GB2113280A - Improvements in reflector systems - Google Patents

Abstract

There is described a reflective system for delineating roadways and road-side works. The system comprises a cord adapted to be supported along the road to be delineated and carrying a plurality of reflectors. In the preferred embodiment the reflectors are rotated by wind and are thus self-cleaning. <IMAGE>

Description

SPECIFICATION Improvements in reflector systems Background of the Invention This invention relates to a reflector system for returning light towards its source, particularly to reflector systems used to delineate roads and to a novel reflector for use in such systems.

The risk of a road accident more than doubles at night. Roadworks are particularly hazardous, because of the confusing variety of signs and barriers which are used to delineate the road.

A further problem exists in that the reflectivity of previous reflectors could be nullified by mud or other opaque material adhering to them. As a result they could not be relied upon to delineate a road effectively. While reflectors of the 'cats-eye' type are self cleaning this action depends on overrunning by traffic. Thus, they are particularly prone to damage, and are expensive to install and replace. Also, they are not suitable for temporary use.

Summary of the Invention In is an object of the present invention to provide an improved reflector system for delineating roads which is inexpensive to manufacture and easy to install.

It is a further of the present invention to provide a reflector system to delineate a road which has self cleaning properties.

According to the present invention there is provided a reflector system comprising a cord adapted to be tensioned between two fixed supports, the cord being provided with a plurality of reflectors mounted on the cord at spaced locations along the length of the cord.

Preferably, the reflectors are rotatably mounted at each location.

Further according to the present invention there is provided a reflector comprising a boss adapted to be rotatably mounted on a support and at least one reflective blade mounted on said boss.

Description of the Drawings Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of one embodiment of a reflector system made in accordance with the present invention; Fig. 2 is a perspective view, to a larger scale, of part of the system of Fig. 1 showing a reflective disc; Fig. 3 is an elevational view illustrating a reflector system made in accordance with the present invention and utilising a preferred embodiment of reflector; Fig. 4 is a perspective view illustrating a preferred embodiment of reflector of the system of Fig. 3; Fig. 5 is a front elevational view of the reflector of Fig. 4:: Fig. 6 is sectional view, to a larger scale, of part of the reflector of Fig. 4 taken along the line A-A; Fig. 7 is a part-sectional view, to a larger scale, of part of the reflector of Fig. 4 taken along the line BB of Fig. 6; Fig. 8 is a side elevational view of the reflector of Fig. 4; Fig. 9 is a side elevational view of the reflector of Fig. 1 deformed by centrifugal forces; Fig. 10 is a perspective view of a modified reflector having eight blades; Figs. 11, 1 2 and 1 3 illustrate the reflector of the present invention mounted, respectively, on a crash barrier, a rigid marker or hazard post and a pliant post;; Fig. 14 iilustrates, in perspective, the reflective discs of the system of Fig. 1 provided with rotating blades for self cleaning; Fig. 1 5 illustrates an alternative form of reflective disc for use with the system of Fig. 1 and provided with a cooperating rotating blade for self cleaning.

Referring to the drawings, and in particular to Figs. 1 and 2, there is illustrated a basic reflective system made in accordance with the present invention. The reflective system comprises a cord 1 2 adapted to be tensioned between support posts 10. The support posts 10 may be wooden stakes, traffic cones or alternatively may be other supports, such as hooks fixed in a wall. The supports delineate road-side works which are to be cordoned off or otherwise highlighted by the reflective system.

Fixed to the cord 1 2 at spaced locations are a plurality of reflective discs 1 3 mounted on the cord 1 2 by means of locating collars 14 which may be crimped to the cord or otherwise adhered thereto. Alternatively, the collars 14 may be replaced by knots on either side of the reflective disc 1 3. The reflective disc 1 3 is formed of plastics or suitable planar material and is provided with retro-reflective material on its flat surfaces. To comply with conventional practice one side of the disc may be provided with a white retro-reflective surface whereas the other side is provided with a red retro-reflective surface.Clearly, if desired, both sides of the disc may have reflective surfaces of the same colour or even each side of the disc may be provided with contrasting coloured retroreflective surfaces.

