Tamper-evident plastic food container

Abstract

A tamper-evident plastic food container includes a body having a body rim abutting a body hinge panel and a lid having a lid rim abutting a lid hinge panel. And the hinges are connected with the panels. A fragility line extends from an edge of the cover hinge panel to a first point on the panel and then outwardly to the hinge. A line of frangibility strides the hinge and extends inwardly to a second point on the body hinge panel. The line of frangibility extends from the second point to an edge of the body hinge panel. When the container is initially sealed, the fragile lines are separated while applying an upwardly directed force to the first portion of the lid hinge panel and while holding or moving the second portion of the lid hinge panel in a fixed position. Separation of the line of fragility results in two grip portions that can be used to pull the lid away from the body.

Description

[0001] This application is a divisional application of an invention patent application entering the Chinese national phase with an application date of May 19, 2021, application number 202180036408.2, international application number PCT / US2021 / 033194, and name “Tamper-evident Plastic Food Container”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] not applicable.

[0004] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0005] not applicable.

[0006] Sequence listing, table or computer program on CD-ROM

[0007] not applicable. Technical Field

[0008] The present invention relates generally to plastic food containers. More particularly, the present invention relates to a reclosable plastic food container having a tamper-evident sealing mechanism. Background Art

[0009] The use of plastic containers for packaging prepared food in the food preparation and catering industries is known. Typical food containers of the prior art consist of a transparent or solid color body and a transparent cover. In order to maintain the quality of the food contents and prevent casual access to the contents of a sealed container, it is desirable that the food container, once initially sealed, cannot be initially opened without a visible indication that the container has been opened. In order to achieve this feature, container manufacturers have designed plastic containers with an integral tamper-evident feature. Typically, these containers include a cover hinged on the body. The cover is sealed to the body by overlapping the edge of the cover on the edge of the body. These types of plastic containers are sold as one-piece containers, commonly referred to as "clamshell" containers or packages.

[0010] In a type of hinged tamper-evident container, the lid and body each have an interlocking element, which is located on or near the lid edge and the body edge respectively, and is located at the place where the two edges meet when the container is sealed (that is, on the non-hinged side or part of the container). The interlocking element of the lid or body is usually located on the lug or flange extending from the edge of the lid or body. One or two lugs are attached to their respective edges by the fragile section of plastics. When the lid and body are placed in the initial sealing arrangement, the interlocking elements on or near the lid edge and the body edge engage and lock together. In order to open the container of the initial seal, the fragile part of one or two lugs must be torn off so as to release one or more lugs from the container. Since the interlocking sealing element is located on the lug, therefore tearing off one or more lugs from the container will make the locking mechanism invalid. The torn lug provides evidence that the container has been opened.

[0011] One disadvantage of the above-described prior art food containers is that the interlocking tabs can be cut from the container in a clean manner using scissors or another cutting utensil to remove any indication that the container has a tamper-evident mechanism. In view of the problems associated with incorporating a tamper-evident mechanism in the meeting edges of hinged containers, some manufacturers have incorporated tamper-evident features as part of the structure that forms or includes the hinge. In these containers, the container is designed to require severing near the hinge in order to unseal (initial opening) the container. This structure makes the hinge a disposable hinge.

[0012] It is known that there are multiple designs for tamper-evident food containers, which have a fragile hinge structure as an initial container opening mechanism. Almost all of these designs rely on the container having a specific, significant structure (e.g., a lug) protruding outward from the container to serve as a gripping or squeezing platform. The existence of this gripping or squeezing platform is for the user to apply a tearing force to the container to break a fragile (also referred to as "weakened" or "fragile") line or remove a material strip from the container. In some cases, the lug is constructed as an independent structure, forming a different angle with the other structures of the container. In other cases, the lug is a significant oversize portion of the existing structure of the container, typically a flange of a lid or body edge, which extends beyond a similar structure opposite to the lid or body edge to provide a dedicated gripping platform. Examples of these types of designs can be seen in U.S. Patents Nos. 9,944,436, 9,676,527, 9,493,277, 9,365,331, 9,132,942 and 7,568,589. Tamper-evident containers that avoid including a visible tab as a gripping portion near the hinge area typically have a square or "box-like" hinge structure that requires a significant vertical separation between the hinge structure originating from the lid edge and the hinge structure originating from the body edge.

