Background of the Invention
[0001] The present invention is a continuation-in-part of the application entitled: "Method
of Extending Shelf Life of A Comestible Product while Providing A Locally Packaged
Appearance", Serial No. 08/087,602, filed on July 2, 1993 submitted herewith, the
disclosure of which is incorporated by reference herewith, and related generally to
packaging primarily for comestible products, and more particularly to a relcoseable
clamshell package having novel corner locking features engageable between the container
portion and the lid portion thereof and suitable for providing a recloseable package,
which package may be a modified atmosphere package having strippable opening means.
[0002] In the prior art, consumers have found that recloseable packages are desirable, particularly
for comestible products, and in some embodiments especially in regard to bakery products,
such as muffins, croissants and other freshly baked bakery goods, such as may be typically
provided in a large grocery supermarket which has a bakery on the premises. Packaging
provided for such bakery goods has often been in the form of clear plastic clamshell
packaging. Such clear plastic clamshell packaging, and especially for such bakery
goods, provides a baked-on-the-premises image which grocery retailers have found to
be especially appealing to consumers.
[0003] It has also been deemed desirable in regard to such clear plastic clamshell packaging
to develop recloseability features which are reliable and easy to operate, and especially
in circumstances where more than one serving of a comestible product is contained
therewithin, in order to reduce drying out or other deterioration of the comestible
food product contained therewithin.
[0004] Accordingly, and in view of certain deficiencies of the prior art teachings, it is
a material object of the improved recloseable clamshell package of the present invention
to provide easy to operate means for reclosing a clamshell-type package.
[0005] It is a yet further object of the improved clamshell package of the present invention
to provide a recloseability mechanism having mutually engageable corner disposed detent
or distention mechanisms for positive manual engagement upon opening and relcosing
of the package, and also used for automatic insertion of the lid onto the base by
means of machine application.
[0006] It is a yet further object of the recloseable clamshell package of the present invention
to provide such recloseability features in conjunction with a clamshell package which
has easy operable and strippable opening means for opening such a package, which may
be a modified atmosphere package.
Summary of the Invention
[0007] The present invention is directed to a modified atmosphere clamshell package, having
lockable halves, and further incorpor- ating in preferred embodiments an easy to open
strip. Such modified atmosphere clamshell package includes a hermetic enclosure mechanism,
and further includes bottom disposed bellows-like structures to maintain equal inner
and outer pressures to utilize partial pressure differential means for reducing stresses
on the package seal.
[0008] The recloseable clamshell package of the invention includes a container portion and
a lid portion. The lid portion has a lip portion which is congruently shaped with
the container lip portion for mating engagement therewith in order to form a closed
package. The lid portion includes corner portions which are congruently shaped with
at least a portion of the container portions for mating engagement therewith.
[0009] The present invention is more particularly directed to congruently shaped lid locking
and matingly engageable container and lid distentions disposed on each of the container
lip and container lid lip elements and respective at each of the container portions
and lid corner portions. The congruently shaped container and lid distentions have
slightly different dimensions to exert an engagement force therebetween when engaged.
such congruently shaped and lid locking and matingly engageable container and lid
distentions are in one preferred embodiment substantially arcuate in shape (as determined
in the plain of cross-section which is parallel with the plane with the respective
lip portion).
