GB2071979A - Root-crop harvesting machines - Google Patents

Abstract

A root-crop havesting machine has lifter wheels 3 and an extractor wheel 4 having an openwork periphery, such as an array of spaced-apart parallel rods 8, located between the lifter wheels at a position to engage lifted roots carried upwardly by the lifter wheels. The extractor wheel is driven in a manner to dislodge and propel rearwardly crop roots carried into engagement with it. <IMAGE>

Description

SPECIFICATION Root-crop harvesting machines This invention concerns root-crop harvesting machines such as are used for harvesting sugar beet, chicory, carrots, parsnips, turnips, swedes, potatoes and the like and is especially concerned with root-crop harvesting machines of the kind that utilise harvesting elements comprising a pair of lifter wheels that are oppositely inclined to a vertical plane generally aligned with respect to their path of motion so as to penetrate the ground and, owing to the convergence of those wheel parts penetrating the ground, to engage the opposite sides of each crop root and to squeeze and lift this from the ground. In machines of this kind, one or both of the lifter wheels may be power-driven, for instance as disclosed in U.K. Patent No. 985272.

A problem experienced in the use of machines of this kind is that of achieving reliable transfer of the lifted roots from the lifter wheels to the transporting means that are provided for conveying the lifted roots to a discharge or storage point on the machine, these transporting means usually being arranged to accomplish some cleaning of the lifted roots.

When lifting a crop such as sugar-beet in light, dry soil conditions, the lifted roots consistently separate from the lifter wheels to fall behind the latter on to part of the transporting means. However, when the crop is being harvested from heavy or wet soil, release of the lifted roots becomes irregular and indeed the entire space between the lifter wheels may become choked with lifted roots and other matter: in either event, the transfer of lifted roots to the transporting means becomes irregular or inter rupted, leading to difficulties in the operation of the transporting means and any crop-cleaning arrange ments that such means incorporate.

Several expedients have been tried to promote regular and reliable transfer of the lifted roots from the lifter wheels to the transporting means. Thus flails or paddles of varying degrees of stiffness have been arranged to move between the lifter wheels in a path to strike and rearwardly impel the lifted roots, but such arrangements tend either to damage the lifted roots or to fail to dislodge them from between the lifter wheels when the machine is working in adverse crop-lifting conditions and the lifted roots are heavily contaminated with adherent mud.

Another expedient that has been tried with a measure of success isthe provision of a driven link web arranged between the lifter wheels in the upper part of the gap therebetween, this extending rearwardly and somewhat upwardly and being so driven that its lower run moves rearwardly with respect to the direction of motion of the machine.Lifted roots that do not release from between the lifter wheels before being carried into contact with the lower run of this link web are thus forced into contact with the latter and, by reason of the orientation and motion of this lower run, are drawn out from between the lifter wheels with a force determined by the force with which the roots are pressed against the said lower run: as this latter force is related to the degree of adhesion of lifted root to the lifter wheels, the arrangement provides an extracting force that is related to the adhesion of a lifted root to the lifter wheels and thus, generally, sufficient only to free an adhering root, while not applying sufficient force to damage the root.

In practical operation of root-crop harvesting machines, crop roots are usually lifted along with a proportion of stones of varying sizes. The link web arrangement described above serves also to free larged jammed stones from between the lifter wheels in much the same manner as it extracts adherent crop roots. Smaller stones, however, often pass between the links of the lower run of the link web and enter the space between the two runs of this. While such stones usually again fall through the lower run before this has reached the reversing shaft and sprocket assembly at the rear end of the web, sometimes such stones become carried into the region of this reversing shaft and sprocket assembly and become jammed between the web and the assembly.This can damage the web and/or the assembly and can also halt the movement of the web whilst imposing severe loads on to the mechanism for driving it.

