GB1599848A

GB1599848A - Mechanical digger and harvester for root crops

Info

Publication number: GB1599848A
Application number: GB1819878A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-05-12
Filing date: 1978-05-08
Publication date: 1981-10-07
Also published as: BR7803019A

Description

(54) MECHANICAL DIGGER AND HARVESTER FOR ROOT CROPS (71) We, HOWARD JAMES RICH TER and GRAHAM JAMES RICHTER, both of 2, Church Street, Boonah, Queensland 4310, Australia, and both Australian citizens, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a mobile digger and harvester for root crops, particularly for cassava root and arrowroot.

Cassava, as well as being a tropical food crop, has recently come into use as an important source of power alcohol, which involves large-scale digging and harvesting at the lowest possible cost. As an indication of the renewed interest in cassava. the global area under production has increased ten-fold in a period of only two years.

Various systems of mechanical digging and harvesting of cassava roots and arrowroot have been proposed, but none have been commerically successful. Two major difficulties arise. The roots grow deep e.g.

to a depth of 30-40cm. so that breaking of the soil to this depth is involved; this has to be done without undue strain on the machine or its tractor. Furthermore, the roots have to be lifted for harvesting to the surface without losing an appreciable proportion of the crop.

Previous systems have relied on the use of mechanical diggers and harvesters of the types used for other root crops, e.g. potatoes, carrots and parsnips. Because of these crops growing at shallow depth, the diggers and harvesters are of relatively light construction and are unable to withstand the strains imposed on the implement if required to operate at the depth of 30-40 cm.

necessary for cassava roots. Merely strengthening the components of these implements is not satisfactory.

Another problem with trying to adapt these known implements for digging and harvesting cassava roots is their inability to penetrate the soil to a sufficient depth and maintain the depth. In an effort to increase the penetration known diggers have been modified to have a high "angle of attack" of the share. Throughout the specification and claims, the term "angle of attack" of the share is defined to be the included angle between the digging share and the horizontal. This high angle of attack of the share results in the tendency of the share to dig deeper as the implement is moved until the share reaches a depth where the tractor can no longer pull the implement. If the angle of attack is reduced, the share will not penetrate the soil to the required depth.

It is an object of this invention to overcome these difficulties using a normal tractor and a relatively simple machine.

It is a further object to provide an effective harvester-loader for roots so dug.

It is a further object to provide simple and effective means to ensure that the digging share penetrates the soil to the required depth and is maintained at that depth.

It is a still further object of the present invention to provide a machine where the digging share has a very low angle of attack, eliminating wheel slip and drag while still maintaining the required depth.

Other objects of the present invention in its various forms will become apparent from the following description.

According to the present invention we provide a mechanical digger or harvester for root crops including: a frame; ground engaging wheels supporting the frame at at least one selected height above the ground; a digging share mounting on the frame; penetration means for forcing the digging share into the ground to a working depth; depth control means for controlling the penetration of the digging share into the ground to the working depth, wherein: the angle of attack of the share at the working depth is maintained at substantially zero.

The digging share may be mounted directly on the frame or through the agency of a subframe pivotally mounted on the frame.

The penetrating means may include weights on the frame; a hydraulic ram between the frame and subframe; or a hydraulic ram between the tractor and the lower links of the tractor three-point linkage on which the frame is mounted.

The depth control means may include an adjustable ground wheel on the frame, or the hydraulic rams may be of the doubleacting type.

The digger or harvester may be used as a trailed implement, mounted on the three point linkage of a tractor or as a selfpropelled vehicle.

The harvester may include an elevator to lift the roots dug by the digging share, and a sieve to clean the roots.

The digger or harvester may include coulters or discs, fixed tines, or a rotary pick assembly, either singly or in combination forwardly of the digging share.

To enable the invention to be fully understood, preferred embodiments will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of the first embodiment of the present invention; Figure 2 is a plan view of Figure 1 with parts removed for clarity; Figure 3 is a plan view of a second embodiment of the present invention; Figure 4 is a side view of Figure 3; and Figure 5 is a plan view of a third embodiment of the present invention.

Referring to Figures 1 and 2, the digger 10 has a main frame 11 including side rails 12 and end rails 13.

A triangular lifting frame 14 is mounted on the main frame 10 and has a pair of spaced vertical plates 15 at its apex. The plates 15 have aligned holes 16 adapted to accept a pin 17 rotatably mounted in the top link 18 of a tractor three-point linkage i.e.

the "Ferguson System"-type linkage. The lifting frame 14 has a pair of diagonal traces 14a which are fixed to the side rails 12. A pair of downwardly directed vertical plates 19 are provided at the base of the lifting frame 14. Each plate 19 has a horizontal pin 20 which engages a rotatable socket 21 in the lifting links 22 of the tractor three-point linkage. A pair of hydraulic rams 23 each have one end connected to a lifting link 22 and the other end connected to the chassis of the tractor via a mounting bracket 24.

