| 摘要 |
A moving-loop advertisement device has a rolling screen that surrounds a driving roller and three driven rollers to increase the quantity of the advertisements printed on the rolling screen. A position sensor is applied to detect labels formed on the rolling screen so as to pause the movement of the screen. A coil or helical ribs with opposite twisting directions is further provided on either or both the driving roller and the driven roller. When the rollers start to rotate, the rolling screen is moved upward or downward to sequentially present different advertisement information printed thereon. Meanwhile, as the rotation of the coil or helical ribs, tension forces with opposite directions occur and apply on the rolling screen to maintain the surface of the rolling screen in a smooth flat state.
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