EP0376970A1

EP0376970A1 - Vehicle moving apparatus

Info

Publication number: EP0376970A1
Application number: EP88907153A
Authority: EP
Inventors: Ian Arthur Royle
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-07-24
Filing date: 1988-07-22
Publication date: 1990-07-11
Also published as: WO1989000937A1; EP0376970A4; DK19190A; NZ225514A; CN1013845B; JPH03500517A; FI900354A0; DK19190D0; CN1031972A

Abstract

L'appareil décrit, qui sert à déplacer un véhicule, comprend des roues contrarotatives (12, 23, 24, 34, 41, 53) et des cylindres (14, 21, 22, 38, 42, 52) ayant des axes espacés pour permettre aux cylindres (14, 21, 22, 38, 42, 52) de s'appliquer contre une surface périphérique d'une roue de véhicule (16, 19, 39, 54, 61), les roues (12, 23, 24, 34, 41, 53) se trouvant en contact avec le sol. Un organe d'entraînement permet aux roues (12, 23, 24, 34, 41, 53) et aux cylindres (14, 21, 22, 38, 42, 52), qui sont portés par une structure de support appropriée (26, 33), de se caler contre la roue du véhicule et de lui imprimer une force d'entraînement.The apparatus described, which is used to move a vehicle, comprises counter-rotating wheels (12, 23, 24, 34, 41, 53) and cylinders (14, 21, 22, 38, 42, 52) having spaced axes for allowing the cylinders (14, 21, 22, 38, 42, 52) to press against a peripheral surface of a vehicle wheel (16, 19, 39, 54, 61), the wheels (12, 23, 24 , 34, 41, 53) being in contact with the ground. A drive member allows the wheels (12, 23, 24, 34, 41, 53) and the cylinders (14, 21, 22, 38, 42, 52), which are carried by an appropriate support structure (26, 33), to wedge against the vehicle wheel and impart a driving force to it.

Description

VEHICLE MOVING APPARATUS Field of the Invention

This invention relates to vehicle moving apparatus and relates particularly to apparatus operable to move wheeled vehicles from one place to another.

The invention is particularly suitable for the movement of aircraft but may also be used for the movement of any other wheeled vehicle including automobiles, trucks, wheeled transport vehicles of all types, rail vehicles and the like. For purposes of simplicity, the invention will be described with regard particularly to the movement of aircraft. Background of the Invention

To move a vehicle from one place to another it is generally necessary to utilize the vehicle's own propulsion means or to use auxiliary towing means which can be detachably connected to the vehicle to be moved.

Auxiliary towing machines used for relatively large aircraft, such as used at international airports, e relatively expensive. Such towing vehicles, or tugs, are used to move aircraft in and out of loading bays as well as for movement of aircraft around tarmac areas for maintenance and other purposes. Because of the cost of such towing vehicles, delays can occur when vehicles are not available at particular times.

Towing vehicles, prime movers or "tugs" can only move a vehicle, such as an aircraft, if the horizontal, ground contact forces developed between the tug and the ground exceed the horizontally opposed frictional and other forces developed by the vehicle to be moved. These forces are a function of the weight of the tug, the power delivered to the ground engaging wheels and the coefficient of friction existing between the wheels of the tug and the ground. In instances where an airport tarmac is covered with water or ice, it may be extremely difficult, if not impossible, for the tug to develop sufficient force to move a parked aircraft, particularly if the aircraft has been parked for some time resulting in "setting" of the tyres with a flat spot at the ground contact area.

The use of ground tugs at airports also generally requires the use of at least three personnel, a driver of the tug and two observers. In some cases, additional staff are required to assist in placement of the ground tug drawbar, removal of aircraft chocks and the like. The requirements for such numbers of ground staff adds to the cost of operation of an airport.

At airports which handle light aircraft, such aircraft are generally moved manually when not under power. In some instances of maintenance, it is often necessary to move an aircraft into and out of a hangar a relatively large number of times to complete all the maintenance requirements and to facilitate movement of other aircraft into and out of the maintenance hangar. Each movement of the aircraft requires personnel and involves danger of damage to the aircraft by contact of wing tips with hangar structures and the like. Also, the use of known tugs or prime movers within hangars gives rise to pollution which is to be avoided if possible. Background Art

Australian Patent No. 519,027 to Societe Anonyme Secmafer discloses a modified form of aircraft towing vehicle having a platform which receives the nose wheel unit of the aircraft to be moved. The platform extends as an inclined plane forming an access ramp for the nose wheel unit. The ramp is articulated and hydraulic jacks enable the inclined plane to be lowered and raised.

