Esikiristystyökalu ja menetelmä mutterin kiristämiseksi

摘要

The pretensioning tool (10) for stud bolts (5) comprises a body (1), which can be supported against a surface of a part that is clamped by the stud bolts (5), a gripping means (2) for gripping a free end of a stud bolt (5), and at least one hydraulic cylinder (3) comprising a piston (4) that is connected to the gripping means (2) for exerting a force on the gripping means (2) in the axial direction of the stud bolt (5). The gripping means (2) comprises magnetic material, and the pretensioning tool (10) comprises a sensor (6) for measuring the movement of said magnetic material. The invention also concerns a method for tightening a nut (9) by using the pretensioning tool (10).