TECHNICAL FIELD

This invention relates to rear view mirrors locatable externally of a vehicle

It has long been a problem with external rear view mirrors that rain drops and/or dust collect on the reflective mirror surface thereby limiting the driver's rear view Also, such mirrors encounter a relative airflow on the rear of the mirror due to any forward movement

of the vehicle which increases the drag factor of the vehicle.

BACKGROUND ART

It has been attempted to continually remove raindrops from external rear view mirrors by the use of heaters. This may be acceptable for luxury cars which have electrically operated

adjustable mirrors and therefore already have the required electrical wiring and a power

source. However, such a system is not easily retrofitted and generally does not help the removal of dirt and insects from the reflective mirror surface.

There has also been an attempt to use air that is merely bounced off deflector plates

located near one peripheral side of the mirror. Such attempts are shown in patent documents GB 2153315 and GB 2241211. However, these are inefficient and add significantly to the

aerodynamic drag factor of the vehicle. In particular they deflect air from beyond the extremities of the mirror and do not use the air hitting the rear of the mirror, thereby increasing the drag factor of the vehicle.

It has also been attempted to use funnels or scoops attached to one edge of the mirror to redirect air from an edge of the mirror along a curved scoop exiting across one side of the

front of the mirror surface. Patent document US 4,963,01 1 discloses a flap which extends below the mirror to scoop up the air when required This mirror also does not take any of the air hitting the rear of the mirror which has to be otherwise diverted around the mirror and therefore the drag factor is increased Further a strong hinge and holding means is required

to secure the movable flap in position and so as to be able to withstand the air pressure as the vehicle moves at speed.

Patent documents US 4,898,458, GB 2243586 and GB 2253599 disclose rearview mirrors having a defined channel at the side or rear of the mirror and leading to the front of

the mirror. However, this form of mirror only takes a small portion of the air stream passing

near the edge of the mirror or at the rear of the mirror and allows the majority of the air stream to hit and be diverted around the rear of the mirror which increases the aerodynamic drag of the vehicle.

It has also been attempted, as shown in patent documents US 4,869,581, US 4,979,809 and GB 2175554, to use a curved surface at the rear of mirror and a scoop

attached to one side. Generally the size and angle of the curved surface is ineffective in

redirecting any substantial quantity of air from the rear of the mirror into the scoop. The mirrors of GB 4869581 and GB 2175554 appear to allow at least 50% of the air to deflect around the side opposite the scoop and the aerodynamic surface has about a central third of its size being only slightly curved and more likely to provide a drag factor and torsional forces onto the mirror connection parts by the air flow hitting this region when the vehicle is moving forward than provide an air flow that is directed to the scoop. Although US

4,979,809 has in one embodiment an enclosed curved rear surface to the mirror that is

illustrated to divert the air from across the rear of the mirror to the scoop on only one side, it

would appear that substantial torsional forces would be exerted on the mirror connections and that turbulent flow would occur and probably provide such a back pressure that most of any further air would be directed around the whole of the rear of the mirror.

All of these mirrors also only provide an air stream from one side of the mirror which only cleans the edge of the mirror near the outlet of the scoop or funnel. These mirrors

generally increase the drag factor of the vehicle by using air other than the air that would otherwise hit the rear of the mirror or by not providing an effective aerodynamic structure.

DISCLOSURE OF INVENTION

It is an object of this invention to provide a substantially improved external mirror for a vehicle which can thoroughly clean the mirror surface while not significantly adding to the

aerodynamic drag factor of a vehicle.

In accordance with one embodiment of the invention, there is provided a rear view mirror for external mounting on a vehicle comprising; a mirror body having a front reflective

mirror surface, the mirror body defining a rrtirror air flow volume being the air flow volume that must be redirected around the rear of the mirror body when the vehicle moves forward; a deflector body mounted on the rear of the mirror body to encounter a substantial portion of the mirror air flow volume and outwardly deflect the substantial portion of the air flow volume; and one or more outer walls located outwardly of the deflector body and which with

the deflector body define one or more air flow channels having an opening receiving the

substantial portion of the mirror air flow volume and feeding to air cleaning channels directing air onto the front mirror reflective surface from a plurality of different directions, the air cleaning channels having a smaller flow cross sectional area than the flow cross sectional area of the opening so as to provide a plurality of jetstreams onto the face of the mirror to effect cleaning of the mirror.

