GB2244362A - Low bridge warning - Google Patents

Abstract

Apparatus, intended to warn the driver of a road-going vehicle that the bridge he is heading towards is too low for his vehicle to pass under, comprises: a length of wire, cable, or other appropriately elongate line; means attaching the opposite end regions of the line, in use, to stanchions spaced some way along the road from the bridge, so that the line spans the road just below - or at - the underbridge height; means tensioning the line between its opposite end regions; means allowing the line to give, temporarily overcoming the tension, when the line is struck by the vehicle; and means then activating a signal, warning and/or obliging the driver to stop before he reaches the bridge. <IMAGE>

Description

LOW BRIDGE WARNING Background to the Invention The invention relates to apparatus intended to warn the driver of a road-going vehicle that the bridge he is heading towards is too low for his vehicle to pass under.

There are many such bridges throughout the United Kingdom.

They present a real problem to road travel in these days of ever-larger freight-transporting lorries. The same problem does not arise with rail bridges because they are from the outset constructed to accommodate the trains that pass under them. Or alternatively, given an "inherited" bridge, the trains - which are all administered by one principal authority are constructed to pass under the bridges.

With road-going transport, by contrast, there is no single authority to dictate the design of vehicles which pass under bridges. Many of the bridges in this country are very old indeed and could not easily be replaced, or raised in underbridge height. And even something as apparently simple as resurfacing the road that passes under the bridge can cause sufficient restriction in new under-bridge height to make the bridge a hazard to vehicles that would previously with luck have got underneath it.

Accidents when vehicles hit the underside of a too-low bridge can be quite devastating. Double-decker buses are a frequent victim and to see the top region of the top deck effectively shawn off in such circumstances is disconcerting to any onlooker.

The risk of injury to the passengers on the top deck hardly needs emphasising.

Freight-carrying lorries in the form of high-sided vans and trucks are equally at risk. And there is the increased risk that comes with the increasing numbers of European ex-UKoriginating vehicles on British roads, as these vehicles tend if anything to be even larger than their UK counterparts.

Summary of the Invention Apparatus intended to warn the driver of a road-going vehicle that the bridge he is heading towards is too low for his vehicle to pass under; the apparatus comprising a length of wire, cable, or other appropriately elongate line; means attaching the opposite end regions of the line, in use, to stanchions spaced some way along the road from the bridge, so that the line spans the road just below - or at - the under-bridge height; means tensioning the line between its opposite end regions; means allowing the line to give, temporarily overcoming the tension, when the line is struck by the vehicle; and means then activating a signal, warning and/or obliging the driver to stop before he reaches the bridge.

Preferably the signal activating means is adapted to be mounted on the vehicle and, when so mounted, activates a signal generator which is also mounted on the vehicle.

Preferably, in the case just outlined, the signal generator, when activated, triggers a visual, audible and/or vehicle brake applying, signal.

Embodiments of the invention will now be described with reference to the accompanying drawings.

Brief Description of the Drawing The single Figure of the accompanying drawings shows diagrammatically one way in which the invention might be put into practice.

Description of the Preferred Embodiments In the drawing, a road 11 passes over a relatively low bridge 12 which carries another road 13 over the first road 11 at the usual approximately right-angled intersection.

The under-bridge height H of the bridge is restricted, and certain vehicles (high-sided freight carriers, for example) will find it difficult, if not impossible, to manoeuvre underneath the bridge if they are heading towards it on road 11.

A warning system is installed on each opposite side of the bridge to cater for this risk. The system comprises stanchions 14 which are spaced some way along the road from the bridge 12 in respective pairs and which support, between them, a line 15 in such a way that the line 15 spans the road 11 just below - or at - the under-bridge height.

The line 15 is tensioned between its opposite end regions so as to stay substantially straight, and taut, at a constant height above the surface of the road 11. There are a number of ways in which this tensioning can be achieved and they can be used either alone or in combination.

For example, the line 15 might extend over pulleys carried on the respective tops of the stanchions 14, to end in weights which hang down to keep the line under tension normally.

Alternatively the line may itself be made of an inherently tensioned construction exemplified by a coiled tension spring.

Again, the stanchions 14 themselves may be sufficiently inherently flexible to be held by the line 15 against their resilience.

Yet again, the stanchions 14 might be hinged part-way along their length, with the hinge incorporating a torsion spring which normally holds the stanchions substantially upright along their entire lengths and hence holds the line 15 taut.

Whatever method is used, the line can give, temporarily, when (as is the intention) it is struck by a too-high vehicle passing under it before the vehicle reaches the bridge 12.

The inherent resilience of the line 15 may provide the necessary give, or the ability of the stanchions 14 to deflect, or both these in combination.