Use of this type of vehicle requires lifting the nose wheel unit, and, consequently, the front of the aircraft. With large aircraft, the mass to be lifted onto the vehicle is relatively high. Also, the vehicle must be constructed so as to be able to support the aircraft weight normally carried by the nose wheel unit. It is therefore desirable to provide apparatus for moving vehicles, such as aircraft, which avoids or at least ameliorates at least some of the disadvantages of known vehicle moving apparatus. It is also desirable to provide vehicle moving apparatus which is relatively economical to manufacture and is relatively simple to use.

It is also desirable to provide apparatus for moving vehicles which may be used on any surface on which the vehicle is located.

It is also desirable to produce vehicle moving apparatus which may take various forms depending on the end use and the vehicle type to be moved. Summary of the Invention

According to one aspect of the present invention there is provided apparatus for moving vehicles having at least one ground-engaging vehicle wheel comprising at least one rotatable ground-engaging wheel means, at least one vehicle wheel-engaging drive means, and means for rotating said wheel means and said drive means in opposite directions.

According to a further aspect of the present invention there is provided apparatus for moving a vehicle which is supported on wheels comprising a pair of rotatable drive means engageable with at least one vehicle wheel, at least one ground-engaging wheel means, first propulsion means to move said ground-engaging wheel means to cause one of the drive means to frictionally engage the vehicle wheel, second propulsion means to rotate the said one drive means in a direction opposite that of the wheel means whereby to drive the vehicle wheel.

In one form of the invention adapted particularly for the movement of aircraft, drive rollers are engaged with the surface of the aircraft wheel tyre at the front and rear thereof and ground-engaging wheels associated with each of the drive rollers, but having spaced axes, engage the ground at the front and rear of the tyre. Each ground-engaging wheel is associated with a drive roller and each ground-engaging wheel is rotated in a given direction while the drive rollers rotate in the opposite direction at a relative speed which is a function of the respective diameters of the ground-engaging wheels and drive rollers. The drive roller at the rear of the wheel is caused to move into frictional engagement with the wheel to apply a driving force thereto by the frictional contact thus causing the vehicle wheel to rotate. As the wheel rotates, the drive apparatus moves along the ground and maintains the frictional contact. If the driven wheel tends to overrun the rear drive roller, the frictional contact on the front drive roller increases thereby maintaining a substantially constant rate of movement.

By providing counter-rotating drive means engaging with the vehicle wheel to drive the wheel to be rolled and ground-engaging wheels to drive on the ground surface, and with one system located behind the vehicle wheel and one system in front, the moving apparatus can be used to move the vehicle wheel in either direction and to act as a brake for the moving vehicle.

If desired, guide rollers may be provided to engage the sides of the vehicle wheel to thereby locate the moving apparatus relative thereto. Such guide rollers may also assist in steering, as will become apparent from the following description.

Embodiments of the invention may be constructed with pairs of ground-engaging wheels and vehicle drive means carried on a frame having pivotal "sections which allow one of the pair to engage in front of the vehicle wheel with the other pair pivoted around to engage behind the wheel. The frame may have hydraulic cylinders and/or locking means whereby the pairs at the front and rear of the wheel are moved towards each other thereby squeezing the wheel therebetween to apply the necessary driving forces to the surface of the wheel and the ground. It will be appreciated that on counter-rotation of the respective drive means and ground-engaging wheels, a wedging action occurs on the rearward pair whereby the load on the vehicle wheel is transferred through the drive means to the ground-engaging wheel and to the ground. If desired, hydraulic or other locking means on the frame can act to move the opposed pairs towards each other to such an extent that the vehicle wheel is substantially lifted from ground contact whereby the weight of the vehicle supported on that wheel is partially or totally carried on the ground-engaging wheels of the moving apparatus.

The vehicle moving apparatus of the invention is relatively compact and may be produced at a substan¬ tially lower cost than the known aircraft "tugs". Because of the lower cost, a vehicle moving apparatus in accordance with the invention may be provided for each aircraft terminal gate so as to be dedicated to aircraft using the individual gates. Being dedicated, there is a big safety advantage in an emergency situation, such as in the event of a fire, as all aircraft can be moved quickly to a safe location without having to wait for one of the air terminal tugs.

