Abstract: The process is carried out using a press tool which has a plurality of dies which are arranged around a longitudinal axis and are radially displaceable with respect to this axis. The radially inner surfaces of the dies correspond to segments of the conical thread to be pressed. During pressing of a conical thread in cylindrical workpiece, the dies are first drawn apart in the radial direction and the workpiece is then pushed between the dies, along a length which corresponds to only a few thread turns. The dies are then pressed toward one another in order to press into the workpiece a short conical thread in which only the first thread turn may be formed to its full depth. After the dies have been drawn apart, the workpiece is displaced between the dies through a further length which once again corresponds to only a few thread turns. When the dies are pressed toward one another again, the previously pressed thread turns are pressed deep into the workpiece and additional thread turns are formed.

Abstract: A male conical thread of an elongated steel structure, e.g. a steel rod or wire of the type employed as reinforcement in pre-stressed concrete, for use in engagement with a matching female conical thread provided in a fixing sleeve or other nut means is formed by first shaping an end portion of the wire or rod, e.g. by grinding or hammering, into a cone that tapers down towards the end of the rod or wire and has a generally truncated smooth outer surface; then, the cone's surface is deformed by cold-pressing such that the thread is formed. Further, a press-die appartus is disclosed for use in such cold-pressing, e.g. at a construction site where steel reinforcements are mounted.

Abstract: A prestressed grouted anchor has a portion of an axially extending prestressed tension member grouted in a receiving material while the remaining portion of the tension member extends from the grouted portion. The remaining portion is separated from the grouted portion at a selected breaking point by reducing the tensile strength of the tension member as the result of exposing it to the action of heat, such as developed in an exothermic chemical reaction. If the tension member is prestressed and the resulting elastic elongation is maintained during the heating action with the elongation being greater than the elongation required under the heating action for effecting the severing of the tension member, then with progressive heat the tensile strength of the tension member is reduced and the elastic elongation progressively changes to plastic elongation with the tension member finally severing automatically at the selected breaking point.

Abstract: For their protection against corrosion, cables of high-strength steel wires, principally for use as tension members for post-stressable earth anchors or rock anchors, are treated with a corrosion protection material and furnished with a tubular sheathing member. In order to be able to surround completely all wires (3, 4) of the cable (2) with corrosion protection material, according to the invention the interior open spaces between the individual wires of the cable are in a first work operation filled with corrosion protection material, and in a second work operation immediately thereafter, when the strand is inserted into the tubular sheathing member, the annular interior open space between the cable and the tubular sheathing member is filled with corrosion protection material.