The ornamental design for a barbellclamp, as shown and described.
FIG. 1 is a front, right, and top perspective view of a barbell clamp, showing my design.
FIG. 2 is a rear, left, and bottom perspective view thereof.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a left side elevation view thereof.
FIG. 6 is a right side elevation view thereof.
FIG. 7 is a top plan view thereof.
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is a partial enlarged view of an area labeled 9 in FIG. 1 comprising an inside of clip.
The broken lines shown in the drawings are included for the purpose of illustrating portions of the barbell clamp that form no part of the claimed design.