US Patent 7775298 Drilling assemblies and methods of drilling

Drilling assemblies and methods of drilling are disclosed. In one implementation, a drilling assembly includes a rotary drive apparatus configured to rotate a string of drill pipe having a cutting head at a drilling end thereof. A longitudinally elongated torque transfer tube apparatus is mounted to and extends downwardly from the rotary drive apparatus and is configured to longitudinally receive the string of drill pipe rotatably there-through. The torque transfer tube apparatus is isolated from rotation relative to the rotary drive apparatus and the string of drill pipe during drilling with the drilling assembly. A torque receiving structure is provided, and through which the torque transfer tube apparatus is upwardly and downwardly slidably received. The torque transfer tube apparatus and the torque receiving structure are isolated from rotation relative one another and the string of drill pipe during drilling with the drilling assembly.