EP0891451A1

EP0891451A1 - A light reflecting surface structure

Info

Publication number: EP0891451A1
Application number: EP97917284A
Authority: EP
Inventors: Gert A. Mikkelsen
Original assignee: Gert Mikkelsen APS
Current assignee: Gert Mikkelsen APS
Priority date: 1996-04-10
Filing date: 1997-04-10
Publication date: 1999-01-20
Also published as: WO1997038170A1; AU2568297A

Abstract

A light reflecting surface structure for reflecting light beams from for instance vehicular traffic along a roadway, the structure comprising protuberances (35) arranged individually or in an array. The protuberances have at least two reflective surface portions (40, 41, 42) having different angles with respect to a given direction (37) and thus with respect to a given light beam (36). Further reflective surface portions having different angles with respect to a plane of the subsurface for the surface structure may also be incorporated in a protuberance (35). The protuberances (35) are either discrete protuberance inserts or integral protuberance configurations of a surface layer on the subsurface. The surface structure is also intended for application to kerb stones, paving stones, highway barriers, billboards, stadium advertising signs and the like.

Description

A LIGHT REFLECTING SURFACE STRUCTURE

This invention relates to a light reflecting surface structure for regulating or otherwise cooperating with vehicular traffic and for other applications such as advertising signs, the structure comprising a base means for adherence to or being integral with or being constituted by a subsurface such as a road pave¬ ment, road kerb, road barrier strip, road sign or the like, the base means being provided with one or more protuberances each having at least two reflective surface portions.

In connection with nocturnal traffic, particularly along a non-illuminated road¬ way, it is of great value for traffic security that light beams from the headlights of the vehicles be retroreflected to the drivers from markings on the road pavement, kerb, signs, road barrier strips and the like. The traffic regulating retroreflections should be clearly visible for different angles of incident light with respect to the markings, i.e. both when a vehicle is relatively far away and the vertical angle with respect to the plane of the subsurface is relatively small and when the vehicle is relatively close and the angle is relatively large.

Furthermore, it is also important that the light beams be retroreflected with high intensity for different angles of approach of the vehicles to the markings, i.e. for different horizontal angles of the light beams with respect to a plane perpendicular to the plane of the subsurface.

Therefore, it is a main object of the invention to provide a light reflecting surface structure that may reflect light beams having different angles of incidence on the markings, and according to the invention this is achieved by the protuberances each having at least two reflective surface portions arranged at different angles with respect to a direction of light beams from for instance vehicular traffic, the at least two surface portions being arranged such that they are able to retroreflect light beams for instance emitted by the vehicular traffic.

So as to ensure as continuous a retroreflection as possible as the vehicle approaches the marking, the at least two reflective surface portions may have different angles with respect to the plane of the subsurface. The protuberances may thus have a series of surface portions with such different angles, or the surface portions may constitute a curved surface having a gradually varying angle with respect to said plane.

So as to ensure good retroreflection if the vehicles approach the marking from different directions, the at least two reflective surface portions may have different angles with respect to a plane perpendicular to the plane of the sub¬ surface. The protuberances may thus have a series of reflective surface portions with such different angles, or the surface portions may constitute a curved surface having a gradually varying angle with respect to said perpendicular plane.

According to the invention, the base means may be constituted by a layer of curable material applied to the subsurface for adherence thereto, the protuberances being formed in the curable layer in connection with or after said application but before final curing of the curable material. Particularly in connection with markings on road pavements this affords a simple and practical embodiment of the invention allowing markings to be applied quickly and efficiently.

In another embodiment of the invention, the base means may be constituted by sheet material, the protuberances being integral with and formed in one surface of said sheet material. Hereby, the markings may be produced under controlled conditions for achieving a high quality control which may be important in connection with particularly complicated shapes and distribution patterns of the protuberances.

In many cases the roadway may comprise paving stones or kerb stones of, for instance concrete, and even though application of the base means may take place by applying and curing a layer of curable material or affixing sheet material to the surface of the concrete, in many cases it is advantageous that the base means be a surface layer of the kerb stone or the paving stone, the protuberances being integral with and formed in said surface layer. Hereby, the base layer may be formed during the moulding of the stones themselves in the vibration moulds.

In the case of road signs, road barrier strips and the like, the metallic sheet metal of same may be deformed to form the protuberances, but preferably the base means is constituted by a surface layer of a metallic sheet for the road barrier strip or the road sign, the protuberances being integral with and formed in said surface layer.

The reflective surface portions may naturally have varying angles with respect to both of the mentioned planes, the respective surface portions thus serving a dual purpose with respect to the direction of the light beams to be retroreflected.

