Plastic cap

Claim 1

A molded plastic cap for use with a bottle having a neck carrying an outwardly extending thread and having an outwardly extending shoulder beneath said thread, said cap comprising a top wall, an annular sidewall extending down from said top wall and having an inwardly extending thread for cooperation with said neck thread, and an integral antitamper skirt below said side wall and connected thereto, said skirt having at least a lower portion which, when the cap is fully screwed onto said neck, is at a level below said shoulder, said skirt having also a plurality of circumferentially spaced integral inwardly projecting flaps which are integrally hinged thereto and which as molded project inwardly, the construction and arrangement being such that (a) when during the operation of screwing said cap onto said neck, said cap moves downward, said flaps are engaged by said shoulder and pushed outward thereby and then, on further downward movement of said cap during said operation, said flaps are moved past said shoulder and (b) when, during the operation of unscrewing said cap from said neck, said cap moves upward, said flaps engage the lower part of said shoulder and are forced by said engagement downward and outward into abutting relationship with said lower portion of said skirt so that the presence of said flaps decreases the effective internal diameter of said lower portion of said skirt so as to prevent said skirt, while intact, from passing up over said shoulder.