AU2012324468A1

AU2012324468A1 - Stackable trays

Info

Publication number: AU2012324468A1
Application number: AU2012324468A
Authority: AU
Inventors: Ronald George Starnes; Ritchie John Williams
Original assignee: Alto Packaging Ltd
Current assignee: Alto Packaging Ltd
Priority date: 2011-10-19
Filing date: 2012-10-19
Publication date: 2014-05-01
Also published as: WO2013057698A1

Abstract

A foam tray adapted to be nestable into tray stacks when unfilled as a storage space and transportation cost saving means. The tray having improved stack nestable features including that the outward splay of at least the inside surface of the wall is less in a lower region than in an upper region of the wall(s), and/ or wherein a lower region of the wall is thinner and/ or more dense than the upper region of the wall.

Description

WO 2013/057698 PCT/IB2012/055711 Stackable Trays FIELD OF THE INVENTION The present invention relates to stackable trays. In particular one aspect of the invention relates to stackable trays for packing produce. BACKGROUND TO THE INVENTION Trays (which are open top containers of any form and profile, but usually having a base (profiled or not) and peripheral walls (profiled or not)) are adapted to be nestable into tray stacks when unfilled as a storage space and transportation cost saving. They are adapted when filled with a product then to be sealed by a foil or film wrap or by a foil or film or other material lid sealed to the rim of the peripheral wall. Typically trays are formed of a plastics material. Where the plastics material is unfoamed a wall thickness typically of less than 1mm (e.g. about 0.6mm) can be used to provide a robust tray which, as a consequence of an outward flange (curled or otherwise) as its rim, has sufficient wall and rim flexibility and strength to resist damaging deformations in use. Such trays with non-foamed thin plastic walls are able to nest more deeply for a given wall splay angle than are trays of foam plastics material. Typically a tray of a foam plastics material (whether open or closed cell foam) requires a greater splay angle to nest to the same extent as well as greater wall thickness (typically 3 to 4 mm) to resist damaging deformations. Mere substitution of a foam tray with one of unfoamed plastics material has hitherto lead either a greater stack height (when empty) of the nested foam trays, when compared to the unfoamed plastics tray, or alternatively has lead to a significantly reduced foot print internally of the tray for product placement for a similar sized tray owing to the wall splay angles required for nesting. The present invention has as an objective provision of a foam plastics tray with sufficient foam thickness where required yet which does not significantly reduce base foot print and/or require excessive splay of its wall. An alternative object is to provide a useful choice. We believe a tray formed from a web of foamed plastics material to have a base and a peripheral wall (irrespective of profiling features that still lend themselves to nesting and/or product placement and irrespective of rim features such as flange) can provide an improved stack height performance compared to traditional foamed plastic trays. This is by providing a WO 2013/057698 PCT/IB2012/055711 -2 greater area for product placement and similar stacking heights. For a similarly sized base, the outwards splay of at least the inside surface of the peripheral wall if less in a lower region than in upper region of the wall, and the lower region of the wall if thinner and more dense than is the material of the upper region of the wall, will result in such enhanced nesting performance. It is trays of that kind that the present invention is directed as an aspect of the invention. SUMMARY OF THE INVENTION In another aspect the invention is a nestable tray or container formed from a web of foamed plastics material to have a base and a peripheral wall; characterised in that the outward splay of at least the inside surface of the wall is less in a lower region than in an upper region of the wall(s), and further characterised in that said lower region of the wall is thinner and more dense than said upper region of the wall. The upper region need not extend to the rim (flanged or not) but can do so in some embodiments. Preferably there is a transition from the lower region to the upper region and that transition can be over a zone or at a particular peripheral height. Preferably the wall has a profiled rim e.g. defining an outwardly directed flange. Preferably at least the lower region of the wall rises from a base region of a foam substantially of the thickness of said web prior to the forming of the tray. Preferably a bulbous or other profile features are emergent from or from adjacent the base periphery and extend upwardly to or into part of the upper region. Preferably the thinner material is caused by mated moulds acting on a foam web from which the tray is mould formed. In another aspect the invention is a nestable tray thermoformed from a foam web or foam sheet to have a base, and a peripheral wall; wherein, when considered in horizontal section, a lower region of the peripheral wall, over at least part of it full perimeter, undulates thereby defining profile features; and wherein the density of the material is greater, or varies to include zones greater, in density than in the foam web or foam sheet and in density than in the base and/or upper region of the peripheral wall.

