The present invention relates to support platforms and belt assemblies, particularly those having wide belts. One particular application is a belt assembly for use as a self-propelled support platform solely supported on top of bushes of plants, such as tea plants. The support platform may carry equipment or machines used in the cultivation and harvesting of the plants, but the invention has general application in a wide variety of equipment which uses a wide belt for carrying, supporting or conveying materials.

As used herein, the term 'wide belt' refers to a belt where the width ( transverse dimension) relative to the length (longitudinal dimension, ie the direction in which the belt moves when driven by at least one pulley, roller or the like) causes difficulty with tracking when using existing conventional tracking means.

BACKGROUND TO THE INVENTION

Prior art disclosed in International Publication Number WO 93/02544 discloses means of supporting a tea harvester on a tea bush canopy composed of a support area with the harvesting attachment pivoted and a forward roller supporting the tea harvesting mechanism. Difficulty is encountered because of the weight relevant to the support platform and in particular the harvesting means being supported by a roller with minimum tea canopy contact.

It is desirable to provide a durable, light weight support means on a tea canopy for carrying cultivating and/or harvesting equipment, such as pruners, skiffers, sprayers, fertilisers and levelling machines to grade and level the tea canopy providing an exact height control relative to the tea canopy for selective tea harvesting.

SUMMARY OF THE INVENTION

According to a broad aspect of the invention, there is provided apparatus for use in the cultivation and/or harvesting of plants, such as tea, including a support platform which, in use, is adapted to extend above a canopy of bushes for supporting cultivation and/or harvesting equipment and/or harvested plant material plucked from the bushes, the support platform including a support frame and at least one belt adapted to contact the canopy of bushes and being movable over the bushes.

The support platform, provides a stable platform for absolute plucking control relative to the surface last harvested regardless of the terrain and the contour of the ground.

In one preferred embodiment, the support platform includes guide means adapted to be positioned in at least one track between adjacent rows of bushes.

The at least one belt preferably includes rollers for tracking and/or for tensioning the belt. In one preferred embodiment, the at least one belt is a continuous belt which extends around a pair of rollers provided at front and rear ends of the belt. Such a continuous belt may be self-propelled, with the front roller acting as a drive roller, and the rear roller acting as a driven roller.

The support platform may include a plurality of belts. The belt or belts are preferably of sufficient area and positioned to provide a stable centre of gravity with allowance for the variable weight of tea cultivation or harvesting equipment and/or harvested crop.

The self propelled platform ensures that the plucking table maintains a level surface and absolute height control for the selection and harvesting of the finest quality tea leaf on a constant and consistent basis.

In a particularly preferred embodiment, the support frame is constructed from lightweight tubes and fittings with cross-bracing.

In a particularly preferred embodiment, the at least one belt has a tracking strip. Preferably the tracking strop is reinforced, for example by one or more fibres, wires or cords. Such a tracking strip assists in providing better tracking for the belt so that it requires minimal maintenance adjustment with reduction of most belt stress apart from that necessary to drive the belt.

Self tracking using a crowned pulley or roller is well known and effective in narrow width long belts. However, with wide short belts, a crowned pulley or roller cannot cause the belt body to move sideways and the crowned pulley becomes ineffective.

In certain applications it is necessary to use a lightweight small diameter drive pulley or roller. Attempts to track a wide short belt with a crowned small diameter roller will only cause the roller to deflect with the greatest degree of deflection at the centre, thus negating the crown effect and destabilising the belt tracking.

A wide belt running with 180 degree contact across the full width of the driven roller then provides a very significant contact area between the belt and roller. Even with the best manufacturing techniques the length of one side of the belt relevant to the other can vary, in some cases by as much as 0.5 mm.

With continuous rotation of the roller or pulley this small difference in belt length is compounded. For example, 0.5mm x 500 rotations equals a variation of 250mm of additional travel of one side of the belt relative to the other resulting in diagonal opposing forces with the result that the belt tracks offline even with a belt that is correctly adjusted.

Another attempt to track wide belts has been by using edge guide strips. One can see logically that with the friction of a wide belt wrapped 180 degrees around and across corresponding wide rollers of a driven and a free roller a substantially large force will be required to move the belt across the rollers which can affect the integrity of the edge of a thin belt. The force required to align the belt on the rollers by pushing on the edge of the thin belt is likely to buckle the edge of the belt before overcoming the friction of the belt on the rollers. This means the tracking edge guide strips have marginal, if any, benefit of providing and maintaining tracking on a wide short belt.

