Abstract:
A container clearly indicates that it has been opened after a store clerk loads food into the base of the container and closes a covering of the container onto the base. The covering ( 16 ) includes a peripheral cover portion ( 22 ) that becomes fixed to a peripheral base portion ( 32 ) when the clerk initially closes the container. To thereafter open the container, a person forcefully lifts a tab ( 30 ) on the covering to tear the covering along a long tear line ( 26 ) that separates the peripheral cover portion ( 22 ) from a lid ( 24 ) formed by a radially inner covering portion. The base ( 12 ) is fixed to the peripheral covering portion ( 22 ), and together they form a base device ( 40 ). After the lid has been torn free of the peripheral covering portion, the lid can be closed and latched to the base device and then can be easily opened again. The container is supplied to the store with an adhesive strip ( 34 ) that the clerk activates by shining ultraviolet light (UV) at the adhesive after he/she places the loaded and initially closed container in a UV chamber ( 86 ), or mechanical latches with tabs engaging shoulders can be used.

Description:
CROSS REFERENCE 
     Applicant claims priority from U.S. Provisional Patent Application Ser. No. 60/689,394 filed Jun. 10, 2005. This is a continuation of Ser. No. 11/446,622 filed Jun. 5, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     Food is often placed in a transparent container that includes a base with an upwardly-opening cavity that holds food and with a lid that closes the cavity. Buyers want to be assured that, after the food was placed in the container as by a clerk at the food store (who often wears plastic gloves to avoid food contamination), that the container has not been opened. There is a possibility that another customer has secretly opened the container enough to taste a bit of the food before closing it (and possibly leaving germs from his/her finger in the food). Potential buyers want to be assured that this has not happened. A container constructed by the container manufacturer that allowed a clerk at a store to easily close the container and lock it closed, and that thereafter clearly indicated to a potential customer whether or not the container has been opened since it was first closed by the clerk, would be of value. The clear indication of tampering is especially useful for containers that hold food, but is also useful for containers that hold many small nonfood items to assure a customer that some of the original items have not been taken. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the invention, a container is provided of the type that includes a base and covering formed of plastic sheeting, which allows the container to be initially closed as by a store clerk, and which thereafter prevents the container from being casually and secretly opened. The container can be initially opened only by applying a large sustained pull force to separate a lid of the covering from a peripheral cover portion that is fixed to a peripheral base portion of the base. After being initially opened, the lid can be easily replaced on the base (which is now a base device that includes the peripheral cover portion) and the lid latches itself closed on the base and can be easily opened. 
     The container is supplied by the manufacturer so when the covering is initially closed on the base, as by a store clerk pushing the covering onto the base and activating an adhesive, the peripheral cover portion becomes fixed to a peripheral portion of the base. The covering includes a tear line, such as a line of perforations, that separates the peripheral cover portion from the lid. After such initial closing of the container, initial opening of the container requires that the lid be lifted to tear it free of the peripheral cover portion. The fact that the lid has been torn free of the peripheral cover portion, is obvious when looking at the container, so a potential buyer of the food-holding container is assured that food in the container has not been touched by another customer. 
     The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top isometric view of a container of the present invention. 
         FIG. 2  is a plan view of the container of  FIG. 1 . 
         FIG. 3  is a sectional view of a portion of a container taken on line  3 - 3  of  FIG. 1 , but with the base and covering separated prior to initial closing of the container. 
         FIG. 4  is a view of the container similar to the view of  FIG. 3 , but with the base and covering after they have been initially closed and before they have been initially opened. 
         FIG. 5  is a view of the container similar to the view of  FIG. 4 , after the container has been initially opened following its initial closing, showing that the lid of the covering has been separated from a base device formed by the base and peripheral cover portion. 
         FIG. 6  is a sectional side view of the container of  FIG. 1 , after food has been loaded into the base, but before the covering has been closed on the base, and with two additional strips of adhesive. 
         FIG. 7  is a view similar to that of  FIG. 6 , showing the covering as it approaches the base during the initial closing of the container. 
         FIG. 8  is a view similar to that of  FIG. 7 , but with the covering lying in the closed position on the base, and during the application of ultraviolet light to activate a quantity of adhesive that fixes the covering to the base. 
         FIG. 9  is an exploded view of a portion of a covering and of a base, which is similar to that of  FIG. 3 , but with the hat parts of the cover and base peripheral portions upside-down from the positions of  FIG. 3 . 
         FIG. 10  is an exploded view of a portion of a covering and of a base, which is similar to that of  FIG. 9 , but with additional latch parts for assuring good adhesion of the covering to the base. 
