Closures for containers

Claim 2

A closure blank for application to a screw-threaded bottle by a thread rolling operation wherein the bottle has a cylindrical seal surface above the threads, said blank comprising a single piece cup-shaped metal shell having a top and a skirt, joined together at and continuous with a radiused corner, formed with an outwardly directed bead at its lower margin; and a layer of gasket material bonded to the inner surface of the top and extending around said radiused corner to form an annular seal the invention comprising said shell being formed with an upper band of outwardly pressed knurling at the upper margin of the skirt adjacent said radiused corner radially outwardly of and overlapping at least in part said annular seal and a lower band of knurling in said bead, said outwardly pressed knurling having outwardly extending ribs and the metal therebetween having a diameter approximating that of the lower portion of said skirt the positioning of said annular seal radially inwardly of said outwardly pressed knurling and the knurling on the lower bead permitting material economy by permitting minimum overall closure height consistant with forming a side seal between said gasket material and the cylindrical sealing surface of the bottle while also providing sufficient purchase to allow removal of said closure from the bottle by hand.

Claim 3

A closure blank according to claim 1 further characterised in that the upper band of knurling extends up to the radiused corner joining the top to the skirt.

Claim 4

A closure blank according to claim 1 further characterised in that the vertical extent of the upper band of knurling is about 2 mms.

Claim 5

The combination of a closure thread rolled on a bottle which has an externally threaded neck and a cylindrical sealing surface above the upper limit of the thread and the mouth of the bottle, the closure cap comprising a single piece metal shell having a top and a skirt joined at a radiused corner with an outwardly turned bead at its lower margin; and a layer of gasket material bonded to the inner surface of said shell at least extending around said radiused corner and on the adjoining cylindrical skirt, the invention comprising the closure skirt having a reduced diameter portion lying outwardly of said cylindrical sealing surface radially compressing said gasket material against said sealing surface to form an annular seal, a threaded portion lying immediately above said bead and a narrow upper band of outwardly pressed knurling lying radially outwardly of and overlapping at least in part said annular seal of gasket material between said threaded portion and said reduced diameter portion, the positioning of said annular seal radially inwardly of said outwardly pressed knurling and the knurling on the lower bead permitting material economy by permitting minimum overall closure height consistent with forming a side seal between said gasket material and the cylindrical sealing surface of the bottle while also providing sufficient purchase to allow removal of said closure from the bottle by hand.

Claim 6

The combination of a closure thread rolled on a bottle which has an externally threaded neck and a cylindrical sealing surface above the upper limit of the thread and the mouth of the bottle, the closure cap comprising a single piece metal shell having a top and a skirt joined at a radiused corner with an outwardly turned bead at its lower margin; and a layer of gasket material bonded to the inner surface of said shell at least extending around said radiused corner and on the adjoining cylindrical skirt, the invention comprising the closure skirt having a reduced diameter portion lying outwardly of said cylindrical sealing surface radially compressing said gasket material against said sealing surface to form an annular seal, a threaded portion lying immediately above said bead and a narrow upper band of outwardly pressed knurling lying radially outwardly of and overlapping at least in part said annular seal of gasket material between said threaded portion and said reduced diameter portion, the positioning of said annular seal radially inwardly of said outwardly pressed knurling and the knurling on the lower bead permitting material economy by permitting minimum overall closure height consistent with forming a side seal between said gasket material and the cylindrical sealing surface of the bottle while also providing sufficient purchase to allow removal of said closure from the bottle by hand.