WO2000072659A1

WO2000072659A1 - Tea harvester

Info

Publication number: WO2000072659A1
Application number: PCT/AU2000/000605
Authority: WO
Inventors: Geoffrey Allan Williames
Original assignee: Williames Hi Tech International Pty Ltd
Current assignee: Williames Hi Tech International Pty Ltd
Priority date: 1999-05-26
Filing date: 2000-05-26
Publication date: 2000-12-07
Anticipated expiration: 2001-11-26
Also published as: AUPQ058299A0

Abstract

A tea harvester is disclosed that is partially supported in the tea bush canopy and is partly supported from the ground, the harvester having a main support frame (1), a tea leaf cutter arrangement (42) supported from and forwardly of the main support frame (1) a guide assembly (4) depending from the main support frame (1) for passing over and resting on the upper region (79) of the tea bush canopy, and additional support means including wheels (11, 28, 81, 85b) connected to the guide assembly to provide additional ground support for the harvester.

Description

TEA HARVESTER BACKGROUND

The present invention relates to improvements to tea harvesting machinery.

Australian Provisional Patent Application No. PP7103 and International PCT Patent Application No. PCT/AU92/00376 disclose various embodiments of tea harvesters for use in the collection of tea leaves from tea bushes. These references discuss the use of a tea harvester which is supported in use solely by the tea bushes from which the leaves are being harvested. These constructions provide advantages as set out in the respective specifications. The subject matter of the aforesaid patent references is incorporated herein by this reference thereto.

Other tea harvesters have used wheeled machines with pneumatic tyres, and these have generally been associated with an unstable platform due to undulations in the surface on which the wheels are running, which translate directly to undulating movement of the harvesting head attached to the main frame. This results in the harvesting mechanism not being controllable relative to the level of the upper surface of the tea bushes in respect to the level of the previous harvest round. That is, the height of harvesting of the tea is not controlled in relation to the height of the bush itself, but rather in relation to the undulations in the ground surface. This means that, instead of only harvesting the young growth, approximately two leaves and a bud which provide the highest quality tea, the upper maintenance foliage of dark green over-mature tea leaves are harvested together with the proper quality upper leaves causing irreversible damage to the quality of the harvested leaf. A further serious problem of the variation and fluctuation of the harvesting height can result in the undesired harvesting of new buds from the mature parts of the bush which would provide the next generation of plant shoots, and this overharvesting can seriously deplete the number of young fresh shoots to be harvested on the next harvest round thereby reducing yields. Pneumatic tyres due to their compressible nature can also result in the machines swaying from side to side, causing the outside edges of the harvesting means to alternatively dip into and out of the correct harvesting level of each side of the upper surface of the tea bushes. It is an object of the present invention to provide novel means for maintaining the height of the harvesting machine head more correctly at a desired level with respect to the height of the previous harvest round to achieve improved efficiency in harvesting and improved quality harvested tea. Accordingly, the present invention provides features and aspects as defined in any one of the claims annexed hereto or any one or more of the features either singly or in any combination as hereinafter described.

According to a first embodiment of the present invention, there is provided a tea harvester having: a main body; a harvest cutting device; guide means depending from the main body for passing over and resting on the upper region of a canopy of tea bushes; additional support means for supporting the main body including a wheeled frame adapted to allow the additional support means to roll over the ground below the tea crop.

Preferably the main body of the tea harvester is adjustable in height with respect to the wheeled frame. Preferably such height adjustment is enabled by the provision of a winching mechanism operable to lift the main body of the tea harvester with respect to the wheeled frame. Preferably there is provided rotatable support means between the wheeled support means and the main body.

Preferably the guide means is operable to control the height of the harvest cutting device with respect to the upper region of the canopy of the tea bushes. Preferably the harvest cutter means is supported between the main body and the guide means.

Preferably at least one wheel of the wheeled frame includes a steering mechanism for the purpose of enabling steerage of the main body of the tea harvester.

Preferably the wheeled frame includes three wheels, with two of the wheels at a forward end of the wheeled frame. Preferably the rear wheel forms part of the steering mechanism. Preferably at least one wheel of the wheeled frame is powered by a motor to drive the tea harvester.

