The ornamental design for a drivearm for headframe of an adjustablebed, as shown and described.
FIG. 1 is a perspective view of a drive arm for a head frame of an adjustable bed in accordance with the present invention;
FIG. 2 is a top view of the drive arm of FIG. 1;
FIG. 3 is a side view of the drive arm of FIGS. 1 and 2; and,
FIG. 4 is an end view of the drive arm of FIGS. 1-3.
The dash-dash broken lines illustrate environmental subject matter only and the dash-dot-dash broken lines illustrate the boundaries of the claim. All broken lines form no part of the claimed design.