US 3253762 A
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Description (OCR text may contain errors)
May 31, 1966 T. N. GAUNT 3,253,762
' TRAYS, CONTAINERS AND THE LIKE Filed March 25, 1964 2 Sheets-Sheet l INVE NTOR: Thomas Norman Gaunt His Alf'y May 31, 1966 T. N. GAUNT TRAYS, CONTAINERS AND THE LIKE 2 Sheets-Sheet 2 Filed March 23, 1964 INVENTOR: Thomas Norman Gaunt wmwax His A rf'v United States Patent 3,253,762 TRAYS, CONTAINERS AND THE LIKE Thomas Norman Gaunt, Leeds, England, assignor to Illinois Tool Works Inc., Chicago, 11]., a corporation of Delaware Filed Mar. 23, 1964, Ser. No. 354,514 Claims priority, application Great Britain, Mar. 25, 1963, 11,640/ 63 2 Claims. (Cl. 2292.5)
Plastic containers of relatively thin wall thickness, manufactured from such materials as polystyrene, P.V.C., polyethylene, polypropylene, etc, are finding extensive use on account of their relative inexpensiveness and other desirable characteristics.
For certain purposes, such packages, however, are unsatisfactory owing to their inherent repellancy to many liquids, which come in contact with such plastic surfaces.
It is one of the principal advantages of this present invention to provide a plastic container capable of absorbing or retaining, within its side walls and/or base, liquids which frequently separate from foodstuffs being packaged. In many cases, particularly in the packing of fresh meat, this is especially desirable to keep the product in good condition and to improve its appearance and sales appeal. Further advantages are to produce a package of improved heat insulation characteristics, air circulation within the package, and protective cushioning to prevent the occurrence of physical damage to the packaged articles in transit. A further advantage is the possibility of decreasing the moisture vapour and gas permeability characteristics of the package to desirable and controllable limits dependent upon the thinning, stretching or orientation of the material during forming. Many attempts to overcome these problems have been proposed, such as the provision of ribs in the base and side walls of packages, or by the lamination together of plastic sheets in a corrugated form before forming, and retaining some of these corrugations after forming. None of these proposals have been entirely satisfactory.
This present invention overcomes previous disadvantages through the provision of a plurality of capillary recesses, capable of holding quantities of liquids out of contact with the product being packaged even when the container is inverted. The capillaries may be arranged to minimise the surface contact of such products as meat with the plastic, and to allow the free passage of air beneath the product and to provide cushioning. The capillary recesses may be moulded or formed in the base and/ or side walls of the container by suction or pressure moulding techniques, using heated plastic sheet together with suitable moulds. The recesses may be either vertical or inclined to the plane of the base of side walls of the package. The capillary recesses may be of circular, square, polygonal or of other suitable cross-sectional shape having adequate ratio of depth to diameter or Width in order to alford sufficient capillary attraction and the total surface area covered by the said recesses should preferably be relatively greater than the area of the material forming the peaks on which peaks is intended to rest the product or article to be packaged.
The said recesses are preferably tapered in a manner whereby they are narrower at their closed ends.
The side walls, which as previously stated, may include capillary recesses, also preferably include ribs which not only serve to strengthen or reinforce the containers but also act as distance-pieces for packaged products, permit circulation of air and provide chambers for condensation of moisture.
In order that the invention may be fully and clearly Patented May 31, 1966 comprehended the same will now be described with reference to the accompanying drawings, in which:
FIGURE 1 is a top plan view of a tray constructed according to one embodiment of the invention;
FIGURE 2 is a cross-sectional view of the tray shown in FIGURE 1;
FIGURE 3 is a plan view, drawn to larger scale, of a portion of the base of the tray illustrated in FIGURES 1 and 2;
FIGURE 4 is a cross-sectional view along the line 4-4 in FIGURE 3.
It will be observed on referring to the drawings that the container or tray is of dished form of rectangular shape having a base or bottom and sides inclined outwardly at an angle to the base. The angle of inclination of the Walls is preferably about 45.
The top of the walls is outwardly disposed to form a perimetral flange 1 preferably furnished with an inverted perimetral channel or groove 2 which serves to stabilize the article.
Each Wall embraces a plurality of hollow ribs 3 of substantially semicircular cross-section, each rib merging at its upper end into the corresponding wall while the opposite end merges into the base of the article at a predetermined distance from the juncture of the wall with the base.