Brief Description of the Drawing
[0010] In the accompanying drawing, wherein common numerals are utilized with common elements,
the presently inventive recloseable clamshell package of the present invention is
depicted, and wherein:
Fig. 1 is a perspective view from a slightly bottom perspective of a recloseable clamshell
package, which may be a modified atmosphere package, having a package container portion
and a package lid portion, each of which includes in the embodiment of Fig. 1 a sealing
flange thereon for overlapping and sealing disposition therebetween, and illustrating
at the upper corner of the container portion the substantially arcuate shaped distention
for locking with a congruently shaped distention of the lid portion of the container;
Fig. 2 is a slightly enlarged cross-sectional view taken along line 2--2 of Fig. 1
and showing the sidewalls of the container including a reinforced portion of the sidewall
of the lid portion of the package and the package bottom and depicting a package bottom
panel in retracted disposition, which is an additional feature of the package of the
present invention as set forth in an accompanying patent application;
Fig. 3 is a slightly enlarged side view corresponding to that in Fig. 2 and showing
the retractable bottom panel feature in non-retracted configuration, which is a feature
of the recloseable clamshell package as set forth and claimed in a separate patent
applications;
Fig. 4 is a greatly enlarged cross-sectional view taken along lines 4--4 of Fig. 1
and showing a transverse cross-sectional view of the corner of the recloseable clamshell
package including showing the engagement between the container portion and the lid
portion at such corner to illustrate the respective congruently distentions. the
improved recloseable clamshell package of the present invention may be better understood
with regard to the following detailed description of preferred embodiments.
Fig. 5 a cross-sectional view showing an alternative embodiment similar to that of
Fig. 4, and in particular showing a transverse cross-sectional view of the corner
of such alternative embodiment of a recloseable clamshell package, wherein the congruently
shaped lid locking and matingly engageable container and lid distentions have the
lid distention fittingly disposed over the container distention; and
Fig. 6 is a cross-sectional view of the container flange and the lid flange wherein
an indentation is disposed therein for ease of peel comprising a line of reduced strength,
which may be formed, such as for example by a heat sealing bar to assist in stripping
and removing a portion of the lid flange.
Detailed Description of Preferred Embodiments
[0011] Referring now to the drawing, and wherein a recloseable clamshell package generally
10 is set forth, the various elements thereof are depicted.
[0012] In particular, the recloseable clamshell package of the present invention includes
a container portion 12. The container portion 12 includes a bottom element 14 and
connected sidewalls 16,18,20,22 which are connected to bottom 14 and project upwardly
therefrom. The sidewalls 16,18,20,22 are connected together at their respective lateral
edges to form container corners 24,26,28,30. Together, the sidewalls 16,18,20,22 form
a container lip portion 32 which is disposed at the upper extremities of the connected
sidewalls 16,18,20,22 and unitarily extends along the top portion of each such sidewalls
16,18,20,22 and each container corner 24,26,28,39.
[0013] The clamshell package 10 of the present invention further includes a lid portion
34 which has a lid lip portion 36 substantially congruently shaped with at least a
portion of the container lip portion 32 for mating engagement therewith. Together
the lid lip portion 36 and container lip portion 32 form a closeable and recloseable
package. The lid portion 34 includes lid corner portions 38,40,42,44 which are congruently
shaped with the container corners 24,26,28,39 for mating engagement therewith.
[0014] The recloseable clamshell package 10 of the present invention particularly includes
respective congruently shaped lid locking and matingly engageable container and lid
distentions respectively 46,48 which are disposed respectively on the container lip
32 and the lid lip 36 respectively at each of the container corner portions 2,26,28,30
and the lid corner portions 38,40,42,44. The congruently shaped container and lid
distentions 46,48 have slightly different dimensions to assert an engagement force
therebetween when engaged. The congruently shaped lid locking and matingly engageable
container lid lip distentions 46,48 are substantially arcuate shaped in a preferred
embodiment, as set forth in Fig. 4 hereof, as shown in the plane of cross-section
which is parallel with the plane of the respective lip portion 3,236.
[0015] The container distention 46 may be either a female distention, as shown in Fig. 4
or a male distention 50 as shown in Fig. 5. The lip distention may be either the mae
lip distention 48 as shown in Fig. 4 or a female distention 52 as shown in Fig. 5.
[0016] In preferred embodiments at least one of the container and lip distentions 46,48
or 50,52 includes a positive force threshold deformable rim for a stretchingly but
recoverably deforming during mating engagement to permit engagement of the container
and lip distentions 46,48 or 50,52. As shown in Fig. 4, lid lip distention 48 includes
a rim 49 which has a dimension extending outwardly from lid portion 34 which is greater
than the corresponding portion of container distension 46 to snap the cover in place,
and thereby to form a positive recloseable engagement. An alternative embodiment is
set forth in Fig. 5, wherein the lid lip distention and container lip distentions
are essentially reversed, with the lid lip distention disposed exterior to the container
lip distentions.
