Patent attributes
A pipe joint locking device which prevents accidental loosening of a pipe joint after tightening and with which a sealing property of a seal portion of the pipe joint is not impaired even if a force for rotating a pipe member acts on the pipe member. The device is formed of: a first component member 11 including a mounting portion 21 to be mounted to a joint member 2 having an external thread while prevented from relative rotation, a cover portion 22 to be brought into contact with an outer peripheral face of a cap nut 5 from a lower side, and a coupling portion 23 to be brought into contact with a pipe member 3 from the lower side; and a second component member 12 including a cover portion 31 to be brought into contact with the outer peripheral face of the cap nut 5 from an upper side and a coupling portion 32 to be brought into contact with the pipe member 3 from the upper side. The coupling portion 23 of the first component member 11 and the coupling portion 32 of the second component member 12 are coupled to be fixed to a portion 3a of the pipe member 3 protruding from the cap nut 5.