Thanks, Ric. I knew you'd done "something" with magnets but just couldn't remember exactly what. And all my Journals are at the school. BTW, I did read the article. :-) Avery At 08:00 PM 12/29/04, you wrote: >Avery Todd wrote: > >>I thought Richard did "something" along the lines of a magnetic action. >>Am I wrong? >> >>Avery > >I have a full blown origional solution to magnetic assist actions, which >employs a pair of opposing magnets on the key stick and whippen forward of >the capstan, and a pair of attracting behind the capstan. This is >different then most other assist systems in that it pits one moveing lever >against another instead of a non-moving point against one of the >levers. The whole system is described in an article published both in the >American and European journals last year for those interested. > >That said, the exact same concerns I have stated here were underlined in >that article. Assist systems should not be used to avoid dealing with >designing into an action desirable mass levels.... i.e. inertial >characteristics... i.e. dynamic touchweight. Flip side of that >postulation is that once these are designed in, the only real need for any >assist mechansisms would be to compensate for very small variances in >action ratio that are unavoidble in building any action. >Essentially, this means around 1-2 grams dead DW max, unless one is >designing purposefully an action which will be used to replace a >predetermined amount of counterbalance mass. To my knowledge, no one yet >has done any real research into the resulting dynamics of such an action. >That fact, combined with the more generalilzed fact that pianists playing >concert intruments around the world have clearly demonstrated a preference >for non assisted actions... leads me to believe replacing counterbalance >mass with assist springs is not such a good idea... at least not as has >been employed by any manufacturer up to the present. So I conclude for the >time being that any assist mechanism should only be used to even out very >small variances in static DW. One could argue that it would be better to >find the root cause of such variances (ratio problems key to key) and >solve those instead. > >fwiw... I have refined the whole concept employing a new twist on the old >rocker arm capstan to eliminate the problem of the magnet pair getting in >the way of capstan adjustments. > >Cheers >RicB > >_______________________________________________ >pianotech list info: https://www.moypiano.com/resources/#archives
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