GB2106845A

GB2106845A - Vehicle reversing aid

Info

Publication number: GB2106845A
Application number: GB8214013A
Authority: GB
Inventors: Reeve Philip Harrison
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-07-28
Filing date: 1982-05-13
Publication date: 1983-04-20
Also published as: GB2106845B

Abstract

A generally convex mirror (16) in is supported on stays (15) above a base (18). A smaller planar auxiliary mirror (23') is fixed to another set of stays (24). The stays (15) can pivot about the base (18), and the stays (24) can pivot about the back of the convex mirror housing (17), enabling the auxiliary mirror (23') to be brought above and in line with a vehicle towing hook (27) and the convex mirror (16) to be brought above and in line with the auxiliary mirror (23') when the base (18) is attached magnetically to the vehicle bodywork above the towing hook (27). The implement is used in combination with an approach-guiding wand (13) supported on a horse shoe (14) carrying balancing weights (14a, 14b) and projecting from a trailer hitch. A vehicle driver can first "sight" the towing hook (27) in his vehicle interior rear view mirror, and then reverse towards the trailer hitch using the convex mirror (16) and the wand (13) to position the hook accurately beneath the hitch. <IMAGE>

Description

SPECIFICATION Vehicle reversing aid The invention relates to vehicle reversing aids.

The invention particularly concerns an assembly to aid the driver of a towing vehicle in positioning his towing hook under the hitch of a waiting trailer (as interpreted herein). The towing vehicle must usually be reversed towards the trailer. Very often the driver cannot judge his final line of approach accurately.

Almost always, he has to twist round in his driving seat in order to obtain any kind of view of the trailer, and this can affect dangerously his control of his vehicle.

If the driver is elderly, or not especially agile, he may find it very difficult to twist round in his seat. Even if he is young and relatively fit, he will find that many modern saloon cars (especially those big enough to tow a sizable trailer such as a caravan) have high-backed seats which make it difficult for him to twist round. Very often these seats have headrests which makes life even more difficult in this context. Worst of all, the back end of the car will inevitably cut off the driver's view of the trailer hitch as he draws close to it, at the very moment when he needs to be able to see it in order to position his hook accurately beneath it.

According to the invention, an implement to aid the driver of a towing vehicle in positioning his towing hook under the hitch of a waiting trailer comprises a generally convex mirror (as interpreted herein) with a line-ofapproach end-point marked on its reflecting surface; an auxiliary mirror; means for mounting the mirrors in use, firmly but detachably on the vehicle above the towing hook and in a position in which an image of the convex mirror can be seen in the vehicle's normal interior rear view mirror; means of adjustment allowing the auxiliary mirror to be brought above and in line with the towing hook, and allowing the convex mirror to be brought above and in line with the auxiliary mirror, so that the auxiliary mirror reflects an image of the marked line-of-approach end-point, and of the normal rear view mirror, into the eye of a person looking down into the auxiliary mirror; and means holding the convex mirror in that position whilst allowing the auxiliary mirror then to be moved away into a position in which it is no longer interposed between the convex mirror and the towing hook.

A driver standing at the back of his vehicle can use the two mirrors to "sight" the line-ofapproach end-point in his rear view mirror and to superimpose its image on the image of the hook which he will see when he looks into his interior mirror from his driving seat. If he reverses slowly towards the waiting trailer, and approaches the trailer accurately, the trailer hitch will eventually be reflected in the convex mirror of the implement and an image of the hitch will appear in the driver's interior rear view mirror. If he continues to reverse slowly, so steering his vehicle as to make the image of the hitch eventually superimpose on that of the hook, he will then have positioned his towing hook directly beneath the hitch of the waiting trailer.

Thus the driver can "set up" the vehicle mounted implement unaided, sighting the line-of-approach end-point in the interior mirror without having to be able to look into the interior rear view mirror itself. If he judges his initial reversing approach towards the trailer correctly he can complete the final stages looking forward into his rear view mirror without having to twist round in his seat, and hence with his vehicle under maximum control.

The line-of-approach end-point may be marked directly on the reflecting surface of the convex mirror. Alternatively or additionally it may comprise a hole in the mirror. This would enable an observer to look directly down through the hole when sighting the endpoint in the auxiliary mirror.

