NZ328793A - A roading device having a trailer unit having roading material, a grading portion and adjustment means - Google Patents

Description

328793 N.Z. PATENT OFFICE 23 SEP 1997 PATENTS FORM NO. 5 Fee No. 4: $260.00 PATENTS ACT 1953 COMPLETE SPECIFICATION RECEIVED After Provisional No: 328793 Dated: 9 August 1996 James & Wells Ref: 13761/16 GMP IMPROVED ROADING DEVICE I Ross Harold Tucker, a New Zealand Citizen of Aria Road (No Number), Aria, New Zealand hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement: 1 328793 IMPROVED ROADING DEVICE technical field I This invention relates to a device used in the construction of roads, paths or tracks.

Background Art Roads are constructed to provide a surface which most vehicles may easily traverse. One idrf the most simple types of road in use consists of a c- ■ flat surface upon which roading material such as shingle, sand, or small stones are laid.

Such a road provides a surface upon which vehicles may have greater traction than mud or damp earth, and allow easy drainage of the road surface.

To create such a road, roading material is firstly dumped by a dumping trailer along the proposed road svirface. The dumped material is then graded in a second procedure by a grader, to ensure the roading material is distributed evenly along the road surface, and that the road surface is substantially flat.

In most cases such road construction work must be done during the summer months of the year to ensure good weather conditions and a dry surface upon which the roading material is to be laid. Laying and grading roading material in wet conditions, or when the proposed road surface is muddy, is dangerous for the operators of both the dumping trailer and grading machine. 2 328793 Firstly standard dumping trucks used to lay roading material do not have the required traction with which to propel the machine over muddy surfaces. A dumping trailer used in such conditions will ruin a previously flat earth path by digging deep ruts into the earth with its wheels. The same is true of a grading machine used in such conditions, as the wheels used by such machines are not of the required size or contain large enough tread to deal with the muddy conditions.

The grading machines currently in use include a large blade mounted at the front of the machine which pushes excess roading material ahead of the machine. The blade used to grade the roading material is usually a long curved portion, and as excess roading material builds up in front of the grader, the roading material may spill around the sides of the blade.. This results in material wasted on what will be the side of the road.

The dumping trailer and towing vehicle travel at a slow rate due to the uneven dirt surface they must traverse. This limits the speed of the road construction operation and prevents the machinery used from travelling at sufficient speed and obtaining enough momentum to cope with muddy ground conditions and steep hill gradients.

With existing dumping trailers there is limited control over where roading material is dumped. The trailer has its rear side removed and the top end of the trailer bed elevated to slide the roading material out from the trailer bed. The roading material is sprayed from the back of the trailer at a rate determined by the elevation of the other end of the trailer bed. 3 328793 This method of distributing roading material allows very little control over where the roading material is dumped. The roading material sprays from the back of the trailer and may land to either side of the proposed road surface.

Existing roading trailers are required to support their own weight when not attached to a towing vehicle, usually by the inclusion of two axles, with an axle at either end of the roading trailer. Without two axles the trailer would transmit a large amount of force to the connection point with the towing vehicle, and most certainly break any conventional connection means.

In addition, to distribute and grade roading material three workers are normally required. In most instances the first worker operates a front end loader which is used to fill a dumping trailer. Two more staff are also required to drive the dumping trailer and to drive a grading machine. The need for three separate workers and the associated machinery they operate greatly increases the running costs of any business which lays and grades roading material.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. 4 328793 disclosure of invention According to one aspect of the present invention there is provided a roading device including a trailer unit, grading portion and. adjustment means, wherein the grading portion is attached indirectly or directly to the trailer unit, the roading device characterised in that adjustment means may cause the grading portion to move relative to the surface being graded.

According to further aspect of the present invention there is provided a roading device including a trailer unit, grading portion and height adjustment means, wherein the grading portion is attached indirectly or directly to the trailer unit, the roading device characterised in that the height adjustment means may move the trailer unit causing the grading portion to move relative to the surface being graded.

According to another aspect of the present invention there is provided a roading device including a trailer unit, grading portion and angle adjustment means, wherein the grading portion is attached indirectly or directly to the trailer unit, the roading device characterised in that the angle adjustment means may move the trailer unit causing the grading portion to move relative to the surface being graded.