In a particular embodiment of the invention, the mirror body comprises: an outer body defining and encircling a central cavity forming an air channel which at one end has a reflective mirror surface, providing a rearward view in use substantially closing the air channel at the one end while leaving a narrow peripheral opening, and at the other end

defines an opening able to receive in use a substantial proportion of the relative airflow

generated by the forward movement of the vehicle and which would hit the mirror body; a deflector body positioned in the air channel with a narrower peak portion of the deflector

body near the opening such that the external sides of the deflector body and the internal walls of the outer body form the air channel, said air channel narrowing as it extends from the opening towards the narrow peripheral openings around the reflective mirror surface and

leading to curved air guides so as to be able to redirect the relative airflow in a substantially laminar flow around the periphery of the reflective mirror surface and onto or substantially

across the reflective mirror surface from a plurality of directions.

The deflector body may be located centrally in the cavity such that the air channel is defined around the periphery of the deflector and provides a uniform and thereby laminar flow. The deflector body may be convex such as a single dome shaped curve which in one

form may be of a circular cross section parallel to the base or may have an oval cross section. Alternatively there may be other shapes of deflector bodies which will provide a laminar deflection of the air entering the opening towards the curved air guides whereby the relative

narrowing of the air channel and the laminar deflection allows for a jet stream exiting the outlets sufficient to clear or clean the front reflector mirror surface. The curved air guides may be integral with the outer body and formed by an extension of the internal walls of the

outer body such that the outer body can be made by moulded plastics However the curved air guides may be flexible such that they are adjustable to direct the air flow in an appropriate direction across the reflective mirror surfc . e with litt significant increase in the aerodynamic

drag factor in the vehicle. Also the curved air guides may be resiliently flexible so that they have an amount of elasticity to cope with partial deformation but return to the original position.

BRIEF DESCRIPTION OF DRAWINGS

In order that the invention is more readily understood, particular embodiments thereof will now be described by way of example only with reference to the accompanying drawings,

wherein:

Fig. 1 is a front perspective view of a mirror in accordance with the first embodiment of the invention.

Fig. 2 is a rear perspective view of the mirror of Fig. 1

Fig. 3 is a front perspective view of an elongated mirror in accordance with a second

embodiment of the invention.

Fig. 4 is a rear perspective view of the mirror of Fig. 3.

Fig. 5 is a diagrammatic view of the mirror of Fig. 3.

Fig. 6 is a sectional view of the mirror of Fig. 5 along the line of VI - VI. MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, there is shown two embodiments of the mirror of the

invention which are similarly constructed but with a different shape and are therefore identified by the same numberings

The mirror 11 of the first embodiment of the invention comprises a mirror body 13 having a front reflective mirror surface 16 allowing for rearward vision when mounted by mount connection 18 to the external surface of a vehicle. The mirror body 11 includes a hollow substantially cylindrical outer body 17 that defines and encircles a cavity 19 with two

opposing openings 22 and 28. One opening 28 of the outer body 17 is substantially closed by the mirror body 13 with its reflective mirror surface 16 facing outwardly through the

opening 28. The other open end of cavity 1 forms a large opening 22. The outer body 17

comprises a cylindrical outer wall 29 with a curved internal wall 30 such that the outer body

17 has a narrower thickness at the end having the opening 22 than the other end which is substantially closed by the reflective mirror surface 16.

The reflective mirror surface 16 is mounted on one side of the mirror body 13 with a convex dome shaped deflector body 31 mounted on the obverse side and extending towards the opening 22 of the cavity 19 and reaching a peak at the opening 22. The dome shape is

substantially symmetrical and parabolic in cross section as shown by Fig. 6. The deflector

body 31 is mounted in the cavity 19 by use of four spaced aerodynamic wings 47 connected between the lower sides of the deflector body 31 and the internal walls 30 of the outer body 17. The wings 47 retain the deflector body 31 in position with its aerodynamic shape

minimising drag on air flow. The curved external sides 32 of the deflector body 31 together with outer walls 30 being the curved internal walls 30 of the outer body 17 form an air flow

channel 21 around the deflector body 31 with the cross sectional area of the air flow channel 21 decreasing from the opening 22 of the cavity 19 and feeding to narrow air cleaning channels 26 formed by narrow peripheral openings 41 around the peripheral edges of the reflective mirror surface 16 and the intemal wall 30 of the outer body 17. The air cleaning channels 21 also include curved air guides 25 extending from the outer walls 30 and redirect

the air flow around the front of and onto the reflective mirror surface 16 by peripheral

overhangs 27 of the outer body 17 partially overhanging the reflective mirror surface 16 and forming the opening 28 of the outer body 17 to allow a substantial portion of reflective mirror surface 16 to be available for use by the driver.

