Lid Arrangement Having Stacking Options

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to packages for packaging and dispensing of products, in particular powdered products such as infant nutrition or milk formula. The invention relates in particular to a lid structure for such packages having a re-closable lid and means for stacking such packages. The invention further relates to a stackable set of such packages.

Description of the Related Art

Containers for packaging and dispensing of powdered products such as infant nutrition or milk formula are known from the prior art. These containers are usually made of metal or plastic material in a form of a can with a re-closable top lid. The containers typically have cylindrical shape with a circular base. Consequently, such containers are rather difficult to stack on a pallet or on a shelf as they cannot be tightly packed due to their shape.

Stack displays of such containers in shops, for example, may be particularly difficult to assemble. This is especially the case with stacking pyramids wherein the containers are positioned such that a container stacked in a layer above is placed on top of a multiple containers of a layer beneath. However, due to the circular base of these containers, gaps are formed in between adjacent containers forming the layer. When assembling a next layer of containers on top of the previous one, a caution must be exercised as an incorrectly positioned container in the layer may cause collapse of the whole assembly. Even after the assembly, the stack display may easily collapse if, for example, a customer tries to remove a container from the assembly that is supporting one or more other containers stacked on top of it. It is also desirable that stacked contains are facing in the same direction. This is particularly the case for cylindrical containers that are nevertheless intended to have a given orientation e.g. due to the presence of branding.

To facilitate stacking, some containers are provided with stacking means. U.S. Pat. No. 5,535,910 discloses a refuse container and corresponding lid for storing and transporting goods, wherein the lid is slightly domed and provided with raised rim portion and the bottom of the container is shaped to correspond to the lid to allow for vertical stacking and to limit the lateral motion of the stacked containers. However, one such container only allows for stacking containers directly on top of each other. However, resulting stacking assembly can sustain only a few stacked containers placed on top of each other, before collapsing. Furthermore, such containers cannot be placed over multiple containers and as such are not suitable for assembling stacking displays and pyramids.

U.S. Pat. No. 5,392,945 discloses a container which includes a bottom having a pair of circular recesses and a lid having a pair of circular projections in alignment with the circular recesses so that the container may stack with similar containers. However, such a solution is not particularly useful for powdered products as the product can be stuck between the recesses, impeding the complete discharge of the product. Nor is this solution suitable for containers having a circular base due to the gaps formed in between the adjacent containers upon arranging them in a layer. WO 2007/142522 discloses a non-circular container having stacking ridges on its lid, while US 2020/255191 describes a circular container having a lid that can be stacked with other lids.

An improved lid would be desirable that facilitates both vertical stacking and pyramid stacking of the respective containers.

BRIEF SUMMARY OF THE INVENTION

Therefore, according to a first aspect of the invention, there is provided a lid structure according to claim 1 that at least partially overcomes shortcomings of the prior art. The lid structure for a container comprises an annular collar for attachment to the container and has an opening for providing access to an interior of the container. The lid structure further comprises a lid for closing the opening, wherein the lid has an outer periphery and an upper surface with a circumferential ridge located near to but spaced from the outer periphery, whereby a further container having a base diameter can stack at an outside of the circumferential ridge. The circumferential ridge further has at least two interruptions dividing the circumferential ridge into at least two ridge portions whereby at least two further containers having the same base diameter can stack partially on the lid.

The container comprises a body with a base. Preferably, the body is cylindrical with the circular base at a first end and an open mouth at a second end of the body, bounding the interior of the container. The base may be bound by a lower rim and the base diameter my correspond to an inner diameter of the lower rim. In a preferred embodiment, a diameter of the mouth may be equal to the base diameter. The lower rim may extend downwardly from the base by a lower rim height. The annular collar may be connected to the body around the mouth such that the opening of the lid structure is aligned with the mouth in order to provide access to the interior of the container. An inner diameter of the annular collar may correspond to the diameter of the mouth in order to easily connect the lid structure to the container. The body and the annular collar may be connected by a connection means in a form of mating protrusions, snap-fit locks, an adhesive, tight-fit connections, and/or similar means configured to form a stable connection between the lid structure and the container.