In some applications it is desirable that the resistance to wear and tear and the quality of the reflection of the reflective surface portions be high and therefore it is advantageous that at least one of the protuberances is constituted by a separate protuberance insert for being embedded in or affixed to a surface of the base means. The protuberance insert according to the invention may be manufactured in different manners according to the material employed and the size and re¬ flective qualities required for the reflective surface portions.

In cases where the protuberance insert is to be applied in connection with a layer of curable material it is advantageous that the protuberance insert is constituted by a substantially circular, hollow, substantially dome shaped body having an annular flange for being inserted in a curable material layer, the lateral slopes of the dome shaped body being provided with the reflective surface portions. Here- by an insert is obtained that is simple to place in the curable layer before or after curing of same.

In cases where the protuberance insert is to be applied in connection with a hard surface, it is advantageous that the protuberance insert is constituted by a sub- stantially circular, solid, substantially dome shaped body having a planar surface for abutting the surface of for instance a kerb stone, the lateral slopes of the dome shaped body being provided with the reflective surface portions. Hereby an insert is obtained that either may be glued to or embedded in for instance concrete.

Preferably, the protuberance insert is made of a material such as surgical stain¬ less steel or high density ceramics having a good resistance against surface damage and good light reflection properties.

The protuberances may be arranged so far from each other that they do not create shadows for each other for the relevant directions of the light beams to be retroreflected, but preferably the height of the protuberances above the surface of the base means and/or the distance between protuberances is chosen such that at least some of the reflective surface portions of a protuberance is not in the shadow of other protuberances for relevant light beams.

In many applications it is useful if the image formed by the retroreflected light may change for different angles of incidence of the light beams and therefore according to the invention, the reflective surface portions may be distributed such within an array of the protuberances that at least two different visual images are produced by the retroreflection of the light beams for different angles of the light beams relative to the plane of the subsurface and/or relative to a plane perpendicular to said plane.

In many applications it is useful that the image formed by the retroreflected light beams contains information as regards zones directions and so on, and according to the invention this may be obtained by one or more of the reflective surface portions of one or more of the protuberances having a different colour than the rest of said reflective surface portions. Hereby, symbols and area demarcations may be indicated by colour variations in the formed image. Furthermore, the possibility of creating different visual images for a given viewer in a sign is enhanced hereby.

Advantageously the surface portions having different colours may be distributed such within an array of the protuberances that at least two different visual images are produced by the retroreflection of the light beams for different angles of the light beams relative to the plane of the subsurface and/or relative to a plane perpendicular to said plane. Hereby different information may be given regarding the route of travel depending on the direction of travel and/or the position of the vehicles with respect to the markings. Arrows may appear in the midst of the array to indicate a certain direction and so on. On a sign different images may be created for a given viewer.

So as to achieve an efficient run-off of rain water and melted snow it is advantageous in case the subsurface is substantially horizontal, that the thickness of the layer of curable material decrease towards one or more edges of the area of subsurface covered by the curable material.

Advantageously, at least one protuberance may be arranged in a recess in the surface of a kerb stone or a paving stone, said recess having a shape allowing light beams emitted by vehicular traffic to be retroreflected. Hereby the insert may be protected from being scraped off by for instance a sweeping device or a snowplow while still being operational for all relevant light beams from the vehicular traffic.

A particularly advantageous and economically as well as designwise attractive solution is obtained according to the invention by a kerb stone at at least one end thereof being provided with a recess for receiving a pivoting element for allowing two adjacent kerb stones to be mutually joined in a substantially horizontally pivotable manner. Hereby one standard kerb stone may be used to create a wide range of curves in the boundary of a sidewalk or highway.

Advantageously, the kerb stone may at at least one end thereof be provided with a pivoting element integral therewith and at least one protuberance may be arranged on the surface or in a recess in the surface of the pivoting element. Furthermore, the pivoting element may have a substantially circular cylindrical surface.

This invention also relates to a method for producing a light reflecting surface structure, the method comprising the steps of:

- preparing a viscous, curable material having good Iight reflecting properties in cured condition,

spreading the material in a substantially even layer on a subsurface,

- applying a moulding means to the surface of said layer for moulding the protuberances in said surface, and

- curing the layer of curable material.

Hereby, a particularly simple and efficient method is achieved for applying a coating according to the invention to an existing road pavement and the like.

Advantageously, the curable material may be prepared in portions with at least two different colours in cured condition, the differently coloured portions being distributed on different areas of the subsurface for achieving the desired distribution of differently coloured reflective surface portions.

This invention furthermore relates to a kerb stone, a pivoting element, a paving stone, a road sign, a road barrier strip and an advertising billboard, all having a light reflecting surface having the features defined in any of the relevant appended claims.

Furthermore, the invention relates to a kerb stone having a recess for cooperation with a pivoting element.