Preferably, where a fourth wheel is provided, this fourth wheel is rotatable about a vertical axis to allow free castoring of the fourth wheel. Preferably at the front and rear wheels of one side of the tea harvester have axes that are fixed in relation to each other, but are attached to a common structural member which is rotatable with respect to the wheeled frame.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a wheeled mechanism for supporting a tea harvesting device in accordance with a first embodiment of the present invention;

Figure 1A is a side elevational view of a tea harvester incorporating the wheeled mechanism of Figure 1 ;

Figure 1 B is a perspective view similar to that of Figure 1 of a second embodiment of the present invention;

Figure 1C is a perspective view similar to that of Figure 1 of a third embodiment of the present invention;

Figure 1 D is a side elevational view of the third embodiment of the invention shown in Figure 1C; Figure 2 is a partial elevational view of a drive mechanism for use with embodiments of the present invention;

Figure 3 is a partial end view of the drive mechanism of Figure 2;

Figure 4 is a perspective view of a tiller arrangement for use with embodiments of the present invention; Figure 5 is a side elevational view of an alternative roller section for use in conjunction with embodiments of the present invention;

Figure 6 is a perspective view of a cutter bar mechanism for use with embodiments of the present invention;

Figures 7 and 8 show partial side elevational views of the cutter bar device of Figure 6 in operation with respect to tea bush foliage;

Figure 9 is a perspective view of an alternative cutter bar device; Figure 10 is a partial perspective view of cutter blades of a further alternative cutter bar device;

Figure 11 is a side elevational view of a conveyor roller mechanism for use with embodiments of the present invention; Figure 12 is a perspective view of a leaf conveyor mechanism for use with embodiments of the present invention; and

Figure 13 is a perspective partially cut-away view of a cutting head roller assembly in accordance with an embodiment of the present invention.

Referring firstly to Figures 1 and 1A, the tea harvester illustrated consists of a height adjustable platform (1) on which the cutter/conveyor (2) and cutter self- levelling head rollers (3) are mounted. This platform (1 ) is connected to a main frame assembly (4) by means of rollers (5) and winch assemblies (6a). These rollers (5) bear and run on the vertical masts (6b) which are part of the main frame assembly (4). In these vertical masts (6b) are a series of drilled holes (7) which allow accurate height control by means of removable stops (8) which can be placed in any row of holes. Once these stops (8) are correctly positioned the height adjustable platform can be lowered onto these stops by means of the winches (6a). Positioned on the top rails of the work platform (1) are guides (9) to locate the tea collection bags (10). A single steerable rear wheel (28) is mounted in line behind the front drive wheel (11). Steering is achieved by a simple tiller arrangement (29), which is illustrated in more detail in Figure 4. The tiller arrangement (29) consists of a vertical square tube (30) welded to the rear fork assembly (31). This vertical square passes through a round tube (32) which includes two polyethylene/nylon bushes (33) and an internal steel bush (34) which the tube (30) passes through. On this vertical tube (30) the tiller handle (35) is secured by means of a lock nut (36). This tiller handle can be raised and lowered with the work platform.

Figure 1A shows rollers (3a and 3b) connected to arm (72) that is connected to the opposite side arm via a torque tube to ensure both side arms (72) and rollers (3a, 3b) remain parallel to each other at all times. The assembly of rollers (3a, 3b) and arms (72) are attached to the frame (73) by means of pivotal points (74) on each side of the assembly. This allows rollers (3a, 3b) to act as a tandem roller support assembly to roll across the surface of the unharvested tea bushes to offset the effect of any holes or irregularity in the tea bushes by rollers (3a, 3b) oscillating up or down independently of each other about axis (74) and by this means minimize the amount of height variation of pivot (74) and frame (73). The harvesting or cutter conveyor assembly (75) pivots about axis (76) that in turn is fixed to frame (1). The roller assembly (77) frame (73) and cutter conveyor assembly (75) are positioned so that the pivotal axis (76) is just off the centre of balance causing the rollers (3a, 3b) to rest relatively lightly on the upper surface of the tea bushes. This ensures tea cutter (42) remains generally at the correct harvesting level in relation to the surface of the tea bushes (78). By extending or contracting turnbuckle (71), cutter (42) can be raised or lowered with respect to the existing level of tea bushes (78), allowing control of the height of the bush after harvesting (79). This ensures next generation buds are not damaged giving higher yields and importantly ensures dark green mature maintenance foliage is not harvested and that only fresh young top quality tea is harvested giving higher quality harvested leaf.

