GB2242895A

GB2242895A - Denesting stacked articles

Info

Publication number: GB2242895A
Application number: GB9107805A
Authority: GB
Inventors: Alan James Fletcher
Original assignee: FLETCHER HARRISON Ltd
Current assignee: FLETCHER HARRISON Ltd
Priority date: 1990-04-12
Filing date: 1991-04-12
Publication date: 1991-10-16
Also published as: GB9107805D0; GB9008417D0

Abstract

An apparatus for automatically denesting polystyrene trays 16 (not shown) with peripheral flanges from a nested stack of such trays comprises a pair of structures 40, each having two component parts which are rotatable together within a housing 10, on opposed sides of a tray cassette above a conveyor. Each component part is profiled to have at least one supporting edge which can project through an opening 32 in a wall 30 of the respective housing below the stack of trays for engagement with the flanges of the trays. The profile of each component part is such that, on rotation, a supporting edge is alternately presented through the housing and then withdrawn into the housing. The supporting edges of the respective component parts are angularly displaced so that when support is removed from a lowermost one of the trays 16, the flange of the next to lowermost one of the trays 16 is simultaneously supported thereby to continue to support the stack. The component part 40 is formed with a cam surface which denests the lowermost unsupported one of the trays 16 onto the conveyor. <IMAGE>

Description

Denesting of Stacked Articles This invention relates to the denesting of stacked articles, and is particularly concerned with articles having peripheral flanges such as trays made, for example, of plastics materials.

While plastics trays designed to nest within one another are therefore convenient for storage purposes, problems have been encountered in attempting to prova.de apparatus which can automatically denest such trays, without the apparatus being complicated and therefore expensive.

Consequently most denesting of such plastics trays is presently carru.ed out by hand.

According to the present invention there is provided apparatus for denesting articles with peripheral flanges from a nested arrangement thereof, the apparatus comprising means for supporting a plurality of nested articles, means for separating an outermost one of the articles from the others while maintaining support of said others, and means for effecting alternate functioning of the supporting means and the separating means, whereby to successively separate outermost ones of the articles from the nested arrangement.

Preferably the supporting means comprises first rotatable components at spaced locations, each said first rotatable component being profiled to alternately present a surface in alignment with the flanges of the nested articles and remove a surface from said alignment.

Preferably also the separating means comprises second rotatable components at spaced locations, each said second rotatable component being profiled to alternately present a surface in alignment with the flanges of the nested articles and remove a surface from alignment, the surface having cam means adapted to co-act with the article flanges and thereby effect separation of an outermost article from the other nested articles.

Each of said first rotatable components may be z.nteg- rally formed as a pair with a respective one of said second rotatable components, and the integral pair of components may have respective edges in parallel spaced planes and angularly spaced. Alternatively, each of said first rotatable components may form a pair with a respective one of said second rotatable components, the components of the pair being separately formed. The rotatable components of each pair may be angularly adjustable relative to one another.

Also, the rotatable components of each pair may be spaced from one another, and the spacing is adjustable.

The means for effecting alternate functioning may comprise a drive for imparting rotation to each pair of components. The latter may be mounted for rotation with a pulley and the drive may be in the form of an endless belt which wraps around each of the pulleys and around a plurality of further pulleys, one of which is operatively connected with the drive. The pulleys associated with the respective pairs of components may be movably located whereby to adjust the spacing between the pairs of components.

The present invention also provides a method of denesting articles with peripheral flanges from a nested arrangement thereof, the method including the steps of supporta.ng a plurality of nested articles, separata.ng an outermost one of the articles from the others while maintanning support of said others, and alternately effecting the supporting and separating, whereby to successive 1 y separate outermost ones of the articles from the nested arrangement.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which : Fig. 1 is a diagrammatic representation of part of a denesting apparatus; Fig. 2 is a schematic plan of part of an apparatus according to the invention; Fig. 3 is a sectional side elevation substantially corresponding to Fig. 2; Fig. 4 is a schematic plan of a component of the apparatus; Fig. 5 is a side elevation of the component of Fig. 4; Fig. 6 is an end elevation of the component of Fig. 4; and Fig. 7 is a sectional side elevation through an alternative design of the component of Figs. 4 to 6.

At the present time, articles in the form of trays having peripheral flanges and being formed for example of polystyrene, are commonly used in many industries. The trays may be used for receiving foodstuffs which are then sealed in the trays by a transparent plastics film wrapped therearound. Such trays are designed, when empty, to nest within one another for ease of storage.

