Closing device assembly (10) for systems for milking animals, provided with at least one primary passage (14) and at least two secondary passages (16a-c), wherein the primary and secondary passages are provided with first (80) and second (93a-c) connecting edges, respectively, with respective openings each having an axis, further provided with at least one closing device (15a-d) for at least one unused, non-selected secondary passage, which closing device is provided with a closing edge (84a-d), wherein of each set of connecting edges and closing edges to be connected to each other in each case at least one is provided with a seal (94a-c), wherein the closing device assembly further comprises first drive means (51a,b) for mutual displacement of the first connecting edge and the second connecting edge of a selected secondary passage from an uncoupled position in which the axes (S,T) of their openings are not in line with each other to a position in which the axes of their openings are in line, a coupling line, with each other, and second drive means (60a,b) for bringing said connecting edges against each other.
