| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protection cap which can protect a drilled section necessary for ground improvement or soil investigation on a runway and the like, maintain the function of the runway and the like, and prevent human errors such as omitting to tighten a lid. <P>SOLUTION: A protection cap 2 comprises a main body 20 having a bulging part 26 on its interior wall, a lid body 40 covering an opening of an upper part of the main body, and a fastener 61 detachably fixing the lid body on the main body 20. The fastener 61 includes a bolt 65 having a head 63 which is caught by a top surface side of the lid body, and a lock bar 71 screwed into a bolt shank part 64 and fastening the lid body 40 and the bulging part 26 between the bolt head 63 and the lock bar 71. On an interior wall of the main body 20 and an outer periphery of the lid body 40, threads for screwing the lid body 40 and the main body 20 are cut. Consequently, the strength of the protection cap as a whole is increased so that the lid body does not come off from the main body even when receiving a complicated load in a vertical direction or a horizontal direction. In addition, the lid body projects if screwing is insufficient, so that it is possible to visually check if tightening of the lid body is omitted or the lid body is loosen. <P>COPYRIGHT: (C)2012,JPO&INPIT |