In accordance with the present invention a rootcrop harvesting machine of the kind having lifter wheels as above discussed is characterised by an extractor wheel having an openwork periphery at least the lower portion of which is located between the lifter wheels in a position to engage lifted crop roots being carried upwardly by the lifting wheels, said extractor wheel being adapted to be so rotated that its lower periphery moves rearwardly with respect to the direction of motion of the machine so as to impel rearwardly crop roots and other material lifted by the lifter wheels into engagement with the extractor wheel.

The openwork nature of the periphery of the extractor wheel renders the latter self-cleaning in the same manner as a link web: that is to say mud, soil and small stones may pass through the wheel periphery to be discharged from the interior of the wheel either laterally or by re-passing through the openwork periphery.

The extractor wheel diameter is preferably so chosen as to provide for its lower peripheral portion to extend between the lifter wheels from a position near the intersection of the axes thereof to beyond the periphery of the lifter wheels. In general this requires the extractor wheel to have a diameter not less than about half that of the lifter wheels. It will be understood that the larger the diameter of the extractor wheel the less curved will be the peripheral portion that effects the extraction of lifted roots and other material from between the lifter wheels and the better the approximation of this extractor wheel peripheral portion to the configuration of the lower run of the link web arrangement of the prior art.

However, space considerations and other factors will usually place a limit on the maximum diameter that may be chosen for the extractor wheel to be fitted to a particular machine.

The extractor wheel may have any suitable construction. For instance it may comprise a central disc or spoked hub carrying openwork rim flanges, or it may be of drum-like form with end discs or spoked hubs carrying an openwork peripheral structure therebetween.

The openwork peripheral structure may for instance be fabricated as apertured, e.g. pierced, sheet or as a grid or mesh. In preferred embodiments the openwork structure comprises an array of spacedapart rods parallel to the wheel axis and welded or otherwise secured to end rings that in turn are connected by spokes or equivalent to a hub structure. In embodiments in which the rods are of a significant length they may be braced by being welded or otherwise secured at one or more positions between their ends to respective bracing rings that may also be connected to the hub structure by spokes or equivaient means.

The extractor wheel may also have peripheral protrusions at intervals around its circumference to assist in dislodging particulariy jammed roots or stones lodged between the lifter wheels. In an embodiment in which the extractor wheel periphery -comprises spaced-apart parallel rods, certain of these, for instance three at 1200 intervals around the wheel, may carry protrusions in the form of plates or strakes welded to the rods in question.

The extractor wheel that characterises the invention may be applied to any root-crop harvesting machine of the kind having lifter wheels as discussed, whether this be of the self-propelled or trailed type.

The extractor wheel is preferably arranged for adjustment of its position with respect to the lifter wheels so that its lower peripheral portion may be set, relative to the axes and peripheries of the lifter wheels, in a position appropriate to a particular crop being lifted and to the harvesting conditions so as to achieve reliable extraction of lifted crop and other material from between the lifter wheels under those conditions.

Any suitable means may be provided for driving the extractor wheel in the required direction and at an appropriate peripheral velocity. In this connection the driving arrangements may provide for variation of the extractor wheel peripheral velocity to suit particular crop and harvesting conditions. In general the extractor wheel will be driven at such a speed as to provide a peripheral velocity similar to the forward velocity of the harvesting machine, whereby the rearwardly moving lower peripheral portion of the extractor wheel will be approximately stationary relative to the ground and to a root being lifted by the lifter wheel, and thereby avoid applying unnecessary shearing loads on a lifted root.

The accompanying drawings illustrate the relevant components of a root-crop harvesting machine embodying the invention. In these drawings: Figure lisa pictorial diagram ofthe lifter wheels and extractor wheel of an embodiment, showing the relative positions of these components; Figure 2 is an exploded pictorial view of the extractor wheels and their mounting arrangements for a three-row sugar-beet harvesting machine; Figure 3 shows a detail of the mounting arrangement of Figure 2; Figure 4 is a plan view of the assembly of Figure 3; Figures 5 and 6 are sections at lines 5-5 and 6-6, respectively, of Figure 4; Figure 7shows a central disc for a preferred extractor wheel; and Figure 8 is a scrap section illustrating the peripheral protrusions of the preferred extractor wheel.

