Method and apparatus for forming container end shells

Abstract

Method and apparatus for forming end shells for containers with a peripheral curl and an annular reinforcing rib in a single stroke cycle of a press which includes a punch core, a punch shell, and a pressure sleeve carried by an inner ram of the press. A cut edge is carried by an outer ram for forming a flat disc-shaped blank at a first level from a strip of sheet material. A die core is mounted on the base at a second level and is surrounded by concentric inner and outer die core rings. A cup-shaped blank is formed from the flat blank by movement of the punch core, pressure sleeve, and punch shell through a blank and draw die. The cup is clamped at the second level between the die core and punch core and formed into an end shell by movement of the punch core, pressure sleeve, and punch shell into clamping engagement with the die core, and inner and outer die core rings. Reverse movement of the outer die core ring and punch shell draws a peripheral edge of the end shell about a curl groove formed in the outer die core ring to form the peripheral curl. The end shell then is ejected form the press at the second level by pressurized air.