The circumferential ridge may have an inner ridge diameter and an outer ridge diameter. In an embodiment, the outer ridge diameter may correspond to the base diameter. In such an embodiment, a further container having the same base diameter may be vertically stacked on top of the lid structure as the sliding of the further container from the lid structure is prevented by the circumferential ridge. The circumferential ridge locks the further container in place and suppresses any lateral movement of the further container. Advantageously, the lid structure according to the present invention enables formation of stable vertically stacked assemblies, for example, when packing the containers into a box, onto a shelf or a pellet for storing, selling, and/or transporting purposes. Additionally, the circumferential ridge provides a visual identification of an area for placement of the further container. A worker in a packaging line can, thus, quickly identify this area and place the further container when packing containers increasing the overall speed of the packaging process.

The ridge elevates from the upper lid surface by a circumferential ridge height. In an embodiment, the circumferential ridge height may be in a range between 0.5 mm and 5 mm, preferably around 1 mm. The skilled person understands that the circumferential ridge may have other circumferential ridge heights and the upper limit of the range is determined by the lower rim height. Additionally, a thickness of the circumferential ridge may be around 1 mm. However, other thicknesses are envisaged as well. There are no structural constrictions that would limit the thickness of the circumferential ridge. Nonetheless, the circumferential ridge according to this embodiment is preferred as it is discrete and does not influence the aesthetics of the lid. It is easy to manufacture with a minimal additional material used. Nevertheless, the circumferential ridge is strong enough to hold in place at least one further container filled with a product stacked on top of it.

Preferably, the circumferential ridge is an integral part of the lid. The circumferential ridge may be made from the same material as the lid structure, for example, plastic material.

The lid structure has an opened configuration and a closed configuration. In the closed configuration, the lid is placed over the opening and blocks access to the interior of the container connected to the lid structure. In the opened configuration, the lid is displaced from the opening allowing access to the interior.

In an embodiment, the outer periphery of the lid may have a diameter that corresponds to an outer diameter of the annular collar. Additionally, the lid and the annular collar may be arranged to form an insect-tight seal upon closing the lid structure.

In a further embodiment, the lid and the annular collar may be hingedly connected together, preferably via a living hinge. The hinged connection provides a pivotable motion of the lid about the living hinge allowing full access to the opening and the interior of the container. Alternatively, the lid and the annular collar may be connected via a screw-threaded connection, a tight-fit connection, or similar.

In an embodiment, the lid structure may comprise a closure element engaged between the lid and the annular collar. The closure element may be arranged to allow for a switching between the opened and the closed configuration only upon engaging the closure element. The closure element may be in a form of a snap-fit joint comprising a male portion and a female portion configured to interlock, wherein the male portion may be connected to the annular collar and the female portion may be connected to the lid. The closure element may further comprise a finger engaging section comprising the female portion and configured to release the snap-fit joint upon applying pressure onto the finger engaging section. The closure element may be an integral part of the lid structure. The closure element may additionally comprise a tamper evident closure element configured to block functioning of the closure element and prevent opening of the lid structure. The tamper evident closure element may be connected to the lid structure by a breaking connection comprising at least one breaking point, wherein the breaking connection is configured to break in order to disconnect the tamper evident closure element from the lid structure prior to first opening of the lid structure.

The lid may be substantially circular and the interruptions may be arranged radially around a central axis of the lid. The interruptions may be oriented radially, or substantially radially, to the lid. The circumferential ridge may comprise any number of interruptions such as two interruptions, three interruptions, four interruptions and so on. In an embodiment, one of the at least two interruptions is located around the closure element. The absence of the ridge around the closure element and more particularly, around the finger engaging section, is desired as the circumferential ridge may cause a user's discomfort when the user presses onto the circumferential ridge in order to open the lid structure.

The interruptions are arranged to facilitate pyramidal stacking of the containers having the lid structure according to the present invention. Stacking pyramids are formed of vertically stacked container layers, wherein the containers in each layer are arranged in a side-by-side configuration. Each upper layer container belonging to a vertically higher layer is contemporaneously stacked over a plurality of lower layer containers lying directly under the upper layer. In the 2D stacking pyramids, each layer comprises a row of side-by-side arranged containers, wherein each upper layer container is contemporaneously stacked over two lower layer containers. Such stacking configurations are frequently used for shop displays. However, they may also be preferred for other stacking situations comprising large number of container layers. Vertically stacked containers, formed by stacking the upper layer container fully on top of the container laying directly under it, are easier to assemble but such assemblies are not particularly stable and collapse with only a few containers vertically stacked on top of each other. The stacking pyramids, on the other hand, are more difficult to assemble but allow forming more container layers before collapsing.

