Abstract: An apparatus for longitudinal splitting, in particular longitudinal slitting, of pipes laid underground and for the simultaneous trenchless pulling-in of a new pipeline comprises a carriage in the form of a frame, in which a cutting wheel for cutting open the pipe wall and a support roller, which serves as an abutment and is supported on the pipe wall, are arranged above one another. The carriage or frame has a base which engages in a form-fitting manner in a frame-like window of a pull and/or push linkage.

Abstract: In apparatus for producing and expanding earth boreholes and for destroying and replacing underground pipelines or for driving in pipes, a feed drive and a rotary drive having a plug-in coupling comprising a chuck and a locking portion at the end of a string is located in a frame. The string comprises a plurality of sections or lengths having an internal screw thread at one end and an external screw thread on the locking portion at the other end, which at the same time is provided with a key face to hold fast said string section while it is screwed together with the next following string section.

Abstract: An apparatus for widening microtunnels and/or for the destruction and replacement of ground-laid pipework and for the laying of new pipework possesses a tool which displaces the earth and/or destroys and/or displaces pipework laid in the earth, having a housing which is provided with an axial linkage seating, for example a housing passage for a linkage and with a linear drive which moves the tool, for example, on the linkage automatically from a launch pit to an arrival pit and simultaneously lays a follow-up pipe or a follow-up cable in the earth.

Abstract: In an apparatus for drilling in earth, a push-pull linkage, especially a ladder-type linkage consisting of individual sections connected together in each case by a plug-in coupling, is connected to a push-pull drive, and a stationary locking pawl and a thrust pawl which is moveable in the longitudinal direction of the linkage and is connected to the drive, with two mutually opposite directions of action, can each be brought into active connection with the linkage in order to move the linkage forward stepwise and lock it temporarily after each movement step.

Abstract: In directional boring using a boring apparatus having a driven string and a drill head with an excavating tool moving in an orbit about the longitudinal axis of the string, the tool moves with substantially constant angular velocity when boring straight ahead, but when boring along a curve it is stopped and set in vibration in order to obtain more accurate control of the curve.