Blow molded bottle with improved self supporting base

Abstract

An improved beverage bottle support base is disclosed having an upwardly directed conical inner wall, the apex of which is centrally of the base and a convex outer wall of annular shape surrounding the conical inner wall and merging therewith and with the side wall of the bottle. A plurality of reinforcing grooves extend radially outward from the apex and merging with the convex outer wall, dividing the conical inner wall and convex outer wall into a plurality of spaced apart hollow feet.

What is claimed: 
     
       1. A plastic bottle for beverages having a hollow body with a generally cylindrical side wall and a base structure merging with aid side wall, said base structure comprising: an upwardly concave inner wall having upper and lower ends and an apex at the upper end, said apex being substantially centrally of said base structure; a convex outer wall of annular shape surrounding said inner wall and having upper and lower ends, said outer wall merging with the lower end of said inner wall at the lower end of the outer wall and merging with the lower end of said side wall at the upper end of said outer wall; a plurality of upwardly projecting ribs in said base structure extending radially outwardly from said apex to said outer wall, each of said ribs being smoothly continuous over substantially the entire length thereof, said ribs interrupting said base structure inner and outer walls so as to divide said inner wall and said outer wall into a plurality of circumferentially spaced apart hollow feet located below said ribs, said ribs merging with said outer wall at the radially outer ends of the ribs; and   said feet forming beating surfaces at the lowermost points thereof for contact with a supporting surface, said bearing surfaces and said concave inner wall being relatively inclined when viewed in vertical section through said hollow feet so as to form corners directed interiorly of said bottle to stiffen said feet and resist deformation of said base structure.   
     
     
       2. The bottle of claim 1 wherein said ribs increase in width in a direction radially outwardly of said base structure. 
     
     
       3. The bottle of claim 1 wherein said plurality of ribs are three in number. 
     
     
       4. The bottle of claim 1 further comprising hollow stiffening projections formed on and projecting upwardly from said ribs. 
     
     
       5. The bottle of claim 4 wherein said upward projections are of substantially inverted U-shape. 
     
     
       6. The bottle of claim 4 wherein said upward projections are of progressively increasing width in a direction radially outwardly of said base structure. 
     
     
       7. The bottle of claim 1 wherein said bearing surfaces are formed by circular arc portions at the merger of said convex outer wail and said inner wall as viewed in vertical section through said hollow feet. 
     
     
       8. A plastic bottle for beverages having a hollow body with a generally cylindrical side wail and a base structure merging with said side wall, said base structure comprising: an upwardly conical inner wall having upper and lower ends and an apex at the upper end, said apex being substantially centrally or said base structure;   a convex outer wall of annular shape surrounding said conical inner wall and having upper and lower ends, said outer wall merging with the lower end of said inner wall st the lower end of the outer wall and merging with the lower end of said side wall at the upper end of said outer wall;   an annular circular arc portion merging said conical inner wall with said convex outer wall defining a bearing surface, said conical inner wall and said circular arc portion being relatively inclined when viewed in vertical section through said bottle so as to form corners directed interiorly of said bottle adjacent the juncture of said inner wall and said circular arc portions to stiffen said .[.feet.]. .Iadd.inner wall .Iaddend.and said arc portions;   three ribs upwardly projecting in said base structure extending radially outward from said apex, said ribs interrupting said base structure inner and outer walls so as to divide said conical inner wall and said convex outer wail into a plurality of spaced apart hollow feet located below said ribs, said ribs merging with said outer wall at the radially outer ends of the ribs; and   hollow projections extending upward from said ribs, said upward projections increasing in width in a direction radially outwardly or said ribs from said apex. .Iadd.9. A plastic bottle having a hollow body with a generally cylindrical side wall and a base structure merging with said side wall, said base structure comprising:   an upwardly concave inner wall having a centrally located apex and extending downwardly and radially outwardly from said apex to an annular lower end;   a convex outer wall of annular shape surrounding said inner wall, said outer wall having an upper end merging with said side wall and extending downwardly and inwardly to an annular lower end;   an intermediate wall connecting the lower end of said inner wall with the lower end of said outer wall and including a bearing surface at the lower most point of said base structure for contact with a supporting surface, said intermediate wall and said concave inner wall being inclined relative to each other .Iadd.at said bearing surface and .Iaddend.adjacent said lower end of said inner wall.Iadd., .Iaddend.when viewed in vertical section.Iadd., .Iaddend.so as to form a corner directed interiorly of said bottle .Iadd.directly above said bearing surface .Iaddend.to stiffen and resist deformation of said base structure; and   a plurality of radially outwardly extending ribs in said base structure, said ribs projecting upwardly and interrupting said intermediate wall and at least a portion of said outer wall so as to form in said base structure a plurality of circumferentially spaced apart hollow feet located below said ribs, said ribs being smoothly continuous over substantially the entire lengths thereof and merging with said outer wall at the radially outer ends of said ribs.  .Iadd.10. The bottle of claim 9 wherein said intermediate wall is a circular arc when viewed in vertical cross section. .Iaddend. .Iadd.11. The bottle of claim 9 wherein said ribs extend radially inwardly into said inner wall interrupting at least a portion of said inner wall. .Iaddend.