GB1601478A

GB1601478A - Root harvesters

Info

Publication number: GB1601478A
Application number: GB4356077A
Authority: GB
Original assignee: National Research Development Corp UK; National Research Development Corp of India
Current assignee: National Research Development Corp UK; National Research Development Corp of India
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-10-28

Description

(54) IMPROVEMENTS IN AND RELATING TO ROOT HARVESTERS (71) We, NATIONAL RESEARCH DEVELOPMENT CORPORATION of 66 74 Victoria Street, London S.W.1., a British Corporation, established by Statute, 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: The present invention relates to the harvesting of root crops and has particular, but not exclusive, application to harvesting potatoes and other root crops grown in ridges In particular, the invention provides an improved share assembly and a root crop harvester (as hereinafter defined) including such an assembly.

Potato diggers comprise a share adapted to be drawn longitudinally along a ridge in which potatoes are growing to progressively break up and lift the ridge to deposit the material of the ridge on a conveyor. The conveyor conveys the material from the share.

Usually, the material is returned to the ground so that the potatoes can be hand picked or otherwise separated from the soil and other material of the ridge, for example haulm and weed. Alternatively, in more sophisticated harvesters, the conveyor conveys the material of the ridge for further treatment on the harvester, particularly separation of potatoes from some at least of the soil and other materials.

As used hereinafter, the term "harvester" will include both diggers and machines including diggers which further handle or treat the dug crop.

In the majority of potato harvesters presently in use the share is an inclined blade having a flat profile with a pointed leading edge. It is also known to form the blade of two or more segments each of which are individually pointed in order to assist passage of haulm and weed over the share.

Occasionally, the share is trough-shaped to make a curved cut in the ridge bottom instead of a vee or serrate shaped cut formed by the flat profile blade. In order to direct ridge material onto the conveyor, side plates are provided adjacent the share. The side plates can be flat or curved towards the share.

A build up of haulm or weed at the leading edge of the share can be prevented by the provision at said edge of a torpedo-shaped finger or a rotatable disc, which may have a plain or scalloped cutting edge. The conveyor usually is an endless belt or web arranged so that the material-receiving portion of the conveyor path is substantially parallel with the plane of the share. The gap between the upper end of the share and said portion of the conveyor can be bridged by fingers in order to reduce the risk of jamming.

Conventional potato harvesters having the kind share described above are capable of operating in a wide range of soil conditions but are not entirely satisfactory. In particular, the major difficulties encountered with such harvesters are the failure of their share to scour properly, the collection of haulm and weed round fixed parts of the share assembly, and, where rotating side discs are provided, jamming of those discs.

Concerning the failure to scour properly, the movement of soil along flat shares is dependent inter alia on the angle of tilt of the share and the length of the share from its leading to its trailing edge. Generally, soil will fail to move along a flat share tilted at an angle of greater than about 240 to the horizontal or if the length of the share exceeds about 475 mm. Typically the flat shoe of a potato harvester is tilted at an angle of 220 to the horizontaL Thus, even a modest downhill slope can lead to unsatisfactory scouring and thus to a build up of soil on the share. As a result, there can occur a significant loss of potatoes through spillage from the share and even blockage of the share.

The collection of haulm and weed round fixed parts of the share assembly is due to so-called "hair-pinning" by which a length of haulm or weed struck by a part of the harvester will bend so that the respective ends are located on different sides of the part and thereby the length is trapped leading to a build-up of haulm or weed which reduces the effidency of the harvester. In this manner, haulm or weed is built up particularly on the leading edge of the share, the junction of the share and side plates and the hubs of rotating side discs.

When rotating side discs are provided they are susceptible to jamming. In particular, if the discs are not penetrating deeply enough or if the harvester is not centrally disposed to the ridge or if haulm or weed build up around the hubs the discs will cease to rotate. If the discs are not rotating, the intake to the harvester rapidly becomes blocked.

Various modifications have been adapted in an attempt to overcome the problems encountered with the use of flat shares in potato harvesters. In particular, vibrating side plates have been provided to extend rearwardly from the share to the conveyor in order to improve the flow of material into the harvester. Further side discs have been provided with a ratchet drive in order to reduce the risk of jamming of the discs. Whilst these modification have improved the performance of the potato harvester having flat shares, they have not resulted in an entirely satisfactory harvester in that some at least of the difficulties referred to above remain.

In view of the inherent disadvantages of flat shares, a satisfactory alternative share arrangement has been sought for many years.

