Plastic container having base with annular wall and method of making the same

Abstract

A plastic bottle comprises a base having a chime, a dome and an annular wall extending between the chime and the dome. The annular wall extends generally parallel to a longitudinal axis of the bottle to support the dome against inverting due to internal pressure and increases the bi-axial stretching of the base during blow molding to strengthen the material of the same.

I claim:  
     
         1 . A plastic bottle comprising: 
 a chime;    a dome; and    a wall extending between said chime and said dome.    
     
     
         2 . The plastic bottle of    claim 1    defining a longitudinal axis and said wall being generally parallel to said longitudinal axis.  
     
     
         3 . The plastic bottle of    claim 2    wherein said wall is substantially straight.  
     
     
         4 . The plastic bottle of    claim 3    wherein said bottle is constructed by blow molding a polyethylene terephthalate preform.  
     
     
         5 . The plastic bottle of    claim 4    wherein said preform is constructed by injection molding.  
     
     
         6 . The plastic bottle of    claim 3    wherein said wall forms an angle of between zero and twelve degrees with said longitudinal axis.  
     
     
         7 . The plastic bottle of    claim 6    wherein said angle is approximately six degrees.  
     
     
         8 . The plastic bottle of    claim 1    defining a longitudinal axis and further comprising a substantially straight outer wall extending integrally from said chime substantially parallel to said longitudinal axis.  
     
     
         9 . The plastic bottle of    claim 8    wherein said chime defines a radius of curvature of approximately 0.276 inches.  
     
     
         10 . The plastic bottle of    claim 1    wherein said base defines a substantially annular outer perimeter free from intrusion into the annular shape thereof.  
     
     
         11 . The plastic bottle of    claim 1    defining a longitudinal axis and said wall defining a substantially unobstructed frustoconical ring about said longitudinal axis.  
     
     
         12 . A plastic container comprising: 
 a body portion;    a neck portion extending from a first side of said body portion; and    a base portion extending from and closing a second side of said body portion wherein said base portion comprises;    a wall having a first end and a second end opposite said first end;    a chime extending from a position adjacent to said first end of said wall; and    a dome extending from a position adjacent to said second end of said wall.    
     
     
         13 . The plastic container of    claim 12    defining a longitudinal axis and said wall being generally parallel to said longitudinal axis.  
     
     
         14 . The plastic container of    claim 13    wherein said wall extends substantially straight between said first end thereof and said second end thereof.  
     
     
         15 . The plastic container of    claim 14    wherein said wall forms an angle of between zero and twelve degrees with said longitudinal axis.  
     
     
         16 . The plastic container of    claim 15    wherein said angle is approximately six degrees.  
     
     
         17 . The plastic container of    claim 14    wherein said bottle is constructed of blow molded polyethylene terephthalate.  
     
     
         18 . The plastic container of    claim 12    defining a longitudinal axis and further comprising a substantially straight outer wall extending integrally from said chime substantially parallel to said longitudinal axis.  
     
     
         19 . The plastic container of    claim 18    wherein said chime defines a radius of curvature of approximately 0.276 inches.  
     
     
         20 . The plastic container of    claim 18    wherein said wall defines a substantially unobstructed frustoconical ring about said longitudinal axis.  
     
     
         21 . The plastic container of    claim 12    wherein said chime comprises a lowermost portion of said plastic container upon which said container may rest and said lowermost portion defines a substantially unobstructed ring circumscribing a longitudinal axis defined by said container.  
     
     
         22 . The plastic container of    claim 21    wherein said substantially unobstructed ring lies substantially within a single plane.  
     
     
         23 . A method of making a plastic container comprising the step of blow molding said plastic container from a preform to comprise: 
 a chime;    a dome; and    a wall extending from a position adjacent to said chime to a position adjacent to said dome.    
     
     
         24 . The method of    claim 23    wherein the method of molding said wall comprises the step of forming said wall to be a substantially unobstructed frustoconical ring about a longitudinal axis defined by said container.  
     
     
         25 . The method of    claim 23    wherein said container is formed to define a longitudinal axis and said wall is formed generally parallel to said longitudinal axis.  
     
     
         26 . The method of    claim 25    wherein said wall is formed at an angle of between zero and twelve degrees to said longitudinal axis.  
     
     
         27 . The method of    claim 26    wherein said wall is formed at an angle of approximately six degrees to said longitudinal axis.