HK1114592A1 - Container, cover thereof and container cover systems - Google Patents

Abstract

The container covers (102, 1102) stack together in two different ways. First, the covers can be stacked into an "aligned" stack. The aligned stack provides structural rigidity for bulk handling during manufacturing. Second, the covers can be stacked into a "locked" stack. The locked stack provides even more structural rigidity than does the aligned stack and is useful when storing unused covers. The container cover includes a first closure portion (700), an engagement portion (200), and alignment portion (900). The base (104,1100) includes a second closure portion (702). The first closure portion of the cover is sealingly engageable with the second closure portion of the base to define a sealed storage area. The alignment portion of the cover is engageable with the alignment portion of a second cover (1102) to form an aligned cover stack. The engagement portion of the cover is engageable with the engagement portion (200) of a second cover to form a locked cover stack.

Description

Container, lid for a container and container lid system

Technical Field

The present invention relates generally to containers and, more particularly, to a container having lids that align together when stacked in a first position and are lockable together in a second position.

Background

Rigid, thermoplastic food containers are generally known. Users often accumulate a large number of such containers of different sizes and shapes. When not in use, the containers are typically stored in drawers ad libitum. In this case, unused containers take up a lot of space and finding a matching base and lid in a cluttered drawer is difficult. To avoid this, some users stack the containers in cabinets. While the bases of the containers typically nest within each other and therefore occupy less space than in a garbled drawer, it is still difficult to mate the bases with the lids. In addition, the lids may not be stacked and tend to be upside down. When the containers are used to store food items, the containers are typically stacked one on top of the other in a cabinet or refrigerator. These stacks can be unstable and their dropping can cause the food to spill out of the container. Many users will find it desirable if containers (whether empty or in use) can be stored in a space-saving, less unstable and more structurally rigid manner.

In mass production, the lids may be transported in batches before being separated into individual packages. In batch handling, manufacturers may find it desirable if the lids form a sufficiently secure stack to prevent longitudinal and lateral movement due to forces typically encountered in production operations.

It is a general object of the present invention to provide a container that meets the needs of both the user and the manufacturer.

Disclosure of Invention

In view of the above, the present invention provides a container whose lids can be stacked together in two different ways. First, the covers can be stacked into an "aligned" stacked stack. The aligned stacked stack provides sufficient structural rigidity for bulk transport during the manufacturing process. Second, the covers can be stacked into a "locked" stacked stack. The locked stack provides even greater structural rigidity than an aligned stack and is more useful in storing unused lids.

In some embodiments, the container lid includes a first closure portion, an engagement portion, and an alignment portion. The base includes a second closure portion. The first closure portion of the lid is sealingly engaged with the second closure portion of the base to define a substantially sealed, leak-proof and resealable storage area for objects such as food items. The alignment portion of the lid is engageable with an alignment portion of a second lid to form an aligned lid stack. The engaging portion of the lid is engageable with an engaging portion of a second lid to form a locked lid stack.

More specifically, according to one aspect of the present invention, there is provided a container comprising: a first cover comprising a first closure portion, an engagement portion and an alignment portion, the first closure portion being sealingly engageable with a second closure portion of a base such that when the first and second closure portions are engaged with one another, the first cover and the base define a substantially sealed storage area, wherein a plurality of adjacent, stacked covers forming a vertically aligned cover stack are configurable into a first, locked configuration and a second, unlocked configuration, wherein: said engagement portion of said first cover comprising an upper projection and being engageable with an engagement portion of a second cover, wherein said second cover comprises a lower projection; and, in the first locking configuration, the lower projection fits over and receives the upper projection to lock the two covers together; and in a second, non-locking configuration, the alignment portion of the first lid is engageable with the alignment portion of the second lid to form an aligned nested lid stack that is sufficiently robust to prevent longitudinal, lateral or rotational movement caused by forces typically generated during a manufacturing operation, while allowing nesting of one or more lids in the lid stack to be undone after a given force is applied; the alignment portion of the first cover is located on the first closure portion and on the engagement portion; and the base includes a bottom, a peripheral sidewall extending from the bottom, an open top, and the second closure portion.

