Virtual Ribs, A new crown support method

[David Love]

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I=92m not sure I understand the concept which means that it must not =
work,
right:-)?  The RC&S designers seem to be doing a pretty good job of
control.  That plus the installation of vertical hitches and an
adjustable plate mounting system allows a lot of fine tuning.  Also, it
seems to actually work, whoa!
=20
David Love
davidlovepianos@comcast.net=20
-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Thomas Cole
Sent: Monday, April 11, 2005 9:53 PM
To: Pianotech
Subject: Re: Virtual Ribs, A new crown support method
=20
Adjustability comes to mind. You can come only so close to the optimum
amount of stiffness in the different areas of the board when choosing
panel and rib materials and dimensions, and that stiffness may change as
the panel ages. So magnets would allow for a fine tuning, no?

Tom Cole

David Love wrote:


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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