The harvesting cutter blade (42) is mounted approximately at the mid point between the axis (74) of roller assembly (27) and the wheel (11) contact point on the ground (80). This means blade (42) has a grading - levelling effect providing a more level upper surface to the canopy, thus benefiting future harvests.

Figure 1 B shows an embodiment including a fourth wheel (81) that adds stability and ensures ground contact of drive wheel (11) by means of arm (82) which is connected to frame (1) at pivotal point (83) and is supported by spring and/or air shock absorber assembly (84). The wheel (81) is pivotally connected at axis (85a) in a vertical plane to allow wheel (81 ) to castor freely allowing steerage by the singular steerable wheel (28).

Although the three wheeled embodiment shown in Figure 1 is the preferred embodiment for simplicity and lower costs, the invention may clearly be used with four wheels with various means of steerage and suspension. Figure 1C shows a tandem wheel assembly for self levelling minimising movement of frame (1) by allowing wheels (85b) and (81) to oscillate over uneven ground and to give three points of support to the frame (1) at (86), (87) and (88). Wheel (81) will be pivoted about vertical axis (85a) to allow castor steerage or interconnected by suitable steerage linkage (not shown) to the steerable wheel (28). This configuration allows uniform pressure on wheels (28), (81), (85b), (11) independently of ground surface undulations. Figure 1 D shows the effect of the multiple pivotal assemblies (77, 75 and

88) as follows. Wheel (81) and (85b) are connected to arm (89) that is pivoted about axis (90). This has the effect that if wheel (81) or (85b) go over a bump, pivotal point (90) and frame (4) is only raised half of the distance. Thus pivotal point (76) only raises the body of the harvester assembly (75) half the distance. The roller assembly (77) however remains on the top of the previously harvested level of the upper surface of the tea bushes and thus controls the cutting harvesting point (42). The net effect is that the invention provides control of the cutting height of the harvesting head relative to the upper surface of the tea bushes without substantial effect normally experienced on wheeled harvesters from travelling over uneven ground surfaces and transferred from the compressibility of pneumatic tyres.

Figure 5 shows the frame (73) fitted with a longitudinal adjustment (91). This allows adjustment of the position of roller assembly (77) relative to the cutter (42) of Figure 1 D, and wheel contact point (80) to give optimum control of the self- levelling characteristics of the invention to grade and level the tea canopy independently of reasonable ground variation and to ensure optimum control of the harvesting cutter (42) relative to the tea bush upper surface (78).

A drive transmission (12) shown in Figures 2 and 3 includes an independent motor (13) provided to drive the drive wheel (11). The transmission further includes a V-belt (14) driven by the motor (13) and via cone V-belt pulleys (15), so that speed ratios can be changed, driving a primary shaft (16). On the outer ends of the primary shaft (16) are V-belt pulley wheels (17), adapted to receive V-belts (18). Adjacent to but inwardly of the pulley wheels (17), is a roller (19), having a compressible material on the rim (such as polyurethane, rubber or friction material). From the primary shaft (16), the V-belts (18), are arranged to drive pulley wheels (17), on intermediate shafts (20). On the inner ends of the intermediate shafts (20), is a first sprocket (21) which drives second sprocket (22) connected to the shafts of the wheel (11) via chains (23). Finally, on the intermediate shaft (20) there is provided a steel run roller (24) aligned with the roller (19) on the primary shaft (16). Connected to the roller is a brake (not shown) which may be used as a parking brake. The function of the drive transmission is as follows. The transmission is operated by one lever (25) (see Figure 3) with a linkage (26) to the primary shaft (16). If the lever (25) is pushed forward the linkages (26) raise the primary shaft which drivingly engages the V-belts and causes forward movement. This position is maintained via spring tension applied by springs (27). If the lever is pulled back to a vertical position, the V-belts (18) are disengaged from driving the pulleys and the machine is placed in neutral disengaging the belt (18) from the drive motor (13). If the lever (25) is pulled back towards the operator, this engages the two rollers (24) and (19) causing reverse motion to be applied to the drive wheel (11).