According to another aspect of the present invention, there is provided a first cap for a container, the first cap comprising: a first enclosing section; an engaging portion; an alignment portion, wherein the first closure portion is sealingly engageable with a second closure portion of a base such that when the first and second closure portions are engaged with one another, the first cover and the base define a substantially sealed storage area; wherein a plurality of adjacent and stacked lids forming a vertically aligned lid stack are configurable into a first locked configuration and a second unlocked configuration, wherein: the engaging portion of the first cover includes an upper projection and is engageable with an engaging portion of a second cover; wherein the second cover includes a lower protrusion; and, in the first locking configuration, the lower projection fits over and receives the upper projection to lock the two covers together; in a second, non-locking configuration, the alignment portion is engageable with the alignment portion of the second lid to form an aligned nested lid stack that is sufficiently robust to prevent longitudinal, lateral, or rotational movement caused by forces typically generated during a manufacturing operation, while allowing nesting of one or more lids in the lid stack to be undone after a given force is applied; the alignment portion of the first cover is located on the first closure portion and on the engagement portion.

According to a third aspect of the present invention there is provided a container lid system, the system comprising: a first cover comprising a first closure portion, an engagement portion and an alignment portion, wherein the first closure portion is sealingly engageable with a second closure portion of a base such that when the first and second closure portions are engaged with one another, the first cover and the base define a substantially sealed storage area; and a second cover comprising a first closure portion, an engagement portion and an alignment portion, wherein a plurality of adjacent and stacked covers forming a vertically aligned cover stack are configurable in a first locked configuration and a second unlocked configuration, wherein: the engaging portion of the first cover includes an upper projection and is engageable with an engaging portion of the second cover; wherein the second cover includes a lower protrusion; and, in the first locking configuration, the lower projection fits over and receives the upper projection to lock the two covers together; in a second, non-locking configuration, the alignment portion of the first lid is engageable with the alignment portion of the second lid to form an aligned nested lid stack that is sufficiently robust to prevent longitudinal, lateral, or rotational movement caused by forces typically generated during a manufacturing operation, while allowing nesting of one or more lids in a lid stack to be undone after a given force is applied; the alignment portion of the first cover is located on the first closure portion and on the engagement portion.

The cover and base can be economically constructed from relatively thin gauge plastic so that the user can clean them after use or discard them because their purchase price allows them to be used as consumable goods. The container can be easily manufactured, for example, using conventional thermoforming equipment. The cover may be made of a translucent material to ensure adequate visibility of the contents of the container. The container may be suitable for refrigerator, freezer, microwave, and mechanical dishwasher applications.

The features of the present invention will be apparent to those of ordinary skill in the art upon reading the detailed description in conjunction with the drawings provided herein.

Drawings

FIG. 1 is an isometric view of a container having a lid and a base according to an embodiment of the present invention;

FIG. 2 is an isometric view of the container lid shown in FIG. 1;

FIG. 3 is a top plan view of the container lid shown in FIG. 1;

FIG. 4 is an isometric view of the container lid shown in FIG. 1;

FIG. 5 is a top plan view of the container base shown in FIG. 1;

FIG. 6 is a side cross-sectional view of the container shown in FIG. 1;

FIG. 7 is an enlarged detail view of a portion of FIG. 6;

FIG. 8 is a side cross-sectional view of another embodiment of the container shown in FIG. 7;

FIG. 9 is a side cross-sectional view of another embodiment of the container shown in FIG. 7;

FIG. 10 is a side cross-sectional view of a stack of two sealed containers;

FIG. 11 is a side cross-sectional view of a stack of two nested container bases with two locked container lids;

FIG. 12 is a side cross-sectional view of another embodiment of the stacked stack of FIG. 11;

FIG. 13 is a side cross-sectional view of two nested container bases with a locked container lid and an alignment lid;

FIG. 14 is a side cross-sectional view of another embodiment of the stacked stack of FIG. 13;

FIG. 15 is a side cross-sectional view of the aligned stacked stack of the container lid and base;

FIG. 16 is a side cross-sectional view of a stack of two nested container bases with two aligned container lids;

FIG. 17 is a side cross-sectional view of a stack of two nested container bases with an alignment container lid and a locking container lid;

FIG. 18 is a side sectional view of a two container lid locked stacked stack;

FIG. 19 is an enlarged detail view of a portion of FIG. 18;

FIG. 20 is a side sectional view of a two container lid stack in alignment;

FIG. 21 is an enlarged detail view of a portion of FIG. 20;

FIG. 22 is a flow chart of steps in an exemplary manufacturing process for manufacturing containers according to the present invention; and

FIG. 23 is a flow chart of steps in another exemplary manufacturing process for manufacturing containers according to the present invention.

Detailed Description

Turning to the drawings, wherein like reference numerals refer to like parts, fig. 1 to 5 show a first embodiment of the present invention. The container 100 includes a flexible cover 102 sealingly joined to a base 104. In the embodiment of fig. 1-5, the container 100 is illustrated as being generally square with rounded corners. In another embodiment of the present invention, the container 100 has other shapes, such as rectangular, circular, or oval.

