FIELD OF THE INVENTION

This invention relates to optical elements and, in particular, to warning devices comprising optical elements. The invention extends to a visual warning device that can be mounted on a vehicle or to a road side barrier, or used as road signage.

BACKGROUND OF THE INVENTION Fundamental considerations of road safety require that areas deemed to be dangerous or hazardous be demarcated by means of visual warning devices so as to be visible to, for example, road users and pedestrians not only in good weather, but also in bad weather conditions where poor visibility is a common problem.

Similarly, large vehicles, such as trucks, are usually required by law to have passive visual warning devices or reflectors arranged on rear and lateral sides thereof to lighten up, by way of light reflection, said vehicles and emphasize their presence and, in particular, their position, lengths and widths. Thus, the passive visual warning devices or reflector attracts the attention of other road users as same approaches the large vehicle, or provides a warning to motorists approaching said large vehicle when same is stopped in a dangerous position on a road.

Reflective strips of material are often used as passive visual warning devices or reflectors and mounted onto rear, front, and/or sides of large vehicles. Although these strips do reflect incident light, projected onto them by oncoming traffic, they often lack effectiveness in unfavourable weather conditions such as fog and rain. The applicant, therefore, believes that a need exists for more effective visual warning devices that can be mounted on vehicles or road side barriers, or even used as road signage to improve the visibility of vehicles, barriers and signage in poor visibility conditions. SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention there is provided a visual warning device comprising:

a reflector arrangement having at least one reflective face operable to reflect and send light projected thereon away from each of a rear, side and front of the reflector arrangement; and

illumination means having at least one element which is a source of light arranged to illuminate the at least one reflective face so as to enhance in use the reflective properties of the visual warning device.

In accordance with a second aspect of the invention there is provided a visual warning device that can be fitted to a vehicle to reflect and send light projected thereon towards each of the rear, side and front of the vehicle, said device comprising: a reflector arrangement having at least one reflective face operable to in use reflect and send light projected thereon towards each of the rear, side and front of the vehicle; and

illumination means having at least one element which is a source of light arranged to illuminate the at least one reflective face so as to enhance in use the reflective properties of the visual warning device.

There is also provided for the at least one reflective face to be a single arcuate face, which is arranged, in use, to reflect both incident light and light originating from the illumination means. Alternatively, and more preferably, there is provided for the reflector arrangement to include a set of substantially planar reflectors, each reflector having a separate reflective face, which is arranged, in use, to reflect both incident light and light originating from the illumination means.

Moreover, the visual warning device includes a housing having at least one side wall that defines an enclosed space, said side wall having at least one recess in which the at least one reflective face is operatively secured so that said face forms a window for the housing. The housing is typically, but not necessarily, a substantially square or rectangular container comprising front, rear, and side walls between a base and a top, at least three of the walls, each defining a centrally located recess for receiving a reflective face. According to a preferred embodiment of the invention, each reflective face comprises a different colour.

There is further provided for the at least one element of the illumination means to be operatively positioned within the enclosed space and behind the reflective face so as to project light onto a rear surface of said face. Alternatively, the at least one element of the illumination means is operatively positioned external to the housing so as to project light onto a front surface of said at least one reflective face. In the latter case, the at least one element of the illumination means is immovably-mounted to said at least one side wall or reflective face.

In addition there is provided for the housing to operatively house wiring that carries circuitry for powering the illumination means and to include mounting means for mounting the device to a substrate. The at least one element of the illumination means is either an incandescent or non-incandescent light source such as, for example, a light emitting diode (LED). Typically, the at least one reflective face is formed from light reflective tape, reflective plastics, phosphorous or light emitting substances, or reflective glass lenses.

There is also provided for the device to include a power source in the form of a coin cell, solar cell, wind generator, or a mechanically powered capacitor or flywheel. Particularly, the wind generator includes a fan arrangement mounted to the device so as to be exposed to, and rotatable by, wind flow, which rotation produces AC current for powering the illumination device. More particularly, in respect of the mechanically powered capacitor, mechanical power is produced when a magnet is slid back and forth through a spool of copper wire, such sliding movement being the result of, for example, vehicle on-road vibration which, in turn, induces AC current in loops of wire to charge the capacitor that powers the illumination means. The invention also extends to a method of enhancing the visibility of a vehicle and for providing an indication of the relative dimensions of said vehicle, the method comprising the steps of:

attaching at least three visual warning devices as described hereinabove, along at least one side of the vehicle or along the underside of the vehicle adjacent at least one side thereof; spacing said devices along said at least one side at a predetermined constant distance from one another, thereby providing a series of equally- spaced devices along said side of the vehicle and thus providing said indication of the length of said vehicle; and

orienting said devices in use, to not only reflect incident light towards the rear, side and front of the vehicle, but also light originating from the illumination means.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are now described, by way of example, with reference to the accompanying non-limiting diagrammatic drawings. In the drawings: Figure 1 shows a side view of visual warning devices according to a first embodiment of the invention mounted to and used on a flat-bed truck;

