GB2216881A - An egg tray - Google Patents

Abstract

An egg tray has posts 12 and cells contoured to accommodate Jumbo size eggs. Viewed in vertical section, the contiguous surfaces at the post cell define an upper portion of outwardly curved configuration (relative to a cell centre line) and a lower portion of inwardly curved configuration (relative thereto). Viewed in plan the curvature at the post top is outwardly directed relative to the centre line whereas a projection extending upwardly from the base has an inwardly directed curvature. Such tray can be used for collecting eggs of all sizes including Jumbo size. <IMAGE>

Description

An Egg Tray This invention relates to an egg tray and more especially an egg tray which is stackable such that superposed trays form complete protective envelopes for the eggs therebetween.

For efficiency in the collection of eggs at the farm, the eggs are largely ungraded and a tray is used to accommodate most sizes of egg for transit to the egg grading and packaging station at which eggs are transferred to trays or cartons all containing a given grade of egg. Extra large eggs may be graded by hand, which is labour intensive, because the conventional trays do not safely accommodate the extra large eggs.

Egg trays for collection purposes may thus contain the usual range of egg grades from 2 (large) to 5 (small).

Nowadays there are more and more extra-large eggs (grade 1 and larger so called Jumbo eggs'). Conventional trays easily accommodate and protect the grade 2 eggs, but frequently problems arise with the extra-large eggs above grade 1 size eggs which are more valuable at the point of sale. If packed in conventional trays many of the extra large eggs are damaged in transit due to load transmission in the stack. Superposed trays may transmit loads through the trays. Conventional design has allowed such loads to be transmitted to the eggs themselves in the case that the extra large egg is in load bearing contact with the underside of that tray which is superposed on its own tray. Breakages result in loss of the eggs.They also result in a shortened tray life in that a spoiled tray cannot be re-used again and the expected number of times the tray is re-used is reduced. Both these factors are expensive losses for the egg producers and/or egg packers.

The present invention seeks to provide embodiments of an egg tray which avoid the aforesaid disadvantages.

According to one aspect of the present invention there is provided an egg 'tray which is stackable such that juxtaposed trays form protective envelopes therebetween for extra large eggs, said tray comprising cells and posts disposed such that when one such tray is superposed upon another such tray with the bases of cells of the upper tray in register with the posts of the lower tray then pockets are defined thereby which pockets form said protective envelopes, wherein at a post contiguous surfaces of a said cell and that post are contoured along first upper and second lower portions of oppositely directed curvature as viewed in section through that cell on a plane through that post and a diametrically opposed post of the same cell, said first upper portion of said contiguous surfaces being outwardly curved relative to a centre line through said cell.

In an embodiment at a post the contiguous surfaces of a said cell and that post are contoured as seen in plan, whereby at the post the edge of the post top and the post surface depending therefrom have a curvature which extends radially outwardly relative to a centre line of the cell, said outwardly directed curvature continuing downwardly through the length of the post surface towards the cell base and into an upper part of the contiguous cell surface, said cell surface also being formed with a protrusion which internally of the cell extends upwardly from the cell base towards the cell surface with the outwardly directed curvature, the protrusion having an inwardly directed curvature relative to the cell centre line, said protrusion being formed of material of substantially uniform thickness whereby the protrusion contour is apparent in the external surface of the cell.

In a preferred embodiment as viewed in said vertical section through that cell, or part of said upper portion has an internal curvature defined by a radius A, said radius A corresponding to the radius of curvature of a contiguous part (when in situ) of a notional egg of 85.4 grams weight at the surface of contact thereof with a seat therefor defined by said part.

In a preferred embodiment as viewed in said vertical section through that cell, a part of said lower portion has an external curvature defined by a radius B, said radius corresponding to the radius of curvature of the contiguous part (when in situ) of a notional egg of 85.4 grams weight and a clearance dimension Y.

The centres for drawing the radii A, B may be determined in accordance with adjustment of the height at which the said notional egg is to sit above the cell base.

The dimension Y may be between 5 and 15% of the length of said radius B, and is preferably 9%.

In a preferred embodiment as viewed in said vertical section, there is a curvilinear transition between said upper and lower portions of oppositely directed curvature.

In a preferred embodiment the mid-point of said transition is a height above said base which is measured as being between 40 to 45 per cent of the vertical distance between the cell base and the post top, preferably 42%.

In a preferred embodiment as viewed in vertical section, the contour of said upper portion contiguous with said post top and the contour of said lower portion contiguous with said base are linear. Advantageously, said linear surfaces are inclined at an angle of between 12 to 18 degrees to the vertical centre line for de-nesting purposes, preferably 15 degrees.

