The ornamental design for a convertiblecrib, as shown and described.
FIG. 1 is a perspective view of a convertible crib showing my new design;
FIG. 2 is a front view of the convertible crib of FIG. 1;
FIG. 3 is a rear view of the convertible crib of FIG. 1;
FIG. 4 is a right side view of the convertible crib of FIG. 1;
FIG. 5 is a left side view of the convertible crib of FIG. 1;
FIG. 6 is a top view of the convertible crib of FIG. 1; and,
FIG. 7 is a bottom view of the convertible crib of FIG. 1.
The broken line showing of a mattress is for illustrating environmental structure and forms no part of the claimed design. The uneven broken line representations in FIGS. 1–7 are for illustrative purposes only and form no part of the claimed design.