Heavy duty electric plug
FIG. 1 is an enlarged perspective view of a heavy duty electric plug illustrating our new design; 
     FIG. 2 is a front elevational view thereof; 
     FIG. 3 is a rear elevational view thereof; 
     FIG. 4 is a side elevational view thereof; 
     FIG. 5 is an elevational view of the side opposite that shown in FIG. 4; 
     FIG. 6 is a bottom plan view thereof; 
     FIG. 7 is a top plan view thereof; 
     FIG. 8 is an enlarged perspective view of an alternate embodiment of the heavy duty electric plug differing in size and third prong; 
     FIG. 9 is a front elevational view thereof; 
     FIG. 10 is a rear elevational view thereof; 
     FIG. 11 is a side elevational view thereof; 
     FIG. 12 is an elevational view of the side opposite that of FIG. 11; 
     FIG. 13 is a top plan view thereof; and 
     FIG. 14 is a bottom plan view thereof. 
     The surface design shown completely in FIGS. 1 and 8 is incompletely shown in FIGS. 2-5, 7 and 9-13 for ease of illustration and is understood to repeat over the area left blank. 
     The portions of FIG. 1 and FIG. 8 shown in broken lines represent an electric cord and they do not form a part of the claimed design.