Bottle closure and finish

Abstract

A plastic closure having inner pressure sealing skirt and outer finish engaging skirt has a plurality of fingers evenly spaced around the inner side of the outer skirt. The corresponding finish has a like plurality of indentations evenly spaced around its circumference for engagement by the fingers when the cap is applied. The indentations may be in the form of recesses spaced from the bottle mouth, having a horizontal lip at the top edge, and having a side wall smoothly merging with the outer surface of the finish at the side of the recess. Alternatively, the recess may be a bayonet groove spiraling downwardly on the finish and then bending into a horizontal or upwardly spiraling groove for locking the fingers in place against pressure in the bottle. Another embodiment would employ a groove spiraling downwardly on the finish at a first depth, and then terminating in a groove portion of a second greater depth. The latter finish cooperates with a closure finger structure having a base of similar thickness to the first depth of the groove, and a boss on the base is adapted to enter the deeper groove portion and accordingly is of correspondingly greater thickness. The inner skirt of the closure forms an improved seal when its outer face is cylindrical or frusto-conical in an outward and downward flare, and the finish has a frusto-conical, downwardly converging camming surface immediately within the bottle mouth.