| 摘要 |
<p>Rotation of a body about an axis (82) is achieved by moving an arm (81) extending from the body. The mechanism for moving the arm includes a hydraulic ram having a ram cylinder (84), which is connected to the arm (81), and a ram rod (86). The end of the ram rod (86) which is remote from the ram cylinder is engageable with one of series of anchor members (85a, 85b, 85c) mounted on a platform, in a circle or on an arc of a circle. The end of the ram rod (86), when disengaged from an anchor member, is guided to an adjacent anchor member along a circular, or arcuate, guiding means (89). This mechanism is suitable for the rotation of a support frame (15) of a large dish (12) of a solar collector antenna about a vertical axis (20), as part of the arrangement whereby the dish support frame (15) is moved - for example, to enable the dish to track the sun.</p> |