Another way of tracking that has been previously proposed is to fit a V-type tracking protrusion bonded on the inner side at an outer edge of the belt. For wide short belts the difficulty of tracking as described above overrides the tracking forces provided by V-type tracking protrusion and readily stretches the edge of the belt to a point that the tracking strip is ineffective. External forces acting on the belt can causes the belt to suddenly override the tracking strip and double back to run over the top of the belt turning it inside out on the edges.

All of the forces described above acting over time on a wide belt, and further variation in the lengths of the opposite sides of the belt caused by improper adjustment, can cause the belt to be severely impaired showing crease lines across the surface of the belt. Tracking can then only be provided by reasonably frequently adjusting the tension and position of each side and each end of both the driven and free running rollers. In a preferred embodiment, the apparatus includes a tracking strip on at least one side edge of the at least one belt the tracking strip being engageable with a guide portion of a roller end member of at least one of the pair of spaced apart rollers at the front and rear ends of the belt. Preferably, the tracking strip is adapted to engage with a drive roller of the pair of rollers, and is reinforced so as to be substantially inextensible when the belt is driven by the drive roller.

According to a second aspect of the invention, there is provided a belt assembly for carrying, supporting or conveying tools or other articles or materials including a belt which extends around a pair of spaced apart rollers having roller end members, the belt having a tracking strip on at least one side edge, the tracking strip including a tracking portion engageable with a guide portion of a roller end member, wherein the tracking strip is adapted to engage with a drive roller of the pair of rollers and is reinforced so as to be substantially inextensible when the belt is driven by the drive roller.

Such an arrangement provides tracking that is unlikely to stretch or misalign and will continue tracking over a long period of time without much adjustment.

Preferably, the roller end member of the drive roller has flat surfaces in frictional contact with at least one surface of the tracking strip adjacent the tracking portion. This helps to reduce opposing forces on the main body of the belt. Any variation of the belt length on the opposite sides of the belt caused at the time of manufacture or by subsequent inaccurate belt tensioning is accommodated and equalised by minor slippage on the relatively narrow flat drive areas.

The other roller of said pair of rollers is preferably an idler roller. The tracking strip is preferably engageable with roller end members of the idler roller via a bearing assembly. Internal bearings of the bearing assembly allow belt forces to equalise so that opposing loads in the belt are reduced.

In a particularly preferred embodiment, a reinforced tracking strip is provided at each side edge of the belt and engages with the roller end members in such a manner that a central body part of the belt between the reinforced tracking strips is separated from the rollers by a clearance gap. This helps to keep the main body of the belt free from any frictional forces on the parts of the drive and/or idler rollers between the roller end members.

In one preferred embodiment, the tracking portion of the or each tracking strip includes a tracking protrusion adapted to be received in a complementary guide groove or recess in a respective roller end member. The complementary protrusion and recess are preferably trapezoidal shaped, but may take other forms, for instance they may be V-shaped, U-shaped, or square shaped.

The guide grooves or recesses in the roller end members provide guidance for the tracking strip which cannot move out of the guide grooves or recesses because of the substantially inextensible nature of the tracking strip.

The belt assembly may also include adjustment means for adjusting the tension of the belt. In one embodiment, the adjustment means preferably includes a bearing assembly, a spacer and an adjustment control member. The adjustment means is preferably provided at the idler roller.

According to a third aspect of the invention, there is provided a belt for use in the apparatus of the first aspect or the belt assembly of the second aspect wherein the belt has a substantially inextensible reinforced tracking strip on at least one side edge, the tracking strip including a tracking portion. Preferably, both edges of the belt are provided with a reinforced tracking strip.

The at least one tracking strip of the belt is preferably reinforced with at least one fibre, wire or cord. More preferably, the tracking strip is reinforced with a plurality of reinforcing fibres, wires or cords, and not just a single fibre, wire or cord in the region of the tracking protrusion. The plurality of reinforcing fibres, wires or cords extend across the flat drive area of the tracking strip immediately adjacent to the tracking protrusion so that the tracking strip is substantially inextensible. The reinforcing fibres, wires and cords provide substantially uniform length and tension across the flat area of the tracking strip to provide substantially uniform drive means.

