Patent ID: 7942229

Claim:
A method for damping vibrations in a power transmission system, the power transmission system including a first power transmitting component, a second power transmitting component and a shaft that is adapted to transmit rotary power between the first and second power transmitting components, the method comprising: identifying a first frequency associated with vibration transmitted from the first power transmitting component to the shaft; identifying a second frequency associated with vibration transmitted from the second power transmitting component to the shaft, the second frequency being different from the first frequency; and coupling a damper to the shaft, the damper including a hub, a first mass, a second mass, a first resilient coupling, and a second resilient coupling, the first mass being disposed concentrically about the hub, the second mass being disposed concentrically about the hub and the first mass, the first resilient coupling resiliently coupling the first mass to the hub, the second resilient coupling resiliently coupling the second mass directly to the first mass; wherein the first mass and the first resilient coupling are configured to attenuate vibration at a higher one of the first and second frequencies and wherein the second mass and the second resilient coupling are configured to attenuate vibration at a lower one of the first and second frequencies.