| 摘要 |
Such a construction is adopted that the length of a second parallel link (3) in the longitudinal direction and the length of a weight holding arm (19) in the lateral direction are made extendable or contractible, whereby a counterweight (W4) is moved on a straight line (X) connecting a forward end ( beta 1) of a support arm (9) to a rotatable fulcrum (S), so that, only by moving said counterweight (W4) along the straight line (X), a weight (W1-3) of an operation microscope or the like can be well-balanced by the counterweight (W4) in the both horizontal and vertical directions easily and reliably. |
