I claim the ornamental design for a safety bar, as shown and described.
FIG. 1 is a front view of a safety bar in accordance with an embodiment of my invention; the broken lines, which represent a wall to which the safety bar may be attached, are for illustrative purposes only, and form no part of the claimed design;
FIG. 2 is a top view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a bottom view of FIG. 1, showing an alternate position of the safety bar; the broken lines, which represent a wall to which the safety bar may be attached, are for illustrative purposes only, and form no part of the claimed design.