| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To beneficially manufacture in the manufacturing cost a plurality of kinds of circularity retaining frame corresponding to kinds of the size of through holes of a structure, which can be executed in a short time and of which the secure fire cutting off property of the through hole part can be formed in a simple constitution. <P>SOLUTION: The circularity retaining frame 10 is dividedly constituted of long side divided frames 12 corresponding to rectangular long sides of a through hole and short side divided frames 11 corresponding to rectangular short sides of the through hole. One side short side divided frame 11 is removed, and one end of the other halfway built-up frame A2 to which one side short side divided frame 11 is connected while riding on the other end side of the long side divided frame 12 is connectedly constituted against the other end of the halfway built-up frame A1 to which one side short divided frame 11 is connected while riding on the other end side of a pair of the long side divided frames 12. <P>COPYRIGHT: (C)2003,JPO</p> |
