US Patent 6854614 Closure having an improved thread design

A closure for use on a container having an externally threaded neck is disclosed wherein an inner surface of a downwardly depending skirt portion of the closure cap includes a helical thread having a flat upper surface with a lower thread profile having a first depth greater than an upper thread profile of a second depth. The helical thread of the closure tapers into the sidewalk of the closure skirt. The closure is provided with a seal integral with the inner surface of the skirt, spaced from a top wall of the closure, and retained at a lowermost point along the downwardly depending skirt by a bead.