Further, being dedicated, the aircraft moving apparatus of the invention may also be used as a wheel chock. Chocking of the aircraft cannot, therefore, be overlooked by ground crew.

In accordance with another aspect of the invention there is provided a transporter for moving vehicles having at least one ground-engaging vehicle wheel comprising at least one rotatable ground-engaging wheel means, at least two vehicle wheel engaging rollers or wheels to engage the vehicle wheel in front and behind, and means to drive the ground-engaging wheel means. With this arrangement, the ground-engaging wheel means is relatively large and the two rollers or wheels which engage the vehicle wheel apply a horizontal force to that wheel to initiate movement. The frictional contact causes a wedging action between the vehicle wheel and the engaged roller or wheel which causes a downward force on the wheel means thus increasing the frictional contact with the ground.

In order that the invention will be more readily understood, embodiments thereof will now be described with reference to the accompanying drawings. Description of the Drawings

Figure 1 is a schematic side view illustrating a vehicle moving apparatus in accordance with one aspect of the invention, Figure 2 is an end view of the apparatus of Figure

1,

Figure 3 illustrates, in schematic side view, a further embodiment of the invention.

Figure 4 is a front view of the embodiment of Figure 3,

Figure 5 is a top plan view of the embodiment of Figure 3,

Figure 6 is a top plan view of a further embodiment of the invention, Figure 7 is a top plan view illustrating a further modification, and

Figure 8 illustrates a contoured driving roller in accordance with an aspect of the invention. Description of Preferred Embodiments Referring to Figures 1 and 2 of the drawings, there is illustrated a vehicle moving apparatus which comprises a pair of groups- of counter-rotating wheels 12 and 1 which are mounted side-by-side and on axes spaced apart at least vertically. The groups of wheels 12 are ground-engaging while the groups of wheels 14 are carried above the ground and are adapted to engage the surface of a tyre 16 of a vehicle to be moved, such as the nose wheel tyre of an aircraft.

The two pairs of counter-rotating wheels 12 and 14 are positioned in front and behind the tyre 16. If desired, additional guide rollers 17 may be provided at the sides of the tyre 16 to accurately position the pairs of counter-rotating wheels 12 and 14 centrally relative to the tyre 16. The pairs of wheels 12 and 14 are carried by and rotatably mounted on a support framework or the like enabling the pairs of wheels 12 and 1 to be moved into and maintained in the positions shown. In one support arrangement, a common axle passes through each group of wheels 12 and 14, the axle being provided with gears to mesh directly with, for example, the wheels 12 and there being provided intermediate gears to convey motion from the axle to the other wheels 14 so that they rotate in the counter direction.

In another support and driving arrangement, adjacent wheels are interconnected to each other by internal bevelled gearing so that, rotation of an end wheel 12 directly rotates the next wheel 14 in the opposite direction which is directly connected, and rotates the next wheel 12, and so on through the group.

In an alternative drive arrangement, the wheels 12 are hydraulically or electrically driven in one direction while the wheels 14 are hydraulically or electrically driven in the opposite direction. With this arrangement, each wheel of each group may be separately driven, and separately controlled so that the wheels at one end of a group can be rotated at a speed greater than the wheels at the other end of the group thereby effecting a turning motion of the wheels and turning the tyre 16.

In operation of the apparatus of this embodiment, the groups of wheels 12 are rotated, for example, in the direction of the arrows A shown in Figure 1 and the groups of wheels 14 are rotated in the opposite direction as indicated by the arrows B. The right hand group therefore moves to the left, as shown in Figure 1 , resulting in a wedging action between the wheels 14 and the tyre 16 and producing a downward force on the wheels 12. This wedging effect together with the rotation of the wheels 14 causes the tyre 16 to rotate in the direction of the arrow C thus moving the wheel, and the associated vehicle, in the direction of the arrow D.

The left hand groups of wheels 12 and 14 assists in the rotational movement of the tyre 16 while moving to the left at the same rate as the right hand group.

The movement of the vehicle wheel and tyre 16 can be retarded by applying a retarding force. to the left hand group which slows the relative rotation and, as the tyre engages with greater force on the wheels 14, acts to retard movement of the tyre 16.

