U.S. patent application number 12/356461 was filed with the patent office on 2010-07-22 for food container having improved tamper evident features.
This patent application is currently assigned to Anchor Packaging, Inc.. Invention is credited to Kevin Krueger, Michael Pohlman, Michael Thaler.
Application Number | 20100181323 12/356461 |
Document ID | / |
Family ID | 42336123 |
Filed Date | 2010-07-22 |
United States Patent
Application |
20100181323 |
Kind Code |
A1 |
Thaler; Michael ; et
al. |
July 22, 2010 |
FOOD CONTAINER HAVING IMPROVED TAMPER EVIDENT FEATURES
Abstract
A plastic food container includes a lid adapted for sealing
arrangement with a base. The rim of the base has an undercut
formation adapted to receive the perimeter flange and flange tab of
the lid when the lid and base are in the sealed arrangement. The
flange tab includes an undercut release mechanism that allows a
user to grasp a portion of the flange tab and initially open a
sealed container via the extraction of the flange tab from the
undercut formation by application of pulling force to the undercut
release mechanism. The flange tab includes tamper evident means
that provides visible indication that the undercut release
mechanism has been utilized to initially open the sealed
container.
Inventors: |
Thaler; Michael; (Roswell,
GA) ; Krueger; Kevin; (Fenton, MO) ; Pohlman;
Michael; (Ballwin, MO) |
Correspondence
Address: |
GALLOP, JOHNSON & NEUMAN, L.C.
101 S. HANLEY, SUITE 1600
ST. LOUIS
MO
63105
US
|
Assignee: |
Anchor Packaging, Inc.
Ballwin
MO
|
Family ID: |
42336123 |
Appl. No.: |
12/356461 |
Filed: |
January 20, 2009 |
Current U.S.
Class: |
220/574 ;
220/266; 220/810 |
Current CPC
Class: |
B65D 2543/00296
20130101; B65D 2543/00796 20130101; B65D 2543/00768 20130101; B65D
2543/00101 20130101; B65D 2543/00388 20130101; B65D 2543/00685
20130101; B65D 2543/00509 20130101; B65D 2543/00351 20130101; B65D
43/0254 20130101; B65D 2543/00842 20130101; B65D 2543/0062
20130101 |
Class at
Publication: |
220/574 ;
220/266; 220/810 |
International
Class: |
A47G 19/00 20060101
A47G019/00; B65D 41/32 20060101 B65D041/32; B65D 51/04 20060101
B65D051/04 |
Claims
1. A plastic food container comprising: a lid adapted for sealing
arrangement with a base; the lid having a perimeter flange; a
flange tab integrally formed in the perimeter flange; the base
having a floor and a rim and a sidewall extending between the floor
and the rim; the rim of the base having an undercut formation, the
undercut formation being adapted to receive the perimeter flange
and flange tab when the lid and base are in the sealed arrangement;
the flange tab including an undercut release mechanism: the
undercut release mechanism being adapted to permit a user to: a)
grasp a portion of the flange tab; and b) initially open a sealed
container via the extraction of the flange tab from the undercut
formation by application of pulling force to the grasped portion of
the flange tab; and the flange tab further including tamper evident
means that provides visible indication that the undercut release
mechanism has been utilized to initially open the sealed
container.
2. The food container of claim 1 wherein the undercut release
mechanism is integrally formed in the flange tab.
3. The food container of claim 1 wherein the tamper evident means
includes a fracture line on the flange tab that ruptures upon
utilization of the undercut release mechanism.
4. The food container of claim 3 wherein the fracture line is
located, extended or patterned on the flange tab to enhance the
deformation of the flange tab when the undercut release mechanism
is utilized.
5. The food container of claim 2 wherein the undercut release
mechanism is a grip tab defined by a frangible outline in the
flange tab.
6. The food container of claim 5 wherein the grip tab can be
extracted from the flange tab and placed in a graspable position
via the application of finger pressure within the frangible
outline.