The container lid 102 can include at least one gripping tab 106 to facilitate removal of the lid 102 from the container base 104. In some embodiments, the grip tab 106 includes one or more cross ribs or textured surfaces to improve the grip of the user on the tab 106.

The container lid 102 shown in fig. 2 and 3 includes an engagement portion 200 that allows the lid 102 to engage with the engagement portion 200 of a second lid 102 to form a locked stack of lids 102. This locking feature makes the resulting lid stack more structurally robust and therefore less unstable than conventional, non-interlocking lid stacks.

The engaging portion 200 in fig. 2 and 3 is illustrated as circular, however, other shapes are possible as well as the shape of the container 100 itself. In some embodiments, the standard shape and configuration of the engagement portion 200 is used for covers 102 of various shapes and sizes. This enhances flexibility of storage by allowing different types of covers 102 to be stored together to form a locked stacked stack. The engagement portion 200 may also be selected to have a shape or otherwise include features that provide an aligned or locked stack of covers 102 by rotational alignment, wherein rotation is defined about an axis perpendicular to the orientation 302 at which the centerlines 304 and 306 of the covers 102 intersect, as shown in FIG. 3. For example, the shape that inherently requires alignment before joining or that can be self-aligned in the step of connecting the joined components is a shape having linear or curvilinear sides, vertices or lobes, such as triangular, square, rectangular or multi-lobed shapes. In addition, the cover may have one or more features on or around the engagement portion that need to be aligned prior to connection of the engagement portion or that may be self-aligning during the step of connecting the engagement portion.

The container cover 102 has a central region 300 that is located at the top of the engaging portion 200 as shown in fig. 3. The central region 300 includes raised symbols, such as a manufacturer's logo or allows a user to attach a label or write information, such as a date or user name. When the central region 300 includes a writable region, the region may be an opaque color that receives a contrasting color from the writing instrument. The writable region may be integrated with the material of the container cover 102 or may be applied to the material by printing.

The container lid 102 of fig. 1-3 may be constructed with a wall that is thinner than the wall of the container base 104. The cover 102 may be made of any suitable plastic and by any suitable technique, such as thermoforming. In one embodiment, the cover 102 may be made of polypropylene. The wall thickness of the cover 102 may vary due to the thermoforming process. A thinner container lid 102 reduces material costs and increases flexibility to more easily accommodate its removal from the container base 104 and engagement with the container base 104. The cover 102 may remain suitably flexible to seal properly even at typical freezer temperatures.

The container base 104 in figures 4 and 5 includes a base 400 and a sidewall 402 extending from the periphery of the base 400. The bottom 400 includes a raised lower portion 404 to accommodate the engagement portion 200 of the container cover 102 when the containers 100 are stacked together. This feature is further illustrated and described below. Just as the engaging portion 200 in fig. 3 may include a central region 300, the same area for manufacturer's markings or user information may be included in the raised portion 404 of the base 104.

The container base 104 of fig. 1, 4 and 5 may be made of any suitable plastic of sufficient thickness to withstand without deformation the heat of microwave cooking and the top rack of a dishwasher. It also remains firm during lifting when filled with hot food. The base 104 may be made of any suitable plastic and by any suitable technique, such as co-extrusion, lamination, injection molding, thermoforming, or overmolding. In one embodiment, the container base 104 is made of polypropylene. The wall thickness of the container base 104 may vary depending on the manufacturing process.

Fig. 6-9 present an embodiment of the container 100 of the present invention with its lid 102 sealingly engaged with its base 104. Figure 6 illustrates the cover 102 cooperating with the base 104 to define a sealed storage compartment 600. The lid 102 is sufficiently flexible to allow a user to create a vacuum within the container 100 while sealed. To create the vacuum, the user may, for example, depress the lid 102 during closure of the container 100. The restoring force imparted on the cover 102 by the resiliency of the material of the cover 102 will urge the cover 102 to return to its normal position, thereby creating a vacuum. To facilitate easy sealing engagement of the cover 102 with its base 104, the user may, at his discretion, simply apply a force downwardly to the engagement portion 200 of the container cover 102. The engagement portion 200 is positioned to receive and transmit this force to the first closure portion 700 of the cover 102 during sealing to the base 104. The engagement portion 200 may also serve as a convenient handle for grasping the cover 102.

In the embodiment of fig. 6-9, the container 100 utilizes a locking rim design that includes both internal and external seals, as will be explained. The present invention may be implemented with various closure designs, including external closures and/or internal closures.

