GB2277046A

GB2277046A - Grading apparatus with fixed distance between adjustable soil extractor and endless grading web

Info

Publication number: GB2277046A
Application number: GB9407672A
Authority: GB
Inventors: Christopher Parkinson
Original assignee: Tickhill Engineering Co Ltd
Current assignee: Tickhill Engineering Co Ltd
Priority date: 1993-04-16
Filing date: 1994-04-18
Publication date: 1994-10-19
Anticipated expiration: 2014-04-18
Also published as: GB9307886D0; GB9407672D0; GB2277046B

Abstract

A grading apparatus comprises a soil extractor 16 having rotatable extractor elements 21 arranged for adjustable separation in the direction of advance of crop through the apparatus, and downstream of the soil extractor, a screen grader 18 having an endless grading web 26, the grading web being trained around spaced apart upstream and downstream web return rollers 23, 27 wherein an extractor element 21a at the downstream end of the soil extractor and the upstream return roller 23 are connected together by link 23a so as to maintain a fixed distance therebetween during adjustment of the separation of the extractor elements. Tensioning roller 33 takes up slack produced in the endless grading web 26 as a result of the movement of the upstream return roller 23 on adjustment of the separation of the soil extractor elements. The roller 23 may be pivotally mounted on arm 24 or arranged for sliding movement. <IMAGE>

Description

Title: Grading Apparatus Description of Invention This invention relates to a grading apparatus comprising a soil extractor having a plurality of rotatable extractor elements disposed side by side and arranged for adjustable separation in the direction of advance of articles through the apparatus and, downstream of the soil extractor, a screen grader having an endless grading web having a plurality of grading openings therein, the grading web being trained around spaced apart upstream and downstream web return means to provide a grading web upper run and a lower run disposed below the upper run, the screen grader being adapted to receive articles at its upstream end which are discharged from the downstream end of the soil extractor.

Hitherto, in order to maintain a desired relationship between the soil extractor downstream end and the upstream end of the screen grader, the whole of the screen grader and any part of the apparatus disposed downstream of the screen grader such as an inspection table, have been mounted so as to be movable as a whole backwards and forwards of the apparatus to allow for the adjustable separation of the soil extractor elements.

An object of the invention is to provide a new and improved grading apparatus whereby the above mentioned problem of wholesale movement of the screen grader and any part of the apparatus downstream thereof may be avoided.

According to the present invention we provide a grading apparatus comprising a main support means carrying a soil extractor having a plurality of rotatable extractor elements disposed side by side, and arranged for adjustable separation, in the direction of advance of articles through the apparatus and, downstream of the soil extractor, a screen grader having an endless grading web having a plurality of grading openings therein, the grading web being trained around spaced apart upstream and downstream web return means to provide a grading web upper run and a lower run disposed below the upper run, the screen grader being adapted to receive articles at its upstream end which are discharged from the downstream end of the soil extractor wherein an extractor element at the downstream end of the soil extractor and the upstream return means are maintained in a predetermined relationship during adjustment of the separation of the extractor elements and a tensioning means acts on the screen grader to take up slack produced in the endless grading web as a result of the movement of the upstream return means on adjustment of the separation of the soil extractor elements.

Preferably, the downstream soil extractor element and the upstream return means are connected together at a fixed distance apart.

The tensioning means may comprise a tensioning device engaged with a grading web to deflect the web to increase the path length of the web.

The tensioning device may be carried by a lever means pivotally mounted on the main support means for swinging movement of the tensioning means into deflecting relationship with the web.

The tensioning device may urged into engagement with the web by gravity, or by a resilient biasing means or by a mechanical linkage connected to the upstream return means of the screen trader so that movement of the upstream return means in a direction to vary the path length of the web causes movement of the tensioning device to compensatingly vary the path length of the web.

At least one of the upstream and downstream return means of the screen grader may comprise at least one roller.

The rotatable extractor elements may be carried on a plurality of shafts, said shafts being disposed side by side, and arranged for adjustable separation, in the direction of advance of articles through the apparatus and the shafts being interconnected at their ends by pairs of crossed pivotally interconnected, links.

