Abstract:
A rigid polymer domed food container system suitable for heated food products is described. Recessed vents in the lid of the food container systems permit stacking of multiple container systems while allowing heated gases to escape without restriction. Other features of this container system include the retention of food product within the central region of the tray, rigidized handholds to allow the consumer to lift the heated container, and a releaseably lockable snap-fit grip mechanism that facilitates opening of the container system among other things.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to container system configurations for foodstuff. More particularly, the invention relates to a food packaging containment system that is suitable for heated food items such as rotisserie chicken and the like, and includes a tray compartment and a lid member. The container system preferably includes tamper-resistant features, as well as tamper-evident features that visually evidence unauthorized ingress if interfered either inadvertently or with the intent to cause harm.  
       BACKGROUND OF THE INVENTION  
       [0002]     Retail markets have utilized rigid and flexible plastic containers to protect and display both perishable and fragile food items such as sandwiches, salads and bakery items. These traditional roles of plastic packaging are now the minimum expected standards, and the requirements placed on plastic food packaging continue to expand as increasing demands are placed upon it. Presentation, brand presence, consumer desires, added value to enhance commercial competitiveness, differentiation, imagery and psychology has resulted in the design and application of plastic packaging becoming more challenging. Convenience and versatility continue to shape the future of packaging, with consumers gravitating toward packaged convenience items that minimize the impact on their behavior. This has forced packaging manufacturers to include social and environmental considerations into their development process. The provision of multiple compartments in a variety of shapes and utilities in rigid plastic containers has been one such direction that packaging manufacturers have been pursuing.  
         [0003]     Rigid plastic food containers are typically manufactured from Polystyrene, Polypropylene, Polyethylene Terephthalate (PET), Polylactide, Polyvinyl Chloride (PVC), or other rigid polymers. They generally comprise either of two-parts—a tray and lid—or they may be a one-piece construction with a hinge that modifies one portion of the container to act as the tray and the other connected portion to act as a lid. Furthermore, they are available in a variety of shapes and cross-sections—circular, rectangular, square, and elliptical, etc.  
         [0004]     The use of such plastics for holding heated food has gained favor with the rotisserie chicken being one of the fastest growing applications. However, many currently available food packages have not been designed to cater to the consumer&#39;s needs as related to the handling of such container systems for heated foods. Heating of the container contents result in high temperature fluids and gases result in increased pressure build-up, can be painful to the touch. Such constraints also place limitations on the logistical elements such as containerization of large quantities of heated food product. This invention provides for a unique approach that achieves this objective.  
       SUMMARY OF THE INVENTION  
       [0005]     In a preferred embodiment of the invention, the tray and lid members of the container system possess edges that are designed to mate with and be releaseably lockable to each other. The releaseably lockable mechanism is usually accomplished using a snap-fit grip and the elements comprising the releaseably lockable snap-fit grip enable a force fit between the lid member and the tray member of the container system. In this embodiment, the releaseably lockable mechanism is further designed to have a uniform cross-section along its entire periphery and is specially configured to hinder condensate from escaping at the lid-tray interface.  
         [0006]     In another embodiment of the invention, opposing sides of the lid and tray members are extended to act as handholds to help the consumer lift the heated container system. Generally, markets that offer heated food products such as rotisserie chickens in plastic container system either provide gloves for the consumer to handle the heated package or the heated package is placed in a cardboard lifting cradle with a handle that resides over the top of the lid member of the container system. This embodiment of the present invention eliminates the need for such devices and additionally enables the food manufacturer and retailer to stack the container systems.  
         [0007]     Without venting, expansion of the container as a consequence of heated gases including steam would cause the lid to pop from the tray member. Vents permit the release of these trapped vapors. In another embodiment of the invention, the vents are recessed into the top of the lid member. The recessed vents serve to permit stacking of the containers without blocking of the vents, thus allowing the food retailer additional space savings while maintaining the display effectiveness of the container system.  
         [0008]     In another embodiment of the invention, the lid of the container system is secured to the tray by means of a tamper-evident tamper-resistant snap-fit grip mechanism. Rigid plastic tamper-evident packaging generally provide visible-to-the-naked-eye indication that a container has been interfered with, that is, it had previously be opened and then re-closed prior to purchase. This invention is a novel plastic packaging solution that improves significantly on the convenience and therefore marketability of food product.  
         [0009]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0011]      FIG. 1  is an isometric view of an embodiment of the present invention showing the disassembled lid and tray members.  