Fig. 7 illustrates an embodiment of a closure portion for engaging the lid 102 with the base 104 of the container 100. The cover 102 includes a first closure portion 700 in the form of a raised locking ring. The first closure portion 700 of the cover 102 is engageable with the second closure portion 702 of the base 104 to provide a leak-proof, resealable closure.

The first closure portion 700 includes an inner wall 704, a retention bead 706, and an outer wall 708. The inner wall 704, the retention bead 706, and the outer wall 708 define a first sealing surface that is part of the lower surface of the cover 102. The first closure portion 700 may include one or more locking ridges 710. The outer wall 708 extends between the retention bead 706 and a flange 712. The flange 712 may provide a convenient gripping surface to facilitate removal of the cover 102 from the base 104.

As shown in fig. 7, the second closure portion 702 of the base 104 is a raised locking ring that extends from the upper edge of the side wall of the base 104. The second closure portion 702 includes an inner wall 714, a retention bead 716, and an outer wall 718. The inner wall 714, the retention bead 716, and the outer wall 718 define a second sealing surface that is part of the upper surface of the base 104. The second closure portion 702 may include one or more locking ridges 720. The outer wall 718 extends between the retention rim 716 and the flange 722. The flange 722 may provide a convenient gripping surface to facilitate removal of the cover 102 from the base 104.

The first and second closure portions 700 and 702 may be configured to be slightly different in size so as to form an interference fit therebetween. An interference fit between the first and second closure portions 700 and 702 can provide a sealing engagement therebetween. As a result, when the two components are engaged, a positive seal may be formed between the first and second sealing surfaces around the periphery of the base 104 and the cover 102.

The engagement of the first and second closure portions 700 and 702 is accompanied by an audible "snap" indicating that the container is securely closed.

In the embodiment of fig. 7, the inner wall 704 of the first closure portion 700 of the cover 102 extends to the engagement portion 200. This engagement portion 200 includes an upper protrusion 724 and a lower protrusion 726.

In the embodiment of fig. 7, the cover 102 includes a ridge 728 on the outer wall 708 of the first closure portion 700. Figure 8 shows another embodiment without this ridge. In general, the first and second closure portions 700 and 702 and the engagement portion 200 illustrated in fig. 6-9 are merely examples, and many other types of closure and engagement portions may be used with the present invention. For example, the engagement portion 200 includes a complementary locking ring. Since these and many other types of closure and engagement portions are well known in the art, they need not be set forth herein in detail.

Fig. 9 illustrates another embodiment of the cover. The cover 102 in fig. 9 includes an alignment ridge 900 on the outer wall 708 of the first closure portion 700. This alignment ridge 900 will be described in detail below.

In fig. 10, the sealed container 100 is placed on top of a second sealed container 1000. The raised lower portion 404 of the base 104 of the upper container 100 accommodates the engagement portion 200 of the cover 1002 of the lower container 1000.

Fig. 11 and 12 show the application of the embodiment of the invention when the container is in the storage state. In the figure, a stack of two nested container bases 104 and 1100 are connected into a locked stack of covers 102 and 1102. The lower cover 102 sealingly engages the upper base 104 to form a structurally rigid stacked stack.

In the embodiment of fig. 11 and 12, the two covers 102 and 1102 are locked together by their engaging portions 200. As described in relation to fig. 7, each engagement portion 200 includes an upper protrusion 724 and a lower protrusion 726. Each protrusion 724, 726 is convex on one side and concave on the other. The lower protrusion 726 of the upper cover 1102 fits over and receives the upper protrusion 724 of the lower cover 102, thus locking the covers 102 and 1102 together. In this manner, the covers 102 and 1102 are held together and form a structurally rigid cover stack. Other embodiments of the engagement portion include one or more of the following to enable engagement: raised portions or ribs, recessed portions or ribs, linear or curvilinear undercuts, discontinuous snap members or buttons, interference fits, textured surfaces, members that change the friction or tackiness of the surfaces at or around the joint. The engagement region that creates the locked condition may be continuous around the engagement portion or discretely segmented around the engagement portion. In some embodiments, the force required to attach the cover is substantially different from the force required to detach the cover. For example, it is beneficial in the manufacturing process that the force required to attach the cover is less than the force required to detach the cover. Thus, the covers are relatively easy to attach during manufacture, but they will be securely locked and will not undesirably separate during manufacture. To achieve this, it is possible to design the projections on the engagement portion, wherein for a given projection the upper projection edge comprises a tapering taper, whereas the lower projection edge comprises a steeper shape. For example, in one embodiment, the shape of the protrusion may be the same as a barb having a tapered taper on the upper edge that may impart little resistance in engagement, and a steep shape on the lower edge that may impart relatively high resistance in disengagement. Conversely, it is beneficial to design the engagement portion so that the force required to attach the lid is greater than the force required to detach the lid, since the user may feel that a high attachment force equates to sufficient locking integrity, whereas a weak attachment force causes the user to feel that the lid stack lacks the integrity required to ensure the desired construction advantage. Thus a high connection force provides a perceived benefit, while a lower separation force does not require the user to bothersome effort in separating the lid. To achieve this, it is possible to design the projections on the engagement portion, wherein for a given projection the upper projection edge comprises a steep shape and the lower projection edge comprises a more tapered cone shape. For example, in one embodiment, the shape of the protrusion may be an inverted barb having a steep shape on the upper edge that may impart relatively high resistance during engagement, and a tapered shape on the lower edge that may impart little resistance during disengagement. Also, the engagement portions may provide tactile or audible feedback upon locking during application of force by a user to align the covers in a direction perpendicular to the general plane of the covers to lock the covers together. In this way the user can feel that the lid is attached and does not need to exert force.

