Plastic screw cap with tamper-evident ring

A plastic screw cap comprising a cylindrical cup provided with an internal thread and with a tamper-evident ring which is coupled to the rim of the cup by means of a plurality of bridges forming a fracture line, said ring having a retention means for retaining it below an annular raised portion of a container whereto the cap is applied, incisions being formed by means of a cutting machine provided with a blade on the outside of said tamper-evident ring, said incisions being configured such as not to cross the entire thickness of the ring and to allow an outwardly directed elastic radial expansion of the ring with a simultaneous inwardly directed bending of the bottom of the ring such as to permit the ring to pass beyond said annular raised portion during the application of the cap to the container, said incisions comprising axial incisions, which are distributed circumferentially on the outside of said tamper-evident ring, and a circumferential incision which extends on an outer face of said tamper-evident ring circumferentially between the fracture line and the free rim of the tamper-evident ring.