EP0454339A1

EP0454339A1 - Double lug reclosable food packages

Info

Publication number: EP0454339A1
Application number: EP91303354A
Authority: EP
Inventors: Francis R. Finn; Drew H. Moore
Original assignee: Oscar Mayer Foods Corp
Current assignee: Oscar Mayer Foods Corp
Priority date: 1990-04-27
Filing date: 1991-04-16
Publication date: 1991-10-30
Also published as: CA2039578A1; JPH04242562A

Abstract

This invention pertains to a reclosable package having a body member (22), a base member (12) having a pedestal, a hermetic seal between the body member and the base member and snap locking structures in the respective sidewalls of the body member and base member. Opposing pairs of snap locking indents/detents (34, 46; 36, 48) are provided on a sidewall (20; 30) of the base pedestal and on an opposing sidewall (40; 44) of a moat-like portion of a tongue-and-groove structure provided in peripheral portions of the body member and base member.

Description

Background of the Invention

Field of the Invention

This invention pertains to a food-package having a base, a body member, a peelable seal for hermetically sealing the base to the cover and opposing snap-locking members contained in the base and in the cover for reclosing the package after it has been opened and for providing an audible snap as the package is reclosed.

Description of the Prior Art

Multiple-component food packages have been described in the past. For example, in U.S. Patent No. 3,498,018, a food package is described wherein the food is sealed inside the package having a body member and a top member. The food is formed under vacuum, and the package is hermetically sealed. These types of packages and methods for forming them are further described in U.S. Patents No. 4,411,122; No. 4,577,757; and No. 4,688,369. Attempts to improve packages of these patents are further described in U.S. Patents No. 4,498,588 and No. 4,498,589. For instance, in U.S. Patent No. 4,498,588, ridges 34 and grooves 36 are described and illustrate an attempt to provide a package having interlocking engagement features.
These elements, however, have not proven to be satisfactory in producing a suitable audible snap in reclosing the package. Other means of incorporating snap actions into packages are described in U.S. Patents No. 3,672,536 and No. 3,734,276. Thus, there remains in the art a need for a package that is easily openable and also recloses in a positive manner by providing an audible sound signifying to the consumer that the package has been reclosed.
With packages that rely primarily on adhesive means for sealing, at times it is difficult to provide a peelable seal which has a desired easy-opening characteristic or to provide that desired easy-opening characteristic with very reliable consistency. Also, adhesives do not substantially enhance the overall rigidity of the package. Accordingly, it would be advantageous to provide a package that does not rely substantially exclusively on adhesives to provide a peelable seal, especially when such a package also exhibits a convenient-to-use and reliable reclosure characteristic that incorporates a snap closure sound.

Brief Description of the Drawings

Figure 1 is a perspective view of a preferred embodiment according to the invention;
Figure 2 is a view of the package of Figure 1, showing a top plan view of the body or bubble member of this package;
Figure 3 is a top plan view of the base member of the package of Figure 1; and
Figure 4 is a cross-sectional view along the line 4-4 of Figure 1.

Summary of the Invention

The invention pertains to a vacuumized, hermetically sealed package having a moat-like structure along the peripheral flange thereof and having opposing lug members. The package includes a base member having centrally positioned pedestal and a channel surrounding the pedestal which is defined by a raised sidewall spaced from the pedestal. Also provided is a package body member having a body bubble and a channel surrounding the bubble, the channel being defined between a generally upstanding sidewall of the bubble and a raised sidewall spaced from the bubble sidewall. The respective sidewalls of the base member and of the body member engage each other in telescoping arrangement, and the sidewall of the base pedestal telescopingly engages a portion of the bubble sidewall. A peelable sealing means is also provided for attaching the base ring panel to the body ring panel, the peelable sealing means being openable with digital pull-apart forces. Reclosable members are provided on respective mating sidewalls of the base member and of the body member. Preferably, the reclosable members are interfering projections or lugs in the sidewalls which engage each other and which can be disengaged by the application of digital forces, when desired. Packages having these features provide a base member and a body member with components which engage each other with an audible closure snapping sound.