In one form of the invention, the groups of wheels 12 and 14 are driven electrically or hydraulically and the acceleration and de-acceleration rates are controlled to prevent the possibility of the tyre 16 from "jumping" over, the retarding wheel group. However, it will be appreciated that the relative size of the wheel groups and the tyre 16 will also have an affect on the accelera¬ tion- and de-acceleration rates. If desired, additional feed and guide rollers may be provided to sense any tendency of the tyre 16 to jump and thereby automatically promote corrective changes in the acceleration or de-acceleration rate to obviate the potential difficulty.

Although the wheels of the groups 12 and 14 are shown as abutting in Figure 2, it will be appreciated that the wheels of the groups may be spaced and may be assembled in a different configuration to that illustrated. Provided sufficient area of contact with the ground and with the vehicle tyre is obtained, any suitable arrangement of relationship between the counter-rotating wheels may be used.

It will also be understood that the group of counter-rotating wheels 12 and 14 which are used as the breaking wheels during the movement of the vehicle wheel in- one direction will be the driving wheels when moving the vehicle wheel in the opposite direction.

Referring to the embodiment shown in Figures 3, 4 and 5, aircraft nose wheel assemblies are often provided with dual wheels and tyres 19. In this embodiment, two, co-axial rollers 21 are located in front of the tyre 19 and a second pair of co-axial rollers 22 are located behind the tyres 19. The pairs of rollers 21 and 22 are supported above the ground by substantially co-axial pairs of wheels 23 and 24, respectively. The pairs of wheels 23 and 24 are interconnected by a beam member 26 on either side which acts to space the pairs of wheels 23 and 24 and the associated pairs of rollers 21 and 22. The beam members 26 are preferably adjustable so as to adjust the apparatus for different vehicle wheel sizes, and are able to be locked in the driving. Further, as shown in Figure 5, the beam member 26 on one side is formed in two parts which are hinged together at a pivot 27 which allows the pairs of wheels 23 and 24 to be moved from the assembled position shown in Figure 5 to a substantially co-axial, transport position whereby the apparatus is moved to and from its operative position. If desired, the pivot 27 may be arranged so that the pairs of wheels 24 are lifted from the ground when in the position substantially co-axial with the wheels 23. Thus, the driving movement of the wheels 23 in the transport position effects the movement of the apparatus.

Guide rollers 28 mounted on arms 29 extending from the beam members 26 engage the sides of the tyres 19 to centralize the location of the apparatus relative to the wheels and tyres 19. In operation, hydraulic, electric or other drive means is applied to the rollers 21 and 22 and pairs of wheels 23 and 24 so that the associated rollers 21 and wheels 23 counter-rotate as do the associated rollers 22 and wheels 24, in a manner similar to that described in the previous embodiment. The relative speed of counter-rotation is determined as a function of the respective roller and wheel diameters. The counter-rotation and the action of the frictional engagement of the rear pair of rollers 22 with the tyre 19 results in the wedging effect which acts to impart a downward load from the tyres 19 to the driving pair of wheels 23/24.

The dual wheels and tyres 19 may be steered by varying the speed of the co-axial driving wheels 23/24 to effect "skid turn" steering. With appropriate in¬ dependent control of each wheel of each pair 23 and 24 by using electrical or hydraulic driving means, the speed and direction of rotation can be simply governed. Appro- priate automatic control using a micro-processor or computer system and appropriate software can ensure that both the wheels of each pair 23 and 24 and the rollers of each pair 21 and 22 can be driven separately as necessary to effect the desired movement of the wheels and tyres 19.

Referring to Figure 6 there is illustrated a further embodiment of the invention for use with a single wheel and showing the manner in which the apparatus may be moved by an operator using a handle 31 connected by stem 32 of an appropriate length to a yoke 33 attached to one pair of co-axial wheels 34. The handle 31 may include control levers 36 of the "dead mans handle" type as well as control buttons 37. If desired, the handle 31 may be mounted on a wheeled platform (not shown) on which the operator can stand.

