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Title:
MULTI-CAVITY PRESSED PAPERBOARD FOR UNIT PACKAGING
Document Type and Number:
WIPO Patent Application WO/2010/132260
Kind Code:
A1
Abstract:
One embodiment of the disclosure describes a packaging blank. The packaging blank may include a paperboard card and an array of raised sections. The paperboard card may define a card surface. With respect to the array of raised sections, each raised section may be formed in the paperboard card and remain connected thereto. Each raised section may at least partially define a cavity extending above the card surface. The blister pack may be mounted with the blank and may have at least one unit dose associated therewith. Each unit dose may be positioned relative to a corresponding raised section of a given blank so as to extend into a respective cavity associated with a given raised section.

Inventors:
GELARDI JOHN A (US)
MULLEN DANA (US)
Application Number:
PCT/US2010/033807
Publication Date:
November 18, 2010
Filing Date:
May 06, 2010
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
MEADWESTVACO CORP (US)
GELARDI JOHN A (US)
MULLEN DANA (US)
International Classes:
B65D75/32; B65D75/36
Foreign References:
US20030234203A12003-12-25
US5339960A1994-08-23
EP0847921A11998-06-17
USPP98427407P2007-10-31
Attorney, Agent or Firm:
SCHEIDLER, Alison et al. (1021 Main Campus DriveRaleigh, North Carolina, US)
Download PDF:
Claims:
What is claimed:

1. A packaging blank, comprising: a paperboard card with a card surface; and an array of raised sections, each raised section being formed in the paperboard card and remaining connected thereto, each raised section at least partially defining a cavity extending above the card surface.

2. The packaging blank of claim 1, wherein at least one given raised section is at least one of a structural support element and a protective covering for a product contained within the cavity.

3. The packaging blank of claim 1, wherein at least one given raised section defines a child- resistant tear feature.

4. The packaging blank of claim 3, wherein the child-resistant tear feature includes a tear- initiation opening.

5. The packaging blank of claim 4, wherein the paperboard card has at least one card edge, the paperboard card including at least one child-resistant tear perforation therein, a given child-resistant tear perforation extending between a respective card edge and a corresponding raised section having a given child-resistant tear feature.

6. The packaging blank of claim 1, comprising a first raised section and a corresponding second raised section, the first raised section being configured for covering a product, the corresponding second raised section being configured for serving as a tear-initiation feature to reach the product covered by the first raised section.

7. The packaging blank of claim 1, wherein a given raised section has printed indicia thereon, the printed indicia corresponding to a product contained within the cavity.

8. The packaging blank of claim 1, wherein the paperboard is comprised of a self-sealable paperboard material.

9. The packaging blank of claim 1, wherein the paperboard is comprised of a solid bleached sulfate paperboard material.

10. The packaging blank of claim 1, wherein a given raised section has a section perimeter, the section perimeter including an attached perimeter portion and a cut perimeter portion, the attached perimeter portion being integral with the paperboard card, the cut perimeter portion being detached therefrom.

11. The packaging blank of claim 1 , wherein the array of raised sections forms an array of at least one dimension.

12. The packaging blank of claim 11, wherein the array of raised sections defines a two- dimensional array.

13. The packaging blank of claim 1, wherein at least one adjacent pair of raised sections are distinctly spaced from one another.

14. The packaging blank of claim 13, wherein at least one given adjacent pair of raised sections are spaced within about one inch of one another.

15. The packaging blank of claim 1, wherein each raised section includes at least one tab portion.

16. The packaging blank of claim 15, wherein at least one raised section includes a plurality of tab portions.

17. A method of making a packaging blank, the method comprising the steps of: providing a paperboard card having a card surface; providing a two-piece mold for pressing at least one product cavity in the paperboard blank, the two-piece mold comprising a male mold element and a female mold element; placing the paperboard card between the male mold element and the female mold element; and

forming the paperboard card using the male mold element and the female mold element, thereby yielding at least one raised section in the paperboard card and remaining connected thereto, each raised section at least partially defining a cavity extending above the card surface.

18. The method of claim 17, further comprising the step of providing at least one perforation in the paperboard card prior to placing the paperboard card between the male mold element and the female mold element, a respective perforation being created in the paperboard card at a position relative to a location where a given raised section is to be formed, the respective perforation allowing the given raised section to be at least partially dislocated from at least one of the paperboard card and an adjoining raised section.

