TITLE WHEELED VEHICLE
FIELD OF THE INVENTION
This invention concerns vehicles which are supported by wheels. More particularly, it concerns lan vehicles with a central driving wheel, a forward steerable wheel, and a plurality of supporting or stabilising castor wheels. BACKGROUND ART
Cycles of many forms have been developed over the years. The stable tricycle has been adapted to many uses, including a child's means of transport and as a means for transporting goods and people. The less stable bicycle - in its many designs - is a common form of personal transport. The unstable unicycle remains essentially a novelty piece of equipment for use by entertainers in a circus or the like.
The bicycle and the tricycle are usually thought of as being propelled by a pedalling action of its rider, but motorised versions of the bicycle and tricycle are also well known. No instance of a motorised unicycle is known to either of the present inventors.
It is generally appreciated that the unicycle, although difficult to ride, is a very manoeuvrable vehicle. Indeed, its manoeuvrability is part of its appeal to circus audiences.
It is an object of the present invention to provide a vehicle, primarily for recreational purposes, which has a manoeuvrability which approaches that of the unicycle, but which is basically a stable vehicle and, therefore, is easy to ride.
DISCLOSURE OF THE PRESENT INVENTION
The abovementioned objective is achieved by providing a body structure around a unicycle, supporting the body structure on a number of castor-type wheels to
hold the unicycle upright and provide inherent stability of the body structure, and including a steerable wheel (supported on the body structure) to provide directional control for the vehicle so produced. The body structure may be simply a rigid frame. However, whether the vehicle is to be used as a child's toy or as an amusement vehicle for adults, it is preferable to form the body structure as a moulded body of a strong plastic material (for example, polyethylene or a polycarbonate), with provision for a rider's seat and a steering wheel or handle to control the position of the steerable wheel. In this way, a robust, but attractive and colourful, vehicle can be produced at a relatively low price. Normally the vehicle of the present invention will be propelled by pedals connected directly, or through a gear box, to the central driving wheel of the vehicle. However, it will be appreciated that the driving wheel may be rotated about its axle by a motor which is mounted on the body structure.
For full manoeuvrability, each supporting or balancing wheel must be a castor wheel, or must be mounted on the body structure to rotate freely about a respective vertical axis as well as about its horizontal axle. As will be shown below, two supporting wheels are adequate for the present invention, but it has been found that three supporting wheels provide a particularly stable, and easy to control, vehicle for use by a child.
Thus, in its broadest form, the present invention provides a vehicle comprising a ) a body structure ; b ) a driving wheel mounted centrally on said body structure ;
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c) a steerable wheel located forward of said driving wheel and spaced therefrom, and means mounted on the body structure to control the position of said steerable wheel; d) a plurality of supporting wheels mounted on said body structure and spaced from each other and from said driving wheel and said steerable wheel, each said supporting wheel being mounted so that it can rotate about its horizontal axle and its horizontal axle is rotatable about a respective vertical axis; and e) means to rotate said driving wheel about its horizontal axle. An embodiment of the present invention will now be described, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a preferred embodiment of the present invention in the form of a pedal-powered vehicle. Figure 2 is a side view of the embodiment of Figure 1, but with a different body shape.
Figure 3 is a bottom view of the embodiments of Figures 1 and 2.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS Each of the vehicles illustrated in the accompanying drawings has a moulded body structure 10 on which are mounted a driving wheel 11, a steerable wheel 12, two front castor wheels 13 and a single rear castor wheel 14. The steerable wheel 12 has its axle connected to a bracket 12A at the lower end of a steering post 16 which is located in, and supported by, a bush 16A (typically of nylon or other low friction material) that is connected to the body structure 10. The steering post 16 can rotate
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within bush 16A. Control of the position of the steerable wheel 12 is effected by a steering wheel or handlebar arrangement 17 at the upper end of the steering post 16.