Preferably, the or each fibre, wire or cord is made from one or more of the following: Kevlar, carbon fibre, steel or other high tensile fibre. The or each fibre or cord may be a multi-strand fibre, wire or cord. The or each reinforcing fibre or cord restrains the belt from stretching even under high loads. The at least one tracking strip preferably extends along the entire side edge of the belt.

In one preferred embodiment, the belt is made of homogeneous urethane or like material. The at least one tracking strip may be formed integrally with the belt. Alternatively, the at least one tracking strip may be bonded to a side edge of the belt.

According to another aspect of the invention, there is provided a drive roller for use in apparatus according to the first aspect, or a belt assembly according to the second aspect, wherein at least one drive roller includes roller end members at each end of a central roller portion, each roller end member having a diameter greater than the central roller portion, flat surfaces for engagement with a tracking strip at a side edge of a belt, and a guide portion for engagement with a tracking portion of the tracking strip.

According to a further aspect of the invention, there is provided an idler roller for use in the belt assembly of the first aspect, wherein the idler roller includes roller end members at each end of a central roller portion, each roller end member having a diameter greater than the central roller portion, and a guide portion for engagement with a tracking portion of a tracking strip at the side edge of a belt.

The idler roller preferably includes a free running roller assembly for engagement with the tracking strip of a belt, and a bearing assembly for isolating the area of engagement from the roller end portion.

The idler roller may further include adjustment means for adjusting the tension of a belt, the adjustment means including a bearing assembly, a spacer and an adjustment control member.

The roller end members of the drive roller and/or the idler roller may made of one or more of the following materials: Kevlar, carbon fibre, high tensile steel or aluminium or other high tensile metal or fibre.

The central roller portion of the drive roller and/or the idler roller is preferably a tubular member, and may be made of one or more of the following materials: Kevlar, carbon fibre, high tensile steel or aluminium or other high tensile metal or fibre. According to another aspect of the invention, there is provided a method of forming a wide belt including the steps of: forming a wide belt of urethane or other flexible material; forming at least one reinforced tracking strip; the at least one reinforced tracking strip being applied to a side edge of the wide belt,

wherein the at least one reinforced tracking strip is substantially inextensible and is adapted to engage with a roller end portion without stretching, the tracking strip having a tracking portion for engagement with a guide portion of a roller end portion.

The tracking strip is preferably reinforced with at least one, and preferably a plurality of reinforcing fibres, wires or cords. The or each fibre, wire or cord may be formed from one or more of the following materials: Kevlar, carbon fibre, steel or other high tensile fibre. The or each fibre, wire or cord may be a multi-strand fibre, wire or cord.

The method may include the step of extruding material around the or each reinforcing fibre, wire or cord to form the tracking strip. The extruded material may be homogeneous urethane or like material.

In one preferred method, the at least one reinforced tracking strip may be formed integrally with the belt. The belt may be extruded from the same material as the material around the or each reinforcing fibre, wire or cord of the tracking strip.

Alternatively, the at least one reinforced tracking strip may be bonded to a side edge of the wide belt

The wide belt may be formed of homogeneous urethane or like material.

The method may include the step of forming the at least one reinforced tracking strip with at least one tracking protrusion. The tracking protrusion may be formed in a U or V shape.

Preferably, the method includes the step of providing both side edges of the wide belt with reinforced tracking strips.

The detailed description of the present invention is directed to a wide belt assembly for use as a multipurpose self-propelled tool carrier. Such a wide belt assembly may be used for, but not limited to, carrying equipment or machines for harvesting, selective tea plucking, track opening, pruning, levelling, fertilizing & spraying, the equipment or machines being supported by the wide belt on top of a tea bush canopy or on other plant material. However it should be understood, that the present invention is applicable to any type of belt assembly wherein a wide belt is driven by a pulley or roller. The wide belt may or may not be used for the conveyance of materials or goods.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 a is an underneath plan of apparatus for use in the cultivation and/or harvesting of tea;

Figure 1 b and 1 c are side and end views of the support frame of the wide belt assembly of Figure 1 a;

Figure 2a shows a belt of the apparatus of Figure 1 with reinforced tracking strips;