[0013] One problem with all of the foregoing designs is that, in addition to the simple hinge structure, a large amount of additional material is required to construct a reliably functioning frangible hinge portion that can be used to initially open the sealed container. In addition, many hinge structures or their frangible mechanisms are made using complex arrangements of material folds and cuts that can only be made using complex tools or molding machinery. Therefore, there is a need in the art for a reclosable plastic food container that is easy for the end consumer to operate, combines reliable tamper evidence and defense against prying intrusion, and is manufactured using a minimum of material. Summary of the invention

[0014] The present invention meets the needs in the art and provides an aesthetically pleasing food container that is tamper-resistant, tamper-evident, and easy to use. In this regard, the food container of the present invention includes a plastic food container that is tab-free when viewed from the top, bottom, front, back, left, or right because it does not include obvious external or additional structure to serve as a grip. The container and its novel hinge area structure have a simple and clean appearance and, other than the inclusion of a line of weakness in the hinge panel, do not indicate that it has tamper-evident features. Thus, in contrast to prior art containers having overbuilt hinge area structures, the container of the present invention eliminates the significantly increased tabs, complex hinge area structures, and large vertical spans at the hinge ends.

[0015] The present invention has multiple embodiments, which are broadly described in this Summary of the Invention section and more particularly described in the Detailed Description of the Invention. The present invention is directed to a tamper-evident container with a novel hinge structure, a hinge structure, a line of weakness, and methods of forming the same.

[0016] In one embodiment, the present invention is directed to a tamper-evident container comprising a body and a lid. The body comprises a body edge and the lid comprises a lid edge. The lid is mountable to the body so that the container is in an initial sealing configuration. The initial sealing configuration is achieved by engagement of the lid edge with the body edge. A body hinge panel is coupled to the body edge and extends outwardly therefrom. A lid hinge panel is coupled to the lid edge and extends outwardly therefrom. The body hinge panel and the lid hinge panel have respective first and second side edges.

[0017] The container includes a line of weakness that: a) extends from a first side edge of a lid hinge panel partially across the lid hinge panel to a first point on the lid hinge panel; b) extends outward from the first point to a hinge, then across the hinge and inward from the hinge to a second point on the body hinge panel; and c) extends from the second point partially across the body hinge panel to a second side edge of the body hinge panel. When the container is in an initial sealed configuration, the line of weakness separates when a first upwardly directed force is applied to a first portion of the lid hinge panel and while a second portion of the lid hinge panel is maintained in a fixed position or moved downward. Notably, the separation of the line of weakness creates a first gripping portion and a second gripping portion that are separated from each other. Vertical displacement of the first gripping portion relative to the second gripping portion causes the mutually engaged edges to disengage.

[0018] Unlike most tamper-evident containers, the container of the present invention has no structure protruding outwardly from the edges of the interengaged lid and body, other than the lid hinge panel, body hinge panel, and hinge, when placed in the initial sealed configuration. In fact, the construction of the line of weakness is reliable and easy to operate, allowing the container to be manufactured without other lines of weakness on the lid hinge panel, body hinge panel, or the entire container. Unlike other tamper-evident containers, the separation of the line of weakness of the present invention does not produce pieces of material that break away from the container, such as tear strips, which are generally not ultimately recycled with the rest of the container or may present a swallowing or choking hazard to children and animals.

[0019] The present invention also relates to a method of thermoforming a tamper-evident container, the method comprising forming a lid from a portion of a single sheet of a preferably at least partially transparent plastic material. The lid has a lid edge. A body is formed from a portion of the single sheet. The body includes a body edge defining a periphery of the body. A foldable section of the container is formed from a portion of the single sheet. The foldable section joins the lid edge and the body edge, and the foldable section includes a lid hinge panel extending from the lid edge to a hinge, a body hinge panel extending from the body edge, and a hinge connecting the lid hinge panel to the body hinge panel.

[0020] The method includes forming a line of weakness that: a) extends longitudinally from an outside edge of a cover hinge panel across a portion of the cover hinge panel to a first point; b) extends transversely from the first point across the cover hinge panel to the hinge; c) extends across the hinge in a manner that crosses the hinge and then extends transversely from the hinge across the body hinge panel to a second point on the body hinge panel; and d) extends longitudinally from the second point across a portion of the body hinge panel to the outside edge of the body hinge panel. In a preferred embodiment, the method includes forming a first arcuate section of the line of weakness on the cover hinge panel near the first point to achieve a transition of the line of weakness from extending longitudinally on the cover hinge panel to extending transversely on the cover hinge panel. Similarly, the method may include forming a second arcuate section of the line of weakness on the body hinge panel near the second point to achieve a transition of the line of weakness from extending longitudinally on the body hinge panel to extending transversely on the body hinge panel.

