WO2005042336A1 - Biasing of wheel on towable vehicle - Google Patents

Abstract

A towable vehicle, eg a trailer, is provided with swivelling wheels (4). The axis of swivelling (15-2) of wheel (4) has a positive castor of Ø, preferably 3-5 degrees, when the vehicle is travelling in direction (13). When the towable vehicle is reserved, a powered means, which may be operated manually or by motor, is used to reverse the castor angle also so that this angle is again positive and the wheels tend to follow in the direction of travel.

Description

BIASING OF WHEEL ON TOWABLE VEHICLE

FIELD OF INVENTION The present invention relates to the field of towable vehicles, by which we mean vehicles not adapted for self propulsion. In one form, the present invention relates to towable vehicles adapted to travel on land, for example, trailers adapted to be towed by vehicles such as cars and prime movers, caravans, floats, such as horse floats, low-loaders, or any towable or moveable device not adapted for self propulsion. In a very specific form, the present invention relates to towable vehicles having wheels mounted on at least two axles. It will be convenient to hereinafter describe the invention in relation to the use of at least two axle towable vehicles, however it should be appreciated that the present invention is not limited to that use only. BACKGROUND ART Figure 1 illustrates one arrangement of the prior art. Trailer 1 has two axles, namely a forward axle 2, and a rear axle 3. Each axle has wheel(s) 4 for contact with the ground. Typically, the trailer 1 is towed by a vehicle 5, via a tow bar 7. The tow bar 7 is connected at the vehicle end by a coupling 6 and at the trailer end via a pivot point 8. The forward axle 2 is also coupled to the pivot point 8. In use, if the vehicle 5 towing the trailer 1 turns, such as around a corner, or following bend in a road, as indicated by arrows 9 and 10, then forward axle 2 must likewise turn in a direction, as shown by arrows 11 and 12, to enable the trailer to follow the vehicle 5. Whilst the vehicle is moving in a forward direction as indicated by arrow 13, this arrangement works suitably. However, the inventor has found that problems arise when the vehicle moves the trailer in a reverse direction, as indicated by arrow 14. The act of reversing a trailer in direction 14 has been found to be very difficult, and requires substantial manoeuvring of both the vehicle 5 and the trailer 1. Whilst travelling in a direction 14, the vehicle must be moved (by steering) in a direction 9, 10 opposite to the direction of movement of the trailer. This is very difficult for many people. Any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the invention. It should not be taken as an admission that any of the material forms a part of the prior art base or the common general knowledge in the relevant art in Australia or elsewhere on or before the priority date of the disclosure and claims herein. An object of the present invention is to provide a mechanism for a towable vehicle that will assist in the manoeuvring of the towable vehicle whilst travelling in a reverse direction. A further object of the present invention is to alleviate at least one disadvantage associated with the prior art. SUMMARY OF INVENTION The present invention provides, in one aspect of invention, an arrangement adapted to move the relative configuration of a wheel to its corresponding point of coupling on a towable vehicle, the arrangement comprising biasing means adapted to bias the wheel in the direction of travel relative to the point of coupling. The present invention provides, in another aspect of invention, a method of arranging a towable vehicle for travel in a forward or reverse direction, the method comprising the step of providing, in operative association with a wheel of the towable vehicle, a castor angle in one of the forward or reverse directions. The present invention provides, in a further aspect of invention, an apparatus adapted to arrange a towable vehicle for travel in a forward or a reverse direction, the apparatus comprising means adapted to operate in accordance with the method as claimed in claim 9. The present invention provides, in accordance with a still further aspect of invention, a towable vehicle comprising a frame, at least two wheels, each of which is coupled to the frame via an axle arrangement, and a tow coupling pivotally connected to the frame. Other aspects and preferred aspects are disclosed in the specification and/or defined in the appended claims, forming a part of the description of the invention. In essence, the present invention is based on realising that by providing a bias, such as a castor angle, to a wheel arrangement relative to the vertical in the direction of travel of the towable vehicle (whether in a forward or a reverse direction), a number of problems associated with the prior art can be alleviated. The present invention has been found to result in a number of advantages, such as providing a different configuration to that of the prior art, and which results in easier reversing of a towable vehicle. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF THE DRAWINGS Further disclosure, objects, advantages and aspects of the present application may be better understood by those skilled in the relevant art by reference to the following description of preferred embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and in which: Figure 1 illustrates an arrangement of the prior art, Figure 2 illustrates, differently, an arrangement of the prior art, Figures 3 and 4 illustrate an arrangement according to the present invention, Figure 5 illustrates one arrangement for moving the link, Figure 6 illustrates another arrangement according to the present invention, and Figures 7 and 8 illustrate a trailer arrangement according to another aspect of invention. DETAILED DESCRIPTION In describing the present invention, it will be helpful to understand a prior art arrangement first. Figure 2 illustrates, differently, an arrangement of the prior art. A wheel 4 is mounted on an axle 2. The axle 2 is fixed to a vehicle (not shown) at point 15 via a link 16. A line 17 indicates the vertical relative to the ground 18. It can be seen that the axle 2 is not provided in a direction vertical relative to point 15. In other words, axle 2 is not mounted along a vertical axis 17 of point 15. The axle 2 is provided forward of the vertical 17 (of point 15) at a castor angle 0. Referring to Figure 3, which illustrates an arrangement of the present invention, the arrangement shown is somewhat similar to that of Figure 2, except that the link 16 is moveable, as indicated by arrow 19, relative to the vertical 17. In other words, in accordance with the present invention, if the towable vehicle is to travel in a forward direction 13, the castor angle 0 is provided forward (in the direction of travel 13) relative to the vertical 17. Referring to Figure 4, which also illustrates the arrangement of the present invention, except that Figure 4 illustrates the arrangement adapted for travel in a reverse direction 14. The link 16 is arranged in a manner that provides the castor angle 0 in the direction of travel, but now the castor angle is provided in a direction 14, relative to vertical 17. The castor angle 0 must be greater than zero degrees. The angle is most preferably greater than zero and up to 20 degrees, preferably 3 to 5 degrees. Figure 5 illustrates one preferred arrangement for moving the link 16 in the desired direction of travel of the towable vehicle. The link 16 may be moved by attachment 20. The attachment 20 is coupled at one end 21 to the link 16, and at it's other end 22 to a suitable means for movement, such as in a direction indicated by arrow 23. Attachment 20 may be actuated mechanically, for example by a handle (not shown) which is moved into the appropriate position by an operator prior to travel in a direction 13 or 14. Alternatively, the attachment may be actuated by an electro-mechanical means, such as by a suitable motor and linkage arrangement (not shown). The motor may be arranged to provide the castor angle as shown in Figure 3, however, when a vehicle is about to travel in a reverse direction, the motor (or its associated circuitry) may sense a reverse signal from a the vehicle, such as from the reversing lights or signal mechanism commonly installed on self-propelled vehicles. Figure 6 illustrates another arrangement according to the present invention. In this arrangement, the distance between the axle 2 and the mounting point 15 (of Figures 3 and 4) is greatly reduced. A wheel 4 with an axis of rotation 2, is provided within or in close proximity to mounting point 15. The mounting point 15 may be an axle arrangement. The mounting point 15 is adapted to rotate in the direction indicted by arrow 19, to provide the castor angle 0 as described above. Figure 7 illustrates, in plan view, a trailer arrangement according to another aspect of invention. The trailer has a frame 70, and at least two axles 71 and 72 upon which wheels 73 are mounted. The axle 71 is provided rear of the trailer, and axle 72 is provided forward of the trailer. Alternatively, the axles may be provided either side of a centre part of the trailer. At the head of the trailer, there is a tow coupling 74, which may be of an A-frame or rod type structure. The tow coupling 74 is used to couple the trailer to a vehicle (not shown), so the trailer can be towed in either a forward direction 76 or reverse direction 77. The coupling is attached to the frame of the trailer at point(s) 75. Alternatively, the coupling may be to a single point of the trailer, such as when a rod type coupling is used (not shown). None, either or both axles 71 or 72 may have the castor arrangement as described above in relation to the other aspect of invention. Where the castor arrangement is used, the trailer also has recesses 78, 79 which are provided to enable the wheels 73 of axle 72 to turn in a direction as determined by the vehicle (not shown) towing the trailer. As can be seen in Figure 8, the tow coupling 74 is pivotally attached to the trailer frame at point(s) 75. This enables the tow coupling to be pivoted around point(s) 75 as indicated by arrow 80. While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth. As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood that the above described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims. Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims. Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures. For example, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface to secure wooden parts together, in the environment of fastening wooden parts, a nail and a screw are equivalent structures. "Comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof."