The interruptions are configured to divide the circumferential ridge of the lid into ridge portions, wherein each ridge portion is configured to fit within the lower rim of a further container partially stacked on top of the lid in order to lock the further container in place when pyramidally stacked. In other words, to pyramidally stack the containers having the lid structures according to the present invention, the lower rim of the upper layer container may be placed over a plurality of ridge portions belonging to a plurality of lower layer containers. A number of ridge portions may correspond to a number of the lower layer containers being used to stack the upper layer container. For example, the upper layer container may be stacked on top of three lower layer containers by placing the lower rim of the upper layer container over three ridge portions belonging to lid structures of the three lower layer containers. In this example, the circumferential edge may have three interruptions and three ridge portions. In another example, the upper layer container may be stacked on top of four lower layer containers by placing the lower rim of the upper layer container over four ridge portions belonging to lid structures of the four lower layer containers. In this example, the circumferential ridge has four interruptions and four ridge portions. In the same example, the upper layer container may be 2D pyramidally stacked on top of two lower layer containers by placing the lower rim of the upper layer container over two ridge portions of each of the lid structures of the lower layer containers. Advantageously, the lid structure according to the present invention facilitates pyramidal stacking of the containers, simplifies assembly of stack displays, and packing and storing of the containers on pallets and/or shelfs.

A length of the ridge portion is defined as a total length of the ridge portion measured between distal ends of the ridge portion. If the ridge portion is a curve, the ridge portion is an arc length. In an embodiment, the lid structure comprises the ridge portions, wherein the length of each ridge portion is configured such that the distal ends of the ridge portion abut the lower rim of the further container upon partially stacking the further container on top of the lid structure. In this manner, there is no or almost no free-play space between the ridge portion and the lower rim when the further container is pyramidally stacked resulting in a stable assembly with very limited or without lateral movement.

In a preferred embodiment, the circumferential ridge has exactly two interruptions dividing the circumferential ridge into two ridge portions. This embodiment is particularly suitable for forming 2D stacking assemblies. Additionally, the lengths of the two ridge portions may be equal and correspond to a third of a base circumference of the further container. This length is chosen based on the geometries of the bases and allows stable stacking of the further container on top of two lower layer containers without formation of a significant free-play space.

The annular collar may comprise a first collar end and a second collar end. The lid may be hingely connected to the annular collar at the first collar end. In an embodiment, the annual collar may comprise a fixation skirt extending from the second collar end. The fixation skirt may be in a form of an inwardly extending inner ring configured to form a snap-fit connection with an outwardly protruding upper rim of the container. The fixation skirt prevents removal of the lid structure from the container without damaging the fixation skirt and protects the content of the container from tampering with.

In an embodiment, a lower lid surface comprises an upwardly extending rim elevating therefrom and configured to form a seal with an inner ring of the annular collar upon closing the lid structure. The inner ring may have an inwardly extending wall comprising a wide ring end and a narrow ring end. A circumference of a narrow ring end may correspond to a circumference of the upwardly extending rim. Additionally, the upwardly extending rim may be configured to pass through the wide ring end and form the seal with the narrow ring end.

In an embodiment, the outer periphery comprises a rounded top edge whereby an annular collar of a further lid structure can be stacked. Advantageously, a stacking assembly of the lid structures according to the present invention may be formed using the rounded top edge when, for example, the lid structures are packed together for storing, shipment, or in a production line before attaching the lid structures to the containers. Optionally, the fixation skirt of the further lid structure may be used to grip the rounded edge in order to provide an additional support when stacking the lid structures and to allow more lid structures to be stacked before collapse of the assembly.

In an embodiment, the base diameter may be in a range between 100 mm and 150 mm, preferably around 125 mm and may correspond to the outer ridge diameter. The diameter of the outer periphery may be in a range between 105 mm and 155 mm, preferably around 130 mm, and may correspond to the outer diameter of the annular collar.

The lower lid surface may comprise a scoop holder and optionally, the scoop holder may be an integral part of the lid. The scoop holder may be in a form of at least one clamping element configured to hold a scoop attached to the lid.

According to a second aspect of the present invention there is provided a package, comprising a lid structure according to the first aspect of the present invention applied to a container. The container has a circumferential sidewall, extending from a mouth to a base and the lid structure is attached to the container by engagement of the annular collar with the mouth.

The base has the base diameter and the base may be bound by the lower rim. The diameter of the mouth may correspond to the diameter of the base.

A volume of the container may be in a range between 0.5 1 and 4 1, preferably between 1 1 and 2.5 1 such as around 2 1.

