A lever device (LD) fits between a flow valve (FV) (7) and an adjusting unit (AU) (1) to shift a movement for the AU into a movement for the FV. The LD has a slide rod (3) and a shaft (6). The FV and a first lever (5) interlink rigidly via the shaft. The LD also has a second lever (14) and a multi-lever-armed baffle plate (10) with three knuckle-joint axles (11-13).
