Structures for providing a removable closure

Abstract

A membrane lid with a surface with a substantially triangular-shaped perimeter. The perimeter includes first, second and third corner portions, wherein each corner portion is bisected by an imaginary line. The membrane lid further includes a projection with a tab and adapted to initially direct a lifting force to at least one of the corner portions. The projection either extends outwardly from the perimeter such that the projection is non-symmetrically disposed with respect to the imaginary line of any adjacent corner portion, or the projection extends non-continuously from an adjacent corner portion and is substantially symmetrically disposed with respect to the imaginary line of the adjacent corner portion. Containers are also provided with a lip having a substantially triangular-shaped horizontal cross-section. The lip includes three corner portions and three sides, wherein the sides of the lip are structured differently than the corner portions of the lip to increase the relative rigidity of the sides with respect to the corner portions such that the corner portions and the sides are adapted to exhibit a substantially uniform reaction pressure when applying a membrane lid to the lip of the container.

What is claimed is:  
     
         1 . A membrane lid comprising: 
 a) a surface including a substantially triangular-shaped perimeter with first, second and third corner portions, wherein each corner portion is bisected by an imaginary line; and    b) a projection including a tab and adapted to initially direct a lifting force to at least one of the corner portions, wherein the projection either extends outwardly from the perimeter such that the projection is non-symmetrically disposed with respect to the imaginary line of any adjacent corner portion, or the projection extends non-continuously from an adjacent corner portion and is substantially symmetrically disposed with respect to the imaginary line of the adjacent corner portion.    
     
     
         2 . The membrane lid of  claim 1 , wherein the projection extends outwardly from the perimeter such that the projection is non-symmetrically disposed with respect to the imaginary line of any adjacent corner portion.  
     
     
         3 . The membrane lid of  claim 2 , wherein the projection includes a lifting point and a lifting area, the lifting area being defined by a first imaginary line extending from the lifting point to an outer tangential point of the first corner portion and a second imaginary line extending from the lifting point to an outer tangential point of the second corner portion, and wherein the projection substantially covers the lifting area.  
     
     
         4 . The membrane lid of  claim 2 , wherein the projection includes first and second lifting points and first and second lifting areas, the first lifting area being defined by a first outer imaginary line extending from the first lifting point to an outer tangential point of the first corner portion and a first inner imaginary line extending from the first lifting point to an outer tangential point of the second corner portion, and the second lifting area being defined by a second outer imaginary line extending from the second lifting point to an outer tangential point of the second corner portion and a second inner imaginary line extending from the second lifting point to an outer tangential point of the first corner portion, and wherein the projection substantially covers the first and second lifting areas.  
     
     
         5 . The membrane lid of  claim 2 , wherein the projection extends non-continuously from the perimeter.  
     
     
         6 . The membrane lid of  claim 1 , wherein the projection extends non-continuously from an adjacent corner portion and is substantially symmetrically disposed with respect to the imaginary line of the adjacent corner portion.  
     
     
         7 . The membrane lid of  claim 6 , wherein the projection comprises a weakened area.  
     
     
         8 . The membrane lid of  claim 7 , wherein the weakened area includes portions of the projection that define an aperture.  
     
     
         9 . The membrane lid of  claim 8 , wherein the aperture has an open perimeter.  
     
     
         10 . The membrane lid of  claim 9 , wherein the projection defines a slit in communication with the aperture to provide the open perimeter.  
     
     
         11 . The membrane lid of  claim 8 , wherein the aperture has a closed perimeter.  
     
     
         12 . The membrane lid of  claim 8 , wherein the aperture is bisected by one of the imaginary lines.  
     
     
         13 . The membrane lid of  claim 7 , wherein the weakened area includes a scored portion of the projection.  
     
     
         14 . The membrane lid of  claim 13 , wherein the projection is scored by perforating the projection.  
     
     
         15 . The membrane lid of  claim 13 , wherein the projection is scored by cutting the projection.  
     
     
         16 . The membrane lid of  claim 15 , wherein the cut extends only partially through the thickness of the projection.  
     
     
         17 . The membrane lid of  claim 15 , wherein the cut extends entirely through the thickness of the projection.  
     
     
         18 . The membrane lid of  claim 13 , wherein the projection is scored by crimping the projection.  
     
     
         19 . The membrane lid of  claim 1 , wherein the perimeter has a substantially equilateral triangular shape.  
     
     
         20 . The membrane lid of  claim 1 , formed of at least one layer of foil and at least one polymer layer.  
     
     
         21 . The membrane lid of  claim 1 , formed from a multi-layer laminate comprising an acrylic primer, a foil layer, and an ethyl vinyl acetate sealant layer.  
     
     
         22 . The membrane lid of  claim 1 , further comprising a bevel portion.  
     
     
         23 . The membrane lid of  claim 1 , wherein the projection is interrupted along the imaginary line of an adjacent corner portion.  
     
     
         24 . The membrane lid of  claim 1 , wherein the projection extends outwardly from the perimeter without intersecting the imaginary line of any adjacent corner portion.  
     
     
         25 . The membrane lid of  claim 1 , wherein the tab comprises a plurality of tabs.  
     
     
         26 . The membrane lid of  claim 1 , wherein the projection comprises a plurality of projections.  
     
     
         27 . A container comprising a lip having a substantially triangular-shaped horizontal cross-section, the lip including three corner portions and three sides, wherein the sides of the lip are structured differently than the corner portions of the lip to increase the relative rigidity of the sides with respect to the corner portions such that the corner portions and the sides are adapted to exhibit a substantially uniform reaction pressure when applying a membrane lid to the lip of the container.  
     
     
         28 . The container of  claim 27 , wherein the lip comprises a top surface, an outer wall surface and a bottom surface, and the corner portions of the lip having an outwardly protruding substantially U-shaped outer wall surface.  
     
     
         29 . The container of  claim 27 , wherein the sides of the lip have an outwardly protruding substantially U-shaped outer wall surface.  
     
     
         30 . The container of  claim 27 , wherein the sides of the lip have an outwardly protruding substantially W-shaped outer wall surface.  
     
     
         31 . The container of  claim 27 , wherein the sides of the lip have a substantially flat outer wall surface.  
     
     
         32 . The container of  claim 27 , wherein a horizontal thickness of the lip is substantially the same at the corner portions and at the sides.  
     
     
         33 . The container of  claim 27 , wherein a horizontal thickness of the lip is substantially greater at the sides than at the corner portions.  
     
     
         34 . The container of  claim 27 , wherein the lip comprises a top surface and an outer wall surface, wherein the top surface extends from the top of the outer wall surface at an upward angle with respect to the horizontal.  
     
     
         35 . The container of  claim 27 , further comprising a membrane lid comprising: 
 a) a surface including a substantially triangular-shaped perimeter with first, second and third corner portions, wherein each corner portion is bisected by an imaginary line; and    b) a projection including a tab and adapted to initially direct a lifting force to at least one of the corner portions, wherein the projection either extends outwardly from the perimeter such that the projection is non-symmetrically disposed with respect to the imaginary line of any adjacent corner portion, or the projection extends non-continuously from an adjacent corner portion and is substantially symmetrically disposed with respect to the imaginary line of the adjacent corner portion.