Patent ID: 8322458

Claim:
A drilling rig, comprising a mast having top and bottom ends, a drilling drive displaceably mounted on the mast for movement over a maximum movement distance between an upper initial position and a lower end position at the bottom end of the mast, the drilling drive being displaceable during a first drilling step to a first drilling depth at which the drilling drive has reached its lower end position, a drilling element which is rotatably drivable and movable along the mast by said drilling drive, wherein the drilling element has: a continuous screw auger disposed below the drilling drive for creating a bore hole having an upper part in the first drilling step and a lower part in a second drilling step following the first drilling step, wherein the upper part extends below a surface to the first drilling depth and the lower part extends below the first drilling depth to a second drilling depth, the continuous screw auger having a cutting unit on its bottom end for removing earth material from the bore hole, and a feed helix extending over substantially the entire length of the continuous screw auger for conveying earth material removed from the upper part of the bore hole by the cutting unit toward the surface by rotary motion during the first drilling step and for conveying earth material removed from the lower part of the bore hole by the cutting unit toward the upper part during the second drilling step, wherein the continuous screw auger has a length that is one of approximately equal to one of the length of the mast and the maximum movement distance of the drilling drive, an extension which is connected to said continuous screw auger and extends upwardly through the drilling drive, the extension being longitudinally displaceable in the drilling drive in a downward direction during the second drilling step, drive pins disposed on an outside surface of the extension for transmitting torque of the drilling drive, and a displacement head disposed between said continuous screw auger and said extension, for forcing the earth material being conveyed by the feed helix from the lower part of the bore hole toward the upper part aside into the wall of the upper part of the bore hole directly above the continuous screw auger during the second drilling step, wherein the displacement head has a cylindrical displacement section having an outside surface having displacement elements disposed thereon, the diameter of said displacement section being approximately equal to the drill diameter.