However, only two of the alternatives proposed to date have had any significant com- mercial success and, as reported previously, the majority of potato harvesters still employ a flat share. A first of said two alternatives is the use of a vbirating share and has been known since at least 1953 (see German Patent No. 3322 published 17th August 1953). The construction and operation of vibrating shares will not be described because they are not directly relevant to the present invention.

However, it should be noted that a vibrating share is still susceptible to blockage by "hairpinning" by haulm and weed and is liable to increase the cutting of tubers during harvesting. The second of the two alternatives is the use of disc shares and is the most relevant prior art to the present invention.

Accordingly, the construction and operation of disc share harvesters will be described.

It has been known for several years that the flat share of a potato harvester could be replaced by a rotating disc. In a double-row potato harvester manufactured in the German Democratic Republic, the share is constituted by a pair of power driven rotatable discs aligned with respective rows. These discs are tilted rearwardly upwards (relative to the direction of movement of the harvester) and are also tilted slightly in the lateral direction so that the discs converge towards each other to form a shallow vee-shaped cut in the ridge.

The precise angles of rearward and lateral cut are unknown but it is believed that the angle of rearward tilt is about 220 and the angle of lateral tilt is merely a few degrees.

Originally the discs were dished with their convex surfaces lowermost but such dished discs have now been replaced by centrally dished discs having a flat rim.

A single-row harvester has been proposed in which the driven discs are tilted rearwardly at 220 and laterally at 250, to provide an included angle of 1300 (see R. J.

Ofield, J. Agric. Engng. Res. 9(1) 298, 1964).

Two versions were proposed. In the first version, the gap between the discs is bridged by a small flat share, whilst in the second version the discs were closer together and no central share was required. We have satisfactorily used for four seasons a single row harvester similar to the said second variation but in which the lateral tilt was 57.50 to the horizontal.

Driven dished or flat disc shares of the kind described above are much less liable to choking by a build up of haulm and weed than conventional flat share harvesters. Moreover, there is a substantial reduction in force required to move said disc shares through the soil than for conventional flat shares of comparable size.

It has also been proposed to use inclined freely-rotatable disc shares of dished shape in which the discs are rotated by engagement with the soil. One embodiment of such ground-driven disc shares (see J. Hawkins, J.

Agric. Engng Res. (2) 1 1957) has been incorporated in a Massey Ferguson potato harvester. Said embodiment was of a construction similar to a large disc plough and operated on only a single ridge. In another embodiment, a four-row harvester was provided with ground-driven discs tilted rearwardly at 56 to 600 to the horizontal and laterally at 450 (see Razmislovic et al, Sovershenteev Selkhoz Techniki (25) 3-11 Minsk 1973).

Build up of soil on disc shares is conventionally removed by the location of a fixed cleaning blade spaced from the disc by a small clearance in order to scrape material from the disc.

It has now been found that the performance of potato harvester, especially two and other multiple row harvesters, can be improved by using a power driven rotating disc to clean material from the disc share. It will be appreciated that the advantages of said cleaning discs are not restricted to potato harvesters but can be applied also to other root crop harvesters.

According to the present invention, there is provided a rotatably mounted disc share and a rotatably mounted cleaning member, which cleaning member is adapted to be power driven and is arranged to over-lap a portion only of the disc share whereby, in operation, the cleaning member sweeps material from the upper surface of the disc share.

There is also provided in accordance with the present invention a share assembly comprising a pair of rotatably mounted disc shares mounted to have the centres thereof spaced laterally apart and to be mutually downwardly convergent, each disc share having a rotatably mounted cleaning member which cleaning member is adapted to be power driven and is arranged to over-lap a portion only of the associated disc share whereby, in operation, the cleaning member sweeps material from the upper surface of the associated disc share.

Thus it is to be appreciated that in succeeding paragraphs setting out preferred features of the invention, references to the disc share or the cleaning member are to be construed as meaning the or each disc share and the or each cleaning member, as appropriate.

It is preferred that the disc share is adapted to be power driven and/or is dished and disposed with its convex surface lowermost. It is particularly preferred that the disc share is tilted laterally of the direction of intended translational movement of the share assembly by an angle of up to 200 from the horizontal; The present invention, provides also a harvester comprising a conveyor and a share assembly in accordance with the present invention arranged to deposit material on the conveyor.

Preferably, the angle at which the disc share is tilted laterally of the direction of intended translational movement is in the range 50 to 100 and especially 80. It is also much preferred that the disc share is tilted rearwardly upwards in the said direction of movement. Suitably, the rearward tilt is in the range 180 to 320 especially 200 to 280 and particularly 220 to 250, from the horizontal.

