Convertible sofa bed

FIG. 1 is a front, top perspective view of a convertible sofa bed, showing my new design in a first configuration of use;

FIG. 2 is a rear, bottom perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof;

FIG. 9 is a front, top perspective view of the convertible sofa bed, shown in a second configuration of use; and,

FIG. 10 is a front, top perspective view of the convertible sofa bed, shown in a third configuration of use.

The dashed broken lines in the figures are for the purposes of illustrating portions of the convertible sofa bed, which form no part of the claimed design.