Dear fellow mechanical music lovers,  All mechanical musical
instruments have some kind of key frame.  In those controlled by
negative air pressure this key frame has only one side: the tracker
bar.  In all keyed instruments, and the keyless types working on
positive air pressure, the key frame has a device which presses the
music sheet onto the surface of the key frame in order to prevent
the music sheet from rising.

My question: How is such a device called in several languages?
For the Dutch language I can only think of the term "hemeltje"
(little heaven, because it is on top).

Hans van Oost, Netherlands

 [ Ref.: http://www.onlinewoerterbuecher.de/entry_12400.html
 [       http://www.onlinewoerterbuecher.de/entry_12500.html
 [   Drückblech {n}	pressure sheet
 [   Druckrolle {f}	thrust roller [pressure roller]
 [   Druckstange {f}	pressure rod
 [   Druckscheibe {f}	pressure disc
 [ -- Robbie