Tamper Evident Container

Abstract

A thermoformed thermoplastic container has a lid which closes on a base in a snap fit. A signal tab is hinged to the base and has a tubular projection which folds over the lid and is received in a friction fit with a downwardly extending lid projection. After the container is filled with product, the signal tab is pressed into place on the lid and lies flat. In order to open the lid the signal tab is pulled up, thereby severing a perforated line extending around the lid projection, and separating the lid projection from the lid which prevents the signal tab from again engaging with the lid, thereby serving as an indicator to a customer that the package has been opened.

Description

CROSS REFERENCES TO RELATED APPLICATIONS

Not applicable.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates to reclosable containers in general, and more particularly to containers having elements which indicate that the container has been opened after its original closure.

There are a number of consumer products, such as bakery or deli foods, which are placed in containers which are closed and put on display for consumer selection. This type of merchandizing can reduce retailer labor, and allows consumers to select the products they desire at their own pace. However, particularly with consumable foodstuffs, customers may seek some assurance that the products they are purchasing have not been tampered with or been pilfered by others. This can be done by applying a shrink-wrapped plastic band to the sealed container, although this requires special equipment and can unduly add cost.

Containers are also known which employ press-fit connectors on the container base and lid which engage with one another when the container is closed to retain the container in a closed configuration. Weakened regions of material such as perforations are disposed such that the force necessary to open the lid causes portions of the container to be severed, either to be separated from the container or to be retained on an opposed container part. Such arrangements provide evidence of tampering either due to the absence of some package part, or due to the open condition of the container. Yet for the untrained observer, the absence of a container part may not immediately indicate tampering, and, although an open container is readily understood, customers may wish to have containers that are reclosable for retention of partial quantities of product.

What is needed is an economical container that effectively presents consumer merchandise, is reclosable, and which clearly indicates that it has been opened after its initial closure.

SUMMARY OF THE INVENTION

The container of the present invention is preferably formed of thermoformed thermoplastic material, and has a lid which closes on a base in a retention fit. A signal tab is hinged to the base and has a tubular projection which folds over the lid and is received in a friction fit with a downwardly extending lid projection. After the container is filled with product, the signal tab is pressed into place on the lid and lies flat. In order to open the lid the signal tab is pulled up, thereby severing a perforated line extending around the lid projection, and separating the lid projection from the lid which prevents the signal tab from again engaging with the lid, thereby serving as an indicator to a customer that the package has been opened. The lid may be hinged to the base, or the lid may be entirely separable from the base and multiple signal tabs may be provided on multiple sides of the container to engage with multiple lid projections. Because the signal tab plays no part in retaining the lid in its closed condition, the package may always be reclosed.

It is an object of the present invention to provide a reclosable container which provides an indication of access to its interior after its original closure.

It is a further object of the present invention to provide a tamper evident mechanism suitable for a wide variety of reclosable containers.

Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of the container of this invention in an open configuration.

FIG. 2 is a fragmentary isometric view of the container of FIG. 1 with the lid closed on the base, prior to engagement of a signal tab.

FIG. 3 is a fragmentary isometric view of the container of FIG. 2 with the signal tab closed on the lid.

FIG. 4 is a fragmentary isometric view of the container of FIG. 3 with the signal tab opened and indicating that the container's closure has been disturbed.

FIG. 5 is a cross-sectional view of the container of FIG. 1 in the process of being closed.

FIG. 6 is a cross-sectional view of the container of FIG. 3 taken along section line 6-6.

FIG. 7 is a cross-sectional view of the container of FIG. 4 taken along section line 7-7.

FIG. 8 is an exploded isometric view of an alternative embodiment container of this invention having a lid which is fully separable from the base.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring more particularly to FIGS. 1-8, wherein like numbers refer to similar parts, a reclosable container 20 is shown in FIGS. 1-7. As shown in FIG. 1, the container 20 is preferably thermoformed from a sheet of thermoplastic material, for example transparent polyethylene terephthalate (PET). The container has a base 22 with a bottom wall 24 and an upwardly extending side wall 26 which define a container interior 28 which will receive contents such as food products. The side wall 26 extends to an upper lip 30 which has a surrounding peripheral skirt 32 which terminates in an outwardly extending terminal flange 34.

