Further to my previous post about Davide's dilemma with his Studio 42, I thought I'd take a look at my own Olivetti Studio to see if I could be of help.
This tiny little spring...
...seems to provide that tension that you feel when you lift up the paper bail bar that rests against the platen when you type.
Who would have guessed?
I hope this is of some help to you, Davide.