| 摘要 |
<p>PROBLEM TO BE SOLVED: To house a suction grill or a ceiling panel in a prescribed position and safely elevate or lower it by providing a temporary elevation stop part on the way of the elevation or lowering of the suction grill or the ceiling panel. SOLUTION: A suction grill 3 is suspended on ends of wires 4 and the other ends of the wires 4 are wound/lowered by a pulley so that the suction grill 3 is elevated or lowered. The wires 4 are guided by a support guide. The wire 4 4 of the support guide is provided with sensors for detecting wire length and swing. When the suction grill 3 is elevated toward a housing position from a lowered position, the winding of the wires 4 for suspending the suction grill 3 is stopped for a prescribed time at a swing preventing stop position in the vicinity of the housing position 2a, and then, the wires 4 are wound so that the suction grill 3 is housed in the housing part 2a of the ceiling panel 2. The swing of the suction grill 3 can be suppressed by stopping the suction grill 3 at the swing preventing stop position for the prescribed time.</p> |
