Method and apparatus for tightening or loosening screw-type connections
AssigneeVeb Chemieanlagenbaukombinat Leipzig-Grimma
InventorsHanno Wenske, Arnold Gallien, Martin Kauschinger, Klaus Unger, Josef Brendel, Lutz Lampe
Life of this patent
Estimating the term…
Abstract
A method and apparatus for tightening or loosening screw-type connections, in which the screw bolt is stimulated to oscillate longitudinally, the natural frequency of the bolt is measured and the excitation frequency is made to follow the changing natural frequency during the bolting process with a minimum, necessary excitation energy, so that the screw bolt attains a permanent state of resonance.
Claims10
Method for tightening or loosening screw-type connections using oscillation energy, a screw bolt or a nut being turned preferably by motor, comprising stimulating the screw bolt to oscillate longitudinally, measuring the natural frequency of the screw bolt and controlling the excitation frequency during the bolting process to follow the changing natural frequency, so that the screw bolt resonates, and adapting the excitation energy in such a manner, that the oscillating screw bolt in the phase of maximum stretching or contraction is largely relieved of tensile or compressive stresses respectively.
In an apparatus for tightening and loosening screw-type connections using a manual or motor-operated driving mechanism and a unit for measuring the tension on a screw bolt directly or indirectly, the improvement comprising vibrating and sensing means adapted to becoupled to the screw bolt, said vibrating and sensing means comprising a piezoelectric element means for vibrating said bolt and sensing the vibrations thereof, said apparatus further comprising an alternating voltage generator connected to the piezoelectric element means for vibrating said bolt, a differentiating element coupled to said alternating current generator and to said vibration and sensing means for comparing the excitation and natural frequency of said bolt, and a feedback connection between the differentiating element and the alternating voltage generator for controlling the frequency of said alternating current generator to equal the natural frequency of said bolt.
Dependencies are inferred from the claim text.