By way of explanation, retro-reflective surfaces are surfaces which reflect light directly back to its source irrespective of the angle of incidence of the light beam to the surface.

Thus, when tensioned between posts along the verge or central reservation of a road, the reflective discs 13 are automatically orientated to face the headlights of vehicles to give maximum reflectivity. If spaced closely along the cord 1 2 the reflective discs 1 3 will appear to coalesce into a glowing line, so providing excellent delineation.

Figs. 3 to 9 show a preferred embodiment of a reflector system made in accordance with the present invention. In this embodiment, the reflective discs 1 3 are replaced by rotating reflectors 23 mounted on a cord 22 fixed to support posts 20. The reflectors 23 each comprise a central spherical boss 24 adapted to be rotatably mounted on spindles 25 fixed at spaced locations on the cord 22. Each reflector 23 has a pair of substantially semi-circular blades 30 and 31. The blades 30 and 31 are fixed to the boss 24 at an angle to the axis of rotation and in the embodiment illustrated the angle is shown to be 65 degrees. This angle gives an optimum combination of rotational speed and reflective effectiveness.

By virtue of the fact that the reflectors 23 are free to rotate on the cord 22 the wind forces tending to move the reflectors axially along the cord are reduced, these forces effecting rotation of the reflectors.

The boss 24 and blades 30, 31 are preferably formed by a two part moulding which allows the reflector to be snap fitted over the spindles 25. To this end, the boss has two cooperating halves 24A, 248 having a snap joint 32 as illustrated in Fig. 7. The spindles 11 which are fitted at spaced distances on a supporting cord 22 may be replaced by knots or other suitable plastics fasteners which clip over the cord 22.

The reflectors 23 are preferably moulded from polypropylene which includes an ultra-violet stabiliser and fluorescent red pigment. Each blade 30,31 is provided with white self-adhesive retroreflective material on one of its sides. The side of the blade 30 having reflective material being opposite the side of the blade 31 having reflective material.

The preferred surfaces for the reflector material are fluorescent red, for daytime, and retroreflective white, for headlights at night, a combination which is common on other road safety equipment. Each side of a reflector has a red and a white blade. When rotating at night this tends to appear as a circular white reflector with a flickering or shimmering effect.

The central boss 24 is preferably hollow, to minimise cost, to allow the respective locating spindle 25, knot or fastener to be enclosed, and to reduce the moment of inertia, so increasing the rate of rotational acceleration in variable winds.

Rotation of the blades reduces the accretion of any impinging material, both by inducing centrifugal forces and by increasing the scouring action of rain. The impact speed of raindrops is increased by the movement of the rotating blades towards them, and their cleaning action is also improved by the centrifugal and Coriolis forces which accelerate them across the reflective surface. The reflective performance of the blades is also improved by their angle to the plane of rotation, which increases the range of angles through which incident light can be retroreflected. Low inertia is particularly useful to benefit from vehicle slipstreams, especially in calm conditions. The amount of dirt thrown by wheels on to a reflector will tend to increase with the number, speed and size of vehicles and with their proximity to the reflector.Similarly, increase in these factors increases the speed of the slipstream. Thus, the self cleaning effect due to rotation will tend to be self-regulating.

Moment of inertia and cost are also reduced by making the blades 30, 31 as thin as practicable. A thin blade is more resistant to fracture due to impact or crushing, and the flexibility of a thin blade also produces a 'feathering' action which retards rotation in high winds.

A blade which does not flex appreciably can rotate so fast that the adhering reflective material could be dislodged by shear forces due to centrifugal force. But a more flexible blade is deformed by centrifugal force so that its flat surface becomes an S curve as seen in Fig. 9. The gap between a pair of blades thus decreases and the Venturi effect of airflow passing through the gap will increase, so sucking the blades still further together. As deformation from a plane surface increases, so also does co-efficient of wind drag. Thus, rotation is increasingly retarded as wind speed rises.