Preferred embodiments are formed from moulded fibrous material of which the best known and most widely used for egg tray manufacture is moulded pulp.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows schematically a partial perspective view of part of an egg tray; Fig. 2 shows schematically further detail of an elementary part of Fig. 1; Figs. 3A to 3C show sections taken on lines A-A, B-B and C-C of Fig. 2 but only in respect of the cell/post wall to illustrate the wall section and curvature; Fig. 4 shows a schematic view through a cell and posts as viewed in section through that cell on a plane through diametrically opposed posts; and Fig. 5 shows in plan a schematic diagram of a tray.

In the drawings an egg tray 10 having posts 20 and cells 30 is shown schematically in Fig. 5. This tray 10, like conventional compact trays, is stackable with another like tray such that juxtaposed trays (see Fig. 4) form protective envelopes for eggs therebetween. The overall dimensions of the tray in terms of its sides (as seen in plan in Fig. 5) are typically 309 x 309 mm. The height of the tray is typically 50.88 mm. The latter dimension is the distance between the lower and upper surfaces of the tray as defined by the underside 11 (or external surface) of the base of a cell 30 and the top 12 (or upper surface) of a post 30. The distance between the centres of adjacent cells 30 is typically 49.5 cm.

This type of compact tray 10 usually has the cells 30 extending to a general plane defined by strengthening ribs 13 between the posts 20 (see Fig. 1). Side walls 14 on one pair of lateral sides extend almost to the level of the tops 12 of posts 20 and bear laterally outwardly extending flanges 15. As schematically indicated in Fig. 5 partial posts 21 merge into the walls 14 in conventional manner. Likewise, partial cells 31 extend along the other pair of sides 16 which are open above the level of flanges 17 and which are closed below the level of flanges 17. Flanges 17 are at a distance above the underside 11 similar to the distance of flanges 15 below the top 12. As is well known in the art, such trays 10 may be nested when an upper tray is arranged above a lower tray with the side walls 14 of both trays aligned in parallel.Likewise they may be stacked (as schematically illustrated in Fig. 4) when the upper tray is arranged with its side walls 14 at right angles to the side walls 14 of the tray below and when the underside 11 of the bases of cells 30 of the upper tray 10 are in register with the tops 12 of the posts 20 of the lower tray 10. The aforegoing describes the characteristics of compact trays known in the art in which ungraded eggs have been packed. The tray 10 of the preferred embodiment described herein takes these characteristics as the egg packaging industry makes these requirements in order that new trays will be compatible with old trays in terms of their handling characteristics, particularly where automated handling is concerned. Similarly, although not shown in the drawings, it will be appreciated that the trays 10 can be provided with de-nesting features.

The further description herein will concentrate on the characteristics of the tray of this embodiment which enable the tray 10 to accommodate the larger Jumbo eggs in advantageous manner. It should be remembered that the primary purpose of the tray 10 is for use when eggs are collected at an egg farm and thereafter transportation to a packing station. The person collecting eggs will load ungraded eggs into the tray.

It will not be necessary to remove Jumbo eggs, but it is advantageous to place them such that, if adjacent, they are diagonally aligned as in cells 30a, 30c of Fig. 5 rather than laterally aligned as in cells 30a, 30b of Fig. 5.

The schematic perspective view of Fig. 1 which is taken from above and towards one side shows only part of a tray 10. A cell 30D is bound by four posts 20 which extend above the general plane defined by the strengthening ribs 13. Each post 20 terminates at its top 12 which can be seen in plan to have a substantially diamond-shaped configuration, but one in which the edges 22 are curvilinear. Each post 20 has side walls 23 depending from a respective edge 22; the side walls 23D being associated with cell 30D and contiguous with the wall portions thereof (as shown in Fig. 2). The configuration of side walls 23D will be further described. The four edges 22 of a post 20 and the surfaces 23 are similar whereby the individual posts 20 have symmetry. It will be seen that surfaces 24 extend at each corner to ribs 13.Similarly neighbouring cells 30 are similar and, at the level of the plane defined by ribs 13, the cells 30 are of circular configuration as seen in plan. Subject to the comments below, the cells 30 may be said to have a generally frusto-conical configuration.