The disc share conveniently can be mounted on an axle for rotation therewith. The axle being, or being adapted to be, received in a bearing carried by a harvester frame or sub frame. The harvester frame is provided with wheels or other ground-engaging means, for example skids, facilitating translational movement of the frame over the soil. Usually, the axle extends upwardly from the disc and, if desired, the disc is also supported from below by, for example, an axle extension received in another bearing carried by the frame. When the disc is to be power driven the drive will usually be transmitted to the axle by, for example, a belt, chain or gear drive driven from a power take off from an engine providing motive power to the harvester or a vehicle towing the harvester.

It has been found that a convenient disc share diameter for harvesting potatoes from ridges of the dimensions (i.e. 14 to 20 inch width) and spacing (i.e. 28 to 36 inch spacings) conventionally employed in the United Kingdom is 0.75 to 1 m especially about 0.9 m. When the disc share is dished, the radius of curvature is conveniently 0.9 to 1.5 m especially about 1.1 m. The speed of rotation of discs of said dimensions suitably is 50 to 100 rpm, especially about 80 rmp.

The cleaning member suitably is a complete or segmented disc or other member having an axis of symmetry, e.g. a rimless wheel having multiple spokes. Preferably, the cleaning member substantially overlaps a sector of the disc share and is rotated in the same rotational sense as the disc share. When the disc share is dished, it is preferred that the cleaning member is also dished and inverted relative to the disc share. The radii of curvature of a dished disc share and dished cleaning member will usually be matched so that the clearance between the periphery of the cleaning member and the upper surface of the disc share is substantially constant. Suitably, the clearance between a cleaning member and associated disc share is about 6 mm.

When a disc share of about 0.9 m diameter and about 1 m radius of curvature is employed an inverted dished cleaning member of about 0.55 m diameter and about 0.5 m radius of curvature suitably is employed.

The cleaning member conveniently is mounted for rotation with an axle which is mounted in a bearing on the harvester frame or a sub frame. Usually, the axle will extend upwardly from the upper surface of the cleaning disc and will be driven by, for example, a belt, chain or gear drive from the aforementioned power take off.

In order to prevent too much soil being carried round on the cleaning member, it is desirable to fit a small static scraper.

The ratio of rotational speed of the cleaning member to the disc share preferably is within the range 0.9:1 to 1.5:1 especially 1.2: 1. Thus, when the disc share is rotating at about 80 rpm, the cleaning member is suitably rotating at about 95 rpm.

It is preferred that a harvester is accordance wtih the present invention has a mutually downwardly convergent pair of disc shares spaced laterally apart and having respective rotating cleaning members which cause the streams of material passing from the share assemblies onto the conveyor to merge.

The provision of a rotating cleaning member provides an effective manner of cleaning a disc share which is much less prone to clogging than a stationary cleaning blade.

Further the pattern of flow from the disc share and breaking of soil is improved using the rotary cleaning member compared with the cleaning blade. The rotary cleaning mem ber is particularly advantageous when the disc share is tilted laterally at a relatively small angle of, for example, about 80.

The use of a laterally tilted dished disc share facilitates satisfactory lifting and break up of the ridge at relatively low power output. The share is not prone to clogging by haulm and weed, has low spillage loss and is not affected appreciably by the slope on which the harvester is operating. The flow of soil over the disc produces distortion leading to gentle break up of the ridge. It appears that a driven dished disc share of this invention can be operated at significantly higher translational speeds and can lift the material of the ridge to a greater height than prior art shares.

The following is a description by way of example only and with reference to the accompanying drawings of a presently preferred embodiment of the invention. In the drawings: Figure 1 is a diagrammatic plan view of a potato harvester in accordance with the preferred embodiment; Figure 2 is a diagrammatic end view of the harvester of Figure 1 seen in the direction of arrow A of Figure 1; Figure 3 is a diagrammatic side view of the harvester of Figure 1 in the direction of arrow B of Figure 1.

Referring to the Figures, a two-row potato harvester comprises a pair of laterally spaced harvester share assemblies generally shown at I located towards the forward end of the harvester and a conveyor 2 for conveying material rearwardly from the share assemblies to be deposited at the rear of the harvester.

Each share assembly 1 comprises a dished disc share 3 secured to an axle 4 for rotation therewith. The axle extends co-axially from the concave surface of the share 3 and depends from a journal box 5 carried by a wheeled frame 6 of the harvester. The axle can be driven by any suitable means. For example, a pulley or sprocket wheel carried by the axle can be driven by a belt or chain respectively driven from the power take off of a vehicle towing the harvester. Alternatively, the axle can be driven by a hydraulic motor supplied with hydraulic fluid from a pump driven from the power take off.

The axle 4 extends through the disc share 3 to protrude from the base thereof in a terminal portion 4a of reduced diameter.

