| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To avoid contact with a boring blade when punching an aperture in a wall material. <P>SOLUTION: A recess 13 deeper than a front edge 12a is formed at a part corresponding to a trace H of the boring blade around a through-hole 14 in a box cover 11. The recess 13 is formed by recessing from the part corresponding to the trace H of the boring blade to the through-hole 14 on the front edge 12a of a flat-board part 12. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