The sketch of Fig. 1 does not attempt to show the internal detail of cell 30. For this purpose reference is made to Fig. 2 which is a further sketch showing a perspective view of part of a cell 30 and one post 20, with the objective of illustrating (in conjunction with Figs. 3A to 3C) the contour of the cell 30 and post 20 relative to a centre line upstanding from the cell base 18D. In the context of Fig. 2 the cell 30 has a wall portion 32D contiguous with the wall portion 23D of the post 20. Together wall portions 23D and 32D define a pocket surface. Viewed radially of the cell axis this surface has a contour which changes from the cell base 18D to the post top 12D. Firstly within the cell 30, at the lower most edge 33D of surface 32D, it will be seen that the curvature of edge 32D is oppositely directed relative to the edge 22D of the post surface 23D.Edge 22D defines the junction between surface 23D and post top 12D. In effect, whilst base 18D has a similar configuration to top 12D it has been rotated through 90 degrees relative thereto. This has the further characteristic that, when one tray is stacked upon another the contacting base 18 and top 12 when in register have a matching configuration. A portion of surface 32D forms what may be termed a protrusion 34D extending into the cell 30. This protrusion 34D is formed of the tray material of substantially uniform thickness (as seen in the sectional view of Fig. 3C) in order that the external surface corresponding to surface 32D (at the region of protrusion 34D) has a complimentary configuration. The term internal surface is applied to designate the surface 32D within the cell 30 shown in Fig. 2. The term external surface will be understood accordingly.Curvature of protrusion 33D is maintained as the protrusion 33D rises upwards from its lower edge 33D, but its width reduces until it terminates as shown in Fig. 2. In contrast the surface 23D of the post 12D has an upper edge 22D having a curvature directed outwardly relative to the central axis of cell 30D. The material of wall portion 23D is also formed of tray material of substantially uniform thickness and the sense of the curvature is maintained as the surface 23D progress downwardly towards cell 30D.

This is illustrated by sectional views of that wall in Figs. 3A and 3B. The section of Fig. 3B is taken at the level of ribs 13 and thus the junction between post surface 23D and cell surface 32D. Cell surface 32D continues with this curvature down to the top of protrusion 34D as seen in Fig. 2. The cell wall portions 35D and 36D (adjacent the cell wall portion 32D) are configured such that other than the protrusion 34D and the aforesaid contour of the portion 32D above the protrusion 34D, the cell 30 exhibits a frusto-conical configuration which extends to those parts of wall portion 32D laterally of the protrusion 34D.

Further contouring of the post walls and cell walls will now be described with reference to Fig. 4 in which elements are shown in section of an uppermost tray 10A superimposed on a lower most tray lOB with a pair of Jumbo size (for illustrative purposes on 85.4 gram) eggs 41, 42 located so as to illustrate the cell capacity.

This Fig. 4 is again shown schematically so the material of tray lOB is given a thickness, whereas that of tray lOB is shown by a single line. It should also be noted that in practice there would be no gap between the egg 41 and tray 20B at the regions 43, 44 which indicate the region of contact of egg 41 and tray lOB. The sketch of Fig. 4 can be regarded as being taken through the post 22D on the line D-D of Fig. 1. This line D-D may be regarded as a section through cell 30D on a plane through the post 22D and a diametrically opposed post 22A (Fig. 1), if one nominates the tray lOB as the tray of Fig. 1 and regards tray l0A as a similar tray stacked thereon.In Fig. 4 it will be seen that the post walls 23D, 23A define the upper part of an egg receiving pocket in tray lOB; this pocket is completed by the tray l0A above which is referenced to indicate like parts. Fig. 4 clearly illustrates that juxtaposed trays l0A, lOB form protective envelopes therebetween for the extra large eggs exemplified by egg 41. It can be seen that trays lOA, lOB each comprise cells 30 and posts 20 disposed such that when one such tray lOA is superposed upon another such tray lOB with cell bases 18 of tray l0A in register with post tops 12 of tray lOB then pockets are defined thereby which form protective envelopes for extra large (or Jumbo) eggs. It will be seen that this is achieved by the contouring shown in Fig. 4.For descriptive purposes, it will be seen at a post (with top 12D) the contiguous surfaces 23D and 32D of cell 30D and that post are contoured along a first upper portion and a second lower portion with oppositely directed curvature. The curvature of the first upper portion 45 is outwardly directed relative to a centre line through the base 18D of cell 30, whereas the curvature of the second lower portion 46 is inwardly directed relative to the centre line. The contiguous surface/walls 23D and 32D form a smooth transition between the curved portions 45, 46. Where surfaces/walls 23D, 32D extend to their junctions with the post top 12D and the cell base 18D respectively their configurations are substantially linear and at an angle of 15 degrees to a line normal to those surfaces 12D and 18D for de-nesting purposes. The internal curvature of upper portion 45 in the region of contact with the egg 41 is described by a radius A which corresponds to the radius of curvature (at the egg surface of contact) of a model Jumbo egg 41 of 85.4 grams weight. Such models are familiar to egg tray designers and whilst the characteristics thereof represent a generally assumed configuration, these characteristics are well established. Similarly, the external curvature of lower portion 46 in the region in which egg 42 is adjacent thereto is described by a radius B. This radius B is designed to exceed the radius of curvature of a similar model egg 42 at that location with the addition of a dimension Y which is the inbuilt (or designed in) clearance between egg 42 and the external surface of lower wall portion 46.