Figure 2b shows an enlarged detail of the reinforced tracking strips;

Figures 3a, 3b and 3c show a tracking roller and support rollers for the belt of Figure 2;

Figures 4a, 4b and 4c show end, side and sectional views of fittings for shafts of the support frame;

Figures 5a, 5b and 5c show end, side and sectional views of an end fitting and a drive sprocket for a drive shaft of the apparatus;

Figures 6a to 6g show light weight fittings for the apparatus;

Figure 7 shows a drive roller of the apparatus with an idler attachment;

Figure 8 shows an enlarged view of the idler attachment;

Figures 9a and 9b show side and sectional views of a driven stub shaft;

Figures 10a to 10f show sectional views of fittings of the apparatus;

Figures 1 1 a to 1 1 f show sectional and end views of the fittings;

Figures 12a to 12e show further details of fittings for the apparatus;

Figure 13 shows a fitting for brace wires of the apparatus;

Figure 14 shows an engine mounting for the apparatus;

Figures 15a and 15b show side and end views of a mounting and transmission for the apparatus; Figures 16a to 16d show end, plan and side views of part of the transmission;

Figure 17 is a schematic drawing of a prior art belt assembly with a long, narrow belt and a crowned pulley for tracking;

Figure 18 is a view showing the self-tracking of the belt assembly of Figure

17;

Figure 19 is a schematic drawing of a wide belt assembly with a crowned pulley;

Figure 20 is a schematic view showing deflection of a small diameter roller in a wide belt assembly;

Figures 21 A and 21 B show a wide belt extending around a prior art type roller.

Figure 22 is a plan view of a wide belt assembly for a tea harvester;

Figure 23A is a section through a reinforced tracking strip for a belt in accordance with a preferred embodiment of the invention;

Figure 23B is a side elevation view of a reinforced tracking strip for a belt in accordance with another preferred embodiment of the invention;

Figure 24 is a side view of an extrusion die for forming the tracking strip of Figure 23A;

Figure 25 is a section on the line A-A of Figure 24;

Figures 26, 27A and 27B, 28 and 29 are views of a guide assembly for positioning reinforcing fibres or cords in the extrusion die of Figure 24 and 25;

Figure 30 is a view of the tracking strip forming assembly;

Figure 31 is a side view of the tracking strip forming assembly of Figure 30; Figure 32 is a section through a drive roller having roller end members in accordance with a preferred embodiment;

Figure 33 is a section through an idler roller having roller end members in accordance with a preferred embodiment;

Figure 34 is an enlarged section through one of the roller end members of Figures 32 and 33.

Figure 35 is an enlarged section showing a bearing assembly of one of the roller end members. Figure 36 is a section through a roller end member of the drive roller having a keyed guide shaft.

Figure 37 is a section through a roller end member of the idler roller provided with an adjustment device.

Figures 38-39 are views showing apparatus for adjusting the tension of the belt.

Figures 40-42 are views of apparatus for bonding tracking strips to the side edges of a wide belt to provide the required accuracy of position of placement.

Figure 43 is a schematic diagram of the relative positions of the rollers in the apparatus of Figures 40-42.

DESCRIPTION OF PREFERRED EMBODIMENTS:

Fig 1 shows apparatus for use in the cultivation or harvesting of tea comprising a support platform. In use, the support platform is adapted to extend above and be supported on a canopy of tea bushes to support equipment and tools for cultivating or harvesting tea. The support platform includes two relatively wide support belts 1 and 2 provided on a light weight rigid support frame 3 with an open area 4 between the first belt 1 and the second belt 2. The open area 4 may be used in the support and transport of levelling and harvesting equipment. The support platform provides a uniform distribution of weight across the support area and prevents pitching along the longitudinal direction of travel and from rolling across the axis of longitudinal travel providing a levelling effect of the tea canopy.

The relatively simple and light weight construction provides an entry level machine for the mechanisation of tea estates which can be readily transported to the tea canopy and lifted onto the tea canopy simply by hand. The belts 1 and 2 are propelled by a drive assembly 5 and the apparatus may be steered simply by manually moving the front of the support frame 3 and the first belt 1 left or right.