The term trailer unit referred to throughout shall include any combination of or all of the components of a trailer device. These components may for example be a trailer bed, ia trailer draw bar, a trailer wheels, axes, or chassis. 328 The trailer unit in a preferred embodiment contains roading material and allows this material to exit or be discharged from the trailer units bed.

In a preferred embodiment of the present invention the towing vehicle is a tractor. A tractor may tow a trailer unit over rugged hilly terrain and wet muddy conditions with use of large deep treaded tyres and a powerful engine.

A tractor is the preferred vehicle used to tow a trailer unit, as it is specifically adapted to cope with rough conditions and is lightweight in construction compared with other existing vehicles. A tractor is specifically designed to tow loads in rough conditions and does not include the extra weight associated with allowing other activities to be performed. For example, a tractor and it's engine does not need to be adapted to tow a load at high speed along a sealed highway - unlike conventional earth working machines.

In a preferred embodiment the trailer unit is elevated above ground at pne end by an attachment to the tractor, and supported at the other end by a series of wheels located at the rear of the trailer units. This arrangement distributes the weight of the trailer unit onto the rear wheels of the tractor and trailer unit. With a large load pressing onto the tractor's rear end, the rear wheels of the tractor are provided with strong traction with the ground.

Other embodiments of the present invention may not use a tractor as the towing vehicle. For example other embodiments may use four wheel drive vehicles such as trucks or track vehicles which allow movement through rough and muddy terrain. 0 328793 Reference throughout this specification shall now be made to the towing vehicle as being a tractor. However it should be appreciated that in other embodiments of the present invention different towing vehicles may be used.

In a preferred embodiment the trailer unit includes an adjustment means. Such an adjustment means may be configured to allow the grading portion to be moved into a desired position or angle by the operator. In a further preferred embodiment the adjustment means includes a height adjustment means which may vary the height of the grading portion above the surface to be graded, and an angle adjustment means which may vary the angle that the grading portion makes with respect to the surface to be graded.

In a further preferred embodiment the angle adjustment means may move the grading portion so that it swivels left or right with respect to the surface to be graded, or swivels up and down with respect to the surface to be graded.

In a preferred embodiment the height adjustment means consists of two hydraulic rams mounted underneath either rear end of the trailer bed of the trailer unit. These hydraulic rams may be activated by the roading device operator to raise or lower either corner of the trailer bed to acfjust the height of the trailer bed and attached grading portion above the surface to be graded.

The use of two hydraulic rams as the height adjustment meara allows the grading portion to be tilted with respect to the surface being graded.

This allows the grading portion to be much lower at one end than the other selectively grading sections of the surface to be graded. 7 This feature provides the roading device user an advantage when roading material is to be shaped into an angled corner, which requires a large amount of roading material to be distributed on the outside of the corner and a small amount on the inside. The grading portion may be tilted to bite deeply into the roading material at one end and not at all at the other to form a cambered surface.

In other embodiments of the present invention two hydraulic rams may not be used as the height means. Any device which may raise the end of a trailer bed relative to the other end of the bed may be used as the height adjustment means. For example some embodiments may use a winch and lifting chains, mechanical ratchet arrangements, air or gas driven rams, or threaded drive shafts which may be screwed up and down as the height adjustment means.

Other embodiments may use height adjustment means which do not adjust the height of one corner of the trailer bed relative to the other closest corner of the trailer bed. Such a height adjustment means may simply raise and lower on end of the trailer bed, not being able to tilt any grading portion attached to the trailer bed.

T v a preferred embodiment of the present invention the angle adjustment means consists of two hydraulic rams positioned on either side of the trailer bin. These rams are configured so that they may act to twist the sides of the trailer bin left or right and thereby angling any grader portion attached to the trailer bin left or right.

As with the height adjustment means discussed previously other embodiments may use other types of angle adjustment means, not necessarily hydraulic rams. For example, other embodiments may 8 employ winches and transmission chains, or a threaded shaft drive which may be wound in and out of the angle adjustment means.

Angling of the grading portion left or right allows the grading portion to cut through dense material with the same action as a knife point. The forward edge of the grader portion acts to start a cut in the graded surface, with more of the grader portions edge being applied to any resistant material on the graded surface as the trailer is towed over the surface.

