Egg tray

Abstract: In an egg tray (1) constituting a thin-walled body of rigid fibre-pulp material in which are formed a plurality of pockets (2) and posts (3), each said pocket being surrounded by a small number of said posts (3) and comprising an egg-supporting region (6,8a,8b) adapted to support an egg (not shown), the main new feature is that said egg-supporting region (6,8a,8b) constitutes a continuous part of a substantially ellipsoidal surface approximating the ellipsoidal or quasi-ellipsoidal surface of the pointed part of an egg of a size within the egg-size interval for which the egg tray (1) is intended to be used. With this arrangement, the eggs are supported gently and steadily in a predictable orientation, the weight of each egg being distributed in the ellipsoidal supporting region (6,8a,8b).

Description: TECHNICAL FIELD The present invention relates to an egg tray of the kind set forth in the preamble of claim 1, which is known from WO-A-94 13 558. BACKGROUND ART Egg trays of the kind referred to above normally comprise thirty pockets arranged in five rows of six pockets each. They are normally used by the egg producers for packaging eggs to be delivered to e.g. a wholesale distribution site comprising a packaging station. The egg producers fill the egg trays manually or by using suitable machinery, while at the packaging station, the eggs are removed mechanically in machines normally using arrays of suction cups, in the example referred to arranged in five rows of six cups each, for transferring the eggs from the egg trays supplied by the producer to a quality and grading control stage and from there to a final packaging stage, in which the eggs are placed in e.g. smaller egg cartons suitable for sale in retail shops. In previously known egg trays of the kind referred to initially, the egg-supporting surface consists of a ring-shaped abutment region. The narrow ring-shaped abutment region puts a relatively high contact pressure on the egg shell, especially when the egg size of the egg does not correspond exactly to the size of the pocket, thus creating a risk of breakage. This problem is not made less serious by the fact that a new size classification for eggs has been introduced. According to this new classification, an egg tray of a given size is expected to accommodate eggs within a size interval that is greater than was the case with the previous classification. When using the previously known egg trays, this may result in that many eggs, especially the smallest ones within the class concerned, will not come to rest steadily in the egg-supporting surface. This risk of instability is particularly important when at the production site manually or mechanically placing the eggs in the egg trays, as it is important, not only with regard to placing another egg tray on top of one having just been filled, that the eggs having been deposited in the pockets automatically assume a steady and predictable orientation, but also with regard to the mechanized packaging subsequently taking place at the packaging station, in which the eggs are lifted from the trays by means of suction cups as described in the preceding paragraph. Various attempts have been made to solve these problems, such as by increasing the size of the various abutment regions, but these attempts have only met with limited success, presumably because the abutment region has not been appreciably extended, so that the risk of breakage or instability has not been reduced to any considerable extent. DISCLOSURE OF THE INVENTION It is the object of the present invention to provide an egg tray of the kind referred to initially, with which the disadvantages referred to above are considerably reduced, and this object is achieved with an egg tray of said kind, according to the invention also having the features set forth in the characterizing clause of claim 1. In this construction, there is only one single abutment region constituted by the continuous ellipsoidal or quasi-ellipsoidal surface, with upper and/or lower protuberances, on which the eggs when deposited will come to rest in stable and predictable orientations, with their weight more or less evenly distributed over the entire surface, thus avoiding both local stress concentrations and instability, as well as ensuring a good engagement with the suction cups used to remove the eggs from the trays. Advantageous embodiments of the egg tray acccording to the invention, the effects of which - beyond what is obvious - are explained in the following detailed part of the present description, are set forth in claims 2-7. BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed part of the present description, the invention will be explained in more detail with reference to the exemplary embodiment of an egg tray shown in the drawings, of which Figure 1 is a plan view showing a corner region of the egg tray, Figure 2 is a sectional view showing four egg