Collapsible chair base

FIG. 1 is a front perspective view of a collapsible chair base showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is an enlarged view of the portion of FIG. 1 outlined by the dot-dash broken line;

FIG. 9 is a front perspective view of the collapsible chair base assembled with a fabric cover;

FIG. 10 is a front elevational view thereof;

FIG. 11 is a left side elevational view thereof; and,

FIG. 12 is a bottom plan view thereof.

The broken lines shown in the drawings illustrate portions of the article that form no part of the claimed design.

The dash-dot-dash broken lines in FIGS. 1 and 8 are for the purpose of illustrating the enlarged view indicators and form no part of the claimed design.