WO2018115823A1

WO2018115823A1 - Movements mechanism and article including the same

Info

Publication number: WO2018115823A1
Application number: PCT/GB2017/053777
Authority: WO
Inventors: Edward Lewis Jeans
Original assignee: Edward Lewis Jeans
Priority date: 2016-12-19
Filing date: 2017-12-18
Publication date: 2018-06-28
Also published as: GB2571047A; GB2571047B; GB201908002D0; GB201621579D0

Abstract

The invention relates to a movement mechanism and an article including the same. The movement mechanism provides controlled movement of the article and includes one or more wheels or rollers mounted in engagement with a surface, drive means, and control means are provided to allow selective and differential rotation of the one or more wheels or rollers and/or positioning of the one or more wheels or rollers with respect to the surface in order to allow the direction and/or speed of movement of the article to be controlled. In one embodiment the surface is the surface along which the article is moved or in an alternative embodiment the surface is the surface of a spherical object which, in turn, contacts with the surface along which the article is moved.

Description

Movement Mechanism and Article including the same

The invention to which this application relates is to a mechanism which allows the drive, guidance, cushioned suspension and/or steerage of an article across a surface. The mechanism is particularly, although not necessarily exclusively, of use in relation to an article which is driven and powered to move about a surface such as, for example, a wheelchair, a vehicle, lawnmower or the like.

One conventional drive and steer mechanism comprises a series of wheels and at least one of said wheels is provided to be connected to a drive mechanism whereby power is applied via the wheel to the surface, and hence the article with which the mechanism is provided is moved along the surface. Typically the driven and/or other wheels can also be provided with a steering mechanism including steering rods to allow the position of the wheels with respect to the article and surface to be selected and hence the direction of the article to be determined so that the article can be moved along the surface in required directions.

A problem with known mechanisms is that the wheels tend to be spaced apart on the frame of the article, which means that the manoeuvrability of the article is restricted due to the relatively large turning circle of the steering mechanism and/or problems with the drive contact between the wheels or rollers and the surface. Also the complication of providing the power supply to the drive is a problem. The methods employed to date have resulted in relatively cumbersome systems. A yet further problem can occur when the article is to be moved across rough or uneven surfaces and/or when moving the article up and/or down obstacles, such as kerbs. However, despite these problems, this form of mechanism has been used for many years. The aim of the present invention is to provide an alternative form of mechanism which allows the drive and manoeuvrability of an article along a surface, even a relatively compressible and/or rough surface, to be improved and achieved in a simple, efficient and relatively lightweight manner.

In a first aspect of the invention there is provided a movement mechanism for providing controlled movement of an article, said mechanism including one or more wheels or rollers mounted in engagement with a surface, and drive means to cause rotation of the one or more wheels or rollers, and wherein control means are provided to allow positioning of the drive means and/or one or more wheels or rollers with respect to an axis of the article and rotation of the one or more wheels or rollers to allow the direction and speed of movement of the article to be controlled.

In one embodiment the said axis is an axis perpendicular to the surface along which the article moves. In one embodiment the axis is the vertical axis of the article.

In one embodiment the article movement includes rotation about a fixed location without a linear movement component so as to allow the article to be rotated "on the spot".

In one embodiment, the one or more wheels or rollers are mounted for engagement with a surface along which the article is moved. In an alternative embodiment the one or more wheels or rollers are in contact with a spherical object which in turn is in contact with the surface along which the article is moved.

In one embodiment the movement mechanism allows control of the speed of movement of the article when located at or adjacent to the said axis and, if the one or more wheels or rollers are moved to be offset to the said axis, allows speed and direction of movement of the article to be controlled.

In one embodiment the movement mechanism includes at least two wheels or rollers.

In one embodiment, the control means are provided to allow selective and differential operation of the plurality of the wheels or rollers, said selective and differential movement allowing the direction of movement of the article along said surface to be controlled.

In one embodiment the movement mechanism is provided with a plurality of movement parts. In one embodiment the mechanism parts are independently controllable. In addition, or alternatively, the movement mechanism operates the respective parts in a synchronised manner.

