GB2428548A

GB2428548A - Sorting apparatus

Info

Publication number: GB2428548A
Application number: GB0516207A
Authority: GB
Inventors: Geoffrey William Sweet; James Charles Runham
Original assignee: HARPLEY ENGINEERING Ltd
Current assignee: HARPLEY ENGINEERING Ltd
Priority date: 2005-08-06
Filing date: 2005-08-06
Publication date: 2007-02-07
Anticipated expiration: 2025-08-06
Also published as: GB0516207D0; GB2428548B

Abstract

Sorting apparatus comprises a feed conveyor 11, a guide member 21 which receives items one at a time from the feed conveyor 11 and whereat the quality of a received item is assessed in real-time, to produce a signal for a router 26 disposed immediately downstream of the guide member. When the router 26 is inactive, an item continues along a normal path 12 from the guide member 21 but when active the router deflects an item to an alternate path 17. The router 26 comprises a pivotally mounted deflector plate 27 which is pivoted on receipt of a signal dependent upon the determined quality of an item, to project into and block the normal path 12 for that item and so deflect the item to the alternate path 17. The deflector plate 27 is pivoted at its downstream end about an axis transverse to the length of the normal path 12 whereby the plate may be moved rapidly to its active position.

Description

SORTING APPARATUS

This invention relates to sorting apparatus and in particular (but not exclusively) to apparatus intended for the sorting of agricultural produce, such as root crops, nuts and so on.

Though this invention is primarily concerned with the classification or grading of agricultural produce of various kinds, it may be used to sort such produce from foreign matter which may be entrained with the produce. For example, in the case of root crops, stones or clods of earth may be picked up and carried with the produce. The invention is however applicable to the sorting, grading and classification of other objects besides agricultural produce and so the invention is not to be regarded as being limited to the sorting of agricultural produce, though it will hereinafter be described primarily with reference to agricultural usage.

There have been very many proposals for the sorting of grown produce by class or grade. Most of these proposals aim at assessing some particular property of the produce and then making a decision as to the appropriate classification for each item, dependent upon the assessed property. For example, a grader may determine one or more of the weight, colour and size of each item of produce whereafter that item is directed along an appropriate path or into an appropriate bin, dependent upon the value of the or each assessed property. At its simplest, such a grader may have two paths or bins, one for selected items and the other for rejected items, though graders having many separate paths for classified items are known.

In order to increase productivity, there is a requirement for a grader to operate as quickly as possible. Such apparatus is required to work on a continuous basis but the assessment of the monitored property takes a finite time, whereafter some kind of router must operate to direct each item along the appropriate path for the assessed value of the monitored property. If the line speed is increased, there may be insufficient time to complete the property determination and then operate the router as appropriate. Increasing the separation between the monitoring station at which the property is assessed and the router increases the time available for completing the determination of the monitored property, but then the overall physical size of the grader is increased.

Conventionally, the problem of increasing throughput has been addressed by providing a grader with several lanes each having equipment for determining the property to be assessed, for each item being advanced along the lane. Each lane is also provided with an individual router for directing an assessed item along the appropriate path. However, the provision of a number of parallel lanes increases the cost of the equipment as well as its physical size, which latter can be a significant disadvantage for portable apparatus, intended to be used for example in a field where the produce is harvested.

It is a principal aim of apparatus of this invention to address the problem of increasing the speed of operation of sorting apparatus which may already have several separate lanes, without correspondingly increasing the separation between the item assessment station and the router, or adding extra lanes.

According to this invention, there is provided sorting apparatus comprising feed conveying means for items to be sorted, a guide member which receives items one at a time from the feed conveying means and whereat a quality of a received item is assessed in real time, and a router driven by a signal derived from the assessment of an item which router when inactive allows an item to continue along a normal path from the guide member but when active deflects an item to an alternate path, said router comprising a pivotally-mounted deflector plate which when inactive lies in the general plane of the normal path but which is pivotally movable to project into and block the normal path thereby deflecting an item to the alternate path, the deflector plate being pivoted about an axis transverse to the length of the normal path at or adjacent the downstream end of the deflector plate, and being pivotal so that the upstream end of the deflector plate is moved into the path of the advancing items.