The invention will now be explained more in detail in connection with several embodiments of the surface or surface coating, protuberances and kerb stones according to the invention shown by way of example only in the accompanying drawings, where

Figs. 1 and 2 diagrammatically illustrate, in a top view and a side elevational view, respectively, the utilization of retroreflection for regulating vehicular traffic,

Fig. 3 shows a top view of a traffic stripe according to the invention on a road pavement and a cross section of the stripe along line A-A,

Figs. 4-7 show partial cross sections of different embodiments of a protuberance according to the invention,

Figs. 8-9 show partial cross section through further embodiments of the protuberances according to the invention,

Figs. 10-11 show top views of part of an array of embodiments of the surface coating according to the invention,

Fig. 12 shows a partial vertical sectional view and a corresponding front elevational view of a first embodiment of a kerb stone according to the invention,

Fig. 13 shows a partial horizontal sectional view of a second embodiment of a kerb stone according to the invention,

Fig. 14 shows a front view of a section of a surface coating of a third embodi¬ ment of a kerb stone according to the invention,

Fig. 15 shows a partial vertical sectional view of the embodiment of Fig. 14,

Fig. 16 shows a partial horizontal sectional view of a fifth embodiment of a kerb stone according to the invention,

Figs. 17 - 19 show a top planar view, an elevational view and a vertical cross sectional view, respectively, of a first embodiment of a protuberance insert according to the invention,

Figs. 20-22 show views corresponding to Figs. 17-19 for a second embodiment of a protuberance insert according to the invention,

Figs. 23-25 show top planar views of three embodiments of a longitudinal highway marking according to the invention comprising protuberance inserts according to the invention,

Figs. 26-27 show a vertical sectional view of a protuberance insert according to Fig. 22 and 19, respectively embedded in a highway marking according to any of the Figs. 23-25,

Figs. 28-30 show a front elevational view, a top planar view and a vertical cross sectional view, respectively, of a first embodiment of a sidewalk kerb stone of for instance concrete with protuberances according to the invention integrally moulded into the surface of the kerb stone,

Figs. 31-33 show views corresponding to Figs. 28-30 of a second embodiment of a highway shoulder kerb stone with moulded protuberances according to the invention,

Figs. 34-36 show views corresponding to Figs. 28-30 of a third embodiment of a highway shoulder kerb stone with embedded protuberance inserts according to the invention arranged in recesses, the kerb stone being associated with a cooperating pivoting element according to the invention,

Figs. 37-39 show views corresponding to Figs. 34-36 of a fourth embodiment of a sidewalk kerb stone similar to the one shown in Figs. 34-36,

Figs. 40-42 and 43-45 show enlarged view of the recess with an embedded protuberance of Figs. 34-36 and Figs. 37-39, respectively,

Fig. 46 shows various arrangements of straight kerb stones with pivoting elements according to the invention corresponding to different values of the radii of curvature of for instance a highway shoulder,

Fig. 47 shows different shapes of straight and curved kerb stones according to the invention with pivoting elements according to the invention,

Fig. 48 shows different combinations of various kerb stones according to the invention with pivoting elements according to the invention,

Figs. 49-51 show a top planar view, a front elevational view and a vertical cross section, respectively, of an embodiment of a highway shoulder kerb stone with an integral pivoting element and a discrete protuberance insert glued to the kerb stone in a recess in same, and

Figs. 52-53 show a top planar view and a front elevational view, respectively, of an embodiment of a highway shoulder kerb stone with recesses at either end for receiving a discrete pivoting element having a protuberance insert glued to the top surface thereof.

Referring now to Figs. 1 and 2, a driver 1 of a truck and a driver 2 of a passenger car are located in a typical relationship to headlights 3 and 4 of the truck and car, respectively. At the left side of Figs. 1 and 2 the short distance light beams 5, 6 and 7 are shown impinging on protuberances with reflective surface portions according to the invention at points 8 and 9 a short distance S (e.g. 5m) in front of the vehicles. The beams 5-7 are retroreflected to the eyes of the drivers 1 and 2 in the form of reflected beams 10, 1 1 and 12, respective¬ ly. At the right side of Figs. 1 and 2, the long distance light beams 13 and 14 are shown impinging on protuberances at points 15 and 16 a long distance L (e.g. 60m) in front of the vehicles. The beams 13 and 14 are retroreflected to the eyes of the drivers 1 and 2 in the form of reflected beams 17 and 18, respectively.

The capability of reflecting light beams 5-7 and 13-14 and all intermediary light beams is of great value for the efficient functioning of the traffic regulating markings, and this capability is greatly enhanced by providing the protuberances with reflective surface portions at different angles relative to the pavement and the vertical plane as described in the following with relation to Figs. 4-11.

