Stud for Roads
A road marker 20 comprises a body 22. A photodetector 26 mounted on the body is responsive to illumination by headlights of a first vehicle approaching the body. The photodetector is connected in a circuit 32 on the body also comprising a light emitting device 30. The circuit being configured to energize the light emitting device upon illumination of the photodetector by the head lights of a vehicle approaching the body in a first direction A and the light emitting device is mounted on the body to enhance visibility of the body, particularly for a driver of a second vehicle being driven in a direction B other than the first direction.
This invention relates to road signs such as road markers and more particularly to road studs.
Retro-reflective road studs are well known in the art. These studs are normally mounted in spaced relation relative to one another along a centre and/or side line of a road. Light emitted by the head lights of a first vehicle traveling in a first direction is reflected in an opposite or reverse direction by the stud, to make the stud and hence the line on which it is mounted better visible to a driver of the first vehicle. A problem with this system is that when a second vehicle is approaching the first vehicle from an opposite direction, the head lights of the vehicles ought to be dipped.
The result is that only a few nearby studs reflect light back to the drivers of the vehicles and accordingly the visibility of the line is reduced. Furthermore, the head lights of the approaching vehicle tend to at least partially blind the driver of the other vehicle. Hence, for at least a critical period while these two vehicles are approaching one another from opposite directions, the known road studs and accordingly also the lines on which they are mounted are often not sufficiently visible to either of the drivers.
OBJECT OF THE INVENTIONAccordingly, it is an object of the present invention to provide an alternative road sign, more particularly a road marker and associated method with which the applicant believes the aforementioned disadvantages may at least be alleviated.
SUMMARY OF THE INVENTIONAccording to the invention, there is provided a road sign comprising:
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- a body;
- a photodetector on the body;
- the photodetector being configured on the body to be sensitive to illumination by headlights of a first vehicle approaching the body in a first direction;
- the photodetector being connected in a circuit on the body also comprising a light emitting device;
- the circuit being configured to energize the light emitting device in response to illumination of the photodetector by the head lights of the first vehicle; and
- the light emitting device being mounted on the body to enhance visibility of the body.
The light emitting device preferably emits light in a direction wherein visibility of the body is enhanced for a driver of a second vehicle being driven in a direction other than the first direction.
In one embodiment of the invention the body may be the body of a vehicle carrying the sign.
In another embodiment, the sign may be in the form of a road side marker.
In yet another embodiment, the sign may be in the form of a road surface mountable stud and wherein the body is configured to be mounted on a road surface.
In some embodiments, the photodetector may be a photoswitch connecting the light emitting device to a power supply.
The power supply may be externally of the body and in other embodiments at least part of the power supply may be mounted on the body of the sign.
The power supply may comprise a photosensitive power source and a charge storage device.
In other embodiments, the photodetector is connected to the light emitting device to act as power supply and to power the light emitting device upon illumination of the photodetector. A photoswitch may be connected in the circuit with the photodetector and the light emitting device.
The photodetector may be mounted on one sidewall of the body and the light emitting device may be mounted on another sidewall of the body, such as an opposite sidewall.
A retro-reflector may be mounted on at least one of said one sidewall and said other sidewall of the body.
Also included within the scope of the present invention is a method of signaling to traffic on a road, the method comprising the steps of:
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- providing a road sign comprising a body carrying a photodetector and an electrical circuit connecting the photodetector to a light emitting device on the body;
- utilizing impinging light emitted by headlights of a first vehicle traveling in a first direction to cause the photodetector to cause energization of the light emitting device; and
- causing the light emitting device to emit light to enhance visibility of the body.
The method may comprise the further steps of causing a light reflector on the body to reflect the impinging light in an opposite direction towards the first vehicle and causing the light emitting device to emit light in a direction wherein visibility of the body is enhanced for a driver of another vehicle which is being driven in a direction other then the first direction.
BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMSThe invention will now further be described, by way of example only, with reference to the accompanying diagrams wherein
In
On the line there are mounted in known manner a plurality of road studs 14.1 to 14.n. A first vehicle 16 travels in a first direction A and a second vehicle 18 travels in an opposite direction B.