The castor wheels 13 and 14, in conjunction with 5 the steerable wheel 12, support and balance the body structure 10 (and the whole vehicle). The castor wheels also permit the vehicle to move in any direction, and to rotate about the point of contact between the driving wheel 11 and the ground. Although a basic form of castor
10 wheels 13, 14 is illustrated in the drawings, it will be appreciated that other castor wheel configurations can be used.
The minimum requirement of the vehicle of the present invention is one pair of castor wheels, mounted
15 on the body structure 10 so that they are rearward of the central driving wheel 11, and their respective mounting
•r structures can rotate about vertical axes which are located approximately at the points marked "P" in Figure 3. The present inventors have found, however, that the
20 provision of three, substantially equi-spaced, castor wheels 13, 14, as shown in the drawings, avoids the possibility of the vehicle being tipped (by the distribution of the weight of the rider on the body structure) about the imaginary line joining the points of
25 contact with the ground of steerable wheel 12 and one of the castor wheels 13. Thus the illustrated form of the present invention provides a more stable, and thus a safer, vehicle for use by children.
The driving wheel 11 is mounted centrally on the
30 body structure 10. Because it provides the means for propelling the vehicle, it has to have a rim which will not slip on the ground when a force is applied to the driving wheel 11 to rotate it about its axle. If the vehicle is designed for a small child, the rim of the
35 driving wheel 11 can be made from a plastic material, but
if the vehicle is to be used by a large child or by a adult, the wheel 11 is preferably provided with a rubber rim, and more preferably the wheel 11 will be fitted with an inflatable rubber tyre. The rim of the steerable wheel 12 should also be of a material which has a significant coefficient of friction relative to the ground.
In the illustrated embodiments of the present invention, the driving wheel 11 is turned by applying a force to pedals 15 which are mounted on conventional pedal arms 19 that are fixedly attached to the driving wheel 11. The use of pedals in this manner is conventional practice. It will be appreciated by those of ordinary skill in this art that an internal gearing could be used in the hub of wheel 11, thus making the ratio of pedal rotations to rotations of wheel 11 different from 1:1. Other variations in construction that could be incorporated in connection with the driving wheel 11 include the provision of a free-wheeling hub, an external brake for the wheel 11 and a wheel mounting arrangement including compressible pads or springs.
It will also be appreciated that instead of providing pedals 15, a small motor may be mounted within the body structure 10 to rotate the driving wheel 11. Any suitable form of motor can be used, but a battery-powered electric motor is preferred. The motor can be connected to the driving wheel by any conventional manner, including a chain-and-sprocket wheel arrangement, a geneva mechanism (not preferred), or frictional contact between a rotating shaft and the rim of wheel 11. The speed of such a motor drive for wheel 11 may be controlled in a conventional manner using a throttle control lever or the like which is mounted on the top of the body structure 10. Alternatively, a control lever may be positioned on the steering wheel or handlebar arrangement 17, or the motor
control mechanism may comprise a foot-operated device, incorporated into the foot supports that will be affixed to (or formed integrally with) the body structure 10 since the pedals 15 will be omitted. The body structure 10 of the embodiment of Figure 1 is provided with means to support a seat or saddle 18 at a height selected from the range of seat heights that is available using a simple height adjustment arrangement. The embodiment of Figure 2 has a saddle or seat 18A formed integrally with the body structure 10.
When the illustrated form of the present invention is pedalled, the vehicle will perform like a bicycle when it is travelling at low speeds and is steered to follow a large radius turning circle. That is, at low speeds, the driving wheel 11 will follow the steerable wheel 12. At relatively high speeds, however, or when the vehicle is s _t*eered in a tight turning circle (or is steered to follow a rapidly varying path) , the vehicle can be rotated about the point of contact between the rim of the driving wheel 11 and the ground. Thus, the vehicle of the present invention can be used for amusement purposes in a manner which is similar to the way in which the "dodgem cars" or
"bumper cars" are used at a fairground.
INDUSTRIAL APPLICABILITY The major use of the present invention will be as a child's toy, and as an amusement vehicle for entertainment purposes.
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