Patent ID: 7491160

Claim:
A grooved forming roll, comprising: a rotatably supported shell having an outer surface; portions of the rotatably supported shell forming a plurality of circular openings which open at least on to the outer surface of the shell; each opening defining a plurality of adjacent openings, from the plurality of circular openings; corresponding with each opening, portions of the rotatably supported shell forming a circular groove recessed from the outer surface, each circular groove arranged concentrically relative to the corresponding opening, and each circular groove defining an outer radius; wherein a portion of one of said formed circular grooves extends to each opening from each adjacent opening; wherein the outer radius of the circular grooves is selected such that a number of necks of material formed of the shell and forming part of the outer surface of said shell lie within the area of one circular groove, which necks are delimited by the adjacent openings and their corresponding circular grooves; and wherein the number of necks is greater than the number of adjacent openings of the corresponding opening.