Automatically closing stopper for dispensing liquids from deformable containers

An automatically closing stopper for dispensing liquids from deformable containers, comprising a profiled body sealedly applicable to the mouth of a container and having a hole for housing a valve, wherein said valve is formed in one piece of deformable moulded material, is of elongate form and comprises an annular body and at least four separate flexible appendices projecting from the same side of the annular body and having one end free and their other end or base rigid with the annular body, those sides of each appendix which face the sides of the appendices adjacent to it being defined by smooth surfaces which are substantially specular to each other and sealedly rest against each other when the valve is closed, said hole in the profiled body being bounded by an annular wall which interferes with the outer surfaces of said appendices in correspondence with their bases, to urge their smooth surfaces against each other and form a seal between them, so closing said valve when in its rest state wherein from each appendix there outwardly projects a longitudinal rib, a cover being provided to be superposed on said appendices to interfere with their longitudinal ribs and press the smooth surfaces of the appendices against each other to provide sealed mechanical closure of the valve.