Fixing screw with clamping force indication

摘要

The fixing screw has the bearing surface of the screw head coated with a piezoceramic, an electrically insulating and an electrically conductive material, the conductive layer contacted by a charge amplifier (5) at a point which is accessible during the tightening of the screw. The signal provided by the charge amplifier is electronically processed for controlling the tightening of the screw, for obtaining a required screw clamping force.