Detailed Description of the Invention

U.S. Patents No. 3,498,018, No. 4,411,122, No. 4,577,757, and No. 4,688,369 are herein incorporated by reference. These patents describe a method of forming a vacuumized, hermetically sealed package, characterized by a predetermined quantity of a product which can be deformable and is arranged in the form of an upright mass on a base panel portion on the pedestal of a base.
Regarding the package shown in Figures 1 through 4, its base 12 has a base panel portion 10, a base peripheral flange 14, a generally upstanding base sidewall 16, a base ring panel 18 and a generally upstanding pedestal sidewall 20 which, together with the panel 10, defines the pedestal portion of the base member 12. Another generally upstanding base sidewall 40 cooperates with the sidewall 16 and the ring panel 18 to define a raised wall member, while another base ring panel 38 cooperates with this same sidewall 40 and the pedestal sidewall 20 in order to define a slot member. The thus defined raised wall member and slot member define a moat-like structure that surrounds the pedestal portion. The raised wall member and the slot member of the base 12 are sized and shaped to cooperate with similarly sized and shaped members of a package body 22, discussed in more detail hereinafter.
With reference to the package body 22, it has a body peripheral flange 24, a body sidewall 26 and a body ring panel 28, as well as a bubble sidewall 30 and a body panel portion 32 which form a bubble portion of the body 22. Another body sidewall 44 cooperates with the sidewall 26 and the ring panel 28 to define a slot member, while another body ring panel 42 cooperates with this same sidewall 44 and the bubble sidewall 30 in order to define a raised wall member. This raised wall member and slot member define a moat-like structure which surrounds the bubble portion and which matingly and telescopingly engage the respective raised wall member and slot member of the base 12 in order to provide an overall tongue-and-groove structure by which the base 12 and the body 22 securely engage one another.
More specifically, the base sidewall 16 engages the body sidewall 26 in telescoping arrangement, the base sidewall 40 and body sidewall 44 (which can be identified as being in the moat region) telescopingly engage each other, and the base sidewall 20 and body sidewall 30 (which can be identified as being in the pedestal region) telescopingly engage each other. A peelable sealing means suitable for hermetically vacuum sealing procedures attaches the base ring panel 18 to the body ring panel 28. The peelable sealing means, which can be an adhesive, is openable with digital pull-apart forces which are less than digital pull-apart forces that typically are required for known packages incorporating such peelable sealing means that is not in combination with the other features of the reclosable sealing assemblies of this invention.
Opposing reclosable members are provided on the base and on the body, these reclosable members being interfering projections in sidewalls thereof. In this embodiment, the opposing interfering protections are opposing pairs of indents and detents on generally upstanding sidewalls, one pair being in the moat region and a pair opposing same being in the pedestal region. More specifically, one pair is thin protrusion or raised detent 34 in the pedestal sidewall 20 and indent 36 in the bubble sidewall 30. Its opposing pair is protrusion or raised detent 46 and indent 48 in the respective moat area sidewalls. Each raised detent snaps within its corresponding indent in order to insure a positive securement together of the base 12 and the bubble 22.
To fill the package, the body member 22 is placed in an inverted position, and a sufficient quantity of product is placed in said body member to substantially fill the body member when the package is completed. The base 12 is positioned on the mouth of the body member 22 so that the product panel disposes in a telescopic way into the body member and engages the product to provide a pedestal therefor. The flange margins of the base 12 overlie the corresponding margins of the body member 22. Mechanical pressure is applied inwardly on the outside surface of the raised panel portion. The area defined by the bottom edges of the body side walls is sufficient to force the product into close contact with the interior surfaces of base and body members, which may when desired shape the product to more closely conform to the shape of the interior surface and to substantially completely fill the space between the package and product while vacuumizing the assembly and the sealing of the package by hermetic means.
According to the present invention, reclosable packages are attained by thermoforming one or more continuous rings in the package base and body so as to form the moat-like structure or tongue-and-groove arrangement as shown in the drawings. The base ring or moat wall is high enough (1/16 inch or more [1.6 inch or more]) to allow crimping to form the opposing indents and detents before or after filling and sealing of the package. A one or two step thermoforming and/or crimping of the ring causes an audible snap when the bubble and base are pressed together.
Reclosability and the ability to have the package stay closed are achieved at low cost by providing several points of friction interaction inside or outside the sealed area of the package. An audible snap sound is also enhanced by means of a visible pedestal ring which contributes to the perception of freshness preservation once the package is opened.
A preferred means to achieve a positive reclosable package is to produce matching vertical indented grooves. For example, each matching body groove ring 42 and base groove ring 38 function like a tongue-and-groove lid/container package, and a snap sound is also produced when the parts are pressed together due to their combination with the matched pairs of opposing indents and the raised detents 36, 34 and 48, 46 on the respective opposing sidewalls. The vertical grooved indentation ring preferably is formed directly adjacent to the pedestal sidewall 20 and the corresponding location of the bubble sidewall 30. The groove preferably is 1/8 inch [3.2 mm] wide or wider by 1/8 inch [3.2 mm] deep on the base, with the corresponding dimensions of the groove on the body being slightly less.
With more particular reference to the pairs of opposing indents and raised detents, the package itself is thereby provided with opposing lug formations. One of the lug formations is in the pedestal region of the package, as exemplified by raised detent 34 and its mating indent 36. Opposing lug formation is provided in the moat region, as exemplified by raised detent 46 and its mating indent 48. Both the lug structure in the pedestal region and the lug structure in the moat region are positioned below the base ring panel 18 and the body ring panel 28 and within the groove area adjacent to the pedestal and/or bubble. With this structure, this groove within the package body 22 is under compression when the body and base are assembled. The compressive forces are applied particularly at the interior surfaces of the opposing indents 36 and 48. Correspondingly, the base in the area of the lug formations is under tension when the package is assembled. Forces transmitted generally at the opposing raised detents 34, 46 exert a spreading force on the groove defined by the sidewalls 20 and 40 of the base 12. Thus, the area of the lugs in the bubble is under compression while the area in the lugs of the base is under tension, which causes the lugs or indent/raised pairs to fit securely within each other in order to enhance holding together of the assembled package.
