GB1580725A

GB1580725A - Road marker

Info

Publication number: GB1580725A
Application number: GB17158/77A
Authority: GB
Original assignee: Amerace Corp
Current assignee: Amerace Corp
Priority date: 1976-04-30
Filing date: 1977-04-25
Publication date: 1980-12-03
Also published as: JPS52144124A; AU2478577A; AU509275B2

Description

(54) ROAD MARKER (71) We, AMERACE CORPORATION a Corporation organized and existing under the laws of the State of Delaware United States of America, of 245 Park Avenue, New York, New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performd, to be particularly described in and by the following statement:: In United States Patent No. 3,332,327, there is disclosed a road marker adapted to be placed on highways and in which the road marker front face is inclined at a predetermined angle to the roadway surface so that a self-cleaning effect is provided by virtue of that predetermined angle, whereby that road marker achieves initial high optical efficiency and the optical deterioration arising out of contact with tires of oncoming vehicles is substantially reduced by allowing the face to be periodically wiped clean by contact with such vehicles. In addition, there is disclosed in that patent a cube-corner reflex reflective optical system in which the cube axes of the cube-corner reflective elements are inclined so as to be substantially coincidental with the nominal incoming refracted ray. Road markers made in accordance with U.S.Patent No. 3332327 and similar to the structure disclosed therein have been extremely successful in operation, and several millions of them have been installed, primarily in areas where no snowplowing of the roads is required. That earlier road marker, while highly effective as a nighttime signal, is substantially ineffective as a daytime marker, because of the nature of its construction, and, in particular, the large metallized area of the reflective portion thereof, which metallizing is required because of the epoxy fill. Also, the height of the earlier road marker precluded its practical use under snowplow conditions.

Furthermore, that prior marker involves a tradeoff between abrasion-resistance and self-cleaning or wiping characteristics whereby given the materials used there are limits to the improvement that can be made in one quality without adversely affecting the other.

Also, where a road is constructed of a particular material, or is newly installed asphalt, the prior marker has caused deterioration of the road surfaces. Some users have recommended delaying installation of such markers for a year to allow the road to cure. In an attempt to overcome these problems caused by unsatisfactory road surfaces or newly installed surfaces, the markers of U.S. Patent No. 3332327 were installed with an impact-absorbing pad. However, the use of the impact-absorbing material still did not completely resolve the problem.

In U.S. Patent No. 3,833,285, issued September 3, 1974, there is disclosed an optical system for use with cube-corner-type reflectors, wherein the reflectivity of the reflector is increased by enlarging one of the three dihedral angles forming the cube-corner element, thereby improving the visibility of the reflector at a selected wider observation angle.

British Patent No. 1189055 discloses a cellular system for reflectors in which, in one embodiment, a cellular reflector member is provided on an underlying metal casting for providing a snow-plow-type marking. That reflector design is capable of increased daylight reflectivity. Road markers have been used in which three substantially large cells are provided, the cells being provided by walls which extend beyond the apices of the cube-corner elements and in which the lens member is affixed to a substantially flat support wall lying thereunder. These prior markers presented an undesirable high profile and other disadvantages.

According to the present invention, there is provided a reflex reflector incorporating a base member and a transparent light transmitting lens member supported thereon wherein said base member includes a support surface having a plurality of isolated open pockets therein with portions of said support surface surrounding each said pocket and wherein said lens member is a one piece member extending over substantially all of the pocket openings and has a rear face provided with a plurality of discrete groups of reflex-reflecting elements and a front face, said lens member being affixed to said base member with portions of said rear face between the discrete groups in contact with the pocket surrounding portions of said support surface and each of said groups of reflex-reflecting elements located in a corresponding one of said pockets to form a plurality of discrete reflex reflector zones capable of reflecting light emanating from a source and impinging upon said front face of said lens member back toward the light source.

According to a further aspect of the invention, there is provided a road marker comprising a reflex reflector, said reflex reflector incorporating a base member and a transparent light transmitting lens member supported thereon, wherein said base member includes a support surface having a plurality of isolated open pockets therein with portions of said support surface surrounding each said pocket and wherein said lens member is a one piece member extending over substantially all of the pocket openings and has a rear face provided with a plurality of discrete groups of reflex-reflecting elements and a front face, said lens member being affixed to said base member with portions of said rear face between the discrete groups in contact with the pocket surrounding portions of said support surface and each of said groups of reflex-reflecting elements located in a corresponding one of said pockets to form a plurality of discrete reflex reflector zones capable of reflecting light emanating from a source and impinging upon said front face of said lens member back toward the light source.

