A ground drilling device with a percussion piston for drilling into the soil, comprising at least one housing section for the percussion piston, wherein an insert is arranged in the housing between the drilling head tip and the percussion piston such that the insert transmits at least a portion of the energy of the percussion piston to the housing, and the insert is held in the housing by means of a shrinking adhesion connection.

A reverse-circulation drilling assembly having an overshot subassembly and a head subassembly. In the event retrieval of the drilling assembly by reverse-circulation fails, the drilling assembly can be retrieved using a secondary overshot.

A ground drilling device with a percussion piston for drilling into the soil, comprising at least one housing section for the percussion piston, wherein an insert is arranged in the housing between the drilling head tip and the percussion piston such that the insert transmits at least a portion of the energy of the percussion piston to the housing, and the insert is held in the housing by means of a shrinking adhesion connection.

A reversible pipe ramming tool used in horizontal pipe replacement operations. The tool is powered by a pneumatic hose attached to a rear end of the tool. The tool has forward and rearward fluid paths, which can either communicate with one another or stand in isolation. Fluid flow along the forward fluid path, when it is maintained in isolation from the reverse fluid path, causes the tool to move in a forward direction. Fluid flow along the forward fluid path, when it is maintained in communication with the reverse fluid path, causes the tool to move in a rearward direction. The tool is switched between forward and reverse by flowing fluid through a pilot fluid path in fluid communication with a valve. Movement of a shuttle within the valve selectively isolates the forward fluid path from the reverse fluid path.

A self-propelled drilling head for drilling in soil by means of a multi-stage method comprises the drilling head having a housing and a drilling head tip arranged in the housing, and a spacer provided on the drilling head tip, by means of which the drilling head tip is in contact with the housing in order to change the multi-stage method to a method with a reduced number of stages.

A device for dampening the action of a force on an electronic component, particularly one in the form of a probe, wherein the device comprises a receptacle space for the component, which is surrounded by an outer wall along a longitudinal axis, and transversely to the longitudinal axis there is situated an end closure of the receptacle space, wherein the outer wall and the closure comprise the same material and the material has a structural conformation which produces a dampening effect of the device in the longitudinal direction.

A percussion drilling device for drilling in earth includes at least one housing section for a main piston, and a ring insert arranged in the housing section in front of the main piston so that the ring insert transmits at least part of the energy of the main piston onto the housing. The ring insert is attached to the housing by a shrink-fit connection.

A ground drilling device comprising a housing, a lengthwise movable drilling head tip arranged in the housing, and a bearing for supporting the drilling head tip in the housing during its lengthwise movement.

A down-the-hole hammer drill bit retaining assembly is arranged to releasably retain a drill bit at a hammer arrangement of a percussion drilling apparatus. The retaining assembly includes a drive sub and a retainer ring. The drive sub has at least one indent to provide a fluid communication pathway for a flushing fluid extending over a radially outward facing surface of the retainer ring and into an internal region of the drive sub in contact with inwardly projecting splines.

A reverse-circulation drilling assembly having an overshot subassembly and a head subassembly. In the event retrieval of the drilling assembly by reverse-circulation fails, the drilling assembly can be retrieved using a secondary overshot.