GB2339947A

GB2339947A - Warning that a vehicle is too high

Info

Publication number: GB2339947A
Application number: GB9814053A
Authority: GB
Inventors: Walter Johnston Halkerston
Original assignee: HALKERSTON JEAN
Current assignee: HALKERSTON JEAN
Priority date: 1998-06-29
Filing date: 1998-06-29
Publication date: 2000-02-09
Anticipated expiration: 2018-06-29
Also published as: GB2339947B; GB9814053D0

Description

2339947 BREDGE PROTECTION SYSTEM This invention relates to a system for

the protection of bridges and other similar structures. In particular it relates to a system for alerting drivers of high-sided vehicles to a risk of damage to a structure through which the vehicle must pass, and to monitoring this structure for damage caused by collision with such a vehicle.

Where a road passes under a low bridge structure there is a risk that a high vehicle will collide with the bridge, potentially causing it damage. In the case of a bridge carrying railway track over a road, for safety reasons, if such a collision occurs, however minor it may seem, all traffic on the railway line must be suspended until the track has been checked for potential damage. Even a small track misalignment may be sufficient to cause an unacceptable increase in the risk of derailment of a train. Collisions happen with a sufficient frequency to make them a significant and expensive cause of disruption to a train service.

At present lorry drivers rely on fixed signs warning of a low bridge ahead and a knowledge of their vehicle's height. However, the height of some vehicles, for example those transporting containers, can change from day to day and written information in the cab, to alert the driver to the height of the vehicle, is not always up to date. A known height monitor comprises a fight source and light detector mounted on poles and arranged to ride a beam traversing the road at 900 at the height to be monitored. The height detector activates a warning sign briefly, whilst the beam is broken. Since the light source and detector are typically mounted relatively close to the bridge and since the warning is only briefly illuminated, lorry drivers frequently do not see the warning sign.

As existing warnings are frequently unseen or ignored by drivers of highsided vehicles, there is a need for a system to detect the approach of high- sided vehicles, preferably at a significant range, and to activate a warning sign that is clearly visible to the vehicle's driver.

According to one aspect of the invention there is provided apparatus to provide an indication to a driver of a conveyance that the conveyance exceeds a predetermined height, the apparatus comprising a sensor configured to mount on an architectural structure and to detect a conveyance exceeding the predetermined height; and a warning device coupled to the sensor and configured to mount on the architectural structure, to provide a warning to the driver that the conveyance exceeds the predetermined height; wherein the sensor detects reflection of electromagnetic radiation from the conveyance and has a laminate conveyance-detecting region extending and diverging from the sensor.

Preferably, the electromagnetic radiation is infrared laser radiation and wherein the conveyance-detecting region is substantially fan-shaped.

Preferably, the sensor en-its a pulse of radiation and detects a reflection within a predetermined time window, whereby the conveyance-detecting region extends to a is predetermined range.

Preferably, the warning is provided for a predetermined interval.

Preferably, the warning is provided at least whilst the conveyance is in the conveyance-detecting region.

Preferably, the apparatus further comprises means to record an image of the conveyance. Typically the image recording means comprises a video camera and video recording means, wherein the video recording means is coupled to the sensor and controlled to record an image of a conveyance exceeding the predetermined height.

The apparatus may further comprise track alignment monitoring (TAM) means.

Typically, the TAM means is coupled to the sensor to monitor track alignment in response to detection of a conveyance exceeding the predetermined height. Preferably, the apparatus is configured to monitor track alignment for a predetermined interval after detection of a conveyance exceeding the predetermined height and to store corresponding track alignment information.

In a second aspect, the present invention provides a railway bridge fitted with the apparatus described above.

In a further aspect, the present invention provides a method of providing an indication to a driver of a conveyance that the conveyance exceeds a predetermined height, the method comprising: providing a sensor to detect reflection of electromagnetic radiation fi7orn the conveyance, the sensor having a laminate conveyance- detecting region extending and diverging from the sensor, mounting the sensor on a bridge at substantially the predetermined height; and coupling the sensor to a driver warning device to warn the driver that the conveyance exceeds the predetermined height.

Preferably the apparatus further comprises means to record an image of the conveyance and, optionally, track alignment monitoring means.

