초록 ▼

The disclosure relates to a novel shell such as used in the manufacture of can ends, and to a method and tools for making such a shell. A non-circular blank having rounded corners is cut from thin metal. The blank is oblong in a direction transverse to the grain of the metal. A first set of tools se

The disclosure relates to a novel shell such as used in the manufacture of can ends, and to a method and tools for making such a shell. A non-circular blank having rounded corners is cut from thin metal. The blank is oblong in a direction transverse to the grain of the metal. A first set of tools separates the blanks and forms a substantially flat central panel and an upward-extending chuck wall about the edge of the panel to produce a partially formed shell. The junction area between said panel and said chuck wall has a relatively large radius of curvature at this time. A second set of tools forms in the blank a lip extending outward from the upper end of the chuck wall and generally parallel to said panel; then the panel and the chuck wall are separately gripped, followed by relative movement between the panel and the chuck wall while wrapping the junction area around a forming punch to form a panel wall in said junction area extending upward from the inner part of said chuck wall. Then the lip is formed into a curl edge section which ends in an inner curl diameter that is round and concentric with the chuck wall, and has progressively lesser radii of curvature from upper end of the chuck wall to the inner curl diameter. The resulting shell is characterized by a curl diameter being round and concentric with the chuck wall and essentially uniformly spaced therefrom, and by having an essentially constant thickness throughout the central panel, the panel wall and chuck wall and the curved section therebetween.

대표청구항 ▼

In a method of forming shells for use in the manufacture of can ends wherin a rounded non-circular blank is formed from a sheet of thin metal; the improvement comprising orienting the blank on the metal such that the blank has a greater width across the grain of the metal than along such grain, then

In a method of forming shells for use in the manufacture of can ends wherin a rounded non-circular blank is formed from a sheet of thin metal; the improvement comprising orienting the blank on the metal such that the blank has a greater width across the grain of the metal than along such grain, then forming into the blank a substantially flat central panel and an upward-extending chuck wall about the edge of the panel to produce a partially formed shell, the junction area between the panel and the chuck wall defining a relatively large radius of curvature; and forming into the blank a lip extending outward from the upper end of the chuck wall and generally parallel to the panel. In a method of forming sheels for use in the manufacture of can ends wherein a non-circular blank having rounded corners is formed from a sheet of thin metal: the improvement comprising orienting the blank on the metal such that the blank is oblong in a direction transverse to the grain of the metal to compensate for greater elongation of the blank along the grain during forming; then forming in the blank a substantially flat central panel and an upward-extending chuck wall about the edge of the central panel to produce a partially formed shell, the junction area between the central panel and the surrounding chuck wall defining a relatively large radius of curvature; and forming into the blank a lip extending outward from the upper end of the chuck wall and generally parallel to the panel.