The so-called generally convex mirror need not necessarily have a constant-radius or a constantly-curving reflecting surface. For example, the surface region containing the lineof-approach end-point marking should be planar, with the rest of the surface curving along a constant radius or along a progressively sharper radius. Or said rest of the surface may comprise one or more further planar mirrors angled with respect to said planar surface or, as the case may be, to one another to form a succession of tangents to a curve not necessarily of constant radius.

The implement is preferably used in conjunction with an approach-guiding wand which, in use, is mounted on the trailer on or adjacent the hitch in such a manner that when the wand is viewed in the vehicle's interior rear view mirror, a line appears to project vertically from the hook-receiving portion of the hitch.

That image of the line will be reflected directly into the driver's rear view mirror and will appear above, or appear to extend both above and below, the image of the convex mirror containing the line-of-approach endpoint marking superimposed on the towing hook.

If the driver, looking forward into his rear view mirror, so steers his vehicle as to keep the directly-reflected approach-guiding-line image vertically in line with the indirectlyreflected hook image, he need not turn round in his seat at all, not even during the early stages of approach towards the trailer. He will be able to see the approach-guiding-line (and the rest of the trailer intially) directly in his rear view mirror from a long way off, and he will at all times have the indirectly-reflected hook image in his rear view mirror. By the time the directly-reflected approach-guidingline image disappears from his rear view mirror (i.e. if it is eventually cut off by the back end of the towing vehicle), it will have appeared, or will be about to appear, with the image of the hitch itself, as an image reflected indirectly into the rear view mirror via the convex mirror.

The trailer-mounted wand should be readily attachable to and detachable from its mounting point so as to project vertically from the hitch when the trailer is viewed from the front and from the side.

To make it easier for the driver to keep the approach-guiding-line image and the hook image vertically in line with one another as he reverses, the reflecting surface of the convex mirror may be marked with an indicating line which appears vertical when viewed in the vehicle's interior mirror, which extends down to the top and/or the bottom edge of the convex mirror, and on which the line-of-approach end-point lies.

The term "trailer" when used in this specification is intended to be given a broad interpretation and to cover any ground-travelling apparatus having a hitch which can be coupled to the hook of a towing vehicle.

Embodiments of the invention are illustrated by way of example in the accompanying drawings. They represent the best ways currently known to the applicant of putting the invention into practice. They will now be described with reference to the drawings, in which: Figure 1 shows in perspective the two implements which make up the first embodiment; Figures 2 to 2D show to an enlarged scale the construction of the convex mirror of this first embodiment; Figure 3 shows how the convex mirror is initially "sighted" in the vehicle's normal interior rear view mirror; and Figures 4, 5 and 6 show the images seen by the vehicle driver in his rear view mirror as he progressively approaches the waiting trailer.

The assembly illustrated in Figs. 1 and 2 is for use in reversing a saloon car towards the front of a waiting caravan. It consists of two implements, a vehicle-mounted implement referenced generally 11 and a caravan-mounted implement referenced generally 1 2.

The caravan-mounted implement is the simpler of the two. It consists of an elongate straight wand 1 3 projecting from one end of a horse shoe 14. Each end of the horse shoe carries a cylindrical weight referenced respectively 1 4a, 1 4b. The wand 1 3 is slender and is painted bright red.

In use, as Fig. 1 shows, the wand sits on top of and projects vertically from the partspherical cup of the hitch which is to be engaged by the ball of the vehicle towing hook. The wand 1 3 is long enough for its image to be visible, in the rear view mirror of the towing vehicle, above the back of the towing vehicle until the vehicle approaches sufficiently close to the waiting hitch for the image of the wand to be cut off by the back of the approaching vehicle.

The weights 1 4b are equal and are each equally spaced from the centre line of the wand 1 3. They keep the wand 1 3 projecting vertically upwards whether viewed from the front or the side of the caravan, whilst enabling it to be readily attached to and detached from the top of the caravan hitch.

When not in use, the wand can be carried in the boot of the towing saloon car or can be stowed in the caravan itself.