The container may further comprise an inner flange bounding the mouth and a sealing membrane may be attached to the inner flange in order to sealingly close the package. Despite the presence of the inner flange, the mouth of the container is wide enough to provide for a good reachability to the interior of the container and efficient discharge of a product from the container.

The lid structure may further comprise a scoop holder on a lower surface of the lid. The package may further comprise a scoop, wherein the scoop is placed in a lid space arranged between the lid and the sealing membrane. The scoop may be attached to the scoop holder. The scoop may be used for discharging a product contents from the container. Additionally, the scoop may be protected by a foil wrap placed around the scoop to prevent contamination of the scoop. The scoop has a bowl with a depth in a range between 12 mm and 20 mm, preferably around 16 mm and a volume in a range between 5 ml and 15 ml, preferably between 8 ml and 11.5 ml such as around 10 ml. A height of the lid space may be in a range between 13 mm and 21 mm, preferably around 17 mm

In an embodiment, the container may be a metal can. In a further embodiment, the container may be a three piece can with the base connected to the sidewall at a scam. Optionally, the seam may form a downwardly extending lower rim. The base diameter may be an inner diameter of the lower rim. A height of the lower rim may be in a range between 1 mm and 8 mm, preferably around 5 mm.

The invention also relates to a set of such packages arranged in a stack, wherein each package has a face and adjacent packages in a first row of the stack are held with their faces oriented in alignment with a front side of the stack by engagement of the ridge portions on their respective lids by the base of a package in a second row of the stack that spans the lids of the adjacent packages. As mentioned above, for packages provided with branding or other information or in cases where there is a preferred orientation that is intended, it is desirable that the package facilitates correct placement within a stack. This is particularly important for packages that are generally cylindrical in shape, which nevertheless have a face, namely an intended orientation that should be presented at a front side of the stack. This type of stack may be referred to as a pyramid stack as each row will generally be one package shorter than the row beneath but the term is not intended to be limiting to 2-D or 3-D stacking or to the overall external shape of the stack.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the invention will be appreciated upon reference to the following drawings of a number of exemplary embodiments, in which:

FIG. 1A shows a perspective view of a lid structure according to the present invention with closed lid;

FIG. 1B shows a top view of the lid structure of FIG. 1A;

FIG. 1C shows a perspective view of the lid structure of FIG. 1A with opened lid;

FIG. 1D shows a cross-section through the lid structure of FIG. 1B along a central line C;

FIG. 2 shows a plurality of lid structures of FIG. 1C stacked on top of each other;

FIG. 3A shows a perspective view of a package having a container and the lid structure of FIG. 1A;

FIG. 3B shows a cross-section through the package of FIG. 3B along line IIIB;

FIG. 4A shows in a front view vertical stacking of the packages using the lid structure according to the present invention;

FIG. 4B shows in enlarged view area IVB of FIG. 4A;

FIG. 5A shows in a front view pyramidally stacked packages according to the present invention; and

FIG. 5B shows a schematic view of a pyramidal stacking functionality of the packages according to the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The invention will be explained in more detail below with reference to drawings in which illustrative embodiments thereof are shown. The drawings are intended exclusively for illustrative purposes and not as a restriction of the inventive concept which is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention. The scope of the invention is only limited by the definitions presented in the appended claims.

In the drawings, like numerals designate like elements. Multiple instances of an element may each include separate letters appended to the reference number. For example, two instances of a particular element “48” may be labelled as “48A” and “48B”. The reference number may be used without an appended letters (e.g. “48”) to generally refer to an unspecified instance or to all instances of that element. Further, multiple instances of an embodiment of the present invention plotted in the same figure may include one or more apostrophes appended to the reference number to distinguish them. For example, two instances of a particular embodiment “100” may be labelled as “100′” and “100″” in the same figure. Further, feature belonging to different embodiments may have letters and/or apostrophes. For example, an element “48A′” may belong to the embodiment “100′” while an element “48B″ ” may belong to the embodiment “100″”.