In order to promote a fuller understanding of the above and other aspects of the present invention, some embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure I shows a side elevation of a conveyance approaching a railway bridge upon which is mounted an embodiment of the apparatus in accordance with the first aspect of the present invention-, Figure 2 shows a plan elevation of the arrangement of Figure I Figure 3 shows a driver's view of the bridge of Figure I - and Figure 4 shows a block diagram of an embodiment of a bridge-strike prevention system in accordance with the present invention.

Referring to Figures I and 2, a conveyance 14, typically a high-sided lorry, is shown approaching, an architectural structure 12, typically a railway bridge, in the direction shown by arrow 16. A sensor 18 is mounted on bridge 12, the sensor emitting electromagnetic radiation shown illustratively by dotted fine 20. The sensor 18 is mounted at a height above road surface 13 corresponding to a predetermined height of conveyance for which it is desired to provide a warning. The sensor operates by detecting a reflected electromagnetic radiation from the high vehicle and the radiation is preferably infrared light from a laser. Infrared light is used for safety reasons; the coherence of the laser allows the sensor to be designed so that a beam of a well defined shape and boundary is emitted. From Figure 2 it can be seen that the beam 20 diverges from the sensor in a fan shape. In one embodiment, the beam has a 3m width 300m from the sensor and a vertical spread at that distance of approximately I cm. The sensor is arranged so that the beam is directed along the road towards the approaching traffic at a substantially constant height (the predetermined height of interest) above the road surface. Typically, the beam height will be set a little way below the actual maximum safe height for vehicles to pass through the bridge, to allow margin of error. In many cases the permitted height of vehicle win depend upon the vehicles width and the shape of the bridge.

The laser is preferably range gated, to provide an adjustable window of detection range. The laser is arranged to emit a pulse of light and the time of the return of the pulse will depend upon the distance of the vehicle 14 from the sensor 18 (it will be approximately twice the distance between the vehicle and the bridge divided by the speed of light). If the sensor is gated so that only reflections within a given time window are detected, this will effectively constrain detection of vehicles to a given distance window.

Advantageously, this allows the range of sensor 18 to be reduced to match a particular installation of the apparatus.

A significant feature of the apparatus is that a vehicle-sensitive detecting region is provided which extends over a substantial length and width ofthe road, by contrast with prior systems. Once a vehicle is at or exceeds the predetermined height is detected, warning device 22 can signal a clear warning to the driver of the vehicle. As illustrated in Figure 3), this may include an illuminated sign reading "TOO 1UGFr' and flashing lights 23. Since sensor 18 is directed along the road rather than across the road as in prior systems, an approaching vehicle can be detected much earlier and the warning displayed in good time. In prior arrangements physical and environmental constraints would invariably mean that a sensor could be positioned at most 50m away from the bridge leaving little time for a warning. Furthermore, in its simplest configuration the warning device can be coupled directly to the sensor to show a warning for the whole time vehicle 14 is in the conveyance detecting region. Prior arrangements, which use just such an approach, only provide a brief warning because the vehicle detecting region is merely a line rather than a plan. Preferably, however, the warning is displayed for a predetermined interval sufficient to cause the vehicle to stop or at least slow down. In other embodiments the display is capable of providing a variety of different warning messages.

Preferably the display is fully weatherproof and highly visible in all conditions including bright sunlight.

In the preferred embodiment shown in Figure 3, the system may also include means to record an image of the potentially offending conveyance. This facilitates a claim on the vehicle's insurance should the driver ignore the warning and the vehicle strikes a bridge. An image capture device may be triggered by the sensor to provide a still or moving picture of the vehicle; a conventional "wet film" camera, or a video camera or other means may be used. Preferably, as illustrated, a video camera 32 is mounted on the bridge. This can be coupled to an analogue or digital video recorder controlled by the sensor so that the image of the approaching vehicle is obtained. Most simply, an image of every vehicle which exceeds the predetermined height can be captured. If it is desired to conserve video storage, only recordings of those events which disturb the track (see below) need be retained. In a conventional manner, the video recording preferably includes other relevant data such as time, date, location etc. The stored images may be downloaded electronically by attaching a transmitter and control receiver 36 to the video recorder (see Figure 4). The camera 32 may be configured in a conventional manner so that it is not blinded by headlights of oncoming vehicles at night.

