WO1993016816A1

WO1993016816A1 - Sorting apparatus and methods

Info

Publication number: WO1993016816A1
Application number: PCT/GB1993/000383
Authority: WO
Inventors: Tony Albert Russell; Geoffrey Charles Wheeler
Original assignee: Priorlucky Limited
Priority date: 1992-02-29
Filing date: 1993-02-24
Publication date: 1993-09-02
Also published as: GB9204391D0; AU3659593A

Abstract

Apparatus for sorting articles but primarily mushrooms has a chain conveyor (11) including bifurcated supports (15) projecting laterally at regularly spaced intervals and on each of which an article may be carried. Ejection stations (21), (22) and (23) are arranged along the conveyor path and at each station there are two infrared transmitters and detectors (34), (35) spaced apart to define the minimum size of article to be ejected at that station. A chain link detector (24) provides an output indicative of advancement of the chain (11). A control unit (40) receives the various detector outputs and causes actuation of ejectors (26) in a timed relationship to the advancement of the chain, to cause ejection of articles at the stations dependent upon the detected size thereof.

Description

SORTING APPARATUS AND METHODS

This invention relates to apparatus and methods f or s orting artic l e s , and in particu lar to such apparatus and methods arranged to sort articles on the basis of their sizes , whilst being transported along a conveyor path .

It is frequently necessary to sort articles dependent upon some particular characteristic of those articles. In the case of agricultural or horticultural produce, frequently there is a need to sort such produce on the basis of the physical size, which sorting operation is usually referred to as "grading". Particularly when grading eggs and mushrooms, great care must be taken not to damage the produce, else it may become unsaleable. It is a particular object of the present invention to provide apparatus for sorting articles on the basis of their physical sizes, which apparatus particularly lends itself to the grading of mushrooms.

According to one aspect of the present invention, there is provided apparatus for sorting articles, comprising: conveying means for conveying the articles along a path, there being at least one ejection station on said path at which station is provided an ejector arranged upon actuation to eject a carried article off the conveying means; detection means disposed to detect the presence of at least a part of a conveyed article projecting beyond a pre-set datum when that article is at a predetermined location and to provide an output dependent thereon; and control means to determine the presence of the article at said predetermined location and to cause actuation of the ejector dependent upon the output from the detection means.

Though the apparatus of this invention may be used to sort a variety of articles, on the basis of the physical size of each article, it nevertheless finds a particular application in the grading of mushrooms. The invention will consequently hereinafter be described with particular reference to mushrooms, though it is to be understood that the invention is not limited thereto .

The conveying means may take a variety of forms, but preferably comprises a conveyor having a plurality of supports each adapted to support a mushroom (or other article) to be conveyed. For example, the conveying means may comprise a plurality of links hinged together to form an endless chain, with the supports being equi-spaced along the length of the chain. Conveniently, the chain is disposed with the pivotal axes between the links disposed generally vertically, and with the supports projecting laterally from that chain. In this case, each of said supports may comprise a pair of generally parallel arms projecting laterally from the chain_/ whereby the cap of a mushroom may be carried by said arms, with the stalk depending downwardly between those arms.

In order to facilitate the easy insertion of and the ejection of mushrooms from those supports, it is preferred for the arms to be raked back with respect to the direction of advancement of the conveyor along said path.

Advantageously, the control means includes position means to provide an output when a carried mushroom is at the predetermined location in the ejection station. Such position means may be disposed a pre-set distance (and normally a multiple of the support spacing) spaced from the ejection station, and arranged to produce an output by interaction with the conveying means at that point. Preferably, the ejector comprises a pusher disposed on actuation to push a carried article off the support, the pusher being actuated for example by means of a pneumatic ram or an electric solenoid. More than one such pusher may be provided at the or each ejection station, to permit increased speed of operation, and better distribution of ejected produce, in a container therefor.

There may be provided more than one ejection station along the length of the conveying path, to allow the grading of mushrooms into a number of different grades. The last ejection station should be configured to discharge from the conveyor any mushrooms not ejected at the, or at any one of the, previous ejection stations. This last ejection station may be similar to the other stations, or may comprise a plurality of substantially parallel rotatably-mounted rollers, the plane containing the axes of the rollers lying at an angle to the line of advancement of the mushrooms carried by the conveyor.

The conveying means may define a generally J- shaped conveying path, which facilitates the positioning of the apparatus close to growing mushrooms . The apparatus may thus be loaded easily and rapidly by a human operator.

According to a second aspect of the present invention, there is provided a method of grading articles on the basis of the size of those articles, comprising: loading the articles on to conveying means arranged to convey the articles along a path, there being at least one ejection station on said path at which station is provided an ejector arranged upon actuation to eject a carried article off the conveying means; determining the presence of a carried article at a predetermined location in the ejection station; detecting the presence of at least a part of a conveyed article projecting beyond a pre-set datum when that article has been determined as being at said predetermined location in the ejection station and providing an output dependent thereon; and causing actuation of the ejector dependent upon the output from the detection means. The invention further extends to a conveyor for mushrooms, comprising a plurality of hinged links forming an endless chain, and a multiplicity of supports for mushrooms, each support being connected to a respective link of the chain and comprising-a pair of generally parallel arms projecting laterally of its link, whereby the cap of a mushroom may be carried by said arms with the mushroom stalk depending downwardly between said arms.