The upstream return means may be carried by a lever means pivotally mounted on the main support means for swinging movement of the upstream return means through an arcuate movement the chord of which extends generally in said direction of advance of articles of the apparatus.

Said lever may extend upwardly from its position of pivotal mounting on the main support means.

The embodiments of the invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE 1 is a diagrammatic side elevation of a grading apparatus embodying the invention showing the soil extractor elements thereof in a first position, FIGURE 2 is a view similar to that of figure 1 but showing the soil extractor element in a second separation, FIGURE 3 is a side elevation to an enlarged scale showing one form of soil extractor of the apparatus of Figures 1 and 2, FIGURE 4 is a side elevation to an enlarged scale showing another form of soil extractor element for the apparatus of Figures 1 and 2 and, FIGURE 5 is a diagrammatic side elevation, with parts omitted for clarity, of a soil extractor of the apparatus of Figures 1 and 2.

Referring to figure 1, a grading apparatus is indicated generally at 10 and comprises a chassis 11, which provides a main support means of the apparatus and is provided with suitable ground engageable wheels 12 and carrying thereon a bulk feeder 13 in the form of an endless belt conveyor 14 driven in conventional manner by a motor 14a via a chain drive 14b.

At the downstream end 15 of the conveyor 14 a soil extractor 16 is disposed whilst at the downstream end 17 of the soil extractor a screen grader 18 is disposed. At the downstream end 19 of the screen grader there is disposed an inspection table 20.

The soil extractor 16 comprises a plurality of shafts 21 which carry either coil springs as shown in Figure 3, star shaped wheels as shown in figure 4, or discs as shown in figures 1 and 2. As shown in Figure 5, the shafts 21 are disposed side by side in the direction of advance of articles through the apparatus and interconnected by pairs of crossed pivotally interconnected links 40, 41. The shafts 21a at the downstream end of the soil separator 16, is mounted so as to be adjustable in the direction of advance of articles through the apparatus away from the shaft 21b at the upstream end of the soil extractor which is carried in bearings 42 fixed relative to the chassis 10. By moving the shaft 21a fore and aft, the separation of all the shafts 21 is adjusted by virtue of the shafts being carried by the pivotally interconnected links 40,41.

Each soil extractor shaft element 21 carries a double chain sprocket 43 whilst the upper pivotal connections between the links 40,41, carry, for free rotation, a double chain sprocket 44. The sprockets 43 are, of course, keyed or otherwise secured to rotate with the shafts 21. A first chain 45 is engaged with one set of teeth of each double sprocket 43 and one set of teeth of each double sprocket 44 whilst a second chain 46 is engaged with the second set of teeth of each sprocket 43 and one set of teeth of another sprocket 44 and so on through the whole extent of the soil extractor. One of the shafts 21 is extended to accommodate a shaft mounted motor which thus drives all the shafts 21.

The separation of the axes of rotation of the shafts is adjustable to allow for optimum cleaning of the produce. As shown in figure 1, the separation of the shafts 21 may be relatively close or, as shown in figure 2, they may be relatively spaced further apart.

Obviously the overall extent in the direction of travel of produce of the soil extractor 16 is greater when the shafts 21 are more separated, as shown in figure 2, than when they are less separated as shown in figure 1 and thus the position of the downstream end 17 of the soil extractor varies backwards and forwards along the length of the chassis 10.

In order to maintain a desired relationship, in the present example a fixed relationship, between the downstream end 17 of the soil extractor 16 and the upstream end 22 of the screen grader, the upstream return means of the screen grader which, in the present example comprises a roller 23, is mounted on a pair of spaced arms 24 for pivotal movement about an axis 25. The downstream soil extractor element 21a and the roller 23 are connected together in a fixed relationship, for example, by links 23a. Of course, if desired, some form of adjustable separation between the element 21a and the roller 23 may be provided although as a whole, the roller 23 would move to accommodate the change in position of the downstream end 17 of the soil extractor.

Also if desired, instead of the downstream soil extractor element 21a and the roller 23 being mounted on arms 24, they may be mounted for rectilinear sliding movement in suitably disposed guides, suitable means being provided to adjust the element 21a and roller 23 longitudinally of the guides and maintain them in a selected position.