The invention, together with further objects and advantages thereof, can best be understood by reference to the following specification, taken in connection with the accompanying drawings, in which: Figure 1 is a partially sectioned perspective view of one embodiment of a road marker constructed in accordance with the present invention; Figure 2 is a top plan view of the marker of Figure 1; Figure 3 is an end elevational view of the marker illustrated in Figures 1 and 2; Figure 4 is an enlarged view of the rear face of a lens member forming part of the marker of the present invention, taken in a direction perpendicular to the rear face thereof; Figure 4A is a fragmentary view, on an enlarged scale, of a portion of the rear reflective surface of the lens member within the circle 4A of Figure 4, but taken in a direction parallel to the cube axis of the elements;; Figure 5 is a top plan view of the base of the marker of the present invention; Figure 6 is a side elevational view of the base of Figure 5, as viewed from the right-hand side thereof; Figure 7 is a greatly enlarged cross-sectional view of the base, taken along the line 7-7 in Figure 5, with the lens member of Figure 4 shown mounted in place on one side of the base; Figure 8 is a greatly enlarged cross-sectional view of the lens member taken along the line 8-8 in Figure 4 and rotated approximately 90 degrees; Figure 9 is an enlarged fragmentary sectional view of the lens member taken along the line 9-9 of Figure 4; Figure 10 is an end elevational view of a second embodiment of the road marker of the present invention; Figure 11 is a top plan view of a third embodiment of the road marker of the present invention;; Figure 12 is an end elevational view of the marker of Figure 11; Figure 13 is a top plan view of a-fourth embodiment of the road marker of the present invention Figure 14 is an end elevational view of the marker of Figure 13; Figure 15 is an enlarged view of the rear face of a second embodiment of lens member forming a part of the marker of Figure 13, taken in a direction perpendicular to the rear face thereof; Figure 16 is a top plan view of the base of the marker of Figure 11; Figure 17 is a side elevational view of the base of Figure 16, as viewed from the right-hand side thereof; Figure 18 is a fragmentary bottom plan view of the base of Figures 16 and 17; Figure 19 is a greatly enlarged view in vertical section taken along the line 19-19 in Figure 13; ; Figure 20 is a greatly enlarged view in vertical section taken along the line 20-20 in Figure 15, and rotated approximately 90 ; Figure 21 is an enlarged fragmentary sectional view of the lens member of Figure 15, taken along the line 21-21 therein; Figure 22 is a diagrammatic view of a roadway illustrating prior art arrangements of markers utilizing different type of markers for daytime and nighttime visibility; and Figure 23 is a view similar to Figure 22, illustrating an arrangement of markers utilizing only the markers of the present invention for both daytime and nighttime visibility.

A road marker constructed in accordance with the present invention is shown in perspective at 10 in Figure 1 and includes a body or base 20, of an opaque, light-diffusing synthetic resin having mounted thereon two lens members of light-transmitting synthetic resin, each generally designated as 30.

The base 30 is substantially solid and is formed as a one-piece member to provide a durable structure capable of withstanding impact forces applied to the road marker when it is struck by a tire of an oncoming vehicle.

The road marker 10 is employed to provide a marking on a generally horizontal roadway surface, the marking being visible from an oncoming vehicle on the roadway to delineate traffic lanes and for edge delineation, as is well recognized in the art. In addition, the marker 10 of the present invention may be utilized with metal base members.

Referring now more particularly to Figures 5, 6 and 7, it will be seen that the base 20 has a generally horizontal bottom surface 21. In order to prevent sinks or shrink stresses in molding, the base 20 may be provided with a plurality of molding recesses 21A (Figures 5 and 7). The base further includes a pair of generally vertically disposed end walls 22 and 23 (Figure 2), and a generally horizontal top wall 24 having a rectangular channel 24A extending from one end wall 22 to the opposite end wall 23.

There is provided a pair of inclined support walls 25, disposed at opposite sides of the base 20, and positioned such that in use, they will be facing the direction of oncoming vehicles. Each of these support walls 25 has a plurality of recesses 26 formed therein, which recesses have substantially rectangular openings intersecting the plane of the wall, the portions of each support wall 25 between the recesses 26 defining partitions or dividing portions 25A. The recesses or pockets 26 and the support wall 25 cooperate with the overlying lens member 30 in a manner hereinafter described.

The base 20 further includes side edges 27 and 28 disposed on the opposite ends of each of the respective end walls 22 and 23, the side edges 27 and 28 extending outwardly beyond the support walls 25, and defining a channel between the opposite side edges and the adjacent support wall 25 disposed therebetween. The base 20 also includes a tab opening 29 formed in the end walls 22 and 23 adjacent to the respective inclined support walls 25 for purposes of facilitating the alignment of the lens member 30 during attachment thereof to the base 20.

The lens member 30 which provides the reflective structure for reflecting light back toward the source thereof, thereby rendering the marker highly visible at night, is best illustrated in Figures 4, 7, 8 and 9. The lens member 30 is formed of a light-transmitting synthetic resin and includes a substantially planar front face 31 and a rear face 32. As illustrated, the lens member 30 is generally rectangular and is intended to be positioned in the channel provided by the side edges 27, 28 and the support wall 25.

The rear face 32 of the lens member 30 is provided with a peripheral edge portion 33 which extends about the entire periphery of the lens member 30 (Figure 4) and includes a portion 33A which is originally in the form of a generally triangular bead (Figures 8 and 9).

The rear surface 32 further is provided with a plurality of dividing portions 34, the dividing portions 34 intersecting the peripheral edge portion 33 at equally spaced distances therealong, thereby dividing the lens member into a plurality of generally rectangular areas circumscribed by the peripheral edge portion 33 and the dividing portions 34. As illustrated, the dividing portions 34 originally may include a raised triangular sealing bead 34A, and hereinafter, in the specification, for convenience, the dividing portions 34 may be referred to as "dividing ribs".

The lens member 30 is intended to be positioned over the inclined support wall 25 of the base 20 and rigidly secured thereto, preferably by ultrasonic welding. When properly positioned, each of the rectangular areas circumscribed by the peripheral edge portion 33 and dividing portions 34 will coextensively overlie and be in registry with the rectangularshaped openings of the recesses or pockets 26 formed in the support wall 25, while the dividing portions 34 will overlie the dividing portions 25A of the support wall 25.

When the lens member 30 is ultrasonically welded to the base 20, the sealing beads 33A and 34A become substantially flattened as a result of the energy imparted thereto during the ultrasonic welding process, whereby the peripheral edge portion 33 directly abuts the support wall 25, as best illustrated in Figure 7, and provides a substantial welded surface area visible through the transparent lens member 30.

Similarly, the dividing ribs 34 will become substantially flattened as they are sealed to the underlying dividing portions 25A of the support wall 25.

