Belt and Pulley Speed Reduction System in the
Wurlitzer Style 33 Mandolin PianOrchestra
Philipps Pianella Model Silvana-Xylophon
(Krughoff collection; Tim Westman restoration)

View of the early style belt driven crankshaft operated feeder bellows (or pump) using an intermediate speed reducing pulley. in feeder bellows produce both wind-pressure (to blow the pipework) and a vacuum (to operate the valve chests and other pneumatically motivated mechanical devices).