A joint connecting a pair of members rotatable about a common axis end to end includes a first member having a threaded end portion and a non-circular exterior surface rearwardly of the threaded end portion, a second member having a threaded socket wherein the threaded end portion of the second member...http://www.google.ca/patents/US20030166418?utm_source=gb-gplus-sharePatent US20030166418 - Drill string joint
