GB2175554A - Cleaning device for vehicle rear-window - Google Patents

Abstract

A rear view mirror assembly 10 comprises a forwardly facing funnel structure 26, 28 serving to funnel air towards a guide surface 30 whereby the air is caused to travel laterally across the surface of the mirror 16, thereby removing and/or maintaining clear of raindrops and the like the mirror surface. <IMAGE>

Description

SPECIFICATION Method and apparatus for optical maintenance This invention relates to a method and a device for maintaining the optical characteristics of an external optical device, such as a rear view mirror, of a vehicle, such as a road vehicle.

In the case of road vehicles such as trucks having laterally positioned external rear view mirrors at opposite sides of the cab of the truck the problem arises that the optical surfaces of the mirrors become optically less effective during use due to the deposition on the optical surface of foreign matter such as dirt and rain and the like. This leads to serious impariment of the optical characteristics of the mirror and this problem is aggravated during the hours of darkness when the lights of vehicles and other sources of illumination cause a mirror which is wet with rain to become virtually useless.

To the best of the Applicant's knowledge there is presently available no effective solution to this problem. Some drivers of trucks occasionally tie a piece of rag to the mirror assembly so that the rag flutters in the wind stream and to some extent wipes over the surface of the mirror. This expedient is found however to be an ineffective solution to the problem.

Of course, it would be possible to fit such a mirror with power driven wiper blades, as indeed is already done in the case of vehicle headlights.

However this is an elaborate and expensive solution to the problem and as such does not really solve it.

Thus, it will be appreciated that there is a considerable need for the provision of a device for maintaining the optical characteristics of an external optical device of a vehicle, such as a rear view mirror, such device offering improvements in relation to one or more of the matters discussed above, or generally.

According to the invention there is provided a device for maintaining the optical characteristics of an external optical device of a vehicle, said device comprising air guide means positioned to guide air across an optical surface of the optical device during travel of the vehicle.

Preferably the air guide means comprises deflector means positioned to direct the air laterally across said optical surface. The air guide means may comprise a curved surface.

The air guide means preferably comprises funnel means. The funnel means is preferably arranged to be forwardly facing with respect to the normal forward direction of motion of the vehicle. The air guide means is preferably positioned at one lateral side edge of the optical device.

The invention also provides a method of maintaining the optical characteristics of an external optical device of a vehicle, the method comprising the step of providing air guide means adjacent the optical device and causing same to produce an air curtain across an optical surface of the device during forward travel of the vehicle.

The invention also provides a method and apparatus for maintaining the optical characteristics of an external optical device of a vehicle comprising any novel feature or novel combination of features disclosed herein.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a front elevation view of a rear view mirror and an associated optical maintenance device; Figure 2 shows an end elevation view in the direction indicated by arrow II in Figure 1; and Figure 3 shows a rear view of the apparatus, the direction of viewing being indicated by arrow Ill in Figure 2.

As shown in the drawings, there is provided a rear view mirror 10 suitable for use on a conventional road vehicle such as a truck. The mirror 10 is mounted outside the cab of the truck at one lateral side thereof and faces rearwardly. The mirror is mounted by means of a mounting 12 to receive the shank of a mounting arm (not shown) connected to the vehicle.

Mounted on mirror 10 at one lateral side thereof is a device 14 for maintaining the optical characteristics of the mirror.

Mirror 10 comprises a silvered reflective surface 16 to provide an image of one side of the vehicle for the driver thereof. The mirror is provided with a convex moulded plastic rear surface 18 carrying a rearwardly projecting support 20 having a cap 22 in which is formed an aperture 24 to receive the mirror mounting spigot (also not shown).

The optical maintenance device 14 comprises surfaces 26, 28 defining a funnel structure extending lengthwise of the mirror and leading to curved guide surface 30. The latter is smoothly curved as shown in Figure 2 to guide air funneled in by surfaces 26 and 28 so that the air is caused to travel laterally of the mirror in the direction indicated by arrow A.

Funnel 26, 28 has an inner edge 32 which slightly overlaps the surface of mirror 16.

Device 14 is in this embodiment fabricated from aluminium. However, it is preferred to construct the optical maintenance device integrally with the mirror from a plastics material.

In use, the mirror assembly 10 moves through the air in the direction indicated by arrow F. The air is funneled inwards by surfaces 26 and 28 into device 14. The air strikes curved surface 30 and is caused to be guided in the direction indicated by arrow A so as to proceed across the surface of mirror 10, laterally thereof. This causes any rain which has settled on the mirror to be displaced laterally thereof. The device also has the effect of reducing the tendency of rain to be deposited on the mirror in the first place. Also, there is the parallel effect of the device that the tendency for dirt and other foreign matter to adhere to the mirror surface is reduced, whereby, all in all, the optical qualities of the mirror are maintained over a longer period of time without mechanical intervention such as wiping the mirror with a clean rag.

