Abstract: A movable abutment plate (28) which is bound by common vertical guide to a vertical axis, an axially hollow turntable (9) carrying two sets of vertical dosing devices (V1V2) and a central cap-shaped screw (29) secured to the top end of bar (33) are provided. Bar (33) passes through the turntable (9) and turret (1), such that the bar extends into the lower part of the dosing machine, where the bar (33) includes a crown gear (36) with suitably shaped peripheral apertures (37) arranged in an equispaced relation. When turntable (9) is lowered, one of the apertures (37) in crown gear (36) engages with a crankpin (41) which is fitted on the slowly rotating shaft of geared motor (43) controlled by encoder (44). When the volume of dosing devices (V1, V2) needs adjustment, turntable (9) is temporarily lowered and geared motor (43) is actuated to thereby lift or lower plate (28), against which bear the lateral appendices (25) of the moving elements of the dosing devices (V1, V2).