The ornamental design for a handlebar for an exercisemachine, as shown and described.
FIG. 1 is a perspective view of a handlebar for an exercise machine showing our new design.
FIG. 2 is a side view thereof.
FIG. 3 is an opposite side view thereof.
FIG. 4 is a front view thereof.
FIG. 5 is a rear view thereof.
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
In the drawings, the evenly-spaced broken lines illustrate portions of the handlebar for an exercise machine that form no part of the claim; the dash-dot-dash lines represent boundaries of the claimed design and form no part thereof.