By way of example only, one specific embodiment of mushroom grading apparatus constructed and arranged in accordance with the present invention will now be described in detail, reference being made to the accompanying drawings, in which:- Figure 1 is a diagrammatic plan view of the grading apparatus of this invention;

Figure 2 is a detail view on a sizing and ejector station used in the grader of Figure 1;

Figure 3 is a detail view on a link-sensing part of the apparatus of Figure 1; Figure 4 is diagrammatical vertical section through the link-sensing part of Figure 3; and Figure 5 is a detailed side view on an ejector.

Referring to the drawings, there is shown a grader intended for the grading of mushrooms, on the basis of the physical size of those mushrooms. Figure 1 shows a guide assembly 10 having in plan a general J-shape and within which are drive and take-up wheels and guides (not shown) to guide an endless chain 11 (shown in part in Figures 2 and 3 ) around the path defined by the guide assembly. The chain 11 is made up of simplex links 12 hinged together by means of pins 13, and duplex connector links 14 at every third pitch of the chain. Connected to each link 14 is a laterally projecting support 15 having a pair of arms 16 between which is a slot 17, the length of the slot 17 being raked back having regard to the direction of movement of the chain 11, shown by arrow A in Figure 2. When mounted within the guide assembly 10, the pins 13 of the chain 11 lie essentially vertically, with the supports 15 projecting laterally outwardly of the chain 11, in a generally horizontal plane.

As shown in Figure 1, for much of the length of the guide assembly 10 the supports 15 lie within the confines of that guide assembly, but on the outer run 19 of the chain around the guide assembly, the supports 15 project beyond the guide assembly, so giving access to the arms 16 and the slots 17 therebetween. Mushrooms may be carried by the supports 15, one on each support, with the cap resting on the arms 16 and the stalk projecting down through slot 17. Arranged along the linear part of the outer run 19 along which the chain 11 is caused to move are, in order, a stalk cutter 20, first and second ejection stations 21 and 22, an exit ejection station 23, and a link sensor 24. Each of these will be described in turn, below.

The stalk cutter 20 comprises a motor-driven cutting disc 25 arranged with its axis substantially vertical and with the disc below the line of movement of the supports 15, the disc co-acting with a fixed cutter blade and positioned to cut off the lower part of a stalk of a conveyed mushroom. The vertical position of the disc 25 is adjustable, in order that the length of the stalk remaining attached to a cap carried by the arms 16 may be selected as required. The first and second ejection stations 21 and 22 are similar and like reference characters are used for like parts in each station. At each station (Figure 4), there is provided a pair of ejectors 26, each having a solenoid 27 operating on an armature 28 coupled to a lever 29, surfaced with a soft resilient material 31. The lever 29 is biased to the position shown in Figure 5 by means of spring 32. Energisation of the solenoid 27 thus causes movement of the plate 30 against the spring bias, to move the plate 30 laterally over the support 15 for the time being located at the station.

Also located at each ejection station is an adjustable detector unit 33 comprising two spaced pairs of infra-red transmitters and detectors 34 and 35, the lines of action 36 and 37 of which extend generally across the path along which the mushrooms are advanced. The transmitter and detector 34 are fixed, but transmitter and detector 35 are adjustable in the direction of arrow B by rotating hand-wheel 38 to permit selection of the minimum size of mushroom which will be ejected at that station.

The exit ejection station 23 is similar to ejection stations 21 and 22, and like parts are given like reference characters. Only one transmitter and detector 34 are provided, at a fixed position, to control the operation of the ejectors 26, following the detection of a conveyed mushroom not ejected at either of the previous stations.

Figures 3 and 4 show the link sensor 24 arranged to sense the presence of a duplex link 14, and mounted on the guide assembly 10 immediately after the exit ejection station 23. The link sensor 24 may operate electro-magnetically, or optically. The position of the sensor 24 is adjustable along the length of the conveying path to ensure exact timed sensing of the duplex links relative to the ejection stations, and provides an output to a control unit 40 each time a duplex link is detected. The arrangement is such that at the precise instant a link is detected by sensor 40, supports 15 are aligned with the ejectors 26; the spacing between the two ejectors at each station is twice the support pitch, and the spacing between the ejectors of the various stations is a multiple of that pitch. The fixed detector 34 is however spaced by less than a whole pitch from the adjacent ejector.

The control unit 40 is arranged to monitor the outputs of the detectors 34 and 35 and also of the link sensor 24. If both detectors 34 and 35 at a station produce an output, a mushroom is sensed to be large enough to be ejected; that information is carried forward with the advancement of the chain so that the mushroom is ejected by one of the ejectors 26 when the mushroom is aligned therewith, timed by the link sensor 24. If a mushroom has not been ejected at either the first or second ejection stations then it will be ejected from its support at the exit ejection station 23. Positioned beneath the ejectors at the various stations are respective boxes 41, to receive ejected mushrooms.