It will be appreciated that the traffic regulating reflection capability of kerb stones, road signs, road barrier strips, pavement stones and so on may be illustrated in much the same manner, thereby illustrating the beneficial effect of the differently oriented surface portions according to the invention in relation to such elements of a roadway configuration.

Referring now to Fig. 3, a road paving strip constituted by a surface layer 19 according to the invention and comprising protuberances 20 arranged in an array, has a thickness that diminishes from the centreline of the strip towards the longitudinal edges thereof, thereby achieving an efficient water run-off gradient for avoiding impairment of the reflective capability by rain water accumulated on the strip.

The four embodiments of a protuberance according to the invention shown in Figs. 4-7 are all shown in a greatly enlarged scale. The base layer 21 which may, for instance, be a coating applied to a subsurface, an outer layer of the subsurface, sheet material to be affixed to the subsurface or sheet material to form a sign or barrier strip, is provided with protuberances 22 arranged in an array (not shown).

In Fig. 4 the protuberance 22 has a flank 23 comprising two substantially planar surface portions 24 and 25 at an angle of 80° and 73.5°, respectively, with respect to the plane 26 of the subsurface and thereby having a reflecting angle of 10° and 16.5° with respect to the plane 26. The surface portions 24 and 25 thereby allow the flank 23 to reflect variable angle incoming light beams from vehicular traffic much better over the relevant travel distance of the vehicles than a flank having the same inclination along the entire area thereof.

In Fig. 5, the protuberance 27 is higher than the protuberance 22 of Fig. 4 to accommodate a further substantially planar reflective surface portion 28 above the surface portions 24 and 25, said surface portion 28 having a reflecting angle of 3.5° with respect to the plane 26 thereby enabling the flank 23 to retroreflect light beams having a smaller angle with respect to the plane 26, i.e. light beams emitted by a vehicle relatively far from the point at which the corresponding protuberance 27 is located.

In Figs. 6 and 7 two protuberances 29 and 30, respectively, are shown, the protuberance 29 being lower than the protuberance 30. Both the protuberances 29 and 30 have reflective flanks 31 comprising a convexly curved surface having portions with reflective angles with respect to the plane 26 continuously varying from 20° to 7° in the case of protuberance 29 and from 20° to 0° in the case of protuberance 30. In these embodiments the light beams with different angles of incidence are retroreflected with a gradual change in intensity owing to the curved shape of the flange 31 , in principle constituted by an infinite number of surface portions having different reflective angles.

In Figs. 8 and 9 arrangements of low and a high protuberances 22, 27 and 29, 30, respectively, are illustrated, where an array of protuberances contains sequential rows of low ones 23, 29, respectively, and high ones 27, 30, respectively, so that light beams 32 having a small angle (eg. 3.5°) with respect to the plane 26 will be reflected by every second row containing the high protuberances because the low ones do not block the light beam 32. The light beams 33 and 34 will be reflected from both rows of protuberances as they are not blocked by any of the other protuberances.

This effect of not blocking the small angle light beams may also be obtained by dispersing the protuberances to a greater degree but this will entail a lower ratio of retroreflected light because of the smaller density of protuberances per unit of area.

Referring now to Fig. 10, a section of an array of protuberances 35 is shown in a view towards the subsurface on which the surface structure or coating is arranged, for instance a road pavement. Incoming light beams 36 having different angles with respect to the subsurface and different angles with respect to a main direction 37, for instance the centreline of the roadway, impinge on the protuberances 35 having substantially planar surface portions 40, 41 and 42 having a reflecting angle with respect to the direction 37 of 35.5°, 13.5° and 4.5°, respectively.

Hereby the protuberances 35 may retroreflect light beams having varying angles with respect to a direction parallel to the subsurface that depend on the position of a vehicle with respect to the relevant protuberance.

The surface portions 40, 41 and 42 may have the same reflecting angle with respect to the subsurface, or said angles may vary according to the application.

The surface portions 40-42 each constitute a part or a facet of a segment com- prising one or more additional surface portions or facets having angles with re¬ spect to the subsurface different from the corresponding angles of the portions 40-42 in a manner very similar to the embodiments described in connection with Fig. 4 and 5.

The reflective surface portions or facets of this embodiment will, in the case of a coating of a road pavement, retroreflect light beams from a vehicle travelling along the road with high intensity even though the position of the vehicle changes with relation to the individual protuberances 35.

The protuberances 35 may be of different height as described in connection with Fig. 9 so as to avoid shadows for the small angle light beams.

Referring now to Fig. 11 , a section of an array of protuberances 43 is shown in a view towards the subsurface on which the surface structure or coating is arranged, for instance a road pavement. Incoming light beams between the beam 45 and the beam 46 having angles between 18° and 0° with respect to a main direction 47, for instance the centreline of the roadway, impinge on the protuberances 43 having curved surface portions 44 or flanks much in the same manner as the embodiments shown in Figs. 6 and 7.

