Patent ID: 6543634
Filing Date: 2003-04-08
Classification: B65D

Abstract:
A plastic screw cap for sealing a container having a threaded finish and a collar adjacent to said threaded finish, said cap comprising a cylindrical cup provided with an internal thread; a rim; a pilferproof ring, with a plurality of bridges for connecting to the rim of the cylindrical cup said pilferproof ring, said plurality of bridges forming a circular fracture line, said pilferproof ring comprising a cylindrical wall having a first cross-sectional thickness such as to be substantially flexible in a radial expansion direction, a first upper rim which is connected to said rim of said cylindrical cup through said bridges, and a second opposite lower rim connected through a connection region to an internal annular bead with an inside diameter being smaller than an inside diameter of said cylindrical wall, said annular bead having a second cross-sectional thickness being significantly greater than the first thickness of said cylindrical wall; and wherein said ring further comprises: a plurality of flaps that protrude from said connection region connecting said flexible cylindrical wall and said internal annular bead, said flaps being inclined upwardly and having a third cross-sectional thickness being such as to impart to the flaps a rigidity such as to withstand, without flexing, radial stresses; and intermediate sectors for separating said flaps, said intermediate sectors having a cross-sectional thickness bigger than the first thickness of the flexible wall and smaller than the second thickness of said bead so that during inserting and removal of the cap the flaps abut on said collar without flexing, whereby to produce flexing of said ring only at the connection region where said flaps protrude.