POTATO HARVESTER

Abstract: A potato harvester comprises a coarse screen web conveyor (4), a digging device (1) upstream thereof, an elevator (7) located downstream of the coarse screen web conveyor (4), a haulm separating device and a stone and clod separating device (9), wherein the elevator (7) is formed by a double conveyor having an inner, rotatable, close-meshed web conveyor (13) and an outer de-vining conveyor (14) rotatable in the same direction and arranged in parallel to each other. In order to facilitate haulm separation, the de-vining conveyor (14) has transverse finger strips (15) extending away from the web conveyor (13) and runs closely over the web conveyor (13) along the elevating section of the elevator.

Description: Potato Harvester The present invention relates to a potato harvester comprising a coarse screen web conveyor, a digging device upstream thereof, an elevator located downstream of the coarse screen web conveyor, a haulm separating device and a stone and clod separating device, wherein the elevator is formed by a double conveyor having an inner, rotatable, close-meshed web conveyor and an outer de-vining conveyor rotatable in the same direction and arranged in parallel to each other. In known potato harvesters of this kind, fine screen conveyors, elevators and haulm- separators form separate units which are known in various forms. A recent potato harvester of this kind (see DE 35 29 464) is known in which the elevator is intended to perform a double function. The elevator is formed by a double conveyor which comprises a close-meshed web conveyor rotating on the inside and acting as the potato conveyor and a wide-meshed web conveyor (known as a "de-vining" conveyor) rotating in the same direction on the outside, parallel to the inner conveyor and having entrainers. However, this potato harvester has the following disadvantages: a. The potatoes adhering to the haulm, if they lie in front of the entrainers of the wide-meshed web conveyor, may not be separated from the haulm, because this area cannot be reached either from above or from beneath with stripping paddles, rollers or the like. These potatoes go to waste along with the haulm or, alternatively, the haulm is carried through with the potatoes. b. With heavy, moist soils, it is an advantage if the entrairdng haulm conveyor can be operated to move faster than the web conveyor, but that is not possible with the known construction because, the scraping edges of the entrainers are not sufficiently robust to provide adequate scraping. It is known to overcome these disadvantages (DE 195 24 145 Al) by providing a third conveyor in the elevating region. However, this results in high construction and repair costs, as well as an increased risk of clogging in rough field use. An object of the present invention is to provide a potato harvester without the above disadvantages and in which the elevator can carry out fine screening and also haulm separation at the same time. The invention provides a potato harvester as claimed in Claim 1. In the potato harvester according to the invention, the screening conveyor performs coarse screening, and the elevator, as well as lifting material, also performs residual screening and haulm separation. The invention will now be described with reference detail to embodiments shown by way of example in the accompanying drawings, wherein: Fig. 1 shows a simplified perspective view of a potato harvester according to the invention, Fig. 2 shows three disassembled partial views of the elevator of Fig. 1, Fig. 3 shows three disassembled partial views of the elevator of Fig. 1 provided with ties, Fig. 4 is a plan diagrammatic view of part of the de-vming conveyor but not showing the ties provided, Fig. 5 is a diagrammatic plan view of part of an alternative de-vining conveyor, Fig. 6 is a cUagrarnmatic plan view of a further alternative de-vining conveyor, and Fig. 7 is a diagrammatic side view stripping zone of the de-vining conveyor. In Fig. 1 a potato harvester comprises a digging device 1, which is formed by shares 2, a ridged or diabolo roller 3 arranged upstream of the shares 2, a coarse screening conveyor 4 arranged downstream of the digging device 1 and in the form of a continuous web conveyor driven by drive rollers 6 around deflecting rollers 5, a lifting conveyor or elevator 7 located immediately downstream of the coarse screening conveyor 4 and forming a fine screening and haulm separating device, an onward- conveying unit 8, and also a stone and clod separating device 9, which transfers potatoes separated from stones and clods via a sorting conveyor 10 to a hopper 11 , and conveys stones and clods via a trash conveyor 12 to a collecting container (not shown). The single-row potato harvester shown is pulled by a tractor and is itself driven via Cardan shafts and transmissions or hydraulic motors and may also be in the form of a multi-row harvester. Alternatively the harvester may be self-propelled. The elevator 7 consists of two conveyors, an inner meshed web conveyor 13 and an outer dehaulming or "de-vining" conveyor 14. The de-vining conveyor 14 runs close to and in parallel with the web conveyor belt 13 over the elevating section of the elevator 7. The conveyor 13 has transverse bars 13 attached to side belts 16, and the de-vining conveyor 14 has entraining finger strips 15 extending transversely of the direction of travel of the conveyor 14 and mounted on side belts 27. The lower end of the web conveyor 13 runs around deflecting rollers 17 and the upper end runs around drive rollers 18 driven by a shaft 19. The outer, de-vining conveyor 14 runs around deflecting rollers 20, closely over the inner web conveyor 13 and parallel thereto, and is driven by driving pulleys 21 mounted on a shaft 22. The elevator 7 operates as follows: The harvested crop partially screened of earth on the coarse-screening conveyor 4 is conveyed to the elevator 7. Here, the harvested crop passes through to the close-meshed web conveyor 13, the bars 16 of which have an approximate clearance width of 25 to 45 mm. The elevator 7 has to reach, over a short construction length, a height dependent on the downstream units, since it has a steep incline. Therefore, the web conveyor 13 is not able to lift material without assistance, and this is provided by the de-vining conveyor 14 with the entraining finger strips 15 mounted transversely of the direction of travel. The spacings between the finger strips 15 are about 150 to 300 mm. The fixed, or incrementally, or infinitely variable difference in rotational speed between web conveyor 13 and the de-vining conveyor 14 ensures that any residual earth is screened away. If the web conveyor 13 runs faster than the de-vining conveyor 14, the potatoes are given a rotating motion and residual screening is thereby achieved. In the case of heavy, moist earth, the de-vining conveyor 14 is made to run faster than the web conveyor 13. The lower or scraping edges of the finger strips 15 are reinforced by means of attachment bars 23 to ensure that adequate scraping that takes place. When the potatoes have been transferred from the web conveyor 13 to the unit 8, which then passes them on, the wide-meshed de-vining conveyor 14 passes through a stripping zone 24. Here the potatoes attached to the haulm are stripped by holding-down members or strippers 26 (see Fig. 7), which extend through the gaps between the fingers of the finger strips 15. The dangling potatoes attached to the haulm are stripped away by means of a driven, counter-rotating roller 25. As the de-vining conveyor 14 returns, the detached potato haulm drops away easily from the fingers of the finger strips 15. Various modification may be made to the above embodiment of the potato harvester. Thus, the finger strip 15 may be provided with rubber or plastics fingers or plates. As can be seen from Fig. 3, the de-vining conveyor 14 may be provided with ties 30 (eg wires, belts etc) extending between the finger strips 15 in the direction of travel. Preferably, the ties 30 may extend from the top of each finger strip 15 to the bottom or top of the adjacent downstream finger strip 15 so as to provide support for the fingers or plates of the finger strips 15. The ties 30 may be elastic to allow passage around the rollers 21 and 30 without deforming the finger strips 15. Alternatively or in addition, as may be seen from Figs. 2 and 7, the de-vining conveyor 14 may be provided with ties 29 (eg wires, belts etc) extending between the finger strips 15 in the direction of travel, preferably from the bottom of one finger strip to the bottom of the adjacent finger strip, to provide extra support for the haulm so as to prevent it falling through to the web conveyor 13. As can be seen from the embodiment of Fig. 5, no ties have been provided, but alternate finger strips 15 have been replaced by plain transverse bars 28, which may be covered with rubber or plastics material. In the embodiment shown in Fig. 6 the fingers of the finger strips 15 do not extend completely to both ends of each strip 15. A free portion 15 without fingers is provided at alternate ends of adjacent strips 15. Although the harvester shown in the Figures incorporates a "single-row" conveyor, the harvester could incorporate a double or multi-row conveyor. Thus, the width of the coarse screening conveyor 4 and the elevator 7 could be doubled or made even greater. Two, four or even more diabolo rollers 3 may be provided. In this case it may be necessary to move the hopper 11 to the rear of the harvester and extend the conveyors 10 and 12 rearwardly. Alternatively, the hopper 11 could be replaced by another container or even a further conveyor.