It must be understood that the ribs 3 may be of any other suitable cross-sectional shape and may be formed upon only two of the opposing Walls.
Formed in the container base are a plurality of capillary recesses, cavities or cells 4 comprising substantially hemispherical depressions Whose upper ends are tapered or slightly rounded to provide a reticulated or approximately honeycomb patterned series of boundary Walls 5 forming a plurality of peaks 6. These peaks minimize the areas of contact of the package or container with the contained product or article and can allow circulation of air. Furthermore, such a construction imparts a stiffening effect to the container to an extent which makes possible the successful use of relatively thin sheet material.
Circulation of air as stated becomes possible although the boundary walls 5 separate the several recesses or cells 4 because the peaks 6 on the walls ensure air spaces or connections between the recesses. In other words,.the said recesses, boundary walls and peaks are somewhat like a multiplicity of inverted pyramids or frusto pyramids arranged with one corner uppermost, on which corners rest any object being packed.
A container or tray constructed according to the invention is readily obtained by utilizing a pressure or vacuum forming machine or mould composed of expanded metal produced by stretching perforated sheet metal in two directions in well known manner. Production moulds may be made by casting in metal or other suitable materials reproductions having the same or similar reticulated effects.
It has also been found that vertical or angled capillaries of considerable depth may readily be formed from a heat resistant rubber mould which may be reinforced with fibre and which can give rise to particularly deep capillaries capable of ready withdrawal from themould.
The liquid absorption or retaining characteristics of the tray may, if desired, be varied in dilferent parts of the tray by varying the depth and/ or dimensions of the depressions or the number of cavities or cells per unit of area. Trays may contain moulded partitions (FIGURE 2), which may or may not themselves contain capillaries, to separate different products contained in the same tray.
The cavities may be moulded for example to the extent of from 4 to 64 per square inch. The number of cavities moulded may conveniently be used for accurately and progressively decreasing the gas and moisture vapour permeability of a sheet material or package to render it more ideally suitable for packaging particular commodities. Plastic materials used may, if desired, be laminated and particularly interesting effects are obtained by laminating an expanded sheet material such as expanded polystyrene sheet to unexpanded polystyrene sheet, and forming packages from such laminates.
Trays may be overwrapped, closed with heat sealable or friction fitting lids, and the lidding material may itself, if desired, contain suitable absorbing or retaining cavities.
If desirable the base of the container may slope in any direction to cause any great local concentrates to flow and be retained. The outer edge of the base of the container may, in such a case, remain flat while varying the depths of the capillaries or alternatively, by moulding feet to the package to allow it to rest fiat.
As a further example, a small percentage of the cavities may be opened towards their base, which will allow liquid exceeding the height of the capillary to escape. The open base of the capillary may be less deep than the closed capillaries to allow the container to stand readily and allow the liquid to escape. Such packages can find use for horticultural purposes. If desired, packages containing such perforated cavities may be supported in a further cardboard or plastic container.
1. A container made of plastic material having a bottom wall and a side wall which extends upwardly therefrom to an open mouth, at least one of said bottom and side walls in at least a portion thereof provided with a plurality of discrete, closely spaced recesses capable of receiving and holding quantities of liquid out of contact with products in said container, the material portion adjacent the upper end of each recess being interconnected reticulated partitions strengthening the area in which said recesses are provided, each said material portion having peak portions between which air circulation is permitted adjacent recesses, said peak portions minimizing areas of contact between the container and its contents.
2. The container set forth in claim 1 wherein the material portion surrounding each of said recesses extends outwardly of the plane of the container wall in which said recesses are formed to aiford cushioning to products received by the container.
References Cited by the Examiner UNITED STATES PATENTS 2,073,498 3/1937 Seez u 229 X 2,077,757 4/1937 Jackson 22072 X 2,088,074 7/1937 Voight 99425 2,321,676 6/1943 Hennessy 99425 2,492,053 12/1949 Mendel et a1 99425 X 2,802,411 8/1957 Riener 2293.5 X 2,918,379 12/1959 Lurie.
3,026,209 3/ 1962 Niblack et al 99174 3,151,799 10/1964 Engles et al 2292.5 3,155,303 11/1964 Fenkel 22987 3,156,402 11/1964 Dupuis 22930 JOSEPH R. LECLAIR, Primary Examiner.
FRANKLIN T. GARRETT, D. T. MOORHEAD,