Damage at high speeds would be aggravated if the reflector was out of balance. This could occur if water collecting in the lower half of the hollow boss were to freeze. Thus, the boss can have two or more drainholes 35.

In the embodiment of Fig. 10, a reflector 43 has a larger number of blades 50, in the case illustrated, eight. The blades 50 are radially fixed to a boss 44 mounted for rotation on cord 42 and are flat to facilitate the application of retroreflective material or fabrication of integral corner cube reflectors. The flat blades 50 also make aerodynamic efficiency independent of the axial direction of the wind. Each blade is a segment of a circle so that the reflector 43 appears circular when viewed in an axial direction.

In Fig. 11, rotating reflectors 63 as shown in Fig. 4 are fixed by brackets 64 to a typical Wsection crash barrier 66 and in Fig. 12 reflectors 73 are shown attached to a rigid verge marker or hazard post 75.

Also, a reflector 83 may be rotatably attached to a pliant post 85 as illustrated in Fig. 13. The post 125, made of plastics material such as polypropylene, can deflect under vehicle impact and then return to its original position. The footing 87 comprises triangular, vertically mounted plates in metal or plastics material. This shape facilitates installation by vertical driving, and gives a disposition of plate material which efficiently utilises the resistance of the ground to overturning pressures. The post may be integral with the footing, or fixed in a socket 89.

In the alternative embodiment of Fig. 14 a stationary, reflective disc 93 is mounted on a cord 92 co-axial with and close to a pair of wind-actuated, rotating cleaning blades 97 of thin, transparent, pliant, plastics material. The pressure of the wind on the blades 97 forces their trailing edges 98 against the disc 93 as the blades rotate, so tending to wipe off any material adhering to the disc. The stiffness of the blades 97 is selected to maximise rotational speed thus giving the required cleaning action.

In Fig. 15, a conical stationary reflective disc 103 is used to increase the range of angles of incidence at which light can be reflected. A pair of cooperating rotating cleaning blades 107 having angled trailing edges 108 are used to wipe the reflective conical surface of the disc 103.

Claims (16)

1. A reflective system comprising a cord adapted to be tensioned between two fixed supports, the cord being provided with a plurality of reflectors mounted on the cord at spaced locations along the length of the cord.

2. A reflective system as claimed in claim 1, wherein the reflectors are in the form of plastics discs provided with retro-reflective material on at least one face thereof.

3. A reflective system as claimed in claim 2, wherein the discs are located by means of collars fixed to the cord.

4. A reflective system as claimed in claim 2, wherein the discs are held by knots in the cord.

5. A reflective system as claimed in any preceding claim, wherein the discs are held at an angle to the axis of the cord.

6. A reflective system as claimed in any preceding claim, wherein the reflectors are rotatably mounted on the cord.

7. A reflective system as claimed in any preceding claim, wherein the reflectors include a spherical boss rotatably mounted at a fixed position on the cord, the boss carrying at least one reflective blade extending radially thereof.

8. A reflective system as claimed in claim 7, wherein two substantially semi-circular blades are provided.

9. A reflective system as claimed in either claim 7 or claim 8, wherein the boss is formed of two hemi-spherical parts adapted to be snap-fitted together over a bearing spindle fixed to said support.

10. A reflector comprising a boss adapted to be rotatably mounted in a support and at least one reflective blade fixed on said boss.

11. A reflector as claimed in claim 10 wherein the boss is spherical and the blade extends radially thereof.

12. A reflector as claimed in either claim 10 or claim 11, wherein two substantially semi-circular blades are provided.

13. A reflector as claimed in claim 12, wherein the blades are angled with respect to each other and to the axis of rotation of the support.

14. A reflector as claimed in any one of claims 10 to 13, wherein the boss is formed of two hemispherical parts adapted to be snap-fitted together over a bearing spindle fixed to said support.

1 5. A reflective system substantially as hereinbefore described with reference to the accompanying drawings.

16. A reflector substantially as hereinbefore described with reference to the accompanying drawings.