         [0012]      FIG. 2  is a plan view of the container system in  FIG. 1 .  
         [0013]      FIG. 3  is a plan view of the bottom of the tray member in  FIG. 2 .  
         [0014]      FIG. 4  is an enlarged perspective view of a recessed vent depicted in  FIG. 1 .  
         [0015]      FIG. 5  is a side view of the assembled container system in  FIG. 1 .  
         [0016]      FIG. 6  is an enlarged cross-sectional view of the releaseably locking mechanism and handle of the container system in taken in the  5 - 5  plane in  FIG. 2 .  
         [0017]      FIG. 7  is a side view of an embodiment of the present invention.  
         [0018]      FIG. 8  is a cross-sectional view of the container systems in  FIG. 2  taken along the line  7 - 7  in  FIG. 2 .  
         [0019]      FIG. 9  is a fragmentary sectional view of the releaseably locking mechanism of the container system taken in the Y-Y plane of  FIG. 8 .  
         [0020]      FIG. 10  is a fragmentary sectional view of a portion of the tray member of the container system taken in the Z-Z plane of  FIG. 8 .  
         [0021]      FIG. 11  is cross-sectional view of two container systems each similar to that depicted in  FIG. 8  illustrating how the food container systems is stacked. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, this embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.  
         [0023]     Referring to the drawings and in particular to  FIGS. 1 &amp; 2 , there is shown a dome-shaped, rigid polymer construct food container system according to the present invention. The food container system includes a lid member  2  and tray member  4  which forms the primary recess into which heated foodstuff, such as a rotisserie chicken, is placed.  
         [0024]     The lid and tray members  2 ,  4  of the container system can be molded, through known thermoforming manufacturing means, from a single sheetline of polymer material work piece into a predetermined shape and thickness as required. The lid and tray members  2 ,  4  of the container system may also be formed, through known thermoforming manufacturing means, into a curvilinear geometry to thereby provide the end user with a variety of polygonal shapes. In the container system of the invention, the lid member  2  has geometry that permits even mating with the tray member  4  at their peripheral edge. Additionally, mating between lid member  2  and tray member  4  is releaseably lockable and achieved using a snap-fit grip  25 . As shown, the releaseably lockable mechanism is a slotable mechanical interface wherein the tray member snap-fit grip component  33  is the male element and the lid member snap-fit grip component  31  is the female element. Rib element  16  increases the rigidity and strength of the in the lid member handhold  15 . Separating the lid member  2  from the tray member  4  is facilitated by pulling the lid member handhold  15  away from the tray member handhold  17 . Also shown are raised ribbed sidewalls  10 ,  11  in the lid and tray members that improve the overall rigidity of the container system.  
         [0025]     Also shown is the planar surface  12  of the lid member  2  that is bordered by a raised rib periphery  3 ,  3 ′ with the raised rib periphery  3 ,  3 ′ separated at their ends by recessed vents  14 ,  18 . In addition to improving the structural integrity of the lid member, the raised rib periphery  3 ,  3 ′ serves to hold in place the tray member  4  of a second identical container system that may be stacked on the lid member  2 . This feature is illustrated in greater detail in  FIG. 11 . The lid member  2  may be made from material that are dissimilar from the material used to make the tray member  4  so that when temperatures are elevated, dissimilar coefficients of thermal expansion of the lid member  2  and the tray member  4  increase the effectiveness of the mechanically fastening of the releaseably lockable snap-fit grip and thereby promote the retention of heated gases and condensate. The raised retaining ribs  38 ,  38 ′ is designed restrict movement of the food product contents generally so that they stay within the central portion of the tray member  4 .  
         [0026]      FIG. 3  further illustrates the complementary female grooved elements  21 ,  22  &amp;  24  that form a mechanical fit with the raised rib  3  of the lid member  2 . The female grooved element  21  sitting on the lid member planar surface  12  is illustrated in  FIG. 2 . The female grooved elements  22 ,  24  are straddled by the raised rib periphery  3 ,  3 ′ and sit above but are not in mechanical contact with the recessed vents  14 ,  18 .  
         [0027]     The extended flange lip  23  of the tray member is defined by the points  13  and  54 , and extending outwards to points  9  and  39 , and raised rib  6 , together form the tray member handhold  19 . Similarly, the extended flange lip  37  of the tray member defined by the points  27  and  55 , and extending outwards to points  29  and  50 , and raised rib  8 , together form the tray member handhold  17 . This design significantly increases the rigidity and the strength of the handholds  17  and  19  of the tray member  4 . Together with the lid member handhold  15 , tray member handholds  17 ,  19  give the consumer increased control when both lifting and opening the heated container system.  