In one embodiment the direction of movement in the forward/reverse and/or turning directions is achieved by the contact of the wheels or rollers with the surface in a manner controlled in response to a selection made by the user of the article via control means. In one embodiment the control is achieved using remote control communication.

In one embodiment the positioning of the wheels or rollers is achieved via movement of a lever arrangement. Alternatively, a drive motor is provided to allow rotation about an axis of the drive means.

In one embodiment, movement of the article along said surface is achieved by engagement of said wheels or rollers with said spherical object. Typically, said engagement imparts rotation on the spherical object, which in turn imparts movement along the surface, causing the article to move along said surface.

Typically, the location of the wheels or rollers on the spherical object at any given time is remote from the interface and contact between the spherical object and the surface along which the article is moved.

In one embodiment the angular orientation of the axis of rotation of the one or more wheels or roller is controllably positioned so as to provide a steering guidance on the movement of the article.

In one embodiment the alteration of the angle of the axis of rotation is performed in conjunction with the control of the speed of movement of the one or more wheels or rollers.

In one embodiment resilient biasing means ensure that the one or more wheels or rollers remain in contact with the surface.

In one embodiment the location of the point of contact of the one or more wheels or rollers on the spherical object is altered so as to provide control of the steerage of the movement of the spherical object and hence the movement of the article.

In one embodiment there are provided a series of guide means which retain, guide and/or control the position of the spherical object with regard to the article.

In one embodiment the guide means act as a cage or fence in which the spherical object is positioned.

In a preferred embodiment the spherical object and/or wheels or rollers are partially deformable so as to allow a form of resilient suspension to be provided to the article as it is moved along the surface and/or to allow movement over obstacles of a predetermined height, such as, for example, curbs, uneven surfaces and the like with which the spherical object may come into contact.

In one embodiment there is provided a wheel or roller for providing forward and rearward movement in a first position at the said vertical axis and which is movable to an offset position on either side of the axis for providing steering control when the article is moving in a forward or reverse direction, and rotation on the spot of the article when there is no forward or reverse movement component. In one embodiment the wheel or roller is retracted from contact with the surface when it is being moved to the different positions . Alternatively there are provided three wheels or rollers, a first mounted at the said axis and the second and third wheels or rollers offset to either side and which can be selectively moved into contact to provide a drive or steering effect, or out of contact with the said surface when it is not required to provide a drive force.

In one embodiment the drive wheel is in the form of a roller and the axis about which the same rotates is angularly adjustable with respect to the surface so as to allow steerage of the spherical object and forward or reverse directional movement to be imparted.

The article may be, for example, a wheelchair, a powered lawnmower, golf cart or any vehicle..

In one embodiment, further wheels or rollers are mounted on the article to provide stability for the same. In one embodiment, the article includes an annular member and the drive means and one or more wheels or rollers are located in the aperture of the annular member. In one embodiment, when provided, the annular member is rotatable about the spherical object. In one embodiment drive means are provided to drive the rotation of the annular member.

In one embodiment the annular member is provided with an air drive and cushion bearing between the body of the article and the annular member.

In one embodiment the height of the annular member is selectively adjustable.

In one embodiment the annular member includes one or a series of cutting members depending therefrom. In one embodiment the cutters are rotated along with, or independently of, the annular member such that a cutting operation is performed by the cutting members. In one embodiment the cutting operation is performed on vegetation such as a grass lawn over which the article is travelling.

In one embodiment downwardly depending legs of the guide means include a suspension mechanism.

In one embodiment the suspension includes a pivot connection in the leg member, which pivot is biased by a resilient means, to a default position, but pivotal movement of the bottom portion of the leg member is possible as a suspension mechanism to allow impact with an object to be taken into account.

In a further aspect of the invention there is provided a movement mechanism for an article which is movable along a surface, said movement mechanism including control means which react to a user input movement command and which selectively alter drive means to impact a drive force to one or more wheels or rollers in contact with a surface and/or the position of the said one or more wheels or rollers with respect to the surface so as to create a movement force for said article. In one embodiment the contact with said surface is via contact of the movement mechanism with a surface of a spherical object and another, spaced, portion of the spherical object is in contact with the surface along which the article moves.