The cutter bar assembly (45) shown in Figure 6 includes three lateral crossbars (41) which run full width across the harvester, onto which the cutter blades (42) are bolted. These lateral bars (41), in one preferred embodiment, are placed at 120 degrees to each other and are connected to each end hub 43 via connecting bars (44). The cutter bar rotor assembly (45) is hollow in the centre (that is, no central shaft) to allow the entrance of the tea to the cutter bar assembly (45). In Figure 7, there is shown in partial sectional view, the direction of travel of the cutter bar assembly (45) and the tea foliage enclosed within the cutter rotor assembly (45) and the cutter bars rotating around the outside of the foliage in the direction of the arrow, and in Figure 8 is shown the cutter bar (42) cutting edge intersecting with the cutter bar anvil (46) and tea foliage stem, consequently cutting the tea foliage. To ensure torsional integrity triangular braces (47, shown in Figure 6) are welded to the cross bars (41) in one or more positions. In one embodiment one central triangular brace (47) is used with a corresponding horizontal forward facing V (50) which is attached to, or is part of, the lower cutter bar anvil (46) protruding forward of the cutter separating the foliage from the triangular brace (47). The novel feature of the hollow cutter bar rotor in lieu of a central through shaft is that a central shaft pushes the tea over in a forward direction causing it to remain outside the cutting members, missing long stems of tea. Figures 7 and 8 shows the results of the open centered cutter which ensures a clean cut of the full length of tea foliage.

Referring to Figure 9, there is shown a partial view wherein the cutter bar cross bars (41) are angled out toward the direction of cut to a central peak (49) this produces a scissor type action as the rotor blades (42) sweep past the anvil blade (46). In the centre of the anvil blade (46), matching the peak of the rotor bars (49) is a cutter bar guide (50) or forward facing V, as described above, which protects the blades (42) on the rotor from engaging against the front face of the anvil blade and it also acts as a guide to direct the tea into the path of the rotary blades at the joint point of the diverging angular blades at (49). The increased section of the cross bars (41) at the centre section reduces deflection at the central highest point of loading.

In another embodiment, shown in partial view in Figure 10, there are a number of peaks (51) on the cross bars (41) of the rotary cutter at specified distances apart, and on the anvil blades are guides (52) placed at the same distance as the peaks to guide the blades and direct the tea into the path of the blades. This allows for a multiple of scissor type actions across the full width of the cutter bar. The blades (53) are shaped to allow for the radius of the cutter assembly, so that the blades engage against an anvil cutter blade (42) and cut precisely and cleanly over the full width.

As shown in Figure 6, on each end of the cutter bar is a sprocket (54) which carries the chain (55) on which the conveyor cleats (56) are attached. The cleats which run full width of the cutter bar rotcr assembly (45), are spaced and timed to fit neatly behind each of the cutter bar cross bars (41), one cleat behind each cross bar. As the tea is cut, the cutter bar assembly (45) sweeps the cut tea onto the conveyor frame (57) and rotates out of the way. But as the conveyor cleat (56) is immediately behind the cross bar (41), as shown in Figure 11 , this cleat comes into contact with the cut leaf (58) and elevates the cut leaf up the conveyor frame (57). In another embodiment the leading edge of the elevator cleat closest to the cutter bar cross bars is radiused to fit very closely behind the cross bar (41) the radius being equal to the passage of the elevator cleat as the conveyor chain leaves the cutter/conveyor and proceeds up the conveyor. The combination of the hollow rotary cutter assembly (45) and the conveyor with full width elevator cleats (56) which run around and within the outer circumference of the cutter bar assembly (45) is novel and unique. It allows for a lightweight and gentle method of cutting and conveying high quality tea leaf as a combined process. Attached to the bottom edge of the conveyor frame is the cutter anvil (54), on which the adjustable anvil cutter blade (42) is bolted. It is so positioned that the tea foliage comes against this fixed blade and as the rotating cutter bar assembly (45) rotates, each bar (41) with its cutter blade (42) sweeps past the anvil blade (46) and subsequently cuts any foliage trapped therein. On one side of the cutter bar assembly and in one preferred embodiment, is a drive mechanism (60), which consists of a small engine and V-belt or chain drive or other means which is connected to the cutter/elevator drive shaft.

