Patent ID: 7567857

Claim:
A control unit for an unbalanced mass adjusting device in a vibration generator, in particular in a soil compaction machine, having an adjusting cylinder which is hydraulically adjustable to adjust a relative position of contrarotating unbalanced masses in the vibration generator, a control valve for adjusting the adjusting cylinder so that the vibration characteristic of the vibration generator is adjusted, and a control unit for triggering the control valve according to a pulse width modulation signal to adjust the relative position of the unbalanced masses as a function of the pulse duty factor of the pulse width modulation signal, wherein the control unit is connected to the control valve to trigger the adjusting cylinder according to a first level of the pulse width modulation signal so that the relative position of the unbalanced masses is adjusted in the direction of a first defined position and to trigger the adjusting cylinder according to a second level of the pulse width modulation signal so that the relative position of the unbalanced masses is adjusted in the direction of a second defined position.