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An arrangement adapted to move the relative configuration of a wheel to its corresponding point of coupling on a towable vehicle, the arrangement comprising: biasing means adapted to bias the wheel in the direction of travel relative to the point of coupling.

2. An arrangement as claimed in claim 1 , wherein the bias is represented by a castor angle.

3. An arrangement as claimed in claim 2, wherein the castor angle is greater than zero degrees.

4. An arrangement as claimed in claim 2 or 3, wherein the castor angle is preferably in the range of greater than zero degrees to twenty degrees and most preferably between three and five degrees.

5. An arrangement as claimed in any one of claims 1 to 4, wherein the bias is provided by a moveable attachment.

6. An arrangement as claimed in claim 5, wherein the moveable attachment is operatively associated with the wheel.

7. A towable vehicle including the arrangement of any one of claims 1 to 6.

8. A towable vehicle as claimed in claim 7, wherein the towable vehicle is one of a trailer, caravan, horse float, boat trailer or any type of trailer towed behind a vehicle.

9. A method of arranging a towable vehicle for travel in a forward or reverse direction, the method comprising the step of: providing, in operative association with a wheel of the towable vehicle, a castor angle in one of the forward or reverse directions.

10. An apparatus adapted to arrange a towable vehicle for travel in a forward or a reverse direction, the apparatus comprising means adapted to operate in accordance with the method as claimed in claim 9.

11. A towable vehicle comprising: a frame at least two wheels, each of which is coupled to the frame via an axle arrangement, and a tow coupling pivotally connected to the frame.

12. A towable vehicle as claimed in claim 11 , wherein the tow coupling is an A- Frame.

13. A towable vehicle as claimed in claim 11 , wherein the tow coupling is a coupling rod.

14. In combination, a towable vehicle as claimed in any one of claims 7 or 8, and claims 10, 11 or 12.