Abstract: A device for welding together coaxial tube sections, comprising a cage adapted to surround the extremities of said tube sections, and provided with sleeves to be clamped on said tube sections for aligning the latter, guiding means for welding electrode carriers being connected to said sleeves which are adapted to guide welding electrodes and associated equipment along the welding seam to be formed between said tube sections.

Abstract: A device for performing soil inspection by means of a tube to be driven into the soil, comprising driving means which grip around the tube substantially coaxially said driving means comprising either a cylinder with a hollow piston rod or pairs of opposed driving wheels. Auxiliary means are provided for facilitating soil inspection operations with such a device, such as an improved pressing and pulling head, and means for signal transfer from a measuring cone towards measuring instruments at the soil surface.

Abstract: A method and a device for introducing a tubular assembly into the soil, which assembly consists of two or more elongated strips with a curved cross-section, made of an elastically flexible material, which strips are unwound from corresponding drums and are being united at adjacent edges when being unwound, and are separated again when being rewound on said drums. The driving force is derived from the rotational movement of said drums. The assembly can be used for introducing drainage tape into the soil, for introducing a sounding probe into the soil, for cutting soil samples and for similar purposes.