FIGS. 1A and 1B illustrate in a perspective and a top view, respectively, a lid structure 10 according to the present invention. The lid structure 10 includes a lid 12 and an annular collar 14. The lid structure 10 is shown in a closed configuration with the lid 12 placed over the annular collar 14. The lid 12 is connected to the annular collar 14 by a living hinge 24. Opening and closing of the lid structure 10 is performed by employing a closure element 32. The closure element 32 includes a finger engaging section 44 configured for placing a user's finger in order to open the lid 12 and a tamper evident element 37 indicative of the first opening of the lid structure 10. The lid 12 is circular having an upper surface 18 bound by an outer periphery 16. A circumferential ridge 20 elevates from the upper surface 18 and extends parallel to, but at a distance d from, the outer periphery 16. The circumferential ridge 20 is not continuous but has two interruptions 22A, 22B dividing the circumferential ridge 20 into a first ridge portion 20A and a second ridge portion 20B. Arc lengths, or hereafter simply, lengths L of the two ridge portions 20A, 20B are equal. A rear interruption 22A is located in a proximity of the living hinge 24 while a frontal interruption 22B is located around the closure element 32. The lid structure 10 is symmetric with respect to a central line C passing between the live hinge 24 and the closure element 32. Displacing the circumferential ridge 20 from the finger engaging section 44 is preferred to facilitate opening/closing of the lid 12 as the circumferential ridge 20 may cause discomfort to the user when pressed thereon. The interruptions 22A, 22B are used for stacking functionality of the lid structure 10 as it will be evident from the description further below. The circumferential ridge 20 is placed at a distance d from the outer periphery 16 and has a ridge thickness of around 1 mm. The entire lid structure is made of plastic material.

FIGS. 1C and 1D illustrate a perspective view of the lid structure 10 with opened lid 12 and a cross-section through the lid structure 10 along the central line C shown in FIG. 1B, respectively. The annular collar 14 bounds an opening 15 of the lid structure 10. The opening and closing of the lid structure 10 is achieved by connecting the lid periphery 16 to an outer annular collar wall 38 via the living hinge 24 allowing for a pivotal motion of the lid 12 thereabout when opening/closing the opening 15. Additionally, a lid diameter dl is equal to a collar diameter de to tightly close the lid 12 to the annular collar 14 upon closing the lid structure 10. The lid 12 has a downwardly extending rim 26 depending from a lower lid surface 17, which forms a seal with an inner ring 36 of the annular collar 14 on closing. The inner ring 36 is in the form of an inwardly extending wall having a wide ring end 46 and a narrow ring end 48. The inner ring 36 is arranged to allow passage of the downwardly extending rim 26 through the wide ring end 46 and formation of the seal with the narrow ring end 48 upon closing the lid structure 10. The lower lid surface 17 further includes a scoop holder 28 for holding a scoop 30 for dispending of the contents of the container. The scoop 30 has a bowl 31 and a scoop handle 33. The outer annular collar wall 38 has a fixation skirt 39 extending along an opposite end of the annular collar distant to the living hinge 24. Further, the ridge 20 has an inner ridge diameter di and an outer ridge diameter do. The difference between the two diameters is equal to twice the ridge thickness. In the given embodiment, the thickness of the ridge 20 is small and the two diameters are almost equal. Nonetheless, the thickness of the circumferential ridge 20 may be much larger such as 5 mm or even 10 mm. Consequently, the two diameters may differ more. Additionally, a circumferential ridge height h is around 1 mm, but as with the thickness, the circumferential ridge height may be larger in alternative embodiments.

FIG. 2 shows stacking capabilities of the lid structures 10. The figure shows three lid structures 10, 10′, 10″ vertically stacked on top of each other. The outer periphery 16 is in the form of a rounded top edge 42 allowing the outer annular collar wall 38′ of a further lid structure 10′ to be placed over it to form a stack. The outer annular collar wall 38′ is made of elastic material and bends outwardly upon applying a vertical force F in a direction perpendicular to the upper surface 18 forming a grip to the lid 12. The grip is further enhanced by a pleated surface of the fixation skirt 39′. Under the vertical force F, the pleated surface of the fixation skirt 39′ deforms and increases a contact area with the rounded top edge 42 thereby enhancing the grip.