trays stacked on one another, of which the lower three contain eggs, the section being a diagonal one taken along lines corresponding to the line B-B in Figure 1, and Figure 3 is a perspective view showing part of an egg tray cut along a diagonal line to show details of the pockets and posts forming the tray. DESCRIPTION OF THE PREFERRED EMBODIMENT The egg trays 1 shown in the drawing consist in a manner known per se of a rigid, thin-walled body, made by aspirating an aqueous fibre pulp onto a perforated mould and then consolidating and drying the body thus formed. Each tray comprises, likewise in a manner known per se , a plurality of pockets 2 and posts 3 arranged in a regular pattern, that is normally orthogonal, i.e. having pockets and posts arranged in rows crossing each other at right angles, but other patterns, such as a hexagonal "honeycomb" pattern, may also be used. In the embodiment shown, the normal orthogonal arrangement is used, so that each pocket is surrounded by four posts 3, and each post 3 is - except at the edges - surrounded by four pockets 2. One important feature of the egg tray 1 is the shape of the egg-supporting surface 6,8a,8b shown stippled in one of the pockets 2 in Figure 3. In order to support an egg 5 (not shown in this particular pocket 2) as gently and steadily as possible, this surface 6,8a,8b is a part of a circular ellipsoid, i.e. a surface described by an ellipse rotating about one of its axes, or a surface closely approximating such an ellipsoid. Such a surface has proved to be a close approximation to the shape of the "pointed" end of a hen's egg. The egg-supporting surface 6,8a,8b consists of three parts, i.e. a continuous zone 6 extending from a first level I at a distance of approximately 22 mm above the level of the pocket bottom 7 to a second level II at a distance of approximately 25 mm above said bottom 7, a number of, in the present case four, upper protuberances or tongues 8a extending upwardly on the sides of the respective posts 3 in continuation of the zone 6 from the second level II to a third level III at a distance of approximately 33 mm from the bottom 7, and an equal number of, in the present case four, lower protuberances or tongues 8b extending downwardly on the internal sides of the lower part 11 of the respective pocket 2 to a fourth level IV at a distance of approximately 20 mm from the bottom 7 It should be noted that said approximate dimensions may vary depending on the size of eggs within the class, with which the egg tray 1 is to be used. The continuous zone 6, together with the lower tongues 8b, has proved to provide reliable support in the downward direction, i.e. against the force of gravity and dynamic forces created, when at the production site, e.g. a poultry farm, the egg tray concerned is being filled with eggs, either manually or using a suitable machine, so that they automatically assume a stable upright position centered in the respective pockets 2. Similarly, when the egg tray is placed on a table in a not too gentle manner, the upper tongues 8a will keep the eggs steady against forces directed sideways, such as dynamic forces created e.g. when the egg tray is pushed sliding on a shelf against a wall. This means that the eggs, when arriving at the packaging station in e.g. a wholesale distribution site, will remain in the correct orientation in the egg trays, thus ensuring a safe encounter with the suction cups used in this station for transferring the eggs to e.g. smaller egg cartons for distribution to retail shops. At the same time, the open spaces between the upper tongues 8a, i.e. between the respective posts 3, and above the continuous zone 6, the upper limit of which is said second level II, allow visual access to a large proportion of the surface of the eggs when viewed at an acute angle from above. At the third level III, the upper tongues 8a pass smoothly into substantially conical surface segments 9. These act as lead-in surfaces when placing the eggs in the pockets, thus reducing the risk of breakage by collision with the tops 10 of the respective posts 3. Another important feature of the egg tray 1 is the shape of the lower part 11 of each pocket 2. In the embodiment shown, this lower part 11 is of generally square cross section, symmetrical about the vertical axis of the continuous zone 6, and extends from the pocket bottom 7 at a slightly obtuse angle, flaring upwardly and outwardly to merge into the lower tongues 8b at the fourth level IV and into the continuous zone 6 at the first level I. In fact, it is the external shape of the lower part 11 that is important in the present connection. As may be seen from Figure 2, cf. especially the right-hand egg 5 in the middle row, the lower part 11 of a pocket in an egg tray 1 above the one, in which this particular egg 5 rests, lies very close to a part of the upper half of the egg, thus improving safety. On the other hand, sufficient