The ornamental design for a loaddetector for bed, as shown and described.
FIG. 1 is a front, top and right-side perspective view of a load detector for bed showing our new design;
FIG. 2 is a rear, top and left-side perspective view thereof;
FIG. 3 is bottom perspective view thereof;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a right side elevational view thereof, the left-side elevational view is a mirror image;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The evenly spaced broken lines depict portions of the load detector for bed in which the design is embodied that form no part of the claimed design. The dot-dash chain broken lines define the boundary of the claimed design and form no part of the claimed design.