This portion 4a is received in a bearing carried by a support member 7 of the frame 6.

A dished cleaning disc 8 is carried by an axle 9 for rotation therewith. A scraper 8A is mounted on the frame adjacent the cleaning disc. The axle 9 extends co-axially from the convex surface of the cleaning disc and is supported and driven at its distal end in a journal box 10. Conveniently, the axle 9 will be driven in the same manner as axle 4.

Axle 4 is inclined both laterally and longitudinally relative to the frame 6 in order to tilt the disc share 3 rearwardly and laterally. The rearward tilt is 220 from the horizontal and the lateral tilt is 60 from the horizontal, the discs of the two share assemblies 1 being mutually convergent as shown in Figure 2. The axle 9 is also inclined longitudinally and transversely with respect to the frame 6 so that the cleaning disc 8 sweeps over approximately a sector of the disc share 3. The relative dimensions of the disc share 3 and cleaning disc 8 and the relative position of axle 9 to axle 4 are selected so that the periphery of disc 8 is substantially uniformly spaced from the concave surface of the disc share 3. Conveniently, the disc share 3 has a diameter of 0.91 m and a radius of curvature of 1.07 m, whilst the cleaning disc has a diameter of 0.56 m and a radius of curvature of 0.5 m. The respective drives to the axles 4 and 9 are arranged so that the ratio of rotational speed of axle 9 to axle 4 is 1.2:1.

The conveyor 2 is of conventional construction being formed of a plurality of transversely extending and longitudinally spaced webs connected together to form an endless web passing about appropriately located rollers. The web is driven, by for example, driving the rearmost roller from the power take off of the towing vehicle.

In use, the harvester is towed by a tractor or other vehicle over a field in which potatoes are growing in parallel ridges. The spacing between the centre of the disc shares 3 is substantially equal to the distance between -the ridges and the harvester is positioned so that each disc is moved along the centre line of one of a pair of adjacent ridges. The harvester is moved longitudinally of the ridges at a speed of up to 5 mph depending upon soil conditions. As the harvester progresses, the disc shares 3 cut into the ridges to a level below the potatoes therein. The ridges are lifted onto the disc shares and fall into the concave upper surface of those shares.

Simultaneously, rotation of the shares 3 convey the material in an arcuate path towards the conveyor 2. The shares of each assembly rotate in mutually opposite directions but each cleaning disc 8 rotates in the same sense as the share with which it is associated. The rotation of the cleaning disc sweeps material from the disc share 3 onto the conveyor 2 while simultaneously serving to assist breaking up of the material. The material deposited on the conveyor 2 is conveyed rearwardly and falls from the conveyor at the rear of the harvester to leave a trail of material behind the harvester. Potatoes can then readily be removed from the broken up soil.

It has been found that satisfactory performance is obtained by rotating the disc shares 3 at about 80 rpm, in which case the clean ing discs are rotated at about 95 rpm.

It will be appreciated that the invention is not restricted to the particular details described above but that numerous modifications and variations can be made without departing from the scope of the invention. In particular, the harvester could include means for separating potatoes from the other material of the ridge, in which case the conveyor 2 would convey the potatoes to a further treatment station on the harvester. Also, where required, there may be fitted shields, baffles and deflectors for guidance of crop and soil.

WHAT WE CLAIM IS:- 1. A share assembly comprising a rotatably mounted disc share and a rotatably mounted cleaning member, which cleaning member is adapted to be power driven and is arranged to overlap a portion only of the disc share whereby, in operation, the cleaning member sweeps material from the upper surface of the disc share.

2. A share assembly comprising a pair of rotatably mounted disc shares mounted to have the centres thereof spaced laterally apart and to be mutually downwardly convergent, each disc share having a rotatably mounted cleaning member which cleaning member is adapted to be power driven and is arranged to over-lap a portion only of the associated disc share whereby, in operation, the cleaning member sweeps material from the upper surface of the associated disc share.

3. An assembly according to Claim 1 or 2 in which the or each disc share is adapted to be power driven.

4. An assembly according to Claim 1, 2 or 3 in which the or each disc share is dished and disposed with its convex surface lowermost.

5. An assembly according to any of Claims 1 to 4 in which the or each disc share is tilted laterally of the direction of intended translational movement of the share assembly by an angle of up to 200 from the horizontal.

6. An assembly according to Claim 5 in which the angle at which the or each disc share is tilted laterally of the direction of intended translational movemnet is in the range 50 to 100.

7. An assembly according to Claim 6 in which the angle at which the or each disc share is tilted laterally of the direction of intended translational movement is about 80.