An integral hinge 36 extends from the terminal flange 34, and a lid 38 is connected by the hinge so it may be pivoted into a closed position on the base 22. The lid 38 has an outwardly extending flange 40 which is connected to the hinge 36, and a peripheral skirt 42 which extends upwardly from the flange. A top wall 44 extends from the skirt 42, such that when the lid 38 is closed on the base 22 the container interior 28 is sealed. The top wall 44 is preferably formed with an interior skirt 46 which is configured such that the peripheral skirt 42 and the interior skirt snap into engagement with the base peripheral skirt 32 and portions of the base side wall to retain the lid in a closed configuration on the base. The container 20 may thus be loaded with product and then placed on display in a retail establishment for consumer self-service. However, because the lid may be repeatedly opened and resealed on the base, a consumer will desire to know that the contents of the container have not been tampered with after the initial loading with product by the retailer. The consumer is provided with this information by a tamper-evident mechanism 48 which is integrally formed with the container 20.

The tamper-evident mechanism 48 has a signal tab 50 which is connected by an integrally formed hinge 52 to the base terminal flange 34. The signal tab 50 has a narrow rectangular spacer element 54 which is joined by an intermediate integrally formed hinge 56 to a main element 58. The main element 58 is formed with a tubular projection 60 which may be generally cylindrical or tapered like the frustum of a cone.

The tamper-evident mechanism 48 further has a cooperating structure formed on the lid 38 of the container 20. As shown in FIG. 5, the lid 38 has an upper wall 62 which extends inwardly from the peripheral skirt 42. A lid projection 64 extends downwardly from the lid upper wall 62 and is of a size and shape to engage with the signal tab projection 60 in an interference or friction fit. For example, the lid projection 64 may be generally square in section, to engage with the frustoconical signal tab projection.

The base 22 has an upper wall 66 which extends inwardly from the base peripheral skirt 32 and is positioned to directly underlie the lid upper wall 62 when the lid 38 is closed on the base. The base upper wall 66 and the lid upper wall are thus substantially parallel and in close proximity to one another when the lid is closed on the base. A relief 68 is formed in the base upper wall 66 to allow the lid projection to pass through without obstruction. The relief 68 may be a die-cut opening, but for ease of manufacturing it is formed as a downwardly extending closed projection. The relief 68 is larger than the lid projection and does not engage it. Hence when the lid 38 is closed on the base 22, the lid projection does not hamper the snap fit seal between the lid and the base.

As shown in FIG. 2, a region of weakened material 70 is formed in the lid upper wall 62 around the lid projection 64. The region of weakened material 70 may be formed, for example, by a die-cut with notched segments or perforations, or by a thinning of the plastic or by other means. As shown in FIG. 6, the region of weakened material 70 may define, for example, a circle, which is greater in diameter than the size of the base upper wall relief 68, such that the region of weakened material is supported on the base upper wall 66 and separation of the lid projection 64 at the region of weakened material is prevented when the lid projection 64 is pressed downwardly. It will be noted that the closed cavity of the base relief 68 serves to protect the downwardly extending lid projection from inadvertent engagement by a customer which might tend to push the projection 64 upwardly and disturb the region of weakened material 70.

Two detents 72 are formed, one on either side of the signal tab projection 60. These detents prevent the main element 58 of the signal tab 50 from approaching so close to the base upper wall 66 so as to prevent a user from engaging the main element 58 and pulling it upwardly. The height of the detents 72 serves to maintain a narrow gap between the base upper wall 66 and the signal tab main element, so an edge of the main element can be readily engaged and manipulated.

The container 20 is loaded with product while the lid 38 is opened, as shown in FIG. 1. The lid 38 is then closed on the base 22 as shown in FIGS. 2 and 5. The lid 38 has molded structure which engages the base 22 and secures the lid in a closed configuration on the base. For example, the lid outer peripheral skirt 42 and interior skirt 46 engage the base peripheral skirt 32 and side wall 26 respectively. Once closed on the base, the lid 38 may be opened and closed repeatedly. To provide a customer an indication of whether the container has been opened after its initial loading, the signal tab 50 is pivoted on the hinges 52, 56, to bring the signal tab projection 60 into engagement with the lid projection 64, as shown in FIGS. 3 and 6. The signal tab spacer element 54 is at least as wide as the distance the base upper wall 66 is spaced above the base terminal flange 34. The signal tab projection 60 is dimensioned so that when it is pressed into engagement with the lid projection 64 the parts are deformed to retain the two in engagement with one another. As shown in FIG. 3, the lid upper wall 62 is preferably slightly relieved below the level of the surround lid top wall 44, such that the engaged signal tab 50 does not project substantially above the top wall and provide an obstruction which might be readily engaged when handling loaded containers, for example while stacking them one on another.