It will be appreciated that the router arrangement of this invention allows the deflector plate to be positioned close to the property assessing station while still permitting relatively high line speeds for items to be sorted. The particular configuration of deflector plate is able to operate very quickly in response to the signal derived from the assessment of the property of the item for causing the deflection of the item from the normal path to an alternate path. In view of this, the throughput speed is limited by the speed of operation of the assessment of the monitored property, without the need to position the router significantly removed from the assessment station.

Satisfactory operation of the sorting apparatus of this invention requires rapid real-time processing of the quality of each item received on the guide member. For example, a weighing cell may be associated with that guide member to permit the assessment of the weight of an item received thereon.

Preferably, however, the guide member is caused to resonate by an item dropping on to that member from the feed conveying means, the induced resonance of the guide member then being analysed rapidly in order to give an appropriate signal to the router, for the deflector plate either to remain in its normal inactive setting or to be moved to its active setting and so deflect an item to the alternate path.

For maximum throughput, it is thus important that the property of an item received on the guide member is assessed very quickly and so before the item has advanced to the router, and for the deflector plate of the router to be movable very quickly in response to a signal derived from the assessment of an item, to direct that item to the alternate path if the assessment indicates the item should not proceed along the normal path.

In a preferred embodiment, the guide member and the deflector plate are both generally planar. When the deflector plate is in its inactive position, both the guide member and the deflector plate preferably lie in a substantially common plane, the deflector plate being moved out of that common plane to its active position. That common plane may be inclined downwardly from the discharge end of the feed conveying means, with the plate pivoted for example about an axis lying transversely beneath the plate, adjacent its downstream end.

It is important that the deflector plate may be moved rapidly between its inactive and active positions, and to that end it is preferred for there to be a linear actuator, such as a solenoid or a double-acting pneumatic ram, arranged to pivot the plate. The actuator may be mounted on a fixed part of the apparatus and be pivoted to the deflector plate between its pivotal axis and the upstream end thereof.

In a preferred embodiment, the downstream end of the deflector plate, when in its inactive position, leads to a discharge conveying means which forms a part of the normal path for the items. A further conveying means may be arranged to receive items deflected by the deflector plate when in its active position, which further conveying means forms a part of the alternate path for the items. Typically, the further conveying means may extend in a direction substantially normal to the direction in which the discharge conveying means extends.

The feed conveying means, discharge conveying means and further conveying means all may comprise endless belt conveyors, as appropriate for the items being sorted.

The discharge end of the feed conveying means may be divided into a plurality of lanes, each lane being provided with at least one guide member and a deflector plate. Each deflector plate may direct an item advancing along the respective lane either on the normal path or to the alternate path, depending upon the result of the assessment.

By way of example only, one specific embodiment of sorting apparatus of this invention and for use typically with root vegetables will now be described in detail, reference being made to the accompanying drawings:Figure 1 is a general isometric drawing showing the arrangement of the sorting apparatus; Figure 2 is a detail view on an enlarged scale of the guide members and deflector plates; and Figure 3 is a diagrammatic side view of the router region of the sorting apparatus.

Referring to the drawings, there is shown sorting apparatus arranged as a grader to direct items such as potatoes or sugar beet into one of two separate classes. The apparatus comprises a main frame 10 supporting an input feed conveyor 11 and a main discharge conveyor 12. The conveyors 11, 12 each comprise endless belt conveyors driven by respective gearbox electric motors 13, 14. The input feed conveyor 11 extends generally horizontally, for receiving items of the root crop to be sorted. Such items are fed on to the conveyor 11 typically from another conveyor or from a hopper, in a manner well known in the art and which will not be described further here. The main discharge conveyor 12 is inclined upwardly and is provided with slats 15, to carry produce deposited thereon to a discharge end 16, from which the produce may fall for example into a bin, the container of a truck, or the like.