19. A package, comprising: at least one blank, each blank including: a paperboard card with a card surface; and at least one raised section, each raised section being formed in the paperboard card and remaining connected thereto, each raised section at least partially defining a cavity extending above the card surface; and a blister pack mounted with the at least one blank, the blister pack having at least one unit dose associated therewith, each unit dose being positioned relative to a corresponding raised section of a given blank, each unit dose extending into a respective cavity associated with a given raised section.

20. The package of claim 19, wherein at least one given raised section is at least one of a structural support element and a protective covering for a product contained within the cavity.

21. The package of claim 19, wherein at least one given raised section defines a child- resistant tear feature.

22. The package of claim 19, wherein the child-resistant tear feature includes a tear-initiation opening.

23. The package of claim 22, wherein the paperboard card has at least one card edge, the paperboard card including at least one card tear perforation therein, a given card tear perforation extending between a respective card edge and a corresponding raised section having a given child-resistant tear feature.

24. The package of claim 19, comprising a first raised section and a corresponding second raised section, the first raised section being configured for covering a product, the corresponding second raised section being configured for serving as a tear-initiation feature to reach the product covered by the first raised section.

25. The package of claim 19, wherein a given raised section has printed indicia thereon, the printed indicia corresponding to a product contained within the cavity.

26. The package of claim 19, wherein the paperboard card is comprised of a self-sealable paperboard material.

27. The package of claim 19, wherein the paperboard card is comprised of a solid bleached sulfate paperboard material.

28. The package of claim 19, wherein a plurality of the raised sections are provided.

29. The package of claim 28, wherein the plurality of the raised sections define an array of the raised sections.

30. The package of claim 29, wherein the array of the raised sections defines a two- dimensional array.

31. The package of claim 28, wherein at least one adjacent pair of raised sections are distinctly spaced from one another.

32. The package of claim 31, wherein at least one given adjacent pair of raised sections are spaced at most about one inch from one another.

33. The package of claim 19, wherein a given raised section has a section perimeter, the section perimeter including an attached perimeter portion and a cut perimeter portion, the attached perimeter portion being integral with the paperboard card, the cut perimeter portion being detached therefrom.

34. The package of claim 33, wherein a given raised section, due to the cut perimeter portion thereof, opens in a given direction, with the attached perimeter portion forming a pivot connection with the paperboard card.

35. The package of claim 34, comprising a first blank and a second blank, the first blank being positioned between the blister pack and the second blank, each given raised section of the first blank being oriented so as to open in a first direction, each given raised section of the second blank being oriented so as to open in a second direction opposite to the first direction.

36. The package of claim 35, wherein a pair of raised sections is associated with a given cavity, the pair of raised sections being configured for forming an interlocking connection with one another.

37. The package of claim 19, wherein the blister pack comprises a foil backing and a plastic blister, the plastic blister including at least one unit dose site, each unit dose site being configured for receiving a given unit dose therein.

38. The package of claim 37, wherein the plastic blister is formed of a flexible thin film of plastic.

39. The package of claim 38, wherein the flexible thin film of plastic and each blank are pressed in such a manner that a position and a size of each respective unit dose site directly corresponds to that of a given raised section.

40. The package of claim 37, wherein the foil backing is provided with at least one area of weakness, each respective area of weakness being associated with a corresponding unit dose site.

41. The package of claim 37, further comprising an encasing panel, the encasing panel having a central panel portion and at least one side panel portion, the central panel portion having at least one receiving hole therethrough, each receiving hole respectively receiving a corresponding raised section therethrough, each side panel respectively folding from a given side of the central panel portion, the card surface of a given paperboard card contacting the central panel portion the blister pack being sandwiched between a given blank and a folded side panel.

42. The package of claim 41, wherein the encasing panel includes two side panel portions, each side panel respectively folding from an opposed side of the central panel portion.

43. The package of claim 42, wherein at least one given raised section defines a child- resistant tear feature, the child-resistant tear feature including a tear-initiation opening, the paperboard card having at least one card edge, a given side panel folding relative to a corresponding card edge, the paperboard card including at least one card tear perforation therein, a given card tear perforation extending between a respective card edge and a corresponding raised section having a given child-resistant tear feature, the encasing panel having at least one panel tear perforation defined therein, the central panel portion including at least one first receiving hole configured for receiving a corresponding raised section having a given child-resistant tear feature therein, each panel tear perforation respectively extending from a first position proximate a given first receiving hole to a second position within an adjacent side panel portion, the second position within the adjacent side panel portion corresponding to a location of a given unit dose.

