Patent attributes
An apparatus and method for transferring torque on a rig. The apparatus comprises a central body having a central passage, and a first plurality of splines formed within the central passage and a second plurality of splines formed on a bottom sub, and wherein the first plurality of splines and the second plurality of splines cooperate to engage and transfer the torque applied to the central body. A third plurality of splines may be formed within the central passage, and a fourth plurality of splines formed on a top sub may be included that cooperates to engage and transfer the torque applied to the cental body with the third plurality of splines. In one of the preferred embodiments, the top sub is connected to a top drive of a rig. The apparatus may further comprise a first threaded cap engaging that contains an opening in communication with the central passage. A wireline is disposed within the opening.