Abstract: This invention relates to an apparatus for testing the gas-tightness of joints between hollow bodies, for example, pipes. With the apparatus, a test space with two concentric chambers of variable sizes is formed. The outer one is filled with a gaseous test medium and the inner one with an incompressible pressurized medium. It is thereby possible to reduce substantially the quantity of the gaseous test medium. The safety of the entire apparatus is improved extraordinarily.

Abstract: Apparatus for testing the impermeability to gases of connections between pieces of piping, especially between pipes and sleeves, utilizes tow elastic sealing bodies that are spaced apart from each other. The sealing bodies can be pressed against the surfaces of the pipes in response to the application of axial stresses to thus confine the testing location which is to be monitored. The first sealing body is located in the pipe inwardly of the testing location and is adapted to be pressed from within against the surface of the pipe, and the second sealing body can be pressed against the periphery of the sleeve. This renders it possible to test, already within the manufacturing plant, even short pieces of piping for impermeability to leaks.

Abstract: A machine for clamping a pipe socket between clamping jaws of a socket screwing-on machine as a function of torque wherein, the clamping jaws of the screwing head are advanced to the socket via a thrust-crank drive of adjustable effective range. Without the need to exchange clamping jaws and other associated parts, it is possible to cover a large clamping range, and the clamping force which increases with the torque can be adjusted.

Abstract: A power tongs for threadedly connecting together pipes which are to constitute casings for boreholes has a platform for a reciprocable slide which supports a power-driven threading clamp and a counter device. The clamp and the counter device are connected to each other by several level compensating hydraulic cylinders each of which is movable horizontally within limits relative to the slide against the opposition of resilient support elements. The upper end portions of the cylinders are connected to a holding plate for the clamp.