Mechanism for a conveyor supporting arm and a conveyor supporting arm comprising such a mechanism

The mechanism has a double acting jack (23) with a body (25) and a drive shaft (27). A connecting rod (29) has one end pivotably mounted on the drive shaft and another end pivotably mounted on a support arm of a conveyor. A connecting rod (31) has one end pivotably mounted on the drive shaft and another end connected pivotably to an inner ring that supports the conveyor. An independent claim is also included for a concrete mixer type vehicle.