GB2276573A - Crop grader with device for removing crop lodged in conveyor mesh - Google Patents

Abstract

Apparatus for conveying and grading crop eg potatoes, comprises a flexible mesh conveyor 20 having a driven shaft 30 carrying resilient flap-like projections 32 mounted so as to contact the underside of the conveyor and remove crop lodged therein. The projections 32 rotate in the same direction to that of the forward travel of the conveyor and at a speed 250 - 400% faster. <IMAGE>

Description

METHOD AND APPARATUS FOR GRADING AND CONVEYING CROP OR THE LIKE This invention relates to a method and apparatus for grading and conveying crop or the like. An example of the use of the invention is in the grading and conveying of a harvested potato crop. The invention is also applicable to other crops and may be used in any situation where it is desired to grade and sort a crop by means of size. One application of the invention would be in a potato or like grader.

Crop grading apparatus of the type mentioned is used to select or grade a crop according to size. The harvested crop, such as potatoes, is conveyed by a grading module. The grading module generally comprises a flexible mesh and is in the form of a conveyor. The potatoes are either retained by the mesh and conveyed onwards or else passed through the mesh and are collected or conveyed separately. During such an operation the potatoes may partially pass through the mesh and become lodged therein. Any potatoes so retained will be caught between the mesh and the roller at the end of the conveyor and crushed, resulting in damage to the potato. This can result in significant economic losses.

Prior disclosures to which attention is drawn include GB 1,571,678 (Satake Engineering Company Limited), GB A-2 ,223 ,778 (Penta-Ocean Construction Company Limited), GB-A-2,074,902 (Litton Systems Inc), GB 1,562,737 (Gent), GB-A-2,035,140 (Ukrainsky Nauchno Issledovatelsky Institute), GB-A-2,045,113 (Secretary of State for Industry), GB 1,154,196 (Wehner), GB 811,255 (Bensemann) and GB 518, 539 -(Griffiths).

None of the above specifications provides any relevant teaching in relation to the removal of crop items which become lodged in a grading conveyor in a crop or like grading and conveying apparatus.

Accordingly, a need for improvements in this respect or generally have been identified.

According to the invention there is provided crop or the like conveying or grading apparatus and a method of conveying and grading crop or the like as identified in the accompanying claims.

In an embodiment of the invention there is provided crop or the like grading and conveying apparatus in which a driveable conveyor element is provided with a plurality of projections mounted adjacent said conveyor element and extending across the width thereof so as to contact the underside of said conveyor element to remove crop or the like lodged therein. In this way crop which has become lodged in the conveyor is dislodged and conveyed onwards.

Also in the embodiment, the projections are mounted on a shaft arranged to be rotated and driven in the direction of forward travel of the conveyor element and are constructed of a resilient material.

In this way the projections are provided with a simple means for giving them the necessary positive "lifting" action. This is accentuated by the speed of rotation of the shaft and thus the projections mounted thereon in relation to the speed of travel of the conveyor element.

Moreover, the provision of the projections in resilient form enables them to deflect and pass over that portion of the crop item lodged in the conveyor and projecting through to the underside of said conveyor and lift them so as to release them from the conveyor element, the projections then flick back into the straight condition. In addition, the flexible nature of the projections allow them to pass over any crop item too firmly lodged to be removed without causing damage to the projections.

In the embodiment, the projections are disposed concentrically about the axis of rotation of the shaft on which they are mounted. In this way a successive cleaning of the conveyor element is provided as it travels over the projections. The drive for the projections may be arranged to rotate them at from 250 to 400% greater than the speed of forward travel of the conveyor element.

Also in the embodiment, the projections have a flap-like form. The working attitude of the conveyor element and the shaft being such that the rotation of the shaft and the associated resilient projections results in a "beating" action of the latter on the underside of the conveyor element and that portion of the crop which projects through the conveyor element when the crop item is lodged therein.

The length of the projections and the resilient form thereof result in the projections bending as they move over the underside of the conveyor element in a trailing form so as to make non-aggressive contact with the underside of the conveyor element and any crop lodged therein. The flexing action of the resilient projections reduces damage occurring to the crop as a result of direct contact with the projections.

As regards the outward or radial extent of the projections from the shaft or other mounting, this is arranged in relation to the conveyor element so that the projections extend towards the underside of the conveyor element so as to be caused to bend, when rotated into contact therewith to effect a "beating" action.

In a further embodiment of the invention the projections make contact with the underside of the conveyor element during use and act to remove waste material which adheres to the conveyor element during use and assist in maintaining the sizing accuracy of the element.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which Fig 1 shows a plan view of a typical crop or the like conveying and grading apparatus of the type which would utilise the invention; Fig 2 shows a side elevation view of the apparatus of Fig 1; and Fig 3 shows a schematic side elevation view comprising the conveying and grading element and a portion of the axial length of the shaft including the associated projections.

As shown in the drawings, a typical crop conveying and grading apparatus 10 comprises a bulk hopper 12 to receive the bulk crop once harvested. A cleaner module 14 may be provided to clean the crop and facilitate the removal of stones and clods prior to grading. The waste material removed by the cleaner module 14 is removed by conveyor 16 located beneath the cleaner module 14. The crop is then conveyed onto a grader module 18. The grader module 18 comprises a flexible mesh in the form of a driveable grading conveyor 20 utilising four conveyor rollers 22, 24, 26, 28, as seen in Figs 2 and 3.