In one preferred embodiment guidance devices 70 and 71 engage in the tracks between tea bush hedge rows for automatic steerage across the tea canopy without manual steering thereby not requiring any manual attention across the tea fields other than stopping and turning the apparatus at the ends of a field of tea bushes. The construction of the support frame 3 is preferably free from welds and may be simply assembled by means of tubes 6 being inserted into fittings 7a to 7f, and 20a to 20g.

The support frame 3 is preferably cross braced with tension wires 8a to 8g as shown in Figs 1 b and 1 c, and turnbuckles may be used to tension the wires. To achieve high floatation on the tea canopy and to spread the load across a large area it is necessary to use wide belts which historically are difficult to remain aligned.

In one preferred embodiment as shown in Figs 2a and 2b has at least one of the first and second belts 1 and 2 has at least one tracking strip 1 1 , 12. The or each tracking strip 1 1 , 12 is fitted with reinforcement strips 9 and 10 on each side of the central portion 14 of the tracking strip 1 1 , 12. The reinforcement strips 9, 10 may be reinforced with a plurality of fibres, wires or cords as shown in Figure 2b. The reinforcing fibres wires or cords may be made from Kevlar, carbon fibre, steel or other high tensile material.

Referring to Fig. 3, in order to preserve alignment a tracking roller 13a, 13b is provided to deform the central portion 14 between the reinforcements 9 and 10 of each tracking strip 1 1 , 12. Further support across the belt is provided by support rollers 15, 16, 17 and 18 in addition to the tracking rollers 13a and 13b. In a further embodiment of the invention the support rollers 15, 16, 17 and 18 may be replaced with long rollers [not shown] for full belt support between and each side of the tracking rollers 13a and 13b.

The difficulty in tracking wide belts in particular near square belts with the belt width close to the belt length is due to any variation from the length of one side of the belt to the other or caused by uneven tension across a singular roller. This causes the belt, over a number of revolutions, to build differential tensions across the belt causing it to run out of alignment. By using individual tracking rollers 13a and 13b and intermediary independent support rollers 15, 16, 17 and 18 across the belt this then allows the forces to neutralise and maintains straight tracking of the belt.

Fig 4 shows a fitting 20a-20g for a rotatable transverse member 19 of the lower part of the generally rectangular support frame 3. The rotatable member 19 of the lower part of the rectangular frame 19 serve a dual purpose of taking torsional and bending forces imposed on the frame as well as providing a rotating member as a support roller above the lower surface of the support belts 1 and 2. This also provides fast initial assembly and for repairs and maintenance allowing ease of belt removal and support roller replacement. Fittings 20a to 20g are provided with bearings 21 , a bearing retainer block 23 and a clamp plate 22 held by bolts 24 which restrain all forces but allow rotatable member 19 to freely rotate. The end 25 of the rotatable member 19 is bonded to a carbon fibre shaft 26 received in the bearings 21 . A compression ring 31 may be fitted over the end of the tubular rotatable member 19 to assist in securing the rotatable member 19 to the shaft 26.

The fittings 20a to 20g are attached to the vertically extending members of the light weight tubular frame 6 by pushing the vertical members into sockets 27 of the fittings.

The fittings 20a to 20g allow the transverse rotatable shafts 19 to act as idler rollers for the support belts at all locations over the tea canopy and also to withstand all the various diverging forces encountered by the frame in the course of operation.

Fig 5 shows one of the end fittings 30a, 30b for a driven rotatable member 19a of the support frame 3. An end of driven rotatable member 19a is fitted to a drive shaft 28 rotatably mounted in end fitting 30a, 30b. The drive shaft 28 has a drive sprocket 29 attached to it. The end fittings 30a and 30b are otherwise the same construction as the fittings 20a to 20g, and corresponding reference numerals have been applied to corresponding parts.

The housings for the fittings 20a to 20g may be formed as light weight fittings by injection moulding. Figures 6a to 6h show construction details for an injection die moulded light weight fitting 20a - 20g in the form of a T-piece with socket locations 32, 33 and 34 and retention holes 35, 36 and 37.

Fig 7 shows the drive roller 19 with carbon fibre tube idler attachment shaft 25 and driven end 28.

Fig 8 shows an enlarged construction detail of the idler end 25 having bearing lands 38 and 39 and a tapered wall 40 to reduce weight and provide for areas of stress under operation.

Figs 9a and 9b shows an enlarged view of the driven stub shaft 28. Figs 10a to 10h show the construction details and sectioned views of fittings 7a to 7f.

