Structure
of Stationary Dynamometers.
Influence of Pretension
The structure of dynamometers is always similar as a rule. A piezoelectric force sensor is mounted under high pretension between two massive plates, the base and the cover plate. A so-called pretension screw that is guided through the center of the sensor, connects the base and cover plate and ensures that the force sensor placed between them is pretensioned. This pretensioning is exceptionally important for two reasons. On the one hand, the structure requires the pretension in order to be able to record shear forces and measure them accordingly. On the other hand, the pretension ensures linear behavior of the dynamometer. Particularly with small forces, the behavior of the structure would be markedly non-linear without the pretension- ing.
Possibilities of the Pretension
Two possibilities exist for the pretensioning of the sensor with the stationary dynamometer. Vertical pretensioning is very well- known. It has been in use for many years. At the same time, horizontal pretensioning has come into increasing use in recent years. The two pretensioning methods will be discussed in the following