Patent ID: 6532648
Filing Date: 2003-03-18
Classification: B23P,B25B,E21B,G05D,Y10T

Abstract:
An apparatus for performing a wrenching operation to fixedly connect together an externally threaded tube having an externally threaded portion and an internally threaded tube having an internally threaded portion, said apparatus comprising:a rotary drive device for rotating said externally and internally threaded tubes relative to each other with said externally and internally threaded portions engaging each other; an axial force applying device for applying an axial force to said tubes for at least a portion of a period in which said tubes are rotated by said rotary drive device relative to each other, without generation of a tightening force between said tubes; a torque detecting device for detecting a wrenching torque applied by said rotary drive device to said tubes for relative rotation thereof while said axial force is applied to said tubes by said axial force applying device; a physical quantity obtaining device for obtaining a physical quantity relating to a coefficient of friction between said tubes, on the basis of the wrenching torque detected by said torque detecting device and said axial force applied by said axial force applying device; and a terminating condition determining device for determining a terminating condition for terminating said wrenching operation, on the basis of said physical quantity obtained by said physical quantity obtaining device.