The vehicle-mounted implement 11 comprises two relatively long slender tubular rod stays 1 5 pivotally supporting a convex mirror 1 6. The stays 1 5 enter pivot holes moulded into the opposite sides of a plastics housing 1 7 to which the convex mirror 1 6 is fixed by a beading 1 6a which runs round the periphery of the mirror and is-a snap-fit in a peripheral channel in the plastics housing 1 7 as shown in Figs. 2A to 2D. The fit of the stay ends is such that the mirror housing 1 7 and its mirror 1 6 can be pivoted about the stays.It is also sufficiently tight that when the mirror has been pivoted to a desired position it can be left there and will not move from that position in normal use of the implement 11.

The ends of the stays 1 5 which do not pivotally support the mirror and housing 16, 1 7 are parallel and each enter respective bores formed in a plastics base 1 8. Two replaceable magnets 1 9 are housed in the base 1 8 and, in use, clamp the base 18 firmly but detachably to the boot lid or back of the vehicle above the towing hook in a position in which an image of the mirror 1 6 can be seen in the vehicle's normal existing interior rear view mirror. Grub screws (not shown) hold the magnets loosely inside the base 18 so that the base can seat firmly on the car body. On each side of the base 18 a circumferential succession of part-circular notches 21 is formed in a curved lip which projects from the base side. The stays 1 5 are resilient and can be flexed away from one another to disengage from one of the notches 21 and then released to snap into another notch in the series. This allows the convex mirror 1 6 to be brought above and in line with the towing hook, and held in that position.

The reflecting surface of the convex mirror 1 6 is marked, in bright red paint, with an indicating line 22. The line 22 ends at a point 23 which is marked by an enlarged circular dot of red through the centre of which a hole is drilled. The circular red dot 23 lies in the middle of a planar section of the mirror 16, whilst the line 22 for most of its length occupies a progressively curving portion of the mirror and only enters the planar portion when it has almost reached the end-point 23.

In this particular embodiment the mirror 1 6 curves around a constant radius. A notional tangent to the end of that curve (i.e. where the line 22 meets the bottom edge of the mirror 16) is angled at approximately ten degrees to the planar portion containing the dot 23.

The line 22 is straight and extends up the middle of the mirror 1 6 to the end-point dot 23.

An auxiliary mirror 23' is also carried by the housing 1 7 and forms part of the vehiclemounted implement 11. The mirror 23' is planar, square, and relatively small. It is mounted on stays 24 which are a free swinging fit in bores formed in the housing 1 7. The auxiliary mirror 23' cannot move about its stays 24, but the stays 24 are unrestrained by any friction or other clamp in their bores so that they will automatically hang vertically under gravity with the reflecting surface of the auxiliary mirror horizontal and facing the reflecting surface of the convex mirror above the towing hook at the back of the vehicle.

In use, both mirrors are mounted and adjusted to the positions shown in Fig. 1, in which when viewed from front or side they are in line with the part-spherical ball 27 of the towing hook of the car. This particular car has a so-called hatchback vertically-opening rear tailgate, and so the base 1 8 of the vehicle-mounted implement is attached to the back of the vehicle below the tailgate to allow the tailgate to open and to be left open so that its back window does not interfere with the transmission of images from the convex mirror 1 6 into the vehicle's normal interior rear view mirror.

As indicated in Fig. 1, the driver of the vehicle looks down through the hole extending through the back of the housing 1 7 and through the mirror 1 6 into the auxiliary mirror 23'. By moving the stays 1 5 around the notches 21 in the base 18, he brings the freely-hanging auxiliary mirror 23' directly above the ball 27. He then pivots the frictionally-held convex mirror 1 6 about is stays 1 5 until, looking down into the auxiliary mirror 23' through the hole in the mirror 16, he sees an image of that hole and its surrounding red dot 23 positioned in the centre of the auxiliary mirror 23'.

The driver then swings the auxiliary mirror stays 24 clockwise to bring them over the back of the convex mirror 1 6. The housing 7 is long enough for the auxiliary mirror 23' to be brought round through more than 1 80 degrees and rested on the back face of the housing 1 7. In that position the mirror 23' and its stays 24 do not interrupt the reflection of images from the convex mirror 16, and the mirror 23' is no longer interposed between the mirror 16 and the towing ball 27.

