Sometime back someone posted about a player pump where the bellows
are on the outside of the box.  At the time I thought, "That sounds
familiar..."

Well, it should, as the rotary pump in my Cable Euphona Recordo
upright pump is made that way too.  In my piano, the motor is on
the right side, mounded to the bottom board, and has a belt running
to a wooden pulley about the middle of the piano, on a rod swiveling
on the bottom board.

This pulley has a smaller pulley on it, and this is belted to the
large pulley on the pump, which is mounted on the left side of the
piano on a wooden frame via metal bars radiating from the pump box,
so the bellows are free to move on all sides.  There is a vacuum
tightened wooden idler pulley on the last belt.

All this is designed to fit behind the foot pumping bellows system
(yes, you can play either by foot pumping or by electric motor).
When things go awry with the belts, it's a lot of fun to get to them
-- _not!_ :)  The design is actually very clever, fitting all this
stuff in the space available.  The Recordo "venting" box is mounted
on the right side of the piano itself, above the motor.

David Dewey

 [ http://www.mmdigest.com/Attachments/16/05/01/160501_181525_Belt_Tensioner.jpg 
 [ http://www.mmdigest.com/Attachments/16/05/01/160501_181525_Drive_belts.jpg 
 [ http://www.mmdigest.com/Attachments/16/05/01/160501_181525_Motor_Brushes.jpg 
 [ http://www.mmdigest.com/Attachments/16/05/01/160501_181525_Under_Keybed.jpg