Method and apparatus for forming container end panels

A method of forming a container end piece in a press having a fixed base and a movable platen, comprising the steps of:

• (a) blanking a workpiece;
• (b) holding said workpiece between a pressure sleeve carried by the movable platen and a die core ring fluidly supported on the base;
• (c) forming said workpiece into an inverted cup over said die core ring by advancing a punch shell carried by the movable platen;
• (d) advancing a punch core and a concentric punch core ring to reverse said inverted cup and form an end piece having a preliminary chuckwall joined to a central bottom portion by an enlarged radiused portion with said central bottom portion being supported on a die core fixed to the base with said chuckwall and chuckwall angle being formed between said punch core ring and said die core ring;
• (e) advancing said punch core until it bottoms on said die core;
• (f) shortening said chuckwall and reducing the radius of said radiused portion by continuing the advance of said pressure sleeve and said punch core ring toward said base overcoming the fluid support of said die core ring while maintaining engagement of said chuckwall between said punch core ring and said die core ring.

Apparatus for forming a container end piece from a sheet of material in a press having a fixed base and a movable platen, comprising:

• (a) a die core ring carried by the fixed base;
• (b) a punch shell carried by the movable platen to wipe the material over the die core ring to form an inverted cup upon movement of the movable platen toward the fixed base;
• (c) punch means carried by the movable platen concentrically inboard of said punch shell and telescopically receivable within said die core ring
• (1) whereby said punch means reverse said inverted cup and form a preliminary chuckwall and chuckwall angle upon further movement of the movable platen toward the fixed base;
• (d) said punch means including:
• (1) a punch core and
• (2) a punch core ring movable with said movable platen and relatively of said punch core still further toward said fixed base to form a final chuckwall in the cup and maintain said chuckwall angle.

Apparatus for forming a container end piece from a workpiece in a double acting press having a fixed base and inner and outer slides movable toward and away from the base, comprising:

• (a) a die core fixed to the base;
• (b) a die core ring fluidly supported on the base in concentric, spaced relationship with said die core;
• (c) a lower pressure sleeve fluidly supported on the base in concentric relationship with said die core ring;
• (d) a punch core carried by inner slide for fluidly actuated movement with respect thereto and disposed in opposed relationship with said die core;
• (e) a punch core ring carried by the inner slide in concentric relationship with said punch core;
• (f) an upper pressure sleeve carried by the outer slide in concentric relationship with said punch core ring and opposed relationship with said die core ring;
• (g) a punch shell carried by the outer slide in concentric relationship with said upper pressure sleeve and opposed relationship with said lower pressure sleeve;
• (h) said upper pressure sleeve being movable toward the base to hold the workpiece against said die core ring;
• (i) said punch shell being movable toward the base to form an inverted cup by bending the periphery of the workpiece about said die core ring;
• (j) said punch core and said punch core ring being movable toward the base to reverse said inverted cup and form an end piece having a preliminary chuckwall, a chuckwall angle, a central bottom panel and a radiused area between said chuckwall and said central bottom panel thereof;
• (k) said punch core ring being further movable toward said base after said punch core bottoms on said die core to shorten said chuckwall while maintaining engagement therewith to maintain said chuckwall angle and reduce said radius.