The ornamental design for a safetyhelmet, as shown and described.
FIG. 1 is a front, right-side, top perspective view of a safety helmet, showing the new design;
FIG. 2 is a rear, right-side, top perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left-side elevational view thereof;
FIG. 6 is a right-side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The evenly broken lines depict portions of the safety helmet that form no part of the claimed design. The dash-dot broken lines in FIGS. 3 and 8 depict the boundary of the claimed design and form no part of the claimed design.