Patent ID: 6948297

Claim:
A method for detecting an incipient position of meshing engagement between a thread of a vessel and a thread of a cap, comprising the steps of: holding the cap above the vessel with a capping head; lowering the capping head so that the cap is fitted around the mouth of the vessel; stopping the lowering of the capping head at an elevation where a distal end of the thread of the cap can engage with the distal end of the thread of the vessel; rotating relatively the thread of the cap and the thread of the vessel at the elevation where the lowering of the capping head has stopped; measuring a change of torque acting on the cap with a torque detector as the distal ends of both the threads contact with each other during their relative rotation; and detecting the incipient position of meshing engagement where the distal ends of both threads first contact with each other on the basis of the change of torque while detecting an angular position of rotation by an angle detector.