[0021] The present invention also relates to a fragile line for a plastic food container and a method for forming the same. The plastic food container has a lid hinge panel connected to a lid edge, a body hinge panel connected to a body edge, and a hinge connecting the lid hinge panel to the body hinge panel. The fragile line includes a first length portion, a second length portion, and a third length portion; the first length portion extends from a first side edge of the lid hinge panel partially across the lid hinge panel to a first point; the second length portion extends outward from the first point on the lid hinge panel to the hinge, then vertically crosses the hinge, and then extends inward from the hinge to a second point on the body hinge panel; the third length portion extends from the second point on the body hinge panel to a second side edge on the body hinge panel. The rupture of the fragile line results in the creation of two adjacent gripping portions, one gripping portion attached to the lid edge and one gripping portion attached to the body edge. The gripping portions can be used to pull the lid off the body. Other inventive concepts and aspects of the present invention are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a rear perspective view of a preferred embodiment of the plastic container of the present invention in an initial sealed configuration.

[0023] Figure 2 is a left side view of the preferred embodiment container in an initial sealed configuration.

[0024] Figure 3 is a front view of a preferred embodiment container in an initial sealed configuration.

[0025] Figure 4 is a rear view of a preferred embodiment container in an initial sealed configuration.

[0026] Figure 5 is a top view of a preferred embodiment container in an initial sealed configuration.

[0027] Figure 6 is a bottom view of a preferred embodiment container in an initial sealed configuration.

[0028] Figure 7 is a front perspective view of a preferred embodiment of a plastic container of the present invention in a stowed configuration.

[0029] Figure 8 is a rear perspective view of a preferred embodiment container showing that the hinge area structure has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0030] Fig. 9 is a right side view of the preferred embodiment container showing that the hinge area structure has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0031] Fig.10 is a left side view of the preferred embodiment container showing that the hinge area structure has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0032] Fig.11 is a rear view of the preferred embodiment container showing that the hinge area structure has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0033] Fig.12 is a front view of the preferred embodiment container showing the front of the container when the hinge area structure at the rear of the container has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0034] Fig.13 is a top view of the preferred embodiment container showing that the hinge area structure has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0035] Fig.14 is a bottom view of the preferred embodiment container showing that the hinge area structure has been divided into two visible gripping portions that allow the lid to be separated from the body.

[0036] Fig.15 is a perspective view of the body of a preferred embodiment container in an open configuration with the lid removed from the body by using the newly created grip formed by rupturing the line of weakness to peel the lid from the body.

[0037] Fig.16 is a detailed side cross-sectional view of a hinge area structure of an initially sealed container including the container opening mechanism of the present invention, the container having an alternative embodiment rim structure and hinge area structure. DETAILED DESCRIPTION

[0038] Figure 1-16A preferred embodiment of the tamper-evident plastic container 1 of the present invention and its preferred features are depicted. As shown, the container 1 of the present invention includes a lid 2 and a body 20, which are attached to each other by a hinge 50 located on one side of the container. The hinge 50 includes a hinge axis H, and the lid 2 and the body 20 pivot (rotate) about the hinge axis H. The body 20 includes a bottom 28. In actual use, the outer surface of the bottom 28 of the body 20 is generally placed on a surface that is considered horizontal relative to the user (such as a tabletop). Therefore, the directional terms "vertical" and "horizontal" and the like are used relative to Figure 1-6 The orientation and configuration in which the lid is initially sealed to the body depicts the container 1 and its components and is for purposes of clarity and illustration only. Figure 1 FIG. 2 shows a rear perspective view of the container 1 when the container 1 is in an initial sealed state. Figure 1-4 In the perspective view and the front view, the cover 2 is "vertically" above the body 20. Directional terms "interior" and "inwardly" are used herein with respect to the container being described to refer to the direction from the body 20 to the interior of the container. Figure 1 The horizontal direction of the directional component of the geometric center of the container is represented by the vertical axis A represented in the figure. With this vertical axis as the reference, the directional terms "exterior", "periphery", etc. are used in this article relative to the described container to refer to the direction along the horizontal directional component away from the geometric center of the container. In addition, the terms "upward", "downward", etc. are used to describe the spatial relationship between the structures when the cover 2 of the container 1 is initially sealed on the body 20.

[0039] The cover 2 and the body 20 include a cover edge 3 and a body edge 21, respectively. Figure 7 As shown, the body 20 has an open upper end 30 defined by a body rim 21. The lid rim 3 preferably includes a peripherally projecting lid rim flange 6. The body rim 21 similarly preferably includes a body rim flange 24. The body 20 and lid 2 are connected at a hinge 50.