The lens member 30 also includes an outwardly extending tab 37 adapted to be positioned within the tab opening 29 on the base 20, and serves as a locator to fix the lens member 30 in position prior to welding.

After welding the lens member 30 to the base 20, each of the dividing wall portions 25A of the support wall 25, and the peripheral portion thereof, in cooperation with the dividing ribs 34 and peripheral edge portion 33, provide a plurality of hermetically sealed cells 35 having a rectangular configuration when viewed in a direction normal to the front face 31.

The road marker 10 is provided with a retro-directive cube-corner-type reflector system to effect the signal function of reflecting light back to the driver of an oncoming vehicle whose headlights illuminate the marker.

As best seen in Figure 4, the rear face of the lens member 30, in those rectangular areas circumscribed by the dividing ribs 34 and peripheral edge portion 33, is configured to provide a plurality of cube-corner-type retrodirective reflector elements 40.

In the embodiments illustrated herein, the cube-corner elements 40 are intended to be generally rectangular when viewed in a direction along the line of the cube axis, as best illustrated in Figure 4A.

Each of the cube-corner elements 40 includes cooperating faces 41, 42 and 43, respectively, the faces intersecting to form first and second and third dihedral angles in a manner well known to those skilled in the art. In the preferred embodiment illustrated, two of the dihedral angles would be on the order of substantially 90" whereas the third dihedral angle would be formed at an angle significantly different from the first and second dihedral angles, so that the light reflected by such cube-corner element is caused to be diverged to a greater extent in one direction than in the other. One such structure is set forth in greater detail in U.S. Patent No. 3,833,285.

In the illustrated embodiment, the different dihedral angle is formed between those faces designated as 41 and 42 in Figure 4A, whereby the reflectivity of the reflector will be substantially increased at a greater observation angle, as more fully demonstrated hereinafter.

As seen in Figure 7, the apices of the cube-corner reflective elements 40 extend beyond the peripheral edge portion 33 and the dividing ribs 34, and into the cell 35, when the lens member 30 is secured to the base 20. Although in the embodiment illustrated the cells 35 are substantially large and open, it should of course be understood that the pockets 26 may be recessed less deeply than indicated, and, in fact, the apices of the cube corners 40 may contact the underlying surface 26A defining the interior boundary of the recess 26 thereby further to strengthen the lens member 30 and provide additional support therefor as the lens member is contacted by a tire of an oncoming vehicle.

To facilitate installation of the marker on an underlying roadway surface, or on a metal casting in the event the marker 10 is used in snowplow country, an adhesive impact-absorbing material or pad 15 is secured to the bottom surface 21 of the base 20. The pad 15 may comprise an elastomeric polymeric adhesive material such as, for example, butyl rubber. A protective sheet of release paper 16 is applied to the bottom of the pad. In use, the paper 16 is peeled from the pad 15 and the marker 10 pressed onto the roadway surface. In installation it may be desirable to use a suitable primer on the roadway to enhance securement of the marker. Satisfactory butyl tape, T-9463, and primer, P-1130, are products of Protective Treatments, Inc. of Dayton, Ohio.

After a road surface is rimed, the marker is positioned on the primed road surface with light pressure, after which greater pressure may be applied by driving slowly over the marker with one tire of a service truck. The use of the adhesive pad 15 greatly facilitates installation of the marker 10 on the roadway surface. More particularly, this arrangement permits rapid installation of the markers from a slowly moving vehicle, thereby obviating lane closures and their attendant inconvenience and safety hazards which were necessitated with prior art intallation techniques.

It is believed that the impact-absorbing material 15, together with the low profile of the marker 10 achieved by the low height thereof relative to the roadway surface, effects both a reduction and absorption of some of the impact energy normally transmitted through to the underlying road surface.

It is also believed that the low profile allows the marker 10 to be ingested by a tire body so that the tire body rolls over the marker 10 and is still partially supported by the roadway surface, rather than causing the full load of the tire to impact upon the marker, which is what is thought to happen with existing markers of a higher elevation. Moreover, it is further believed that the low profile, in combination with the impact-absorbing material 15 on the bottom surface 21 of the base 20, renders the individual cell structure formed by the combined lens member 30 and base 20 more resistant to impact damage.

An important feature of the present invention in leading to a reduction of the overall height of the marker is the provision of the recesses 26 in the support wall 25 rather than by providing the cells in a fashion where the walls are carried by the lens member 30 and extend beyond the apices of the cube corners 40. This feature of the present invention permits reduction in the overall height of the lens member 30, and particularly the elements 40 thereof, relative to the bottom surface of the base 20.

It will be observed with reference to Figure 8 that the cube-corner elements 40 disposed toward the lower end of the lens member 30 extend outwardly to a greater extent from the rear wall 32 of the lens member 30 than do those reflector elements disposed toward the upper end. The plane defined by the apices of the elements 40 is parallel to the front face 31, but is inclined at an acute angle a to the rear face 32 (Figure 8). This feature allows a further reduction in overall height of the marker, without requiring undesirable undercuts in the base 20, which otherwise would have to be provided therein if the cube corners 40 at the upper portion of the lens member extended outwardly as far as the lower elements.

There is an optimum balance obtained in maintaining optical effectiveness by limiting abrasion and achieving adequate wiping or cleaning of the front face of the marker upon contact by a moving tire. Such optimum balance is achieved when the angle of the front face of the lens member is disposed at approximately 30 to the horizontal, with a satisfactory result being obtained where such angle is approximately from 15 to 45". In general, abrasion resistance is directly proportional to the front face angle while self-cleaning ability is inversely proportional to the front face angle.

