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US 4,674,649 AGranted
Metal can end with plastics closure
AssigneeMetal Box Limited
InventorAndrew P. Pavely
Life of this patent
Estimating the term…
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AssigneeMetal Box Limited
InventorAndrew P. Pavely
Estimating the term…
A metal can end with a tear-open plastics closure in which the closure has a plug part fitting into an aperture in the can end, a rim surrounding the plug part, and a pull tab, wherein a groove extends across the plug part and aligned grooves or interruptions extend across the rim to provide a hinge line allowing the tab and the adjacent portion of the plug part to pivot upwardly to provide venting of the can in a first stage of opening before full opening of the closure in a second stage. The closure is of the kind which is moulded on to the can end so as to totally enclose a downturned flange around the periphery of the aperture, and to be capable of being sheared against the flange on opening, and the residual thickness of the plastics material below the flange is greater in the main portion than in the vent portion of the closure to provide a temporary arrest after venting. The plug part is stiffer than the metal of the can end so that doming of the can end under internal pressure is concentrated in the metal and the pull tab extends at an angle to the can end surface, rendering it easier to grasp for opening the aperture. A second hinge line may be provided at the far end of the closure, with a further increase in residual thickness, so that the closure can be retained on the can end while being hinged out of the way for pouring.
A metal can end with an aperture surrounded by a downturned flange formed in the metal of the can end and closed by a tear-open plastics closure, said closure having a plug part fitting into the aperture, a rim surrounding the plug part and overlying the metal of the can end around the aperture, and a laterally extending tab moulded as an integral part of the closure, the closure being moulded on to the can end so as to enclose the flange totally but to be capable of being opened by being sheared against the flange when the tab is pulled up, wherein the closure is formed with a groove extending across the plug part of the closure transversely to the length of the tab so as to form a hinge line allowing the tab and the adjacent portion of the plug part to pivot upwardly in relation to the remainder of the plug part, and the rim is reduced in thickness or interrupted in line with the groove so as not to afford substantial resistance to the hinging action, thus permitting venting of the can before full opening of the closure, and wherein the residual thickness of the plastics material below the flange is greater in the portion of the closure on the far side of the hinge line from the tab than in the portion adjacent to the tab, so as to cause a temporary arrest in the shearing action to allow time for venting before full opening of the closure.
Dependencies are inferred from the claim text.