The ornamental design for an accessory for a robotarm, as shown and described.
FIG. 1 is an upper perspective view of the accessory for a robot arm showing my design.
FIG. 2 is a side view thereof;
FIG. 3 is an opposite side view thereof;
FIG. 4 a bottom plan view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is an end elevation view thereof;
FIG. 7 is an opposite end elevation view thereof; and,
FIG. 8 is another perspective view thereof, showing attachment to an accessory in broken lines.
The robot arm is a surgical device, and the accessory can be a surgical tool. The portions shown in broken lines are for illustrative purposes only and form no part of the claimed design.