Method and apparatus for triple roll seaming end closures to container bodies

A method of triple roll seaming flanged sheet material end closures to a flanged sheet material container body, comprising, in any order, both introducing the end closure into an open end of the container body and deforming the end closure flange alone before rolling both flanges together radially inwardly around each other until a triple rolled seam is obtained including more than five layers of container body and end closure sheet material;

• wherein the improved step of deforming the end closure flange alone comprises:
• raising the peripheral portion of the flanged end closure into a frustoconical portion at a predetermined angle, and forming a first small radiused rolled section at the free end of the end closure flange so that upon the completion of said improved deformation step the small radiused rolled section is disposed at the outer end of the completed frustoconical portion.

Apparatus for triple roll seaming flanged sheet material end closures to a flanged sheet material container body, comprising means for holding the end closure for rotation about its axis, a first phase tool setup including displaceable forming tool means comprising means for raising a frustoconical portion in the peripheral region of the end closure flange at a predetermined angle relative to the yet undeformed rest of the end closure flange and means for forming a first small radiused rolled section at the free end of the flanged end closure, said means for raising a frustoconical portion and said means for forming a first small radiused rolled section cooperating so that before a second phase seaming tool setup is brought into position the small radiused rolled section is disposed at the outer periphery of the frustoconical portion;

• and the second phase seaming tool setup including radially displaceable seaming tool means for rolling the flanges together radially inwardly around each other until a triple rolled seam is obtained including more than five layers of end closure and container body sheet material.

A method of triple roll seaming flanged sheet material end closures to a flanged sheet material container body in which, before rolling both flanges together, the end closure is received in an open end of the container body and the end closure is deformed alone;

• wherein the improved deformation step comprises raising a frustoconical portion in the peripheral portion of the end closure flange to a predetermined angle with respect to the yet undeformed part of the end closure flange so as to form an inflection line therebetween, and forming an initial, small radiused rolled section at the free end of the frustoconical portion so that upon completion of the improved deformation step and after the end closure is received in the open end of the container body, the outer edge of the rolled section is directed toward the yet-undeformed container flange and the yet-undeformed container end flange overlies the yet-undeformed part of the end closure flange substantially up to the zone of inflection which defines a line of articulation for further deformation of the peripheral portion of the end closure flange, and then rolling the flanges radially inwardly together around each other until a triple rolled seam is obtained including more than five layers of container body and end closure sheet material.