Mould for forming tamper evident closure caps

摘要

The invention provides a mould for use in the injection moulding of a closure (10) from a synthetic plastics material. Such a closure (10) is suitable for a container having an externally screw-threaded neck and comprising a top (15) and a depending skirt (16) which has on its internal surface a screw-thread complementary to the screw-thread on the container. A free edge of the depending skirt is joined by a plurality of frangible bridges (13) to a tamper-evident band (11) which comprises a generally cylindrical body portion and a continuous or segmented rib (18). The rib extends inwardly of the body portion and is adapted to provide a lip to engage under a retaining flange extending outwardly from the neck of the container below the screw-thread thereon. The rib (18) has an upper side facing generally towards the top of the closure and an under side facing generally away from the top. The mould defines the upper side of the rib (18) as comprising a first surface contiguous with the body portion of the band, which surface slopes inwardly and downwardly from the top portion (15), and a second surface which is positioned radially inwardly from the first surface, the second surface having a slope angle more nearly normal to the longitudinal axis of the closure than the first surface is to that longitudinal axis. The mould is capable of being operated at extremely high rates to produce closures with improved resistance to removal from the container. <IMAGE>