The ornamental design for a safety saw, as shown and described.
FIG. 1 is a photograph of the right side of the safety saw having a handle and a serrated file attached to a saw support portion of the saw body;
FIG. 2 is a photograph of the left side of the safety saw having a handle and a serrated file attached to a saw support portion of the saw body;
FIG. 3 is a photograph of the front side of the safety saw;
FIG. 4 is a photograph of the back side of the safety saw;
FIG. 5 is a photograph of the top-end of the safety saw having a serrated file attached to a saw support portion of the safety saw;
FIG. 6 is a photograph of a portion of the right side of the safety saw showing a serrated file attached to a saw support portion of the safety saw; and,
FIG. 7 is a photograph of a portion of the right side of the safety saw showing the serrated file having a serrated outer surface and a plurality of notches.