Figure 2 shows a front perspective view of one of the visual warning devices of Figure 1 ;

Figure 3 shows an enlarged side view of the visual warning devices of

Figure 1 ; Figure 4 shows a front perspective view of a visual warning device in accordance with a second embodiment of the invention;

Figure 5 shows a partially cut-away front view of the visual warn device of Figure 4; Figure 6 shows a partially cut-away front view of a visual warning device in accordance with a third embodiment of the invention;

Fv igure 7 shows a partially cut-away front view of a visual warning device in accordance with a fourth embodiment of the invention;

Figure 8 shows a partially cut-away front view of a visual warning device in accordance with a fifth embodiment of the invention; and Figure 9 shows a circuit diagramme depicting power supply and illumination means of a visual warning device in accordance with a further embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENT

In the drawings, like numerals generally indicate like components, unless otherwise indicated.

Referring to the drawings, reference numerals (10), (100), (200), (300) and (400) generally depict a visual warning device in accordance with different embodiments of the invention. It should be understood that the exemplary devices (10), (100), (200), (300) and (400) described below are not intended to limit the invention in any way and are provided only to describe specific ways in which the invention could work.

In Figures 1 and 3, the visual warning device (10) is shown in a mounted position on a flat-bed truck (1 1 ) in accordance with a first embodiment of the invention. Although not shown in the drawings, it is envisaged that, in other embodiments of the invention, the visual warning device (10), (100), (200(300) and (400) may also be mounted on road side barriers, or even used as road signage to facilitate safe road use in conditions of poor visibility. As shown in the drawings, the device (10) includes a reflector unit having a box-like housing (12) and a mounting means (14) (better shown in Figure 2) for mounting the housing (12) to a fixed point (16) on an exterior part of the truck (1 1 ). Each fixed point (16) is a predetermined point on a side of the truck (1 1 ) or along the underside of the truck (1 1 ) adjacent a side thereof. It will be appreciated that depending on the shape and configuration of the side of the truck, a suitable bracket (not shown) such as, for example, a U-shaped bracket may have to be used to mount device (10) to the truck's side.

Although, the mounting means (14) may include other arrangements such as, for example, adhesive strips for attaching the housing (12) to the truck (1 1 ), it is shown here to be securable by a bolt (18) and nut (20). The bolt (18) extends approximately normally from a roof (22) of the housing (12) and which, in use, is locatable through a hole (24) in the roof (22) and an aperture (not shown) in the side, or underside, of the truck (1 1 ) whereupon it is secured by the nut (20).

The housing (12) of the reflector unit is fabricated from a plastics material, but it is anticipated that other materials such as, for example, metal alloys and the like may also be used. The housing (12) has a substantially planar square base (26) with four substantially planar square vertical side walls (28) extending from the sides of the base (26). The vertical side walls (28) are slightly slanted outwards and arranged so that they form the roof (22) which has an approximately planar square face parallel to the base (26), but with a somewhat larger surface area than that of the base (26).

Each side wall (28) further includes a recess (30) in which a generally flat disklike reflector (32) is received so that its reflective surface forms a window for the housing (12). The reflector (32) is not only able to reflect and send light projected thereon by, for example, oncoming traffic, towards each of the rear, side and front of the truck (1 1 ), but is equipped with features, which to the surprise of the inventors, enhance in use the reflective properties of the device (10). The enhancing features referred to are illumination means (34) (not shown in Figures 1 to 3 as same are hidden within an enclosed internal spaced defined between the base (26), roof (22), and side walls (28)). Illumination means (34) are arranged to illuminate each reflector (32) either from behind or from the front.

