摘要 |
A convex stripe 231 is disposed on the side surface of a coupler 20 and a step portion 53 of the cylinder member 50 is brought into contact with the upper surface of the convex stripe 231, to thereby engage the cylinder member 50 with the coupler 20 and also to fit a fitting projection 312 formed on a rising portion 31 into a fitting hole 51 of the cylinder member 50, thereby allowing the cylinder member 50 to be stretched over and installed on the coupler 20 and the side surfaces of rising portion 31, making difficult to dismount the coupler 20.
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