Action Ratio, was: More off the wall stuff

[Isaac OLEG]

Dear Richard,

Do you mean distance leverage and force leverage are suppose to change
the same at the same time ?

and that the only difference that we can find between the 2 is induced
by friction change or mass distribution change ?

Confusion is that lever laws apply to levers (fixed lengths) and  tell
us about force direction.

The lever's lengths is changing at the whippen/capstan, depending of
the configuration.

The contact line between the parts in the piano  action is a tangent
following a path, the leverage is changing accordingly of the change
of the lever's length during the travel.

Indeed David's method of measuring is not totally static, as geometry
method is, because it takes in account the result of these different
levers, that is what I wanted to say.

That is how I understand it anyway, does not mean we can't use any of
the above methods...

Let's take a piano key, for instance, a very slight change in it's
attack angle change its leverage enough to be noticed by a change in
DW even if the leverage is only better at the beginning at the stroke.


Cheers yourself , and take care of the !!!!!!!

Isaac OLEG

Entretien et reparation de pianos.

PianoTech
17 rue de Choisy
94400 VITRY sur SEINE
FRANCE
tel : 033 01 47 18 06 98
fax : 033 01 47 18 06 90
cell: 06 60 42 58 77

> -----Message d'origine-----
> De : Richard Brekne [mailto:Richard.Brekne@grieg.uib.no]
> Envoye : dimanche 19 janvier 2003 13:45
> A : oleg-i@wanadoo.fr; Pianotech
> Objet : Re: Action Ratio, was: More off the wall stuff
>
>
> Where does all this mystery come from  ?
>
> Davids formula is just another way of applying the law of
> leverages. Its
> easy enough to factor out the weight components of the equation and
> arrive at a more simple and straightforward equality for the action
> ratio. This is, and can never be anything else then the
> product of the
> ratios of the three levers.
>
> There has to be consistancy between weight, distance, and speed in a
> levers ratio. Whatever the ratio of any given lever is, its
> has the same
> effect on these three. This is basic to the law of levers.
>
> Any ratio that results in something else has simply got to
> be a measure
> of something else. Could be a valuable something else in another
> context, but just so..
>
> Cheers
>
> RicB
>
>
> Isaac OLEG wrote:
>
> > Terry,
> >
> > The drawback of this method is that the leverage is
> changing  during
> > the stroke (more or less depending of the action setup, kind of
> > whippen, etc...
> >
> > At this moment seems to me that only David's method gives
> an evened
> > appreciation of what goes on for all the stroke.
> >
> > Regards
> >
> > Isaac OLEG
> >
>
> --
> Richard Brekne
> RPT, N.P.T.F.
> UiB, Bergen, Norway
> mailto:rbrekne@broadpark.no
> http://home.broadpark.no/~rbrekne/ricmain.html
>
>
>