Figs 1 1 a to 1 1 show the detail and sectioned views of fittings 41 a and 41 b at the upper front and rear ends of the support frame 3.

Figs 12a to 12e shows fittings 42a and 42b at the lower front and rear ends of the support frame 3. They also detail the location for fitting bearing and belt movement for tensioning the belt in the direction of the arrow 64.

Fig 13 shows how the diagonal brace wires 8a to 8g, which extend between the upper and lower parts of the support frame, are connected to the fittings 7a to 7f, 20a to 20g, 30a, 30b, and 41 a, 41 b. The brace wires are used to prevent elongation of each of the sections meanwhile utilising the force to pull and reinforce the bearing housing by applying loads in the direction of arrows A. This is duplicated on both sides of the structure with the tension being induced by a singular turnbuckle by the tension on 8 being transferred around bolt 43a and 43b through holes 44a and 44b. The vertical members 45 are connected to the fittings via bolt (46).

The tension of brace wires pull all the support frames into the fitting. The brace wires 8f and 8g brace the frame in every direction to provide a stiff, light weight frame.

To allow low cost fully knocked down transport and to provide low cost on- site assembly welding has been eliminated from the construction of the apparatus. As an example Fig. 14 shows an engine mounting 47 which may be comprised of an upper plastic frame part 48 and a lower part frame part 49 which clamps around a tubular member of the frame 3 at locations 50 and 51 by bolts 52, 53, 54 and 55. An engine may be attached to the engine mounting 47 via bolt holes 56 and 57.

Figs 15a and 15b show a transmission 58 and transmission mounting for the apparatus. The high reduction from the engine is transferred via the transmission 58 which is clamped onto the frame via clamps at 59 and 60.

Figs 16a to 16d show respectively end elevation, side elevation and plan views of part of the transmission 58 and a mounting 61 , and Fig 16d shows a gear wheel 62 of the transmission. Fig 17 shows a drawing of a prior art belt assembly 101 , comprised of a crowned pulley 102 and a long flat belt 103.

Fig 18 shows the self aligning characteristics of the crowned pulley 102 and the long narrow belt 103 of Fig 17. When the belt 103 starts to run off the belt pulley 102, in this case shown as position 104, the belt 103 follows the crown of the pulley at 105 causing the belt to bend at 106. This bending action at 106 causes the belt edge at 107 to move across from the position 104 to be re established at position 106 which moves the belt across the distance as shown in (B) at 107.

Fig 19 shows the case of a very wide short belt 1 10 that the roller 1 1 1 is holding the belt taut in the direction of arrow 1 12 preventing the belt moving against the minimal crown distance shown at 1 13 and is not able to transfer the body of the belt in the direction of the arrow 1 14. This means that the edge of the belt at 1 15 remains in the same position and therefore will remain in the same position at 16. This means that a wide relatively short belt as shown in Fig 19 does not respond to a crowned roller and will continue to track off line.

Fig 20 shows a roller and belt assembly 1 17 from a plan view perspective. For weight reduction and for gearing ratio it is necessary to maintain a small diameter roller 1 1 1 . Even with an increase in the central diameter of roller 1 1 1 as shown as (A) 1 18 to crown the roller, when sufficient belt tension shown by arrows 19 is applied to the belt roller 1 1 1 the small diameter roller will deflect in the direction of arrows 1 19 causing the original convex crown roller to deflect below line 120 to the position shown at 121 . This causes the shape of the roller relative to the belt to be concave and results in a reversal to the crowned shape required for automatic tracking.

Fig 21 A shows a cylindrical roller 1 1 1 fitted with a thin belt 1 10 which has a 180 degree frictional contact with the roller 1 1 1 across the full width as shown by arrow A-B at 122. This precludes any effective use of edge belt side guides as shown in the enlarged view of an end of the belt 1 10 and roller 1 1 1 in Fig 21 B. The force required at (C) 123 to overcome the frictional effect between the belt 1 10 and roller 1 1 1 as shown at (A-B) 122 cannot be sustained at the edge of the thin belt 1 10 shown at (C) and will simply deflect and roll over at the area of force at 23. Fig 22 shows a self propelled apparatus 124 for use in harvesting tea including a belt assembly. The machine includes wide belts 127 and 128 supported solely on the tea bush canopy by a forward conveyor assembly 125 and a rear conveyor assembly 126. In both instances, it is difficult to maintain alignment and tracking of wide belts 127 and 128 when using conventional methods to maintain belt alignment.

