Perforating cap, particularly for a flexible tube

An assembly for closing a tube, said assembly comprising:

• a tube head comprising a neck and a closure liner sealing said neck;
• a cap comprising a punch adapted to cut said closure liner, said neck and said cap being configured to allow said cap to be fixedly held on said neck in a first standby position in which the punch is held at a distance from the closure liner, and in a second position of use in which said punch perforates said closure liner, said neck comprising at least one guide groove configured to cooperate with said cap to allow a rotational movement and/or an axial movement in order to transition said cap from the standby position to the position of use and/or from the position of use to the closed position, said groove comprising successive guide portions including a first portion vertical relative to the axis determining the standby position, followed by a second portion which is helical with a pitch x and allowing the cap to depart from the standby position, then followed by a third portion which is helical with a pitch y and allowing the cap to transition to the position of use, then followed by a final portion which is horizontal relative to the axis and allowing the cap to transition to the closed position, the pitch of the third helical portion being greater than the pitch x of the second helical portion.