patent: 5268217 (1993-12-01), Kimock et al.
patent: 5502593 (1996-03-01), Hedgewick
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