7. The food container of claim 5 wherein the grip tab includes a
pressing area formed in the grip tab and a pop-up tip, the
application of downward pressure on the pressing area causing the
pop-up tip to separate from the flange tab and assume a graspable
position.
8. The food container of claim 1 wherein the lid is hinged to the
base.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
SEQUENCE LISTING, TABLE OR COMPUTER PROGRAM ON COMPACT DISC
[0003] Not applicable.
FIELD OF INVENTION
[0004] This invention relates generally to plastic food containers.
The invention is more specifically related to resealable plastic
food containers having tamper evident sealing mechanisms.
BACKGROUND OF THE INVENTION
[0005] It is known to use plastic containers in the food
preparation and restaurant industry to package prepared foods. The
typical food container of the prior art consists of a solid color
(typically black) base and a clear lid. The clear lid of the prior
art plastic food container allows visible inspection of the
container contents. The lid and base of the prior art plastic food
container may be separate articles or may be hingedly attached to
each other.
[0006] In order to maintain the quality of food contents and
prevent tampering with the contents of a sealed container, it is
desirable that the food container, once sealed, not be capable of
being initially opened without visible indication of the container
having been opened. Accordingly, it is known in the prior art to
manufacture food containers having tamper evident sealing
mechanisms. In this regard, the prior art plastic food container
has utilized a band of tape around the sealed container or a
sticker label extending across a portion of the contact area of lid
and base rims of the sealed container for tamper evidence. Opening
the container (i.e., separating the lid from the base) requires
rupturing the band or sticker label. The ruptured band or label
provides evidence of tampering or initial opening of the sealed
container. A problem with this method of tamper evidence is that
the container requires articles apart from the container itself to
effect the tamper evidence. In addition, to make the container
tamper evident, the additional step of applying the band or label
is required after sealing the container.
[0007] To address the above problem, container manufacturers have
designed containers having integral tamper evident features.
Typically, these containers consist of a lid that is hingedly
attached to a base. The lid seals to the base by superposing the
rim of the lid upon the rim of the base. The lid and base each have
interlocking elements respectively located on or near the lid rim
and base rim. The interlocking element of the lid or base is
conventionally located on a tab or flange extending from the rim of
the lid or base. Either or both of the tabs are attached to their
respective rims by a frangible section of plastic. When the lid and
base are placed in sealing arrangement, the interlocking elements
on or near the lid rim and base rim engage and lock together. In
order to open the sealed container, the frangible section of one or
both tabs must be ruptured so as to release the tab or tabs from
the container. Because the interlocking sealing elements are
located on the tabs, rupturing one or more tabs from the container,
disables the locking mechanism. The ruptured tab provides evidence
of the container having been opened.
[0008] One shortcoming with the prior art food container relying on
interlocking elements located upon a outer frangible tab is that
the interlocked tabs can be cut from the container in clean fashion
using scissors or another cutting implement so as to remove any
indicia of the container having had a tamper evident mechanism.
Another shortcoming involves the additional plastic required to
manufacture the tabs. Still another problem with the prior art
tamper evident food container arises from the sealing arrangement
of the container rims. As noted, in the prior art container one rim
(typically the lid rim) superposes over the other rim (typically
the base rim) such that at least one of the rim edges is exposed.
With this type of sealing arrangement and construct in plastic
containers, the lid and base can be partially pried open by
inserting a thin object underneath an exposed rim edge at a point
on the container distal from the tamper indicator. By partially
prying open the rims in this fashion, one can doctor or tamper with
the contents of the apparently sealed container without activating
the tamper indicator.
[0009] There is thus a need in the art for a reclosable plastic
food container that is easy for end consumers to operate; combines
reliable tamper evidence and defense against prying intrusion; and
that uses a minimum of material to manufacture.