[0040] As shown in the figure, the preferred embodiment container 1 can present a loading configuration ( Figure 7 ), initial sealing configuration ( Figure 1-6 ), closed (unsealed) configuration ( Figure 8-14 ) and the open configuration ( Fig.15 ).exist Figure 7 In the loaded configuration, the rim 3 of the lid 2 and the rim 21 of the body 20 are not frictionally engaged around the periphery 15 of the container 1. The container 1 is moved from the loaded configuration to the initial sealed configuration by closing the lid 2 on the body 20 until the lid rim 3 is urged into a closed frictional engagement with the body rim 21. Figure 1-6 In the initial sealing configuration, the lid rim 3 and the body rim 21 are frictionally engaged and the tamper-evident weakness line 34 (discussed below) is intact. Figure 8-14In the closed configuration shown, the line of weakness 34 has been broken, but the lid 2 is closed on the body 20, with the lid rim 3 and the body rim 21 frictionally engaged. In the open configuration, the lid 2 is removed from the body 20. Fig.15 The body 20 is depicted wherein, after the cover has been removed from the body, a user would unfold the body to consume the food product contained therein.

[0041] As discussed more fully below, the container 1 is transformed from the initial sealed configuration to the closed configuration by breaking the weakening line 34 on the hinge panels 5, 23. Breaking the weakening line 34 allows the lid 2 to be peeled off the body 20 by pulling the lid rim 3 out of engagement with the body rim 21. Once the weakening line is broken, the lid 2 can be reclosed on the body 20 and then reopened without breaking the weakening line 34. Therefore, after opening from the initial sealed state, the container 1 can be reclosed by pressing the lid rim 3 into engagement with the body rim 21.

[0042] The lid 2 comprises a top portion 10. The top portion 10 comprises an outer surface 11 on which vent holes 13 are provided. The container 1 may comprise a lid sidewall 12 extending between the top portion 10 and the lid rim 3. The lid rim 3 extends circumferentially around the peripheral portion 4 of the lid 2. The body rim 21 similarly extends around the peripheral portion 22 of the body 20. Fig.16 Depicted are edge structural features of exemplary embodiments that render the embodiment container not only tamper-evident, but also tamper-resistant. To practice the invention, the container need not have Fig.16 The precise edge structure shown in FIG. Other edge structures may be used, such as those shown in other figures. Fig.16 In the preferred embodiment of the invention, the edges 3, 21 are joined into a sealed or closed configuration. In this regard, the container 1 includes joined edges 3, 21 that provide a friction fit therebetween that tightly closes the container and cannot be easily pulled apart without destroying the line of weakness 34 described in more detail. Fig.16 As shown, in a preferred embodiment, the lid edge 3 includes a lid edge bead 53, and the lid edge bead 53 includes a vertical lid edge inner wall 54 that descends downward, an upwardly extending lid edge outer wall 55, and a bead bottom section 56. The bead bottom section 56 extends from the bottom 57 of the lid edge inner wall 54 and bends into the bottom 58 of the lid edge outer wall 55. The flange 6 preferably extends from the outer wall 55 of the lid edge 3 to the lid hinge panel 5.

[0043] The body 20 includes a body rim 21 extending circumferentially around a peripheral portion 22 of the body 20. The body sidewall 29 extends from the bottom 28 to the rim 21. The body rim 21 includes a body rim rib 61, which includes a downwardly extending vertical inner wall 62, an upwardly extending outer wall 63, and a rib bottom section 64. The rib bottom section 64 extends from a bottom 65 of the downwardly extending vertical inner wall 62 to a bottom 66 of the upwardly extending outer wall 63. The flange 24 preferably extends from the outer wall 63 of the body rim 21 to the body hinge panel 23. The downwardly extending inner wall 62 and the upwardly extending outer wall 63 each include a concave structure that is configured to receive and frictionally engage the raised surfaces of the inner wall 54 and the outer wall 55 of the lid rim 3, respectively, when the container 1 is in a sealed or closed arrangement.

[0044] In one embodiment, the present invention relates to a tamper-evident container including a body 20 and a lid 2. The body 20 has a body peripheral portion 22, which includes a body edge 21. The lid 2 includes a lid peripheral portion 4, which includes a lid edge 3. The lid 2 can be mounted on the body 20 to bring the container 1 into a sealed configuration. The sealed configuration is achieved by engaging the lid edge 3 with the body edge 21 when the lid 2 is overlying the body 20. The initially sealed container 1 has a periphery 15 defined by the engaged edges 3, 21 and a folding area 48 including a hinge 50.

