Abstract: A machine having a belt conveyor (10) and the support structure (16) of which acts on a balance (4) arranged to measure the weight of objects (2) in transit on the conveyor (10); a geared motor unit (40) provided to supply the required rotary motion to the drive roller (12) of the conveyor (10), said geared motor unit (40) being positioned spaced from and to the side of the conveyor (10) and being supported, with the axis of its shaft (44) in a fixed position substantially parallel to the axis of the roller (12), by a fixed structure (5) which does not act on the balance (4) wherein between the shaft (44) of the geared motor unit and the shaft (14) of the drive roller (12) there is provided mechanical members arranged to transmit motion and to allow relative movement between the axis of the shaft (44) and the axis of the shaft (14).