To enable automatic denesting of such trays, a structure 10 (Fag. 1) is adapted to bridge a conveyor 12, with the structure 10 receiving a cassette 14, the latter being aligned with an opening in the structure 10 and having an open lower end thereby located above the conveyor 12. The cassette 14 may be of any suitable design to accommodate a nested arrangement of polystyrene trays 16 vertically above the conveyor 12.

With reference to Figs. 2 and 3, the structure 10 has a base 18 and a cover 20 parallel to, but spaced therefrom, by end and side walls 22 whereby to define a cavity between the base 10 and the cover 20. The cavity opens onto a pair of opposed sides of the through opening 16 and movably locates a housing 24 at each of the opposed sides. Each of the housings 24 has a base 26 in sliding face-to-face contact with the base 18, and a cover 28 in sliding face-to-face contact with the cover 20. The housings 24 present facing outer walls 30 at the opposed sides of the through opening 16 and each wall 30 has a through opening 32 therein in the form of a slot for a purpose hereinafter described. Movement of the housings 24 towards and apart from one another varies the width of the through opening 16 to accommodate different sizes of cassettes.Consequently different sizes of trays can be accommodated with 3. n the one apparatus.

Rotatably mounted on the base 26 of each housing 24 is a pulley 34. A plurality of other pulleys 36 are rotatably mounted within the structure 10 with an endless drive belt 38 extending therearound. A motor 39 is mounted within the structure 10 and imparts drive to one of the pulleys 36.

Thereby the belt 38 effects rotation of the other pulleys 34, 36 and, as the pulleys 34 are of the same diameter, they have the same speed of rotation.

Mounted for rotation with each of the pulleys 34 and extending thereabove within the cavity of the structure 10 is a structure 40 (Figs. 4 to 6) for carrying out denesting of the trays. Each structure 40 comprises a component part 42 of generally circular configuration but cut away at each of two opposed locations along a respective edge 44. Each structure 40 further has a component part 46 of generally circular configuration providing a planar circular plateau 48 with a bevelled periphery 50. The part 46 is cut away at each of opposed locations along a respective edge 52, similar to the part 42, but the opposed locations are 900 removed from the corresponding opposed locations of the part 42. On each remaining part circular peripheral surface, between the cut away portions, the part 46 has an extension 47 from the plateau 48 locating alongside the respective cut away portion of the part 42 and the extension 47 is profiled on its outer edge to present a cam surface 54 for a purpose hereinafter described.

The location of each structure 40 in the respective housing 24 is such that edges of the parts 42, 46 can extend through the respective opening 32 in the housing wall 30 and beyond the outer face of the latter, except when the respective cut away portion is presented to the housing wall 30, when the edges of respective parts 42, 46 will not then extend beyond the outer face of the wall.

When a cassette 14 is loaded on the structure 10, the structures 40 are set up whereby the supporting edges of the parts 42 extend beyond the outer faces of the housing walls 30, so that the nested trays 16 from the cassette 14 can be supported by the parts 42 which abut the lower face of the flange of a lowermost one of the trays. Rotation of the structures 40 will then move the cut away portions of the parts 42 into the housing walls 30 and thereby remove support from the lowermost one of the trays. Simultaneously however the supporting edges of the parts 46 will extend through the housing walls 30 and will engage below the flange of the next to lowermost one of the trays, thereby to support the stack of trays.

In this situation, gravity may not be sufficient to separate the lowermost unsupported one of the trays from the stack, but further rotation of the structures 40 will cause the respective cam surfaces 54 to co-act with the flange of the lowermost tray and effectively push the latter downwardly from the stack and therefore denest the tray which will fall onto the conveyor 12. Thereafter the stack of trays will drop downwardly but will be caught by the then protrud ing edges of the parts 42 so that the sequence of denesting can again commence.

Referring to Fig. 7, the denesting structure 40 can be formed in two parts whereby the relative positions of the supporting edges of the parts 42, 46 can be varied in order to suit a particular application of the apparatus, e.g. the type of tray involved or the required speed of denesting.