WO 2013/057698 PCT/IB2012/055711 -3 Preferably the lower region is steeper generally than said upper region. Preferably the lower region generally flares outwardly of the base but the upper region generally flares more. In another aspect the invention is a nestable tray of a foam where opposed wall regions from the base of a peripheral wall (or, if of square or rectangular base, distinct wall expanses to rounded, truncated or like corner transitions) have, when considered in horizontal section, a meandering, undulating or other strength conferring profile in a lower region emergent from the base and of thinner and/or denser material than the thicker and/or less dense upper region. Preferably the tray has been formed using mated moulds acting on a foam web or foam sheet. Preferably the part line of the mated moulds is in the profile of the lower region (preferably closer to the thicker and/or less dense upper region than to a preferred thicker and/or less dense base. In another aspect the invention is a tray of any of the kinds typified generally by trays substantially as herein described where the tray has been moulded from a foam web and the thickness variations are of a kind substantially as herein contemplated with or without reference to any one or more of the accompanying drawings and/or the splay of at least inside surfaces or regions of the wall as substantially as herein described with or without reference to any one or more of the accompanying drawings. In a further aspect the invention consists in a nestable tray or container ("tray") having a base and a peripheral wall; wherein the tray is of a material that has been thermoformed from a foam web; and wherein the base and regions of its peripheral wall commencing a distance above the base are of material of similar thicknesses yet a transition zone from base to the similar thickness zone in the wall involves a thinner and more dense form of the material, that denser form resulting from pressure during the thermoforming process. Preferably said transition zone is steeper generally, or at least its inner surface is steeper generally, than said similar thickness zone of the peripheral wall. In a further aspect the invention consists in a tray able to nest within a like tray a predetermined distance as a consequence of stack indexing features, the tray being thermoformed from a foam web of constant thickness yet providing in the thermoformed tray a zone transitioning from the base into some higher region of the wall, whether profiled or not, to enhance strength and/or base footprint.

WO 2013/057698 PCT/IB2012/055711 -4 Preferably the transition zone is thinner, is more dense, is steeper on at least in its inner surface, or any combination thereof In yet another aspect the invention is stack indexed and nested trays, each identical and having been thermoformed from a foam material, and characterised in that the more deeply nested intrusion of each tray is of a peripheral wall, or includes peripheral wall regions, pressure moulded to be thinner at least one or more of (i) thinner, (ii) denser and/or (iii) steeper than a less deeply nested or unnested part of the peripheral wall or peripheral wall regions. Preferably the more deeply nested intrusion, at least in part, is profiled by undulations in horizontal section. In a further aspect the invention consists in a method of providing a foam tray of a kind that will nest in a reduced height compared to traditional foam tray. In another aspect the invention is a method of manufacturing foam trays which comprises or includes providing a web of thermoformable foam material, and match moulding trays from or in, yet detachable from, the web; the match moulding defining nestable trays with a pressed zone as a transition from a foam material base into an peripheral upper wall region. Preferably the transition is profiled (e.g. substantially as herein described). Optionally in any of the embodiments the base from below can be generally concave with preferably a substantially corresponding convexity from above. Yet preferably despite this rounding is substantially able to achieve the nestability wanted (see for example Figures 23 onwards). Examples of materials include of a suitable foam sheet or foam web, and, if a web, can still be at a post extrusion elevated temperature to allow mated mould forming include polystyrene, polypropylene, polyethylene, PET, PLA, biopolymer material. The term "comprising" as used in this specification and claims means "consisting at least in part of'. When interpreting each statement in this specification and claims that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner. As used herein the term "and/or" means "and" or "or", or both.