A sub-frame is mounted on the main frame 11 between the side rails 12. The sub-frame supports a slat-type elevator 25 which passes around end sprockets mounted on shafts (not shown). The transverse slats 26 of the elevator are carried on driving chains 27 which are driven by the powertake-off of the tractor via a universallycoupled p.t.o shaft 28, a clutch 29 and a gear box 30. If preferred, the driving chains may be driven by ground wheels. A pair of side plates 31 are fixed on the sub-frame and run the length of the elevator. A digging share 32 is mounted on the sub-frame forward of the elevator 25. The share 32 has a curved leading edge (as shown in Figure 2) and extends transversely the full width of the elevator. The angle of attack of the digging share is set to be substantially zero e.g.

within the range of 0 to 15C to the horizontal) at the required working depth (see Figure 1).

The forward end of the subframe is supported by angled braces 33 fixed to the side rails 12.

A mounting bar 34 extends forwardly from approximately the mid-point of each brace 33 and is fixed with the outer sleeve of a bearing 35. A coulter 36 (or disc) is rotatably mounted on an axle 37 which is journalled in the bearing 35. Each coulter is mounted in front of the respective side plate 31 and cuts a groove in the soil (and through any roots it engages) to a depth substantially the same as the working depth of the digging share 32. The castor action of the coulter 36 enables it to negotiate any rocks in the soil.

To ensure penetration of the digging share 32 to the required working depth, a number of weights 38 are mounted on the frame 11 above the digging share 32. To control the working depth of the share 32, a pair of ground wheels 39 are mounted on axles 40 carried on staunchions 41. The staunchions 41 are provided with a number of bolt holes 42 to enable the distance between the frame 11 and the wheels 39 to be adjusted.

In a modified form of this embodiment, the weights 38 are deleted and the hydraulic rams 23 are replaced by double acting hydraulic rams. By controlling the extension or retraction of these rams, the working depth of the digging share 32 can be controlled. As the rams are extended, the digging share 32 will be forced down to the required working depth.

By varying the length of the top link 18 of the tractor three-point linkage, the main frame 11 will be effectively rotated about an axis passing through the pins 20 engaging the lifting links and the angle of attack of the digging share 32 may be adjusted to suit the soil and crop conditions. For example, if the length of the top link 18 is increased, the main frame will be rotated clockwise about the axis passing through the pins 20, and the angle of attack of the digging share will be reduced.

Turning to the second embodiment illus trated in Figure 3 and 4, the harvester 50 has its main frame 51 mounted on a tractor 52 (shown in dashed lines). The tractor has an extended axle 53.

The main frame has a pair of side rails 54a, 54b and a central rail 55.

The central rail 55 and the side rails 54a are joined by an end rail 56. The forward ends of the side rail 54b and the central rail 55 each have vertical rails 57, 57a, the upper ends of which are connected by cross rails 58, 58a.

The rear ends of the side rails 54 and the central rail 55 are joined by a full-width end rail 59.

A vertical plate 60 is mounted adjacent the rear ends of the side rail 54b and the central rail 55. A sub-frame 61 is pivotally mounted on the vertical plates 60 for rotational movement relative to the main frame 51. The slat-type lifting elevator 62, the digging share 63, side plates 64 and braces 65 are mounted on the sub-frame 61 in a similar manner to the embodiment described with reference to Figures 1 and 2.

Suitable driving means (not shown) are provided to drive the elevator 62.

A hydraulic ram 66, mounted on the cross rail 58 and engaging a cross beam 67 on the sub-frame, is connected to the hydraulic system of the tractor. By adjusting the extension of the hydraulic ram, the digging share 63 is set and maintained at the required working depth. A rotary pick assembly 68 is mounted on the sub-frame 61 forward of the digging share 63 via vertical plates 69 carrying bearings 70. A shaft 71, driven by suitable means (not shown) is supported in the bearings 70. A plurality of picks 72 are spaced along and around the shaft 71. Each pick 72 has a leg extending radially from the shaft, and a foot extending tangentially forward from the fee end of the leg.

A pair of coulters 73 are mounted on the front of the sub-frame 61 in the manner described above with reference to Figures 1 and 2.

A number of fixed tines 74 are also mounted on the front of the sub-frame 61, between the coulters 73, to assist in breaking up the soil and cutting any roots they engage into short pieces.

A transverse elevator 75 is provided rearwardly of the lifting elevator 62, with an end shroud 76, to transfer cut root and soil from the lifting elevator 62 to a rotary sieve 77, where the harvested root is cleaned. A pivotably-mounted elevator 78 transfers the cleaned root from the rotary sieve 77 to a suitable transport trailer (not shown) or discharges the cleaned root in a row on top of the soil for later collection.

