The ornamental design for protective cover accessory for excavator arm, as shown and described.
FIG. 1 is an exploded isometric view of protective cover accessory for excavator arm showing my new design;
FIG. 2 is a front elevational view of FIG. 1;
FIG. 3 is a rear elevational view of FIG. 1;
FIG. 4 is a left elevational view of FIG. 1;
FIG. 5 is a right-side elevational view of FIG. 1;
FIG. 6 is a top plan view of FIG. 1;
FIG. 7 is a bottom plan view of FIG. 1;
FIG. 8 is an operational view of protective cover accessory for excavator arm; and,
FIG. 9 is another operational view of protective cover accessory for excavator arm.
The broken lines are included for the purpose of illustrating features of the protective cover accessory for excavator arm that form no part of the claimed design.