The screen grader 18 comprises an endless grading web 26 having a plurality of grading openings therein. The grading web 26 is trained around the upstream return means provided by the roller 23 and a downstream return means 27 which, in the present example, also comprises a roller. Means to drive the web 26 are provided which, in the present example, comprise a motor to rotate the roller 27, although if desired, other drive means may be provided.

The upper run 28 of the grading web is also supported by further support members 29 whilst the lower run 30 passes around a further roller 31 and a tensioning device 32 which comprises a roller 33 carried on a pair of arms 34 pivoted to the chassis at 35. The roller 32 is biased downwardly by gravity, in the present example, but may be acted upon by resilient biasing means such as springs or hydraulic biasing means or by a mechanical linkage associated with the upstream roller 23 of the screen grader 18 or any other suitable means which causes the roller 32 to move to vary the path length of the web 26 to compensate for variation in its path length caused by movement of the upstream roller 32.

A transverse conveyor 36 is provided below the upper run 28 to convey articles which have passed through the grading openings to a desired discharge location.

In use, as the shaft 21a is adjusted towards and away from the shaft 21b at the upstream end of the soil extractor 16 carrying with it the roller 23, variation in the separation of the roller 23 from the roller 27 and hence the path length of the web 26 is accommodated by movement of the tensioning roller 33 as shown by the change in position of the tension roller 33 from that shown in figure 1 to that shown in figure 2.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A grading apparatus comprising a main support means carrying carrying a soil extractor having a plurality of rotatable extractor elements disposed side by side, and arranged for adjustable separation, in the direction of advance of articles through the apparatus and, downstream of the soil extractor, a screen grader having an endless grading web having a plurality of grading openings therein, the grading web being trained around spaced apart upstream and downstream web return means to provide a grading web upper run and a lower run disposed below the upper run, the screen grader being adapted to receive articles at its upstream end which are discharged from the downstream end of the soil extractor wherein an extractor element at the downstream end of the soil extractor and the upstream return means are maintained in a predetermined relationship during adjustment of the separation of the extractor elements and a tensioning means acts on the screen grader to take up slack produced in the endless grading web as a result of the movement of the upstream return means on adjustment of the separation of the soil extractor elements.

2. A grading apparatus according to claim 1 wherein the downstream soil extractor element and the upstream return means are connected together at a fixed distance apart.

3. A grading apparatus according to claim 1 or claim 2 wherein tensioning means comprises a tensioning device engaged with a grading web to deflect the web to increase the path length of the web.

4. Grading apparatus according to claim 3 wherein the tensioning device is carried by a lever means pivotally mounted on the main support means for swinging movement of the tensioning means into deflecting relationship with the web,

5. Grading apparatus according to claim 3 or claim 4 wherein the tensioning device is urged into engagement with the web by gravity.

6. A grading apparatus according to claim 3 or claim 4 wherein the tensioning device is urged into engagement with the web by a resilient biasing means.

7. A grading apparatus according to claim 3 or claim 4 wherein the tensioning device is urged into engagement with the web by a mechanical linkage connected to the upstream return means of the screen trader so that movement of the upstream return means in a direction to vary the path length of the web causes movement of the tensioning device to compensatingly vary the path length of the web.

8. A grading apparatus according to any one of the preceding claims wherein at least one of the upstream and downstream return means of the screen grader comprise at least one roller.

9. A grading apparatus according to any one of the preceding claims wherein the rotatable extractor elements are carried on a plurality of shafts, said shafts being disposed side by side, and arranged for adjustable separation, in the direction of advance of articles through the apparatus and the shafts being interconnected at their ends by pairs of crossed pivotally inter-connected, links.

10. A grading apparatus according to any one of the preceding claims wherein the upstream return means is carried by a lever means pivotally mounted on the main support means for swinging movement of the upstream return means through an arcuate movement the chord of which extends generally in said direction of advance of articles of the apparatus.

11. A grading apparatus according to claim 10 wherein said lever extends upwardly from its position of pivotal mounting on the main support means.

12. A grading apparatus substantially as hereinbefore described with reference to the accompanying drawings.

13. Any novel feature or novel combination of features as herein defined and/or shown in the accompanying drawings.