WO 2013/057698 PCT/IB2012/055711 -5 As used herein the term "(s)" following a noun includes, as might be appropriate, the singular or plural forms of that noun. A preferred form of the present invention will now be described with reference to the accompany drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top perspective view of a first embodiment, this embodiment having a substantially rectangular footprint, but with rounding at the comers, the tray having outward bulges as profiled features in the longitudinal walls at their lower region, the rim having an outwardly extending flange with a downturn to avoid film puncture, and the corner regions having a corner or truncated corner nest supporting outstand to both confer rigidity and to be supported on the corresponding underling shoulder of a like tray when nested, Figure 2 is a view of the tray of Figure 1 from a bottom perspective view, Figure 3 is a top plan view of the tray of Figures 1 and 2 showing axis AA and BB, Figure 4A is the section AA of Figure 3, Figure 4B is the section AA of two trays in a nested condition, showing the angles alpha (a) and beta (s), Figure 5A is the section BB of Figure 3, Figure 5B is the section AA of two trays in a nested condition, showing preferably similar angles alpha (a) and beta (P), Figure 6 is a top perspective view of a different embodiment, this embodiment not having the bulges or profile features of the lower region of the embodiment of Figures 1 to 5, Figure 7 is a bottom perspective view of the tray of Figure 6, Figure 8 is a top plan view of the embodiment of Figure 6 and 7, Figure 9 is the section AA of the tray of Figure 8, Figure 10 is the section BB of the tray of Figure 8, Figure 11 is a top perspective view of a third and preferred embodiment, Figure 12 is a perspective view from below of the embodiment of Figure 11, Figure 13 is a plan view of the embodiment of Figures 11 and 12, Figure 14 is a bottom view of the tray of Figures 11 to 13, Figure 15 is an end view in elevation of the embodiment of Figures 11 to 14, WO 2013/057698 PCT/IB2012/055711 -6 Figure 16 is a front or side elevational view of the embodiment of Figures 11 to 15, Figure 17 is the section AA of Figure 13 in elevation, Figure 18 is the section BB of Figure 13 in elevation, Figure 19 is the horizontal section at CC of Figure 16 in plan, Figure 20 is the horizontal section DD of Figure 16 in plan, Figure 21 on the section AA of Figure 13 in elevation shows the assembly stack detail of two identical trays. Figure 22 shows a sketch view from below of a version of a container that can have wall thickness variation as suggested by the present invention, but have more of a rib-like form in that diminishing ribs extend upwardly from the general region of the base, such non rounding of the transition from base into the wall not being preferred (but not being ruled out) where there is a profiled arrangement on the walls upwardly of the base, Figure 23 is a top perspective view of another preferred embodiment, Figure 24 is a bottom perspective view of the embodiment of Figure 23, Figure 25 is a top plan view of the embodiment of Figures 23 and 24, Figure 26 is a front view of the embodiment of Figures 23 to 25, Figure 27 is the section A-A of the embodiment of Figures 23 to 26, Figure 28 is the section B-B of the embodiment of Figures of 23 to 27, Figure 29 is the section at C-C of the embodiment of Figures 23 to 28, Figure 30 is the section D-D of the embodiment of Figures 23 to 29, Figure 31 shows the section A-A (a region only) of each of two such trays of Figures 23 to 30 to demonstrate stack detail, Figure 32 is a top perspective view of another preferred embodiment, Figure 33 is a bottom perspective view of the embodiment of Figure 32, Figure 34 is a top plan view of the embodiment of Figures 32 and 34, Figure 35 is a front view of the embodiment of Figures 32 to 34, Figure 36 is the section A-A of the embodiment of Figures 32 to 35, Figure 37 is the section B-B of the embodiment of Figures of 32 to 36, Figure 38 is the section at C-C of the embodiment of Figures 32 to 37, Figure 39 is the section D-D of the embodiment of Figures 32 to 38, Figure 40 shows the section A-A (a region only) of each of two such trays of Figures 32 to 39 to demonstrate stack detail, Figure 41 is a top perspective view of another preferred embodiment, Figure 42 is a bottom perspective view of the embodiment of Figure 41, WO 2013/057698 PCT/IB2012/055711 -7 Figure 43 is a top plan view of the embodiment of Figures 41 and 42, Figure 44 is a front view of the embodiment of Figures 41 to 43, Figure 45 is the section A-A of the embodiment of Figures 41 to 44, Figure 46 is the section B-B of the embodiment of Figures of 41 to 45, Figure 47 is the section at C-C of the embodiment of Figures 41 to 46, Figure 48 is the section D-D of the embodiment of Figures 41 to 47, Figure 49 shows the section A-A (a region only) of each of two such trays of Figures 41 to 48 to demonstrate stack detail, DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In some preferred forms of the present invention substantially general outward flare angles alpha (a) and beta (P) are provided respectively for the inside surface of the zones of the opposed pairs of walls of a rectangular based tray. In the embodiment of Figures 1 to 5B, the trays have a base 1, a lower region 2 and an upper region 3. In the case of the sections shown in Figures 4A and 5A, the similarly provided foam thickness of regions 1 and 3 more or less accord to the foam web stock used for the preferred mate moulding or other thermoforming, although it may be slightly thinner. It is the zone 2 that is thinner and more dense. The zone 2 is also preferably steeper (i.e. less splay on at least its inside surface and preferably also its outside surface) in order to facilitate nesting in the manner shown in Figures 4B and 5B. Over the compressed foam material zone of 2, between the arrowheads of 4 and 5, there are the characteristics preferred for the region previously defined as the lower region. The outward splay of at least the inside surface, and preferably both surfaces, over that lower region side zone is less than in the upper region 5 above. In order to enhance footprint of the base internally, and particularly where items such as but not limited to sausages may be the items to be loaded, the lower layer having less space is better accommodated by the outstands 6. These outstands can be seen in Figure 1 on the longitudinal side. No such outstands are provided on the ends but Figure 11 later shows an embodiment fully surrounded by such features. Stack indexing supporting features 7 (i.e. downwardly facing shoulders of an outstand) are shown at each of the rounded comers below the outstanding and downturned WO 2013/057698 PCT/IB2012/055711 -8 flange 8 of the rim. This shoulder 7 can be nest supported onto the reverse side (i.e. as an upwardly facing shoulder). Other features are shown. The embodiment of Figures 6 to 10 shows a tray more or less to a form as previously described but without such bulbous features arising from preferably meandering or undulating or otherwise profiling intermittently or otherwise in horizontal section. Typically whether a form as shown in Figures 1 to 5B, 6 to 10, or 11 to 20, a preferred angle of the lower region alpha (a) can be approximately half that of angle beta (p). By way of example only, the respective angles can be about 11.5 degrees and about 23 degrees respectively for a rectangular tray of silhouette in plan of about 185mm x 228mm and, of overall height 57mm and of base foam thickness of about 5.5mm or less. Such an arrangement as shown in Figures 1 to 4B will allow for example approximately 1.4kg of sausages to be laid as two layers in the tray (a seven sausages bottom layer and a nine sausage top layer). The internal footprint for such a 1.4kg sausage tray is improved by approximately 13%. A preferred embodiment is as shown in Figures 11 through 20 where there is shown a generally rectangular base 9, opposed longer walls or wall regions 10, and less lengthy end wall opposed regions 11. In each instance there is a transition through a preferred identical corner form 12 which truncates the corner right from the limit of the rectangular base form up into the peripheral flange 13 via the outstands 14. The general rounding, when viewed in plan, of the corners 12 is carried down preferably to the base to facilitate nesting i.e. there is no bulbous profile outwardly of the generally corner region 12 that might interfere with nesting. On each wall region of the peripheral wall, whether regions 10 or 11, there are plural outstands 15 each of which includes a part line 16 of the preferred mated moulds. These bulbous outstands 15 are seen as upwardly extending scallop-like female cavities 17 from within but nonetheless, when viewed in the horizontal sections of CC of Figure 16 shown in Figure 19, can be shown as an undulating region for each of the opposed walls or wall regions of substantially constant thickness. These regions 18 shown in Figure 19 are more dense and are thinner than the thickness shown as 19 in Figure 20 being a horizontal section DD of the embodiment of Figure 16. It can be seen nonetheless that in each of the horizontal sections of Figure 19 and 20, at least some of the corner region 20 and all of the corner region 21 is of the thickness of the upper wall regions depicted as 19.