44. The package of claim 19, wherein each raised section includes at least one tab portion.

45. The package of claim 44, wherein at least one raised section includes a plurality of tab portions,

RECTIFIED SHEET (RULE 91) ISA/EP

Description:
MULTI-CAVITY PRESSED PAPERBOARD FOR UNIT PACKAGING

BACKGROUND

[0001] The present invention relates to uses for pressed paperboard defining at least one cavity and, in particular, to the use of multi-cavity pressed paperboard in unit packaging. [0002] Unit dose packaging is an attractive packaging format for certain pharmaceutical applications because it is convenient, yet sturdy enough to be handled numerous times until the course of medication is completed, and also enables the user to track the consumption of doses according to the prescribed schedule. The typical unit dose packaging incorporates a plastic blister. The plastic blister generally defines a plurality of cavities in which individual pills or other products are contained. As part of its role in containing such pills or products, the plastic blister has needed to be able to provide structural support in order to protect such pills or products. For sustainability reasons, however, it would be desirable to reduce the reliance on plastic in packaging and relying more on paperboard.

SUMMARY

[0003] One embodiment of the disclosure describes a packaging blank. The packaging blank may include a paperboard card and an array of raised sections. The paperboard card may define a card surface. With respect to the array of raised sections, each raised section may be formed in the paperboard card and remain connected thereto. Each raised section may at least partially define a cavity extending above the card surface.

[0004] Another embodiment of the disclosure describes a package. The package includes at least one blank and a blister pack. Each blank may include a paperboard card and at least one raised section. The paperboard card may define a card surface. Each raised section may be formed in the paperboard card and remain connected thereto. Each raised section may at least partially define a cavity extending above the card surface. The blister pack may be mounted with the at least one blank and may have at least one unit dose associated therewith. Each unit dose may be positioned relative to a corresponding raised section of a given blank so as to extend into a respective cavity associated with a given raised section.

BRIEF SUMMARY OF THE DRAWINGS

[0005] FIG. 1 illustrates a top perspective view of a packaging blank, according to one embodiment of the disclosure;

[0006] FIG. 2 illustrates a top perspective view of a packaging blank, according to another embodiment of the disclosure;

[0007] FIG. 3 shows a top perspective view of a packaging blank, according to yet another embodiment of the disclosure;

[0008] FIG. 4 shows a top, schematic layout for a 2-piece paperboard wallet card, employing the packaging blank of FIG. 3;

[0009] FIG. 5 illustrates a top perspective view of a pressed thin-film plastic used in a blister pack, according to one embodiment of the disclosure;

[0010] FIG. 6 is a side, schematic view of a blister pack, incorporating the pressed thin-film plastic of FIG. 5, according to one embodiment of the disclosure;

[0011] FIG. 7 illustrates a top perspective view of a 2-piece wallet card of another embodiment, incorporating the two paperboard card pieces of FIG. 4 and the blister pack of FIG. 6;

[0012] FIG. 8 shows a top perspective view of a wallet card of one embodiment, incorporating the packaging blank of FIG. 1 and the blister pack of FIG. 6; [0013] FIG. 9 shows a top perspective view of another embodiment of a wallet card, incorporating two pressed packaging blanks;

[0014] FIG. 10 illustrates a two-piece mold for pressing and forming a given packaging blank and a corresponding thin- film plastic;

[0015] FIG. 11 shows a top view of a packaging blank, according to yet another embodiment of the disclosure; and

[0016] FIG. 12 illustrates a top view of yet another embodiment of a wallet card, incorporating two pressed packaging blanks with interlocking portions.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0017] Referring to FIG. 1, a packaging blank 20a, according to one embodiment of the disclosure, may include a paperboard card 22 and at least one primary pressed, raised section 24, of which an array of such primary raised sections 24 is shown.

