Method of making an inwardly directed projection on a plastic container

摘要

A thin-walled, cup shaped container molded of polypropylene, or other suitable material, is formed with a tamper-evident band initially positioned outside the lip at the top of the container wall. The lower edge of the band is connected to the container by spaced frangible bridges. A lid closes off the top of the container and has an outer and inner skirt respectively fitting outside and inside the container lip. The upper end of the band is formed into an annular inward projection overlying the periphery of the lid. Forming the retainer projection is accomplished by bringing a heated tool in contact with the band to heat the same until near its melting temperature. The tool has slanted walls converging at a radius and shaped to bend the projection approximately horizontally inward. The lid cannot be removed without tearing off the band.