Container side wall with ribs causing a predefined varying thickness

Abstract

A container with an improved container side wall is disclosed. The improved container side wall including a top end and a bottom end, an open top and a bottom wall. The top of the container merges with the top end of the side wall and the bottom wall merges with and closes the bottom end of the side wall. The side wall also includes a plurality of ribs which protrude radially outward from an inside surface of the side wall and which are integrally displaced upon the inside surface of the side wall. These ribs cause the inside surface of the container side wall to form a varying thickness. In this manner, an improved container side wall is provided that increases the resistance of the side wall to deformation caused by internal/external positive or negative pressures without significantly increasing the overall amount of material needed to manufacturer the container. The container side wall may assume a cylindrical, rectangle, oval, or square geometry.

What is claimed is:  
     
         1 . A plastic container comprising: 
 a side wall;    an open top formed at a top end of the side wall;    a bottom wall merging with a bottom end of the side wall and closing the bottom end of the side wall; and    a plurality of ribs which protrude radially outward from an inside surface of the side wall and which are integrally displaced upon the inside surface of the side wall, where the ribs cause the side wall to form a varying thickness.    
     
     
         2 . A plastic container comprising: 
 a side wall, where an inside surface of the side wall is of a predefined varying topography; and    a bottom wall merging with a bottom end of the side wall and closing the bottom end of the side wall.    
     
     
         3 . A plastic container comprising: 
 a side wall, where an inside surface of the side wall is of a varying topography and arranged in a predefined pattern; and    a bottom wall merging with a bottom end of the side wall and closing the bottom end of the side wall.    
     
     
         4 . The plastic container according to  claim 3 , wherein the side wall further comprises a plurality of ribs causing the side wall to form the varying thickness.  
     
     
         5 . A preform for blow molded containers comprising: 
 a side wall, where an inside surface of the side wall is of a predefined varying topography;    an open top formed at a top end of the side wall; and    a bottom wall merging with a bottom end of the side wall and closing the bottom end of the side wall.    
     
     
         6 . The preform according to  claim 5 , wherein the side wall further comprises a plurality of ribs providing the side wall with the predefined varying thickness.  
     
     
         7 . A mold for use in an injection molding machine, comprising: 
 a first half and a second half of a mold shell, the first half and the second half cooperating to form a cavity therebetween, the cavity defining an exterior side wall and bottom wall, the cavity further including an aperture being capable of receiving molten plastic;    a core for cooperating with the mold shell and for defining an interior side wall and bottom wall; and    a plurality of channels formed upon the side wall of the core, where the channels are used to mold the molten plastic to form a preform side wall having a predefined varying thickness.    
     
     
         8 . The mold according to  claim 7 , wherein the channels vary in depth generally between 5% and 50% of the greatest distance between the core and the mold shell.  
     
     
         9 . A method for producing a hollow-structured injection molded plastic container, comprising: 
 injection molding a preform comprised of a side wall with a closed bottom end, where an inside surface of the side wall is of a predefined varying topography;    cooling the preform to a predetermined temperature;    stretching the preform to a desired length; and    blow molding the preform to a desired shape, where the side wall maintains a varying thickness.    
     
     
         10 . The method as recited in  claim 9 , wherein the preform further comprises a plurality of ribs providing the side wall with the varying thickness.  
     
     
         11 . The method as recited in  claim 9 , wherein cooling the preform comprises liquid cooling the preform to the predetermined temperature.  
     
     
         12 . The method as recited in  claim 9 , wherein cooling the preform comprises air cooling the preform to the predetermined temperature.  
     
     
         13 . A method for producing a hollow-structured injection molded plastic container, comprising: 
 injection molding a preform comprised of a side wall and a closed bottom end, where the side wall is of a predefined varying thickness;    heating the preform to a desired temperature;    stretching the preform to a desired length; and    blow molding the preform to a desired shape, where the side wall maintains a varying thickness.    
     
     
         14 . The method as recited in  claim 13 , wherein the preform side wall further comprises a plurality of ribs providing the side wall with the varying thickness.  
     
     
         15 . The method as recited in  claim 13 , wherein heating the preform comprises electrically heating the preform to the desired temperature.  
     
     
         16 . The method as recited in  claim 13 , wherein heating the preform comprises heating the preform to the desired temperature with hot air.  
     
     
         17 . A plastic container comprising: 
 a side wall, the side wall being comprised of a plurality of ribs, which protrude radially outward from an inside surface of the side wall, the ribs causing the side wall to have a predefined varying thickness; and    a bottom wall merging with a bottom end of the side wall and closing the bottom end of the side wall.    
     
     
         18 . The plastic container according to  claim 17 , wherein the side wall is cylindrical.  
     
     
         19 . The plastic container according to  claim 17 , wherein the side wall is rectangular.  
     
     
         20 . The plastic container according to  claim 17 , wherein the ribs are uniformly spaced on the inside surface of the side wall.  
     
     
         21 . The plastic container according to  claim 17 , wherein the ribs lie in a plurality of spaced, generally horizontal planes.  
     
     
         22 . The plastic container according to  claim 21 , wherein the ribs extend so as to form a continuous protrusion on the inside surface of the side wall.  
     
     
         23 . The plastic container according to  claim 21 , wherein the ribs extend so as to form a non-continuous protrusion on the inside surface of the side wall.  
     
     
         24 . The plastic container according to  claim 17 , wherein the ribs lie in a plurality of spaced, generally vertical planes.  
     
     
         25 . The plastic container according to  claim 17 , wherein the ribs lie in a plurality of spaced planes that are angled with respect to the horizontal.  
     
     
         26 . A plastic container comprising: 
 a side wall, the side wall being comprised of a plurality of ribs, which protrude radially outward from an inside surface of the side wall, and a plurality of intermediate side wall sections interleaved between the ribs, the combination of the ribs and the intermediate side wall sections causing the side wall to form a predefined varying thickness; and    a bottom wall merging with a bottom end of the side wall and closing the bottom end of the side wall.    
     
     
         27 . The plastic container according to  claim 26 , wherein the ribs will have a thickness generally between 20% and 150% greater than the thickness of the intermediate side wall sections.  
     
     
         28 . A mold for use in an injection molding machine, comprising: 
 a mold shell; and    a core, wherein the mold shell and the core cooperate to form ribs having a predefined pattern on a side wall of a preform and wherein the mold shell and the core have a cooperating diameter and length ratio such that the ribs do not generate a point of interference that prevents the preform from being removed from the mold.