The ornamental design for a double chaincollarkeeper, as shown and described.
FIG. 1 is a front elevational view of the invention;
FIG. 2 is a top plan view of the invention which is the same as the bottom
plan view;
FIG. 3 is a side elevational view of the invention; and,
FIG. 4 is a partial rear elevational view, with part of the collar keeper
removed for ease of illustration, the portion not shown being a mirror
image.