[0018] The paperboard card 22 may define a card surface 26 and may be made of any of a variety of paperboard materials. For example, the paperboard card may be made of a self- sealable paperboard material, a Kraft paperboard material, or a solid bleached sulfate paperboard material. The self-sealable paperboard material particularly facilitates attachment to other elements of a package, without necessarily having to provide a further adhesive. [0019] Each primary raised section 24 may be formed in the paperboard card 22 by a pressing operation (to be discussed later) and remain connected thereto. Each primary raised section 24 may at least partially define a cavity 28 extending above the card surface 26. At least one such primary raised section 24 may serve as at least one of a structural support element and a protective covering for a product (e.g., a unit dose) contained within the corresponding cavity 28. A given primary raised section 24 may further have indicia 30 (e.g., numbers, letters, days of week, etc.) printed thereon, the printed indicia 30 corresponding to a product (not shown) contained within the corresponding cavity 28. [0020] Each primary raised section 24 may define an attached perimeter portion 32 and may further include a cut or detached perimeter portion 34. The attached perimeter portion 32 may, in particular, remain integrally attached to the paperboard card 22, throughout formation thereof and during use. A cut or detached perimeter portion 34 may provide stress relief during pressing, thereby helping to avoid concurrent tearing of the attached perimeter portion 32.

[0021] There may be a plurality of primary raised sections 24 formed in a given paperboard card 22, and such primary raised sections 24 further may define an array. The array may have at least one dimension, of which two are shown in FIG. 1. As further seen from FIG. 1, adjacent primary raised sections 24 may be distinctly spaced from one another. While maintaining distinct spacing, such adjacent primary raised sections 24 may still be spaced, for example, less than about one inch of one another. Additionally, the size of given primary raised section 24 may be chosen based upon the function thereof and/or the cavity size to be associated therewith. Use of a stress relief cut (e.g., a cut or detached perimeter portion 34) permits a given raised section to include at least one smaller radius of curvature (e.g., less than about one inch and even less than about one-half inch). The arraying of primary raised sections 24 and the control of the spacing and size thereof may, together or alone, help facilitate efficient use of the available card area.

[0022] Another embodiment is illustrated in FIG. 2, with similar parts as FIG. 1 being labeled alike. In particular, a packaging blank 20b of a second embodiment may include a paperboard card 22; at least one primary pressed, raised section 24, of which an array of such primary raised sections 24 is shown; and at least one secondary pressed, raised section 36, of which an array thereof are shown.

[0023] Each secondary raised section 36 may, as per the embodiment shown in FIG. 2, define a child-resistant tear feature. Specifically, each secondary raised section 36 may be positioned proximate a corresponding primary raised section 24 and may have an arcuate opening 38 extending thereacross (e.g., over the top and nearly diametrical). Like the cut perimeter portion 34 of a given primary raised section 24, a given arcuate opening 38 may act as a stress relief mechanism during press formation of a corresponding secondary raised section 36. However, each arcuate opening 38 also may serve as a tear-initiation opening as part of a child-resistant tear feature. Because the arcuate opening 38 may be raised above the card surface 26, it may be easier for an adult with limited coordination (e.g., a senior citizen) to grip the open portion with, e.g., a fingernail to begin a tear.

[0024] The paperboard card 22 may have at least one card edge 40 and at least one child- resistant tear perforation 42 therein. A given secondary raised section 36 is located between a corresponding primary raised section 24 and a nearest card edge 40. Each child-resistant tear perforation 42 may extend between a given secondary raised section 36, being used as a child-resistant tear feature, and the nearest card edge 40. It is to be understood that a perforation may, for example, include a series of spaced cuts, a line of reduced thickness, etc., that promotes directional tearing. Further, a pair of child-resistant tear perforations 42 may be associated with each given secondary raised section 36, each one respectively extending from diametrical sides of that given secondary raised section 36. A given arcuate opening 38 and the related pair of child-resistant tear perforations 42 together facilitate tearing from a given secondary raised section 36 to a nearest card edge 40. In particular, a given secondary raised section 36 may be configured for serving as a tear-initiation feature to reach the product covered by the corresponding primary raised section 24, as will discussed more later.

[0025] A further embodiment is shown in FIG. 3, in which parts similar to those provided in FIG. 2 are labeled alike. In particular, a packaging blank 20c of a third embodiment of the packaging may include a paperboard card 22; at least one primary pressed, raised section 24, of which an array of such primary raised sections 24 is shown; and at least one secondary pressed, raised section 36, of which an array thereof are shown.

