Virtual Capstan

Richard Brekne Richard.Brekne@grieg.uib.no
Fri, 20 Jun 2003 00:35:06 +0200


---------------------- multipart/alternative attachment


Phillip Ford wrote:

>
> Hi Ric,
>
> An interesting idea.  I'm not sure that I see how the effects of this device differ from those of a whippen assist spring.
>
> Phil F
>

Hi Phil...

Andre mentioned this too. Wanted to know about the effect on UW visa vi whippen assist springs.  What I have in mind is more
or less as in the below illustration I have drawn up. This is just a rough draft so the actually magnets to be used will
probably be of somewhat different dimensions. Perhaps 5mm diameter by 10 mm long.

The whippen assist spring simply makes the whippen lighter by pulling up against it from the whippen rail. This really does
something quite different. It provides a secondary support for the weight of the action very much in the same sense that the
capstan supports the action weight. As the key moves upwards, so will the force pushing upwards from the key magnet (2)
against the whippen magnet (1). The whippen is also physically lifted by the standard capstan, so whatever force is determined
by the distance between these two magnets should remain pretty much constant through out the whole keystroke. In essence... it
functions as if the ratio is fooled into thinking its weight ratio is lower then what the standard capstan would dictate
otherwise. Nifty. It would also reduce a bit of friction at the standard capstan. Since the standard capstan does the bulk of
the lifting, the magnets dont need to be overly strong.

These can be pretty light weight yet powerful enough to make a significant difference. I'm still working on the obtainable
figures... but its encouraging enough that I decided to make this public so that any interested could start fooling around
with the general idea as well.


[Image]copy write Richard Brekne
--

I agree with your point about the friction at the knuckle. Its a good thing... in reasonable amounts.

I've been playing with the basic concept of spliting the weight and distance components of the action ratio into two seperatly
adjustable quantities for about 8 months now. Tried some pretty weird things. But the main problem has always been finding
something that didnt get in the way of regulating the standard capstan. This solves that problem.

Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html


---------------------- multipart/alternative attachment

--------------FE422B96749E314199B52ED5
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/e8/17/e4/f0/attachment.htm

--------------FE422B96749E314199B52ED5
A non-text attachment was scrubbed...
Name: C:\\DOCUME~1\\RICHAR~1\\LOCALS~1\\Temp\\nsmailSB.jpeg
Type: image/jpeg
Size: 23197 bytes
Desc: not available
Url : https://www.moypiano.com/ptg/pianotech.php/attachments/c5/99/4d/91/nsmailSB.jpeg

--------------FE422B96749E314199B52ED5--

---------------------- multipart/alternative attachment--


This PTG archive page provided courtesy of Moy Piano Service, LLC