         FIGS. 11 and 12  are partial sectional views of a covering and a base of another embodiment of the invention, wherein the covering and base are fixed together only by mechanical parts of each of them. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a container  10  which includes a basically rectangular base  12  with a bottom  13  four sides  15 , that forms an upwardly opening cavity  14 , and a covering  16  that covers the base. Both the base and covering are formed of plastic sheeting, such as by two sheets of transparent plastic that have been vacuum formed, each of 0.020 inch thickness. The container has a vertical axis  20 . The covering includes a peripheral cover portion  22  that is fixed to the base, and also includes an inner cover portion or lid  24  with a majority of the lid lying radially inward (with respect to axis  20 ) of the peripheral cover portion. A tear line  26  lies between the peripheral cover portion  22  and the lid  24 . A lift tab  30  can be pulled up forcefully (e.g. with a force of 10 pounds) while the peripheral base portion  22  is held down, to tear the tear line and thereby separate the lid from the peripheral cover portion.  FIG. 3  also shows skirts, or primarily horizontal flanges  22 ′,  32 ′ with free outer edges  23 ,  25  on the base and outer cover portion, with the base flange outer edge  25  lying below the cover flange outer edge  23 .  FIG. 4  shows that the vertical gap between the flanges  22 ′,  32 ′ is a plurality of times the thickness of the sheet plastic. 
       FIG. 3  shows the tear line  26  that separates the peripheral cover portion  22  from the lid  24 . The base has a peripheral base portion  32  to which the peripheral cover portion  22  can be fixed, by a quantity of adhesive  34 . The base also has a radially inner base portion  36 . After the peripheral cover portion  22  has been fixed to the peripheral base portion  32 , and the lid has been torn free along the tear line  26 , the lid  24  is free as shown in  FIG. 5 . The peripheral cover portion  22  remains on the base as shown in  FIG. 5 . Together, the base  12  and the peripheral cover portion  22  form a base device  40 . The lid can be repeatedly closed on the base device and easily lifted off of it. 
     As shown in  FIG. 3 , the container has a latch  42  that includes a lid latch part  44  that can readily latch to a base latch part  46 . The lid latch part has a radially outwardly (O) extending projection  47  (i.e. generally away from the container axis), while the base latch part has a radially-inward (I) opening recess  49 . The latch in its closed position in  FIG. 4 , prevents unlatching unless inclined shoulders  51 ,  53  on the base and lid are deflected horizontally. The inclined shoulders allow the lid to be pulled free of the base by applying a moderate upward force such as 3 pounds to the lift tab. 
       FIG. 3  shows that the peripheral cover portion  22  includes a covering hat part  50  that includes a flat primarily horizontal hat middle wall  52  and radially inner and outer hat side walls  54 ,  56  that are flat and extend primarily vertically. The peripheral base portion  32  has a base hat part  60  that includes a flat primarily horizontal middle wall  62  and flat opposite side walls  64 ,  66 . When the covering is pressed down against the base, one of the hat parts fits into the other hat part. In  FIGS. 1-8 , the covering hat part  50  has a downwardly-opening recess  70  that receives the upwardly-projecting base hat part. When the hat parts fit into one another, their side wall lie facewise adjacent to each other. A quantity of adhesive on any of the walls then can bond the walls together. In  FIG. 3  the quantity of adhesive  34  in the form of a self-contained strip has been placed on the hat middle wall  62  of the base. The side walls of the hat parts resist relative horizontal movement of the peripheral portions even without adhesive. The covering has a covering transition portion  72  that extends primarily horizontally and that separates the covering hat part  50  from the tear line  26 . The transition portion  72  has a radial horizontal length at least as great as that of the hat middle walls ( 52 ,  62 ). 
       FIG. 6  though  8  show three steps in the handling of the container by a store clerk. Initially, many bases  12  are shipped in a stack and many coverings  16  are shipped in a separate stack. In  FIG. 6 , all three sides of the base hat part  60  are covered with adhesive.  FIG. 6  shows three strips of activatable adhesive such as  80 ,  82  and  84  which lie on each of the three sides of the base hat  60 . The adhesive is not activated, so its will not yet bond the base hat to the covering hat. A clerk in a food store who is normally wearing plastic gloves, takes a base from its stack and loads goods such as food  50  ( FIG. 6 ) into the base cavity. As shown in  FIG. 7 , the clerk then pushes down the covering  16  onto the base. The clerk makes sure that the peripheral cover portion  22  is well seated on the base. As shown in  FIG. 8 , the clerk then places the container with food therein, in a UV (ultraviolet light) chamber  86 . In the chamber, ultraviolet light  88  is directed onto the adhesive to activate it so the adhesive strongly bonds the peripheral portions of the covering and of the base. The container is now ready for display for sale, and customers can see that the container has not been opened because the tear line has not been ripped. 