Obviously, many modifications could be made in the above-described embodiment while remaining within the scope of the invention. The precise shape and form of the air guide means is suceptible of modification, including the profiles of the air deflecting surfaces, their relative dispositions and their shapes and sizes. Moreover, the air guide means could be provided at any one of the side edges of the mirror. In the above embodiment, as seen in Figure 1 for example, the right hand side of the mirror is the side thereof nearer to the vehicle cab, and thus the device 14 is located at the outer side thereof.

Where the equipment is installed on the mirror during original manufacture, obviously the device 14 can be formed, for example, as an integral moulding with the mirror structure itself and the end support plates 34, 36 will then be formed integrally with the convex rear surface 18 of the mirror structure and likewise the laterally extending support plate 38 will be formed as an integral moulding. However, although this is a matter of manufacturing convenience, it is by no means an essential feature of the invention.

Although in the above embodiment, the invention is described in relation to rear view mirrors, it may well also be applicable to other external optical devices of vehicles, such as lighting units and the like.

In the above embodiment, particular attention is drawn to the features which contribute to the effective passage of air across the mirror surface. It has come to the applicant's attention that previous proposals have been made for devices which seek to reduce the problems caused by raindrops and the like on the mirror surface. Such proposals have included the idea of using a deflector to cause an air current to pass over the mirror surface. To the best of the applicant's knowledge such prior proposals have not proved effective and attention is particularly directed to the features of the above embodiment which contribute to its advance in the art. These features include in particular the funnel structure provided by surfaces 26 and 28 which face forwardly with respect to the direction of forward vehicle travel F.The funnel structure is provided as an assembly which is separate from and in addition to the structure of the mirror itself and its support. The surfaces 26 and 28 diverge in the forward direction and and likewise converge towards the deflector surface 30. It will be noted that the deflector surfaces are located entirely forwardly of the mirror surface 16. Moreover, in addition, the mirror surface is seen to be flat, with no peripheral beading or lip to interfere with the smooth flow of air over it. In one preferred version of the invention, the mirror surface is slightly convex, as seen by the user. Some adaptation of the relationship of the air guide surface 30 to the mirror surface may be needed in this latter case.

A further feature of the embodiment of Figures 1 and 2 lies in the relationship of the edge 32 of the deflector surface 30 in relation to the mirror surface 16. As can be seen in Figure 1, the edge 32 slightly overlies the mirror surface. Moreover, the disposition of the curved air guide surface 30 in relation to the mirror is preferably such that the direction of discharge of air is not only laterally across the mirror surface but slightly forwards with respect to direction F so as to positively impinge on the mirror surface. In addition, the assembly is preferably provided with structure 40 closing in the assembly 10 whereby the only air which is permitted to enter the assembly and be deflected across the mirror surface is that which enters the wide, open mouth of the funnel assembly.

It will be appreciated that the provision of the funnel assembly greatly increases the efficiency of the apparatus by amplifying the volume of air passing across the mirror surface, whereby the required velocity of vehicle travel for effective operation of the device is reduced.

Accordingly, important sub-features of the invention disclosed and claimed herein include the provision of funnel means facing forwardly with respect to direction F. The funnel means comprises two forwardly diverging funnel members. The funnel members are located forwardly of the air guide means, and forwardly also of the mirror itself.

Claims (7)

1. A rear view mirror assembly for a vehicle, the mirror assembly comprising air guide means positioned guide air across an optical surface of the mirror during travel of the vehicle, wherein forwardly facing funnel means is provided to collect air and funnel it to the air guide means.

2. Apparatus according to claim 1 wherein said funnel means is located on the outboard side of the mirror, with respect to the body of a vehicle on which it is to be mounted.

3. Apparatus according to claim 1 or claim 2 wherein the air guide means is disposed to cause air to travel laterally and slightly forwardly with respect to the direction of vehicle travel, as the air leaves the air guide means.

4. Apparatus according to any one of the preceding claims wherein the mirror surface is substantially flat.

5. Apparatus according to any one of claims 1 to 3 wherein the mirror surface is convex.

6. Apparatus according to any one of the preceding claims wherein the mirror is mounted without any lip or peripheral rib or raised portion to interfere with the smooth airflow over the mirror.

7. A rear view mirror assembly substantially as described herein with reference to the accompanying drawings.