Patent ID: 7255181
Filing Date: 2007-08-14
Classification: E21B

Abstract:
1. A method for drilling holes in soil or rock material, the method comprising the steps of forming a borehole by a percussive and/or rotational movement carried out by a drill bit mounted on a drill rod assembly, introducing an envelope tube and/or a jacket tube into the borehole, transmitting impact energy introduced by the drill rod assembly partially centrally by the drill rod assembly onto the drill bit and partially via an impact shoe cooperating with the drill rod assembly onto the envelope and/or jacket tube, transmitting the impact energy from the drill rod assembly onto the impact shoe via an interposed impact ring and that the drill bit and the impact ring being coupled with the drill rod assembly by a plug-in connection, and providing complementary polygonal surfaces of the plug-in connection between the drill bit and the impact ring with the drill rod assembly.