PACKAGING LID

Abstract

A packaging lid for mounting over an opening of a packaging container. The lid includes a top side that in a mounted state extends over an opening of the container and a skirt extending from the top side. The skirt has on an inner side thereof resilient members adapted to cooperate with an outwardly projecting ridge on an outer side of the circumferential wall of the container so as to secure the lid to the container. The resilient members are formed as resilient elongate strips having two ends attached to the inner side of the skirt and formed as an arch which, in an unloaded state, has a rise with respect to the inner side of the skirt.

Claims

1: A packaging lid for mounting over an (access) opening of a packaging container, said container being adapted in particular for packaging a powdered or granular food product and comprising a bottom and a circumferential wall which has an upper rim remote from the bottom, said upper rim defining the opening of the container, wherein the lid comprises a top side that in a mounted state extends over the opening of the container and a skirt extending from the top side towards a lower end, wherein the skirt has on an inner side thereof resilient members adapted to cooperate with an outwardly projecting ridge on an outer side of the circumferential wall of the container so as to secure the lid to the container, and wherein the resilient members are formed as resilient elongate strips having two ends attached to the inner side of the skirt and formed as an arch which, in an unloaded state, has a rise with respect to the inner side of the skirt.

2: The packaging lid according to claim 1, wherein the strips extend in a substantial tangential direction of the inner side of the skirt.

3: The packaging lid according to claim 1, wherein the strips have a lead-in edge to facilitate compression of the arch of the strip while moving the strip past said outwardly projecting ridge during mounting of the lid on the container.

4: The packaging lid according to claim 3, wherein the lead-in edge has a slanting surface.

5: The packaging lid according to claim 3, wherein the lead-in edge has a curved or pointed shape, wherein, seen in a radial direction of the lid, the lead-in edge at the ends of the strip is located closer to the lower end of the skirt than at a centre of the strip.

6: The packaging lid according to claim 1, wherein the strips have a retaining edge opposite the lead-in edge to engage an underside of said outwardly projecting ridge to retain the lid on the container.

7: The packaging lid according to claim 6, wherein the retaining edge is straight between the ends of the strip.

8: The packaging lid according to claim 1, wherein the arch is formed as a pointed segmental arch which comprises two segments which extend from the respective strip ends towards a join where the two segments join under an obtuse angle with respect to each other.

9: The packaging lid according to claim 8, wherein said segments are substantially linear.

10: The packaging lid according to claim 8, wherein said segments are substantially curved.

11: The packaging lid according to claim 1, wherein the arch has a continuous curve shape.

12: The packaging lid according to claim 1, wherein the lid comprises an annular base including said skirt attachable to the container and defining an access opening, and wherein the lid furthermore comprises a cover that is hingedly connected to the annular base and which is moveable between an open position in which the access opening is free and a closed position in which the access opening is covered.

13: The packaging lid according to claim 1, wherein the skirt comprises an upper skirt portion and a lower skirt portion, the upper skirt portion being integrally connected to the top side of the lid and the lower skirt portion containing the arch formed strips, wherein the lower skirt portion and upper skirt portion are connected by one or more frangible connections.

14: The packaging lid according to claim 1, wherein the lid is made of plastics material.

15: The packaging lid according to claim 1, wherein the lid is injection molded.

16: The packaging lid according to claim 15, wherein the lid is formed by 2K injection molding, wherein the strips are formed of a different material than the skirt.

17: A method for manufacturing a packaging lid, wherein the lid comprises a top side and a skirt extending from the top side, and wherein the skirt has on an inner side thereof resilient elongate strips having two ends attached to the inner side of the skirt and formed as an arch which, in an unloaded state, has a rise with respect to the inner side of the skirt, in which method an injection mold is provided defining a cavity to mold the packaging lid, said injection mold comprising two mold halves, movable core parts to define at least a part of the inner surface of the skirt and the upper edge of the strips, core parts to define the back side of the strips, and a movable ejector, in which a melt of plastic resin is injected in the mold cavity defined by the mold halves and the core parts, and wherein after the melt has been injected and sufficiently cured the movable core parts are moved inwards so as to release the strips, and the ejector pushes the formed lid away from the mold half and beyond the movable core parts so as to release the formed packaging lid from the mold.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a view in perspective of a packaging lid according to the invention;