[0017] An alterative embodiment is set forth in Fig. 5, wherein the lid lip distention and
container lip distentions are essentially reversed, with the lid lip distention disposed
exterior to the container lip distention. The improved recloseable clamshell container
portion 12 of the present invention may preferably include a laterally extending container
flange 54. Such laterally extending container flange 54 extends preferably laterally
of container lip 32. In such preferred embodiments, the container flange 54 extends
circumferentially of substantially the entirety of the container lip portion 32 as
shown in Fig. 1.
[0018] The lid portion 34 may further preferably include a lid flange 56 which extends laterally
from the lid lip portion 36 thereof for overlapping disposition with the container
flange 54. The container flange 54 and the lid flange 56 are sealed together in preferred
embodiments. A peal opening means 58 as shown in Fig. 1 includes a line of reduced
strength 60 as shown in Fig. 6 wherein indentation may be made, such as by heat sealing
bar upon container flange 54 and lid flange 56, such that a peal force may be directed
along an opening strip for removal of at least a substantial portion of either the
container flange 54, or in more preferred embodiments, the lid flange 56.
[0019] The basic and novel characteristics of the improved methods and apparatus of the
present invention will be readily understood from the foregoing disclosure by those
skilled in the art. It will become readily apparent that various changes and modifications
may be made in the form, construction and arrangement of the improved apparatus of
the present invention, and in the steps of the inventive methods hereof, which various
respective inventions are as set forth hereinabove without departing from the spirit
and scope of such inventions. Accordingly, the preferred and alternative embodiments
of the present invention set forth hereinabove are not intended to limit such spirit
and scope in any way.
1. A recloseable hermetically sealed, modified atmosphere package comprising:
a substantially rigid container portion including bottom with container sidewalls
connected thereto and projecting upwardly therefrom; and
a separately formed substantially rigid lid portion;
said container sidewalls connected together at their respective lateral edges to
form container corners;
said connected sidewalls together forming a container lip portion disposed at the
upper extremity of the connected sidewalls unitarily extending along the top portion
of each sidewall and each container corner;
said lid portion including a centrally dome portion bordered by a lid lip portion
and upwardly extending therefrom, and said lid lip portion substantially congruently
shaped with at least a portion of said container lip portion for mating engagement
therewith to form a hermetically sealed, modified atmosphere package;
substantially congruently-shaped lid locking and matingly engageable respective
container and lid distentions, disposed on each said container lip portion and said
lid lip portion; and
container and lid flanges extending circumferentially around substantially the
entirety of said container lip and said lid lip for overlapping disposition with each
other;
said container flange and said lid flange being sealed together;
said lid flange having peel opening means including a line of reduced strength
disposed upon said lid flange for directing a peel force therealong for removal of
at least a substantial portion of said lid flange for opening said package;
said container portion and said lid portion joined by a hermetic seal to enclose
an hermetically sealed volume therewithin; and
a food product and a substantially inert gas contained within said hermetically
sealed volume to form a modified atmosphere package for containing said food product,
said inert gas surrounding said food product until said peel opening means is used
to open said package.
2. The package of claim 1 wherein said container distention is selected from the group
consisting of male and female distentions.
3. The package of claim 2 wherein said lip distention is selected from the group consisting
of female and male distentions to matingly engage with said container distention.
4. The package of claim 1 wherein said container flange and said lid flange include respective
seal indentations which are bonded together, and which form a line of reduced strength
thereon for directing a peel force therealong.
5. The package of claim 1 wherein said substantially congruently-shaped lid locking and
matingly engageable respective container and lid distentions are disposed respectively
at each of said container corner portions and at each of said lid corner portions.
6. The package of claim 1 wherein said package lid and container are made of a barrier
material against movement of gases to or from said package.