US20090041541A1

US20090041541A1 - Recessed snowplowable pavement marker

Info

Publication number: US20090041541A1
Application number: US11/906,949
Authority: US
Inventors: Harry E. Lowe
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-10-03
Filing date: 2007-10-03
Publication date: 2009-02-12

Abstract

A recessed snowplowable reflective pavement marker is mounted in a shallow elongated groove in a highway surface to expose the marker to headlights of oncoming motor vehicles. The marker has a plastic housing with a pocket for holding the reflector and two sidewalls that support positioning tabs to overlie the uncut pavement. These tabs maintain markers at a fixed depth below the pavement. Two other upstanding sidewalls extend laterally in the groove and terminate at the lower edge of the reflective area of the reflector. These sidewalls prevent adhesive from entering the reflector pocket. The function of the positioning tabs and lateral sidewalls plus the requirement that headlights need only illuminate this reflective area and not the reflector's non reflective base serve to reduce groove depth by 50% less than prior art. This lightweight plastic housing and shallower groove reduce installation costs and enhance marker safety and performance.

Description

RELATED APPLICATION

Provisional Application 60/849,201, filed Oct. 3, 2006 in the name of the same inventor and entitled RECESSED SNOWPLOWABLE PAVEMENT MARKER, disclosed the subject matter as in this currently filed application.

BACKGROUND OF THE INVENTION

The present invention relates to snowplowable pavement markers for use in providing lane delineation, etc. Pavement markers must withstand damage from the vehicle traffic, snowplows, and sundry environmental factors. Two types of snowplowable pavement markers are generally being used now: raised markers and recessed markers.
A typical raised marker utilizes a heavy iron casting embedded within a pavement cutout. The casting has raised laterally spaced inclined longitudinal rails, and a reflector held between and at a lower height than the rails. Both the rails and reflector as mounted protrude slightly above the pavement surface. Raised markers have been used extensively in snow-belt States, as the rails effectively guide the snowplow up and over the reflector. However, many raised marker castings are now being dislodged from the pavement, which then potentially become heavy projectiles capable of causing both vehicle damage and personal injury. In fact, some States have already demanded increased inspection of raised markers and/or their removal.
Recessed markets are mounted below the pavement surface, in long narrow grooves that allow vehicle headlight rays to impact the reflector. These deep grooves tend to collect debris, rain, and snow which obscures the reflective marker surfaces and reduces or precludes reflectivity. Moreover, deep grooves can errantly steer the wheels of motorcycles and small cars. Deep grooves also take longer to clean out than more shallow grooves.

OBJECTS AND FEATURES OF THE INVENTION

General objects of this invention are to provide a recessed marker that overcomes problems found in the prior art markers, including: being more economically and accurately installed and less costly to maintain; having improved reflectivity for good visibility; and being of lightweight construction for minimizing damage should the marker become dislodged from the pavement.
Detailed features of the invention include: (1) reducing the groove depth by aligning the bottom groove face generally with the lower edge of the marker reflective surface, thereby minimizing the groove depth. The prior art groove is significantly deeper because it must account for the non-reflective height of the reflector structure and the thickness of reflector adhesive. (2) reducing marker and tire wear/damage because of a lower reflector profile. (3) increasing the groove width to provide easier marker installation and to increase water drainage from the groove.
Another general object of the invention is to allow for the .use of multiple or tandem reflectors spaced longitudinally apart in a single shallow depth groove, for-improving reflective efficiency.

SUMMARY OF THE INVENTION

The housing is made from strong lightweight plastic, such as polycarbonate (PC) or acrylonnitrile-butadiene-styrene (ABS), having an upwardly open pocket defined by a base and interconnected side walls that receive and hold the reflector. The two lateral side walls cross the groove and protrude from the base to terminate at the lower edge of the reflective area of the reflector. The other side walls rise upwardly beyond the top of the reflector. Positioning tabs project laterally off of these side walls operable to overlie the uncut roadway pavement adjacent the groove and thereby accurately position the marker so that the top of the reflector will be at a desired clearance below the uncut pavement surface and the lower reflective edge will be generally aligned with the bottom face of the shallow groove.
Thus, after adhesive has been admitted into the secondary groove, the marker can be positioned in the groove, whereupon tab contact with the uncut pavement surfaces will accurately and consistently locate the marker reflector below the uncut pavement surface and the marker will be firmly held thereat when the adhesive sets. The use of positioning tabs, lateral side walls, and a slightly deepened secondary groove allows the longitudinal shallow groove depth to be approximately 50 percent less than that of typical prior art grooves.
The invention can be enhanced even further from a cost benefit/reflectivity standpoint by installing tandem markers, each spaced two or three feet apart in the same longitudinal groove.
Generally, any reflector might be located approximately three/five feet from the ends of the shallow groove, which for a single reflector might therefore be approximately six/ten feet in length; while tandem reflectors might be positioned in longer grooves, with possibly three/four feet between the groove ends and the nearest reflector and with two/three feet separation between adjacent reflectors.
The inventive marker can be modified to accommodate recessed reflectors of different sizes and/or configurations.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features or advantages of the invention will be more fully understood and appreciated after considering the following description of the invention, which includes the accompanying drawings, wherein:

FIG. 1 is a perspective view, part broken away and in section, of the roadway pavement having the line of sight shallow and secondary installation grooves cut therein, the marker with its positioning tabs and reflector in place, and the adhesive holding the marker in the pavement;