Figure 1 illustrates diagrammatically the relevant components of a root-crop harvesting machine, such as a sugar-beet harvesting machine, embodying the invention. The drawing shows chassis members 1 and 2 that support the mountings for a pair of lifter wheels 3 that are arranged for rotation about axes oppositely inclined to a central vertical plane that in operation of the machine is generally aligned with the direction of motion of the machine along a row of crop roots to be lifted. The disposition of the lifter wheels axes is such that the wheels 3 converge together downwardly and rearwardly with regard to the direction of motion of the machine, the regions of closest approach of the lifter wheels 3 being somewhat to the rear of their lowermost regions.

The wheels 3 may be arranged for free rotation about their axes or one or both of the wheels may be arranged to be power driven, typically at a peripheral speed approximately corresponding with the forward speed of the harvesting machine relative to the ground when in operation.

In accordance with the invention, an extractor wheel 4 is arranged with its axis disposed perpendiocular to the notional vertical plane between the lifter wheels 3, the extractor wheel 4 being arranged symmetrically with respect to the lifter wheels 3 with the lower portion of its periphery 5 disposed between the lifter wheels in a position to be engaged by lifted crop roots being carried upwardly by the lifter wheels 3.The extractor wheel 4 is mounted upon an axis 6 adapted to be power driven so that the lower periphery of the wheel 4 moves rearwardly - this is, to the right as seen in Figure 1 - with respect to the direction of motion of the machine so that lifted crop roots brought into engagement with the periphery of the extractor wheel 4 will be impelled rearwardly by the latter, out of engagement with the lifter wheels 3, to strike a transverse barrier (not shown) and then to fall on to a transporting device such as a conveyor web (not shown).

As illustrated, the periphery 5 of the extractor wheel 4 is of openwork configuration. Figure 1 shows diagrammatically that the wheel 4 is of drum-like form, comprising end rings 7 spanned by an array of spaced-apart parallel rods 8 that are supported mid-way along their lengths by engagement with a ring 9 carried by spokes radiating from a hub on the axle 9. The preferred configuration for the extractor wheel 4 is further illustrated and described with respect to Figures 7 and 8.

Figures 2 to 6 illustrate a typical arrangement for mounting a set of extractor wheels 4 for cooperation with the three pairs of lifter wheels 3 (not shown) of a sugar-beet harvester intended to work on three crop rows at a time. As shown in these Figures, the three extractor wheels 4 are each keyed to a common axle 6 the ends of which are carried in bearings 10 fixed to mounting brackets 11 that are pivotally mounted by pivot bolts 12 on support plates 13 carried by longitudinal chassis members 14 braced by cross members 15. The mounting brackets 11 each have an arcuate slot 16 centered on the pivot bolt 12 and that receives a clamp bolt 17 by means of which an adjusted position of the mounting bracket 11 relative to its support plate 13 may be reliably maintained.

Each mounting bracket 11 has lugs 18 carrying adjustment screws 19 adapted to engage a stop bracket 20 fixed to the adjacent chassis member 14 so that by differential adjustment of the screws 19 with the clamp bolt 17 released the mounting bracket may be adjusted in position relatively to its support plate 13, thereby to adjust the vertical position of the adjacent end of the axle 6 carrying the extractor wheels 4 in order to enable a required positioning of the extractor wheels 4, relative to the lifter wheels, to be obtained.

Near one end, the axle 6 also carries a sprocket 21 for a driving chain 22 that extends to drive sprocket 23 on a drive shaft 24 suitably driven as by a prime -mover on the harvesting machine or from a power take-off coupling in the case of an unpowered, trailed, harvesting machine.

