The ornamental design for mounting frame, as shown and described.
FIG. 1 is a perspective view of the mounting frame showing my design;
FIG. 2 is a first side view thereof;
FIG. 3 is a second side view thereof, opposite that shown in FIG. 2;
FIG. 4 is another side view thereof, 90 degrees offset from that shown in FIG. 2;
FIG. 5 is another side view thereof, opposite that shown in FIG. 4;
FIG. 6 is a top view of the mounting frame;
FIG. 7 is a bottom view thereof;
FIG. 8 is an exemplary plan view illustrating the mounting frame attached to a base plate of a microscope according to embodiments of the present invention; and,
FIG. 9 is an exemplary plan view illustrating the mounting frame attached to a retinal viewing system on a microscope according to embodiments of the present invention.
The broken lines shown herein are for illustrative purposes only and form no part of the claimed design.