A disposable diaper includes a top sheet, a back sheet, and a liquid absorbent core disposed therebetween. The clutch is annular and co-operates with a shaft shank, and the free end of the support leg rests against a support surface carried by the shaft shank upon rotation between the shaft shank and the clutch, the support leg is turned away, whereby the piston is displaced and opens a valve through which the hydraulic pressure is evacuated. Thus, a joint coordination between different types of diversity transmission schemes is proposed so as to achieve a significant capacity increase at a moderate complexity.