How it works
With the patented TensionCam concept the clamp load is measured by using a special sensor module. It actually includes a fingerprint sensor! Instead of fingerprint patterns the module – when docked to the bolt head – makes images of a precision turned circular pattern in a cavity of the bolt head.
When tightened the bolt shank is tensioned in axial direction. Also the bolt head is deformed but in the perpendicular direction as the animated video clip shows. Practically it means that the diameter of the circle pattern is reduced with up to 0.04 mm once the bolt is fully tightened.
With special made algorithms the TensionCam image analysis of made images defines the diameter reduction and calculates the corresponding clamp load in the bolt. The resolution in the measurement of the circle diameter is down to 2 microns…!
For special applications TensionCam washers or nuts can be used. Here the circular pattern is turned on the side face of the washer or nut.