The short hydraulic casing oscillators have been designed in accordance with the latest technical know-how. Extremely sturdy construction guarantees worth-while use on site. By means of exact statical calculations in conjunction with higher quality material, an optimum conformity of loads, weight and material strength is achived.

The internal welding stresses, not easily determined for the statical calculation, and which would affect the construction considerably, are eliminated by means of stress relieving prior to machining. A prominent feature of the equipment in the clamping collar consisting of five links operating on the boring implement. The individual links surround the casing like chain so that a constant surface pressure is exerted on the casing circumference.