Once the signal tab projection 60 is secured to the lid projection 64, the lid 38 may not be opened without first getting the signal tab 50 out of the way. However, the dimensions of the parts are such that the force required to separate the signal tab projection 60 from the lid projection 64 is greater than the force required to sever the line of weakened material 70 and separate the lid projection 64 and its surrounding portion of the lid upper wall 62 from the lid. Thus, as shown in FIGS. 4 and 7, when the signal tab 50 is engaged by a user and pivoted away from the lid, the discrete element 73 containing the lid projection 64 remains affixed to the signal tab, leaving a perforated opening 75 in the lid above the base relief 68. The signal tab 50, no longer connected to the lid, then extends away from the base 22 providing a clear signal that the container has been tampered with after its initial closure. The hinge 52 may undergo plastic deformation when the signal tab is folded into engagement with the lid, with the result that the signal tab extends vertically when released from the lid, as shown in FIG. 7. Although the container 20 may still be closed, the signal tab 50 can not be restored to its engagement with the lid 38. It should be noted that the perforated opening 75 does not communicate with the container interior 28, and hence does not compromise the seal of the container.

It should be noted that although the projection on the signal tab has been illustrated as extending from the signal tab towards the lid to engage with a downwardly extending projection on the lid, it and the lid projection could also be projecting upwardly.

It should be noted that, although in the FIGS. 1-7, the container is shown having a clamshell construction with a lid which is attached by an integral hinge to the base, the container may have an unhinged lid. An alternative embodiment container 74, shown in FIG. 8, employs a lid 76 which is not hinged to the container base 78 but is entirely separable from the base. In such a configuration, the container 74 has multiple tamper-evident mechanisms 48, at least one on multiple sides of the container, for example on two opposite sides of the lid, whereby at least one of the tamper-evident mechanisms must be disturbed to gain access to the container interior. The mechanisms 48 may be similar to the ones discussed above.

It should be noted that the container lid may have a perforation along the hinge or parallel to the hinge to permit it to be separated from the base by the consumer.

It should be noted that although a particular friction fit arrangement is disclosed between the signal tab projection and the lid projection, other structures which allow the engagement between the two parts may be employed, so long as the arrangement is such that the force required to separate the two parts is greater than the force required to sever the region of weakened material.

It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.

Claims

1. A container comprising:

a base having portions defining an interior and having an upper wall;

a lid having an upper wall, the lid being releasably engageable with the base so the lid upper wall overlies the base upper wall;

portions of the lid upper wall which define a lid projection, wherein a region of weakened material extends around the lid projection;

a signal tab connected by a first hinge to the base; and

a projection extending from the signal tab, wherein the signal tab is pivotable about the hinge to engage and connect the signal tab projection with the lid projection, such that when, after said engagement, the signal tab is pivoted away from the container lid, the lid projection which is connected to the signal tab projection is caused to be severed from the lid upper wall at the region of weakened material, thereafter preventing the lid projection from being secured to the lid upper wall and providing an indication of the prior manipulation of the signal tab.

2. The container of claim 1 further comprising portions of the base upper wall which define a relief below the base upper wall, and wherein the lid projection extends into the relief when the lid is closed on the base.

3. The container of claim 2 wherein the relief comprises a closed cavity which extends beneath the base upper wall.

4. The container of claim 1 wherein the lid has a top wall with a downwardly extending peripheral skirt spaced from a downwardly extending interior skirt, and where the base has a downwardly extending peripheral skirt spaced outwardly from a base side wall, and wherein the lid peripheral skirt and interior skirt engage the base peripheral skirt and side wall to retain the lid on the base when it is closed thereon.

