Method and apparatus for making shells for cans

摘要

The disclosure relates to method and tools for making shells used in the manufacture of can ends. A first set of tools makes blank pre-forms having a substantially flat central panel and an upward-extending chuckwall about the edge of the panel. The junction area between the panel and the chuckwall has a relatively large radius of curvature at this time. A second set of tools forms on the blanks a lip extending outward from the upper end of the chuckwall and generally parallel to said panel; then the panel and the chuckwall are separately gripped, followed by relative movement between the panel and the chuckwall while wrapping the junction area around a forming punch to form a panel wall in the junction area extending upward from the inner part of the chuckwall. Then the lip is formed into a curl edge section which ends in an inner curl diameter that is round and concentric with the chuckwall. Methods and apparatus are disclosed for (a) separating the pre-forms at the first tools and then transferring them individually to the second tools, or (b) partially separating the pre-forms at the first tools and using the advancing sheet metal stock to carry the pre-forms to the second tools. Also disclosed are various tool layout modifications for use in different types of single acting or double acting reciprocating presses.