US Patent 8627968 Screw cap for containers for liquids

A screw cap (10) for containers for liquids, comprising a first capsule (11), which is internally provided with a thread (12) and is to be screwed onto a corresponding complementary thread (13) of a neck of a bottle (14), and a second capsule (15), which surrounds said first capsule (11) and is designed to rise axially away from the first capsule (11) upon first unscrewing, by means of spacing means that act at the first rotation of the second capsule (15) with respect to the first capsule (11), means being provided for the irreversible locking of said second capsule (15) in the raised configuration relative to said first capsule (11).