According to one aspect of the present invention there is provided a method of attaching a trailer to a towing vehicle, wherein the trailer includes a draw bar, and the towing vehicle includes receiving means to which the trailer draw bar can be attached, the method of attaching characterised by the steps of; a) attaching a support harness to the towing vehicle in such a manner so that the support harness can at least partially support the weight of the trailer via the trailer draw bar, and b) attaching the trailer draw bar to the receiving means of the towing vehicle.

In a preferred embodiment of the present invention the draw bar used to distribute the trailer's weight on to the tractor shall consist of a long solid steel section containing one or more apertures along its length. In some instances these apertures may be used to attach the draw bar to the tractor towing the trailer.

The method of attaching a trailer to a towing vehicle will now be described with reference to the towing vehicle being a tractor and the 9 trailer being a dumping trailer which allows the dumping of material as the trailer is towed. It should be understood however that the means described to attach the towing vehicle and trailer should not necessarily be limited to use with tractors and dumping trailers. This apparatus has a wide variety of applications where any type of load is drawn or towed by a vehicle.

In a preferred embodiment of the present invention the draw bar used to distribute a trailer's weight onto the tractor may be of a variable length depending on the use to which the roading device is to be put. It is envisaged the draw bar may be of an extended length with only the required length of draw bar protruding from the end of the trailer unit. If a longer draw bar is required (for example when the roading device is turning a sharp corner) the extra length of draw bar may be drawn out from inside the trailer unit. If a shorter draw bar is required then the excess length of draw bar may be inserted back into the trailer unit.

In a preferred embodiment of the present invention the support harness used to partially support the weight of the trailer through the trailer draw bar shall consist of a sling through which the draw bar may be inserted. The sling may be configured with a lower base wide enough to support the draw bar closely on the bottom and both opposite sides when the sling is pulled up around the draw bar.

The top of the sling may taper to a point attaching both sides of the sling together at which point the sling may be attached to the tractor. The bottom of the sling may be attached to the draw bar with use of the apertures located along the draw bar's length. A corresponding aperture may be provided in the base of the sling through which a connector such as a bolt may be inserted through the sling and draw bar to be secured on either ends with nuts.

The top tapering end of the sling may be attached to the tractor at a point higher on the tractor than the attachment point of the draw bar to the tractor.

The combination of support harness and draw bar attachment allows each attachment portion to partially support the trailer through the trailer draw bar. Partially supporting the draw bar with two separate attachments transmits less stress to the attachments than with using just one attachment point. This attachment means allows the support of a draw bar transmitting forces which would break standard configurations of draw bar attachments to trailers.

The receiving means of the tractor used to attach the draw bar to the tractor shall in a preferred embodiment be a draw bar attached to the tractor which includes one or more apertures along the tractor draw bar's length. A pin may be inserted through corresponding apertures in the trailer draw bar with the pin being able to extend into an aperture in the tractor draw bar. The pin may then be secured, effecting the attachment of the trailer draw bar to the tractor draw bar.

In a preferred embodiment the receiving means is configured so that the tractor draw bar lies below the trailer draw bar when the two draw bars are connected together with use of a pin. In a further embodiment the support harness may be attached to either draw bar at the same point where both draw bars are attached together.

It should be appreciated by those skilled in the art that the method of attaching the draw bars and support harness together described is only one embodiment only and many other methods of attachment may be used.

The roading device may consist of a towing vehicle attached to a trailer unit. In a preferred embodiment of the present invention the towing vehicle is a tractor.

The grading portion attached to the trailer unit may consist of any length of material which extends partially or wholly across the width of the svirface to be graded.

In another embodiment of the present invention there may be provided a means to lock the trailer wheels at a set angle with respect to those of the tractor. Locking the trailer's wheels at a set angle has the same effect as angling the entire trailer bin, due to the trailer being towed at an angle offset by the angle the trailer wheels are locked at.