When the package is opened, the lugs in the moat region, namely detent 46 and indent 48, will be disengaged from each other before the opposing detent/indent are disengaged from each other. This stepwise disengagement allows for easier package opening because both disengagements do not have to occur at the same time, which would require a greater opening force. Furthermore, because of the compression/tension aspects of this package, the size and depth of the indents and raised detents can be less than what would otherwise be needed to achieve the same locking strength as is achieved by the structure according to this invention.
These advantages in opening and locking of the finished package also translate to advantages in molding and formation of the package components. When the bubble or the base is being stripped from its forming mold, mold stripping will be facilitated because the moat region indent or detent is removed from the die first, followed by the intent or detent in the pedestal region. Again, this one-at-a-time or two-stage mold stripping procedure means that less force is needed to remove the package component from the mold or die. With the ability to utilize detent/indent sizes and depths that are less than would be otherwise required to achieve a desired locking strength, these smaller indents/detents will be easier to form and will facilitate thermoforming of the package.
These various attributes of a particular structure according to this invention can be further facilitated by specific aspects of the ring-and-groove structure as shown in Figure 4. The base ring panel 18 can include rounded corners as shown, to thereby provide additional clearance during assembly and disassembly of the package components. Also, the generally upstanding sidewalls 20 and 30 can exhibit the inclined configuration illustrated in the drawings. The angle of these sidewalls 20, 30 with respect to the ring panels 38 is illustrated as being slightly greater than 90 degrees, but far short of 180 degrees, thereby facilitating sliding assembly and disassembly of the base and body.
Adhering the two package parts together preferably occurs between ring panels. Sealing may occur by using adhesive, by using multilayered oxygen barrier heat sealable films, or by using an adhesive gasket. The sealing component such as an adhesive may be applied to the top of the base ring panel 18, to the undersurface of the body ring panel 28, to the top of the base ring panel 38, or to the undersurface of the body ring panel 42 (Figure 4). Even though the seal thus produced is readily peelable by digital forces, the grooved channel aspect of the invention enhances the idea that the package is resealed once it is opened.
Also, the projections of the package are visible to the consumer, and they present a pleasing appearance. To achieve easy opening, high molecular weight polymer adhesives which are peelable/resealable may be used, or easy-peel, multilayer rigid films that are heat sealable may be used. Accordingly, features of this invention include thermoforming projections in the body member and base which are part of the side walls that friction-fit through a pinching action (top to bottom) with or without a post-thermoforming gripping action when the base and body member are pressed together. The post-thermoforming gripping action would be accomplished by using a heated device to augment the depth of the matched rings or ring width dot projections to achieve a greater interference fit. Solid state is another means to achieve augmented depth.
A benefit of the grooved sealing components in the present packaging is enhanced wall strength and rigidity when compared with that of similar packages that do not include these types of grooved sealing components. Thinner sheet stock can be used, particularly for the base component or for the body component when its bubble is relatively shallow. The thickness of the body member is between approximately 8 and 13 1/2 mil (between approximately 0.20 and 0.34 mm), and the thickness of the base is between approximately 8 and 10 mil (between approximately 0.20 and 0.25 mm). The body member composition may be Barex 210, a polyester, PET or PVC. The base composition suitably is Barex 210, a polyester, PVC, Saranex laminated to Barex 210, PVC, or polystyrene.
Packages according to this invention can have generally rectangular or square shapes, such as shown in Figures 1 through 4. Alternatively, they can have generally circular-shaped pedestals and bubbles, or they can be otherwise shaped as desired.
Whatever adhesive means or snap groove means are utilized, the combination of the present invention provides an advantage of easier peelability when compared with similarly sized packages which incorporate only an applied peelable adhesive for forming the peelable seal. Because a substantial proportion of the seal and reclosure properties of the package are provided by non-adhesive means, including the body groove compression and base groove tension at the opposing indent/detent pairs, the seal adhesion strength provided by the present adhesive means need not be as great as when the adhesive alone provides substantially all of the seal strength. For example, the present adhesive means can have an application width that is approximately one-half of the adhesive width provided in prior packages to keep the package securely sealed during commercial distribution and handling. Also, by combining the adhesive means with the tongue-and-groove arrangement, well-defined locations for confining the location of the adhesive means are provided within the groove of the base and/or body. This provides an especially neat appearance to the adhesive means, and even when the adhesive gasket approach is not utilized, there is less of a likelihood that the adhesive will exhibit stringiness primarily because the adhesive can be applied more thinly and with reduced surface area.
It will thus be seen that the present invention provides new and useful packaging having tongue-and-groove means, which packaging has a number of advantages and characteristics, including those pointed out herein and others which are inherent in the invention. Preferred embodiments of the invention have been described by way of example, and it is anticipated the modifications may be made to the described form without departing from the spirit of the invention or the scope of appended claims.