[0045] Container 1 also includes a body hinge panel 23, which is connected to the body edge 21 and extends horizontally outward from the body edge 21. The lid hinge panel 5 is similarly connected to the lid edge 3 and extends horizontally outward from the lid edge 3. The lid hinge panel 5 and the body hinge panel 23 have respective first side edges 7, 25 and second side edges 8, 26. The body hinge panel 23 and the lid hinge panel 5 are connected together at a hinge 50. The hinge 50 can be formed by any known method for forming hinges and hinged areas in plastic containers, including but not limited to scoring, thinning, embossing or intermittent perforations. When the container 1 is in the initial sealing configuration, the lid hinge panel 5 covers the body hinge panel 23 when it extends from the lid edge flange 6 to the hinge 50. The hinge 50 extends from the corresponding first side edges 7, 25 of the lid hinge panel 5 and the body hinge panel 23 to the corresponding second side edges 8, 26 of the lid hinge panel 5 and the body hinge panel 23. When in the initial sealed form, the lid hinge panel 5, the body hinge panel 23 and the hinge 50 together form a fold 48 (at Fig.16 When in the stowed configuration, the lid hinge panel 5, the body hinge panel 23 and the hinge 50 together form a foldable section 49 (in Figure 7 ).

[0046] The embodiment container 1 includes a line of weakness 34 (also referred to as a breakable joint or line of weakness) extending from a first side edge 7 of the lid hinge panel 5 partially across the lid hinge panel 5 to a first point 9 on the lid hinge panel 5. The line of weakness extends outwardly (line of weakness portion 35) from the first point 9 to the hinge 50, then downwardly and across the hinge 50, and then inwardly (line of weakness portion 36) from the hinge 50 to a second point 27 on the body hinge panel 23. The line of weakness 34 extends from the second point 27 partially across the body hinge panel 23 to the second side edge 26 of the body hinge panel 23. Due to its outwardly and inwardly directed portions 35, 36, the line of weakness 34 divides the fold 48 into adjacent first and second portions or sides 42, 43. In Figure 5 In the embodiment and orientation shown, the first side 42 is located to the right of the outwardly directed portion 35 of the weakened line 34 on the hinge panel 5. This is merely exemplary. The attachment of the lid hinge panel 5 to the lid edge 3 on the first side 42 of the fold 48 is continuous and is not separated from the lid edge 3 by the weakened line 34. Figure 6 As shown, similarly, the body hinge panel 23 of the second side 43 of the fold 48 is continuously attached to the body edge 21 and is not separated from the body edge 21 by the weakening line 34 .

[0047] Breaking the fragile line 34 is simple and does not require awkward manipulation or positioning of the container 1. To break the fragile line 34, the user only needs to grasp the first side 42 of the fold 48 with one hand and grasp the second side 43 of the fold 48 with the other hand. When an upward force is applied to the first side 42 of the fold 48 and the second side 43 is held in place or guided downward, the fragile line 34 separates. When the fragile line 34 breaks, the fold 48 separates into the first and second adjacent gripping portions 46, 47. In other words, the first side 42 of the fold 48 becomes the first gripping portion 46, and the second side 43 of the fold 48 becomes the second gripping portion 47. As shown in the figure, a portion of the lid hinge panel 5 on the first gripping portion 46 remains attached to the lid rim 3. Similarly, a portion of the body hinge panel 23 on the second gripping portion 47 remains attached to the body rim 21. To remove the cover 2 from the body 20 , the user simply peels the cover 2 off the body 20 by pulling the first grip portion 46 and the second grip portion 47 vertically away from each other.

[0048] Describing the present invention further, it can be seen that the tamper-evident container 1 includes a body 20 and a lid 2. The body 20 has a body peripheral portion 22 defining an open upper end 30 of the body 20. The body peripheral portion 22 includes a body rim 21. The lid 2 includes a lid peripheral portion 4, which includes a lid rim 3. The lid 2 can be mounted on the body 20, and the lid 2 covers the open upper end 30 of the body 20 to bring the container 1 into an initial sealed configuration, which is achieved by the interlocking engagement of the lid rim 3 around the entire periphery 15 of the container 1 with the body rim 21. The interlocking engagement is releasable and reengageable to open and reclose the container 1.