If the driver then goes round to -the front of the vehicle and takes his seat, and looks into his interior rear view mirror 28, he will see an image of the red dot 23 superimposed on an image of the towing hook ball 27. The image of the red dot end-point 23 should be exactly in the centre of the ball 27. If it is not, the driver need only pivot his interior mirror fractionally in order to superimpose the image of the dot 23 exactly in the centre of the ball 27.

Fig. 3 shows the way in which the driver sees the image of the ball 27 reflected into his rear view mirror 28 by the convex mirror 16.

The wand 1 3 projecting from the top of the hitch is also visible as an image directly reflected into the rear view mirror 28. This image of the wand 1 3 will be below the image of the mirror 1 6 containing the line 22, dot 23 and ball 27 when viewed by the driver. Fig. 4 shows the driver sees initially when he looks into his rear view mirror 28.

Reference 29 in Fig. 4 indicates the back of the car (in this particular case, the rear parcel shelf below the open tailgate).

The driver, looking forward into his rear view mirror 28 all the time, reverses his car and so steers it as to keep the directlyreflected image of the want 1 3 and the indirectly-reflected image of the indicating line 22 vertically in line with one another. Eventually, as shown in Fig. 5, as he comes close enough to the caravan, the image of the wand 1 3 in his rear view mirror will be cut off by the directly-reflected image of the parcel shelf 29 of his car. As this happens, or soon after it happens, the wand 1 3 reappears in the driver's rear view mirror, this time as an image indirectly-reflected via the convex mirror 16, and bringing with it a similarly indirectly-reflected image of the top of the hitch from which the wand 1 3 projects.

The driver continues to reverse, still keeping the image of the wand 1 3 in line with the image of the line 22.

When the image of the hitch coincides with the hole in the centre of the red dot 23, the driver applies the handbrake of his car, gets out, and goes round to the back of the vehicle to find the cup of the hitch poised directly over the towing ball 27. He can then drop the cup onto the ball, remove the wand and the two-mirror implement, couple his caravan to the car, and drive off.

Because the mirror 1 6 changes from convex to planar form, the final stages of approach of the hitch image to the mirror-marked dot 23 occur more slowly for a given constant reversing speed. This makes it easier for the driver to achieve his final positioning with absolute precision.

The bottom edge of the mirror may contact the tip region of the wand 1 3 as the vehicle comes close to the waiting hitch. The wand 1 3 will then simply be pushed backwards during the last few inches of backward movement of the car. By that stage, the driver will have the reflected image of the hitch well into view.

Claims

1. An implement to aid the driver of a towing vehicle in positioning his towing hook under the hitch of a waiting trailer, the implement comprising a generally convex mirror (as interpreted herein) with a line-of-approach end-point marked on is reflecting surface; an auxiliary mirror; means for mounting the mirrors in use, firmly but detachably on the vehicle above the towing hook and in a position in which an image of the convex mirror can be seen in the vehicle's normal interior rear view mirror; means of adjustment allowing the auxiliary mirror to be brought above and in line with the towing hook, and allowing the convex mirror to be brought above and in line with the auxiliary mirror, so that the auxiliary mirror reflects an image of the marked line-of-approach end-point, and of the normal rear view mirror, into the eye of a person looking down into the auxiliary mirror; and means holding the convex mirror in that position whilst allowing the auxiliary mirror then to be moved away into a position in which it is no longer interposed between the convex mirror and the towing hook.

2. An implement according to Claim 1 and in which the line-of-approach end-point comprises a hole in the mirror.

3. An implement according to Claim 1 or Claim 2 and in which the surface region of the generally convex mirror containing the line-of-approach end-point marking is planar.

4. An implement according to any of the preceding Claims and in which the reflecting surface of the convex mirror is marked with an indicating line which appears vertical when viewed in the vehicle's interior mirror, which extends down to the top and/or the bottom edge of the convex mirror, and on which the line-of-approach end-point lies.

5. An implement according to any of the preceding Claims and in which the means for mounting the mirrors detachably on the vehicle is magnetically attached, in use, to the vehicle body.

6. An implement substantially as described herein with reference to and as illustrated in the accompanying drawings.

7. An implement according to any of the preceding Claims in combination with an approach-guiding wand substantially as described herein with reference to and as illustrated in the accompanying drawings.