According to another aspect of the present invention there is provided a trailer unit capable of holding roading material including doors which allow the exit of roading material from the trailer unit, the trailer unit characterised in that the doors are configured so that a svirface or surfaces of the doors can be used to grade roading material that has exited from the trailer unit. i In a preferred embodiment of the present invention the trailer unit shall include doors to allow the exit of roading material carried by the trailer unit. Such doors may be defined as 'dump doors'. The dump doors may have their height above the surface to be graded adjusted so the dump doors may contact the roading material distributed along the surface. 12 By allowing the dump doors to have their height above the surface to be graded adjusted by an operator the dump doors may be used to grade sections of the surface traversed. An operator may adjust the height of the doors above ground, which will determine the level to which the svirface is to be graded. In this manner there is no need to include a separate grading blade on the trailer unit, as the doors may be used for this function as well as allowing the exit of roading material frpm the device.

In another embodiment of the present invention a separate grader blade may be attached to the trailer unit and used as the grading portion. This grader blade may be attached to the underside of the trailer with the height-of the grader blade above the surface to be graded adjusted by the height adjustment means.

In this way a grader blade attached to the underside of the trailer unit may be used to selectively grade portions of the grading surface by the tilting of the trailer bed (and hence grader blade) by the height adjustment means. Preferably, a blade used in this application may be a curved grader blade normally used on grading machines which do not discharge roading material.

In one embodiment of the present invention two or more doors may be included in the trailer unit to allow the exit of roading material from the trailer from two or more different points. In this manner the roading device operator has greater control over the distribution of material dumped by the trailer unit. An operator may selectively control how much roading material is distributed on several sections of the proposed road surface. In this way the position of material discharged from the trailer unit may be controlled.

In a preferred embodiment dump doors are configured to allow their use as a grading portion to grade roading material distributed along a surface to be graded.

In another embodiment of the present invention where doors are included in the trailer unit used to dump roading material may be controlled by an operator to allow the variable flow of roading material dumped on the proposed road surface. The operator may adjust the size of the aperture created by an open door by controlling the angle made with the trailer unit by the dov/r.

Another embodiment of the present invention the same controls used to adjust the orientation of trailer unit doors may also bt used to adjust the height of the doors above the surface to be graded when the doors are used as a trailer grading portion. These same controls may be used when all the roading material has been dumped, opening the trailer unit doors to brining a surface of the door down into contact with the surface to be graded.

The means used to control the orientation of trailer unit doors is in a preferred embodiment one or more hydraulic-rams. However any device which may raise or move the trailer unit doors with respect to the trailer unit bed. For example, some embodiments may use a winch and metal rope arrangement, a mechanical ratchet arrangement, air or gas driven rams, or threaded shafts which may be screwed up and down by a drive shaft. 14 328793 According to another aspect of the present invention there is provided a trailer unit which contains and discharges roading material, the treuler unit including wheels which support the trailer unit, whereby the wheels are distributed positioned substantially linearly to each other across the width of the roading discharged, characterised in that the wheels act to roll out roading material discharged from the trailer unit.

In a preferred embodiment of the present invention the wheels used to support the trailer unit are distributed substantially linearly with respect to one another across the width of the rear of the trailer unit.

As the wheels are distributed substantially linearly with respect to one another across the width of the rear of the trailer unit, the wheels evenly roll the roading material underneath the wheels. This configuration of wheels prevents ruts forming in the proposed road surface as the weight of the trailer transmitted through the wheels is transmitted along several points substantially in a line, instead of two points which normally would form two deep ruts.

In a preferred embodiment the wheels distributed across the width of the * trailer unit are configured so that the outside wheels are positioned ahead of wheels nearer the centre of the trailer unit. This configuration of wheels allows the use of the suspension system described in further detail below.

A set of wheels refers to one or more wheels linked together so the set acts substantially as a single wheel. 323793 According to another aspect of the present invention there is provided a vehicle suspension system for use with at least four sets of wheels, wherein at least two sets of wheels are positioned on the opposite side of the vehicle to two or more other sets of wheels, with sets of wheels on the same side of the vehicle configured so that one set is positioned ahead of the oilier set or sets of wheels, the suspension system characterised in that the system allows wheels on one side of the vehicle to be raised when wheels on the opposite side of the vehicle are lowered, and wheels one side of the vehicle to be raised when wheels in front or behind on the same side of the vehicle are lowered.

The suspension system which allows complimentary movement of wheel sets may in a preferred embodiment include a modified walking beam suspension system.

