| 摘要 |
PCT No. PCT/SE86/00246 Sec. 371 Date Jan. 29, 1987 Sec. 102(e) Date Jan. 29, 1987 PCT Filed May 28, 1986 PCT Pub. No. WO86/06950 PCT Pub. Date Dec. 4, 1986.A counter-weight balanced X-ray frame (1) has a vertical column (2) on which a pendulum arm (3) carrying X-ray equipment (4, 5) is mounted for vertical movement therealong and rotational movement therearound. A brake disc (10) for arresting rotational movement and actuated by a magnetic brake (11) is incorporated in a centering mechanism adapted to seek one or more pre-determined positions for the pendulum arm, e.g. when it forms an angle with the frame of 0 DEG , 90 DEG , 180 DEG or 270 DEG , without the operator needing to interfere in the sequence of movements. When the relevant setting position is approached, the operator need only carry out the operating movement which activates corresponding brake means-for example releases a corresponding operating handle on the pendulum arm-whereupon the pendulum arm itself adopts the pre-determined setting position. |
