A mechanical structure based on serial stacking of level arm has been designed in order to amplify the ingoing force of the the harvester system. The outgoing force is applied upon the smart material. The deformation of the mechanical structure is based on flexural pivots using four truncated circular collars. The last amplification is based on the APA® (Amplified Piezoelectric Actuator) shell and already patented solution by Cedrat Technologies. The force amplification structure has been designed upon the request of a small volume allocated (0.3 cm3) and low frequency resonance (20 Hz) harvester