In one embodiment the movement mechanism is incorporated into a vegetation cutter such as a lawn mower. In one embodiment the lawn mower is of a form which can be sat on when using the same.

The present invention therefore provides apparatus which can be used to provide a relatively smooth cushioned transport for people and/or goods and which movement can be achieved even in relatively confined environments such as in warehouses, hospitals and public transport areas as a result of the rotational movement of article being achievable on the spot about a vertical axis of the article.

Specific embodiments of the invention are now described with reference to the accompanying drawings, wherein:-

Figures l a-b illustrate an elevation of the movement mechanism in two different positions of use in according to a first embodiment of the invention.

Figure 2 illustrates an elevation of the movement mechanism according to another embodiment of the invention; Figure 3 illustrates a plan view from the base of the movement mechanism in the embodiment of Figure 2;

Figure 4 illustrates a plan view from the top of the movement mechanism in the embodiment of Figure 2;

Figure 5 illustrates a side elevation of the movement mechanism of Figures 2-4 with the cutting feature;

Figures 6a - d illustrate a further embodiment of the mechanism of the invention,

Figure 7 illustrates a further embodiment of the invention; and

Figure 8 illustrates a yet further embodiment of the invention.

Referring firstly to Figures l a-b, there is illustrated part of an article 1 which includes the article base 23 which is shown. A frame or guide means 2 and a movement mechanism 12 is provided which, in this embodiment, includes two wheels 16, 18, each controlled in terms of their position in relation to a surface 8, and controllable in terms of their speed of rotation with respect to axes 9,11 respectively. The wheels are driven to rotate by a drive means including a drive motor 31 and angular adjustment means 43 allow angular adjustment of the axes 9,11 with respect to the axis 25 of the article which is perpendicular to the surface 8 when the article is being moved therealong, and which axis is typically vertical.

For the purposes of illustration, only the movement mechanism is indicated in these figures without the remainder of the article being fitted to the base 23. Movement is provided to the article to move the same along the surface 8 by the selective operation of the wheels 16, 18 which can be selectively controlled and positioned to cause the controlled movement and steerage of the article along the surface 8.

If, from a standing position, it is desired that the article moves in a forward direction, a drive force from the drive means 31 is imparted to both of the drive wheels 16, 18 at the same time, and at the same speed and with the axes 9,11 perpendicular to the axis 25, as shown in Figure l a so as to cause the wheels to rotate at the same speed and directly onto the surface 8 so that the movement of the article across the surface is achieved. However, if it is desired that there should be movement in a curve with respect to the surface 8, then the angular adjustment means 43 are activated either manually or automatically in response to a user's control input to pivot the axes 9,1 1 with respect to the axes to apposition, such as that shown in Figure l b, such that only one of the wheels, in this example, wheel 16, is in contact with the surface 8 with the other wheel 18 pivoted away from and possibly out of contact completely, with the surface 8, As a result, the provision of drive to the wheels 16 18 results in the article to be moved in a curve. When the correct direction for linear movement has been selected, both wheels 16, 18 can then again be contacted with the surface 8 and forward or reverse motion in the linear direction achieved. In another control selection the axes 9,11 are maintained in the orientation shown in Figure l a and either the drive means 43 is rotated about the axis 25 so as to cause rotation of the wheels about the axis 25 or only one the wheels 16 or 18 is provided with drive and in either embodiment rotation of the article "on the spot" about axis 25 is achieved.

Referring now to Figures 2 to 4, there is illustrated a movement mechanism according to another embodiment of the present invention. The movement mechanism includes a frame or cage 2 within which is mounted a spherical object 4, such as an inflatable ball. In any of the embodiments the spherical object, wheels and/or rollers can be partially deformable and resilient so as to return to the preferred condition when no pressure is applied thereto. This allows the article to be movable over obstacles such as kerbs and the like.

