| 摘要 |
PURPOSE:To enable the control of tightening length in such a way as to be within the predetermined tightening torque range by using a tightening allowance as a difference between a distance from a coupling to the end of a pipe before connection and a measured value from the end of the pipe to the coupling temporarily tightened. CONSTITUTION:A cylinder 72 is operated to lift a rack 73 up to a chucking line CL and the moving distance L1 of a differential transfer 75 is measured when a position transducer member 77 is caused to come in contact with the end of a steel pipe 1 with a cylinder 72, and the value obtained is fed to an arithmetic and control device 8. Then, the cylinder 72 is operated to lower the rack 73 from the chucking line CL and a mounting device 6 chucking a threaded coupling 4 is shifted to the side of a steel pipe 1. Thereafter, the coupling 4 is temporarily screwed into the threaded part of the steel pipe 1, while a driving device 63 is being rotated. In this state, the rack 73 is again lifted and then the moving distance L2 of the transfer 75 is measured when a member 77 is made in contact with the end of the coupling 4 with the cylinder 76, and the value obtained is fed to the control device 8. Then, a difference LM between the measured values L2 and L1 is obtained with the device 8 and a tightening allowance T remaining after the temporary tightening is obtained from a screwing reference value LH from the given coupling end, and the coupling 4 is then tightened. |
