The ornamental design for a couplingarticle, as shown and described.
FIG. 1 is a perspective view of the embodiment of a coupling article;
FIG. 2 is a top plan view of FIG. 1;
FIG. 3 is a front elevational view of FIG. 1, the rear elevational view being a mirror image;
FIG. 4 is a right side elevational view of FIG. 1, the left side elevational being a mirror image; and,
FIG. 5 is a bottom plan view of FIG. 1.
The coupling article is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.