In one embodiment the wheels may be configured as described above substantially in a line across the rear of a trailer unit with the front wheel sets positioned ahead of the centre wheel sets. This configuration allows a modified walking beam to be used. The walking beam may pivot the centre wheels downwards when the outside wheels are raised, or the centre wheels upwards when the outside wheels are lowered. This allows the rear of the trailer unit to remain substantially level when the unevenness of the ground means that some wheels encounter ruts or mounds when other wheels do not.

In a preferred embodiment a lateral pivot may also be included in the suspension system. The lateral pivot allows pivoting of wheels on either 16 328793 side of the trailer unit, so when wheels on one side of the trailer unit are raised wheels on the opposite side of the trailer unit are lowered.

In a preferred embodiment the suspension system used shall include both the modified walking beam configuration of suspension system and the lateral pivot suspension system, to allow the trailer unit wheels to traverse rough ground at higher speeds than normally achievable. lu an alternative embodiment the suspension system may include a lateral pivot suspension system which allows pivoting of wheel sets relative to an adjacent wheel set. For example, where four wheel sets are involved as configured in the preferred embodiment of the invention, these wheel sets may pivot along three separate lateral pivot axis. A wheel set may pivot up or down relative to an adjacent wheel set using such lateral pivots.

This configuration of lateral pivots suspension system allows a vehicle's wheels to traverse extremely rough ground without having to reduce the vehicle's speed.

In a preferred embodiment of the present invention the trailer unit bed is configured in a triangular or an inverted A-frame shape. The bed is orientated so one side of the triangle forms a line across the width of the surface traversed, allowing the apex of the frame to be used as the grading portion. The bed may also include one or more discharge apertures, which allow material to be discharged from the trailer bed onto the surface to be graded.

In a further preferred embodiment, dump doors may be used in conjunction with a trailer bed's discharge Aperture. Dump doors may be 17 328793 situated on the front side of the bin lowest to the ground to allow material to be dumped in a line across the surface traversed.

Any configuration of dump doors may be used in the preferred embodiment, for example these doors being configured to open outwards from the body of the bin or to slide up the bin surface.

In a preferred embodiment a height adjustment means is attached to the A-frame bin to allow the adjustment of bin height with respect to the surface traversed. With this attachment, the lower edge of the bin may be used to grade the surface traversed. In addition, if the bin doors are opened, excess roading material after grading may be collected in the bin and reused on a later run. This is in direct contrast to existing grading devices which may only propel a set amount of material in front of the grading blade before material begins to spill around the sides of the blade.

In a preferred embodiment the trailer bin may be configured as an inverted triangle with control blocks inserted in the inside of the bin near the lower edge of the bin closest to the ground. Control blocks may be placed inside the trailer beds discharge aperture to prevent the discharge of material onto certain positions of the surface to be graded.

Wing attachments may also be included on the sides of the bin closest to the ground to control the spread of roading material dumped by the trailer.

The use of blocks located inside the trailer bed near the trailer's discharge aperture and wings attached to the sides of the trailer bin provides the roading devices operator some control with regard to where roading material is dumped. Roading material is prevented from 328793 spreading past the wing attachments and is not dumped from any portion of the trailer bin which is covered by an internal control block.

The height adjustment means which adjusts the trailer bins height with respect to the ground may also be used to regulate the amount of material dumped by the trailer bin. Material may be dumped on the surface traversed to a height equal to that of the lower edge of the trailer bin. Material cannot be dumped to a height greater than the lower edge of the trailer bin as the trailer bin will act to grade and collect excess material at the height of its lower edge.

The major advantage the present invention has over prior art devices is the great reduction in the capital costs required to set up a roading construction business. Instead of using a dumping trailer and a. grading machine such a businesses operator need now only buy one piece of equipment constructed in accordance with the present invention.