FIG. 2 is an exploded perspective view of the pavement and line of sight shallow and secondary grooves cut therein, and the marker housing and reflector components in exploded association;

FIG. 3 is a cross-sectional side view of a prior art marker installed in a conventionally cut pavement groove;

FIG. 4 is a cross-sectional side view of the subject marker installed in the proposed cut and adhesive filled pavement groove;

FIG. 5 is a sectional view taken from line-5-5 in FIG. 4;

FIG. 6A is a plan view of a single inventive marker shown mounted in the cut pavement groove;

FIG. 6B is a schematic illustration of the groove and pavement profiles illustrated in FIG. 6A:

FIGS. 7A and 7B are illustrations similar to FIGS. 6A and 6B, except of a tandem or two marker setup;

FIGS. 8A and 8B are illustrations similar to FIGS. 6A and 6B, except of a tandem or three marker setup;

FIG. 9 is a schematic illustration of a vehicle approaching tandem markers with illuminating and reflecting light rays included;

FIG. 10 is a chart illustrating the reflectivity of inventive markers as a vehicle approaches.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides that a traditional line of sight groove 10 would be cut in the pavement 12, but to a shallower depth to where the marker 14 is to be located, where then a short secondary deeper groove 16 would be cut sufficient to mount the marker 14 therein while yet having marker top clearance 18 below the adjacent uncut pavement surface 19. The marker 14 will comprise a housing 20 having laterally extended tabs 22 sized to rest on the adjacent uncut pavement surface 19 when the marker is positioned in the secondary groove 16 while yet having the marker top clearance 18 below the uncut pavement surface. This positioned marker will also preferably have the lower reflective edge 24 of the reflector face 26 generally lined up with the bottom face 28 of the shallow line of sight groove 10.
Further, after a suitable adhesive or epoxy 30 is in the secondary groove 16, the marker need only be pressed into it until the positioning tabs 22 rest on the adjacent uncut pavement surface 19, whereupon the marker will be accurately located relative to the pavement and securely held therein when the adhesive or epoxy sets.
The prior art and inventive recessed markers are in part compared in FIGS. 3 and 4. Thus, a line of sight groove 10 is cut in the pavement for both markers, starting at zero depth at both line of sight groove ends (shown in FIGS. 6B. 7B and 8B) and extending progressively to a deepest medial portion, such as where the markers might be secured by an effective adhesive or epoxy.
However, the line of sight groove depths 31 are clearly different for the prior art and present markers, as the prior art marker 14PA sits on and is held by adhesive to the bottom face 29 of its groove (see FIG. 3) while the depth of the present marker 14 is determined when the positioning tabs 22 rest on the adjacent uncut pavement surface (see FIGS. 4 and 5).
The reflector housing 20 might be of unitary construction with a defined upwardly facing pocket 32 defined by a base 34 and opposed pairs of upstanding side walls 36 and 38. The positioning tabs 22 project outwardly of the pocket from the upper portion of the side walls 36. The tabs further might be narrow as a neck at the top of its side wall, to easily break away without dislocation of the marker. Also, the anchor means or tabs 42 project outwardly away from the lower portions of the side walls 38 and away from pocket 32. The anchor means might be comprised as many separate spaced apart projections off of the housing or projecting flanges across the entire width of side walls 38.
The invention further provides that the secondary groove 16 is cut to the width and depth needed to have the reflector housing 20 fit therein, and yet be spaced from the secondary groove pavement surface 40. Adhesive such as epoxy can be admitted into the secondary groove, so that after the housing is pressed into the adhesive, the adhesive can flow around the anchor tabs so that as soon as the adhesive sets, the housing and its reflector will be firmly secured relative to the pavement.
The sizing and arrangement of these components including the tabs 22 and reflector mounting relative thereto will preferably provide that the recessed marker can be positioned in the secondary groove so that the bottom face 28 of the line of sight cut groove 10 will generally line up with the lower edge 24 of the reflective surface 26 on the held reflector 14.
Generally, the top of the reflector should be recessed approximately 0.12 inches below the uncut pavement surface. The vertical height of the reflective surface might be approximately 0.25-0.30 inches. The height of the adhesive fill 30 in the secondary groove 16 should be possibly 0.05-0.15 inches below the top of transverse side walls 38.

Claims

1. A recessed pavement marker component, comprising a unitary housing having an upwardly facing pocket defined by a base and opposed pairs of upstanding side walls; positioning tabs projected outwardly of the pocket from the upper portion of one pair of the side walls; and anchor means projected outwardly of the pocket from the lower portions of the transverse pair of side walls, whereby a reflector can be secured in the housing pocket to define the recessed marker, whereby said marker can be positioned in appropriate grooves in the pavement until the positioning tabs overlie the uncut pavement surface and adhesive in the groove sets to securely hold the housing in the pavement via the anchor means.

2. A recessed pavement marker according to claim 1, further including the anchor means comprising a plurality of separate spaced apart transversely arranged projections from both of the transverse side walls.

3. A recessed pavement marker according to claim 1, further comprising each positioning tab being connected via a narrow neck to the top of its side wall, to easily break away when the housing is set in place as located and without dislocation of the marker.

4. A recessed pavement marker according to claim 3, further including the anchor means comprising a plurality of separate spaced apart generally parallel transversely arranged projections from both transverse side walls, whereupon the reflector will lie completely below the level of the uncut pavement surface.