GB2160004A

GB2160004A - Improvements relating to audible warning devices

Info

Publication number: GB2160004A
Application number: GB08506451A
Authority: GB
Inventors: Patrick Joseph Lally; George Albert Willi Sturtivant
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-03-15
Filing date: 1985-03-13
Publication date: 1985-12-11
Also published as: GB2160004B; GB8506451D0

Abstract

A method of improving the safety of road-works 21 comprises placing an audible warning device 20 at the road-works to alert blind or visually impaired pedestrians 23 to the road-works. The audible warning device includes a sound generator emitting a pulsed warning signal which may be automatically adjusted, to compensate for ambient noise levels, by means of an ambient sound control unit. Alternatively a generating unit emitting an electronic signal may be placed at the road-works, the electronic signal activating a receiver/sonic transmitter carried by the pedestrian. Or the generating unit may be carried by the pedestrian and the receiver/sonic transmitter may be placed at the road-works. The audible warning device may be disguised as a brick or a piece of timber, or may be incorporated in a hazard warning light. In a further form, the audible warning device is included in a vehicle door and is activated upon opening the door. <IMAGE>

Description

SPECIFICATION Improvements relating to audible warning devices This invention relates to an audible warning device and particularly to such a device when used to alert blind pedestrians of hazards in their path.

Hithertofore, in full daylight road cones have been used to alert pedestrians to any obstacles in their path. At night, or in poor light, flashing road warning lights are used. Although such devices have served to reduce accidental collision by sighted pedestrians they are obviously useless with regard to the safety of blind pedestrians.

The present invention overcomes this problem and also reduces the chances of collision by partially sighted pedestrians, or fully sighted pedestrians who are not wholly attentive.

The present invention is a method of improving the safety of an excavation or the like by siting at least on audible warning device at the excavation to alert blind or visually impaired pedestrians of the existence of the excavation.

Preferably the audible warning device can form part of a flashing road light.

Advantageously the audible warning device may comprise a sound generating unit for emitting an audible warning signal, the sound generating unit being coupled to a sound control unit which automatically adjusts the volume of the warning signal such that the warning signal may be heard above ambient sound. According to a feature of the invention the audible warning device may generate an intermittent signal for enhanced discernment.

The frequency of such a signal may be variable.

Alternatively the audible warning device may be contructed to generate a series of allophonic sounds for voice synthesis so that the blind pedestrian has a worded indication of the type of a hazard he is about to encounter and what action he must take.

In a further form the audible warning device may include a magnetised clamp for fixing the device to ferrous objects. Alternatively the warning device may include a suction cup for such similar purpose. The warning device may be designed in the form of a piece of rock or a piece of timber for the prevention of theft, or it may be lockable to other objects which are not easily misappropriated.

Prior to the invention audible warning devices have been used in conjuction with road crossing systems to gain the attention of both sighted and unsighted pedestrians. However, no such devices have been applied to excavation and the like despite a requirement in Chapter 8 of the Traffic Safety Measures for Road Works (of the Traffic Sign Manual), which states that the law requires protection to be provided for all road users including blind persons. In fact obstacles and excavations have been enclosed by barriers which in themselves have represented a hazard to blind persons. In crowded areas, or on crowded pavements, such barriers are often a hazard to sighted pedestrians whose line of sight is blocked by those in front. An audible warning device used in conjuction with such barriers would increase their safety.

In accordance with the present invention a method of using an audible warning device at an excavation or the like will now be described by way of example only with reference to: Figure 1 which illustrates the construction of the audible warning device; and Figure 2 which illustrates the operation of the audible warning device at an excavation.

Referring to Figure 1, a warning device includes a sound generating unit comprising a tone generator 1 which produces an electrical wave form of set frequency. This wave form is switched through a tone gate 2 to a tone amplifier 3 and an output transducer 4. The tone gate 2 is controlled by a silent period timer 5 and a period timer 6. These timers which may be variable, activate the tone for a short period and repeat the tone at regular intervals.

An ambient level sensor 7 is used to detect the ambient noise level and produce a related signal.