SUMMARY OF THE INVENTION
[0010] The present invention satisfies the needs in the art and
provides an aesthetically appealing food container that is easy to
use and that is both tamper resistant and tamper evident. In this
respect the present invention food container comprises a plastic
food container having a lid adapted for sealing arrangement with a
base. The lid has a perimeter flange that includes at least one
localized, integrally formed flange tab. The base has a floor and a
rim and a sidewall extending between the floor and the rim. The rim
of the base has an undercut formation. The undercut formation is
adapted to receive the perimeter flange and flange tab when the lid
and base are in the sealed arrangement. The flange tab includes an
undercut release mechanism, which allows a portion of the flange
tab to be grasped and pulled. Pulling the flange tab extracts its
edge from the undercut formation of the base rim. The undercut
release mechanism is formed such that the pulling force necessary
to extract the flange tab from the undercut formation deforms the
flange tab. The deformed flange tab provides visible evidence that
the sealed container has been initially opened.
[0011] More specifically, the container comprises a lid adapted for
sealing arrangement with a base. The lid comprises an upper
portion, a descending surface and a rim that engages the rim of the
base. In a preferred embodiment and as viewed from a cross section
aspect, the upper portion of the lid comprises one or more
horizontal and vertical surfaces that extend to form the descending
surface. The descending surface extends to form a horizontal
transition segment. This segment descends to form a multi-segment
rim structure. This rim structure includes a generally vertically
oriented inner wall. The inner wall curves outwardly (peripherally)
to form a peripherally projecting segment that defines the
lowermost point of the lid.
[0012] The respective rims of the lid and base each have a
complementary engaging multi-surface (segment) structure. In this
regard, the lid rim structure includes a vertical sealing segment
that extends upwardly from the peripherally projecting segment to a
perimeter flange. The lid vertical sealing segment is angled
inwardly (towards the interior of container).
[0013] In addition to having a complementary rim with multi-segment
structure, the base comprises a floor and a sidewall, the sidewall
extending between the floor and the rim. The base rim structure
contains an undercut formation that is adapted to engage the
perimeter flange of the lid. The method by which the lid is
retained by the undercut formation of the base rim provides defense
against access to the sealed container contents via prying of the
lid from the base.
[0014] The perimeter flange of the lid includes at least one
integrally formed flange tab, which when the container is sealed is
also protectively captured by the undercut structure of the base
rim. This flange tab is generally planar and incorporates an
undercut release mechanism that allows a user to extract the
engaged flange tab from the base rim. In the preferred embodiment,
the undercut release mechanism is a releasable grip tab integrally
formed in the flange tab via a frangible outline of perforations or
scoring. The perforations or scoring define the shape of the grip
tab. By providing the container with these features, a three-step
process is required to open the container. First, a separation
force must be applied to the grip tab to cause rupture of its
frangible outline and the grip tab to pop up out of the flange tab
to a position it can be grasped by a thumb and forefinger. Second,
the now released grip tab is pulled toward the user, causing the
engaged flange tab to roll inwardly down and be released by the
base rim structure. Third, once the flange tab is disengaged from
the base rim structure, the lid can be removed from the base by
pulling the flange tab up and inwardly toward the center of the
container. This last pulling action causes the disengagement of the
lid perimeter flange from the base rim.
[0015] The undercut release mechanism is further adapted to deform
when tab-releasing forces are applied to it. This deformation
provides visible indication that the container has been initially
opened. In this regard, the flange tab includes a fracture line
that prefereably emanates from the frangible outline defining the
grip tab. This fracture line is designed to rupture when pulling
action is imparted to the grip tab to extract the flange tab from
the base rim's undercut formation. The rupturing of this fracture
line provides visible indication that the grip tab has been
employed to open the container. In addition, the undercut release
mechanism is designed such that once the fracture line ruptures,
the application of pulling force to the grip tab or flange tab will
cause further visible deformation of the flange tab from its
original planar shape. This deformation provides additional indicia
that the lid retaining mechanism of the container has been
compromised and that the lid has been subjected to opening
forces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a preferred embodiment of
the present invention container in the sealed arrangement.
