The preferred embodiments of the present invention provide an apparatus structured and arranged to securely clamp an object to a support structure. The excitation and measurement piezoelectric devices are attached to the beam adjacent to each other at one end of the beam. As regards the control mechanism, it is proposed to turn on the first switching element later if shoot through currents occur, and to turn on the first switching element sooner if conduction of the freewheeling diode occurs. Each plunger further includes an axle on which two wheels are opposingly mounted.