The embodiment illustrated in Figure 5 is a modified form of the embodiment of Figures 3 and 4 where the harvester is provided as a trailed implement supported on wheels 80 which carry the main frame 81.

The main frame 81 is provided with a towbar 82 which is connected to the drawbar 83 of a tractor 84. The sub-frame 85 is pivotally mounted on the main frame 81 and carries the lifting elevator 86, digging share 87, coulters 88, fixed tines 89 and rotary pick assembly 90 in the manner described with reference to Figures 3 and 4.

The working depth of the digging share 87 is set and controlled by a hydraulic ram connected between the main frame 81 and sub-frame 85 as previously described with reference to Figures 3 and 4.

The root lifted by the lifting elevator 86 is fed directly into the rotary sieve 91 which has its axis of rotation along the length of the harvester.

The cleaned root from the rotary sieve 91 is passed to a fixed unloading elevator 92 which transports the cleaned root to a transport trailer (not shown) or deposits the cleaned root in a row on the ground for later collection.

In the embodiments described, the combination of the means to force the digging share to the required working depth e.g.

weights, hydraulic ram between the main frame and sub-frame), the means for controlling the depth (e.g. the depth control wheels) and the relatively small angle of attack of the digging share ensures that the digger or harvester of the present invention will be capable of digging up the root crops.

The digging share can be set and maintained at the required working depth and the amount of drag on the tractor will be minimized as only a low angle of attack of the digging share is used.

WHAT WE CLAIM IS: 1. A mechanical digger or harvester for root crops including: a frame; ground engaging wheels supporting the frame at at least one selected height above the ground; a digging share mounted on the frame; penetration means for forcing the digging share into the ground to a working depth; depth control means for controlling the penetration of the digging share into the ground to the working depth, wherein: the angle of attack of the share at the working depth is maintained at substantially zero.

2. A digger or harvester as claimed in Claim 1 wherein the angle of attack is selectively variable by raising or lowering the frame relative to the ground.

3. A digger or harvester as claimed in Claim 1 wherein the height of the frame above the ground is fixed to provide the share with an angle of attack of substantially zero.

4. A digger or harvester as claimed in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. trated in Figure 3 and 4, the harvester 50 has its main frame 51 mounted on a tractor 52 (shown in dashed lines). The tractor has an extended axle 53. The main frame has a pair of side rails 54a, 54b and a central rail 55. The central rail 55 and the side rails 54a are joined by an end rail 56. The forward ends of the side rail 54b and the central rail 55 each have vertical rails 57, 57a, the upper ends of which are connected by cross rails 58, 58a. The rear ends of the side rails 54 and the central rail 55 are joined by a full-width end rail 59. A vertical plate 60 is mounted adjacent the rear ends of the side rail 54b and the central rail 55. A sub-frame 61 is pivotally mounted on the vertical plates 60 for rotational movement relative to the main frame 51. The slat-type lifting elevator 62, the digging share 63, side plates 64 and braces 65 are mounted on the sub-frame 61 in a similar manner to the embodiment described with reference to Figures 1 and 2. Suitable driving means (not shown) are provided to drive the elevator 62. A hydraulic ram 66, mounted on the cross rail 58 and engaging a cross beam 67 on the sub-frame, is connected to the hydraulic system of the tractor. By adjusting the extension of the hydraulic ram, the digging share 63 is set and maintained at the required working depth. A rotary pick assembly 68 is mounted on the sub-frame 61 forward of the digging share 63 via vertical plates 69 carrying bearings 70. A shaft 71, driven by suitable means (not shown) is supported in the bearings 70. A plurality of picks 72 are spaced along and around the shaft 71. Each pick 72 has a leg extending radially from the shaft, and a foot extending tangentially forward from the fee end of the leg. A pair of coulters 73 are mounted on the front of the sub-frame 61 in the manner described above with reference to Figures 1 and 2. A number of fixed tines 74 are also mounted on the front of the sub-frame 61, between the coulters 73, to assist in breaking up the soil and cutting any roots they engage into short pieces. A transverse elevator 75 is provided rearwardly of the lifting elevator 62, with an end shroud 76, to transfer cut root and soil from the lifting elevator 62 to a rotary sieve 77, where the harvested root is cleaned. A pivotably-mounted elevator 78 transfers the cleaned root from the rotary sieve 77 to a suitable transport trailer (not shown) or discharges the cleaned root in a row on top of the soil for later collection. The embodiment illustrated in Figure 5 is a modified form of the embodiment of Figures 3 and 4 where the harvester is provided as a trailed implement supported on wheels 80 which carry the main frame 81. The main frame 81 is provided with a towbar 82 which is connected to the drawbar 83 of a tractor 84. The sub-frame 85 is pivotally mounted on the main frame 81 and carries the lifting elevator 86, digging share 87, coulters 88, fixed tines 89 and rotary pick assembly 90 in the manner described with reference to Figures 3 and 4. The working depth of the digging share 87 is set and controlled by a hydraulic ram connected between the main frame 81 and sub-frame 85 as previously described with reference to Figures 3 and 4. The root lifted by the lifting elevator 86 is fed directly into the rotary sieve 91 which has its axis of rotation along the length of the harvester. The cleaned root from the rotary sieve 91 is passed to a fixed unloading elevator 92 which transports the cleaned root to a transport trailer (not shown) or deposits the cleaned root in a row on the ground for later collection. In the embodiments described, the combination of the means to force the digging share to the required working depth e.g. weights, hydraulic ram between the main frame and sub-frame), the means for controlling the depth (e.g. the depth control wheels) and the relatively small angle of attack of the digging share ensures that the digger or harvester of the present invention will be capable of digging up the root crops. The digging share can be set and maintained at the required working depth and the amount of drag on the tractor will be minimized as only a low angle of attack of the digging share is used. WHAT WE CLAIM IS:

