Hammer assist spring ?

[Stéphane Collin]

Hé Ric.

This long existed.

Picture attached.

Just that the spring makes the touch feel lighter at the beginning of  
the key movement, but spring action gets weaker as the key travel goes  
down the dip.  Anyway, this beast does her job fairly well.  On some  
aspects, even better than the Erard pattent.

Stéphane.

[Picture at:]

https://www.moypiano.com/ptg/files/attachments/c8/b1/a3/c8/ 
Bechstein1871actionillustration.jpg

[Alternate URL:]

http://tinyurl.com/dop6