Abstract: A locking device and a locking method are provided for a tool holder of a rotary drilling rig. The locking device includes a sleeve, a locking pin, a movement system, and a control system. The sleeve and the locking pin are configured such that the sleeve engages around the locking pin with a form fit, such that the locking pin can be rotated in the sleeve about the longitudinal axis of the locking pin. As a result, the locking pin can be displaced laterally parallel to the longitudinal axis. The movement system has at least one electric motor and at least one shaft, wherein the shaft effects relative rotation of the sleeve and the locking pin by the force of the electric motor.

Abstract: An elevator for casing pullers with elevator links adapted for motorized opening and for the lateral approach to a casing which is to be pulled. One of the elevator links is constructed as a hook, into which a locking bolt of a power jack can be pivoted, which said power jack is copivotingly secured on the second movable elevator link and closes the elevator by retraction of the locking bolt.

Abstract: Pile extraction apparatus having a clamping device for clamping engagement with a pile. The device is suspended from a section of casing pipe by way of a universal joint. In this way the extraction apparatus may be raised and lowered by a commercially available pipe extraction machine.

Abstract: Method for sinking a cased borehole for producing cased pile foundations. The method uses an apparatus comprising a crane, a drilling appliance capable of being lowered into the borehole and a tube extraction machine with double-acting lifting cylinders for increasing the drilling pressure and for extracting the drop tube after the pile has been concreted. The drilling appliance is capable of producing a borehole with a larger diameter than that of the drop tube and can be fixed to the drop tube by means of a clamping device for withstanding the torque of the motor used for driving the drilling tool. In the method, the drop tube is axially secured and is prevented from locating with respect to the ground, a section of borehole having a greater diameter than the diameter of the drop tube is drilled, and subsequently the axial securement of the drop tube is released so that the drop tube slides downwards by a length corresponding to the length of the section of borehole drilled.

Abstract: A rotary boring head for earth and rock formations with pivotal wings which may be swung radially outwardly and which are provided with inclined return rails. Upon upward movement of the rotary boring head the earth mass presses upon the inclined return rails, so that the pivotal wings are reliably swung inwards again and cannot impinge on the bore tube.