The container bases 104 and 1100 illustrated in figures 11 and 12 are nested with one another rather than locked together. In many applications, nesting the container bases without locking them together provides sufficient structural stability to the stacked base stacks. However, it is possible to employ the techniques of the present invention on the bases themselves and thus provide a mechanism to lock the bases together. The same types of closure and engagement portions that can be used to lock the covers together or to lock the covers to the bases can be used to lock the bases together.

The container covers 102 and 1102 in fig. 11 include the ridge 728 described with respect to fig. 7, while the cover in fig. 12 does not include this feature. The ridges 728 provide a stabilizing function to the outer wall 708 and also provide a retention ledge to help eliminate nesting of the covers during manufacturing.

Figures 13 and 14 show another condition of the lid stack of figures 11 and 12. The container bases 104 and 1100 nest with one another and the lower cover 102 is locked onto the upper base 104. However, the upper cover 1102 is not locked to the lower cover 102. Instead, the upper cover 1102 is positioned over and aligned with the lower cover 102. In this configuration, the two covers 102 and 1102 are said to form an "aligned" stack to distinguish it from the locked stack of fig. 11 and 12. The ability to form an aligned, rather than locked, stack is important in manufacturing because it allows the lids to be transported in batches before being separated into individual packages. The aligned stacked stacks are sufficiently robust to prevent longitudinal, lateral or rotational movement caused by forces typically generated during manufacturing operations, but the covers are not so securely attached that they interfere with denesting, if necessary.

The tabs 106 (see fig. 1) can be designed to enable the tabs to nest within one another in an interdigitating fashion when in the lid stacking condition to maintain the lids in an aligned configuration. In one embodiment, the design of tab 106 allows for a secure lid-to-lid stack immediately adjacent to tab 106 in the locked state, such that a portion of tab 106 rests on a portion of the lid below it in the stack to provide resistance to further stack compression.

In the embodiment of fig. 13, the covers 102 and 1102 are aligned by tapping on both regions. First, each engagement portion 200 in the covers 102 and 1102 includes a lower shoulder 1300 and an upper shoulder 1302. The lower shoulder 1300 of the upper cover 1102 rests on the upper shoulder 1302 of the lower cover 102. Second, the flange 712 of the upper cover 1102 rests on the outer wall 708 of the lower cover 102. These two contact areas are used to align the covers 102 and 1102 into a stack that is less structurally rigid than the locking stack, but is already sufficiently rigid for many purposes. A comparison of figures 11 and 13 illustrates how the aligned stack is converted into a locked and rotatably aligned stack by applying pressure on the stacked objects. FIG. 11 illustrates the flange 712 of the upper cover 1102 being pushed further below the outer wall 708 of the lower cover 102 when a force is applied to the aligned stack of FIG. 13 to create a locked stack. The alignment cover is further strengthened by tapping the covers 102 and 1102 at the inner wall of the closure portion. In the embodiment of fig. 11, the lid inner wall 704 includes an upper shoulder 1104 located just above the uppermost locking ridge 710 and a lower shoulder 1106 located just below the lowermost locking ridge 710. Thus, in the pair of locked covers, the lower shoulder 1106 of the cover 1102 rests on the upper shoulder 1104 of the cover 102. According to fig. 11 and 13, the flange 712 creating the aligned condition may be continuous along the peripheral path of the first closure portion 700 or discontinuously segmented along the peripheral path of the first closure portion 700. According to fig. 12, the contact shoulders 1104 and 1106 of the inner wall 704 that create the alignment between the locking caps may be continuous along the peripheral path of the first closure portion 700 or discontinuous segments along the peripheral path of the first closure portion 700. In some embodiments, such alignment features are required to ensure that the attached covers are rotationally aligned about an axis perpendicular to the center of the covers, particularly when the covers include engagement portions that allow rotation between the covers. In some embodiments, if the alignment feature is absent, the cover will be free to rotate. Free rotation can have undesirable consequences because the stack of lids may not be properly organized for ease of manufacture or may not provide a configuration advantage to the user properly.