The spherical object is free to move within the frame 2 but at any time, in use, it is typically the case that a portion 6 of the spherical object is in contact with the surface 8 along which the article is to move and a further portion or portions 10 of the spherical object is/are contacted by the one or more wheels or rollers of the movement mechanism 12. The movement mechanism 12 in this embodiment functions much in the same way as in the embodiment depicted in Figures l a-b, and the movement mechanism 12 has been reduced in size and acts upon the surface 10 of the spherical object 4 rather than directly on the surface 8, causing movement of the article therealong.

The frame 2 includes guide means 14 on leg members 15 provided on the frame at spaced locations with respect to the spherical object and, typically a distance apart from the spherical object. The guide means can be provided in any required configuration and in one embodiment can be provided as ball bearings. The leg members include a suspension mechanism as shown in Figure 2. The leg member 15 is formed of an upper, fixed, portion 15' and a lower portion 15" which is pivotably connected to portion 15' about pivot 17. The pivot is provided with a resilient means in the form of spring 19 which biases the portions to the position shown and the stop 21 prevents the portion 15" from moving inwardly. However, the portion 15" is able to move in the direction indicated by arrow 23 to allow raising or lifting of the stabilising castors 30 over an object such as a kerb or the like to be taken into account. The spring 19 causes the portion 15" to return to the position shown when the object is removed. In one embodiment, not shown, drive means can be provided in connection with each of the guide means to allow the selective powered lifting of the lower portion 15" so as to move the same upwardly out of contact with potential obstacles and then lower the same when the obstacle has been passed. Alternatively the lower portion can be manually lifted out of the way.

In one embodiment a stop is provided for the guide means lower portions so as to prevent the lower portions 15" from pivoting outwardly beyond a predefined limit. This is to prevent the centre of gravity of the apparatus from moving beyond a predefined limit and thereby act to prevent the apparatus from toppling over when traversing, for example, a bank or slope.

The lower portion 15" also includes a stabilising ball or castor 30 and in one embodiment this can also be spring loaded as shown via spring 27. The guide means 14 are positioned so as to act as a cage to retain the spherical object 4 within the confines of the frame and hence in contact with the drive means. The castors 30 are typically free wheeling and follow, rather than guide, the movement of the ball.

As an alternative to the above arrangement the portions 15" can be telescopically positioned and spring loaded towards an extended position thereby ensuring that a relatively rough surfaces the ball or castors are encourages into contact with the surface.

In this embodiment, the movement mechanism 12 comprise two wheels 16, 18, each controlled in terms of position and speed by a drive motor 20. Resilient suspension means are provided which ensure that, even if the spherical object moves position with respect to the frame 2, the wheels remains in contact with the spherical object to maintain the movement of the same when driven.

In use, with the spherical object 4 in contact with the surface 8, the movement mechanism 12 is selectively controlled and positioned to cause the wheels to rotate on the surface 10 and provide controlled movement of the spherical object, and hence article with which the same is provided, along the surface 8, and also to control the direction of movement of the article along the surface in the following manner.

If, from a standing position, it is desired that the mechanism move in a forward direction, drive is imparted to both of the drive wheels 16, 18 at the same time, and at the same speed, so as to cause the same to rotate at the same speed as indicated by arrow 22 in Figure 5. Thus rotation is imparted to the spherical object 4 surface 10 so that the spherical object rotates as indicated by arrow 24 and in turn, the rotation is imparted onto the surface 8 so that the movement across the surface is achieved as indicated by arrow 26.

However, if it is desired that there should be movement in a curve with respect to the surface then in this embodiment a wheel control means 29 is activated either manually or automatically in response to the user's requirements to act as a pivot such that only one of the wheels is in contact with the spherical object with the other wheel pivoted away from the surface 10 of the spherical object or one wheel is in greater contact with the spherical object 4 than the other. As a result, the provision of drive to one of the wheels 16,18 causes rotation of the support unit base 23 which is attached to the article and pivotally rotatable with respect to the frame 2 so as to pivot the article 23 and hence rotate about the central axis 25 of the spherical object. When the correct direction for onward or rearward linear movement has been selected, both wheels 16, 18 can then again be contacted with the spherical object and rotated at the same speed and motion in the linear direction achieved. In one arrangement a motor may be provided to rotate the support axes 9,11 of the wheels about the axis 31 so as to provide the variation in degree of contact.

