Sidewall blank for substantially eliminating twist in deep bottom containers

Abstract

A cup forming sidewall blank includes a piece of flexible sheet material having an upper edge, a lower edge, and a pair of opposite side edges with an area at or adjacent the lower edge of the sidewall blank being provided with relief formations which extend generally upwardly and perpendicularly relative to the lower edge. The relief formations preferably take the form of score lines, slits, notches or other suitable constructions which are generally spaced from one another and are of equal length relative to the sidewall blank lower edge.

What is claimed is: 
     
         1 . In a two piece cup formed by a sidewall member having an upper edge, a lower edge and pair of opposite side edges overlapped and sealed along an overlapped side seam. and a bottom member sealed along the lower edge of the sidewall member, the improvement comprising:
 a plurality of relief formations provided at or adjacent the lower edge of the sidewall member.   
     
     
         2 . The improvement of  claim 1 , wherein the relief formations extend upwardly from the lower edge. 
     
     
         3 . The improvement of  claim 1 , wherein the relief formations extend perpendicularly from the lower edge. 
     
     
         4 . The improvement of  claim 1 , wherein the relief formations are equally spaced from one another. 
     
     
         5 . The improvement of  claim 1 , wherein the relief formations extend continuously along a length of the lower edge. 
     
     
         6 . The improvement of  claim 1 , wherein the relief formations are formed as a series of score lines. 
     
     
         7 . The improvement of  claim 1 , wherein the relief formations are formed as a series of slits. 
     
     
         8 . The improvement of  claim 1 , wherein the relief formations are formed as a series of inverted V-shaped notches. 
     
     
         9 . The improvement of  claim 1 , wherein the relief formations are of equal size. 
     
     
         10 . A two piece cup comprising:
 a sidewall member having an upper edge, a lower edge, a pair of opposite side edges overlapped and sealed together along an overlapping side seam; and   a bottom member sealed along the lower edge of the sidewall member,   wherein a plurality of relief formations are formed at or adjacent the lower edge of the sidewall member such that undesirable wrinkle effects normally incurred during bottom formation of the cup which lead to leaking problems are prevented.   
     
     
         11 . A cup forming sidewall blank comprising:
 a piece of flexible sheet material having an upper edge, a lower edge and pair of opposite side edges wherein the lower edge is provided with a series of spaced apart relief formations extending upwardly therefrom.   
     
     
         12 . The sidewall blank of  claim 11 , wherein the sheet material has a generally trapezoidal shape.