| 摘要 |
PURPOSE: An anti-sharp fall building shutter is provided to ascend a shutter plate easily by the rapid rotation of a small-sized gear, and to prevent the sharp fall of a shutter by supporting a load of a shutter by the slow rotation of a large-sized gear. CONSTITUTION: An anti-sharp fall building shutter comprises a small-sized gear(8) and a large-sized gear(7) fixed to a rotary shaft(3) rotated to take up a shutter while ascending a shutter plate(1), connected to a bearing(4) to rotate or idle the small-sized gear and the large-sized gear, and connected to another large-sized gear and small-sized gear operated by a speed reducer(5) connected with a motor(6) respectively by a chain(2); on ascending a shutter, the small-sized gear formed to the rotary shaft is rotated, but the large-sized gear is idled, so that the rotary shaft is rotated rapidly; on descending a shutter, the large-sized gear formed to the rotary shaft is rotated, but the small-sized gear is idled, so that the rotary shaft is reversed slowly to control the speed of opening and shutting a shutter proportionally.
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