The embodiment of fig. 14 differs from that of fig. 13 in that the flange 712 of the upper cover 1102 does not descend far enough to contact the lower cover 102 when the covers 102 and 1102 are in an aligned stacked stack. Variations such as those between the embodiments of fig. 13 and 14 may be selected to vary the amount of rigidity exhibited by the aligned stacked stack. Even if the flange 712 of the upper cover 1102 does not descend far enough to contact the lower cover in such a less rigid aligned stacked stack, the contact between the lower shoulder 1300 of the engagement portion 200 of the upper cover 1102 and the upper shoulder 1302 of the lower cover 102 may provide a concentric or rotational alignment to help the user align the engagement portion 200 during attachment of the covers. Comparing figures 12 and 14 illustrates how an aligned stacked stack can be converted to a locked or rotationally aligned stacked stack by applying pressure on the stacked objects. FIG. 12 illustrates that when force is applied to the aligned stack of FIG. 14 to create a locked stack, the aligned covers are further strengthened by lightly pressing the covers 102 and 1102 in two areas. First, the flange 712 of the upper cover 1102 rests on the outer wall 708 of the lower cover 102. Second, the lower shoulder 1106 of the upper cover 1102 rests on the upper shoulder 1104 of the lower cover 102. In some embodiments, such alignment features are desirable to ensure rotational alignment of attached covers about an axis perpendicular to the center of the covers, particularly when the covers include engagement portions that allow rotation between the covers.

Figure 15 illustrates that the container cover 102 can be aligned on top of the container base 104 without locking. Figure 16 illustrates two covers 102 and 1102 in alignment stacked on top of a nested stack of bases 104 and 1100. Fig. 17 differs from fig. 16 in that the upper cover 1102 is locked over the lower cover 102. A comparison of figures 16 and 17 illustrates how an aligned stacked stack can be converted into a locked stacked stack by applying pressure on the stacked objects.

Figure 16 also illustrates another embodiment of the alignment portions of the container covers 102 and 1102. The alignment ridge 900 is located on the outer wall 708 of the covers 102 and 1102. When in the aligned stacked stack, the flange 712 of the upper cover 1102 rests on the alignment ridge 900 of the lower cover 102 to increase the rigidity of the stacked stack. FIG. 17 illustrates the flange 712 of the upper cover 1102 being pushed past the alignment ridge 900 of the lower cover 102 when pressure is applied to the aligned stacked stack to create a locked stacked stack.

Figures 18 and 19 emphasize the tightness of the locked stacked stack of container covers 102 and 1102, while figures 20 and 21 emphasize the tightness of the aligned stacked stack of container covers. Although the aligned stacked stacks are not as tight as the locked stacked stacks, the tightness of either stacked stack is a significant benefit of the present invention when storing lids for future use.

Fig. 22 shows a high level overview of a typical manufacturing process for making a container according to the present invention. The extruded plastic sheet (step 2200) is thermoformed into blank bases (step 2202). Excess plastic is trimmed from the blank bases (step 2204) and the finished bases are then nested with one another in a stack (step 2206) for further processing.

In a step parallel to the above steps, the cover is manufactured by the same process (steps 2212 to 2218). In steps 2216 and 2218, the finished covers need not be locked together because the aligned cover stack is sufficiently rigid for batch processing.

To package the completed bases and lids, the appropriate number of bases (steps 2208 and 2210) and lids (steps 2220 and 2222) are removed from their respective stacks. The bases and covers are stacked and combined with packaging material (steps 2224 through 2228) to create a single retail unit 2230 (which may include multiple bases and covers). The individual retail units are then packaged together in bulk for transport to retail outlets.