       FIG. 3  shows adhesive  34  which has been applied to only the base hat middle wall  62 , although adhesive could be applied to the base hat side walls as in  FIGS. 6-8 .  FIG. 2  shows that the tear line  26  extends on either side of the lift tab  30  to the extreme edge of the covering. The lift tab extends horizontally at least one-quarter inch radially beyond the covering so it can be easily grasped. The peripheral cover portion ends at opposite tear line ends  92 ,  94  which lie in a gap  90 .  FIG. 2  also shows that the hat parts such as the covering hat part  50 , extend around the entire container periphery except for the gap  90  around the lift tab  30 . The adhesive is preferably applied along the entire container periphery except for the gap  90 . The adhesive is preferably in the form of a strip  93  that extends along the entire lengths of the hat parts, although there can be gaps in such strip of adhesive. The adhesive strip should lie at  95  and  97  on opposite sides of the tear gap  90 . It is possible to provide one or more strips of contact adhesive with inner faces that are bonded to one of the hat parts at the container manufacturing factory, and with outer faces that are protected with peel-off strips. In that case, the adhesive is activated (made ready to stick to a surface it contacts) by the clerk peeling off the peel-off strip. However, the strongest bonding is usually obtained by an adhesive that is activated by shining ultraviolet light at the adhesive. The adhesive is preferably applied to the one of the two hat parts with exposed surfaces (that do not lie in a recess) to be bonded to. 
       FIG. 9  shows another container  100  which is modified from the container of  FIG. 3  by the covering hat part  102  projecting downward so all of its lower surfaces are exposed. The base hat part  104  forms an upwardly-opening recess  106  that receives the covering hat part and adhesive strips  107 ,  108 ,  109  on the covering hat part. 
       FIG. 10  shows another container which is similar to that of  FIG. 9 , except that the peripheral covering portion  110  and peripheral base portion  110 ,  112  are formed with a mechanical outer latch device  114  that includes outer latch device parts  120 ,  122 . This is in addition to the lid latch  42 A which has a covering part  44 A and a base latch part  46 A. The outer latch device  114  (in addition to latch  42 A) holds the peripheral covering portion closed firmly on the peripheral base portion, so the orientations of the hat part walls and of the adhesive strips is more closely controlled. This helps assure that adhesive strips  124  will bond to both pairs of adjacent walls of the hat parts as well as the horizontal hat wall. 
       FIG. 11  illustrates another design of hat parts  130 ,  132  on the peripheral parts  134 ,  136  of the covering and the base. The covering hat part  130  forms a recess  140  and forms a pair of tabs  142 ,  144  with free upper ends  146 , that project into the recess. The free upper ends form upwardly-facing shoulders. The base hat part  132  forms a pair of downwardly-facing shoulders  150 ,  152 . When the base hat part is inserted into the recess of the covering hat part as in  FIG. 12 , the downwardly-facing shoulders of the base hat part engage the upwardly-facing shoulders on the tabs, and prevent the peripheral base part  136  from separating from the covering. The top connection parts of the lid and base engage each other in a snap fit. Applicant prefers to provide many pairs of tabs  142 ,  144  along the length of the hats around the container, or one very long pair of tabs. Applicant prefers to taper the heights of the tabs and/or shoulders that engage the tabs. This assures that a long length of tab(s) and shoulders are engaged when the lift tab  30  ( FIG. 1 ) is lifted far enough to begin tearing along the tear line. The tabs and shoulders lie at the locations  95 ,  97  ( FIG. 2 ) on opposite sides of the tear gap  90 . 
     In  FIG. 12 , the lower hat part  132  is the inner hat part, which is received in the upper or outer hat part  130 .  FIG. 12  shows that the deepest projecting end  160  (the upper end in  FIG. 12 ) of the inner hat part  132  rests in the deepest end  162  of the outer hat part, and the deepest ends of the hat parts ( 160 ,  162 ) engage each other. The shallowest interfitting ends  170 ,  172  of the hat parts do not engage each other. Also, the shoulders  150 ,  152  of the inner hat part engage shoulders formed at  146 . This interference fit of hat parts resists separation of the covering  16  from the base  12 . 
     In one example, the container is constructed of two separate sheets of approximately 0.020 inch thick (0.01 to 0.06 inch) transparent plastic, and has a container width of 5 inches and a container length of 8 inches except at the lift tab. 
     In one example, the container is constructed of two separate sheets of 0.020 inch thick transparent plastic, and has a container width of 5 inches and a container length of 8 inches except at the lift tab. 
     Thus, the invention provides a tamper evident container that includes a base and covering with peripheral portions that are readily fixed to one another when a clerk loads food or other goods into the base and closes the covering on the base. In one container, adhesive lies on at least one of the peripheral portions and a clerk easily activates the adhesive as by directing ultraviolet light at it. The covering includes a lid that is joined to the peripheral covering portion by a tear line. When a consumer who has bought the container filled with goods decides to open it, the consumer has to apply a sustained force, such as a force applied along a distance of 7.5 inches for a container of a length of 8 inches, with the container making considerable noise when the tear line is torn. The tear force is large, such as 10 pounds. The lid and base form a latch so that after the container is opened by a customer, it requires the application of a smaller force such as a downward force of 3 pounds applied along a distance such as one-quarter inch, to close the container, and a similar upward force and force-applied distance to reopen the container. The fact that the container makes considerable noise when initially opened after a clerk has initially closed the container, the large initial opening force and force-applied distance, and the fact that the container clearly indicates when it has been opened, makes it unlikely that a customer will secretly open the container and assures customers that the container has not been opened. 
     Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.