The ornamental design for a capclosingmechanism, as shown and described.
FIG. 1 is a perspective view of a cap closing mechanism;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a right side elevation view thereof, the left side view being a mirror image thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a top plan view thereof.
The broken lines showing a baseball cap depict environmental subject matter that forms no part of the claimed design.
The strings are shown with symbolic breaks in their lengths. The appearance of any portion of the article between the break lines forms no part of the claimed design. The areas adjacent to the solid line angled elements are portions of the cap closing mechanism that form no part of the claimed design.