Fig. 23 shows a variation of the manufacturing process based on fig. 22. In the embodiment of fig. 23, the home is processed by the same steps 2200 through 2210. However, at step 2316 in fig. 23, the covers are locked together in a stacked manner rather than forming an aligned stacked stack as in step 2216 of fig. 22. In some manufacturing environments, the increased structural rigidity makes a locked lid stack more suitable than an aligned lid stack. The locked stack of lids is processed through steps 2318, 2220 and 2322. In step 2224 of fig. 23, an appropriate number of locking covers are combined with the base and packaging material to form a single retail unit 2330.

The container may be reusable, but it may also be constructed inexpensively enough for the user to view it as a disposable item, with a replaceable lid and base for retail sale, respectively. The base and lid may be made by thermoforming a clarified polypropylene homopolymer material. In another embodiment, the container may be made by thermoforming a clear random copolymer polypropylene material. Other plastic materials suitable for making containers by thermoforming include PS (polystyrene), CPET (crystalline polyethylene terephthalate), APET (amorphous polyethylene terephthalate), HDPE (high density polyethylene), PVC (polyvinyl chloride), PC (polycarbonate) and foamed polypropylene. The material used may be substantially transparent to allow the user to view the contents of the container.

The container may include a visual indication of the closure between the container lid and the container base. The visual indication may be a change in colour in the region where the cover engages the base. In one embodiment, the closure portion on the lid may be a first color and the closure portion on the base may be a second color. When the closure portions are engaged, the first and second colors produce a third color that is visible to a user to indicate that the container is sealed.

The container may include a roughened outer surface to reduce slippage and improve user grip, especially if the user's hands are wet or greasy.

The container may include a self-venting feature. The pressure within the sealed container may increase as the sealed container and contents are heated by the microwave oven. Thus, the container lid may include a self-venting mechanism that opens when the pressure within the container exceeds a predetermined value.

The container may be divided to separate the food items within the container. The divider may be integral with the container or a separate component. Either the base includes only the spacer or the base and the cover each include the spacer. The divider located within the lid may only partially engage the divider within the base to provide splash protection, or may fully engage the divider within the base to provide varying degrees of inter-compartment leakage resistance.

The container may include a strip indicating the temperature of the container and its contents.

The grip tab may include a protruding portion that provides less interference contact with the base during removal or engagement of the cap, while still providing sufficient closure to maintain a proper container seal. The projecting portion of the gripping tab allows venting by unsealing a portion of the lid from the base while still maintaining a seal around the remaining periphery of the container. This feature is useful in microwave cooking where the lid prevents food from splashing onto the inside surface of the microwave oven while still allowing the container to vent. By using a gripping tab, less force is required to remove the cover from the base. This lower opening force also reduces the likelihood of the container being damaged by pressure and fatigue. A lower opening force may improve the ability of the user to maintain control over the container components when removing the lid from the base, thereby reducing the likelihood of spilling the contents stored in the container.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed.

While the invention is described herein in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, it is to be understood that various changes and modifications to the described embodiments will be apparent to those skilled in the art based on a reading of the foregoing description, and that such changes and modifications may be made without departing from the spirit and scope of the invention. The skilled artisan can implement such variations as appropriate, and the invention can be practiced otherwise than as specifically described herein. Accordingly, the invention is intended to cover all alternatives, modifications, and equivalents that may be included within the spirit and scope of the invention. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims (23)

1. A container, comprising:

a first cover including a first closure portion, an engagement portion and an alignment portion, the first closure portion being sealingly engageable with a second closure portion of a base such that when the first and second closure portions are engaged with one another, the first cover and the base define a substantially sealed storage area,

wherein a plurality of adjacent and stacked lids forming a vertically aligned lid stack are configurable into a first locked configuration and a second unlocked configuration, wherein:

said engagement portion of said first cover comprising an upper projection and being engageable with an engagement portion of a second cover, wherein said second cover comprises a lower projection; and, in the first locking configuration, the lower projection fits over and receives the upper projection to lock the two covers together, wherein the second cover rests on an outer wall (708) of the first cover, the second cover includes a lower shoulder (1300), the first cover includes an upper shoulder (1302), and the lower shoulder of the second cover rests on the upper shoulder of the first cover; and is

In a second, non-locking configuration, the alignment portion of the first lid is engageable with the alignment portion of the second lid to form an aligned nested lid stack that is sufficiently robust to prevent longitudinal, lateral, or rotational movement caused by forces typically generated during a manufacturing operation, while allowing nesting of one or more lids in the lid stack to be undone after a given force is applied; and

the base includes a bottom, a peripheral sidewall extending from the bottom, an open top, and the second closure portion.