The same effect is obtained as in the embodiment of Fig. 10 as in fact the number of facets or reflective surface portions having different angles with re- spect to the direction 47 and the subsurface is in principle infinite.

Referring now to Fig. 12, a kerb stone 50 of concrete or the like is arranged between a road pavement 51 and a sidewalk 52 in the usual manner. The ex- posed face 53 and top surface 54 of the kerb stone 50 are provided with protuberances 55 having reflective surface portions with different reflective angles with respect to the plane of the road surface and/or a plane perpendicular to same.

The projections may be formed during the moulding process of the kerb stones in a surface layer of reflective material or they may be formed in a layer of suit¬ able reflective material applied to the surface of the kerb stone after the moulding process. Paving stones for arrangement in the surface of a road, a sidewalk or the like may have a very similar configuration according to the invention.

In Fig. 13 there is shown a horizontal section of the surface region of a kerb stone 56 of for instance concrete having protuberances 57 and 58 of different lengths and having curved flanks 59 and 60 in manner very similar to the protu- berances of the embodiment shown in Fig. 7 and 8, the reflective angles of the infinite numbers of surface portions constituting the flank 60 with respect to the centreline of the roadway varying from 0° to 18°.

Fig. 16 shows a view very similar to Fig. 13, the flanks 62 and 63 being con- stituted by two or three surface portions having reflective angles of 3.5°, 10° and 16.5° with respect to the centreline of the roadway in a manner very similar to the embodiment shown in Figs. 4, 5 and 8.

Referring now to Figs. 14 and 15 showing a front elevational view and a vertical sectional view, respectively, a kerb stone 70 has on its surface tongue-like protuberances 71 provided with flanks 72 that either may be provided with separate reflective facets with varying reflective angles or with a continuously curved surface in principle constituted by an infinite number of such facets.

When the surface structure according to the invention comprises a layer of cur¬ able plastic material, the layer is first applied to the region of the subsurface to be covered well within the boundaries of same, and thereafter a die, for instance mounted on the circumferential surface of a roller, is utilized to distribute the layer across said region by means of pressure. The die may have a concave shape for varying the thickness of the layer as for instance shown in Fig. 3. The die may have means to shape the protuberances in the curable material while spreading it by pressure thereon, or a different die or other means may by used after such spreading to shape the protuberances.

The surfaces of the die may be coated with a layer of low friction material such as Teflon to allow moulding relatively small protuberances as thereby the tendency of the curable material to stick to the die is reduced. This tendency may also be reduced in other ways, e.g. by applying a lubricant or other release agent intermittently or continuously to the die.

Referring now to Figs. 17-19, a protuberance insert having a dome like body 73 with an annular flange 74 and slopes 75 provided with reflective surface portions 76 is embedded in a layer 78 of curable material adhered to a subsurface such as road asphalt. The insert is anchored in the layer 78 by friction and adhesion with respect to the flange 74 at surface portions 77 thereof. The embedding depth is controlled by the horizontal portion 79 between the dome 73 and the flange 74 as the resistance against downward movement into the layer 78 greatly increases when the portion 79 abuts the top of the layer 78. Adhesion forces between the underside of the portion 79 and the layer 78 will also add to the anchoring effect.

Referring now to Figs. 20-22, a solid, dome like body 80 having reflective sur¬ face portions 81 and a planar bottom surface is intended for being arranged on a hard surface for by means of a suitable adhesive. The body 80 may be cut vertically into two or more pieces before being glued to the surface such as a kerb stone, a road barrier or a road sign.

The shape of the inserts may naturally vary widely and may also have con¬ tinuously and smoothly varying angles instead of facets as illustrated analogous with the embodiment of Figs. 6-8. The insert may in fact be spherical or semi- spherical. The material of the inserts should preferably be of a type with high re- sistance to wear and tear and with a relatively high ability to reflect light including being suitable for forming smooth surfaces by inexpensive means. Suitable materials are aluminium oxide or porcelain as well as surgical grade stainless steel. Tough glass materials will also be suitable for some applications.

Referring now to Figs. 23-25, three different ways of deploying a protuberance insert 73 or 80 on a highway are shown, where the inserts are embedded in or glued on discrete regions 83 covered by curable material, in a combination of discrete regions 84 covered by curable material and a continuous, conventional road stripe marking 85 and in or on a continuous strip of curable material 86, respectively.

