| 摘要 |
<p>The superstructural machinery of a theatre consists of a scenery manoeuvring device for the lowering of scenery flats and as well as a spot pulling machinery for positioning and removing other properties (4). According to the invention the spot pulling machinery is arranged on traverses (13) that are movable relative to travelling rails (14). The point pull further comprises a drum winch having a motor (15), a gear (16) and a drum (10). In case of raising and lowering, respectively, of an object, the inventive arrangement may be caused to occupy an accurate position relative to the stage floor. Moreover the hoisting winch is so arranged that when the drum (10) has performed one revolution, it or optionally a reversing pulley will have moved such distance which corresponds to the diameter of the rope. It follows that the selected position on the theatre stage which the object is desired to occupy is well determined and that unintentional displacements of the hoisting spot do not occur during the raising and lowering, respectively, of even very heavy objects. Alternatively a displaceable reversing pulley (23) is provided from where the rope (8) travels across a further reversing pulley (25) whereby the hoisting spot for the rope (8) may also be secured. The point pulling units may also be made with dual suspension of properties (4) which are hereby prevented from rotating about a vertical axis.</p> |
