The Stolle Corporation

Philip J Spangler

Carl F McEldowney

Wayne A Spoltman

A sheet metal end closure for a container of pressurized products, which closure includes a substantially planar central panel, a countersink around the central panel, a chuckwall around the countersink and a seaming flange around the chuckwall. It further includes an annular downwardly stepped portion between the central panel and the countersink and a coined zone in the panel radius which connects the stepped portion to the countersink. The invention includes a method and apparatus for forming such a sheet metal closure wherein the panel radius between the central panel and the countersink is coined around at least a portion of the circumference of the central panel before the periphery of the central panel is reformed. In accordance with this invention, a major portion of the central panel is moved away from the countersink by depressing the outer peripheral portion of the central panel along with the countersink and chuckwall. Depressing the peripheral portions of the end shell with respect to the central panel increases substantially the height of the central panel and uses the slack or loose metal created by the coining operation. This puts the metal in the end shell substantially into tension and helps reduce, or eliminates, central doming of the end shell due to internal pressure in a container on which the shell is seamed.

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Sidney, OH, United States of America

Philip J Spangler