As seen in Fig 3, shaft 30 and associated projections 32 are located adjacent the roller 28 of the flexible mesh conveyor 20 so as to contact the underside of the grading conveyor 20. The shaft 30 is driveably mounted on the chassis of the apparatus.

Between the shaft 30 and the underside of the grading conveyor 20 is an otherwise occupied space 34 into which projections 32 extend.

Projections 32 are mounted onto a shaft 30 as shown in Fig 3 through riveting to the square section shaft 30. The shaft 30 is mounted in end bearings.

The direction of rotation of the shaft 30 and associated projections 32 is shown in Fig 3 and likewise the direction of forward travel of the grading conveyor 20 and thus the conveying direction for crop passing over the apparatus is indicated by arrow D in Fig 3. Projections 32 are in the form of flaps consisting of a resilient material such as natural or synthetic rubber or any other suitable polymer each extending across the full width of conveyor 20. Their general form is seen in Fig 3.

Projections 32 are disposed tangentially with respect to shaft 30.

The drive (not shown) for the shaft 30 is arranged to rotate the shaft 30 at a different speed to the forward speed of the grading conveyor 20 preferably in the range from 250 to 400% faster and, optimally, between 325 to 375% faster. By virtue of the differential in speed the projections 32 act on successive portions of the grading conveyor 20 so as to remove crop lodged therein efficiently. The axis of the shaft 30 extends laterally across the width of the grading conveyor 20.

In use, crop material is conveyed in direction D from the bulk hopper 12 over the cleaner module 14 and on to the grading module 18 comprising a grading conveyor 20. Unwanted material passes between the elements of the cleaner module and is conveyed separately.

As the crop reaches the grading conveyor 20 crop of a certain size is retained on the surface of the conveyor 20 and are conveyed onwards. Crop which is too small to be retained by the flexible mesh forming the grading conveyor 20 passes through and is collected/conveyed separately. Due to the variability of natural produce there are crop items which are of an uneven size being narrower at one end and as such tend to partially pass through the grading conveyor and become lodged therein.

As the grading conveyor 20 conveys and sort the crop, shaft 30 is caused to rotate and projections 32 mounted thereon to rotate likewise and contact the underside of the conveyor with a "beating" action. As the projections contact the underside of conveyor 20, their size and location causes them to deflect and bend as they pass over the underside of the grading conveyor 20 and make non-aggressive contact therewith.

When the projections 32 contact a lodged crop item they exert a pushing action against it which acts to lift the crop item and thus release it from the conveyor 20. The shaft 30 and associated projections 32 are located adjacent the roller 28 so as to remove lodged crop items before these are conveyed towards the roller 28 where they will be crushed and damaged.

Amongst other modifications which could be made in the above embodiments are the following. Firstly, the projections 32 could rotate in the opposite direction to the direction of travel of the conveyor 20. Secondly, the form and number of projections could be varied considerably and likewise the choice of material thereof is open to considerable variation.

Thirdly, if desired, the projections can be at spaced intervals along the usual length of the shaft 30 and around the circumference of the shaft 30, or else disposed in a helical arrangement. One further modification which can be made is that more than one shaft 30 and its associated projections 32 could be used and their positions with regard to the roller 28 varied according to requirements.

Claims (16)

1 Crop or the like conveying and grading apparatus comprising at least one driveable conveyor element characterised by a plurality of projections mounted adjacent said driveable conveyor element so as to contact the underside of said conveyor element across the width thereof to remove crop or the like lodged therein.

2 Apparatus according to claim 1 characterised by said projections being mounted on a shaft.

3 Apparatus according to claim 1 or claim 2 characterised by said projections being arranged to be rotated.

4 Apparatus according to any one of the preceding claims characterised by drive means for said projections.

5 Apparatus according to claim 4 characterised by said drive being adapted to rotate said projections in the direction of forward movement of said conveyor element.

6 Apparatus according to claim 3 characterised by the axis of rotation of said projections and a roller of said conveyor element being disposed generally parallel to each other.

7 Apparatus according to claim 3 characterised by said projections being disposed circumferentially about the axis of rotation of said shaft.

8 Apparatus according to claim 4 characterised by said drive being adapted to rotate said projections at a different speed from the rate of forward movement of said conveyor element.

9 Apparatus according to claim 8 characterised by said drive being adapted to rotate said projections at a speed of from 250 to 400% faster than the forward movement of said conveyor element.

10 Apparatus according to any of the preceding claims characterised by said projections being resiliently deflectable.

11 Apparatus according to any one of the preceding claims characterised by said projections being of flap like form.

12 Apparatus according to claim 11 characterised in that said flaps or fingers being of sufficient length so as to be resiliently deflectable over the under surface of said conveyor element to effect a beating action thereon.

13 Apparatus according to any one of the preceding claims characterised by a plurality of shafts each having its own series of projections to contact the underside of said conveyor element thereof.

14 Crop or the like conveying or grading apparatus constructed and arranged substantially as described herein with reference to the accompanying drawings.

15 A method of conveying crop or the like comprising driving a grading and conveyor element, mounting one or several projections adjacent said conveyor element across the width thereof and causing said projections to contact the underside of said conveyor element so as to remove material therefrom.

16 A method of conveying a crop or the like material substantially described herein with reference to the accompanying drawings.