Door Knob

FIG. 1 is a front view of a door knob; FIG. 2 is a right side view thereof; FIG. 3 is a left side view thereof; FIG. 4 is a rear view thereof; FIG. 5 is a top view thereof; FIG. 6 is a bottom view thereof; FIG. 7 is a perspective view thereof; and, FIG. 8 is a partial enlarged view thereof based on section 8 - 8 in FIG. 7 . The broken lines in the drawings depict portions of the door knob that form no part of the claimed design.