On the other hand, the reflectors (32) are formed by light reflective tape, alternatively by reflective plastics material or glass lenses. Light emitting substances such as phosphorous material may also be used. Shapes and configurations other than the substantially planar surface shape of the reflectors (32) are also envisaged and are believed to also fall within the spirit and scope of the invention. For example, the reflector may include a single arcuate face as reflective surface, which face is arranged in use to not only reflect incident light towards the rear, side and front of a vehicle, but also light originating from the illumination means operatively positioned behind or in front of said reflector. Referring to Figures 4 and 5, the illumination means (34) of the visual warning- signal device (100) is located external to the housing (12) as opposed to the internal housing thereof in Figures 1 to 3. Each illumination means (34) is arranged to project light, preferably at an angle of 45 ^° , onto a corresponding reflector (32). The illumination means (34) is typically, but not necessarily, a light emitting diode (LED). Other light sources, whether non-incandescent or incandescent bulbs, may also be used. The LED (34) is immovably-mounted relative to the reflector (32). Moreover, there is provided for the housing (12) to operatively house wiring that carries circuitry for powering the illumination means (34). The power source typically comprises AAA illumination means (34) or AA rechargeable batteries (36) which is electrically coupled via wiring (38) to the LED (34). Alternatively, and as depicted in Figure 6, a solar cell (40), suitably positioned on the device (200), provides electrical current to operate the LED (34).

In an even further embodiment of the invention, a mechanically powered capacitor (50) (or even flywheel) provides the operating current for the LED (34) of the device (300) shown in Figure 7. The mechanical power is typically produced by the sliding of a magnet (52) back and forth through a spool of copper wire (54). Such movement may be caused by the truck (1 1 ) as it vibrates when driving on a road so that current is produced in the loops of wire which, in turn charges the capacitor (50) so that it can provide a current to the LED (34).

In a yet further embodiment of the invention as shown in Figure 8, a wind powered visual warning device (400) can be used according to a method of the invention. Device (400) includes a wind-driven fan (56) which is secured to base (26) and has a shaft (58) rotatably coupled to an alternator armature for producing electricity from mechanical rotation. The fan (56) may be any fan which is converted to produce AC current such as, for example, a 12V DC brushless computer processing unit case fan or ice box fan. As shown in the circuit diagramme of Figure 9, a combined wind and solar powered module may also be used to provide lighting for a lighting circuit of the illumination means.

In this case, a first charging circuit consists of above wind generator, a bridge rectifier to convert alternating current to direct current, a current limiter for ensuring that current produced does not exceed a specified limit, as well as a photo transistor for, voltage is produced in light, therefore the transistor will be used to determine when the lighting circuit will be activated.

Charging circuit 2 comprises a 4V-6V solar cell and a diode to ensure low leakage current. The cell has a height of between 40-60mm and a length of between 20-30mm, which cell is also capable of being used to determine when the lighting circuit should be activated.

The lighting circuit is typically provided with a switch or decision circuit for choosing between wind or solar power. The lighting circuit further includes three AAA batteries or two AA rechargeable batteries to ordinarily power the circuit, a PIC microcontroller to drive the LEDs to ensure minimal power usage and to determine when to drive the LEDs, a programming interface to program the microcontroller with suitable software for the two charging circuits, and 3mm or surface mount LEDs to illuminate device.

In an embodiment of the invention, each reflector (32) includes a different colour and, the LED's colour conforms to that of the reflector (32) which it illuminates. For example, an operatively front facing reflector and LED provide white light, while the operatively rear facing reflector and LED provide red light, whereas the operatively side facing reflector and LED provide amber light.

When a truck (1 1 ), for example, is equipped with the devices (10), (100), (200), (300), or (400) and it is on a road or alongside a road in bad weather conditions, the devices will be perceived by the driver of a vehicle approaching from the side as a series of "lights" (e.g., amber) and as a series of "lights" (e.g., white) to the driver of a vehicle approaching from the front and as a series of "lights" (e.g., red) to the driver of a vehicle approaching from behind. In each case the number of "lights" will provide information on the dimensions of the vehicle and enable, or warn, the driver of an approaching vehicle to act in accordance with this information. While specific embodiments of the present invention have been described above, one skilled in the art will recognize that numerous variations or changes may be made to the visual warning devices described above without departing from the ambit of the invention.

Thus, it will be understood that the description and drawings is not intended to limit the extent of the invention, but rather it is intended to cover all modifications and methods, including: methods, for manufacturing components of the visual warning devices (10), (100), (200), (300), and (400) falling within the spirit and the scope of the invention.