Device for closing a container by screwing, secured by a retractable lug

A closure device for a tank-forming container, of the type comprising:

• a coupling member comprising an outer threading and intended to be borne by the container,
• a cap comprising an inner threading and intended to be fitted onto the coupling member or to be removed from this coupling member by screwing or unscrewing,
• safety features comprising:
• at least one circumferential locking abutment borne by the cap, and
• at least one retractable complementary circumferential locking abutment borne by the coupling member,
• characterized in that the coupling member comprises:
• a body of generally annular form,
• a radial arm provided with a free end and a linking end with the body, the free end of the radial arm being able to be displaced according to at least one axial component by elastic deformation of this radial arm,
• a radial forearm provided with a free end and a linking end with the free end of the radial arm such that the radial forearm and the radial arm each extend from their linking end to their free end in opposite directions,
• a lug borne by the radial forearm,
• this lug forming the retractable complementary circumferential locking abutment,
• wherein the lug extends axially from the radial forearm in a direction opposite to that of the axial displacement of the cap when it is screwed onto the coupling member;
• wherein the radial forearm extends mainly radially from its linking end to its free end;
• and
• in which the cap comprises an edge delimiting an open end of said cap, said edge being delimited by an outline forming an outer cam profile of said cap configured to cooperate, during the screwing or the unscrewing of the cap, with the lug to displace or hold in its retracted position the retractable complementary circumferential locking abutment borne by the coupling member.