This signal is amplified by an ambient level amplifier 8 which is connected thereto.

The ambient level sensing circuit is rendered inoperative when the tone is sounded thereby preventing the tone being added to the ambient noise level. This is achieved by disabling an ambient level gate 9 with the signal from the tone gate 2.

The uncorrupted ambient noise level signal from the ambient level gate 9 is then processed by an ambient level averaging and hold unit 10. The hold unit 10 produces a voltage which is proportional to the average ambient sound level over a short period of time, whilst the ambient level gate 9 is disabled. The resulting signal is then amplified by an output level controller 11 and used to control the gain of the tone amplifier 3 and hence the level of sound emitted by the output transducer 4 which operates a speaker 12.

In effect the warning device will emit a low level pulsed signal in an area of low ambient noise and will automatically adjust to a louder signal in response to passing traffic of general noise. The device may include a volume control and may be powered by battery.

With reference to Figure 2 an audible warning device 20 is shown in situation at an excavation 21 protected by a barrier 22. The warning device 20 is placed forward of the excavation and the barrier such that it may attract the attention of an oncoming blind person 23 in sufficient time for that blind person to react.

In an alternative form the warning device may be incorporated within a flashing road light and operated from a common battery. In such a form the speaker 12 would be mounted within the road light casing suitably vented for to permit the transmission of sound.

In a further form and as an aid to blind or visually impaired pedestrians the device may be a transmitter of electronic signals, rather than sonic signals, which activates a receiver/sonic transmitter carried by such pedestrians. Alternatively, the blind person could carry the transmitter with the device as the receiver/sonic transmitter.

In a varied form, for fully sighted persons, the warning device may include a photo-electric cell to activate the device when ambient light falls below a certain level.

As well as excavations, the device may be used on vehicle doors, which often extend across pavements, the device may be activated on the opening of the door. The device may also be designed to emit a directional signal.

Although an audible warning device has been described in the form of an electrical construction it is anticipated that such a device could be constructed from mechanical components, using for example a wind-up spring as an energy source.

In an advanced form the warning device might be fitted with an infra-red detector such that it may be activated on the approach of a pedestrian.

Claims

1. A method of improving the safety of an excavation or the like by siting at least one audible warning device at the excavation to alert blind or visually impaired pedestrians of the existence to the excavation.

2. An audible warning device for use in a method according to Claim 1 comprising a sound generating unit for emitting an audible warning signal, the sound generating unit coupled to an ambient sound control unit which automatically adjusts the warning signal so that it may be heard above the ambient sound.

3. An audible warning device as claimed in Claim 2 wherein the sound generating unit emits an intermittent signal.

4. An audible warning device as claimed in Claim 3 wherein the frequency of the intermittent signal is variable.

5. An audible warning device as claimed in Claim 2 which generates allophonic sounds for voice synthesis so that a blind person may have a worded indication of the hazard he is approaching.

6. An audible warning device as claimed in any one of the Claims 2 to 5 including a fixing means secured to other objects or surfaces.

7. An audible warning device as claimed in Claim 6 wherein the fixing means is a magnet such that the warning device may be attached to ferrous objects.

8. An audible warning device as claimed in any one of the claims 2 to 7 which is disguised as a brick or a piece of timber or the like to reduce the likelihood of misappropriation.

9. An audible warning device as claimed in Claims 2 to 9 in which the sound generating unit emits a directional signal.

10. An audible warning device for use in a method according to Claim 1 comprising a generating unit which emits an electronic signal to activate a receiver/sonic transmitter carried by a blind or visually impaired pedestrian.

11. An audible warning device for use in a method according to Claim 1 comprising a receiver/sonic transmitter activated by a generating unit which emits an electronic signal and which is carried by an approaching blind or visually impaired pedestrian.

12. An audible warning device as claimed in any one of Claims 2 to 9 which includes an infrared detector such that it may be activated on the approach of a pedestrian.

13. A hazard warning light including an audible warning device as claimed in any one of Claims 2 to 12.

14. A vehicle door including an audible warning device as claimed in any one of Claims 2 to 12 which, upon opening, activates the warning device.