[0049] The body hinge panel 23 extends outward from the body edge 21. The lid hinge panel 5 extends outward from the lid edge 2. The lid hinge panel 5 and the body hinge panel 23 have respective first side edges 7, 25 and second side edges 8, 26. The hinge 50 pivotally connects the body hinge panel 23 and the lid hinge panel 5. The body hinge panel 23 extends between the body edge 21 and the hinge 50. The lid hinge panel 5 extends between the lid edge 3 and the hinge 50. The hinge 50 extends from the first side edges 7, 25 of the lid hinge panel 5 and the body hinge panel 23 to the second side edges 8, 26 of the lid hinge panel 5 and the body hinge panel 23.

[0050] The container 1 also includes a line of weakness 34 extending from a first side edge 7 of the lid hinge panel 5 partially across the lid hinge panel 5 to a first point 9 on the panel. The line of weakness 34 extends outwardly from the first point 9 to the hinge 50, then across the hinge 50 and inwardly from the hinge 50 to a second point 27 on the body hinge panel 23. The line of weakness extends from the second point 27 partially across the body hinge panel 23 to a second side edge 26 of the body hinge panel 23. With this arrangement, when the container is in the initial sealed configuration, only a portion of the line of weakness is located on the lid hinge panel, and only a portion of the line of weakness is located on the body hinge panel.

[0051] When a force directed upward is applied to the first side 42 of the folded lid hinge panel and the body hinge panel 5, 23 relative to the second side 43 of the folded lid hinge panel and the body hinge panel 5, 23 (folded at the hinge 50), the fragile line 34 separates. As shown in the figure, the rupture of the fragile line 34 produces a first gripping portion 46, which is adjacent to the second gripping portion 47 in the horizontal direction but separated from the second gripping portion 47. The first gripping portion 46 is attached to the lid 2 and the second gripping portion 47 is attached to the body 20. After the fragile line 34 is broken, the body edge 21 and the lid edge 3 remain intact and engaged. By pulling the first gripping portion 46 vertically away from the second gripping portion 47, the lid 2 is removed from the body 20. The container 1 can be reclosed after the fragile line 34 has been broken. Further, the container 1 in the sealed configuration requires a first separation force to break the fragile line. Rupture of the line of weakness 34 separates the lid 2 and body 20 into two distinct components which are frictionally engaged at their peripheral edges 3, 21. After rupture of the line of weakness 34, a second separation force is required to disengage the mutually engaged peripheral edges of the lid and body.

[0052] Any one or both of the cover hinge panel 5 or the body hinge panel 23 may have knurling, additional texture or finger rests to provide additional gripping for the user when holding each side 42,43 or gripping portion 46,47. In the depicted embodiment, the body hinge panel 23 includes a finger rest 70. This is merely an optional feature. Making the hinge panel without such finger rests will make the container look cleaner. It is worth noting that in the initial sealing configuration, in addition to the cover hinge panel, the body hinge panel and the hinge, the container 1 does not have a structure protruding outward from the mutually engaged lid and body edge. This makes the embodiment container look like an ordinary container without obvious tamper-evident features. Therefore, the container 1 appears to be different from numerous tamper-evident containers with projections and complex structures required for cutting off the fragile portion at the hinge area. In addition, the hinge panels 5, 23 and the container 1 do not have any fragile lines except line 34, which provides a simple opening mechanism and minimal unsightly surface markings and discontinuities. Additionally, breaking the line of weakness 34 does not produce unattached pieces of material, such as strips, that must be discarded.

[0053] In the depicted preferred embodiment, the line of weakness 34 includes a first arcuate segment 44 located at a first point 9 that gently redirects the line of weakness 34 from a line running longitudinally across the hinge panel 5 to a line pointing outward and running transversely across the long axis of the hinge panel 5. This arcuate segment allows the line of weakness 34 to not only change direction, but to do so in a smooth manner, so that the lid hinge panel 5 does not include any internal corners that would provide any alternative tear-off points to bypass the opening mechanism, and ensures that the line of weakness 34 breaks smoothly when the first side 42 of the fold 48 is separated from the second side 43 of the fold 48. In addition, the line of weakness 34 extends vertically downward across the hinge 50 and intersects the hinge 50. The line of weakness 34 preferably includes a second arcuate segment 45 at a second point 27 on the body hinge panel 23, which provides similar advantages and functions as the first arcuate segment 44.