[0017] FIG. 2 is a side elevation view of the preferred embodiment
present invention container in the sealed arrangement.
[0018] FIG. 3 is a perspective view of the base of the preferred
embodiment present invention container.
[0019] FIG. 4 is a cross-section view taken along line A-A of FIG.
1.
[0020] FIG. 5 is a cross-section view taken along line B-B of FIG.
3.
[0021] FIG. 6 is more detailed view of circumscribed area Z of FIG.
5 showing the multi-segment rim structure of the base of the
preferred embodiment present invention container.
[0022] FIG. 7 is a plan view of the lid of the present invention
container having a preferred embodiment tamper evident flange
tab.
[0023] FIG. 8 is a cross section view of the rim structure of the
lid of the preferred embodiment present invention container taken
along line C-C of FIG. 7.
[0024] FIG. 9 is a detailed view of circumscribed area Y of FIG. 4
showing the mechanics of engagement between the lid rim structure
and base rim structure when the container is sealed.
[0025] FIG. 10 is a cross section view taken along line D-D of FIG.
7 and showing the profile of a preferred embodiment lid tab.
[0026] FIG. 11 is a cross section view taken along line E-E of FIG.
1 and showing the mechanics of engagement between the flange tab
and the base rim structure when the container is sealed.
[0027] FIG. 12 is a perspective view of the tamper evident flange
tab showing the grip tab deployed and ready to be pulled to open
the container.
[0028] FIG. 13 is a perspective view of the tamper evident flange
tab showing example deformation of the flange tab after the
container has been opened through use of the grip tab.
[0029] FIGS. 14a-d are plan views of alternate embodiment flange
tabs having differently configured fracture lines designed to
enhance tamper evidence.
[0030] FIG. 15 is an exploded perspective view of a lid flange tab
and base platform having a simpler grip tab construct designed to
be deployed via the application of upwardly directed finger
pressure through a hole in the platform.
DETAILED DESCRIPTION
[0031] A preferred embodiment container 10 of the present invention
in the sealed arrangement is shown in FIGS. 1 and 4. As shown by
these figures container 10 is composed of lid 11 and base 25. Lid
11 includes upper portion 12, descending surface 13 and
multi-segment rim 14. Lid 11 is manufactured from a conventional
plastic material and is clear. Upper portion 12 is preferably flat,
but can be contoured and ribbed in accordance with the prior art to
enhance such factors as container volume, strength, nesting of
multiple lids, stackability of sealed containers and see-through
visibility. In the preferred embodiment lid upper portion 12
includes top plateau 15 and intermediate terrace 16. First lid
transition segment 17 extends between plateau 15 and terrace 16.
Terrace 16 continues on to form second vertical transition segment
18. Vertical transitional section 18 provides structural rigidity
to lid 11 and extends from terrace 16 to descending surface 13,
which in the preferred embodiment is an arcuate segment with its
concave surface directed toward the interior of container 11. Third
(horizontal) lid transition segment 23 extends between descending
surface 13 and inner wall 19 of lid rim structure 14 and provides
structural rigidity to lid 11. Lid 11 is shaped so as not to allow
a finger-hold on the lid once the lid is in sealing arrangement
with the base.
[0032] The structure of lid rim 14 will now be discussed in further
detail. As best shown in FIGS. 4, 7, 8 and 9, lid rim 14 includes
peripherally projecting segment 20, which extends between inner
wall 19 and lid vertical sealing segment 21. The cross-section
profile of segment 20 is generally horizontal. The profile,
however, can be shaped to include structure such as ribbing, curves
or bends to modulate rim rigidity or flexibility so as to enhance
the closing, sealing and opening functions of the rim as needed.
The drawings depict a preferred embodiment cross-section profile of
this peripherally projecting segment. Lid vertical sealing segment
21 extends upwardly between peripherally projecting segment 20 and
peripheral flange 22. Lid vertical sealing segment 21 is preferably
angled inwardly (towards the interior of container 10).
