Vibration control system

摘要

Methods and apparatus for generating a linear vibratory output force having a variable amplitude. The force is generated by the cooperation of four rotating eccentric masses that are grouped in two pairs of two masses. The masses in each pair are counter-rotating (i.e., they rotate at the same speed but in opposite directions). The phase relationship between the two pairs is adjustable. For example, the phase of one pair can be advanced while the phase of the other pair is retarded by an equal amount, thereby changing the amplitude of the output force without changing the direction along which the force acts, and also without changing its frequency if desired.