However, the abrasive action on the front face of the marker due to tire contact becomes an even more critical factor than the aforementioned wiping or cleaning action when the marker is used where abrasive materials are purposely placed on the road. Thus, in an area where salt or sand is put on the road during the wintertime, the wiping action by such abrasive materials in contact between the tire and front face of the lens member causes more serious damage to the front face than is the case where those markers are located in other areas of the country where such abrasive materials are not on the roadway.In order to minimize the loss of reflectivity due to abrasion, and to prolong the reflective qualities of the marker under these conditions, the front surface 31 of the lens member 30 of the present invention is preferably inclined at an angle of 45" relative to the horizontal surface 21 of the base 20. It will be appreciated that the effects of abrasion may be further minimized by increasing the angle of the front face above 45 ; however, it is believed that at front face angles above 60 , the cleaning and wiping action by tire contact will be inadequate to maintain optical effectiveness.

It is also known that the front surface reflection loss due to the inherent nature of the material of the lens member itself is less at 45" than at 300. As an example, the typical front surface reflection loss of a road marker in which the front surface of the lens is located at 300 to the horizontal would be approximately 34%, whereas the front surface loss with the reflector at 450 to the horizontal would be only 12%. Also, by inclining the front face of the marker at 45 , there is a smaller area exposed to contact by automatic tire studs or stones carried in the tire treads, and also the pressure on the front surface is reduced.Further, by inclining the front face of the marker at 45 , it is possible to further reduce the overall height of the marker because there will be a lesser inclination of the cube axis relative to the horitonal than is provided in U.S. Patent 3332327, and it will not be necessary to tilt the cube-corner elements 40 as much.

To further protect the front surface 31 from excessive abrasion, and particularly from a grinding action by sand or salt being disposed on the roadways, the front surface 31 of the lens member 30 may be provided with abrasion-limiting means; in the illustrated embodiment such means comprise a plurality of outwardly extending ridges 45. The operation of the ridges 45 is set forth in the copending application 16861177 serial No.

1578834. The ridges 45 are disposed directly over and in alignment with the dividing ribs 34 on the back face 32 of the lens member 30, whereby the ridges 45 do not interfere with the operation of the reflex portions 40 on the lens member. The ridges 45 may be integrally molded with the lens member 30, or, if desired, they could be made of a more abrasion-resistant material than the lens member and thereafter secured to the lens member 30 by welding or adhesive, thereby to provide further protection for the front surface of th marker.

As previously described, the side edges 27 and 28 extend outwardly beyond the inclined support walls 25 of the base 20, and provide a channel between the side edges and the support wall 25 within which is disposed the lens member 30. The side edges 27 and 28 provide further structural support and protection for the lens member 30 adjacent those areas in which the ultrasonic welding occurs at the corners of the marker, thereby serving to substantially protect the integrity of the marker at those points. It will also be noted that the side edges 27-28 and the front edges of the protective ridges 45 lie in the same plane, in effect defining a protective barrier for the front face 31 of the marker 10.

The marker 10 also may be provided with a metal cover plate 19 to overlie and protect the entire top wall 24 thereof, the cover plate 19 also extending beyond and overlying the upper edge of the lens member 30, as best seen in Figure 3. The metal cover plate 19 is intended to be used on those embodiments of the marker 10 which are to be installed in a metal casting and subjected to possible contact by studded snow tires passing over the top of the marker, the cover plate serving to provide additional protection against such studs.

The cover plate 19 may be adhesively secured to the top wall 24 or, alternatively, a second impact-absorbing pad (not shown) may be fixedly secured therebetween. As the use of tire studs becomes more widely prohibited, the metal plate and recessed channel may be eliminated.

The rectangularly shaped longitudinally extending channel 24A provided in the cover plate 19 and in the top wall 24 is adapted to receive a retaining member in a well-known manner, the retaining member serving to further hold the marker in place on the underlying metal casting, if such retaining member is desired.

The arrangement of the lens member 30 with its peripheral transparent edge portion 33 and dividing ribs 34, and the underlying light-diffusing opaque support wall 25, imparts substantial daytime visibility to the marker 10, rendering it of greater utility than prior markers.

In the illustrated embodiment, the total area occupied by the peripheral edge portion 33 and the dividing ribs 34 is substantially equal to that occupied by the retrodirective reflector elements 40 in those areas circumscribed by the edge portion 33 and the dividing ribs 34.

By using rectangular retrodirective cube-corner elements 40 and rectangular cells 35, maximum use of the area of the lens member 30 is accomplished, as there will be no partial cube-corner elements along the edge of any cell, while at the same time it is possible to substantially completely fill the area circumscribed by the peripheral edge portion 33 and the dividing ribs 34 with retrodirective reflective elements 40.

Further, the use of the rectangular cells 35 and square reflector elements 40 permits the use of vertical side wall surfaces in each recess 26 of the marker, if desired, whereby substantially the full width of the marker 10 is provided with complete reflective elements.

The opaque, light-diffusing base 20 serves to reflect daylight impinging thereon to an observer. At a distance, the uniform spacing of the dividing ribs 34 and dividing wall portions 25A causes the marker to appear as a substantially uniform reflective body, with the cells 35 tending to disappear to the eye of the observer under daylight conditions.

Alternatively, under nighttime driving conditions, the uniform size and spacing of the cells 35 causes the marker to appear as a uniform reflective member, the dividing ribs 34, which improve daytime visibility, tending to disappear under evening driving conditions.

To achieve these benefits, together with a low profile, it is believed that the maximum rectangular projected dimensions of each cell 35 should not exceed about .3 inches high and about .75 inches wide, with the preferred construction providing cells substantially square in projected view with a projected height of approximately .3 inches and a projected width of approximately .36 inches.