In Figs. 26 and 27 a vertical sectional view of an insert 73 and 80, respectively, embedded in or glued on any of the regions 83, 84 or 86 are shown. So as to protect the insert against being scraped away by snowplows or sweeping devices and similar devices, the region 85 may be higher than the top of the insert so that a snowplow or such device is prevented from engaging the insert 73 or 80. In a similar manner the discrete regions 83 and 85 may have portions with a larger height to achieve the same aim. The object of protecting the inserts against being scraped away may also be achieved by other deflecting means arranged in the roadway or in the curable material, provided no detrimental shadowing effect is thereby introduced. Naturally, the individual inserts shown in Figs. 23-25 may be supplemented by more inserts to form an array analogous to the array indicated in Fig. 2.

Referring now to Figs. 28-30 and 31-33, a sidewalk kerb stone 87 and a highway shoulder kerb stone 97, respectively, are shown having faceted protuberances 88, 98 moulded in the surface of the concrete kerb stones either in the concrete of the kerb stone itself or in a special surface layer of the kerb stones of a material with particularly good moulding properties and light reflect¬ ing properties, such as a fine grained special white concrete or some other material suited for application in a moulding process for the kerb stones. The kerb stones have cylindrical recesses 89, 99 for receiving a pivoting element as shown in Fig. 35 for rotatably joining the kerb stones to one another to allow formation of curved sections of kerb with one standard kerb stone and a standard pivoting element as illustrated in Fig. 46. The pivoting element may be integral with the kerb stone at one end thereof as illustrated in Fig. 48.

Referring now to Figs 34-36 together with Figs. 40-42 and Figs. 37-39 together with Figs. 43-45, a highway shoulder kerb stone 90 and a sidewalk kerb stone 100, respectively, are shown having recesses 91 , 101 , wherein protuberance inserts 80a (half an insert 80 of Fig. 20) are glued to the surface of the kerb stone, the inserts 80a thereby being protected from being removed by devices moving along the surface of the kerb stones. The recesses 91 , 101 are shaped such that light beams from highway traffic are not prevented from impinging on the inserts 80a.

The kerb stones 90, 100 have cylindrical recesses 92, 102 at either end for re¬ ceiving correspondingly cylindrical pivoting elements 93 for pivotably joining adjacent kerb stones to one another as described above.

Referring now to Fig. 46, different combinations of kerb stones 87, 97, 90 and 100 with pivoting elements 93 for attaining various radii of curvature for side¬ walk kerbs and highway should kerbs, respectively, are illustrated. It will be appreciated that a wide range of curvatures may be complied with utilizing one standard kerb stone and one standard pivoting element, a factor of great im¬ portance in the pricing of such solutions.

In Fig. 47 a set of standard kerb stones with integral pivoting elements compris- ing a straight kerb stone 110, and four curved kerb stones 111-114 are illustrated. In Fig. 48 various curvature situations are illustrated solved by using the set of kerb stones shown in Fig. 47.

Referring now to Figs. 49-51 , a highway shoulder kerb stone 120 having a cylindrical recess 121 at one end and an integral, substantially cylindrical pivot¬ ing element 122 at the opposite end for being pivotably received in the recess 121 of an adjoining kerb stone 121 is provided with recesses 123 in which protuberance inserts 80a are glued to the surface of the kerb stone 120.

Referring finally to Figs. 52-53, a highway shoulder kerb stone 130 is shown having a cylindrical recess 131 at either end for receiving a cylindrical pivoting element 132 for pivotably joining two kerb stones 130 together. The pivoting element 132 is provided with a protuberance insert 80 at the top thereof. The protuberance insert may naturally be received in a recess at the top of the element 132 in a manner similar to the recesses 123 in Figs. 49-51. The insert may also be arranged on the cylindrical surface of the element 132 in a similar recess. Naturally, the pivoting element may have a number of other con- figurations and may be received in the kerb stones in a number of different ways, for instance a rod of steel received in suitable sockets or apertures in the kerb stones.

Although several embodiments of the light reflecting surface structure according to the invention have been explained in detail, various modifications, amend¬ ments and variations as well as other applications are contemplated by the inventor and others are obvious to those skilled in art without departing from the scope of the invention as defined in the appended claims.

Thus, the protuberances of an array may have two or more colours so that for instance an arrow in one colour may appear within an area of another colour. The orientation of the reflective surface portions on the protuberances may also be different from region to region of the area so that the image produced by the retroreflection seems to change or move when the source of the light beams moves in relation to the area covered by the surface coating.

The protuberances being separate elements and having reflective surfaces and being embedded or otherwise affixed to the subsurface or a coating on said sub- surface may for instance be glass or metallic prisms or bodies and they may be covered by a protective transparent plastic film after being affixed to or embedded in the surface coating or the subsurface. The plastic film may have the object of protecting the desirable smoothness of the reflective surface por¬ tions against wear and tear. The surface portions of each separate element such as a metallic or glass body used as a protuberance may have different colours so that the image variation capability in connection with moving light sources is greatly enhanced.