In addition, labour costs for such a businesses operator are also reduced. One workman only n^ay be required to complete a particular job. This workman may drive a loading machine, such as a front end loader into the trailer unit, and travel to the jump site. The workman may then use the loading device to fill the trailer unit, and subsequently discharge roading material onto a surface and grade same using the present invention. 19 323793 brief description of drawings Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: Figure la and lb a view of the support harness and attachment means used to attach the trailer draw bar to the towing vehicle; Figure 2 a perspective view of the height adjustment means used to angle a grader blade attached to the bottom of the trailer unit, and Figure 3 a perspective view of the trailer unit including dump doors controlled to be used as a grading surface, and Figure 4 is a diagram showing the configuration of wheels distributed along the rear of the trailer unit including the pivot axis used by the suspension system. best modes for carrying out the i Figures la and lb illustrate a frontal view of the attachment means 1 used to attach the trailer draw bar 2 to the tractor draw bar 3.

The trailer draw bar 2 includes an aperture 4 through which pin 5 is inserted. Pin 5 is also inserted through apertures 6 in the tractor draw bar 3.

Supporting the tractor draw bar 3 and trailer draw bar 2 is sling 7 attached to the tractor via the top link hole 8.

Figure 2 illustrates one embodiment of the dumping trailer 10.

Trailer 10 is supported at one end via wheels 11 distributed along the width of the surface roading material 12 is dumped upon.

Roading material 12 exits the trailer 10 via aperture 13 caused by the pivoting of dump doors 14.

Trailer bed 15 may be tilted with use of the trailer height adjustment means in this embodiment hydraulic rams 16a and 16b.

Rams 16 may tilt the trailer bed 15, adjusting the angle at which the trailer bed edge 17 makes with the surface traversed.

Figure 3 shows another embodiment of the dumping trailer 20.

Again the trailer wheels 21 are distributed along the width of the surface to be traversed.

In this embodiment of the invention roading material has been dumped from the trailer bed 22 with the dump doors 23 being wide open.

The dump doors 23 may now been used to grade the proposed road surface as the trailer 20 is towed via draw bar 24 and the towing tractor (not shown).

Hydraulic rams 25a and 25b are used to control the orientation of dump doors 23 with respect to the trailer bed 22.

By changing the orientation of dump doors 23 the proposed road surface may be graded to a specific height. This height may be controlled with use of the hydraulic rams 25.

Figure 4 illustrates the configuration of the trailer's rear wheels in one embodiment. 21 328793 Four sets of trailer wheels 30 are shown with the inside sets of wheels leading the outside sets.

Dotted lines 31 and 32 illustrate the pivot axis upon which the vehicle suspension system may pivot to allow the trailer to be used on uneven ground.

When the left hand wheel sets are raised by the road surface pivot axis 31 allows the right hand wheel sets to pivot downwards.

When the inside wheel sets are raised by the road surface pivot axis 32 allows the outside wheel sets to be pivoted downwards with respect to the raised inside wheel sets.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof. 22

Claims (23)