WO 2013/057698 PCT/IB2012/055711 -9 Three other embodiments are shown with the sectional views as defined by common sections A-A, B-B, C-C, and D-D for each of the three embodiments (i.e. of Figures 23 to 31, Figures 32 to 40 and Figures 41 to 49) showing an upwardly domed base region and/or curved walls. By way of example, each of the views of Figures 27 and 28 (but this is so for the other sections A-A and B-B referred to in respect of the later embodiments), has a thick foam base that is upwardly domed having a generally convex top side and a generally concave under side region 22. However there is sufficient rounding both internally and externally to allow the stacking shown. The transition externally rounds at 23 steeply to assist in narrowing at 24. Likewise the interior at 25. Notwithstanding the use of a foam the stackability is similar to that of a non-foam tray of equal size and capacity. Examples of materials include of a suitable foam sheet or foam web, and, if a web, can still be at a post extrusion elevated temperature to allow mated mould forming include polystyrene, polypropylene, polyethylene, PET, PLA, biopolymer material.

Claims

1. A nestable tray or container formed from a web of foamed plastics material to have a base and a peripheral wall; characterised in that the outward splay of at least the inside surface of the wall is less in a lower region than in an upper region of the wall(s), and further characterised in that said lower region of the wall is thinner and more dense than said upper region of the wall.

2. A nestable tray or container as claimed in claim 1, wherein the tray or container includes an upper rim and the upper region does not extend to the upper rim.

3. A nestable tray or container as claimed in claim 1 or claim 2, wherein the upper rim is flanged.

4. A nestable tray or container as claimed in any one of the preceding claims, wherein there is a transition from the lower region to the upper region and that transition can be over a zone or at a particular peripheral height.

