[Stephen]

very easy to open this Regelstein Schrammelharmonika:
http://schrammelharmonika.nonfoodfactory.org/graph/IMG_0407.JPG

Can be opened by a simple switch with a finger
Could be used in vibrandoneons, melodicas, …
No screw drivers would be needed anymore to open the instrument.

There was no air loss in these Schrammelharmonikas if it was a good construction