The ornamental design for a coupler mounted bracket, as shown and described.
FIG. 1 is a perspective view of our coupler mounted bracket design;
FIG. 2 is a rear elevation view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines immediately adjacent the shaded areas represent the bounds of the claim and all other broken lines represent unclaimed portions on the design. None of the broken lines form a part of the claimed design.