[0054] The present invention also relates to a fragile line for a plastic food container having a lid hinge panel connected to a lid edge, a body hinge panel connected to a body edge, and a hinge connecting the lid hinge panel to the body hinge panel. The fragile line 34 of the present invention extends from a first side edge 7 of the lid hinge panel partially across the lid hinge panel to a first point 9. At the first point 9, the fragile line 34 extends outward to the hinge 50, then vertically crosses the hinge 50, and then extends inward from the hinge to a second point 27 on the body hinge panel. The fragile line of the present invention extends from the second point to the second side edge on the body hinge panel. The rupture of the fragile line results in the creation of two adjacent gripping portions 46, 47, one attached to the lid edge and one attached to the body edge.

[0055] The present invention also relates to a method for thermoforming a tamper-evident container. The method includes forming a lid 2 from a portion of a single sheet of at least partially transparent plastic material. The lid 2 is formed with a lid edge 3 that defines a periphery 4 of the lid 2. The lid edge 3 is formed to be connected to a lid hinge panel 5. In a preferred embodiment method, the lid edge 3 is formed with an outwardly protruding lid edge flange 6, and the lid hinge panel 5 extends from the lid edge flange 6. The method also includes forming a body 20 from a portion of the single sheet. The body 20 includes a body edge 21 that defines a periphery 22 of the body 20. The body edge 21 is connected to a body hinge panel 23. The body edge 21 preferably includes a body edge flange 24 that protrudes outward. In the preferred embodiment method, the body edge 20 is formed with an outwardly protruding body edge flange 24, and the body hinge panel 23 extends from the body edge flange 24. The method comprises forming a hinge 50 from a portion of the single sheet, the hinge 50 joining the lid hinge panel 5 to the body hinge panel 23. The foldable section 49 comprises the hinge 50, the lid hinge panel 5 and the body hinge panel 23.

[0056] The embodiment method also includes forming a line of weakness 34 that: a) extends from the first side edge 7 of the lid hinge panel 5 partially across a portion of the lid hinge panel 5 to a first point 9; b) extends from the first point 9 to the hinge 50; c) at the hinge 50, extends across the hinge 50 in a manner that crosses the hinge 50 and then extends from the hinge 50 to a second point 27 on the body hinge panel 23; and e) extends from the second point 27 partially across the body hinge panel 23 to a second side edge 26 of the body hinge panel 23. Preferably, the container is formed such that: when the lid is closed on the body, the container has no structure protruding outwardly from the interengaged lid and body edges other than the lid hinge panel, the body hinge panel and the hinge. It is also preferred that the container is formed such that: none of the lid hinge panel, the body hinge panel or the container has any other line of weakness. It can also be seen that the line of weakness 34 is completely horizontally spaced inboard of the hinge or hinge axis, except for a small section where it vertically contacts the hinge and cuts it transversely into two horizontal sections.

[0057] Containers constructed in accordance with the present invention may be manufactured in a variety of shapes and sizes and are preferably made of a resin or plastic material, including but not limited to polystyrene, polyethylene, polypropylene, polyvinyl chloride, or polyethylene terephthalate ("PET"). The container is preferably thermoformed, but may be blow molded or injection molded. The container lid and body may be transparent or translucent, and in either case may be colored. Furthermore, the container is preferably polygonal, but may be of any shape.

[0058] Having described the present invention in detail, those skilled in the art will appreciate that modifications can be made to the present invention without departing from its spirit. Therefore, the scope of the present invention is not intended to be limited to the specific embodiments illustrated and described.

Claims

1. A container, comprising: a body, the body comprising a body hinge panel; as well as a cover sealably engaged with the body, the cover including a cover hinge panel; wherein the body hinge panel and the cover hinge panel are hinged together along a hinge line to form a foldable section, the foldable section having a first side edge, a second side edge, and a fragile line extending between the first side edge and the second side edge, wherein the fragile line extends across each of a portion of the body hinge panel, the hinge line, and a portion of the cover hinge panel while extending between the first side edge and the second side edge.

2. The container according to claim 1, wherein When the body and the cover are sealed together, the foldable section forms a folded portion divided into a first side and an adjacent second side by the weakening line, and the weakening line can be broken by applying a force to at least one of the first side and the second side so as to separate the first side and the second side.

3. The container according to claim 2, wherein: The line of weakness is breakable to separate the portion of the body hinge panel from the body and to separate the portion of the lid hinge panel from the lid.

4. The container according to claim 2, wherein: The first side includes the portion of the body hinge panel and a second portion of the lid hinge panel continuously attached to the lid, and the second side includes the portion of the lid hinge panel and a second portion of the body hinge panel continuously attached to the body.