[0033] The structure of base 25 and its rim structure 30 is best
shown in FIGS. 3, 5, 6 and 9. Base 25 includes floor 31 adjoined to
sidewall 32. Sidewall 32 extends between base floor 31 and
multi-segment rim 30. The structure of base rim 30 is adapted to
complementarily engage the structure of lid rim 14 when lid 11 and
base 25 are placed in sealing arrangement. In this respect, the
lower portion of base rim 30 includes sidewall-to-rim transition
segment 33. Transition segment 33 flares outwardly from the top of
sidewall 32 and curves upwardly into base vertical sealing segment
34. Base vertical sealing segment 34 extends upwardly between
sidewall-to-rim transition segment 33 and sealing platform 35. Base
vertical sealing segment 34 is angled inwardly (towards the
interior of container 10) to complementarily engage lid vertical
sealing segment 21 when the container is sealed. Vertical sealing
segment 34 and sealing platform 35 make up the sealing portion of
base rim 30.
[0034] Base rim 30 also includes a tamper-resistant (anti-prying)
portion located above the sealing portion. In this regard rim
structure 30 further includes intermediate vertical segment 36
extending between sealing platform 35 and inwardly angled overhang
segment 37. Overhang segment 37 continues on to form top vertical
segment 38. Top vertical segment 38 extends upwardly, but at an
outward angle to form lead-in chamfer 39. Lead-in chamfer 39
extends between top vertical segment 38 and base rim top 40. Base
rim top 40 extends horizontally outwardly and then descends to form
outer rim wall 41. Outer rim wall 41 extends downwardly until it
meets base flange 42, which extends horizontally outward from base
25.
[0035] FIG. 9 depicts a more detailed view of circumscribed area Y
of FIG. 4 showing the mechanics of engagement between the
structures of lid rim 14 and base rim 30 when the container is
sealed. Container 10 is sealed by placing lid 11 over base 25 and
pressing lid 11 downward on base 25 so that the respective rims
assume the arrangement in FIG. 9. In this regard, lid 11 is
"snapped" into place and retained by and inside base 25. When
sealed, vertical sealing segment 21 and flange 22 of lid 11
respectively contact base vertical sealing segment 34 and sealing
platform 35 of base 25. These contacting rim surfaces impede the
spillage of solid, liquids and vapors out of the sealed
container.
[0036] In addition to providing protection against spillage, the
sealing arrangement between the rims of the present invention
container also protects against intrusion into the container by way
of prying. As shown in FIGS. 6 and 9, sealing platform 35,
intermediate vertical segment 36, overhang segment 37 and top
vertical segment 38 form an undercut in rim structure 30. When
container 10 is sealed, flange 22 drops into, and the entire lid is
securely retained by, this undercut formation. Moreover, once
container 10 is sealed in this fashion, the edge 24 of lid flange
22 is protected from prying instruments by the undercut formation
of rim 30. Furthermore, because there is no corresponding lid
structure adjacent to base flange 42, base flange 42 does not serve
as a prying access point. This lack of an easily accessible pry
point is in contrast to prior art containers having superposed rims
with exposed rim edges.
[0037] Lid 11 further includes flange tab 60 having a
tamper-evident mechanism. Flange tab 60 constitutes a localized
planar extension of peripheral flange 22 that is retained by the
undercut formation of rim structure 30. The accompanying figures
show a preferred embodiment container having only one flange tab,
but the container could be formed with a plurality of flange tabs.
