| 摘要 |
PROBLEM TO BE SOLVED: To easily maintain inserting amount of a pipe to proper amount by drawing peripheral lines at equal intervals in dimensions related to inserting amount into a pipe coupling in the longitudinal direction of a resin pipe inserted and connected into/with the pipe coupling and forming displays of characters and pictures between the peripheral lines. SOLUTION: A pipe coupling 1 has step parts 2, 3 at the inside from the inside. A holding ring 5, a washer 6 and an O-ring 7 are inserted into the step part 3 and are supported by a socket 8 screwed into a male screw 4. The holding ring 5 is provided with a claw 9 at an inner peripheral edge. When a resin pipe 21 is inserted into the coupling 1, the claw 9 is bitten into a surface of the pipe 21. In this case, a plurality of peripheral lines 30 are drawn in width W on a surface of the pipe 21 so as to display inserting amount W to be a depth up to the step part 2 of the coupling 1 of the resin pipe 21. By inserting the resin pipe 21 into the coupling 1 up to the peripheral line on an end edge side by performing pipe cutting by the peripheral lines 30, the inserting amount is always and properly secured.
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