The principles of the invention are in fact envisioned by the inventor to be applied to any surface illuminated by a mobile light source, alternatively where the viewer moves in relation to the surface and the light source, alternatively where the subsurface is moved or pivoted in relation to the view and/or the re¬ flected light source and other analogous situations where different optical effects are desired obtained with the same physical structure.

The protuberances may have any shape suitable for the purpose and may be constituted by ridges, wave-like projections, steps, shoulders and so on as long as the provision of reflective surface portions with different reflective angles with respect to the subsurface and/or a plane normal to the subsurface is allowed. Thus, they may for instance be incoφorated in the conventional pro¬ filed audio warning stripes for creating noise signals from a vehicle tyre rolling on the stripe.

The protuberances may be formed by deformation of the sheet metal of a sign or barrier strip. The base layer may be constituted by plastic or metal sheets to be placed temporarily, for instance by adherence, on signs, barrier strips and road- ways to indicate, for instance, temporary traffic rerouting and the like in con¬ nection with repairs and the like. In the latter case the protuberances may be bodies having reflecting surface portions of a very high quality for particularly good reflection of light beams as such sheets may be reused many times and the requirements to retroreflection in such applications are particularly strict.

A particularly useful application is in advertising signs for for instance sports stadiums where several images are desired incorporated in one sign, the images being changed for a given viewer by altering the angle of incidence of the light source so that different facets of the protuberances having different colours and distribution patterns are brought into the reflection zone for the viewer thereby creating a new and different image for the viewer.

This effect may also be obtained by arranging the sign such that for a given illumination of the sign it may be pivoted around an axis in the plane of the sign or around two orthogonal axes in said plane and further around an axis orthogonal to the plane of the sign. Thereby, different facets of the protuberances in a given array on the sign and having different colours will become visible to the viewer while other facets will disappear from view. The effect can also be obtained by flexing the sign in various manners, for instance flexing the sign to form a cylindrical surface or applying a localized force to flex part of the surface. Several such signs may be arranged adjacent each other and rotated and flexed individually so that the total image created by the several adjacent signs may be varied in an even greater number of ways. A combination of moving the light source and such rotation and flexing will also increase the image variation possibilities.

The number of "pixels" thus at hand for the various images will depend on the size (and number and mutual proximity) of the protuberances and the number and distribution of as well as the number of different colours of the facets of each protuberance in the array.

Claims

1. A light reflecting surface structure for regulating or otherwise cooperating with vehicular traffic and other similar applications, the structure comprising a base means for adherence to or being integral with or being constituted by a sub¬ surface such as a road pavement, road kerb, road barrier strip, road sign or the like, the base means being provided with one or more protuberances each having at least two reflective surface portions arranged at different angles with respect to a direction of light beams from for instance vehicular traffic, the at least two surface portions being arranged such that they are able to retroreflect light beams for instance emitted by the vehicular traffic.

2. A surface structure according to claim 1 , wherein the at least two reflective surface portions have different angles with respect to the plane of the sub- surface.

3. A surface structure according to claim 1 or 2, wherein the at least two re¬ flective surface portions have different angles with respect to a plane perpendi¬ cular to the plane of the subsurface.

4. A surface structure according to any of the claims 1-3, wherein the base means is constituted by a layer of curable material applied to the subsurface for adherence thereto, the protuberances being formed in the curable layer in connection with or after said application but before final curing of the curable material.

5. A surface structure according to any of the claims 1-3, wherein the base means is constituted by sheet material, the protuberances being integral with and formed in one surface of said sheet material.

6. A surface structure according any of the claims 1-3, wherein the base means is constituted by a surface layer of a kerb stone or a paving stone, the protuberances being integral with and formed in said surface layer.

7. A surface structure according to any of the claims 1-3, wherein the base means is constituted by a surface layer of a metallic sheet for a road barrier strip or a road sign, the protuberances being integral with and formed in said surface layer.

8. A surface structure according to any of the preceding claims, wherein at least one of the protuberances is constituted by a separate protuberance insert for being embedded in or affixed to a surface of the base means.

9. A surface structure according to claim 8, wherein the protuberance insert is constituted by a substantially circular, hollow, substantially dome shaped body having an annular flange for being inserted in a curable material layer, the lateral slopes of the dome shaped body being provided with the reflective surface portions.

10. A surface structure according to claim 8, wherein the protuberance insert is constituted by a substantially circular, solid, substantially dome shaped body having a planar surface for abutting the surface of for instance a kerb stone, the lateral slopes of the dome shaped body being provided with the reflective surface portions.

