Virtual Ribs, A new crown support method

[David Love]

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Why would this be better than simply creating a rib crowned and
supported panel that can be compressed to the requisite stiffness
through the use of downbearing without overstressing the panel?
=20
David Love
davidlovepianos@comcast.net=20
-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Erwinspiano@aol.com
Sent: Monday, April 11, 2005 6:34 PM
To: pianotech@ptg.org
Subject: Re: Virtual Ribs, A new crown support method
=20
  RIc
  May the force? be with you brother.grin
  Dale
Hi folks

After a few months of experimenting, I am ready to announce a new (I=20
believe)  method of supporting crown for any type of soundboard. The=20
method allows for both restoring crown and supporting it in older=20
panels, and designing new panels in which the concerns of mass levels=20
and degree of assembly stiffness can be to a far greater degree treated=20
independantly.=20

In essence, an array of repelling high power neodym magnets of=20
appropriate dimmensions and strengths are used to support crown against=20
downbearing from the strings. One set are imbeded in soundboard button=20
similar wooden sheaths and are attached to the soundboard with glue and=20
screws.  Opposing these is another set which are mounted into a very=20
strong wooden beam such that their distance from the soundboard attached

magnets can be adjusted easily from below.  One can either choose to=20
simply provide support directly under the bridge, or without too much=20
difficulty, contrive what amounts to a system of virtual ribs with fully

adjustable support for crown.

For edification... Neodym magnets that measure 30 mm =D8 by 5 mm thick =
can

hold / push approximately 25 kilos.  Since there is no phsyical=20
connection between the soundboard and opposing magnets, the assembly is=20
not directly mass loaded. Hence stiffness and crown support is provided=20
without mass loading.

More later on as I formalize an article on a working example I am hoping

to finish soon.

As is my habit... this is an open source idea, I encourage any and all=20
to take up and refine it in their own fashion.  My own initial results=20
indicate that the principle is very successful.

Cheers
Richard Brekne
=20

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