While the preferred embodiment has eight such rectangular cells therein, it is believed that a minimum of five cells is required in order to obtain the substantial daytime reflective qualities achieved by the present marker and to preserve nighttime reflectivity of the marker in the event of damage to one or more of the cells, which would cause it to lose its hermetic seal and thereby ultimately render it optically ineffective.

Despite having at least half of its projected area devoted to wall structure for providing strength and daytime visibility, the marker 10 of the present invention also provides substantially improved reflectivity over the marker of U.S. Patent 3332327. As an example, the table set forth herebelow indicates representative figures for typical units of the marker of U.S. Patent 3332327 contrasted with the present invention at two different observation angles. It will be observed that a marker of the type of the present invention is almost two and one-half times brighter at a .20 observation angle, corresponding to a distance of approximately 500 feet, and almost five times brighter at a .40 observation angle, corresponding to a distance of about 250 feet.

REPRESENTATIVE BRIGHTNESS Candlepower per Footcandle per Square Inch of Reflector Observation Angle U.S. Patent 3,332,327 Present Invention .2" 3 8 .4" 1.5 8 The increased brightness of the present invention permits the reduction in height of the marker without any loss in specific intensity, as indicated in the table below.

SPECIFIC INTENSITY Candlepower per Footcandle Observation Angle U.S. Patent 3,332,327 Present Invention .2 6 8 .4" 3 8 Moreover, the specific intensity of the present invention is significantly greater at .4" observation angle than that of the prior marker for a smaller area, thereby causing the marker of the present invention, though of a low profile, to be substantially brighter in appearance.

In the embodiment illustrated, the height of the base 20 from the bottom horizontal surface 21 to the top wall 24 is approximately .43 inches; the pad 15 is approximately .06 inches, for a total height above the roadway of approximately .49 inches, as contrasted with the overall height of the marker of U.S. Patent 3332327 of approximately .72 inches.

Moreover, an epoxy adhesive normally was utilized to apply the marker of U.S. Patent 3332327 to the roadway, or, in those instances in which a pad was used, there would be a further increase in height of the prior marker of up to .06 inches. Thus, the present invention represents a reduction of about 38% in overall height.

The front face of the lens member 30 is disposed at an angle of approximately 45" to the horizontal surface 21, while the support wall 25 is inclined at an angle of approximately 41 .

The ridges 45 on the front face 31 of the lens member 30 are positioned at angles of approximately 53" relative to the horizontal surface 21 and similarly the side edges 27 and 28 forming extensions of the side walls 22 and 23 also are inclined at angles of approximately 53" relative to the underlying surface 21. It will be apparent from the foregoing that the outer edges of the ridges 45 and the side edges 27 and 28 therefore are substantially coplanar and provide a protective area for the front surface of the lens member.

The base 20 may be made of a thermoplastic resin such as acrylonitrile butadiene styrene (commonly known as ABS), glass-filled ABS, methyl methacrylate or rubber-modified methyl methacrylate, commonly known as Plexiglass DR (Trade Mark), or lexan, or may be made of a thermosetting material and be adhesively mounted. The lens may be of methyl methacrylate or a rubber-modified methyl methacrylate or a polycarbonate such as lexan.

Normally, the lens and base will be chosen to provide the same colors, day and night, with the specific color being determined by the specific function of the marker, e.g., lane delineation vs. median edge delineation.

The embodiment of the road marker illustrated in Figure 10 is primarily intended to be used independently of any metal housing or casting. In that embodiment the top wall 24, rather than being generally horizontal, as in the first embodiment illustrated in Figure 1, instead has surfaces 47 and 48 which incline upwardly in the same general direction as the support walls 25, the inclined surfaces 47 and 48 forming a crown above the height of the lens member to provide additional reflective body area for reflecting daylight back to an observer. The metal cover plate 19 would of course not be used with this marker which would preferably be used under non-snowplowable conditions. The added crown at the top of the base 20 increases the overall height of the marker by about another .06 inches, whereby the total height of such marker would be approximately .55 inches.

Referring now to Figures 11, 12 and 16 through 19 of the drawings, there is illustrated another embodiment of the road marker of the present invention, generally designated by the numeral 50, and comprising a body or base 60 of an opaque, light-diffusing synthetic resin having mounted thereon two of the lens members 30. The base 60 is substantially solid and is formed as a one-piece member to provide a durable structure capable of withstanding impact forces applied to the marker 50 when it is struck by a tire of an oncoming vehicle.

More particularly, the base 60 has a generally horizontal bottom surface 61 having a plurality of generally rectangular molding recesses 62 formed therein for the purpose of preventing sinks or shrink stresses during the molding of the base member 60. The molding openings 62 extend well up into the base 60 and cooperate to define therebetween a plurality of substantially vertically extending partitions or walls 63 and a pair of upstanding opposed side walls 64 and 68 interconnected by a top wall 69 which is peaked or gabled to form two halves each inclined at a slight angle to the plane of the bottom surface 61. There is also provided a pair of inclined support walls 65, respectively disposed at opposite sides of the base 60, and positioned such that in use they will be facing the directions of oncoming vehicles.Each of the support walls 65 has a plurality of recesses 66 formed therein, which recesses have substantially rectangular openings intersecting the plane of the outer surface of the support wall 65, the portions of each of the support walls 65 between the recesses 66 defining septa or dividing portions 67.

