Abstract: A device for connecting and disconnecting pipe segments of drill pipes, includes an adjustable retaining element in the form of a collar. For firmly holding the pipe segments introduced into the collar, segments acting as clamping jaws are used for retention. The clamping jaws can be adjusted vertically by servo elements for reducing the receiving diameter. The segments have a conical outside contour and a conical guide on the collar and a corresponding conical guide is provided on the collar, so that, when the segments are vertically displaced, the receiving diameter is reduced.

Abstract: An oil and gas well drilling system is provided that includes a top drive assembly having an output shaft; and a pipe running tool having a top drive extension shaft connected to the top drive output shaft and engageable with a pipe string to transmit translational and rotational forces from the top drive assembly to the pipe string, wherein the pipe running tool further includes a cementing pipe connected to the top drive extension shaft and having a fluid passageway which receives cement during a cementing operation.