Patent ID: 6971683

Claim:
A joint for tubings with which one end of a tubing inserted into an internally threaded bore of a nut member is externally fitted to a joint main body, an internal thread of said nut member being tightened against an external thread of the joint main body for supporting the one end of the tubing, wherein a control ring which is externally fitted to the external thread of said joint main body, and which, in tightening of said nut member, can adjust the degree of tightening of said nut member, being sandwiched between a stopper portion in the shape of a circular flange that is formed on a rear side of the external thread of said joint main body and a bore peripheral face of the internally threaded bore of said nut member; said control ring has a first end face which is brought into contact with the bore peripheral face of the internally threaded bore of said nut member, and a second end face which is brought into contact with the stopper portion of said joint main body when said nut member is tightened; and said first end face is formed such that, by making the friction torque which is applied to said first end face by the bore peripheral face of said internally threaded bore greater than the friction torque which is applied to said second end face by said stopper portion, said nut member is turned together with said control ring when said nut member is tightened.