If you know what the parts look like, maybe you can craft some and get it somewhat working?
One is a piece of metal wire, the other a sort of pulley to fasten the wire in and which winds the spring for the shutter blind. But remember, the wire has to pass through two eyelets that is fixed to the underside of the top plate, you can imagine how easy that is to get in place and adjust. There are stories about people who have tried to fix one of these cameras and in the end getting so frustrated that they threw it out of a window!
Seeing Aksel's Flexarets reminds me that I have a nonfunctional Flexaret IV sitting on a shelf, I'd rather try to resurrect that one.
Leonore, that Contaflex looks gorgeous (I admit to being a Contax fan!), hope you get a lot of fun with that!