US Patent 9261207 Coupling with anti-rotational element

A threaded connection for engaging a first tubular and a second tubular with a threaded coupling. The threaded coupling has mill end teeth and field end teeth. Each tubular has a pin connector. The threaded coupling receives and engages both pin connectors. The threaded coupling has a controlled phase or a phase difference that limits the axial advancement of the pin connectors past a coupling midpoint. The threaded coupling has a relief groove that reduces the hoop stress if the mill end pin end and the field end pin end are not centered correctly at the coupling midpoint. The threaded coupling has a metal barrier formed by the phase difference and length of the screw thread helices which limit the axial advancement of each pin connector.