The sorting apparatus includes an alternate discharge conveyor 17, extending generally horizontally and transverse to the input feed conveyor and main discharge conveyor, adjacent to the lower end of the main discharge conveyor 12. The alternate discharge conveyor 17 also is a simple belt conveyor driven by a gearbox electric motor 18.

The input feed conveyor 11 is divided into a plurality of lanes by side plates 19 profiled to fit closely to the upper run and discharge end 20 of the input feed conveyor, whereby articles conveyed by the feed conveyor 11 are divided by the side plates 19 into individual parallel lanes. Those side plates extend downwardly from the discharge end 20 of the conveyor 11 to the lower end of the main discharge conveyor 12.

Disposed immediately below the discharge end of the feed conveyor 11 is a plurality of guide members 21, arranged in groups of four with a group disposed in each lane, respectively. Each guide member 21 is resiliently supported on rubber mounts 22 carried on a part (not shown) of the main frame 10, each guide member having associated therewith a vibration detector 23 disposed on the underside of the member. Typically, the vibration detector comprises a housing secured to the underside of the guide member, with an accelerometer and an electronic circuit disposed therein. The circuit is arranged to analyse very rapidly and in real time the vibrations of the guide member on being struck on its upper surface by an item of produce falling thereon, from the discharge end 20 of the feed conveyor. Each vibration detector is connected by a respective cable 24 to a communication unit (not shown) mounted within the frame 10, where the processed signals from the vibration detectors are directed to the appropriate routers, to be described below.

Downstream of each group of four guide members and so disposed between those guide members and the lower end of the main discharge conveyor 12, is a respective router 26. There is one such router for each lane, each router comprising a deflector plate 27 pivotally mounted to the main frame about a shaft 28 extending transversely to all of the deflector plates, through bearings provided in U-shaped brackets 29 mounted on the underside of the plates 27. Also connected to the bracket 29 of each deflector plate 27 is a respective double-acting ram 30, one for each deflector plate 27, arranged such that expansion of a ram 30 causes the associated deflector plate to pivot counter-clockwise (as shown in Figure 3) and so project upwardly into the path between the group of four guide members 21 of that lane and the main discharge conveyor 12. Each deflector plate 27 and bracket 29 could instead comprise a one-piece plastics moulding.

An elongate in-fill bar 31 extends between the downstream end of the several deflector plates 27 and the lower end of the main discharge conveyor 12, to guide produce passing over the deflector plates 27 when in their inactive settings, as shown in the drawings, on to the main discharge conveyor. When an item of produce is to be directed on to the alternate discharge conveyor 17, the pneumatic ram 30 of the appropriate lane is expanded so pivoting upwardly the upstream end 32 of the deflector plate. The plate thus lies wholly in the path of items from the four guide members 21 of that lane to the main discharge conveyor 12, and so the item of produce is deflected downwardly on to the alternate discharge conveyor 17, to be carried transversely away from the main discharge conveyor 12. After a pre-set time the ram 30 is contracted again, to return the deflector plate to its inactive setting.

In the event that the next following item of produce is of a satisfactory condition, as assessed by the analysis of the vibration of the guide members 21 on that next item dropping thereon from the discharge end 20 of the conveyor 11, the deflector plate remains in its inactive setting, as best seen in Figure 3.

The configuration of the deflector plate 27 together with its pneumatic ram 30 allows the plate to be moved very rapidly between its inactive setting (shown in Figure 3) and its active setting where it blocks the path between the guide members 21 and the main discharge conveyor 12, and then back again, in response to signals derived from the assessment performed at the guide members.

In the foregoing sorting apparatus, produce is assessed by allowing each item of produce to fall from the discharge end 20 of the feed conveyor 11 on to the guide members 21 of a given lane, to cause those members to vibrate. The resonance is then analysed in real time to produce the required signal for controlling the operation of the router 26 associated with that lane, before the item reaches the router. Thus, the processing of the signal obtained from the accelerometers of each vibration detector must be performed very rapidly in order to allow the router to be operated, if needed, before the item passes the reove r.