5. The container of claim 1 wherein the signal tab comprises:

a first element which extends outwardly from the first hinge to a second hinge; and

a second element which extends outwardly from the second hinge, the hinge tab projection extending from the second element.

6. The container of claim 1 wherein the base upper wall extends to underlie the region of weakened material, such that downward force on the lid projection is resisted by the base upper wall and severing of the region of weakened material is resisted.

7. The container of claim 1 wherein the lid is connected to the base by a hinge, and is pivotable about the hinge from a position which reveals the container interior to a position which closes the container interior.

8. The container of claim 1 wherein the lid is separable from the base, and further comprising:

portions of the lid which define a second lid projection surrounded by a second region of weakened material, positioned opposite the lid projection;

a second signal tab connected by a second hinge to the base; and

a second projection extending from the second signal tab, wherein the second signal tab is pivotable about the second hinge to engage and connect the second signal tab projection with the second lid projection, such that when, after said engagement, the second signal tab is pivoted away from the container lid, the second lid projection which is connected to the second signal tab second projection is caused to be severed from the lid upper wall at the second region of weakened material, thereafter preventing the second lid projection from being secured to the lid and providing an indication of the prior manipulation of the second signal tab.

9. The container of claim 1 wherein the lid has a top wall which projects above the level of the lid upper wall, such that when the signal tab is engaged with the lid projection, the signal tab does not project substantially above the level of the lid top wall.

10. The container of claim 1 wherein the region of weakened material comprises a line of perforations which encircles the lid projection.

11. A container comprising:

a container first part having a first wall;

a container second part having portions defining a second wall, the second part being releasably engageable with the first part so the first wall and the second wall are substantially parallel and in close proximity, the engaged container first part and container second part defining a container interior;

portions of the first wall which define a first projection, wherein a region of weakened material extends around the first projection;

a signal tab connected by a hinge to the container second part; and

a second projection extending from the signal tab, wherein the signal tab is pivotable about the hinge and the second projection is configured to cooperate with the first projection to secure the signal tab second projection to the container first part first projection, such that after said engagement, pivoting of the signal tab away from the container first part causes the first projection to be severed from the first part first wall at the region of weakened material thereafter preventing the signal tab second projection from being secured to the container first part first wall and providing an indication of the prior manipulation of the signal tab.

12. The container of claim 11 further comprising portions of the first container part which engage with portions of the second container part to engage them together and retain the container in a closed configuration.

13. The container of claim 11 wherein the signal tab comprises:

a first element which extends outwardly from the hinge to a second hinge; and

a second element which extends outwardly from the second hinge, the hinge tab second projection extending from the second element.

14. The container of claim 11 wherein the container first part is entirely separable from the container second part, and wherein portions of the container first part and container second part define a second tamper evident mechanism positioned opposite the signal tab.

15. The container of claim 11 wherein the signal tab second projection and the container first part first projection are configured to engage with each other in a friction fit.

16. A container comprising:

a base having an upper wall, and a side wall which extends downwardly from the upper wall to a bottom wall, the base defining a container interior;

a lid having an upper wall, the lid being releasably engageable with the base so the lid upper wall overlies the base upper wall, and so the lid closes the container interior;

portions of the base which define a relief below the base upper wall;

portions of the lid upper wall which define a downwardly extending lid projection, the lid projection extending into the base relief when the lid is closed on and engaged with the base, wherein a region of weakened material extends around the lid projection;

a signal tab hingedly connected to the base; and

a projection extending from the signal tab to be received within the lid projection and engaged thereto, such that when the signal tab is pivoted away from the container lid, the lid projection is severed from the lid upper wall at the region of weakened material thereafter preventing the lid projection from being secured to the lid upper wall and providing an indication of the prior manipulation of the signal tab.

17. The container of claim 16 wherein the relief comprises portions of the base which define a downwardly extending closed projection.

18. The container of claim 16 wherein the signal tab is connected to the base by a first hinge, and further comprises:

a first element which extends outwardly from the first hinge to a second hinge; and

a second element which extends outwardly from the second hinge, the hinge tab projection extending from the second element.

19. The container of claim 16 further comprising portions of the lid which engage the base to retain the container in a closed configuration.

20. The container of claim 17 wherein the lid is entirely separable from the base, and wherein portions of the lid and base define a second tamper evident mechanism positioned opposite the signal tab.