FIG. 1 is a perspective view of the retractable wheel base in accordance with a first, retracted configuration of the present invention;
FIG. 2 is a rear, bottom perspective view of the retractable wheel base of FIG. 1;
FIG. 3 is a rear elevational view of the retractable wheel base of FIG. 1;
FIG. 4 is a front elevational view of the retractable wheel base of FIG. 1;
FIG. 5 is a right-side elevational view of the retractable wheel base of FIG. 1;
FIG. 6 is a left-side elevational view of the retractable wheel base of FIG. 1;
FIG. 7 is a bottom plan view of the retractable wheel base of FIG. 1;
FIG. 8 is a top plan view of the retractable wheel base of FIG. 1;
FIG. 9 is an alternate perspective view of the retractable wheel base in accordance with a second, expanded configuration of the present invention;
FIG. 10 is a rear, bottom perspective view of the retractable wheel base of FIG. 9;
FIG. 11 is a rear elevational view of the retractable wheel base of FIG. 9;
FIG. 12 is a front elevational view of the retractable wheel base of FIG. 9;
FIG. 13 is a right elevational view of the retractable wheel base of FIG. 9;
FIG. 14 is a left elevational view of the retractable wheel base of FIG. 9;
FIG. 15 is a bottom plan view of the retractable wheel base of FIG. 9; and,
FIG. 16 is a top plan view of the retractable wheel base of FIG. 9.
The broken lines depict portions of the retractable wheel base that form no part of the claimed design.