I claim the ornamental design for a hanging device, as shown and described.
FIG. 1 is a perspective view of a hanging device affixed the underside of a table.
FIG. 2 is a second perspective view thereof.
FIG. 3 is a first side elevation view thereof.
FIG. 4 is a second side elevation view thereof.
FIG. 5 is a first end elevation thereof.
FIG. 6 is a second end elevation thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof. The stippling represents an adhesive material.
The broken lines depict an environment of use which forms no part of the claim. The stippling represents an adhesive surface which is part of the claim.