Figure 5 also illustrates the embodiment of Figures 2-4 with the additional provision of a cutting means as part of the mechanism. The cutting means include an annular member independently mounted on the frame so as in this embodiment to surround the spherical object. The annular member 31 is mounted on a bearing so as to be rotatable about the axis 25. Drive means (not shown) are mounted to cause the rotation of the annular member. Depending downwardly from the annular member are a series of cutting members 33, such as, blades. The height of the bottom of these cutting members from the surface 8 can be adjusted such that if, for example, the surface is a lawn, the height of cut of the grass can be adjusted. The rotation of the annular member causes the rotation of the members 35 and hence the cutting action to be achieved. A shroud 37 shown in broken lines is typically provided to mask the annular means and top parts of the cutting members. Typically the lower portions 15" of the guide means, if provided to be movable, are provided with stops to prevent the same from being moved too far outwardly and contacting the annular ring on which the blades are provided.

In an alternative embodiment the annular ring is provided inwardly of the guide means and lies between the inner side of the guide means and the ball and therefore lies in the gap between the same. In this way the possibility of a clash with the movable guide means is avoided as they cannot move inwardly. If required, suitable grass collection means can be mounted in conjunction with the mechanism shown.

In an alternative embodiment of the apparatus, similar components as shown in Figures 6a-d are shown with the same numbering as used in Figures 1 -5. In Figures 6a— d the support unit carriage 23 and frame 2 are fixed. In this case, if movement is required to the left or right, rather than straight ahead, then if the movement is to be to the left, as indicated by arrow 128 in Figure 6c, rotation of the wheel 1 16 is provided by the drive means, however no rotation of the wheel 118 occurs. This relative movement causes rotational movement of the article in a curved path across the surface as indicated by arrow 128, and so it will be seen that the turning of the article occurs with respect to the surface 8 allowing the object to move off in any direction when both drive wheels are connected and rotated, with the spherical object.

The wheels can also be moved along the surface 10 of the ball progressively from the top towards the bottom so as to move the same from a relatively low gearing to a relatively high gearing.

Gearing of the drive can also be achieved, in another embodiment, by providing first and second wheels on a shaft, and by selectively moving the wheels towards and away from each other along the shaft and thereby altering the positon of the wheels with respect to the ball circumference.

If a more gradual turning curve 128 is required, while moving forwards or backwards across a surface 8, then some rotational drive to both of the drive means wheels can be employed differentially with respect to their speeds of rotation. Alternatively one of the drive wheels 116,1 18 may be intermittently connected and disconnected with the spherical object.

In either of the embodiments, in addition to the spherical object contacting the surface further castors or balls 30 can be provided to add further stability to the mechanism on the surface.

Alternatively, the carriage 23 can be moved to one side with respect to the spherical object 4, effectively altering the circumference of the circular path of the wheels 116, 118 on the surface 10 of the spherical object and thereby altering the gearing and speed of drive in each side of the spherical object and hence turning the article accordingly.

Turing now to Figures 7 and 8, there are illustrated two further embodiments of the invention in which, in each embodiment, the movement mechanism includes a motor 100, a drive wheel or roller 102 in contact with the surface portion 1 10 of the spherical object 104. Another portion 106 of the spherical object is in contact with the surface 108 along which an article, which incorporates the components mentioned above, is to be moved in a controlled manner.