[0027] FIG. 2 shows a detail of the lid of FIG. 1 seen from below, with a resilient member in an expanded state;

[0028] FIG. 3 shows the same detail as FIG. 2, but with the resilient member in a compressed state;

[0029] FIG. 4 shows a part of a cross section perpendicular to the central axis of the container of the lid of FIG. 1 mounted on a container with a certain diameter;

[0030] FIG. 5 shows the same detail as FIG. 4, but with the lid mounted on a container with a smaller diameter;

[0031] FIG. 6 shows a cross section according to the line II-II indicated in FIG. 5 of a detail of the lid of FIG. 1 mounted on a packaging container;

[0032] FIG. 7 shows in perspective another embodiment of a packaging lid according to the invention;

[0033] FIG. 8 shows in a cross section a part of a mold in which the lid of FIG. 1 is formed;

[0034] FIG. 9 shows in a cross section the opened mold of FIG. 8 during a first ejection step;

[0035] FIG. 10 shows in a cross section the opened mold of FIG. 8 during a second ejection step;

[0036] FIG. 11 shows a part of a lid from below with a resilient member having another shape as is shown in FIGS. 1-6; and

[0037] FIG. 12 shows a part of a lid from below with a resilient member having yet another shape.

DETAILED DESCRIPTION OF THE INVENTION

[0038] In FIG. 1 is shown a packaging lid 1 for mounting on a container for example baby formula, or another powdered or granular food product. The lid comprises a top side 2 and a skirt 3 that extends from the top side 2 toward a lower end 30 of the skirt. In the shown embodiment the top side is a closed plate.

[0039] In another embodiment of a lid according to the invention, which by way of example is shown in FIG. 7, the lid comprises an annular base 4 including a skirt 3 attachable to the container and defining an access opening. In this embodiment the lid furthermore comprises a cover 5 that is hingedly connected to the annular base 4 by a hinge 6 and which is moveable between an open position in which the access opening is free and a closed position (shown in FIG. 7) in which the access opening is covered.

[0040] Either of the lid types is an injection molded product made of a plastic resin, such as a PP or a PE resin. The entire lid, including the resilient strips, is then formed of the same material.

[0041] It is also possible that the lid is made by a 2K injection molding process. An example could be a lid formed of the components polypropylene (PP) and a thermoplastic elastomere (TPE).

[0042] A 2K injection molding process could also allow to make the strips from a different material as the skirt.

[0043] For a further explanation of the invention reference is made to FIG. 1, but it is to be understood that the features are also applied in a lid of the type as is shown in FIG. 7.

[0044] The skirt 3 has an inner side 31. Distributed over the circumference there are formed ribs 32 on the inner side 31 of the skirt 3. The ribs 32 extend in an axial direction. The ribs 32 have a lower end 33 that abuts an upper rim of the container when the lid 1 is mounted on the container. The ribs 32 have an upper end that may adjoin the top side 2 as is shown in FIG. 1, but in another embodiment the upper end of the rib 32 may also be spaced apart from the top side 2. The ribs 32 have a reinforcing effect, and make the lid 1 stiffer.

[0045] It is noted here that the ribs 32 are practical but not essential. Also a narrowing in the skirt or a circumferential rim on the inner side of the skirt can provide an abutment for the upper rim of the container and provide a reinforcing effect.

[0046] On the inner side 31 of the skirt 3, near a lower end thereof, are formed resilient strips 35 which are formed as an arch. The resilient strips 35 are distributed over the circumference of the skirt 3.

[0047] Each strip 35 has two ends 36 attached to the inner side 31 of the skirt 3. The strips 35 extend substantially in the tangential direction of the skirt 3 as can be seen in FIG. 1. In an unloaded state, which is shown in FIG. 1 and in more detail in FIG. 2, the arch has a rise h with respect to the inner side 31 of the skirt 3.

[0048] The arch is in the specific embodiment shown in the FIGS. 1-6 a pointed segmental arch which comprises two substantially linear segments 37 which extend from the respective strip ends 36 towards a join 38 in the centre, where the two segments 37 join under an obtuse angle with respect to each other as is best seen in FIG. 2.