         [0028]     Turning to  FIG. 4 , shown therein is a fragmentary enlarged view of the recessed vent  18  of the present invention. The recessed vent  18  is straddled by the raised edge  28  of the raised rib periphery  3  and the raised edge  30  that leads to the planar surface  12  of the lid member  2 . For illustrative purposes, venting means is achieved through the flap  26  comprising the recessed vent  18 ; however, any suitable perforation large enough to permit hot gas to pass through would suffice.  
         [0029]     Turning to  FIGS. 5 and 6 , therein is shown a side view of the embodiment of present invention in  FIG. 1  and the enlarged fragmentary cross-section of the lid and tray members&#39; handhold elements  15 ,  17 . Also shown is the releaseably lockable snap-fit grip mechanism  25  that secures the lid member  2  and tray member  4  together when the container system is assembled. The raised rib element  16  ends on an flat edge  32  that is vertically displaced from tray member edge  34  to facilitate gripping by fingers and further provides a gap  36  to allow the consumer to pry open and separate the lid member  2  from the tray member  4 .  
         [0030]     Turning to  FIG. 7 , therein is shown a side view of a variation of the embodiment of the present invention as in  FIG. 1 . As shown, the container system is a single piece construction with its lid member  2  and tray member  4  hingeably attached with a hinge  35 .  
         [0031]     Turning now to  FIG. 9 , therein is shown an enlarged cross-sectional view of the releaseably lockable snap-fit grip  25  of the present invention. The elements comprising the releaseably lockable snap-fit grip  25  are integral parts of the lid member  2  and tray member  4 , wherein the tray member snap-fit grip component  33  is the male element that slots into the female lid member snap-fit grip component  35  element. Improved retention of the fluids and hot gases is achieved by the five choke points  42 ,  44 ,  46 ,  48  &amp;  49 . The choke points serve to hinder the passage of fluids or gases from the interior of the container system. The planar surface  51  lying between choke points  42  and  46  but coincident with choke point  44 , and the planar surface  53  lying between choke points  46  and  49  but coincident with choke point  48  are angled relative to each other making a concave with angle Ω between the two surfaces such that a tight fit is achieved. Edges  47  and  49  of the tray member  4  are incident with the choke points  42  and  49 , and as shown, the edges are vertically displaced by a distance L, wherein the interior edge  47  is lower relative to the exterior edge  49 . In order to remove the lid member  2  from the tray member  4 , the lid edge  43  is lifted up. The differential ledge height L serves to facilitate the opening of the container system by permitting the lid member element of the snap-fit grip to pivot about the ledge  47 .  
         [0032]     Turning now to  FIG. 10 , therein is shown an enlarged cross-sectional view of a portion of the tray member  4  illustrating the raised rib edge  38  that is located in the interior near the periphery of the tray member  4 . The raised ribs  38 ,  38 ′ as shown in  FIG. 1  is designed encourage the food product to remain within the central portion of the tray  4 . The greater the height M of the raised rib edge  38 , the greater its ability to encourage the food product to remain within the central portion of the tray  4 . The height of raised rib edge  38  is limited by the thermoforming or other manufacturing process used to produce the tray member  4 .  
         [0033]     Also shown in  FIG. 10  is the sloped portion  20  of the tray member  4  lying between the raised rib edge  38  and the tray footing  40 . The slope is at an angle β from the horizontal plane and is designed to encourage the hot condensate and other fluids to flow toward the tray footing  40 . The sloped portion  20  of the tray member  4  is also identified in  FIG. 1  and  FIG. 3 .  
         [0034]     Turning finally to  FIG. 11  therein is shown a cross-sectional view of a first container system  45  of the present invention that is stacked on top of a second container system  43  of the present invention. The first container system  45  is held in place by a mechanical fit between raised rib peripheries  3 ,  3 ′ of the lid member  2  of the second container system  43  into which the complementary raised ribs that form the foot  40 ,  40 ′ of the tray member  4  of the second container system  45  slotably interfaces.  
         [0035]     Plastic packaging sealing mechanisms generally include snap-fit grips that effectively provide a leak-proof seal that allows the consumer to open, close and releaseably lock the container system multiple times. Some of the advantages of this aspect of the invention are that food freshness can be extended then would otherwise occur without sealing and spillage of the food content is prevented.  
         [0036]     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.