It will be appreciated that by adjusting the effective lines of action 37 of the adjustable detectors 35, grading of carried mushrooms may be performed on the basis of the size of those mushrooms. If, at the first station 21, the moment the fixed detector senses the front edge of a mushroom cap crossing the line of action 36 thereof, the output from the adjustable detector is checked; if there is no output indicative of a mushroom thereat, the mushroom is deemed too small for ejection, but if outputs are simultaneously obtained from both detector 34 and 35, then the mushroom is deemed sufficiently large for ejection. If not ejected at the first station, a similar test is applied at the second station, whereat the spacing between the detectors 34 and 35 is smaller than at the first station. If the adjustable detector 35 still does not produce an output when there is an output from the fixed detector 34, because the mushroom is still too small, again that mushroom will not be ejected. The mushroom will however be ejected at the exit ejection station 23, where the sensor 34 is provided merely to inhibit the action of the ejectors 26 should no mushrooms be present. Mushrooms may be loaded on to the supports 15 either manually or with automatic machinery, as the supports move round the curved part of the outer run, in advance of the stalk cutter 20. If loaded manually, the operator may stand on the inner side of the curved part of the run, with trays of mushrooms being advanced automatically past the outer part, as shown by arrow C on Figure 1. The operator may then harvest the mushrooms and place them on the supports 15, for stalk- cutting and grading, as described above.

Claims

1. Apparatus for sorting articles, comprising: conveying means for conveying the articles along a path, there being at least one ejection station on said path at which station is provided an ejector arranged upon actuation to eject a carried article off the conveying means; detection means disposed to detect the presence of at least a part of a conveyed article projecting beyond a pre-set datum when that article is at a predetermined location and to provide an output dependent thereon; and control means to determine the presence of the article at said predetermined location and to cause actuation of the ejector dependent upon the output from the detection means.

2. Apparatus as claimed in Claim 1, wherein the conveying means comprises a conveyor having a plurality of supports each adapted to support an article to be conveyed.

3. Apparatus according to Claim 2, wherein the conveying means comprises a plurality of links hinged together to form an endless chain, said supports being equi-spaced along the length of the chain and each of said supports being connected to a respective link to project laterally from the chain.

4. Apparatus as claimed in Claim 2 or Claim 3, wherein the control means includes position means to detect the presence of a support at a point spaced from the ejection station by a pre-set distance.

5. Apparatus as claimed in any of Claims 2 to 4 and adapted for use in sorting mushrooms, wherein each of said supports has a pair of generally parallel arms projecting laterally of the conveyor, whereby the cap of a mushroom may be carried by said arms with the stalk depending downwardly between said arms.

6. Apparatus as claimed in Claim 5, wherein the arms are raked back with respect to the direction of advancement of the conveyor along said path.

7. Apparatus as claimed in Claim 5 or Claim 6, wherein there is provided a stalk cutter for the stalks of carried mushrooms to cut said stalks to a uniform length, which stalk cutter is disposed on said path upstream of said ejection station.

8. Apparatus as claimed in any of the preceding Claims, wherein said ejector comprises a pusher disposed to push a carried article off the conveyor, and drive means to effect movement of said pusher, operable by the control means in synchronism with the advancement of the conveyor.

9. Apparatus as claimed in Claim 8, wherein said drive means comprises one of a pneumatic ram or an electric solenoid.

10. Apparatus as claimed in any of the preceding Claims, wherein there is provided a second ejection station similar to the first-mentioned ejection station and spaced along the path therefrom.

11. Apparatus as claimed in Claim 10, wherein the last ejection station on the path serves to eject from the conveyor any articles still carried by the conveyor on reaching that station.

12. Apparatus as claimed in any of the preceding Claims, wherein the detection means comprises an infra-red transmitter and detector pair arranged to monitor the presence of a part of an article projecting over said datum in the ejector station.

13. Apparatus as claimed in any of the preceding Claims, wherein the detection means includes an infra¬ red transmitter and detector pair arranged to detect the presence of the article at said predetermined location.

14. Apparatus as claimed in Claim 12 and Claim 13, wherein the spacing between the respective lines of action of the two infra-red transmitter and detector pairs is adjustable.

15. A method of grading articles on the basis of the size of those articles, comprising: loading the articles on to conveying means arranged to convey the articles along a path, there being at least one ejection station on said path at which station is provided an ejector arranged upon actuation to eject a carried article off the conveying means; determining the presence of a carried article at a predetermined location in the ejection station; detecting the presence of at least a part of a conveyed article projecting beyond a pre-set datum when that article has been determined as being at said predetermined location in the ejection station and providing an output dependent thereon; and causing actuation of the ejector dependent upon the output from the detection means.

16. A method as claimed in Claim 14, wherein the size detection of the conveyed articles is performed by a pair of infra-red transmitter and detector pairs the lines of action of which are substantially parallel and the spacing between which is adjustable, said transmitter and detector pairs providing respective outputs to a control means for the ejectors dependent upon the presence or otherwise of an article in the line of action of the pair.