I claim the ornamental design for a football helmet, as shown and described.
FIG. 1 is a perspective view of a football helmet showing my new design;
FIG. 2 is a right side view of the helmet of FIG. 1;
FIG. 3 is a left side view of the helmet of FIG. 1;
FIG. 4 is a front view of the helmet of FIG. 1;
FIG. 5 is a rear view of the helmet of FIG. 1;
FIG. 6 is a top view of the helmet of FIG. 1; and,
FIG. 7 is a bottom view of the helmet of FIG. 1.
Those portions of the football helmet which are presented in the Figures with dotted lines (“- -”) show unclaimed aspects of the football helmet and as a result, they form no part of the claimed— football helmet. The dot-dash-dot broken lines (“⋅ - ⋅”) in the Figures represent unclaimed boundaries of the Football Helmet. Moreover, any surface shading presented in the accompanying Figures is provided to indicate contours of the football helmet and is not intended to be illustrative of the football helmet's surface finish, texture or gloss.