Sustain pedal lift ratio

[RicB]

Hi Ron.

Thanks for the informational post.  Definantly a keeper.  This paragraph 
caught my eye and prompted the following querry.  As with all lever 
systems there are three leverage concerns yes ??  Lift ratio, speed 
ratio, and weight ratio.  Now I havent really thought about the pedals 
with these in mind before so I'm out fishing as it were.  But it would 
seem to me that perhaps all three would be worth taking into 
consideration.  Speed ratio gets into the control a pianist feels in the 
action... and I would assume the same (in principle) holds true here.  
Weight ratio would come into play if the the weight being lifted was 
more then appropriate for the leverage.  And then there are these points 
you sketch relative to the distance ratio. 

What I'm wondering is how much thought has gone into the pedal / 
trapwork design with all these in mind. Any thoughts you (or anyone 
else) might have would be welcome.
Cheers
RicB


    The lift ratio and the resistance of the pedal system are two
    separate issues, regarding the performance of the sustain pedal. Most
    manufacturers fit a return spring to the damper lift tray, the
    sustain lever directly under the keybed, or both. The return spring
    on the damper lift tray can create problems over the longer term,
    since its not usually possible to position the spring directly over
    the push rod. When the return spring is offset from the push rod, the
    damper lift tray can develop a compression-set warp over a number of
    decades. This is a long term problem which won't usually occur while
    those who built the piano are alive. Eventually, once the builders
    are lying quietly in a box on a hillside somewhere, some repair tech
    in a workshop might be found whining about another case of poor
    design staring them in the face, as they deal with a warped damper
    lift tray.

    snip...
    Ron Overs