This striking of the line 15 by the vehicle then activates a warning signal with the intention that the driver will stop before he reaches the bridge. The warning signal can take several forms, singly or in combination with one another.

In broad terms it can be a signal which warns and/or obliges the driver to stop when the line has been hit.

The distance D by which the stanchions 14 are spaced along the road from the bridge 12 will be dictated by the expected reaction time of the driver and the impact that the signal makes on his senses and/or his vehicle once it has been activated.

The signal could comprise STOP lights - for example flashing red lights - mounted on the bridge and readily visible as the vehicle approaches. Such lights could alternatively or additionally be mounted on the roadside between the stanchions 14 and the bridge 12 to give even more warning of the danger that the driver faces if he carries on under the bridge.

They could be combined with, or replaced by, readily audible sirens and again these would most probably be of the intermittent-sounding kind for maximum impact on the driver' s senses.

Means activating this signal, in themselves, can readily be supplied by the intended skilled addressee of this specification. The signal may, for example, be generated in response to electronically-observed movement of the line 15 and/or of the stanchions 14. It could alternatively be generated by electronic circuitry linking one or both these items to the signal generator at or near the bridge. No specific means are illustrated in the drawing because of the variety of means that could be employed and because it is not necessary to try to pre-empt that choice once the need for such means has been stated.

In another embodiment of the invention, the signal-activating means takes the form of a trigger which is adapted to be mounted on the vehicle roof. The way in which the trigger is constructed and mounted on the vehicle can, again, be determined by the skilled reader without further unnecessary instruction. The intention in this embodiment is that the trigger hits the line 15 and then activates a signal inside the vehicle or outside it but, in either event, with the signal generating means mounted on or travelling with the vehicle.

For example, a warning light on the vehicle's dashboard could immediately start to flash. A warning siren, preferably intermittent-sounding, could start and in this instance the siren might well deliberately be mounted outside the vehicle so that the driver, whilst warned, is not unduly startled with possibly dangerous results. The warning might be routed through the vehicle's horn-sounding circuit.

Alternatively, or additionally, in certain circumstances, the signal generator might trigger a mechanism which applies the vehicle's brakes. This would have to be done carefully and at the design stage it would need a number of investigations.

But it is a possibility and is within the scope of the invention.

The modern vehicle's air-actuated brakes lend themselves to this sort of adaptation and such brakes are now overwhelmingly common on large freight-carrying vehicles.

Once again, means whereby the trigger generates such a signal and as a consequence the brakes are applied, are within the scope of the skilled reader in this field. But in a case such as this, where the vehicle is safely brought to rest, such means may additionally apply the hazard warning lights of the vehicle so that subsequent traffic is not caught unawares by the presence of a stationary vehicle in the middle of the road.

In practical embodiments, the line 15 will almost certainly be plastics-covered to guard against the effects of weather - and to minimise any damage caused by the vehicle having to hit it in order to trigger the warning. The stanchions could be constituted by the sides of high-sided buildings adjacent the bridge. Means to cancel the warning signals could be provided on or adjacent the bridge so that, when the driver has got out of his vehicle, he can effectively reset the system. The roof-mounted trigger (or simply linehitting projection not necessarily functioning as a signal-activating trigger) could have a smooth and rounded leading edge so curved as to deflect the line 15 rather than to drag it along once the vehicle has hit it.

Where the signal-generating unit is on or adjacent the bridge, rather than the vehicle, it may be governed by a time switch.

When actuated, in such instances, it will stop and reset itself automatically after the preset time has elapsed. It needs no intervention from the vehicle driver.

Signals on or adjacent the bridge may be activated as well as, not just as alternatives to, signals activated on the vehicle itself. This maximises the chance of the driver doing something before it is too late.

Other modifications will become apparent to those skilled in the field to which the invention relates.

Claims (4)

CLAIMS:

1. Apparatus intended to warn the driver of a road-going vehicle that the bridge he is heading towards is too low for his vehicle to pass under; the apparatus comprising a length of wire, cable, or other appropriately elongate line; means attaching the opposite end regions of the line, in use, to stanchions spaced some way along the road from the bridge, so that the line spans the road just below - or at - the underbridge height; means tensioning the line between its opposite end regions; means allowing the line to give, temporarily overcoming the tension, when the line is struck by the vehicle; and means then activating a signal, warning and/or obliging the driver to stop before he reaches the bridge.

2. Apparatus according to Claim 1 and in which the signalactivating means is adapted to be mounted on the vehicle and, when so mounted, activates a signal generator which is also mounted on the vehicle.

3. Apparatus according to Claim 2 and in which the signal generator, when activated, triggers a visual; audible; and/or vehicle brake applying, signal.

4. Apparatus substantially as described herein with reference to and as illustrated in any appropriate combination of the accompanying drawings.