In Figure 7 a first wheel or roller 102 is provided on a member 1 10 and includes biasing means in the form of a spring 1 12 to bias the wheel or roller 102 into contact with the spherical object surface when a forward or reverse drive force is required to be exerted on the spherical object and hence article along the surface 108. When no drive force is required the drive wheel or roller 102 can be retracted from contact in the direction of arrow 1 13 and can then be moved from the forward or reverse drive position 114 as indicated by arrow 123 to the position 1 17 or, as indicated by arrow 121 , to the position 119 and placed in contact with a different part of the spherical object surface 1 10 offset from the vertical axis 115. When the wheel or roller 102 is in the central position 114 the spherical object and hence article is moved in a forward or reverse direction along the surface 108 and when in the right 117 or left positions 1 19 and the spherical object is already moving, the spherical object is steered to the left or right respectfully. The speed of rotation of the wheel or roller 102 imparted by the motor 100 is used to control the degree of curve of movement of the article. If the spherical object is stationary when the drive is imparted by the drive wheel 102 in the position 117 or 119, then the spherical object is substantially rotated about the central axis 115 with no, or very little, forward or reverse linear component to the movement. In an alternative to that shown, rather than one positionally adjustable drive wheel 102 being provided, a drive wheel can be provided at each of the positions 1 14,117 and 119 and locating means are provided to allow the same to be selectively moved to contact the spherical object surface 1 10 in response to a particular directional control provided by the user.

In Figure 8 a roller 102 is provided on the axis 115 and the angle of the axis 120 about which the roller rotates is selectively adjustable between a position which is substantially parallel with the surface 108 along which the spherical object and article is to be moved in which case the direction of movement is forward or reverse, or moved to an angular position such as shown by axes 122,124, shown in broken lines, so as to allow the direction of movement to be curved in one direction or the other. This angular adjustment of the axis moves the point of drive contact to be offset to a side of the axis 115 allowing steering of the article in a curved manner when the article is moving backwards and forwards and rotation about the axis 115 when the spherical object is stationery. Typically, in either embodiment, guide means of the type described in the other embodiments can be used.

Thus it will be appreciated that there is provided in this invention an advantageous and improved drive steerage and suspension mechanism. In the embodiment including a spherical object the relatively large diameter of the spherical object means that the same provides a relatively large surface contact footprint which is particularly useful for traversing relatively rough or uneven surfaces. The present invention therefore allows the apparatus to be provided with a zero turning circle and allows right angled and acute angled turns to be achieved. The article can also be provided with a relatively large footprint compared to the size of the movement mechanism, thereby allowing the apparatus to be usable safely and with good stability on relatively rough terrain. This also allows the apparatus to be useful in moving over objects and the suspension provided by the wheels or rollers and ball, where provided, and/or additional suspension, ensures that this can be achieved with minimised discomfort or risk of damage. The movement mechanism can be relatively easily incorporated in to an article to allow movement of the same with the article being provided integrally with or fixed to the base and/or frame of the movement mechanism.

Claims

1. An article with a movement mechanism for providing controlled movement of the article, said mechanism including one or more wheels or rollers mounted in engagement with a surface, and drive means to cause rotation of the one or more wheels or rollers, and wherein control means are provided to allow positioning of the drive means and/or one or more wheels or rollers with respect to an axis of the article and rotation of the one or more wheels or rollers to allow the direction and speed of movement of the article to be controlled.

2. An article according to claim 1 wherein the said axis is perpendicular to the surface along which the article moves.

3. An article according to claim 2 wherein the axis is the vertical axis of the article.

4 An article according to claim 1 wherein the movement mechanism is capable of causing rotation of the article about a fixed location without linear movement

5 An article according to claim 1 wherein the speed of rotation of the one or more wheels or rollers of the movement mechanism allows control of the speed of movement of the article when located at or adjacent to the said axis and, if the one or more wheels or rollers are moved to be offset to the said axis, allows speed and direction of movement of the article to be controlled.

6 An article according to claim 1 wherein the one or more wheels or rollers are mounted for direct contact with a surface along which the article is moved.

7 An article according to any of the preceding claims wherein the movement mechanism includes at least two wheels or rollers.

8. An article according to claim 7 wherein the movement mechanism includes first and second movement parts which are independently controllable to operate on respective wheels or rollers.

