Abstract: In a method for producing a concrete foundation for a wind power tower externally preloaded and made of precast concrete parts, a formwork for the concrete foundation is erected, core elements for producing passage openings in the concrete foundation for the loading elements are positioned and fixed on the formwork, and the concrete foundation is cast. A measurement reference system is established in order to position the core elements, at least one first positioning aid having an adapter device for a core element and having at least one reference segment is provided on the formwork. A corresponding concrete foundation is produced in accordance with the described method. A positioning device for orienting core elements in a concrete foundation comprises at least one first positioning aid, which has an adapter device for a core element and at least one reference segment for calibrating the first positioning aid.

Abstract: In a method for producing a concrete foundation for a wind power tower externally preloaded and made of precast concrete parts, a formwork for the concrete foundation is erected, core elements for producing passage openings in the concrete foundation for the loading elements are positioned and fixed on the formwork, and the concrete foundation is cast. A measurement reference system is established in order to position the core elements, at least one first positioning aid having an adapter device for a core element and having at least one reference segment is provided on the formwork. A corresponding concrete foundation is produced in accordance with the described method. A positioning device for orienting core elements in a concrete foundation comprises at least one first positioning aid, which has an adapter device for a core element and at least one reference segment for calibrating the first positioning aid.

Abstract: A sheet-stacking apparatus has a conveyor including a plurality of parallel upper belts extending in a transport direction for delivering a succession of sheets one at a time to a stacking station and a plurality of blow tubes each having a main portion extending in the direction. The main portions are interleaved with the upper belts and are each formed with a plurality of downwardly open holes. Respective tubular rivet bodies set in the holes have heads bearing upward against the respective tube main portions and form downwardly open nozzles. Interiors of the tubes can be pressurized with air to project jets of air downward from the nozzles of the tube main portions.

Abstract: It is provided in an electrochemical polishing and pickling method and apparatus for treating metal surfaces that an electrolyte stream (18) entering a casing (12) is divided into an anodic partial stream (20) and a cathodic partial stream (22). The anodic partial stream (20) flows past a dielectric wall (32) as well as the surface (10') to be polished or pickled, while the cathodic partial stream does not reach the surface (10') to be polished but instead is recycled directly into an electrolyte reservoir (30) after having passed the cathodes (24).