FIGS. 3A and 3B illustrate a package 100 having a container 50 and the lid structure 10 according to the present invention. The container 50 has the form of a can. A sidewall 52 of the container 50 is connected by a longitudinal seam 54 enclosing an interior 56 of the container 50. In this view, for the sake of convenience, the seam 54 is visible at a front of the container 50 but it will be understood that the seam is usually located at the rear side. The container 50 has a base 60 connected to the sidewall 52 by a second seam 58 forming a downwardly extending lower rim 62. The lower rim 62 elevates the base 60 by a lower rim height hr. A base diameter dr is defined across the inside of the lower rim 62. The container 50 further includes an outwardly protruding upper rim 66 and an open mouth 64 located at an opposite end of the container 50 with respect to the base 60. The mouth 64 is bounded by an inner flange 68. The annular collar 14 of the lid structure 10 is placed over the mouth 64 and fixed to the container 50 by a snap-fit connection formed between the fixation skirt 39 and the outwardly protruding upper rim 66. Additionally, the fixation skirt 39 is arranged to prevent removal of the lid structure 10 from the container 50 without damaging the fixation skirt 39 in order to prevent tampering with the product placed within the container 50. Additionally, the narrow ring end 48 of the inner ring 36 is placed over the inner flange 68 to further fix the annular collar 14 to the container 50. The formed snap-fit connection is insect-tight. The package 100 also includes a membrane seal 70 placed over the mouth 64 and connected to the inner flange 68 by an adhesive. The membrane seal 70 prevents degradation of the product placed in the interior 56 due to environmental influences. The scoop 30 is placed within a lid space 72 formed in between the lid 12 and the membrane seal 70. A bowl height hb is chosen to coincide with a lid space height hl for optimal use of the lid space 72 and to maximize use of the interior 56 for the product.

FIG. 4A depicts a vertical stacking of two identical packages 100, 100′. A further package 100′ is stacked on top of the package 100 by placing the lower rim 62′ of the further package 100′ at the outside of the circumferential ridge 20 (not shown).

This is schematically illustrated in FIG. 4B, showing an enlarged view of the area marked by rectangle IVB in FIG. 4A. The base 60′ of the further package 100′ is elevated from the upper surface 18 of the lid 12 by the lower rim height hr and the circumferential ridge 20 is placed at an inside of the lower rim 62′ of the further package 100′. The base diameter dr' of the further package 100′ is arranged to agree with the outer ridge diameter do in order to form a stable stacking assembly upon vertically stacking the packages 100, 100′. In the illustrated embodiment, both diameters are equal to the base diameter dr.

FIG. 5A shows a two-dimensional (2D) pyramidal stack 110 of three identical packages 100, 100′, 100″ according to the present invention. Each package 100 is generally cylindrical but the sidewall 52 of the container 50 is contoured in shape and has a face 104 that is intended to be displayed. In the 2D pyramidal stack, the packages are assembled in vertically stacked rows of side-by-side aligned packages with all of the faces 104, 104′, 104″ oriented in the same direction. Each package 100″ in a row above is placed over two further packages 100, 100′ from a row below. The two further packages 100, 100′ are placed on a horizontal surface H such that a first package 100 is placed adjacent to and abutting a second package 100′. The lid structures 10, 10′ of the two further packages 100, 100′ are aligned and oriented parallelly, i.e. by parallelly aligning central lines C of the two further lid structures 10, 10′. A third package 100″ is then partially stacked over the two further packages 100, 100′.

The 2D pyramidal stack is further schematically shown in FIG. 5B. FIG. 5B shows in a top view, the two further lid structures 10, 10′ and a position of the lower rim 62″ of the third package 100″ upon stacking the three packages 100, 100′, 100″ together. The third package 100″ is positioned such that the lower rim 62″ is contemporaneously placed over the second ridge portion 20B of the first package 100 and the first ridge portion 20A′ of the second package 100″. When 2D pyramidally stacked, first ridge ends 74B, 74A′ and second ridge ends 76B, 76A′ of each of the two ridge portions 20A, 20B′ placed under the lower rim 62″ of the third package 100″ approach closely to the lower rim 62″ leaving of about 1 mm of a free-play space df between each ridge end 74B, 74A′, 76B, 76A′ and the lower rim 62″. The faces 104, 104′ must thus be oriented in the same direction towards a front side of the stack The 2D pyramidal stack formed in this manner is particularly stable, allowing tilting of the stack by an angle of around 45° with respect to the horizontal surface H before collapse of the stack. This is significantly more inclined than would be the case for a standard lid without the ridges 20, indicating a better stability to movement when stacked.

The present invention may be embodied in other specific forms without departing from its essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive to the inventive concept. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. It will be apparent to the person skilled in the art that alternative and equivalent embodiments of the invention can be conceived and reduced to practice. In addition, many modifications may be made to adapt a particular configuration or material to the teachings of the invention without departing from the essential scope thereof.

All modifications which come within the meaning and range of equivalency of the claims are to be embraced within their scope.