The ornamental design for a blow-molded rib structure for a table, as shown and described.
FIG. 1 is a perspective view of a blow-molded rib structure for a table according to my new design;
FIG. 2 is a perspective view of a lower component of the blow-molded rib structure of FIG. 1, viewed from the same direction as FIG. 1 and enlarged for clarity of illustration; and,
FIG. 3 is a perspective view of the lower component of the blow-molded rib structure of FIG. 1, viewed from a different direction and enlarged for clarity of illustration.
The broken lines showing a table illustrate environment and form no part of the claimed design.