9 An article according to claim 8 wherein the operation of the movement parts of the movement mechanism is synchronised.

10 An article according to claim 9 wherein the direction of movement of the article in the forward/reverse and/or turning directions is achieved by the contact of the wheels or rollers with the surface in a manner controlled in response to a selection made by the user via the control means.

11. An article according to any of the preceding claims wherein the control selection is achieved using remote control communication.

12 An article according to any of the preceding claims wherein the positioning of the movement mechanism in response to the control means is achieved via movement of a lever arrangement.

13. An article according to any of the preceding claims wherein a drive motor is provided to allow rotation of the wheels or rollers and hence movement of the article.

14 An article according to claim 1 wherein the one or more wheels or rollers are mounted for contact with a surface of a rotatable spherical object which is provided as part of the article.

15. An article according to claim 14 wherein the surface of the spherical object is in turn in contact with the surface along which the article is controlled to move.

16. An article according to claim 14 wherein there are provided a series of guide means which retain, guide and/or control the position of the spherical object with respect to the article.

17 An article according to any of the preceding claims wherein resilient suspension means urge the one or more wheels or rollers to remain in contact with the said surface during movement.

18 An article according to claim 16 wherein the guide means act as a cage in which the spherical object is positioned.

19 An article according to any of the preceding claims wherein the spherical object, when provided, and/or one or more wheels or rollers are partially deformable so as provide a resilient suspension to the article as it is moved along the surface and/or allow the capacity to move over obstacles with a predetermined height range.

20 An article according to any of the preceding claims wherein the angular orientation of the axis of rotation of the wheel or roller with respect to said surface is selectively positioned so as to provide a steering guidance for movement of the article.

21. An article according to claim 19 wherein the alteration of the angle of the axis of rotation of the one or more wheels or rollers is performed in conjunction with the control of the speed of movement of the one or more wheels or rollers.

22 An article according to any of the preceding claims wherein the location of the point of contact of the one or more wheels or rollers on the surface is altered so as to provide control of the steerage of the movement of the article.

23. An article according to claim 1 wherein the one or more wheels or rollers provide forward and rearward movement in a first position and which is selectively movable to an offset position on either side of the first position for providing steering control when the article is moving in a forward or reverse direction, and rotation when there is no forward or reverse movement.

24. An article according to claim 23 wherein the one or more wheels or rollers are retractable from contact with the surface when being moved to the different positions .

25. An article according to claim 22 wherein a first wheel or roller is provided in a first position and second and third wheels or rollers wheels are respectively offset to either side of the said first position.

26 An article according to claim 25 wherein the drive wheels are selectively retracted from contact with the surface when not required to provide a drive force.

27 An article according to any of the preceding claims wherein a roller is provided and the axis about which the same rotates is angularly adjustable with respect to the surface moves so as to allow steerage and forward or reverse directional movement to be imparted to the article.

28 An article according to any of the preceding claims wherein the article includes stabilising means to contact with the surface along which the article is moved and thereby provide additional stability to the article.

29 An article according to claim 28 wherein the stabilising means are not driven and follow the movement of the article.

30 An article according to claim 29 wherein the article is any of a wheelchair, a powered lawnmower, golf cart or any propelled vehicle.

31. An article according to any of the preceding claims wherein the article includes an annular member positioned such that the one or more wheels or rollers and drive means are located in the aperture of the annular member.

32 A movement mechanism for an article which is movable along a surface, said movement mechanism including control means which react to a user input movement command and which selectively alter drive means to impact a drive force to one or more wheels or rollers in contact with a surface and/or the position of the said one or more wheels or rollers with respect to the surface so as to create a movement force for said article.

33 A movement mechanism according to claim 32 wherein the said surface is the surface along which the article moves.

34 A movement mechanism according to claim 32 wherein the said surface is the surface of a spherical object and another, spaced apart, portion of the spherical object is in contact with the surface along which the article is moved.

35 A movement mechanism according to claim 32 wherein the mechanism includes further wheels or rollers to provide stability.

36. A movement mechanism according to claim 32 wherein the movement mechanism includes one or a series of cutting members depending therefrom and the cutters are rotated along with, or independently of, an annular member, to perform a cutting operation.