GB2210917A - Reflective road marker - Google Patents

Abstract

A road marker comprising a body (10) having an upper surface (15) to be mounted in the plane of a road surface, wherein the body has a circularly cylindrical outer configuration (11) and has a through going opening transverse to the plane of said upper surface with a reflector (13) arranged along the entire circumference of the opening, said reflector having a reflection surface corresponding to the inner surface of a truncated, inverted cone or truncated, inverted pyramid having retro-reflection characteristics independent of the angle of incidence of light from a vehicle headlamp. <IMAGE>

Description

A REFLECTIVE MARKER The present invention relates to reflective markers, for example highway markers to be placed in road surfaces such that incident light from vehicle headlights is reflected by the marker, giving vehicle drivers an indication of the position of their vehicle relative to the marker.

Various forms of highway markers are known.

In US Patent No. 4136990 there is described a marker having a body which is recessed in the road surface for laying in the same plane. However, the prior art marker is not easy to mount, partly because of the outer configuration thereof and the existence ot a closed bottom, but also because of difficulties of orientation originating from the fact that the reflection surface of the marker merely is capable of providing retro reflection of light having angles of incidence perpendicular to the four planar reflection surfaces. In practice this means that the marker is useful only at four-road junctions.

On the other hand, U.S. Patent No. 4155666 describes a road surface marker having a circular outer configuration. However, the possibility of mounting it in a road surface is heavily restricted tor several reasons; firstly, a ramp extends above the plane of the road surface, which has to be oriented such that, for instance, a snow-plough blade is guided along the ramp. Additionally, there is only one pair of planar reflection surfaces along a very limited portion of the circumference meaning that the ability of the reflector surfaces to retro reflect light is strictly dependent on the direction of the incident light from a vehicle head lamp.

In order to eliminate the drawbacks within the present field, the present invention provides a highway marker comprising a body, which is to be recessed in the road surface and which is provided with means for reflection of incident light.

The marker is distinguished by a body having a through going downwardly tapering hole transver to its top plane, and in that the means for reflection comprise a reflector having a reflection surface arranged around the circumference of the opening, preferably round the entire circumference and having retro reflection characteristics independent of the angle of incidence or light from a vehicle head lamp.

In the preferred embodiment the dimensions of the through-going hole are such that the reflector is cleaned by passing vehicle wheels.

Preferably, the outer configuration of said body is that of a circular cylinder.

In order to increase the useful lifetime of the highway marker of the present type, each reflector preferably comprises reflector sections which are operatively independent of each other.

Two embodiments ot highway markers according to the present invention are shown in the accompanying drawings, where: Figure 1 shows a marker having a reflection surface corresponding to the inner surface of a truncated, inverted conical body, Figure 2 shows a marker having a reflection surface corresponding to the inner surface of a truncated, inverted, polygonal pyramidal body, Figure 3 is a section showing either of the highway markers in Figure 1 and 2 recessed in a road surface, and Figure 4 is an enlarged partial section of Figure 2 showing the facet structure of the surface 13a.

The highway marker 10 in Figure 1 comprises a body 10, for instance of plastics or suitable material from a traffic safety point of view, having a circularly cylindrical outer surface 11. A through going, downwardly tapering hole having an upper edge 12 and a lower edge 14 is provided in the top surface of the body. The edge 12 defines the lower end edge of a circumferential wall 13 facing the interior region of the body. At the top thereof, the wall 13 is defined by the upper top edge 14 defining the dimension of the opening at the planar upper side 15 ot the body 10. As appears from Figure 3, the dimension of the opening is such that it is larger at the top than at the bottom meaning that the wall 13 defines a surface, which corresponds to the inner surface ot a truncated, inverted cone.

In Figure 2 the edges 12a and 14a represent regular polygons meaning that the surface 13a may be described as the inner surface of a truncated, inverted, polygonal pyramid.

