The ornamental design for a fourblade de-thatching, mulching and grass cutting lawn mower blade, as shown and described.
FIG. 1 is a top perspective view of a four blade de-thatching, mulching and grass cutting lawn mower blade showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is an enlarged side elevational view thereof;
FIG. 5 is an enlarged cross sectional view taken on line 5-5 of FIG. 2;
FIG. 6 is a reduced perspective view of FIG. 1;
FIG. 7 is another reduced perspective view of FIG. 1;
FIG. 8 is a reduced elevation view of FIG. 4;
FIG. 9 is a reduced elevational view of FIG. 1; and,
FIG. 10 is a reduced top plan view of FIG. 2.
The broken line showing of a lawn mower in FIGS. 6 and 7 and, a lawn mower and grass in FIGS. 8, 9 and 10 are included for the purpose of illustrating environmental structure only and forms no part of the claimed design.