Patent Number: 8,875,803

Title: Method for tightening bolt connection by elongation of bolt

Abstract: The present invention relates to a method for tightening a bolt connection through elongation of the bolt where strokes of a power element, especially a hydraulic cylinder, are converted into a rotational movement of a tightening tool. The method according to an embodiment of the present invention is carried out in at least two steps. As a first step, the bolt is first tightened to a predetermined snug torque. As a second step, the bolt is then tightened up through a predetermined number of complete strokes of the power element of the power wrench. In this way, a torque method is combined with a rotational angle method that is controlled by the number of strokes.

Inventors: Galehr; Lothar (Tschagguns, AT), Zint; Manuel (Vandans, AT), Wachter; Juergen (Gortipohl, AT)

Assignee: Liebherr-Werk Nenzing Ges.m.b.H

International Classification: B25B 21/02 (20060101); B25B 23/145 (20060101); B25B 23/14 (20060101)

Expiration Date: 2019-11-04 0:00:00