| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide both of maintenance and access passages which cross each other with a level difference, and to enable passing in the access passage divided by a crossing portion to be blocked by a passage component member during maintenance.SOLUTION: A crossing portion cover member 12 is rotatably provided above a maintenance passage 7 in a crossing portion of both of maintenance and access passages 7, 11 so that it becomes a floor plate of the access passage 11 except when maintenance is performed and it is detached from above the passage so as not to disturb the passing in the maintenance passage 7 when maintenance is performed. Meanwhile, a crossing portion guard member 15 is provided as a guard fence of the crossing portion, and the access passage 11 is blocked by both the members 12, 15 in front of the crossing portion.</p> |