5. A nestable tray or container as claimed in any one of the preceding claims, wherein at least the lower region of the wall rises from a base region substantially of the thickness of said web prior to the forming of the tray.

6. A nestable tray or container as claimed in any one of the preceding claims, wherein bulbous or other profile features are emergent from or from adjacent the base periphery and extend upwardly to or into part of the upper region.

7. A nestable tray or container as claimed in any one of the preceding claims, wherein the thinner material is caused by mated moulds acting on a foam web from which the tray is is mould formed.

8. A nestable tray thermoformed from a foam web or foam sheet to comprise: a base, and a peripheral wall; WO 2013/057698 PCT/IB2012/055711 - 11 wherein, when considered in horizontal section, a lower region of the peripheral wall, over at least part of it full perimeter, undulates thereby defining profile features; and wherein the density of the material is greater, or varies to include zones greater in density than in the foam web or foam sheet and greater in density than in the base and/or upper region of the peripheral wall.

9. A nestable tray or container as claimed in claim 8, wherein the lower region is steeper generally than said upper region.

10. A nestable tray or container as claimed in claim 8 or claim 9, wherein the lower region generally flares outwardly of the base but the upper region generally flares more.

11. A nestable tray thermoformed from a foam web or foam sheet to comprise: a base, and a peripheral wall wherein opposed wall regions from the base of the peripheral wall include distinct wall expanses to rounded, truncated or like corner transitions having, when considered in horizontal section, a meandering, undulating or other strength conferring profile in a lower region emergent from the base and of thinner and/or denser material than a thicker and/or less dense upper region.

12. A nestable tray as claimed in claim 11, wherein the tray has been formed using mated moulds acting on a foam web or foam sheet.

13. A nestable tray as claimed in claim 12, wherein the part line of the mated moulds is in the profile of the lower region (preferably closer to the thicker and/or less dense upper region than to a preferred thicker and/or less dense base.

14. A tray of any of the kinds typified generally by trays substantially as herein described where the tray has been moulded from a foam web and the thickness variations are of a kind substantially as herein contemplated with or without reference to any one or more of the accompanying drawings and/or the splay of at least inside surfaces or regions of the wall as substantially as herein described with or without reference to any one or more of the accompanying drawings. WO 2013/057698 PCT/IB2012/055711 - 12

15. A nestable tray or container ("tray") having a base and a peripheral wall, wherein the tray is of a material that has been thermoformed from a foam web; and wherein the base and regions of its peripheral wall commencing a distance above the base are of material of similar thicknesses yet a transition zone from base to the similar thickness zone in the wall involves a thinner and more dense form of the material, that denser form resulting from pressure during the thermoforming process.

16. A nestable tray asclaimed in claim 15, wherein said transition zone is steeper generally, or at least its inner surface is steeper generally, than said similar thickness zone of the peripheral wall.

17. A tray able to nest within a like tray a predetermined distance as a consequence of stack indexing features, the tray being thermoformed from a foam web of constant thickness yet providing in the thermoformed tray a zone transitioning from a base into a higher region of the wall, whether profiled or not, to enhance strength and/or base footprint.

18. A tray as claimed in claim 17, wherein the transition zone is thinner, is more dense, is steeper on at least in its inner surface, or any combination thereof

19. An assembly of nested trays, each identical and having been thermoformed from a foam material, and characterised in that the more deeply nested intrusion of each tray is of a peripheral wall, or includes peripheral wall regions, pressure moulded to be at least one or more of: (i) thinner, than a less deeply nested or unnested part of the peripheral wall or peripheral wall regions, (ii) denser than a less deeply nested or unnested part of the peripheral wall or peripheral wall regions, (iii) steeper than a less deeply nested or unnested part of the peripheral wall or peripheral wall regions.

20. An assembly of nested trays as claimed in claim 19, wherein the more deeply nested intrusion, at least in part, is profiled by undulations in horizontal section. WO 2013/057698 PCT/IB2012/055711 - 13

21. A method of providing a foam tray of a kind that will nest in a reduced height compared to traditional foam tray.

22. A method of manufacturing foam trays which comprises or includes providing a web of thermoformable foam material, and match moulding trays from or in, yet detachable from, the web; the match moulding defining nestable trays with a pressed zone as a transition from a foam material base into an peripheral upper wall region.

23. A method of manufacturing foam trays as claimed in claim 22, wherein the transition is profiled.

24. A tray as claimed in any one or more of claims 1 to 20, wherein the base (when viewed from below) is generally concave.

25. A tray as claimed in claim 24, wherein the base is substantially correspondingly convex (when viewed from above).