| 摘要 |
<p>PROBLEM TO BE SOLVED: To punch out knock-outs with ease and reliability without making visual errors in measuring distances in the knock-out structure of a box for wiring and piping which is provided with inner knock-out portions and outer knock-out portions. SOLUTION: An inner anchoring portion 11, to which a punching tool can be anchored, is formed on the outer face of an inner knock portion 5, and an outer hook portion 12 to which a punching tool can be hooked is formed on the outer face of an outer knock-out portion 6. The inner hook portion 11 and the outer hooked portion 12 comprise the inner knock-out portion 5 and the outer knock-out portion 6, and allow a removing tool to be hooked to the outer face of the inner knock-out portion 5 and the outer face of the outer knock-out portion 6. First connecting portions, which connect the inner knock-out portions 5 with the outer knock-out portions 6 and third connecting portions, which connect the outer knock-out portions 6 and the sidewalls are formed. The connecting strength of the third connecting portions is made higher than that of the first connecting portions, so as to prevent the outer knock-out portions 6 from being punched out together with the inner knock-out portions 5, when the inner knock-out portions 6 are punched out.</p> |