Claims

A food package comprising:
(a) a base member having an upstanding pedestal including a pedestal panel portion and a pedestal sidewall, said base member including a slot portion peripheral of and substantially adjacent to at least a portion of said pedestal sidewall, said base member further including a generally upstanding ring portion substantially adjacent to said slot portion of said base member, whereby said slot portion is generally between said pedestal sidewall and said ring portion;

(b) a body member having an upstanding bubble including a bubble panel portion and a bubble sidewall, said body member including a generally upstanding ring portion and a slot portion so as to provide the body member with structures complementary in shape and size and matingly engageable with said respective slot portion and generally upstanding ring portion of the base member, whereby a general tongue-and-groove assembly structure is provided by said ring portion and slot portion of said base member and by said slot portion and ring portion of said body member when said base member and body member are in generally telescoping engagement with each other;

(c) sealing means for attaching said base member to said body member with a peelable seal that is hermetic, suitable for vacuum packaging and openable with digital pull-apart forces, said sealing means being within said tongue-and-groove assembly; and

(d) means for reclosing the food package by engaging a portion of said base member with a portion of said body member, said reclosing means including opposing pairs of interfering projections, one said pair of interfering projections being in said pedestal sidewall and said bubble sidewall, and an opposing said pair of interfering protections being in base member and body member sidewalls within the tongue-and-groove assembly structure.
The food package according to claim 1, wherein said opposing pairs of interfering protections are substantially directly opposite to each other at a height within a moat area of the tongue-and-groove assembly structure.
The food package according to claim 1, wherein said interfering projections of the body member are under compression and wherein said interfering projections of the base member are under tension when the base member and body member are assembled together.
The food package according to claim 1, wherein said interfering projection pairs are a complementarily shaped indent and a raised detent.
The food package according to claim 1, wherein said generally upstanding ring portion of the base member has an upstanding edge which is generally rounded.
The food package according to claim 1, wherein said pedestal sidewall is tapered in a direction from said slot portion of the base member to said pedestal panel portion.