| 摘要 |
PROBLEM TO BE SOLVED: To provide an indicating device that prevents troubles such as leaking of liquid after piping work caused by forgetting to tighten bolts and nuts or not tightening them insufficiently. SOLUTION: A flat washer 6a that has a flat part 6b on the outer circumference and a tapered part 6c on the inner circumference is laid facing a protruding surface of a tapered part 6c each other either between a head part 2b of a bolt 2 and a protruding part 1b or between a protruding part 1b and a nut 3 or both of them. Then, a colored surface 6e is made on a protruding surface of, at least, a tapered part 6c located on each flat washer 6a. The conditions of fastening a bolt and a nut 2, 3 are shown by covering a colored surface 6e with each flat washer 6a after each flat washer 6a is buckled into flat by fastening a bolt and a nut 2, 3. The conditions of fastening the bolt and the nut 2, 3 can be easily checked by just looking at the colored surface 6e on the flat washer 6a.
|