A roller 38 is carried by the wheels 34, in a manner similar to the previous embodiment, and engages with the surface of the aircraft tyre 39. The roller 38 is driven to rotate counter to the rotation of the wheels 34, and at a slower speed, so as to impart a driving motion to the tyre 39, in the same manner as described above. A second pair of wheels 41 carrying a second roller

42 is arranged to engage the opposite side of the tyre 39. Hydraulic or electric drive motors and gear boxes

43 are associated with each pair of wheels 34 and 41 to impart driving motion thereto and to the associated rollers 38 and 42. The respective pairs of wheels and motors 43 are interconnected by inter-engaging frame members 44 and 46 which are provided with longitudinally extending guide ways (not seen) to allow longitudinal relative movement therebetween in the direction of the arrow E but inhibiting any rotational or relative lateral movement. A slot 47 is formed in the frame member 44 and a pin 48 is carried by the frame member 46 to pass through the slot 47. On full extension of the frame members 44 and 46 relative to each other, the guide ways are dis-engaged and the members can then pivot relative to each other about the pin 48 as shown by the arrow F. The second pair of wheels 41 , associated roller 42 and its hydraulic motor 43 are moved away from the front of the tyre 39 to a transport position whereby the apparatus can be moved to and from an appropriate wheel location. Hydraulic cylinders 49 and 51 are operable to effect the longitudinal and rotational movements of* the frame members 44 and 46 relative to each other.

Referring to Figure 7 there is schematically illustrated, in plan view, vehicle moving apparatus showing ground-engaging wheels 53 which are pivotal on a supporting frame (not shown) to the position shown, or to other positions to effect steering of the dual vehicle wheels

54 during movement thereof. Guide rollers 56, also carried by the frame, press on the sides of the vehicle wheels

54 so as to cause the wheels 54 to turn about their centre support 57 to thereby take up the desired position for movement of the vehicle. The drive rollers 52 which act on the vehicle wheels for movement 'thereof as well as the wheels 54 may be rotated at varying speeds to assist in the turning movement.

The material from which the surfaces of the ground- engaging wheel and/or the vehicle wheel engaging rollers are formed may be selected commensurate with the surface on which the apparatus is to operate and the type of vehicle wheel to be moved. A ceramic sintered metal drive roller or a metal roller having a coarse stud pattern may be used to provide sufficient frictional contact between the drive roller and the surface of the vehicle tyre. Alternatively, the drive roller may be formed with a surface similar to that of a grinding wheel. If desired, the roller can have a grooved surface or be formed of an impregnated composite material, an open ceramic material, a wire brush material with compact metal fibres, or a metal sinter with an impregnated water-base solution to automatically release any rubber particles which might impregnate the roller surface.

In another construction, the drive rollers may be made of a plurality of thin discs mounted substantially co-axially but relatively movable to effect a self-cleaning movement. Such discs may be formed with appropriate edge formations to assist the gripping of the vehicle tyre. Similarly, the ground-engaging wheels may be formed of any suitable material such as hard rubber, impregnated composite material, metal, sintered metal, metal fibres or even be formed with a pneumatic tyred surface. As previously indicated, the apparatus may be driven hydraulically or by electric motors deriving power from batteries or a connection to a mains power source. The drive is preferably controlled, as indicated above, to permit even acceleration and de-acceleration to prevent a vehicle wheel jumping over a roller. Alternatively, the wheels and rollers may be driven by shaft gears, chain drive, toothed belts, torque converter means or the like. Preferably, a differential action is provided to enable one ground-engaging wheel to drive at a different rate to another to effect steering. Where the apparatus is to be used on differing surfaces such as concrete, bitumen, ice and snow and the like, the tread material for the ground-engaging wheels and for the wheel-engaging rollers may be changeable. In ice and snow conditions, two of the units may be needed to move a large aircraft, for example, and the apparatus should be designed to enable its use on main landing wheels of aircraft as well as the usual nose wheels

To ensure sufficient frictional force is applied between the drive rollers and the wheel to be driven, hydraulic or electrically actuated means are preferably provided to "squeeze" the driven wheel between the drive rollers thereby ensuring sufficient frictional force and downward force on the drive wheels. If desired, the driven wheel can be lifted substantially free of the ground so that the full weight is carried on the drive wheels in especially difficult situations such as on slippery surfaces and the like.

Further, it -is envisaged that the apparatus may be useful when the roller is not driven but is allowed to free-wheel against the vehicle wheel with the ground- engaging wheels causing a wedging action to transfer weight from the vehicle wheel to the ground-engaging wheels thereby facilitating movement. With this arrangement, which may be particularly suitable for rough surfaces such as grass and the like, the free-wheeling roller forms a wedge to push the vehicle wheel.

