| 摘要 |
A device having an arm which is pivotable around a first axle in a first plane of motion and is counterbalanced by means of a counterweight and wherein the first plane of motion is pivotable around a second axle which is perpendicular to the first axle. In order to permit the use of only one counterweight the counterweight is so coupled to the arm that, on pivoting of the arm, it moves along a straight line located in the first plane of motion, the counterweight and the center of gravity of the arm being on different sides of the second axle. |