2. The container of claim 1, wherein the first lid and the base comprise thermoformed plastic.

3. The container of claim 1, wherein the first and second closure portions include locking rings, the locking rings of the first and second closure portions each including an inner wall, a retaining rim, and an outer wall.

4. The container of claim 1, wherein the first closure portion of the first cap is engaged with a first closure portion of the second cap.

5. The container of claim 1, wherein the engagement portion includes a rib and a detent, wherein the rib of the engagement portion of the first lid is engageable with the detent of the engagement portion of the second lid.

6. The container of claim 1, wherein the first cover includes a grip tab.

7. The container of claim 1 wherein the bottom, the peripheral side wall and the open top of the base define a cavity and the base is partially insertable into the cavity of a second base.

8. The container of claim 1, wherein the alignment portion of the first cap comprises a member selected from the group consisting of a flange, a protrusion, and a locking ring.

9. A first cap for a container, the first cap comprising:

a first enclosing section;

an engaging portion;

an alignment portion is provided on the outer surface of the housing,

wherein the first closure portion is sealingly engageable with a second closure portion of a base such that when the first and second closure portions are engaged with one another, the first cover and the base define a substantially sealed storage area;

wherein a plurality of adjacent and stacked lids forming a vertically aligned lid stack are configurable into a first locked configuration and a second unlocked configuration, wherein:

the engaging portion of the first cover includes an upper projection and is engageable with an engaging portion of a second cover; wherein the second cover includes a lower protrusion; and, in the first locking configuration, the lower projection fits over and receives the upper projection to lock the two covers together;

in a second, non-locking configuration, the alignment portion is engageable with the alignment portion of the second lid to form an aligned nested lid stack that is sufficiently robust to prevent longitudinal, lateral, or rotational movement caused by forces typically generated during a manufacturing operation, while allowing nesting of one or more lids in the lid stack to be undone after a given force is applied.

10. The first cover of claim 9, wherein the first cover comprises a thermoformed plastic.

11. The first cap of claim 9, wherein said first closure portion includes a locking ring, said locking ring of said first closure portion including an inner wall, a retaining rim and an outer wall.

12. The first cover of claim 9, wherein the first closure portion of the first cover is engageable with a first closure portion of the second cover.

13. The first cover of claim 9, wherein said engagement portion includes a rib and a detent, wherein said rib of said engagement portion of said first cover is engageable with said detent of said engagement portion of said second cover.

14. The first cover of claim 9, wherein the first cover includes a grip tab.

15. The first cap of claim 9, wherein the alignment portion of the first cap comprises a member selected from the group consisting of a flange, a protrusion, and a locking ring.

16. A container lid system, the system comprising:

a first cover comprising a first closure portion, an engagement portion and an alignment portion, wherein the first closure portion is sealingly engageable with a second closure portion of a base such that when the first and second closure portions are engaged with one another, the first cover and the base define a substantially sealed storage area; and

a second cover including a first closure portion, an engagement portion and an alignment portion,

wherein a plurality of adjacent and stacked lids forming a vertically aligned lid stack are configurable into a first locked configuration and a second unlocked configuration, wherein:

the engaging portion of the first cover includes an upper projection and is engageable with an engaging portion of the second cover; wherein the second cover includes a lower protrusion; and, in the first locking configuration, the lower projection fits over and receives the upper projection to lock the two covers together;

in a second, non-locking configuration, the alignment portion of the first lid is engageable with the alignment portion of the second lid to form an aligned nested lid stack that is sufficiently robust to prevent longitudinal, lateral, or rotational movement caused by forces typically generated during a manufacturing operation, while allowing nesting of one or more lids in a lid stack to be undone after a given force is applied.

17. The system of claim 16, wherein each of the first cover and the second cover comprises a thermoformed plastic.

18. The system of claim 16, wherein the first closure portion includes a locking ring, the locking ring of the first closure portion including an inner wall, a retaining rim, and an outer wall.

19. The system of claim 16, wherein the first closure portion of the first cover is engageable with the first closure portion of the second cover.

20. The system of claim 16, wherein the engagement portion includes a rib and a detent, and the rib of the engagement portion of the first cover is engageable with the detent of the engagement portion of the second cover.

21. The system of claim 16, wherein the first and second covers comprise a grip tab.

22. The system of claim 16, wherein the alignment portion of the first cap comprises a member selected from the group consisting of a flange, a protrusion, and a locking ring.

23. The system of claim 16, further comprising:

a third cover including a first closure portion, an engagement portion and an alignment portion,

wherein the alignment portion of the third cover is engageable with the alignment portion of the second cover.