A device for measuring the prestressing of a bolt 1 shows an axial half cross section that is used in particular to the closing of an enclosure under pressure of a resonance

摘要

Apparatus for measuring the pre-tension of a threaded bolt which is elongated by means of a tensioning unit and a screwed-in tensioning bo a measuring rod is inserted into a central hole in the threaded bolt and the difference in length is determined by means of a length measuring device. The measuring rod is guided in the housing of the tensioning unit, secured against rotation, and is threaded to engage a threaded bushing. The threaded bushing is longitudinally movable and secured against rotation in a bushing having external teeth. Rotation of the tensioning bolt is transmitted via gears to the threads on the measuring rod and converted into an up or down movement. The measurement may be made when the measuring rod comes to rest at the lowest point of the central hole.