Blow molded container with self-supporting base reinforced by hollow ribs

Claim 1

A blow molded plastic container comprising: a hollow tubular body having a side wall of annular shape, and terminating at its lower end in an integral aligned base; said base having a truncated frusto-conical shaped inner wall projecting upwardly into said hollow tubular body, a top wall at the upper end of said inner wall, and an annular downwardly concave chamber extending about said frusto-conical wall, said chamber having an outer wall which merges at its upper end with said tubular side wall and at its lower end with said frusto-conical wall to form a bottom surface, a plurality of radially extending hollow ribs formed in said bottom surface so as to extend upwardly therefrom a small distance so as to intersect said inner and outer walls at a position substantially below said top wall; said bottom surface between said ribs forming a plurality of container support feet each of which is of substantial width in a direction circumferentially of said base relative to said ribs to provide firm support for said container, said ribs being symmetrically arranged relative to the longitudinal axis of said container to provide for a symmetrically uniform support of said cotainer on said feet without tipping of the container.