clearance must be provided to prevent the lower part 11 from pressing locally on an egg in a pocket in a lower tray. The lower part 11 could also be rounded or round, provided that its external shape fulfils the function explained above. As always when egg trays containing eggs are to be stacked, the trays must be properly aligned in order to avoid damage to the eggs. One way of achieving this is to provide downwardly protruding projections 12 adapted to fit into holes 13 in the tops 10 of the posts 3 of the next egg tray below. Before use, egg trays of this type are normally closely stacked or "nested", the pockets and posts of each tray fitting closely into the pockets and posts of the tray lying below and above, respectively. To make it easy to remove single trays from the stack, egg trays are normally provided with some kind of "de-nesting" feature, and in the egg tray 1 shown, crescent-shaped denesting ribs 14 extend between the various posts 3 mid-way between the egg-supporting surfaces 6,8a,8b in respective pockets 2. The ribs 14 are not hollow - persons skilled in the art of moulding fibre-pulp articles will know how to achieve this - and will constitute spacers keeping the egg trays in a stack at a distance from each other, thus preventing too close mutual engagement of the relatively rough surfaces on the posts and in the pockets. LIST OF PARTS 1 egg tray 2 pocket 3 post 5 egg 6 continuous zone 7 pocket bottom 8a upper protuberance/tongue 8b lower protuberance/tongue 9 conical surface segment 10 top 11 lower part (of 2) 12 projection 13 hole 14 denesting rib I first level II second level III third level IV fourth level

Claims: Egg tray (1) constituting a thin-walled body of rigid fibre-pulp material in which are formed a plurality of pockets (2) provided with a bottom and posts (3), each said pocket being surrounded by a small number of said posts (3) and comprising an egg-supporting surface (6,8a,8b) adapted to support an egg (5) when placed therein, whereby said egg-supporting surface (6,8a,8b) constitutes a continuous part of a substantially ellipsoidal surface approximating the ellipsoidal or quasi-ellipsoidal surface of the pointed part of an egg of a size within the egg-size interval for which the egg tray (1) is intended to be used, characterized in that said egg-supporting surface (6,8a,8b) comprises a continuous circular zone (6) and upper protuberances (8a) extending upwardly from said continuous zone (6) on the adjacent sides of said posts (3), and/or that at its lower boundary (I), said continuous circular zone (6) passes smoothly, wholly or partly through lower protuberances (8b) being part of said substantially ellipsoidal surface into a flared surface (11) extending downwardly. Egg tray (1) according to claim 1, characterized in that said upper protuberances (8a) at a distance from the tops (10) of said posts (3) pass smoothly into conical surface segments (9) extending substantially up to said tops (10). Egg tray (1) according to claim 1 or 2, characterized in that said lower protuberances (8b) pass into a flared surface (11) extending downwardly to a substantially flat bottom (7) adapted to rest on one of said tops (10) when the egg tray (1) is placed on top of another egg tray of the same kind, such as in a stack, the outside of the part comprising said flared surface (11) being shaped and placed so as in parts to be close to an upper surface part of an egg (5) placed in a pocket in a subjacent egg tray of the same kind. Egg tray (1) according to claim 1 or 2, characterized by crescent-shaped denesting ribs (14) extending from each post (3) to the next mid-way between said egg-supporting surfaces (6,8a,8b) in pockets (2) on each side of said denesting ribs (14). Egg tray (1) according to any one or any of the claims 2-4, characterized in that the level (II) of the upper limit of said continuous zone (6) as well as of the upper edge of said denesting ribs (14), if present, is so low as to allow a substantial part of the lower surface of an egg (5) placed in the pocket (2) to be visible when viewing the egg tray (1) at an acute angle from above. Egg tray (1) according to any one or any of the claims 1-4, characterized by a) holes (13) through or recesses in said tops (10), and b) projections (12) in said bottoms (7) adapted to engage said holes (13) or recesses in a subjacent egg tray of the same kind. Egg tray (1) according to any one or any of the claims 1-6, characterized in that said egg-supporting region is so shaped and dimensioned relative to the shapes and dimensions of eggs of the species and size intervals, with which the egg trays (1) are to be used, that eggs having been placed manually or mechanically in the pockets (2) will automatically assume a centered upright position.

Inventors: DALL IWER, DALL, IWER
Applicants: HARTMANN AS BRDR, BRODRENE HARTMANN A/S
Application year: 1997
Main classification: B65D85
IPC codes: B65D85