The diameter ot the opening in the bodies 10, 10a is approximately 10 cm and the height of the circularly cylindric surface is approximately 1-3 cm.

In practice such dimensions have proved to make the highway marker self-cleaning.

As appears from Figure 3, the highway marker is intended to be mounted in the plane 16 of the road surface with the planar upper edge 15 falling in such a plane, meaning that a planar transition region is formed that does not hinder maintenance vehicles.

Preferably, the surface 13 has an inclination of trom 30 to 609 relative to a central vertical axis.

The surface 13 is provided with reflecting material along the entire extension thereof. Such reflecting material is of a type known per se, for obtaining a retro reflection, for instance of the type comprising a planar outside and "internal pearls", or prisms, i.e. material of the type generally used for reflection plates or reflectors on vehicles. Other types of reflecting material or coating are of course possible. The surfaces 13, 13a and the reflection material thereof provide a retro reflection practically independent of the angle of incidence of light from a vehicle headlamp. This also means that the marker 10, as far as retro reflection is concerned, is insensitive to the orientation thereof in the road surface around a vertical centre axis.

As the retlector body has a circularly cylindrical outer configuration 11, there are no difficulties whatsoever in mounting the markers in standard size holes in a road surface, regardless ot whether the road is straight or curved.

As appears trom Figure 3, the opening in the body 10 also allows minor irregularities 17 to protude from the plane of the lower surface 18. This facilitates the mounting by simply drilling a hole having a well defined circular groove of a width corresponding to the width of the lower side 18, which in practice is a very simple operation.

The limited height of the highway marker 10 means that when repairing the road surface coating, the old marker simply may be covered by a new coating whereatter a new opening or hole for a new marker is formed.

The reflecting coating on the surface 13 preferably is arranged as several reflector segments operatively independent of each other, which allows an acceptable operation even after destruction of some segments.

At least in its preferred embodiments, the invention provides a marker meeting the following characteristics: The marker should be easy to mount in the road surface. The marker should give an acceptable so-called retro-reflection under all weather conditions and said retro-reflection should be substantially independent of the angle of incidence of iigflt trom a vehicle headlamp.

The marker should be self-cleaning.

The marker should be safe in use.

The marker should be strong enough to resist damage by maintenance vehicles.

The marker should not pose a risk to maintenance vehicles.

The marker should have a reflector which is simple to replace.

The marker's height should be easy to adjust when laying out a new road surface.

Claims (8)

1. A reflective marker, comprising a body (10) adapted to recessed in the plane of a surface (160 and comprising means (13) for reflection of incident light, characterised in that the body has a through going downwardly tapering hole transversally to its top plane and that said means for reflection comprise a reflector (13) arranged around the circumference of said opening and having retro-reflection characteristics independent of the angle of incidence for light from a vehicle headlamp.

2. A reflective marker as in Claim 1, characterised in that the dimensions of the through going hole are such that the reflector is cleaned by passing vehicle wheels.

3. A reflective marker as in Claim 2, characterised in that the outer shape (11) of the body is that of a circular cylinder.

4. A relfective marker as in Claim 2, charactersied in that the marker comprises several reflector sections operatively independent of each other.

5. A reflective marker, substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

6. A highway marker, comprising a body (10) adapted to be recessed in the plane of a surface (16) and comprising means (13) for reflection of incident light, characterised in that the body has a circular outer configuration, that the body has a through going hole transverse to the plane of said outer configuration, and that said means for reflection comprise a reflector (13) arranged around the entire circumference of said opening and having a reflection surface corresponding to the envelope surface of a mould for a truncated, inverted cone or truncated, inverted pyramid having corresponding retro reflection characteristics independent of the angle of incidence for light from a vehicle headlamp.

7. A method of marking a surface for the passage of vehicular traffic which will comprises providing a marker as claimed in any one of Claims 1 to 6 in the road surface.

8. A method as claimed in Claim 7, wherein the top surface of the marker is flush with the said traffic surface.