| 摘要 |
PURPOSE:To stabilize the distance and sliding contact between a lake and a screen by using a system in which during the lowering period of the lake, a lower roller is slided with an upper guide rail and an upper roller is slided with a lower guide rail, and during the rising period of the lake, both the rollers are slided with the lower guide rail. CONSTITUTION:A lake 9, having an upper roller 15 and a lower roller 16, is vertically moved by a hoister 7. Under the condition of III, the lake 9 goes down, while the lower roller 16 is slided with the upper guide rail 13 and also the upper roller 15 is slided with the lower guide rail 14. When the lake 9 reaches the lowering position IV, the lower roller 15 is guided by a guide plate 20 and slided with the lower guide rail 14. Under the condition, when the lake 9 is raised, slum 3 dammed up on the screen 2 is laked up, a wiper 22 is pushed down by the guide plate 27 at the pisition V, and the slum 3 laked up by the lake 9 is forcibly damped into a chute 5. Since both the rollers are put on both the guide rails in this way, the damping of slum can be made exactly. |
