One-piece cap for liquid dispenser container

In a one-piece cap for closing a liquid container of the type intended to be installed for supply purpose in upside down position onto a liquid dispenser, said container having a neck on which said cap is sealingly mounted and through which a liquid supply tube passes when the container is installed onto the dispenser, said cap comprising:

• a lid having a surface area substantially identical to the one of the neck;
• and
• a skirt integrally projecting from said lid;
• said skirt having an internal face on which gripping means are provided for sealing the liquid container neck;
• said lid being provided with a central recess including a tubular guiding portion projecting from the lid in the same direction as the skirt, said guiding portion being sized and positioned to receive said supply tube, said central recess also including a bottom portion,
• the improvement wherein said bottom portion is in the form of a cone that projects from the guiding portion, said cone being provided with a number of frangible lines extending within meridian planes in such a manner so as to allow splitting of said cone into a corresponding number of petal-shaped segments when the container is installed onto the dispenser and its cap and neck are penetrated by said supply tube.