Claims: Claims: 1. A potato harvester comprising a coarse screen web conveyor (4), a digging device (1) upstream thereof, an elevator (7) located downstream of the coarse screen web conveyor (4), a haulm separating device and a stone and clod separating device (9), wherein the elevator (7) is formed by a double conveyor having an inner, rotatable, close-meshed web conveyor (13) and an outer de- vining conveyor (14) rotatable in the same direction and arranged in parallel to each other, characterised in that the de-vining conveyor (14) has transverse finger strips (15) extending away from the web conveyor (13) and runs closely over the web conveyor (13) along the elevating section of the elevator. 2. A potato harvester according to Claim 1, wherem the fmger strips (15) are provided with rubber or plastics fingers. 3. A potato harvester according to Claim 1, wherein the fmger strips (15) are provided with rubber or plastics plates. 4. A potato harvester according to any one of Claims 1 to 3, wherein one or more transverse bars (28) without entraining fingers or plates are provided between the entraining finger strips (15). 5. A potato harvester according to any one of Claims 1 to 4, wherein ties (30) extend in an inclined manner between the finger strips (15) in the direction of travel. 6. A potato harvester according to any one of Claims 1 to 4, wherein ties (29) extend between the lower region of the finger strip (15) in the direction of travel. 7. A potato harvester according to any one of Claims 1 to 6, wherein holding-down members or strippers (26) are provided to sweep through gaps between the fingers of the finger strips (15), thereby, in use, causing potatoes attached to haulm to be stripped off. 8. A potato harvester according to any one of Claims 1 to 7, wherein a driven, counter-rotating roller (25) is arranged beneath the de-vining conveyor (14), so that potatoes attached to haulm and dangling through the de-vining conveyor (14) are stripped away. 9. A potato harvester according to Claim 1 to 8, wherein the fingers of the finger strips (15) do not extend completely to the ends of each finger strip (15), a free portion without fingers being provided at alternate ends of adjacent finger strips (15). 10. A potato harvester according to any one of the preceding claims, wherein the coarse screen web conveyor (4) and the elevator (7) are of sufficient width to operate as a two or multi-row conveyor.

Inventors: WELP JOHANNES, WELP, JOHANNES
Applicants: PEARSON RICHARD LTD, WELP JOHANNES, RICHARD PEARSON LIMITED, WELP, JOHANNES
Application year: 1999
Main classification: A01D33
IPC codes: A01D17, A01D33