Patent Publication Number: US-2019177045-A1

Title: Packaging lid

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage of International Application No. PCT/NL2016/050847, filed Dec. 6, 2016, which claims the benefit of Netherlands Application No. NL 2015979, filed Dec. 17, 2015, the contents of which is incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a packaging lid for mounting over an (access) opening of a packaging container. The container is 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. The upper rim defines the opening of the container. 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. 
     BACKGROUND OF THE INVENTION 
     Containers combined with lids for packaging powdered or granular food products are well known in the art. Typical powdered food product for which these kind of packagings are used are infant formula or dietary supplements. Often these kinds of packagings are provided with a scoop by which a metered dose of powdered product can be taken from the container. The containers may have a cylindrical shape or may have a box-like shape with a substantially rectangular cross-section. 
     U.S. 2015/0129597 discloses an example of such a packaging. This known packaging includes a lid comprising an annular base which is attached to an upper end of the packaging container. A covering lid in hingedly attached to the base and is movable between a closed position in which the packaging is sealed and an open position in which the user has access to the content of the container. A latching assembly is present between the base and the covering lid to maintain the covering lid in a closed position when no powdered food product has to be taken from the container. The annular base has a series of flexible lips distributed over its inner circumference. The flexible lips each have a hook member at a lower end thereof to hook behind an edge of a series of indentations formed on circumference of the container. During mounting of the lid on the container, the hook members slide over the surface of the upper portion of the container. Thereby the flexible lips are flexed outwards. When the hook members reach the indentations, the hook members snap into the indentations due to the resilience of the lips. This known packaging requires an accurate match between the dimensions of the lid and of the container. In general, the lid can be mounted only on a container with accurately matching peripheral dimensions. In practise, different tolerances in manufacturing the lid and the container may lead to problems in the compatibility between the lid and the container. 
     The present invention has for an object to provide a lid in which the lid may be mounted on containers having different peripheral dimensions within a predefined range (thereby mitigating the problem induced by manufacturing tolerances). 
     SUMMARY OF THE INVENTION 
     This object is achieved by 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, 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. 
     The packaging lid according to the invention is mounted on the packaging container by placing the skirt with the lower end around the upper end of the container and then pushing it downwards. The arch formed strips are flattened when they contact the outwardly projecting ridge of the container and move beyond it. When the arch formed strips are beyond the outwardly projecting ridge they snap under said ridge so as to block removal of the lid from the container. The arch formed strips extend radially inward as far as the outer side of the circumferential wall of the container allows. Thus depending on the outer dimension of the container, the arch will return to its original shape or to a partially flattened shape. This provides a flexibility in the construction which allows compensation for dimensional variations in container and lid due to manufacturing tolerances. 
     The packaging lid according to the invention is preferably made of plastics material by injection molding. Suitable plastics material could be a PP or PE resin. It is also possible to make the lid of a combination of materials, like for example a combination of PP and TPE. 
     The arch formed strips are preferably arranged in a circumferentially distributed fashion over the inner surface of the skirt. 
     In a preferred embodiment of the packaging lid the strips extend in a substantial tangential direction of the inner wall of the skirt. 
     In a further embodiment 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. The lead-in edge guides the strip onto the projecting ridge and induces compression of the arch of the strip. Thereby the movement of the strip on and beyond the ridge is made easier. Thus the capping of the container is made easier. 
     In a possible embodiment said lead-in edge has a slanting surface. This facilitates the guiding effect of the edge onto the ridge. 
     In a further embodiment the lead-in edge may have 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 the centre of the strip. This shape has the effect that the strip is gradually compressed towards the centre of the strip by the outwardly projecting ridge of the container. This gradual compression reduces resistance caused by the strips during the mounting of the lid on the container. 
     In a further embodiment 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. When the lid is mounted on the container, the strips formed as arches are first compressed when they move along the projecting ridge of the container. When the strips have moved beyond said projecting ridge they expand again and the retaining edge of the strip hooks behind the projecting ridge. The retaining edge forms an abutment for said ridge which prevents that the lid can be withdrawn from the container. 