The top wall 69 of the base 60 has inclined top surfaces 70 and 71 which respectively extend upwardly from the upper ends of the outer surfaces of the support walls 65 and intersect along a line substantially parallel to the support walls 65 and midway therebetween. Each of the end walls 64 and 68 is provided at the upper end thereof with upstanding shoulders 72 and 73 which respectively project upwardly above the top surfaces 70 and 71 of the top wall 69 and outwardly beyond the outer surfaces of the support walls 65, the shoulders 72 cooperating with one of the support walls 65 to define a channel therealong and the shoulders 73 cooperating with the other of the support walls 65 to define a channel therealong.Preferably, each of the side walls 64 and 68 is also provided with a tab opening 74 therein adjacent to the corresponding inclined support wall 65 for purposes of facilitating the alignment of the lens members 30 during attachment thereof to the base 60.

The lens members 30 were described above in connection with the marker 10, and each of the lens members 30 is mounted on the base 60 and cooperates therewith in the same manner as was described above with respect to the base 20 of the marker 10. More particularly, each of the lens members 30 is positioned over one of the inclined support walls 65 of the base 60 and rigidly secured thereto, as by ultrasonic welding, with the rectangular areas circumscribed by the peripheral edge portion 33 and dividing portions 34 coextensively overlying in registry with the rectangular-shaped openings of the recesses or pockets 66 formed in the support walls 65, while the dividing portions 34 overlie the dividing portions 67 of the support walls 65.When the lens members 30 are ultrasonically welded to the base 60, the sealing beads 33A and 34A become substantially flattened so that the peripheral edge portion 33 directly abuts the support wall 25 and provides a substantial welded surface area visible through the transparent lens members 30. Similarly, the dividing ribs 34 become substantially flattened as they are sealed to the underlying dividing portions 67 of the support walls 65. The tabs 37 are respectively adapted to be positioned within the tab openings 74 of the base 60 and serve to fix the position of the lens members 30 prior to welding. After welding, the lens members 30 cooperate with the associated support walls 65 to provide a plurality of hermetically sealed cells as described above.

It is an important feature of this invention that the dimensions of the molding openings 62 are such that none of the base walls 63, 64, 65, 68 or 69 has a thickness greater than 1/8 inch.

The purpose of this arrangement is to minimize molding time, since, in general, the molding time is proportional to the thickness of the members being molded. It has been found that a wall thickness of 1/8 inch corresponds to a molding time of approximately 30 seconds. This reduced molding time considerably reduces the cost of the manufacture of the base 60.

The road marker 50 may be installed on the road surface in the same manner as was described above with- respect to the marker 10, an adhesive pad 15 of impact-absorbing material being utilized.

The marker 50 is primarily intended to be used independently of any metal housing or casting, the inclined top surfaces 70 and 71 forming a crown above the height of the lens members 30 to provide additional reflective body area for reflecting daylight back to an observer. The metal cover plate 19 would of course not be used with the marker 50, which would preferably be used under non-snowplowable conditions. In a constructional model of the marker 50, the overall height of the marker, including the adhesive pad 15, is approximately .62 inches, the outer surface of the support walls 65 being inclined at approximately 41 to the surface of the road surface, so that the front face of each of the lens members 30 is inclined at an angle of approximately 45" to the horizontal.In use, the front edges of the ridges 45 of the lens members 30 lie in the same plane as the front edges of the shoulders 72 and 73 of the base 60, in effect defining a protective barrier for the front faces 31 of the lens members 30 in the marker 50.

Referring now also to Figures 13 through 15, 20 and 21, there is illustrated another embodiment of the road marker of the present invention, generally designated by tne numeral 100, and including the base 60 having mounted thereon two lens members, each generally designated by the numeral 80. Each of the lens members 80 is similar in construction to the lens member 30, with the exception that the lens members 80 are not provided with the outwardly extending protective ridges 45. More particularly, the len member 80 is formed of a light-transmitting synthetic resin and includes a substantially flat front face 31 and a rear face 32. As illustrated, the lens member 80 is generally rectangular and is intended to be positioned in the channel provided by the shoulders 72 and 73 and the support walls 65. The rear face 82 of the lens member 80 is provided with a peripheral edge portion 83 which extends about the entire periphery of the lens member 80 (Figure 15) and includes a portion 88 which is originally in the form of a generally triangular bead (Figures 20 and 21). The rear surface 82 further is provided with a plurality of dividing portions 84, the dividing portions 84 intersecting the peripheral edge portion 83 at equally-spaced distances therealong, thereby dividing the lens member 80 into a plurality of generally rectangular areas circumscribed by the peripheral edge portion 83 and the dividing portions 84. As illustrated, the dividing portions 84 originally may include a raised triangular sealing bead 89, and hereinafter, in the specification the dividing portions 84 may be referred to as "dividing ribs".

The lens member 80 is intended to be positioned over the inclined support wall 65 of the base 60 and rigidly secured thereto, preferably by ultrasonic welding. When properly positioned, each of the rectangular areas circumscribed by the peripheral edge portion 83 and dividing portions 84 will coextensively overlie and be in registry with the rectangularshaped openings of the recesses or pockets 66 formed in the support wall 65, while the dividing portions 84 will overlie the dividing portions 67 of the support wall 65.

When the lens member 80 is ultrasonically welded to the base 60, the sealing beads 88 and 89 become substantially flattened as a result of the energy imparted thereto during the ultrasonic welding process, whereby the peripheral edge portion 83 directly abuts the support wall 65, as best illustrated in Figure 19, and provides a substantial welded surface area visible through the transparent lens member 80. Similarly, the dividing ribs 84 will become substantially flattened as they are sealed to the underlying dividing portions 67 of the support wall 65. The lens member 80 also includes an outwardly extending tab 87 adapted to be positioned within the tab opening 74 on the base 60, and serves as a locator to fix the lens member 80 in position prior to welding.

