A mallet is described that has at least one cleft, in such a structure that the stress wave created during impact has longer travel way than the length of the mallet as measured along the impact line. This mallet induces longer-lasting and weaker stress wave(s) in the anvil as compared to a solid mallet having the same outer dimensions and more or less the same weight. The Cleft-Mallet increases the effectiveness of the strike, while decreasing the stresses in the anvil.

A mallet is described that has at least one cleft, in such a structure that the stress wave created during impact has longer travel way than the length of the mallet as measured along the impact line. This mallet induces longer-lasting and weaker stress wave(s) in the anvil as compared to a solid mallet having the same outer dimensions and more or less the same weight. The Cleft-Mallet increases the effectiveness of the strike, while decreasing the stresses in the anvil.

A vibro replacement probe includes a ramming tube that is connected with a filling piece that includes a feed tube as well as a filling funnel and/or a hose connection flange. The feed tube is firmly connected with a vibrator that has a mechanism for pivoting attachment to the leader of a construction machine, wherein the mechanism includes a connection part that is connected with the vibrator so as to pivot and that can be attached to a carriage that is displaceably guided on the leader. Furthermore, a construction machine has such a vibro replacement probe and a method equips a leader of a construction machine with such a vibro replacement probe.

A vibro replacement probe includes a ramming tube that is connected with a filling piece that includes a feed tube as well as a filling funnel and/or a hose connection flange. The feed tube is firmly connected with a vibrator that has a mechanism for pivoting attachment to the leader of a construction machine, wherein the mechanism includes a connection part that is connected with the vibrator so as to pivot and that can be attached to a carriage that is displaceably guided on the leader. Furthermore, a construction machine has such a vibro replacement probe and a method equips a leader of a construction machine with such a vibro replacement probe.

A machine, method and system for installing helical foundation piers that sues a driving tamper connected to a rotary tool to drive helical piers into the ground. Once the pier reaches the target depth, the tamper is decoupled, and counter rotated away from the pier. While it is withdrawn the soil between the driven and pier and the driving tamper is compressed by intermittent downward action of the tamper.

A machine, method and system for installing helical foundation piers that sues a driving tamper connected to a rotary tool to drive helical piers into the ground. Once the pier reaches the target depth, the tamper is decoupled, and counter rotated away from the pier. While it is withdrawn the soil between the driven and pier and the driving tamper is compressed by intermittent downward action of the tamper.

A depth vibrator for compacting soil, comprising a rotary drive (3); a drive shaft (4), which is rotatingly drivable about a rotary axis (A) by the rotary drive (3) in a first rotation direction (R1) and in an opposite second rotation direction (R2); a primary mass body (5) connected non-rotatably to the drive shaft (4) and rotates together with the latter about the rotary axis (A); a secondary mass body (6), which is movable into a first rotation position (P1) relative to the primary mass body (5) by rotation of the drive shaft (4) in the first rotation direction (R1) and which is movable into a second rotation position (P2) by rotation of the drive shaft (4) in the second rotation direction (R2). In the first and second rotation position (P1) the secondary mass body (6) can be rotated together with the primary mass body (5) about the rotary axis (A); and the center of mass (S6) of the secondary mass body (6) and the center of mass (S5) of the primary mass body (5) have different radial distances from the rotary axis (A).

A depth vibrator for compacting soil, comprising a rotary drive (3); a drive shaft (4), which is rotatingly drivable about a rotary axis (A) by the rotary drive (3) in a first rotation direction (R1) and in an opposite second rotation direction (R2); a primary mass body (5) connected non-rotatably to the drive shaft (4) and rotates together with the latter about the rotary axis (A); a secondary mass body (6), which is movable into a first rotation position (P1) relative to the primary mass body (5) by rotation of the drive shaft (4) in the first rotation direction (R1) and which is movable into a second rotation position (P2) by rotation of the drive shaft (4) in the second rotation direction (R2). In the first and second rotation position (P1) the secondary mass body (6) can be rotated together with the primary mass body (5) about the rotary axis (A); and the center of mass (S6) of the secondary mass body (6) and the center of mass (S5) of the primary mass body (5) have different radial distances from the rotary axis (A).

A method and a mandrel for forming a cavity at a target location. The mandrel may include a main drilling shaft, a plurality of T-shaped elements, a hollow-cylindrical-shaped element, and a plurality of parallelepiped-shaped stiffener plates. The main drilling shaft may include a hammer insertion part positioned at a first end of the main drilling shaft, a bore head positioned at a second end of the main drilling shaft, and a medium part positioned between the hammer insertion part and the bore head. The plurality of T-shaped elements may be mounted adjacently around the medium part in a way such that forming a closed octagonal from a top-view of the mandrel. A first size of a first cross-section at a first location from a top-view of the plurality of T-shaped elements around the medium part may be larger than a second size of a second cross-section at a second location from the top-view.

A method and a mandrel for forming a cavity at a target location. The mandrel may include a main drilling shaft, a plurality of T-shaped elements, a hollow-cylindrical-shaped element, and a plurality of parallelepiped-shaped stiffener plates. The main drilling shaft may include a hammer insertion part positioned at a first end of the main drilling shaft, a bore head positioned at a second end of the main drilling shaft, and a medium part positioned between the hammer insertion part and the bore head. The plurality of T-shaped elements may be mounted adjacently around the medium part in a way such that forming a closed octagonal from a top-view of the mandrel. A first size of a first cross-section at a first location from a top-view of the plurality of T-shaped elements around the medium part may be larger than a second size of a second cross-section at a second location from the top-view.