For safety reasons, if a bridge carrying railway line is struck by a conveyance travelling under it, as a matter of course the line is closed until after any possible disturbance or damage has been inspected and assessed. For this reason, the system can be advantageously provided with track alignment monitoring means 26. In one embodiment such a monitoring means comprises a laser (typically infrared) transmitter 28 and reflector 29, both of which are attached to the track 24. Figure 2 shows such an arrangement attached to one rail but advantageously both rails are monitored. Laser beam is used to very accurately measure the distance between transmitter 28 and reflector 29, on the underlying, and verified, assumption that disturbance to the track will always change this distance albeit only by a little. In one embodiment, the transmitter and receiver are spaced approximately 30m apart and the monitoring device is arranged to measure distance changes of Imm. The sensitivity of the system may be increased by increasing the transmitter-receiver separation and by increasing the distance measurement accuracy. In a preferred embodiment the track monitoring means is activated when the sensor detects that a vehicle which exceeds the predetermined height is approaching.

Preferably data from the track alignment monitoring means is stored together with a high vehicle's image, either in a bespoke digital video recorder or in separate storage means.

Figure 4 shows a block diagram of one embodiment of the system. Sensor 18 is coupled to display unit 22 and to track alignment monitoring means 26. The sensor is also coupled to the trigger input 35 of video recorder 34, which receives video information from video camera 32. Video recorder 34 may be coupled to a transmitter and control receiver 36 and antenna(s) 37 to permit remote downloading of stored video information, Preferably the sensor is also attached to a counter 3 8 which advances each time the system is triggered by an approaching high-sided vehicle.

Although the system has been described with reference to its use to detect high lorries approaching a railway bridge, it also finds other applications. For example it may I I I be used to detect the collision of barges with bridges or collisions of vehicles in general with car park or building entrances.

Claims

I. Apparatus to provide an indication to a driver of a conveyance that the conveyance exceeds a predetermined height, the apparatus comprising:

a sensor configured to mount on an architectural structure and to detect a conveyance exceeding the predetermined height-, and a warning device coupled to the sensor and configured to mount on the architectural structure, to provide a warning to the driver that the conveyance exceeds the predetermined height; wherein the sensor detects reflection of electromagnetic radiation from the conveyance and has a laminate conveyance-detecting region extending and diverging from the sensor.
2. Apparatus as claimed in claim I wherein the electromagnetic radiation is infrared laser radiation and wherein the conveyance-detecting region is substantially fan-shaped.
3. Apparatus as claimed in claim I or 2 wherein the sensor emits a pulse of radiation and detects a reflection within a predetermined time window, whereby the conveyance-detecting region extends to a predetermined range.
4. Apparatus as claimed in any one of claims I to 3 wherein the warning is provided for a predetermined interval.
5. Apparatus as claim in any one of claims I to 4 wherein the warning is provided at least whilst the conveyance is in.the conveyance-detecting region.
6. Apparatus as claimed in any preceding claim further comprising means to record an image of the conveyance.
7. Apparatus as claimed in claim 6 wherein the means to record an image comprises a video camera and video recording means, wherein the video recording means is coupled to the sensor and controlled to record an image of a conveyance exceeding the predetermined height.
8. Apparatus as claimed in any preceding claim further comprising track alignment monitoring (TAM) means.
9. Apparatus as claimed in claim 8 wherein the TAM means is coupled to the sensor to monitor track alignment in response to detection of a conveyance exceeding the predetermined height.
10. Apparatus as claimed in claim 9 configured to monitor track alignment for a predetermined interval after detection of a conveyance exceeding the predetermined height and to store corresponding track alignment information.
11. A railway bridge fitted with the apparatus of any preceding claim.
12. A method of providing an indication to a driver of a conveyance that the conveyance exceeds a predetermined height, the method comprising:

providing a sensor to detect reflection of electromagnetic radiation from the conveyance, the sensor having a laminate conveyance-detecting region extending and diverging from the sensor; mounting the sensor on a bridge at substantially the predetermined height; and coupling the sensor to a driver warning device to warn the driver that the conveyance exceeds the predetermined height.
13. Apparatus substantially as described with reference to Figures I to 4.