After welding the lens member 80 to the base 60, each of the dividing wall portions 67 of the support wall 65, and the peripheral portion thereof, in cooperation with the dividing ribs 84 and peripheral edge portion 83, provide a plurality of hermetically sealed cells 85, each having a rectangular configuration when viewed in a direction normal to the front face 81.

The lens member 80 is provided with a retrodirective cube-corner-type reflector system to effect the signal function of reflecting light back to the driver of an oncoming vehicle whose headlights illuminate the road marker. As best seen in Figures 15 and 20, the rear face of the lens member 80, in those rectangular areas circumscribed by the dividing ribs 84 and the peripheral edge portion 83, is configured to provide a plurality of cube-corner-type retrodirective reflector elements 90. The retrodirective reflector elements 90 are diagrammatically illustrated in Figures 13 and 15 as a crisscross pattern of lines, but it will be appreciated that these reflector elements may be identical in construction to the reflector elements 40 described above in connection with the lens member 30 in Figures 8 and 9.

As seen in Figures 19 and 20, the apices of the cube-corner reflector elements 90 extend beyond the peripheral edge portion 83 and the dividing ribs 84, and into the cell 85, when the lens member 80 is secured to the base 60. Since the road marker 100 is intended primarily for use independently of a metal housing or casting in non-snowplowable applications, no protective ridges such as the ridges 45 of the lens members 30 are necessary in the lens members 80. But the abrasion resistance of the lens member 80 may be substantially increased by the provision of a layer 95 of protective material such as glass or the like overlying and adhered to the front face 81 of the lens member 80.Preferably, the glass layer 95 has a thickness of approximately .005 inches and is secured by a layer of suitable adhesive material of between about .006 and .012 inch thick to the front face 81 so as substantially to cover all of the portions of the front face 81 which overlie the retrodirective cube-corner reflector elements 90 of the lens member 80. It has been found that the use of this glass layer 95 has dramatically increased the abrasion resistance of the lens member 90, as is more fully explained in the aforementioned copending application 16861/77, Serial No. 1578834. The use of the glass overlay significantly reduces the degradation of the brightness of the lens member 80 as a result of normal wear in service.

Also, the arrangement of the lens member 80 with its peripheral transparent edge portion 83 and dividing ribs 84, and the underlying light-diffusing opaque support wall 65, imparts substantial daytime visibility to the marker 100, rendering it of greater utility than prior markers. The opaque, light-diffusing base 60 serves to reflect daylight impinging thereon to an observer and, at a distance, the uniform spacing of the dividing ribs 84 and dividing wall portions 67 causes the marker 100 to appear as a substantially uniform reflective body, with the cells 85 tending to disappear to the eye of the observer under daylight conditions.

The base 60 and the lens members 80 may respectively be constructed of any of the materials set forth above with respect to the base 20 and lens members 30, but preferably the base 60 and lens members 80 are both formed of a rubber-modified methyl methacrylate such as that sold under the trademark "PLEXIGLAS DR".

PLEXIGLAS DR. because it is rubber modified, gives higher impact resistance than unmodified Plexiglas; but reportedly it is a softer material than the unmodified Plexiglas.

Because of this, it was expected that PLEXIGLAS DR would not prove sufficiently abrasion resistant for use in road markers. Surprisingly, road markers of the character disclosed herein molded of PLEXIGLAS DR proved to be as abrasion resistant as those of unmodified Plexiglas.

Thus, the road markers of the present invention have very great daytime as well as nighttime visibility, as well as being substantially cheaper to manufacture than prior markers. This affords substantial advantages and economies in application of the markers.

More particularly, referring to Figure 22, there is illustrated a prior art arrangement of road markers as a lane marking on a roadway 110. This typical arrangement includes a combination of daytime and nighttime markers substantially equidistantly spaced apart, and arranged so that there are about four daytime markers 116 (such as the so-called "Botts Dots") or 117 (such as painted stripes) between every two nighttime markers 115. The nighttime markers 115 may, for example, be of the type of retrodirective reflector markers disclosed in the aforementioned U.S. Patent No. 3,332,327, which markers have a high nighttime visibility over a substantial distance and, therefore, can be widely separated on the road surface. But these prior art nighttime markers 115 have a relatively low daytime visibility.Therefore, the Botts Dots 116 or the painted stripes 117 are typically utilized at their normal spacings between the nighttime markers 115 to achieve the necessary visibility both in daylight and at night.

But the daytime visibility of the markers of the preset invention is so superior to that of the prior art markers 115 that they can be utilized effectively as both daytime and nighttime markers and can, therefore, be utilized in lieu of the prior type daytime markings at the normal marker spacings on the road surface, as illustrated in Figure 23. This offers several significant advantages. First of all, since only one type of road marker is utilized in this arrangement, only one type of application equipment need be used, thereby reducing the time and expense of installation. Moreover, fewer total markers for the same distance are needed~~four instead of five or eight instead of nine~~depending upon state requirements.

There are additional safety benefits, because the system of markers of the present invention requires no lane closures and requires less frequent installation than the prior art arrangement illustrated in Figure 22. Furthermore, the markers of the present invention have been found to have better daylight visibility in the rain than the painted lines 117 of the prior art systems. Finally, the system has added safety benefits over present installations because the same pattern of reflected signals appears to the motorist under day and night driving conditions.

The above detailed description is provided by way of example only. Various details of design and construction may be modified without departing from the scope of the invention as defined in the appended claims.