In another arrangement shown in Figure 8, each wheel-engaging roller 61 may be flanged and/or so shaped, as shown in Figure 8, to conform to the curved surface of a vehicle tyre 62. Such a roller shape assists in maintaining the roller 61 in contact with the vehicle tyre 62 without the need for separate guide rollers. The apparatus may be constructed with a handle which, when moved up down or sideways, automatically controls the speed or direction of the apparatus, the amount of movement and/or pressure determining acceleration rate, speed and direction. Because of the relative cheapness of the apparatus of the present invention, it is envisaged that each loading bay of an airport will have a dedicated apparatus in which case the apparatus may be connected to mains power by an appropriate cable tether. The apparatus can also be constructed relatively lightly and cheaply for light aircraft use in which case battery operation may be sufficient for normal aircraft movement. Otherwise, an appropriate hydraulic drive may be used driven by an internal combustion engine or the like.

Claims

Claims .

1. Vehicle moving apparatus for moving a vehicle which has a ground wheel, said apparatus comprising at least one rotatable ground-engaging wheel means, at least one rotatable drive roller means which is adapted to engage a peripheral surface of the vehicle ground wheel, support means for the wheel means and roller means which maintains a predetermined spacing between the respective axes of rotation, and drive means for rotating the wheel means and drive means in opposite rotational directions.

2. Apparatus according to claim 1 wherein opposed, spaced pairs of wheel means and roller means are carried by said support means to locate in front and behind the vehicle ground wheel.

3. Apparatus according to claim 1 or claim 2 wherein the wheel means comprises two or more substantially solid wheels at least one of which is driven by the drive means to move the apparatus along the ground.

4. Apparatus according to any one of claims 1 to

3 wherein said roller means comprises at least one substantially solid roller to engage the vehicle wheel peripheral surface, the surface of the roller constructed to impart a frictional driving force to the vehicle wheel when the roller is driven by the drive means.

5. Apparatus according to any one of claims 1 to

4 wherein the drive means comprises electrical or hydraulic drive motor means which rotates the wheel means and associated roller means in opposite directions at relative speeds which are a function of the respective sizes of the wheel means and roller means.

6. Apparatus according to claim 5 wherein the relative speeds may be varied to impart an acceleration or retarding force to the vehicle wheel.

7. Apparatus according to any one of the preceding claims wherein said support means carries guide rollers adapted to engage side surfaces of the vehicle wheel.

8. Apparatus according to claim 2 wherein said support means is formed with two parts pivoted together, a first part having control means connected thereto and carrying one of said spaced pairs of wheel means and roller means, a second part carrying the other of said spaced pairs, and means to pivotally move said parts.

9. Apparatus according to claim 8 wherein said support means includes means to vary the spacing between the spaced pairs.

10. Apparatus according to claim 8 or claim 9 wherein said control means includes a handle extending from said first part, the handle including speed and direction controls to actuate and vary the speed and direction of counter-rotation of the respective wheel means and roller means.

11. Apparatus according to any one of claims 8, 9 or 10 wherein said control means includes platform means for an operator.

12. Apparatus according to any one of claims 2 and 8 to 11 wherein said support means includes a pair of horizontally spaced side beams interconnected at their ends by fixed axle means, said wheel means being carried by said axle means and disposed adjacent each beam, each axle means having a part between the wheel means offset downwardly and inwardly and the roller means being mounted on the offset part of each axle means.

13. Vehicle moving apparatus for moving a vehicle which has ground wheels, said apparatus comprising support means carrying a pair of rotatable driving roller means engageable with at least one vehicle wheel and at least one ground-engaging wheel means, propulsion means to move the ground-engaging wheel means to cause one of the roller means to frictionally engage the vehicle wheel, and drive means to rotate the second roller means in a direction opposite that of the wheel means whereby the apparatus moves along the ground with the second roller means driving the vehicle wheel.

14. Apparatus according to any one of the preceding claims wherein said roller means has a peripheral shape to closely engage the vehicle wheel.

15. Apparatus according to any one of the preceding claims wherein said roller means, or the surface thereof, is constructed of one or more materials selected from the group comprising metal, hard rubber, ceramic sintered metal, abrading particles secured in a solid matrix, metal disks, impregnated composite, open ceramic, wire bristles, metal sinter and synthetic plastic material.

16. Apparatus according to any one of the preceding claims wherein hydraulic or electrically operable clamp means on the support means enables movement of one roller means relative to a second roller means to squeeze a vehicle wheel therebetween.

17. Apparatus according to any one of the preceding claims wherein said wheel means is movable relative to the support means enabling the apparatus to be steered.