Reclosable plastic container with readily apparent tamper evident feature

Abstract

A container includes a lid and base having flanges that are initially attached to each other by engagement of attachment regions of fixed and frangible engagement mechanisms provided in the flanges. Each of the frangible engagement mechanisms is frangibly detachable from its flange, and includes at least one wing extending from its attachment region. During a first opening of the container, the attachment regions initially remain fixed together, while the wings are bent at an oblique angle from the plane of the flanges. Upon reclosure of the container, the wings remain obliquely bent, and provide a readily apparent tamper indication. Wing hinges can be included between the wings and attachment regions to enhance the wing bending during initial opening. The lid and base can be separate, or can be attached to each other by a hinge, such as a living hinge or a scored hinge.

I claim: 
     
         1 . A container comprising:
 a base surrounded by a base rim;   a base flange extending outward from the base rim;   a lid surrounded by a lid rim, the lid being attachable to the base so as to close the container;   a lid flange extending outward from the lid rim, the lid flange being configured to lie flat against the base flange when the container is closed;   a fixed engagement mechanism formed in a first flange that is either the lid flange or the base flange, the fixed engagement mechanism including a first attachment region; and   a frangible engagement mechanism formed in a second flange that is the other of the lid flange and the base flange, the frangible engagement mechanism comprising:
 a second attachment region configured for secure attachment to the first attachment region when the container is closed; 
 a wing extending from and attached to the second attachment region; and 
 a frangible boundary at least partially surrounding the second attachment region and the wing, such that the frangible engagement mechanism is frangibly detachable from the second flange; 
   the fixed and frangible engagement mechanisms being separate from and independent of any pull tabs that are included in the lid and base flanges;   the fixed and frangible engagement mechanisms being configured such that:
 upon a first closure of the container the first and second attachment regions are securely attached to each other, the wing being attached to the second flange while lying flat against the first flange; 
 upon completion of a first opening of the container after said first closure, the frangible boundary is broken free of the second flange, such that the frangible engagement mechanism is detached from the second flange and remains securely attached to the fixed engagement mechanism, an orifice being thereby formed in the second flange; and 
 during said first opening of the container, the frangible boundary is severed first in a region proximate the second attachment region before it is severed in a region proximate the wing, thereby causing the wing to be bent at an oblique angle from a plane of the first flange before the frangible engagement mechanism is fully detached from the second flange; and 
 upon a second closing of the container after said first opening, the wing passes through the orifice in the second flange and extends upward at the oblique angle from a plane of the second flange. 
   
     
     
         2 . The container of  claim 1 , wherein the frangible engagement mechanism further includes at least one wing hinge located between the second attachment region and the wing. 
     
     
         3 . The container of  claim 1 , wherein the wing hinge is a living hinge. 
     
     
         4 . The container of  claim 3 , wherein the wing hinge includes at least one U-shaped portion. 
     
     
         5 . The container of  claim 3 , wherein the wing hinge includes at least one V-shaped portion. 
     
     
         6 . The container of  claim 3 , wherein the wing hinge includes at least one semi-circular portion. 
     
     
         7 . The container of  claim 1 , wherein before said first opening the frangible boundary is attached by a perforated attachment to the second flange. 
     
     
         8 . The container of  claim 1 , wherein the frangible boundary completely surrounds the frangible engagement mechanism. 
     
     
         9 . The container of  claim 1 , wherein the frangible boundary only partially surrounds the frangible engagement mechanism, while a remaining boundary of the frangible engagement mechanism extends to an edge of the second flange and is not attached to the second flange. 
     
     
         10 . The container of  claim 1 , wherein the container is a plastic container. 
     
     
         11 . The container of  claim 1 , wherein the lid is attached to the base by a container hinge along a hinged side of the container. 
     
     
         12 . The container of  claim 11 , wherein the container hinge is a living hinge. 
     
     
         13 . The container of  claim 11 , wherein the container hinge is a scored hinge. 
     
     
         14 . The container of  claim 11 , wherein the first and second flanges in which the fixed and frangible engagement mechanisms are formed extend from a side of the container that is opposite to the hinged side of the container. 
     
     
         15 . The container of  claim 1 , further comprising a pull tab configured to facilitate opening of the container, the pull tab being separate from and independent of the fixed and frangible engagement mechanisms. 
     
     
         16 . The container of  claim 1 , wherein when the container is closed after the first opening thereof, the lid is attached to the base by a secondary attachment mechanism that is independent of the fixed and frangible engagement mechanisms. 
     
     
         17 . The container of  claim 1 , wherein the secure attachment of the first and second attachment regions includes an interference fit between the first and second attachment regions. 
     
     
         18 . The container of  claim 1 , wherein the secure attachment of the first and second engagement regions includes spot welding of the first attachment region to the second attachment region.