WHAT I CLAIM IS: 3 2 0 7 9 3 .
1. A roading device including a trailer unit, grading portion and adjustment means, wherein the grading portion is attached indirectly or directly to the trailer unit, wherein the trailer unit is configured to contain roading material, the roading device characterised in that adjustment means is configured to cause the grading portion to move relative to the surface being graded.
2. A roading device as claimed in claim 1 wherein the adjustment means causes the grading portion to move by moving the trailer unit.
3. A roading device as claimed in claim 1 or claim 2 wherein the adjustment means includes a height adjustment means.
4. A roading device as claimed in any one of claims 1 to 3 wherein the adjustment means includes an angle adjustment means.
5. A roading device as claimed in any previous claim wherein the height adjustment means may raise or lower one end of the trailer unit with respect to the surface to be graded.
6. A roading device as claimed in claim 5 wherein the height adjustment means may raise a corner of one end of the tailer unit while leaving the other corner at that end substantially in the same place.
7. A roading device as claimed in any previous claim wherein the height adjustment means includes a hydraulic ram. 23 328793
8. 8. A roading device as claimed in any one of claims 1 to 6 wherein the height adjustment means includes a winch linked to one or more lifting chains.
9. 9. A roading device as claimed in any one of claims 1 to 6 wherein the height adjustment means includes a threaded drive shaft which may be wound up or down.
10. 10. A roading device as claimed in any previous claim wherein the angle adjustment means includes a hydraulic ram.
11. 11. A roading device as claimed in any one of claims 1 to 9 wherein the angle adjustment means includes a winch and transmission chains.
12. 12. A roading device as claimed in any one of claims 1 to 9 wherein the height adjustment means includes a threaded drive shaft.
13. 13. A roading device as claimed in any previous claim wherein the roading device includes the grading portion extending substantially across the width of the trailer unit and the surface to be graded.
14. 14. A roading device as claimed in any previous claim wherein the grading portion includes a blade attached to the bottom of the trailer unit.
15. 15. A roading device as claimed in claim 14 wherein the blade attached to the bottom of the tailer unit is a curved grading blade.
16. 16. A roading device as claimed in any one of claims 1 to 13 wherein the grading portion is the bottom of the bed of the trailer unit. f. £NT QFRCF' 24 2 0 NOV 1997 93
17. 17. A roading device as claimed in claim 16 wherein the bed of the trailer unit is configured substantially in the shape of an inverted A frame, and the apex of the A frame is used as the grading portion.
18. 18. A roading device as claimed in claim 17 wherein the inverted A frame trailer unit bed includes at least one discharge aperture.
19. 19. A roading device as claimed in claim 18 wherein the trailer unit includes one or more control blocks positioned in a discharge aperture.
20. 20. A roading device as claimed in claim 18 or 19 wherein the trailer unit bed includes one or more guiding wings on either side of the discharge aperture.
21. 21. A roading device as claimed in any previous claim wherein the trailer unit includes one or more doors which allow material to be discharged from the trailer unit.
22. 22. A roading device as claimed in any previous claim which includes a trailer unit capable of holding roading material and including doors which allow the exit of roading material from the trailer unit, the trailer unit characterised in that the doors are configured so that the surface or surfaces of the doors can be used to grade roading material that has bee^ discharged from the trailer unit.
23. 23. A roading device as claimed in either one of claims 21 or 22 wherein the roading device includes a plurality of doors located along the width of the trailer unit which control the position of material discharged from the trailer unit. f-^Hl^ioFRcr 25 j ^ 0 NOy t997 ui A A roading device as claimed in any previous claim wherein Hie trailer unit may be towed by a four wheel drive vehicle. A roading device as claimed in any one of claims 1 to 23 wherein the trailer unit may be towed by a tractor. A roading device as claimed in any previous claim wherein the trailer unit includes wheels which support the trailer unit, whereby the wheels are distributed and positioned substantially linearly to each other across the width of the roading material dumped, characterised in that the wheels act to roll out roading material that has discharged from the trailer unit. A roading device as claimed in claim 26 wherein the trailer unit includes a suspension system. A roading device as claimed in claim 27 wherein the suspension system includes a lateral pivot suspension system. A roading device as claimed in any previous claim wherein the roading device includes a vehicle suspension system for use with at least four sets of wheels, wherein at least two sets of wheels are positioned on the opposite sides of the vehicle to two or more other sets of wheels, with sets of wheels on the same side of the vehicle configured so that one set is positioned ahead of the other set or sets of wheels, the suspension system characterised in that the system allows wheels on one side of the vehicle to be raised when wheels on the opposite side of the vehicle are lowered, and 26 j 2 0 NOV 1397 j 3 2 8 7 9 wheels on one side of the vehicle to be raised when wheels in front or behind on the same side of the vehicle are lowered. A method of attaching a towing vehicle to a roading device as claimed in any previous claim, wherein the roading device includes a trailer unit which includes a draw bar, and the towing vehicle includes receiving means to which the trailer draw bar can be attached, the method of attaching characterised by the steps of; a) attaching a support harness to the towing vehicle in such a manner so that the support harness can at least partially support the weight of the trailer via the trailer draw bar, and b) attaching the trailer draw bar to the receiving means of the towing vehicle. A method of adjusting the position of a grading portion attached indirectly or directly to a trailer unit which contains and allows the exit of roading material, characterised by the steps of: a) activating an adjustment means, and b) the adjustment means altering the height of the grading portion or angle of the grading portion with respect to the surface to be graded. A roading device substantially as herein described with reference to the accompanying examples and/or drawings. *' OFFICE 27 2 0 NOV 1997 32 87 9 3 A method of rolling out roading material substantially as herein described with reference to and as illustrated by the accompanying examples and/or drawings. ROSS HAROLD TUCKER by his Attorneys END OF CLAIMS ' uvii office 28 2 0 HOV 1997