Fig 23A shows one preferred embodiment of a reinforced tracking strip 132 for a belt preferably formed of homogenous urethane 129 longitudinally reinforced with a plurality of reinforcing fibres, wires or cords 130. The fibres, wires or cords may be made of Kevlar, carbon fibre, multi strand steel wire or cord or other high tensile fibre. As shown in Figure 23A the tracking strip has a substantially flat surface 320 on one side and a trapezoidal shaped tracking protrusion 131 extending from the opposite side. The protrusion 131 is located substantially midway along the tracking strip 132 with flat surfaces 321 ,322 on both sides of the protrusion 131 . The tracking protrusion 131 is an integral part of the reinforced tracking strip 132. The reinforcing fibres or cords 130 are provided at spaced intervals along the whole width of the tracking strip 132 so that the strip is substantially inextensible. Although a trapezoidal shaped protrusion 131 is shown in Fig 23A, the protrusion may take other shapes, such a V-shape, a U-shape or a square shape.

Figure 23B shows a side view of a tracking strip 132 of another preferred embodiment having notched sections 74 at intervals along the entire length of the tracking protrusion 131 to provide flexibility when used with small diameter rollers. As in the embodiment of Fig 23A, the tracking strip 132 may be made of homogenous urethane 129 reinforced longitudinally with a plurality of fibres, wires or cords (only one of which is shown in the side view of Fig 23B.

To enable the production of a homogenous assembly of urethane and reinforcing fibres all of which are to be at a common tension and accurately contained central to the protective urethane or other flexible material, it is necessary to provide a means of manufacture to produce an accurate product with the required characteristics. Figs 24, 25, 26 and 27A show different views of extrusion die assemblies 33 for manufacturing the tracking strip of Fig 23. Fig 24 shows a side view of the extrusion die, having a section line (A-A) at

134.

Fig 25 is a section on the line A-A of Fig 24. This shows the flow control 136 and 137 method for the various sections of the tracking strip. This controls the uniform flow of material into gallery 138 and 139 which in turn accurately feeds the required material to the forming die cavity shown in Fig 27A at 140 and 141 . This enables the formation of a uniform homogenous product on a continuous basis.

Fig 26 shows a reinforced forward guide assembly 142 and the positioning of the multi strand fibre cords at 143. This assembly is shown more clearly in Fig 27B.

Fig 28 shows a sectioned view of the split halves of the guide assembly 142 and in particular the aperture to receive the cords in detail at 144.

Fig 29 is an end view of the guide assembly 142.

Fig 30 shows a tracking strip forming assembly 145. The tracking strip 129 of Fig 23 is roll formed by the machine 145 by rollers 146, 147 and 148. The final forming after extrusion requires careful temperature control which is carried out by providing temperature controlled water via a rotary union at 149, 150 and 151 which flows around the parameter around the outside of internal shapes 152, 153 and 154 to exit via the galleries in the shaft at 155, 156 and 157.

Fig 31 is a side view of the forming assembly showing the product flow and entry from the extrusion dies at 158 in the direction of arrows 159 and exiting at 160. Cylinders 161 and 162 provide the force to hold rollers 146 and 149 against stops at the correct relative distance to form constant thickness flexible material that encompasses the Kevlar cord or other high tensile fibres.

Fig 32 shows one preferred embodiment of the means for providing tracking engagement for a wide belt. A drive roller assembly 163 includes a central tubular roller portion 164 and roller end members 165 and 166. The central roller portion may be formed from a Kevlar, carbon fibre, high tensile aluminium or other light weight strong tube 164. In one preferred embodiment a tube 164 of high tensile light weight material, such as aluminium is bonded into the roller end members 165 and 166 to provide accurate location of the end members 165 and 166. For the drive roller assembly 163, the end member 165 has a short shaft at 167 the end member 166 has a long keyed shaft at 168 to accommodate the driving means.

