| 摘要 |
Arm element (10) comprising: - a first and a second, substantially parallel upright (20, 30); - a driving rod (40) having ends (43) hinged to the first and the second upright (20, 30); - a first and a second connection element (50, 60) which extend substantially parallel to the driving rod (40) and which are coupled to the first upright (20) and the second upright (30); - a controllable-length linear actuator (70) coupled between one of the uprights (20, 30) and the other upright (20, 30) or the driving rod (40); the first and second connecting elements (50, 60) being provided with counterbalancing means (55, 57, 65, 67) such that, when one of the connecting elements (50, 60) is kept under tension under the effect of the actuator (70), the other of the connecting elements (50, 60) is counterbalanced. |