8. An assembly according to any preced ing claim in which the or each disc share is tilted rearwardly upwards in the direction of intended translational movement of the share assembly.

9. An - assembly according to Claim 8 in which the rearward tilt is in the range 180 to 320, from the horizontal.

10. An assembly according to Claim 19 in which the rearward tilt is in the range 200 to 280 from the horizontal.

11. An assembly according to Claim 10 in which the rearward tilt is in the range 22' to 250 from the horizontal.

12. An assembly according to any preceding daim in which the or each disc share diameter is in the range 0.75 to 1 m.

13. An assembly according to Claim 12 in which the or each disc share diameter is about 0.9 m.

14. An assembly according to Claim 4 or according to any of Claims 5 to 13 in so far as dependent upon Claim 4 in which the radius of curvature of the or each disc share is in the range 0.9 to 1.5 m.

15. An assembly according to Claim 14 in which the radius of curvature of the or each disc share is about 1.1 m.

16. An assembly according to Claim 14 or 15 in so far as dependent upon Claim 12 or Claim 13 including means for rotating the or each disc share at a speed of rotation in the range 50 to 100 rpm.

17. An assembly according to Claim 16 in which the said means for rotating the or each disc share is adapted to rotate the or each disc share at a speed of about 80 rpm.

18. An assembly according to any preceding claim in which the or each cleaning member comprises a disc.

19. An assembly according to any preceding claim in which the or each cleaning member substantially overlaps a sector of the associated disc share and is adapted to be rotated in the same rotational sense as the disc share.

20. An assembly according to Claim 4 or any of Claims 5 to 19 in so far as dependent upon Claim 4 in which the or each cleaning member is also dished and is inverted relative to the associated disc share.

21. An assembly according to Claim 20 in which the radii of curvature of the or each dished disc share and the or each dished cleaning member are matched, so that the clearance between the periphery of the cleaning member and the upper surface of the associated disc share is substantially constant.

22. An assembly according to Claim 21 in which the clearance between the or each cleaning member and associated disc share is about 6 mm.

23. An assembly according to Claim 21 or Claim 22 in so far as dependent upon Claim 13 and Claim 15 in which the or each inverted dished cleaning member has a diameter of about 0.5 m and has a radius of curvature of about 0.5 m.

24. An assembly according to any preceding claim arranged in such a manner that in operation the ratio of rotational speed of the or each cleaning member to the associated disc share is within the range 0.9:1 to 1.5:1.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ing discs are rotated at about 95 rpm. It will be appreciated that the invention is not restricted to the particular details described above but that numerous modifications and variations can be made without departing from the scope of the invention. In particular, the harvester could include means for separating potatoes from the other material of the ridge, in which case the conveyor 2 would convey the potatoes to a further treatment station on the harvester. Also, where required, there may be fitted shields, baffles and deflectors for guidance of crop and soil. WHAT WE CLAIM IS:-

1. A share assembly comprising a rotatably mounted disc share and a rotatably mounted cleaning member, which cleaning member is adapted to be power driven and is arranged to overlap a portion only of the disc share whereby, in operation, the cleaning member sweeps material from the upper surface of the disc share.

25. An assembly according to Claim 24

in which the said ratio of rotational speed of the or each cleaning member to the associated disc share is substantially 1.2:1.

26. A harvester comprising a frame for movement over the ground during harvesting of a crop and a share assembly according to any preceding claim coupled to or mounted on the harvester frame.

27. A harvester according to Claim 26 including a conveyor for conveying harvested crop, the share assembly being arranged to deposit material on the conveyor.

28. A harvester according to Claim 27 in so far as dependent upon Claim 2 in which the respective rotating cleaning members of the mutually downwardly convergent pair of disc shares cause the streams of material passing from the disc shares onto the conveyor to converge.

29. A harvester according to Claim 26, 27 or 28 in which the or each disc share is mounted on an axle for rotation therewith, the axle being received in a bearing carried by the harvester frame, or by a sub-frame mounted on or coupled thereto, the axle extending upwardly from the disc.

30. A harvester according to Claim 29 in which the or each disc share is also supported from below by an axle extension received in another bearing carried by the said frame or sub-frame.

31. A harvester according to any of Claims 26 to 30 in which the or each cleaning member is mounted for rotation with an axle which is mounted in a bearing on the harvester frame or a sub-frame mounted on or coupled thereto, the axle of the or each cleaning member extending upwardly from the upper surface of the cleaning member.

32. A share assembly substantially as hereinbefore described with the reference to the accompanying drawings.

33. A harvester substantially as hereinbefore described with reference to the accompanying drawings.