Fig 33 shows an idler roller assembly 169 which includes a central tubular roller portion 164 and identical roller end members 165 at each end. The idler roller assembly may be formed in the same way as the drive roller assembly 163. The roller end members 165 on both ends both have a short shaft 167. Each of the roller end assemblies 165 and 166 shown in Figs 32 and 33 have guide grooves or recesses 170 for engagement with a complementary shaped tracking protrusion of a tracking strip as shown in Fig 23.

Fig 34 is an enlarged view of the idler roller assembly 169 showing the tubular central roller portion 164 of carbon fibre or other light weight tubular material and a roller end member 165 which may be made of high tensile aluminium or other light weight material. The end member 165 has a shaft 167, a bearing retention thread 171 , a tracking groove 170 and a recess 172 which encapsulates the end 146 of the tubular central roller portion 164 at 173. This helps to prevent delamination of the end of the central roller portion 64 in the case that it is formed from a carbon fibre tube.

Fig 35 is a view of a tracking end assembly 169 on one of the roller end members. The tracking end assembly 169 includes a retention bolt 174, bearings 175 and 176, a bearing spacer 177, a bearing housing frame connector 178, a retention plate 179 and retention bolts 180 and 181 . The bearing housing frame connector 178 may be injection die moulded.

Fig 36 shows an enlarged view of the end of the drive roller assembly 163 with the tracking protrusion 129 of the reinforced tracking strip 132 engaged in the guide groove 170 of the roller end member 66 with the keyed guide shaft 168. Fig 120 also shows the belt 127 and 218, the tubular central roller portion 164 and a deliberate gap or clearance between the outside of the central roller portion 164 and the inside of the belts 127 and 128 shown at 182. This provides for the only frictional contact being via the surface of the tracking strip 132 shown between the arrows 183 and 184. This means that any variation of belt length at the sides of the belt can be adjusted by minimal frictional slippage on both ends of the drive roller assembly 163 by slippage only over the drive area between 183 and 184. Fig 37 shows an adjustment device for the non-driven idler roller assembly 185 having a bearing housing 186 fitted with bearings 187 and 188, a bearing spacer 189, and an assembly spacer 190 connected to a threaded rod 191 which is used for the purpose of adjusting the belt tension.

The transverse and diagonal forces that would otherwise build in the belt from variation of belt side length or unequal tensioning can be equalised by a free running roller assembly 221 engaging with the tracking strip 132. The area of engagement of the tracking strip 132 with the roller assembly 221 between 183 and 84 is isolated from any torque forces by bearings 192 and 193.

Fig 38 shows the belt adjuster 191 and assembly 185 in conjunction with a supporting frame 192 and side guard cover 193 which prevents the entry of extraneous materials, such as tea leaves in the case of a wide belt assembly used on and supported by the tea bush canopy. The tea leaves are prevented from reaching the covered edge of the belt 222 by the flanged cover 193 encapsulating and covering around the complete belt inboard to 223.

Fig 39 shows the supporting frame 192, an adjustment and junction 194 connected to the frame 92, a belt tension adjuster 191 , lock nuts 195 and 196, a fixed guard 193, and a moveable enclosure 197 which slides over fixed guard 193 when the belt tension adjuster 191 is used.

Figs 40-42 shows apparatus 198 for bonding tracking strips to belts with a high quality bond, an accurate distance from each side of the belt edge and accurate tracking strip centre distances. Such an apparatus achieve economical manufacture. The end view of Fig 40 shows that the apparatus 198 includes a frame 199 with bearings 200 and 201 supporting tubular rollers 202 and 203 which are fitted with edge guides 204, 205, 206, 207 and a tracking protrusion to accommodate the tracking strip at 208, 209, 210 and 21 1 .

Fig 41 shows the frame 199, and rollers 202, 203, 212, 213, 214 . Each roller is preferably a lagged roller with a steel band at either end under the area in which tracking strip applicator rollers 215 position the tracking strip accurately while bonding to the belt. A roller 216 is attached to frame 217 which travels from 218 to 219 to obtain the correct position for the front belt 127 and rear belt 128 as shown in Fig 27. An air cylinder 220 is provided with a control valve to obtain the different positions between 218 to 219 and a pressure regulator to adjust the pressure applied to the belt at roller 216.

Fig 42 is a plan view of the apparatus 198.

Fig 43 shows the positions of rollers 202, 203, 213, 214, 212 and 216 and relative position of belt 127 and 128.