The leaf conveying means shown in Figure 12 includes an external framework (61), the cleated conveyor chain (55) and the fixed cutter bar anvil (59). In one preferred embodiment the framework is manufactured using the same method as the longitudinal beams of the main frame, that is, sheets of EPS with lightweight thin high tensile aluminium sheet glued to either side with an upper and lower channel cap bonded to the EPS and fastened to the high tensile aluminium side sheets. Attached to the floor of the conveyor frame are two strips of high- density polyethylene (62), or equivalent material on which the conveyor cleats (56) slide on their way up the conveyor frame. Mounted near the top of the conveyor frame vertical sides (63), one per side, are two more sections of polyethylene (64), which act as chain guides for the return chain.

The cutting head self levelling roller assembly, in one preferred embodiment shown in Figure 13 consists of an external frame (65) which supports a pivoted dual roller arrangement (66). These pivoted rollers (67) are constructed from lightweight high tensile aluminium sheet (68) formed around a series of polystyrene discs (69) connected to a central through tube (70). The function of these rollers is to both adjust the height of the cutter bar assembly mounted on the pivoted conveyor frame and to maintain a more even, correct picking height independent of tea canopy undulations. A top linkage is adjustable and able to be lengthened or shortened by means of a turnbuckle type arrangement (71) therefore either raising or lowering the picking head (2), as shown in Figure 1 A.

Although the embodiments proposed in this description refer to the use of dual rollers for the canopy height tracking mechanism, in some applications only one roller may be necessary.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A tea harvester including: a main body; a harvest cutting device; guide means depending from the main body for passing over and resting on the upper region of a canopy of tea bushes; additional support means for supporting the main body including a wheeled frame adapted to allow the additional support means to roll over the ground below the tea crop.

2. A tea harvester in accordance with claim 1 , wherein the wheeled frame is connected directly or indirectly to said guide means.

3. A tea harvester in accordance with claim 1 or claim 2, wherein the main body of the tea harvester is adjustable in height with respect to the wheeled frame.

4. A tea harvester in accordance with claim 3, wherein the height adjustment is enabled by the provision of a winching mechanism operabSe to lift the main body of the tea harvester with respect to the wheeled frame.

5. A tea harvester in accordance with claim 1 or claims 1 to 3, wherein rotatable support means is provided between the wheeled support means and the main body.

6. A tea harvester in accordance with any one of claims 1 to 5, wherein the guide means is operable to control the height of the harvest cutting device with respect to the upper region of the canopy of the tea bushes.

7. A tea harvester in accordance with any one of claims 1 to 6, wherein the harvest cutter means is supported between the main body and the guide means.

8. A tea harvester in accordance with any one of claims 1 to 7, wherein at least one wheel of the wheeled frame includes a steering mechanism for the purpose of enabling steerage of the main body of the tea harvester.

9. A tea harvester in accordance with any one of claims 1 to 8, wherein the wheeled frame includes three wheels, with two of the wheels at a forward end of the wheeled frame.

10. A tea harvester in accordance with claim 9, wherein the rear wheel forms part of the steering mechanism.

11. A tea harvester in accordance with any one of claims 1 to 10, wherein at least one wheel of the wheeled frame is powered by a motor to drive the tea harvester.

12. A tea harvester in accordance with any one of claims 1 to 11 , wherein, where a fourth wheel is provided, this fourth wheel is rotatable about a vertical axis to allow free castoring of the fourth wheel.

13. A tea harvester in accordance with any one of claims 1 to 12, wherein front and rear wheels of one side of the tea harvester have axes that are fixed in relation to each other, and wherein said front and rear wheels are attached to a common structural member which is rotatable with respect to the wheeled frame.