FIGS. 10-12 show the structure of a preferred embodiment tab 60
having tamper evident features. As shown in these figures, flange
tab 60 extends outwardly from flange 22 at one corner or perimeter
segment of lid 11. Flange tab 60 includes integrally formed grip
tab 61, which is defined by frangible outline 62. Frangible outline
60 can be formed by way of perforations, scoring or thinning of the
lid material. In the shown preferred embodiment, frangible outline
62 is formed by way of perforations. Frangible outline 62 is
preferably U-shaped. Grip tab 61 includes pop-up tip portion 65 and
pressing area 63. Pop-up tip 65 is located on flange tab 60 at a
point distal from flange edge 24. As shown in FIG. 7, 10 an 11,
pressing area 63 includes knurlments 64 to demark a visual and
tactile press-down point. Flange tab 60 may include structural
ribbing 71 to rigidify the tab. Grip tab 61 may similarly include
such strengthening ribbing 72.
[0038] Base 25 includes localized platform extension 80 extending
out from sealing platform 35. Platform 80 is positioned, shaped and
adapted to complementarily receive flange tab 60 so that edge 24 is
protectively received by the undercut formation of rim structure
30. Platform extension 80 connects to the structures of rim 30 in
the same fashion as sealing platform 35. In this respect, platform
extension 80 connects to intermediate vertical segment 36, which in
turn connects to inwardly angled overhang segment 37. As shown in
FIG. 11, when the container is in the sealed arrangement, flange
tab 60 is engaged by the undercut structure of base rim 30 in the
same manner as peripheral flange 22 is engaged by the structure of
base rim 30. When flange tab 60 is engaged in this manner, flange
edge 24 is protectively housed within the undercut formation of rim
30. Platform 80 may include structural ribbing 73, which in the
preferred embodiment is horseshoe shaped.
[0039] Flange tab 60 includes an undercut release mechanism that
provides tamper evidence. In the preferred embodiment, this
undercut release mechanism comprises a grip tab 61 integrally
formed in flange tab 60 by means of frangible outline 62. Frangible
outline 62 is adapted to rupture when finger pressure is applied to
one or more pressing areas 63 of grip tab 61 such that grip tab 61
is caused to move in a perpendicular direction relative to the
surface of flange tab 60. In the preferred embodiment, pressing
areas 63 of grip tab 61 are raised and platform extension 80
includes cavity 81. Inclusion of these features enhances the
vertical flexing and movement of grip tab 61 relative to the
horizontal surface of flange tab 60 when pressure is applied to
grip tab 61. Specifically, by raising pressing areas 63 above the
surface of flange tab 60 as indicated in the figures, pressing area
63 is provided with space for downward travel. Similarly, including
cavity 81 in platform 80 enhances the degree of downward travel of
pressing areas 63. In the sealed arrangement, flange tab 60 is in
superpositional contact with platform extension 80.
[0040] The undercut release mechanism is deployed as follows.
Pressing vertically downward upon pressing areas 63 causes the
inner portion of grip tab 61 to descend past the surface of flange
tab 60 and on into cavity 81. When pressing area 63 is caused to
move downward, frangible outline 62 initially ruptures near the
pressing area. This initial rupturing allows grip tab 61 to descend
further relative to flange tab 60. With continued downward pressure
on pressing area 63, pop-up tip 65 of grip tab 61 is pulled away
from flange tab 60 until it completely separates from flange tab 60
along frangible outline 62. Ordinarily, once frangible outline 62
completely ruptures, the downward force exerted upon the pressing
area causes pop-up tip 65 to rise above the flange tab surface to a
point where it can be pinch-gripped by the user's thumb and index
finger. In order to enhance the pop-up action of pop-up tip 65,
grip tab 61 includes scored line 67, which serves as a flex point
when downward pressure is applied to pressing area 63. Further,
cavity 81 is preferably sized and positioned on platform 80 such
that scored line 67 will be situated above distal edge 75 of cavity
80 when the container is sealed. Distal edge 75 thus acts as a
fulcrum against grip tab 61 when grip tab 61 is depressed. By
virtue of distal edge 75 and score line 67, when downward pressure
is applied to pressing area 63 of grip tab 61, grip tab 61 will
bend focally along score line 67, enhancing the pop-up action of
pop-up tip 65. Should the application of pressing force upon grip
tab 61 cause it to descend below flange tab 60 or not result in
pop-up tip 65 of grip tab 61 reaching a point of graspability, then
grip tab 61 can be pulled out from flange tab 60 and into a
graspable position by applying pull-back force against knurlments
64.
