Abstract: A drilling device which can be lowered in a drill hole consists of a drive device, a drill which is rotated by this drive device and a clamping device formed as a unit which can be engaged with the inside wall of the drill hole and serves to transfer the torque of the drive to the drill. The drill consists of a ring-shaped housing, the outside diameter of which corresponds with the diameter of the drill hole and the upper part of is closed off by a plate. The housing contains several cutting tools which are equipped with bore crowns which serve to cut out a drill core and which are arranged at uniform distances and parallel with the longitudinal axis of the drilling device. Using additional drive devices, the cutting tools are designed to impart impact impulses and/or additional rotational movements in an axial direction. All drive devices are fluid actuated in such a manner that the clamping device is actuated initially and the drill is subsequently activated by the increasing pressure of the fluid medium.

Abstract: A device for the control of the internal pressure in a drill pipe or tremie is disclosed. The tremie is used in footings and especially in the construction of compressed concrete footings. The tremie has a valve located in a lid that serves for the tight seal of the tremie. The valve is subjected to a counter-pressure which is greater than the effective power of the internal pressure of the tremie. A hoisting cable is connected to the valve stem and the power of the hoisting cable under normal operating conditions in combination with the internal pressure of the tremie is large enough to overcome the counterpressure. The valve is shifted to vent the internal pressure of the tremie when the same is rapidly removed from the footing bore due to a decrease in ground friction.