Fred Sturm wrote: > > I guess my main question is, "Is the moi of the hammer assembly, as > perceived from the key, reduced by the engagement of the spring?" Since > the stored energy is always present, the energy required to accelerate > the hammer assembly mass from the front of the key is always reduced. So > does that, in effect, reduce the moi of the hammer assembly mass? Or how > does the spring enter into the picture in engineering terms? > Fred, I would say no, the spring does not change the MOI of the hammer or how it is felt at the fey. When the action is at rest the spring has potential energy. When the key is depressed the energy is used to help move the action. When the action returns to rest the spring is compressed and it stores the energy for latter use. I suspect the drawback of using the springs is the potential for creating undue harmonic motion in the action. With too much spring tension the action would take a wile to come to rest. There would be a lot more dance to the keys. John Hartman RPT John Hartman Pianos [link redacted at request of site owner - Jul 25, 2015] Rebuilding Steinway and Mason & Hamlin Grand Pianos Since 1979 Piano Technicians Journal Journal Illustrator/Contributing Editor [link redacted at request of site owner - Jul 25, 2015]
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