[0041] As shown in FIG. 12 once grip tab 61 is in a graspable
position it is deployed and can be used to extract flange tab 60
from rim 30. In this respect, deployed grip tab 61 is grasped and
pulled toward the user. Pulling on grip tab 61 in this fashion
causes flange tab 60 to lift and the edge 24 of flange tab 60 to
point downward and move inward along platform 80 (away from the
undercut formation of base rim structure 30) and towards the center
of container 10. Once edge 24 of flange tab 60 is moved inwardly
past top vertical segment 38 of the undercut formation of base rim
30, flange tab 60 can be pulled out from, and is released by, the
undercut formation of base rim 30. Once flange tab 60 is released
by base rim 30, the user can pull or push the flange tab 60 away
from base 25 causing adjoining sections of peripheral flange 22 to
be pulled out from the undercut formation of rim 30. Once
approximately half of the lid's flange has been pulled out from the
undercut structure of the base rim, lid 11 will openly separate
from base 25.
[0042] The undercut release mechanism of the present invention
container is adapted to distinguish between user actions that
merely cause the initial partial separation of grip tab 61 from
flange tab 60 and actions that indicate opening of the container.
As shown in FIG. 7, flange tab 60 includes one or more further
fracture lines 69 preferably emanating from frangible outline 62
and leading toward edge 24. Fracture line 69 can be formed via
perforations, scoring or thinning of container material. Fracture
line 69 is formed on flange tab 60 such that the force required to
pull edge 24 of flange tab 60 out from the undercut formation of
rim structure 30 also causes flange tab 60 to further visibly
rupture along score line 69. The rupturing of fracture line 69
provides evidence that the undercut release mechanism has been
utilized and the container has been opened. Additionally, once
score line 69 ruptures, the subsequent application of pull force to
grip tab 61 or flange tab 60 will cause flange tab 60 to twist and
deform from its initial planar shape. An example of this
deformation is shown in FIG. 13. Such resulting deformation
provides additional evidence to the user that the container has
actually been opened. By locating, extending or patterning fracture
line 69 the resulting deformation to grip tab 61 or flange tab 60
can be made more prominent. For example, fracture line 69 can be
shaped in accordance with FIGS. 14a-14d in furtherance of enhancing
tamper evidence. As shown in these figures, fracture line 69 can
curve away from frangible outline 62 or can be made as an extension
of frangible outline 62.
[0043] The figures show only a preferred embodiment undercut
release mechanism, the function of which is to effect the
extraction of flange edge 24 from undercut structure of rim 30
while at the same time undergoing visible physical change. Grip tab
61 can be formed in flange tab 60 in a variety of ways such that it
can be deployed and grasped. For example, FIG. 15 depicts a simpler
grip tab 61 construct designed to be deployed via the application
of upwardly directed finger pressure through hole 83 in platform
80. Additionally, the undercut release mechanism could be a
separate element mechanically attached to, as opposed to integrally
formed in, flange tab 60.
[0044] A container constructed in accordance with the present
invention can be manufactured in a variety of shapes and sizes, and
is preferably formed of resins or plastic materials including, but
not limited to, polyethylene, polypropylene, polyvinyl chloride or
polyethylene terephthalate ("PET"). The container lid and base can
be transparent or translucent, and may be colored in either
instance. The container can be provided with vents to promote the
flow of air or steam in or out of the container. Further, the
container can be of any shape, including round or polygonal. The
rim structures of the container may be adapted to include a hinge
such that the lid and base are connected to each other in a
clamshell configuration.
[0045] Having described the invention in detail, those skilled in
the art will appreciate that modifications may be made of the
invention without departing from its spirit. Therefore, it is not
intended that the scope of the invention be limited to the specific
embodiment illustrated and described.
* * * * *