Bottom portion of the
Wurlitzer Style 28B Mandolin PianOrchestra
Philipps Pianella Model 28 (Victoria)
(Gilson collection, 1997)
 At bottom, the feeder bellows supply both vacuum (to operate the various mechanisms) and wind-pressure (to blow the violin pipes). A round leather belt between the motor and the large pulley operates a chain and sprocket gear type of speed reduction that rotates the pump's crankshaft. The vacuum reservoir is at the left end of the pump, while the wind-pressure reservoir is on top of the pump, its two leaf-springs visible between the reservoir top and the bottom of the support shelf above it. |
In the top half of the picture is the main valve chest, which sits on the wooden shelf just above the pump bellows. The small lead/tin alloy tubes rising vertically connect the array of individually controlled valve pouches to the holes in the tracker bar (which in turn reads the perforations in the music roll). Another set of larger tubes leading out of the top of the chest connect to the pipe chest, while on the back-side rows of motor pneumatics operate the piano action. The main stack is responsible for controlling all notes on the musical scale.
|