5. The container according to claim 2, wherein: When the weakened line is broken to separate the first side from the second side of the folded portion, the body and the cover remain sealed together.

6. The container according to claim 1, wherein The hinge line defines a weak tear pattern that can break to separate the body hinge panel from the lid hinge panel.

7. The container according to claim 1, wherein The body hinge panel is integrally formed with the lid hinge panel.

8. The container according to claim 7, wherein: The cover, the body and the foldable section are formed from a single sheet of material.

9. The container according to claim 8, wherein The sheet is an at least partially transparent plastic material.

10. The container according to claim 1, wherein The body comprises a body edge having a body edge rib, the cover comprises a cover edge having a cover edge rib, and the body edge and the cover edge can be joined together by friction fit between the body edge rib and the cover edge rib.

11. A container, comprising: a body including a body rim extending around a peripheral portion of the body; a cover, the cover comprising a cover edge extending around an outer peripheral portion of the cover, the cover edge being sealably engaged with the body edge to seal the cover and the body; a body hinge panel extending outwardly from the body edge and having a first side edge and a second side edge; a cover hinge panel, the cover hinge panel extending outward from the cover edge and having a first side edge and a second side edge, the cover hinge panel and the body hinge panel being hinged together along a hinge line; A line of weakness extends between the first side edge of the body hinge panel and the second side edge of the cover hinge panel, the line of weakness extending across the hinge line while extending between the first side edge of the body hinge panel and the second side edge of the cover hinge panel.

12. The container according to claim 11, wherein The body hinge panel and the lid hinge panel form a foldable section that can be folded around the hinge line. When the body and the lid are sealed together, the foldable section forms a folded portion divided into a first side and an adjacent second side by the fragile line. Each of the first side and the second side includes a portion of the body hinge panel and a portion of the lid hinge panel. The fragile line can be broken by applying a force to at least one of the first side and the second side of the folded portion so as to separate the first side from the second side.

13. The container according to claim 12, wherein The portion of the body hinge panel on the first side is continuously attached to the body rim and the portion of the lid hinge panel on the second side is continuously attached to the lid rim.

14. The container according to claim 12, wherein: When the line of weakness is broken, the first side forms a first grip portion and the second side forms a second grip portion, wherein each of the first grip portion and the second grip portion remains on the container and enables the lid to be disengaged from the body.

15. The container according to claim 11, wherein The body edge comprises a body edge rib, the cover edge comprises a cover edge rib, and the body edge and the cover edge can be joined together by friction fit between the body edge rib and the cover edge rib.

16. The container according to claim 15, wherein: The cover edge rib has an inner wall and an outer wall connected by a bottom section; and The body edge rib has an inner wall and an outer wall connected by a bottom section, wherein the inner wall, the outer wall and the bottom section of the body edge rib define a concave structure sized and shaped to receive and frictionally engage the cover edge rib.

17. The container according to claim 16, wherein: The inner wall and the outer wall of the cover edge rib have a convex shape; and The inner wall and the outer wall of the main body edge rib have a concave shape, which is complementary to the convex shape of the inner wall and the outer wall of the cover edge rib, and enables the inner wall and the outer wall of the main body edge rib to respectively receive and frictionally engage the inner wall and the outer wall of the cover edge rib.

18. The container according to claim 11, wherein The hinge line defines a weak tear pattern that can break to separate the body hinge panel from the lid hinge panel.

19. The container according to claim 11, wherein The body hinge panel is integrally formed with the lid hinge panel.

20. A container comprising: a body, the body comprising a body edge extending around a peripheral portion of the body, the body edge comprising a body edge rib having an inner wall and an outer wall connected by a bottom section; a cover, the cover comprising a cover edge extending around a peripheral portion of the cover, the cover edge comprising a cover edge rib, the cover edge rib having an inner wall and an outer wall connected by a bottom section, wherein the inner wall and the outer wall of the cover edge rib are frictionally engaged with the inner wall and the outer wall of the body edge rib, respectively, so that the cover edge is sealingly engaged with the body edge; a body hinge panel, the body hinge panel extending outwardly from an edge of the body; as well as A cover hinge panel, the cover hinge panel extends outward from the cover edge, the cover hinge panel and the body hinge panel are hinged together along a hinge line to form a foldable section, the foldable section includes the body hinge panel, the hinge line and the cover hinge panel, the foldable section has a first side edge, a second side edge and a fragile line extending between the first side edge and the second side edge, and the fragile line extends across the hinge line during the extension between the first side edge and the second side edge.

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