[0026] With the packaging blanks 20a and 20b, each primary raised section 24 may be considered to be essentially a single tab element. However, each primary raised section 24 of the packaging blank 20c may be defined by a plurality of raised tabs 44, acting together. The plurality of raised tabs 44 of a given primary raised section 24 may be the result, for example, of first making a series of cuts and/or one composite cut and then press-molding the packaging blank 20c to yield such raised tabs 44. In the illustrated example, an I-shaped gap 46 may be defined between a related set of raised tabs 44. Thus, in the packaging blank 20c, the raised tabs 44 may be considered to be connected at attached perimeter portion 32, similar to the packaging blanks 20a and 20b. However, unlike the packaging blanks 20a and 20b, the cut or detached portion (e.g., the I-shaped gap 46) may be defined within the interior of a given primary raised section 24. It is, however, to be understood that multiple raised tabs 44 could be created wherein at least one raised tab 44 has a cut or detached portion that is effectively a detached perimeter portion 34 (i.e., extending from one side of a primary raised section 24 to another).

[0027] As per FIG. 4, a two-piece paperboard support 48 for a wallet card may include a given packaging blank 20b, 20c (of which 20c is shown) and an encasing panel 50. Further, from FIGS. 5 and 6, a blister pack 52, including a plastic blister 54 and a foil backing 56, may be seen. The encasing panel 50 may be particularly configured for sealing the interior portions (e.g., a given blank 20b, 20c, and the corresponding blister pack 52) of a given wallet card together.

[0028] The encasing panel 50 may have a central panel portion 58 and at least one side panel portion 60, of which two such side panel portions 60 are shown. The central panel portion 58 may have at least one receiving hole 62 therethrough. Each receiving hole 62 respectively may receive a correspondingly sized and positioned one of a primary or secondary raised section 24, 36 therethrough (FIG. 7), as per one embodiment of an assembled first wallet card 64. Each side panel 60 may respectively fold from a given side of the central panel portion 58, along a given panel fold 66. In the illustrated embodiment, the encasing panel 50 includes two side panel portions 60, with the side panels 60 respectively being foldable (e.g., approximately 180°) relative to the opposed sides of the central panel portion 58 and into contact with the foil backing 56 of the blister pack 52.

[0029] The card surface 26 of a given paperboard card 22 may contact the central panel portion 58 and may further be adhered thereto (e.g., via an adhesive and/or use of a self- adhesive paperboard material). The blister pack 52 may be sandwiched between a given packaging blank 20b, 20c and a folded side panel 60. In particular, the foil backing 56 of the blister pack 52 may face and, more particularly, contact a given folded side panel 60. The use of an adhesive and/or the use of a self-adhesive paperboard material for the encasing panel 50 may, for example, be employed to ensure that a sealed wallet card 64 may be produced.

[0030] The encasing panel 50 may further have at least one panel tear perforation 68 defined therein. The central panel portion 58 may particularly include at least one first receiving hole 62a configured for receiving a corresponding secondary raised section 36, which may have a given child-resistant tear feature (e.g., arcuate opening 38) therein. Each panel tear perforation 68 may respectively extend from a first panel position 70 proximate a given first receiving hole 62a, beyond a given panel fold 66, and to at least a second panel position 72 within an adjacent side panel portion 60. The second panel position 72 within the adjacent side panel portion 60 corresponds to a location of a given unit dose. As such, a tear initiated at a given secondary raised section 36 at the front of a first wallet card 64 may be completed at the back thereof proximate the location of a corresponding unit dose. Since the tear may expose the foil backing 56 proximate the unit dose, it may thereby be possible to readily express the given unit dose therethrough. Each tear location/strip may, for example, include a parallel pair of panel tear perforations 68, with such panel tear perforations 68 extending from diametrically opposed positions of a given secondary raised section 36. The concept of a child-resistant tear feature can also be found in commonly-assigned U.S. Provisional Application 60/984,274, filed October 31, 2007.