[0049] It is noted that the arch shape can also be differently shaped as is shown in FIGS. 1-6. In FIG. 11 is shown an example wherein a resilient strip 35 is formed that has a continuously curved arch shape. In FIG. 12 is shown another example wherein a resilient strip 35 is formed that generally has a W shape. The given examples should not be interpreted as limiting for the invention; also other arch shapes are conceivable within the scope of the invention.

[0050] FIG. 6 shows a detail of the lid 1 mounted on a container 40. The container 40 has at its upper end an outwardly projecting ridge 42. Each of the strips 35 has a lower edge 35A which is slanting. This is best seen in the cross sectional view of FIG. 6. The slanting edge 35A works as lead in edge that facilitates compression of the arch of the strip 35 while moving the strip 35 past the outwardly projecting ridge 42 during mounting of the lid 1 on the container. A compressed strip 35 is shown from above in FIG. 3.

[0051] Opposite the lead-in edge each of the strips 35 has a straight upper edge 35B. This straight upper edge 35B functions as a retaining edge which engages an underside of said outwardly projecting ridge 42 to retain the lid 1 on the container 40. This is best seen in the cross sectional view of FIG. 6.

[0052] The arched strips 35 provide a flexibility in the construction which allows compensation for variations in the outer diameter of the container wall 41 and/or variations in the inner diameter of the lid due to manufacturing tolerances. The packaging lid 1 is mounted on the packaging container by placing the skirt 3 around the upper end of the container 40 and then pushing it downwards. The arch formed strips 35 are flattened when they contact the outwardly projecting ridge 42 of the container 40 and move beyond it. When the arch formed strips 35 are beyond the outwardly projecting ridge 42 they snap under said ridge 42 so as to block removal of the lid 1 from the container 40. The arch formed strips 35 extend radially inward as far as the outer side of the circumferential wall 41 of the container 40 allows. Depending on the outer dimension of the container 40, the arch will return to its original shape as is shown in FIG. 5 or to a partially flattened shape as is shown in FIG. 4. Hence, the problem of varying dimensions, for example due to manufacturing tolerances of the different parts, is resolved.

[0053] In the examples given in the figures the container and the lid have a circular cross section. It is noted however that also other cross sectional shapes of the container and the corresponding lid are conceivable. One can think of for example an essentially rectangular cross section with rounded corners, which is a quite common shape for packagings for infant formula.

[0054] In FIGS. 8-10 a possible working of a mold for the production of a lid of FIG. 1 is shown. Only a part of the cross section of the mold and the lid 1 is shown.

[0055] In FIG. 8 the mold 50 is shown in a closed state just after the lid 1 is formed out of a suitable plastic resin, such as a polypropylene (PP) resin. The mold 50 has mold halves 51 and 52. Furthermore the mold has core parts 53 and 56, movable core parts 54 each operable by a pin 55. The mold also includes an ejector comprising a movable ejector ring 58 operable by one or more pins 57.

[0056] In the embodiment shown the core 53 and the movable core 54 have a slanting interface 59. When the core 54 is moved it slides along the slanting interface 59. When the movable core 54 is moved away from the mold half 52, it simultaneously moves radially inwards and vice versa.

[0057] The mold half 52 defines the front side and the slanting edge 35A of the strips 35. The core part 56 forms the back side of the strips 35 as can be clearly seen in FIG. 8. Furthermore the straight retaining edge 35B of the strips 35 is defined by the movable core 54.

[0058] FIG. 9 shows a first ejection step in which the mold half 51 is moved apart from the mold half 52. The movable core part 54 and the ejector ring 58 are moved away from the mold half 52 whereby the lid 1 is ejected from the mold half 52. The movable core part 54 also moves radially inward whereby the strips 35 formed on the inner side of the skirt 3 can pass beyond the core part.

[0059] FIG. 10 shows that the movable core part 54 has stopped and that the ejector ring 58 is moved on in a second ejection step so as to raise the upper side 2 of the lid 1 of the movable core part 54 and to move the resilient strips 35 beyond the movable core 54. In this way the skirt 3 of the lid 1 is ejected entirely from the mold half 52 and the core parts 56.