A reap-binder group (10) for agricultural machines comprising at least a drive shaft (12) of at least a forked element (13), the drive shaft (12) being connected at a first end to the at least one forked element (13) and at a second end to driving gears (14) of the drive shaft (12) placed inside a containment carter (15), being provided with dust-tight means placed at the passage hole of the at least one drive shaft (12) in the containment carter (15), in which the dust-tight means comprise in succession at least a blocking barrier element for the dust and at least an accumulating and trapping chamber for the dust penetrated beyond the at least one barrier element.