[0031] The blister pack 52, as per FIGS. 5 and 6, may employ a thin plastic film 74 for the plastic blister 54, instead of a thicker plastic typically provided for a blister pack 52. Such a thin plastic film 74 may be readily formed using a press mold, in a similar manner to that used in making the packaging blank 20a, 20b, 20c. Upon pressing, the thin plastic film 74 may have at least one blister site 76 formed therein. Each blister site 76 may particularly provide a storage location (e.g., a unit dose site) for a given product. Also, the thin plastic film may offer a more sustainable option, allowing less material to be used in making a given blister pack 52. The use of a flexible thin plastic film may be made feasible by the protective nature of the primary raised sections 24. That is, by using the primary raised sections 24, the plastic blister 54 need not necessarily act as structural protection for the unit doses carried thereby. It is understood that, while a thin plastic film may be used for the plastic blister 54, plastic materials typically incorporated in blister packs may instead be used (i.e., typical blister packs could be employed).

[0032] A second wallet card 78 may be seen in FIG. 8. The second wallet card 78 incorporates a packaging blank 20a, a blister pack 52, and an encasing panel 80. The encasing panel 80 may be considered to a simpler version of the encasing panel 50 (e.g., without accommodating the tear features). In the case of the encasing panel 80, potentially one side panel portion (not illustrated) may be used, with that side panel portion covering the entire foil backing 56 of the blister pack 52. Although not shown, the side panel portion may have areas of weakness (e.g., perforations) therein that correspond to the product (e.g., unit dose) locations of the blister pack 52 to permit expression of a given product therethrough. [0033] A third wallet card 82, as seen in FIG. 9, may incorporate packaging blanks 20a and 20b; an encasing panel 50; and a blister pack 52 (not readily seen). Each of these elements may function in the manner previously discussed. One distinguishing feature of the third wallet card 82 may be the use of two overlapping packaging blanks 20a and 20b. Specifically, a first one of the packaging blanks 20a and 20b may oriented relative to the central panel portion 58, with the primary raised sections 24 opening in a first direction. Then, the other one of the packaging blanks 20a and 20b may be positioned against the first one such that the primary raised sections 24 thereof open in a second direction opposite the first direction. As a result, a pair of oppositely-directed primary raised sections 24 may co- act to provide a greater degree of protection for a given product (e.g., a unit dose) stored within a related cavity 28.

[0034] A two-piece mold assembly 84 may be provided for pressing at least one product cavity 28 in the paperboard card 22 and/or the thin plastic film 74. The two-piece mold assembly 84 may include a male mold element 84 and a female mold element 86. The male mold element 84 and the female mold element 86 may, in particular, cooperate to form at least one mold site 90. Each mold site 90 may, for example, be configured for press-forming either a primary raised section 24 or a secondary raised section 36 in a given paperboard card 22. Further, those mold sites 90 used to form the primary raised sections 24 may also be used to mold the blister sites 76 in the thin plastic film 74. To aid alignment of the male and female mold elements 84, 86, alignment features (not labeled), such as a tab/slot combination and/or a post/hole, may be provided.

[0035] The embodiment illustrated in FIG. 11 is similar to that of FIG. 2, with similar parts being labeled alike. In particular, a packaging blank 2Od of a this embodiment may include a paperboard card 22; at least one primary pressed, raised section 24, of which an array of such primary raised sections 24 is shown; and at least one secondary pressed, raised section 36, of which an array thereof are shown. Each primary raised section 24 further may have a lock notch 92 defined therein and thereby further provide a first lobe 94 and a second lobe 96. As can be seen with respect to FIG. 12, the lock notch 92, first lobe 94, and second lobe 96 together permit interlocking with another similarly configured primary raised section 24. [0036] The fourth wallet card 98 shown in FIG. 12 is similar to the third wallet card 82 illustrated in FIG. 9. However, a pair of the packaging blanks 2Od may be used, instead of the packaging blanks 20a and 20b. As with the third wallet card 82, the packaging blanks 2Od are oppositely oriented so that a respective pair of primary raised sections 24 open toward one another. In this embodiment, the lock notches 92 of the adjoining primary raised sections 24 matingly fit and facilitate a lock fit. A lock fit may particularly be achieved matching adjoining notches 92, having one of a first or second lobe 96, 98 of one of the adjoining primary raised sections 24 be on top of the adjacent first or second lobe 96, 98 of the other adjoining primary raised section 24, and having the other of the first or second lobe 96, 98 of the same one of the adjoining primary raised sections 24 be below the adjacent first or second lobe 96, 98 of the other adjoining primary raised section 24. It is to be understood that any configuration that could yield an interlocking fit between an adjoining set of primary raised sections 24 could be used within the context of this embodiment.