. . . . "Below the invention will be further elucidated on the basis of two exemplary embodiments shown in the attached drawings, in which: FIG. 1 is a device according to the invention arranged under a cow; FIG. 2A and 2B show cross-sections in isometric view of a first embodiment of a coupling piece according to the invention, in the milking position and in the cleansing position, respectively; and FIGS." .