Dimension Y plus the thickness of the wall 23 thereat gives dimension X which is the spacing between the two eggs.

It will be noted that there is some latitude in the position at which the tray designer locates the centres for drawing the radii A, B in accordance with adjustment of the height at which the eggs 41, 42 sit in their cells 30 above a respective cell base 18.

This embodiment of egg tray is moulded fr-om pulp. In this embodiment the surface of ribs 13 is spaced equi-distantly from the top surface 12 and bottom surface 11. The transition position between the upper curved portion 45 and the lower curved portion 46 is at a location which is measured to be about 42% (preferably between 40 and 45%) ofthe distance between surfaces 11 and 12. This dimension is variable according to the aforementioned locations of the centres on which the radii A, B are drawn. Exemplary values of the radii A, B are 37mm, 41mm, the distance X is 5.3mm and the thickness of the wall 1.6mm (whereby dimension Y is 3.7mm). The greater the dimension Y that can be accommodated within the design parameters, the greater the protection the tray provides against the transmission of loads between eggs of successive trays in a stack.

Claims (13)

CLAIMS:

1. An egg tray which is stackable such that juxtaposed trays form protective envelopes therebetween for extra large eggs, said tray comprising cells and posts disposed such that when one such tray is superposed upon another such tray with the bases of cells of the upper tray in register with the posts of the lower tray then pockets are defined thereby which pockets form said protective envelopes, and wherein at a post the contiguous surfaces of a said cell and that post are contoured along first upper and second lower portions of oppositely directed curvature as viewed in vertical section through that cell on a plane through that post and a diametrically opposed post of the same cell, said first upper portion of said contiguous surfaces being outwardly curved relative to a centre line through said cell.

2. An egg tray as claimed in Claim 1, wherein at a post the contiguous surfaces of a said cell and that post are contoured as seen in plan, whereby at the post the edge of the post top and the post surface depending therefrom have a curvature which extends radially outwardly relative to a centre line of the cell, said outwardly directed curvature continuing downwardly through the length of the post surface towards the cell base and into an upper part of the contiguous cell surface, said cell surface also being formed with a protrusion which internally of the cell extends upwardly from the cell base towards the cell surface with the outwardly directed curvature, the protrusion having an inwardly directed curvature relative to the cell centre line, said protrusion being formed of material of substantially uniform thickness whereby the protrusion contour is apparent in the external surface of the cell.

3. An egg tray as claimed in Claim 1 or Claim 2, wherein, as viewed in said vertical section through that cell, or part of said upper portion has an internal curvature defined by a radius A, said radius A corresponding to the radius of curvature of a contiguous part (when in situ) of a notional egg of 85.4 grams weight at the surface of contact thereof with a seat therefor defined by said part.

4. An egg tray as claimed in any one of Claims 1 to 3, wherein, as viewed in said vertical section through that cell, a part of said lower portion has an external curvature defined by a radius B, said radius corresponding to the radius of curvature of the contiguous part (when in situ) of a notional egg of 85.4 grams weight and a clearance dimension Y.

5. An egg tray as claimed in Claim 4, wherein the centres for drawing the radii A, B are determined in accordance with adjustment of the height at which the said notional egg is to sit above the cell base.

6. An egg tray as claimed in Claim 4, wherein the dimension Y is between 5 and 15% of the length of said radius B.

7. An egg tray as claimed in any one of Claims 1 to 6, wherein, as viewed in said vertical section, there is a curvilinear transition between said upper and lower portions of oppositely directed curvature.

8. An egg tray as claimed in Claim 7, wherein the mid-point of said transition is a height above said base which is measured as being between 40 to 45 per cent of the vertical distance between the cell base and the post top.

9. An egg tray as claimed in Claim 7 or Claim 8 wherein, as viewed in vertical section, the contour of said upper portion contiguous with said post top and the contour of said lower portion contiguous with said base are linear.

10. An egg tray as claimed in Claim 9, wherein said linear surfaces are inclined at an angle of between 12 to 18 degrees to the vertical centre line for denesting purposes.

11. An egg tray as claimed in any one of Claims 1 to 10, wherein said tray is formed from moulded fibrous material.

12. An egg tray as claimed in Claim 11, wherein said fibrous material is pulp.

13. An egg tray which is stackable such that juxtaposed trays form protective envelopes therebetween for extra large eggs, arranged, constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.