We claim the ornamental design for an ironing board, as shown and described.
FIG. 1 is a perspective view of an ironing board showing the new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is an enlarged view of a portion of the ironing board of FIG. 1 showing the display in use.
The broken line showing the display in FIG. 8 forms no part of the claimed design. All other broken lines shown in the drawings depict portions of the ironing board that form no part of the claimed design. The dashed broken lines in FIG. 8 show the boundary of the enlarged view and forms no part of the claimed design.