1. A mechanical digger or harvester for root crops including: a frame; ground engaging wheels supporting the frame at at least one selected height above the ground; a digging share mounted on the frame; penetration means for forcing the digging share into the ground to a working depth; depth control means for controlling the penetration of the digging share into the ground to the working depth, wherein: the angle of attack of the share at the working depth is maintained at substantially zero.

4. A digger or harvester as claimed in

any one of Claims 1-3 wherein the working depth is between 30 and 40 cm.

5. A digger or harvester as claimed in Claim 1 wherein: the digging share is mounted on a sub-frame pivotally mounted on the frame.

6. A digger or harvester as claimed in any one of Claims 1-5 wherein: the longitudinal axis of the digging share is transverse to the longitudinal axis of the frame.

7. A digger or harvester as claimed in any one of the preceding claims wherein: the longitudinal axis of the digging share is substantially horizontal.

8. A digger or harvester as claimed in any one of the preceding claims wherein: the penetration means includes weights mounted on the frame and positioned substantially above the digging share.

9. A digger or harvester as claimed in Claim 5 or any one of Claims 6 to 8 when appendant to claim 5 wherein: the penetration means includes a hydraulic ram acting between the frame and the sub-frame.

10. A digger or harvester as claimed in any one of Claims 1 to 7 wherein: the frame is adapted to be mounted on the three-point linkage of a tractor, the linkage comprising a top link and two lifting links; and the penetration means includes a hydraulic ram acting between the tractor and at least one of the said lifting links.

11. A digger or harvester as claimed in Claim 10 wherein: the hydraulic ram is double-action ram and incorporates the depth control means.

12. A digger or harvester as claimed in any of Claims 1 to 11 wherein: the depth control means is a ground engaging wheel mounted on the frame.

13. A digger or harvester as claimed in Claim 12 wherein: the wheel is mounted for adjustment in the vertical direction.

14. A digger or harvester as claimed in any one of the preceding claims and further including: coulters or discs mounted on the frame forward of the digging share.

15. A digger or harvester as claimed in Claim 14 wherein: the coulters or discs penetrate the ground to substantially the same depth as the digging share.

16. A digger or harvester as claimed in any one of the preceding claims and further including: fixed times mounted on the frame forwardly of the share.

17. A digger or harvester as claimed in any one of the preceding claims and further including: a rotary pick assembly mounted on the frame forwardly of the digging share.

18. A digger or harvester as claimed in Claim 17 wherein the rotary pick assembly includes: at least one mounting block on the frame; a driven shaft rotatably mounted in bearings in said block; and spaced digging picks extending substantially radially from the shaft.

19. A digger or harvester as claimed in Claim 18 wherein: the digging picks include tangential extensions at the free ends of the picks.

20. A digger or harvester as claimed in any one of Claims 1 to 9 or Claims 12 to 19 wherein: the frame is adapted to be mounted on the three-point linkage of a tractor.

21. A digger or harvester as claimed in Claim 20 wherein: the angle of attack of the digging share is adjusted by varying the length of the top link of the tractor three-point linkage.

22. A digger or harvester as claimed in any one of Claims 1 to 9 and Claims 12 to 19 wherein: the frame is mounted on its own ground engaging wheels.

23. A digger or harvester as claimed in any one of Claims 1 to 9 or Claims 12 to 19 wherein: the frame is integral with the chassis of a self-propelled wheeled vehicle.

24. A digger or harvester as claimed in any one of the preceding claims and further including: an elevator mounted on the frame behind the digging share.

25. A digger or harvester as claimed in Claim 24 and furthering including: a sieve to clean the dug root.

26. A mechanical digger or harvester for root crops substantially as hereinbefore described with reference to Figures 1 and 2, Figures 3 and 4, or Figure 5.