Tamper evident thermoformed containers

Abstract

A container comprises a tray body having a top lid portion and a bottom portion. The top lid portion and bottom portion form a re-closable seal around their periphery. A top tab extends from the top lid portion. A bottom tab extends from the bottom portion. A locking mechanism is formed in the top and bottom tabs for substantially permanent engagement. A perforation line in at least one of the top and bottom tabs isolates the locking mechanism, whereby the perforation line must be broken when gaining access inside the tray body.

1 . A container comprising: 
 a tray body having a top lid portion and a bottom portion, the top lid portion and bottom portion forming a re-closable seal around their periphery;    a top tab extending from the top lid portion;    a bottom tab extending from the bottom portion;    a locking mechanism formed in the top and bottom tabs for substantially permanent engagement; and    a perforation line in at least one of the top and bottom tabs for isolating the locking mechanism, whereby the perforation line must be broken when gaining access inside the tray body.    
   
   
       2 . The container of  claim 1  wherein the tray body further includes a hinge joining the top lid portion and the bottom portion.  
   
   
       3 . The container of  claim 1  wherein the locking mechanism comprises: 
 a male lock part in one of the top or bottom tabs; and    a female lock part in the other one of the top or bottom tabs;    wherein the male lock part undergoes compression during insertion into the female lock part and subsequently expands after being inserted into the female lock part.    
   
   
       4 . The container of  claim 1  wherein the top and bottom tabs are heat-staked together.  
   
   
       5 . The container of  claim 1  wherein the perforation line comprises a weakening of a selected one of the top or bottom tabs.  
   
   
       6 . The container of  claim 5  wherein the top or bottom tab other than the selected one lacks a perforation line.  
   
   
       7 . The container of  claim 5  wherein the weakening comprises a series of aligned cuts in the selected tab.  
   
   
       8 . The container of  claim 7  wherein the aligned cuts penetrate completely through the selected tab.  
   
   
       9 . The container of  claim 5  wherein the weakening comprises an indentation into the selected tab.  
   
   
       10 . The container of  claim 5  wherein the selected tab includes an isolated section and a grasping section separated by the perforation line, wherein the locking mechanism is formed at the isolated section.  
   
   
       11 . The container of  claim 10  wherein the selected tab is shaped to provide a cut-out creating a lead-in to the perforation line.  
   
   
       12 . The container of  claim 10  wherein the tab other than the selected tab includes a grasping section.  
   
   
       13 . The container of  claim 1  wherein the re-closable seal comprises: 
 a first flange around a periphery of the top lid portion; and    a second flange around a periphery of the bottom portion, wherein the first and second flanges sealingly mate when the locking mechanism is engaged.    
   
   
       14 . The container of  claim 13  wherein the first and second flanges provide an inside-fit lid.  
   
   
       15 . The container of  claim 14  wherein the bottom portion further comprises a raised guard rib around at least a portion of the periphery of the bottom portion for receiving an edge of the top lid portion.  
   
   
       16 . A method for providing tamper evidence of a container having a tray body with a top lid portion and a bottom portion, the top lid portion and bottom portion forming a re-closable seal around their periphery, the top lid portion having a top tab and the bottom portion having a bottom tab, the method comprising the steps of: 
 filling the tray body with desired contents;    closing the container to mate the re-closable seal;    locking the top and bottom tabs for substantially permanent engagement at a locking position on the top and bottom tabs such that the locking position is isolated from the top lid portion and the bottom portion by a perforation line so that the perforation line must be broken when gaining access inside the tray body.