The known road stud comprises a body mountable on the road surface and carrying a retro-reflector. The reflector in use reflects back in direction B impinging light 17 emitted by the head lights of the vehicle 16. This reflection makes the stud and hence the line more visible to a driver of vehicle 16. However, when a second vehicle 18 approaches the first vehicle, the lights of the vehicles ought to be dipped. This causes the problem referred to in the introduction of this specification in that only one or two nearby studs are illuminated by the head lights of the vehicles to reflect light to the driver of the relevant vehicle, and which problem is aggravated by the temporary blinding effect of the light emitted by the headlights of the other vehicle.
A road sign in the form of a road surface mountable road stud 20 according to the invention is shown in
The photoswitch 26 is electrically connected in a circuit 32 (shown in
Further features of the circuit are shown in
In another form of this embodiment of the stud, a second and similar photoswitch may be provided on sidewall 31 to cause energization of a second LED provided on sidewall 28. In yet another form, a single photoswitch may be provided in a suitable position on the body 22 to cause energization of both the LED's simultaneously. A second retro-reflector may also be provided on sidewall 31.
Another embodiment of the stud is shown at 40 in
In
In
A sign 80 according to the invention may be provided on a carrier vehicle as shown at 80 in
In other applications, a similar arrangement may be used on road side markers or furniture to demarcate a hazardous area or section on a road.
The light emitting devices in all of the aforementioned embodiments may emit light in the red or orange or green parts of the visible spectrum. In other embodiments broad spectrum white light may be emitted.
The aforementioned electrical circuits may comprise means for pulsing energization of the light emitting devices intermittently, including periodically.
Claims
1. A road sign (20, 40, 50, 80) comprising:
- a body (22, 42, 56, 85);
- a photodetector (26, 84) on the body,
- the photodetector being configured on the body to be sensitive to illumination by headlights of a first vehicle (16) approaching the body in a first direction;
- the photodetector being connected in a circuit (32, 68) on the body also comprising a light emitting device (30, 58.1, 86);
- the circuit being configured to energize the light emitting device in response to illumination of the photodetector by the head lights of the first vehicle (16); and
- the light emitting device (30, 58.1, 86) being mounted on the body to enhance visibility of the body (22, 42, 56, 85) for a driver of a second vehicle (18) being driven in a direction (B) other than the first direction (A).
2. A road sign as claimed in claim 1, wherein the body comprises the body of a vehicle carrying the sign.
3. A road sign as claimed in claim 1, wherein the sign is in the form of a road side marker.
4. A road sign as claimed in claim 1, wherein the sign is a road surface mountable stud and wherein the body is configured to be mounted on a road surface.
5. A road sign as claimed in claim 1, wherein the photodetector is a photoswitch connecting the light emitting device to a power supply.
6. A road sign as claimed in claim 5, wherein the power supply is externally of the body.
7. A road sign as claimed in claim 5, wherein at least part of the power supply is mounted on the body of the sign.
8. A road sign as claimed in claim 5, wherein the power supply comprises a photosensitive power source and a charge storage device.
9. A road sign as claimed in claim 1, wherein the photodetector is connected to the light emitting device to act as power supply and to power the light emitting device upon illumination of the photodetector.
10. A road sign as claimed in claim 9, wherein a photoswitch is connected in the circuit with the photodetector and the light emitting device.
11. A road sign as claimed in claim 1, wherein the photodetector is mounted on one sidewall of the body and the light emitting device is mounted on another sidewall of the body.
12. A road sign as claimed in claim 11, wherein a retro-reflector is mounted on at least one of said one sidewall and said other sidewall of the body.
13. A road sign as claimed in claim 1, wherein the light emitting device transmits light in one of the red, orange and green parts of the visible spectrum.
14. A method of signaling to traffic on a road, the method comprising the steps of;
- providing a road sign (20) comprising a body (22) carrying a photodetector (26) and an electrical circuit (32) connecting the photodetector to a light emitting device (30) on the body;
- utilizing impinging light emitted by headlights of a first vehicle (16) traveling in a first direction (A) to cause the photodetector to cause energization of the light emitting device; and
- causing the light emitting device to emit light in a direction wherein visibility of the body (22) is enhanced for a driver of another vehicle (18) which is being driven in a direction (B) other than the first direction (A).
Type: Application
Filed: Jan 21, 2005
Publication Date: Feb 7, 2008
Inventor: Stuart Hume (Knysna)
Application Number: 11/632,606
International Classification: E01F 9/06 (20060101);