The lower run of the chain is engaged by a tensioning slipper 25 of a suitable tensioning device 26 that maintains an appropriate tension in the chain 22.

The preferred construction of the extractor wheels 4 is illustrated in Figures 2,7 and 8. As appears from these figures, each extractor wheel 4 consists of an apertured central disc 30 arranged for bolting to a hub 31 having a split clamp 32 by which the hub may be clamped on to the axle 6 and thus secure the extractor wheel 4 thereto. The hub 31 has a keyway engaging a key that also engages a co-operating keyway on the axle 6.

Each extractor wheel 4 further comprises two end rings 33 and a set of spaced-apart rods 34 that extend parallel with the axis of the wheel and are welded at their ends to the end rings 33.

In the embodiment illustrated there are twentyone such rods 34 equiangularly spaced-apart around the circumference of the wheel, each being received in a slot in the periphery of the central disc 30, to which the rod is also welded.

Every seventh rod 34 carries a radially projecting plate or stake 35 welded thereto and protruding outwardly from the wheel 4 at 1200 intervals around the circumference thereof. These plates or strakes 35 are welded to their adjoining rods 34 and to the disc 30 and end ring 33.

In the illustrated embodiment the overall diameter of the extractor wheel 4 is about 500 mm and the rods 34 have a diameter of about 12 mm. The plates or strakes 35 have a thickness of about 6 mm, and a width - that is a radial extent - about 25 mm, so as to project by this distance beyond the general periphery of the wheel 4.

Extractor wheels of these dimensions are suitable for use with lifter wheels 3 having a range of size but would typically be fitted to a harvesting machine having lifter wheels of about 720 mm diameter.

The plates or strakes 35 serve, as described, to dislodge jammed or firmly adherent crop roots etc.

from the lifter wheels. Such jamming or adhesion occurs predominantly when harvesting a crop in heavy land and for operation in light land the plates or strakes are not usually required. For this reason, harvesting machines that may have to work in both heavy and light land may be provided with detachable plates or strakes, similar in form to those described but having U-clamps for detachable fitment to the rods 34 when required, and gussets to engage the rim of the disc 30 to maintain the radial attitude of the plates or strakes.

Claims (10)

1. A root-crop harvesting machine having harvesting elements comprising a pair of lifter wheels oppositely inclined to a vertical plane generally aligned with respect to the path of motion of said wheels in operation, characterised by an extractor wheel having an openwork periphery at least the lower portion of which is located between the lifter wheels in a position to engage lifted crop roots being carried upwardly by the lifter wheels, said extractor wheel being adapted to be so rotated that its lower periphery moves rearwardly with respect to the direction of motion of the machine so as to impel rearwardly crop roots and other material lifted by the lifter wheels into engagement with the extractor wheel.

2. A machine according to claim 1, in which the extractor wheel has a diameter such that its lower peripheral portion to extends between the lifter wheels from a position near the intersection of the axes thereof to beyond the periphery of the lifter wheels.

3. A machine according to claim 1 or 2, in which said extractor wheel is of drum-like form.

4. A machine according to claim 3, in which said extractor wheel comprises end discs supporting an array of spaced-apart rods parallel to the wheel axis.

5. A machine according to any one of claims 1 to 4, in which said extractor wheel has peripheral protrusions at intervals around its circumference.

6. A machine according to any one of claims 4 and 5, in which said protrusions comprise plates or strakes secured to certain of said rods.

7. A machine according to any preceding claim, in which the extractor wheel is arranged for adjustment of its position with respect to the lifter wheels.

8. A machine according to any preceding claim, including means for driving the extractor wheel to provide the same a peripheral velocity similar to the forward velocity of the harvesting machine when in operation.

9. A harvesting machine according to any preceding claim and constructed and arranged substantially as described with reference to the accompanying drawings.

10. Every novel feature and every novel combination of features disclosed herein.