Abstract: A pneumatic distributor of granular and/or powdery materials includes a main distribution duct having a first end in the region of which an air-flow is injected into the duct under pressure, and a second end. The main duct includes respective adjacent converging-diverging portions, with reference to the direction of the air-flow, defining a Venturi duct. A dosing device is provided for delivering a metered quantity of material into the main duct in the region of the narrow cross-section of the Venturi duct, for the mixing of the material into the air-flow and the entrainment of the mixture obtained towards the second end. The distributor includes at least one auxiliary duct, bypassing the Venturi duct, in order to connect a section of the main duct disposed upstream of the Venturi duct to a section of the main duct disposed downstream of the Venturi duct.

Abstract: A volumetric metering device for the metered delivery of granular and powdery materials, particularly for machines for distributing such materials. The device comprises a housing formed in one piece of plastic material, a metering member which is supported rotatably in the housing, can be handled individually, and includes a plurality of metering wheels mounted on a shaft and clamped in a group between two flanges, a selective drive-transmission interposed between the wheels and the shaft, a scraper for cleaning the wheels in motion and anchoring the idle wheels, and a feeler device which is held at a distance from the metering member with resilient preloading.

Abstract: A gearbox, particularly for transmission systems in devices for metering granular and/or materials in powder form, includes a pair of shafts, that is, a drive-input shaft and a drive-output shaft, respectively. On the output shaft is at least one pair of coaxial freewheels, on each of which an end of a respective linkage carrying a movable fulcrum device is active. The opposite end of each linkage is driven with a reciprocating oscillatory motion about the fulcrum device by way of an eccentric device provided on the drive-input shaft in order to convert the reciprocating oscillatory motion into an intermittent rotary motion of each freewheel and consequently to bring about a rotary motion of the drive-output shaft in a preselected direction of rotation.