     Preferably the retaining edge is straight between the ends of the strip, which provides a tight fix of the lid on the container. 
     The retaining edge is preferably perpendicular to a front side of the strip. Also an acute angle between the retaining edge and a front side of the strip may be possible. In this way it is nearly impossible to remove the lid from the container without the use of undue force. 
     In a possible advantageous embodiment the strips are adapted to rupture if the lid is removed from the container. In this way the strips constitute a tamper-evident feature that indicates that the lid has been removed from the container. 
     In a preferred embodiment of the packaging lid according to the invention, 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. In one possible specific embodiment the segments are substantially linear. In another possible specific embodiment the segments are substantially curved. 
     In an alternative embodiment the arch has a continuous curve shape. 
     In another possible alternative embodiment the arch has substantially a “W” shape. 
     In a practical embodiment of the lid according to the invention the lid is of the type having a hingable cover. The lid comprises an annular base including said skirt attachable to the container and defining an access opening, and 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. This embodiment is in practise a convenient lid to use with containers containing infant formula or other powdered food product. The lid can be readily opened every time the product has to be taken from the container, for example with a scoop, and then be readily reclosed. The lid according to this practical embodiment can be formed in one piece, such that the annular base and the cover are formed with an integral living hinge which connects them. Another option is that the lid is an assembled piece in which the base and the cover are formed separately and are assembled and connected by a hinge structure. 
     In another conceivable embodiment of a lid according to the invention the skirt comprises a lower skirt portion and an upper skirt portion. The upper skirt portion is integrally connected to the top side of the lid. The lower skirt portion contains the arch formed strips. The lower skirt portion and upper skirt portion are connected by one or more frangible connections. The frangible connection may for example be constituted by frangible connection members or for example by a continuous weakening line (tearing line) provided in the skirt. The lid of this type can be mounted as is described in the above. To open the lid for the first time, the lower skirt portion and the upper skirt portion must be separated by rupturing the frangible connection. The lid with the upper skirt portion can be replaced after first time opening and will be retained by some snap or clamp connection between the upper skirt portion and the container or the lower skirt portion. 
     The invention also relates to a method to manufacture a lid as described in the above. 
     In particular the invention also relates to 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 the 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. A melt of plastic resin is injected in the mold cavity defined by the mold halves and the core parts. 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. 
     The invention will be elucidated in the following description with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a view in perspective of a packaging lid according to the invention; 
         FIG. 2  shows a detail of the lid of  FIG. 1  seen from below, with a resilient member in an expanded state; 
         FIG. 3  shows the same detail as  FIG. 2 , but with the resilient member in a compressed state; 
         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; 
         FIG. 5  shows the same detail as  FIG. 4 , but with the lid mounted on a container with a smaller diameter; 
         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; 
         FIG. 7  shows in perspective another embodiment of a packaging lid according to the invention; 
         FIG. 8  shows in a cross section a part of a mold in which the lid of  FIG. 1  is formed; 
         FIG. 9  shows in a cross section the opened mold of  FIG. 8  during a first ejection step; 
         FIG. 10  shows in a cross section the opened mold of  FIG. 8  during a second ejection step; 
         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 
         FIG. 12  shows a part of a lid from below with a resilient member having yet another shape. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     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. 
     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. 
     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). 
     A 2K injection molding process could also allow to make the strips from a different material as the skirt. 
     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 . 
     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. 
     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. 
     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 . 
     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 . 
     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 . 
     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. 
       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  35 A which is slanting. This is best seen in the cross sectional view of  FIG. 6 . The slanting edge  35 A 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 . 
     Opposite the lead-in edge each of the strips  35  has a straight upper edge  35 B. This straight upper edge  35 B 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 . 
     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. 
     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. 
     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. 
     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 . 
     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. 
     The mold half  52  defines the front side and the slanting edge  35 A 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  35 B of the strips  35  is defined by the movable core  54 . 
       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. 
       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 .