Apparatus for use during connection of a length of pipe to the upper end of a drill string, preferably in a top drive drilling arrangement, and including a back-up tool for retaining the upper end of the drill string against rotation as the added length of pipe is connected threadedly thereto. This back-up...http://www.google.com.au/patents/US4625796?utm_source=gb-gplus-sharePatent US4625796 - Well pipe stabbing and back-up apparatus
