Abstract: In a ram boring machine having a striking piston that can be moved axially in a housing and whose movements are controlled by a control pipe that is connected to a compressed air hose and is mounted in an elastic intermediate piece arranged in the housing, arranging the elastic intermediate piece on the control pipe and/or in the housing facilitates the assembly of the intermediate piece. Furthermore there is less damage to the housing, the control pipe and the compressed air hose and even the control pipe can be mounted and disassembled easier.

Abstract: A ram boring machine having a striking piston that is axially displaceable in a housing, of which the forward and backward movement is controlled by a control sleeve connected to a supply hose and which engages in a cylinder chamber of the striking piston, and by one or more corresponding control openings in the striking piston, wherein the control sleeve is loaded both axially and torsionally, has axial and rotational stops and is rotatable and axially displaceable in a guide sleeve arranged at the rear end of the housing.

Abstract: An inclination sensor, in particular for measuring an inclination of service lines and/or ram boring machines, comprising a pendulum arranged in a measuring cell and at least one displacement sensor measuring the deflection of the pendulum. The pendulum comprises a body moving on a circular arcuate path in the measuring cell, the length of the pendulum being the same as the radius of the path. In this way a pendulum length can be obtained that is larger than the diameter of the measuring cell so as to obtain a large deflection of the body for a given angle and thereby achieve high sensitivity and accuracy of measurement.

Abstract: In a process for welding a pipe string driven horizontally into the ground to a follower pipe, the pipe string buried in the ground and the follower pipe are rotated. A welder then does not need to make vertical welds but can form the weld seams in a position that is most comfortable for him.

Abstract: In a self-propelled ram boring machine, in particular for making earth bores, having a striking tool at the leading end of a cylindrical housing, a striking piston movable to subject said striking tool to ramming blows, said striking piston being driven with pulsating, translatory working strokes, the striking tool is mounted in the housing to rotate about the axis of rotation and comprises kinematic means cooperating with the housing to change a translatory movement following each blow of said striking piston into a gradual rotary movement, and pneumatically operable means for initiating or interrupting the rotary movement.

Abstract: A ram boring machine for laying service lines in the ground without excavation, having a striking piston axially displaceable in a tubular housing and driven by means of a pressure medium via a supply hose connected to the housing, in which the supply hose is connected to the front end of the housing in the direction of advance and does not obstruct work on new pipes pushed into the passage made in the ground or drawn in simultaneously by the ram boring machine.

Abstract: A ram boring machine having a pull-and-turn reversing gear which comprises a striking piston axially displaceable in a tubular housing and a rotatably mounted control pipe with control openings such that forward and backward movement of the machine is controlled by moving the control openings over corresponding radial control openings in the striking piston, the control pipe having at least two parts with the rear part (viewed in the ramming direction) being connected to a supply hose, being relieved of the working pressure, and being connected to the bearing pipe by way of a force-loaded locking device which can be unlocked axially by traction on the supply hose against the loading force. This arrangement on the one hand prevents undesired reversal and on the other hand enables reversal to be effected under pressure.

Abstract: An apparatus for making tunnels and for laying supply lines in the ground comprises an earth displacing machine which is guided by a sword projecting out of the ground to allow the attachment of a power drive engaging the free end of the sword, and makes it possible to lay the supply lines accurately over long stretches, in particular along walls or the line of roadways or paths or the like.

Abstract: In a ram boring machine for laying pipelines without trenching, a double blade that is axially moveable against a compression spring is housed in an impact tip and projects through slots in the impact tip. The double blade is struck by a striker piston and moves, during the breaking-up of an old pipe laid in the ground, substantially independently of the ram boring machine or of its housing. In this way substantially all the impact energy of the piston is used for the benefit of the breaking-up operation.

Abstract: A hydraulically driven vibrator, for example, of the kind used for driving or extracting sheet piles comprises a number of out-of-balance masses which are all rotatably mounted side by side for rotation about a common axis. The masses are arranged in at least two pairs, one pair being rotated synchronously with the other pair, but in an opposite direction in such a way that on rotation the masses produce vibratory forces which are additive in a direction longitudinally of the vibrator, but mutually cancel each other out in a direction transversely of the vibrator. The pairs of masses are coupled by driving chains or toothed driving belts to oppositely rotatable drive outputs of a hydraulic motor which is offset longitudinally of the vibrator from the common rotational axis of the pairs of masses. Preferably one pair of masses is keyed on a drive shaft and another pair of masses are rotatable around the drive shaft and are mounted between the two masses forming the first pair.