The oscillating mounting type AB-D is the "Price Breaker" among the freely oscillating mountings from ROSTA. The pantograph-like construction of the two parallel rubber suspension units gives the AB-D oscillation characteristics similiar to the types AB and AB TWIN. Because of the significantly shorter lever connections (in the double rubber suspension unit), the AB-D offers a much higher loading capacity than the AB for the same compact design. The linear spring deflection under load is still sufficient to assure for this oscillating unit the respectably low natural frequency of ca. 3.2 Hz. At a vibrator or wave frequency of ca. 16 Hz, this is sufficient for a high insulation efficiency of ca. 95%. As with all screening machine mountings from ROSTA, the characteristic of the AB-D assists the linear oscillation motion of the screen. No lateral guides are necessary for passing through resonance in a controlled manner; the mounting is laterally stable. This low-cost oscillating unit offers sufficient insulation for all plants that are not mounted on high screen platforms or steel structures "above ground".
The units are mounted by directly bolting the steel supports to screen and support structure.
The housings of the double rubber suspension units are of alumium profile for sizes
AB-D 18 to AB-D 45, and in spheroidal graphite iron for the three sizes AB-D 50.