11. A surface structure according to any of the claims 8-10, wherein the protuberance insert is made of a material such as surgical stainless steel or high density ceramics having a good resistance against surface damage and good light reflection properties.

12. A surface structure according to any of the preceding claims, wherein the height of the protuberances above the surface of the base means and/or the distance between protuberances is chosen such that at least one of the reflective surface portions of a protuberance is not in the shadow of other protuberances for relevant light beams.

13. A surface structure according to any of the preceding claims, wherein the re¬ flective surface portions are distributed such within an array of the protuberances that at least two different visual images are produced by the retro¬ reflection of the light beams for different angles of the light beams relative to the plane of the subsurface and/or relative to a plane perpendicular to said plane.

14. A surface structure according to any of the preceding claims, wherein one or more of the reflective surface portions one or more of the protuberances have a different colour than the rest of said reflective surface portions.

15. A surface structure according to claim 14, wherein and the surface portions having different colours are distributed such within an array of the protuberances that at least two different visual images are produced by the retroreflection of the light beams for different angles of the light beams relative to the plane of the subsurface and/or relative to a plane perpendicular to said plane.

16. A surface structure according to any of the claims 1-4 or any of the claims 8-9 or 11-15 as dependant on any of the claims 1-4, wherein the subsurface is substantially horizontal and the thickness of the layer of curable material decreases towards one or more edges of the area of subsurface covered by said curable material.

17. A surface structure according to claim 6 or any of the claims 8 and 10-16 as dependant on claim 6, wherein at least one protuberance is arranged in a recess in the surface of the kerb stone or paving stone, said recess having a shape allowing light beams emitted by vehicular traffic to be retroreflected.

18. A surface structure according to claim 17, wherein the kerb stone at at least one end thereof is provided with a recess for receiving a pivoting element for allowing two adjacent kerb stones to be mutually joined in a substantially horizontally pivotable manner.

19. A surface structure according to claim 17 or 18, wherein the kerb stone at at least one end thereof is provided with a pivoting element integral therewith.

20. A surface strucmre according to claim 18 or 19, wherein at least one protuberance is arranged on the surface or in a recess in the surface of the pivot- ing element.

21. A surface strucmre according to any of the claims 17-20, wherein the pivot¬ ing element has a substantially circular cylindrical surface.

22. A surface strucmre according to any of the claims 5, 7-15, wherein a sign such as for advertising is arranged pivotable around at least one axis and/or is provided with means for flexing at least a portion of the sign transversly to the plane thereof.

23. A method for producing a surface strucmre according to claim 4, the method comprising the steps of:

- preparing a viscous, curable material having good light reflecting properties in cured condition,

- spreading the material in a substantially even layer on a subsurface,

- curing the layer of curable material.

24. A method according to claim 23, wherein the method comprises moulding the substantially even layer of curable material such that the thickness of the layer of curable material decreases towards one or more edges of the area of subsurface covered by said curable material.

25. A method according to claim 23 or 24, wherein the curable material is prepared in portions with at least two different colours in cured condition, the differently coloured portions being distributed on different areas of the sub¬ surface for achieving the desired distribution of differently coloured reflective surface portions.

26. A kerb stone comprising a light reflecting surface strucmre according to claim 6 or any of the claims 10-15 and 17-21.

27. A pivoting element for cooperation with a kerb stone according to claim 25 and comprising a light reflecting surface strucmre according to any of the claims 6 or 10-15 and 20-21.

28. A paving stone comprising a light reflecting surface strucmre according to claim 6 or any of the claims 10-15 and 17.

29. A road sign comprising a light reflecting surface according to any of the claims 5, 7-8 and 10-15.

30. A road barrier strip comprising a light reflecting surface according to any of the claims 5, 7-8 and 10-15.

31. An advertising billboard for stadiums, roadsides and the like comprising a light reflecting strucmre according to any of the claims 5, 7-8 and 10-15.

32. An advertising billboard according to claim 31 being arranged pivotable around at least one axis.

33. An advertising billboard according to claim 31 or 32, the billboard being arranged for being flexed from a planar configuration to a curved configuration.

34. A kerb stone for sidewalks, highway shoulders or the like, the kerb stone comprising a substantially straight, elongate body provided at at least one end thereof with a pivoting recess for receiving a pivoting element for allowing two adjacent kerb stones to be mutually joined in a substantially horizontally pivot¬ able manner.

35. A kerb stone according to claim 34, wherein the kerb stone at at least one end thereof is provided with a pivoting element integral therewith.

36. A kerb stone according to claim 34 or 35, wherein the pivoting element has a substantially circular cylindrical surface.

37. A pivoting element for being received in a pivoting recess of a kerb stone according to claim 34 or 35.

38. A pivoting element according to claim 37 having a substantially circular cylindrical surface.