WHAT WE CLAIM IS: 1. A reflex reflector incorporating a base member and a transparent light transmitting lens member supported thereon, wherein said base member includes a support surface having a plurality of isolated open pockets therein with portions of said support surface surrounding each said pocket and wherein said lens member is a one piece member extending over substantially all of the pocket opening and has a rear face provided with a plurality of discrete groups of reflex-reflecting elements and a front face, said lens member being affixed to said base member with portions of said rear face between the discrete groups in contact with the pocket surrounding portions of said support surface and each of said groups of relex-reflecting elements located in a corresponding one of said pockets to form a plurality of discrete reflex reflector zones capable of reflecting light emanating from a source and impinging upon said front face of said lens member back toward the light source.

2. A reflector according to claim 1, wherein said reflex-reflecting elements are of the cube-corner type.

3. A reflector according to claim 2, wherein each of said discrete groups of cube-corner elements substantially completely fills one of said pockets.

4. A reflector according to any of claims 1 to 3, wherein said base member is formed of an opaque, light-diffusing synthetic resin and wherein the areas of said base member covered by said transparent lens member not occupied by said reflex-reflecting elements reflect daylight impinging upon the front face of said lens member.

5. A reflector according to any of claims 1 to 4, wherein said lens member is hermetically sealed to said support surface around each pocket opening, whereby each of said groups of said reflex-reflecting elements is located in a hermetically sealed cell.

6. A reflector according to any preceding claim, wherein at least one of said base member and said lens member is formed of a rubber-modified methyl methacrylate material.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. unmodified Plexiglas; but reportedly it is a softer material than the unmodified Plexiglas. Because of this, it was expected that PLEXIGLAS DR would not prove sufficiently abrasion resistant for use in road markers. Surprisingly, road markers of the character disclosed herein molded of PLEXIGLAS DR proved to be as abrasion resistant as those of unmodified Plexiglas. Thus, the road markers of the present invention have very great daytime as well as nighttime visibility, as well as being substantially cheaper to manufacture than prior markers. This affords substantial advantages and economies in application of the markers. More particularly, referring to Figure 22, there is illustrated a prior art arrangement of road markers as a lane marking on a roadway 110. This typical arrangement includes a combination of daytime and nighttime markers substantially equidistantly spaced apart, and arranged so that there are about four daytime markers 116 (such as the so-called "Botts Dots") or 117 (such as painted stripes) between every two nighttime markers 115. The nighttime markers 115 may, for example, be of the type of retrodirective reflector markers disclosed in the aforementioned U.S. Patent No. 3,332,327, which markers have a high nighttime visibility over a substantial distance and, therefore, can be widely separated on the road surface. But these prior art nighttime markers 115 have a relatively low daytime visibility.Therefore, the Botts Dots 116 or the painted stripes 117 are typically utilized at their normal spacings between the nighttime markers 115 to achieve the necessary visibility both in daylight and at night. But the daytime visibility of the markers of the preset invention is so superior to that of the prior art markers 115 that they can be utilized effectively as both daytime and nighttime markers and can, therefore, be utilized in lieu of the prior type daytime markings at the normal marker spacings on the road surface, as illustrated in Figure 23. This offers several significant advantages. First of all, since only one type of road marker is utilized in this arrangement, only one type of application equipment need be used, thereby reducing the time and expense of installation. Moreover, fewer total markers for the same distance are needed~~four instead of five or eight instead of nine~~depending upon state requirements. There are additional safety benefits, because the system of markers of the present invention requires no lane closures and requires less frequent installation than the prior art arrangement illustrated in Figure 22. Furthermore, the markers of the present invention have been found to have better daylight visibility in the rain than the painted lines 117 of the prior art systems. Finally, the system has added safety benefits over present installations because the same pattern of reflected signals appears to the motorist under day and night driving conditions. The above detailed description is provided by way of example only. Various details of design and construction may be modified without departing from the scope of the invention as defined in the appended claims. WHAT WE CLAIM IS:

1. A reflex reflector incorporating a base member and a transparent light transmitting lens member supported thereon, wherein said base member includes a support surface having a plurality of isolated open pockets therein with portions of said support surface surrounding each said pocket and wherein said lens member is a one piece member extending over substantially all of the pocket opening and has a rear face provided with a plurality of discrete groups of reflex-reflecting elements and a front face, said lens member being affixed to said base member with portions of said rear face between the discrete groups in contact with the pocket surrounding portions of said support surface and each of said groups of relex-reflecting elements located in a corresponding one of said pockets to form a plurality of discrete reflex reflector zones capable of reflecting light emanating from a source and impinging upon said front face of said lens member back toward the light source.

7. A road marker comprising a reflex reflector, said reflex reflector incorporating a

base member and a transparent light transmitting lens member supported thereon, wherein said base member includes a support surface having a plurality of isolated open pockets therein with portions of said support surface surrounding each said pocket and wherein said lens member is a one piece member extending over substantially all of the pocket openings and has a rear face provided with a plurality of discrete groups of reflex-reflecting elements and a front face, said lens member being affixed to said base member with portions of said rear face between the discrete groups in contact with the pocket surrounding portions of said support surface and each of said groups of reflex-reflecting elements located in a corresponding one of said pockets to form a plurality of discrete reflex reflector zones capable of reflecting light emanating from a source and impinging upon said front face of said lens member back toward the light source.

8. A road marker according to claim 7, wherein said base member has a bottom surface and said front face of said lens member is generally planar and is so oriented as to make an acute angle of between 15 and 60 with said bottom surface.

9. A road marker according to claim 8, wherein an adhesive impact-absorbing material is secured to said bottom surface for fixedly securing said road marker to an underlying support surface.

10. A reflex reflector substantially as hereinbefore described with reference to the embodiments illustrated in the accompanying drawings.

11. A road marker substantially as hereinbefore described with reference to the embodiments illustrated in the accompanying drawings.