In this embodiment the parts 42, 46 are independent of one another, the part 42 being provided with upstanding flanges 56 inwardly of the supporting edges thereof, and the part 46 having depending flanges 58 at the respective edges 52 thereof, whereby the flanges 56, 58 can lie alongside one another with the flanges 58 outermost whereby to provide for correct location of the parts 42, 46. The part 42 has a central through aperture which is countersunk and receives an externally threaded bolt 60, the part 46 having an internally threaded central hub 62 facing inwardly thereof so as to receive the threaded end of the bolt 60. The outer end of the bolt 60 has a slot 64 to receive a tool whereby rotation of the bolt 60 can adjust the height of the part 46 above the part 42 to suit the particular application of the component.Springs 66 are located internally of the component to extend between the parts 42, 46 so as to bias the latter apart.

There is therefore provided an apparatus which can effect automatic denesting of trays or other articles from a stack. It is essential that the synchronized operation of the components 40 be maintained and the drive arrangement provided can achieve this. For different applications, l.e.

different sizes and designs of tray or different operating speeds, different designs of denesting structure may be utilised. For example, the cam surfaces may be altered and selected edges of the base part 42 may be chamfered to avoid filing of the trays. Also, each of the parts 42, 46 may be cut away at only one location with the part 46 thereby requiring to provide only one cam surface. Further, provision may be made for the parts 42, 46 when separately formed, to be rotatable relative to one another.

It is to be appreciated that, while the described apparatus provides for adjustment in one direction across the opening in the structure 10 through which the trays are denested, provision could also be made for adjustment in the other direction to accommodate different configurations of trays. However the opening may be dimensioned to accept trays of all standard widths in the one direction and be adjustable as described to accommodate trays of different lengths.

Various other modifications may be made without departing from the invention. For example the drive arrangement may differ from that described and shown and also the denesting components may be different from those described and shown.

Claims

Claims:

1. Apparatus for denesting articles with peripheral flanges from a nested arrangement thereof, the apparatus comprising means for supporting a plurality of nested articles, means for separating an outermost one of the articles from the others while maintaining support of said others, and means for effecting alternate function ing of the supporting means and the separating means, whereby to successively separate outermost ones of the articles from the nested arrangement.

2. Apparatus according to Claim 1, wherein the supporting means comprises first rotatable components at spaced locations, each said first rotatable component being profiled to alternately present a surface in alignment with the flanges of the nested articles and remove a surface from alignment.

3. Apparatus according to Claim 2, wherein the separating means comprises second rotatable components at spaced locations, each said second rotatable component being profiled to alternately present a surface in alignment with the flanges of the nested articles and remove a surface from alignment, the or each surface having cam means adapted to co-act with the article flanges and thereby effect separation of an outermost article from the other nested articles.

4. Apparatus according to Claim 3, wherein each of said first rotatable components is integrally formed as a pair with a respective one of said second rotatable components.

5. Apparatus according to Claim 4, wherein each integral pair of components has respective edges in parallel spaced planes and angularly spaced.

6. Apparatus according to Claim 3, wherein each of said first rotatable components forms a pair with a respective one of said second rotatable components, the components of the pair being separately formed.

7. Apparatus according to Claim 6, wherein each pair of components has respective edges in parallel spaced planes and angularly spaced.

8. Apparatus according to Claim 6 or 7, wherein the rotatable components of each pair are angularly adjustable relative to one another.

9. Apparatus according to any of Claims 6 to 8, wherein the rotatable components of each pair are spaced from one another, and the spacing is adjustable.

10. Apparatus according to any of Claims 4 to 9, wherein the means for effecting alternate functioning comprises a drive for imparting rotation to each pair of components.

11. Apparatus according to Claim 10, wherein each pair of components is mounted for rotation with a pulley and the drive is in the form of an endless belt which wraps around each of the pulleys and around a plurality of further pulleys, one of which is operatively connected with the drive.

12. Apparatus according to Claim 11, wherein the pulleys associated with the respective pairs of components are movably located whereby to adjust the spacing between the pairs of components.

13. A method of denesting articles with peripheral flanges from a nested arrangement thereof, the method including the steps of supporting a plurality of nested articles, separating an outermost one of the articles from the others while maintaining support of said others, and alternately effecting the supporting and separating, whereby to successively separate outermost ones of the articles from the nested arrangement.

14. Apparatus for denesting articles substantially as hereinbefore described with reference to the accompany ing drawings.

15. A method of denesting articles substantially as hereinbefore described with reference to the accompanying drawings.

16. Any novel subject matter or combination including novel subject matter disclosed in the foregoing Specification or Claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding Claims.