Other properties of an item of produce may be determined in different ways, for controlling the operation of the router. For example, load cells or weighing cells could be associated with the guide members 21 for determining - 10- the weight of each item. Another possibility would be to determine the colour of each item and then to control the router dependent upon the determined colour.

To allow for these various possibilities, the distance through which each item of produce falls on to the guide members 21 and the angle of inclination of the guide members 21 and so also of the deflector plates 27 in the routers may be changed to suit the produce and the assessment being carried out.

Claims

1. Sorting apparatus comprising feed conveying means for items to be sorted, a guide member which receives items one at a time from the feed conveying means and whereat a quality of a received item is assessed in real time, and a router driven by a signal derived from the assessment of an item which router when inactive allows an item to continue along a normal path from the guide member but when active deflects an item to an alternate path, said router comprising a pivotally-mounted deflector plate which when inactive lies in the general plane of the normal path but which is pivotally movable to project into and block the normal path thereby deflecting an item to the alternate path, the deflector plate being pivoted about an axis transverse to the length of the normal path at or adjacent the downstream end of the deflector plate, and being pivotal so that the upstream end of the deflector plate is moved into the path of the advancing items.

2. Sorting apparatus as claimed in claim 1, wherein the guide member and the deflector plate are both generally planar and when the deflector plate is in its inactive position, the guide member and the deflector plate both substantially lie in a common plane.

3. Sorting apparatus as claimed in claim 2, wherein the common plane is inclined downwardly from the discharge end of the feed conveying means.

4. Sorting apparatus as claimed in any of the preceding claims, wherein the deflector plate is pivoted about an axis lying beneath the plate, adjacent its downstream end. - 12-

5. Sorting apparatus as claimed in any of the preceding claims, wherein a linear actuator is provided to effect pivoting movement of the deflector plate between its inactive and active positions, mounted below the deflector plate.

6. Sorting apparatus as claimed in claim 5, wherein said actuator comprises one of a solenoid or a double-acting pneumatic ram.

7. Sorting apparatus as claimed in claim 5 or claim 6, wherein the actuator is mounted on a fixed part of the sorting apparatus and is pivoted to the deflector plate between the pivotal axis of the plate and the upstream end thereof.

8. Sorting apparatus as claimed in claim 7, wherein a bracket is provided on the underside of the deflector plate, a support shaft for pivotally mounting the deflector plate being journalled in the bracket and the actuator also being pivoted to the bracket.

9. Sorting apparatus as claimed in any of the preceding claims, wherein the feed conveying means comprises an endless belt conveyor.

10. Sorting apparatus as claimed in any of the preceding claims, wherein the downstream end of the deflector plate when in its inactive position leads to a discharge conveying means forming a part of said normal path for the articles.

11. Sorting apparatus as claimed in any of the preceding claims, wherein there is provided a further conveying means on to which the items are deflected by the deflector plate when in its active position, which further conveying means forms a part of said alternate path for the articles.

12. Sorting apparatus as claimed in claim 11, wherein the further conveying means extends in a direction substantially normal to the direction in which the discharge conveying means extends.

13. Sorting apparatus as claimed in claim 10, wherein the discharge conveying means comprises an endless belt conveyor.

14. Sorting apparatus as claimed in claim 11 or claim 12, wherein the further conveying means comprises an endless belt conveyor.

15. Sorting apparatus as claimed in any of the preceding claims, wherein the discharge end of the feed conveying means is divided into a plurality of lanes, each lane being provided with at least one guide member and a deflection plate.

16. Sorting apparatus as claimed in claim 15, wherein each lane has a plurality of co-planar guide members arranged side by side.

17. Sorting apparatus as claimed in any of the preceding claims, wherein each guide member is provided with a vibration detector the output of which is processed to provide said signal for controlling the router.

18. Sorting apparatus as claimed in claim 17, wherein the vibration detector comprises an accelerometer the output of which is fed to an electronic circuit incorporated within the vibration detector mounted on the guide member.

19. Sorting apparatus as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.