In use the mirror 11 is mounted on the external surface of the vehicle through the

external mount 18 of the outer body 17 such that the reflective mirror surface 16 faces rearwardly relative to the vehicle and the opening 22 faces forwardly and receives air therein

due to the relative air flow caused by the vehicle moving forward. The relative air flow

hitting the mirror body 13 forms a mirror air flow volume that must be deflected around the rear of the mirror body 13. The relative air flow enters the air flow channel 21 and is gently deflected by the convex dome shaped deflector body 31 and the curved outer walls 30. The air flows along the air channel 21 to the air cleaning channels 26 including the peripheral

openings 41 and around the curved air guides 25 and outlets near the entire peripheral edge of the reflective mirror surface 16. The decreasing size of the air flow channel 21, results in a Jetstream of air exiting the outlets 26 and substantially flowing across and onto the reflective

mirror surface 16 from all peripheral edges of the reflective mirror surface 16 to substantially

clean all of the reflective mirror surface 16. The mirror 11 of the second embodiment of the invention is similar to the first embodiment except that the outer body 17 has an outer wall 29 with an oval cross sectional

shape rather than the circular cross sectional shape of the first embodiment. Also, the

deflector body 31 is an elongated convex dome shape which has an oval cross section parallel to its base rather than the substantially circular cross sectional shape of the reflector body 31 of the first embodiment. Extra wings 47 are used to mount the larger deflector body 31 in

the larger cavity 19. The second embodiment is particularly designed for external use on trucks and may be connected thereto by a standard frame 51.

The sizing of the external mirrors is also of importance to ensure there is a laminar flow and to ensure a sufficient effect to provide a jet stream which is substantially laminar and able to clean and keep dry the mirror surface 16.

In the embodiment of the invention shown, the outer wall 29 of the outer body 17 is 190 mm wide with the width of the inner wall 30 near the peripheral openings 41 being 137 mm wide. The base of the dome shaped deflector body 31 is approximately 129 mm wide and thereby provides peripheral openings 41 of a width of about 3 mm. The curved air

guides 25 leading from the peripheral openings 41 have outlets 26 also of a width of about 3 mm. The opening 22 at one end of the outer body 17 has a dimension slightly less than the

190 metres of the cylindrical wall due to the curved inner walls 30 which narrow to the 137 mm width near the base of the dome and the opening 28 has a diameter of about 120 mm. Although the invention is not limited to these particular dimensions or relative dimensions

clearly these dimensions provide a sufficient jet air stream to clear the mirrors very shortly after the vehicle has started moving in the forward direction.

The shape of the mirror can be readily changed as long as the substantial portion of the air is received in the opening 22 and is redirected via air flow channels 21 and air cleaning

channels 26 around at least two peripheral sides of the reflective mirror surface 16. By the use of outlets at opposite peripheral sides of the mirror the air flows can clean the reflective mirror surface by pushing the water droplets or dust to the centre resulting in a larger volume with less surface area contact to the reflective mirror surface. This can assist the water

droplets or dust to be prised off the reflective mirror surface and travel with the air flow exiting through opening 28. Further, since the front reflective surface 16 of the mirror can be located at an angle which is not normal to the direction of the vehicle, then the mirror body can be shaped such that the air is received directly into the opening 22 and the reflector body cculd be shaped to be leading directly into the air flow rather than being at an angle caused by the pivotal rotation of the mirror. Alternatively, the mirror body may be fixed such that it

does not rotate but is always angled such that the opening d the deflector body are facing

directly into the relative air flow and only the rel .ave mirror surface is pivotally mounted on the deflector body.

In a further variation of the rearview mirror shown in Figs. 3, 4 and 5, the elongated

outer body 17 and front reflective surface 16 and deflector body 31 can be constructed in

three parts comprising a central portion, top portion and bottom portion wherein the central portion is substantially rectangular and the top and bottom portions comprise substantially semi-circular top and bottom portions of the mirror. Each portion comprises a part of the

deflector body 31 and outer wall 30. The central portion can be broken to a smaller required size and connected to the top and bottom portions to form a different length of elongated mirror with the top central and bottom portions and their respective part of the deflector body and outer walls combining to function a single unit.