| CPC B21D 37/10 (2013.01) | 1 Claim |
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1. A pressing die for an uncurled shell of a pressure-resistant easy open end, the uncurled shell comprising a sealing portion, a countersink portion, a ferrule arc portion, an upward extension portion of ferrule and a center panel; a first annular recess being formed between the countersink portion, the ferrule arc portion and the upward extension portion of ferrule; the sealing portion being formed by a first straight portion, a first arc portion, a second arc portion, and a third arc portion; the countersink portion being formed by a second straight portion, a fourth arc portion, a fifth arc portion, a sixth arc portion and a third straight portion: the ferrule arc section being formed of a seventh arc portion: the upward extension portion of ferrule being formed a fourth straight line and an eighth arc portion; and the center panel being formed by a fifth straight line; the pressing die comprising a lower die and an upper die; wherein:
the lower die comprises a lower die base, a lower die core ring, a lower die core, a lower pressing ring, and a lower blade, wherein:
the lower die base is a cylinder with an upper opening;
the lower die core ring is fixed in the lower die base and concentric with the lower die base;
an acting part of the lower die core is a cylindrical body, which is embedded in the lower die core ring and slidably matched with the lower die core ring in upward and downward directions;
a first air chamber is sealed and formed under the lower die core in the lower die core ring, and air pressure of the first air chamber supports the lower die core;
the lower pressing ring is embedded between the lower die base and the lower die core ring, and a second air chamber is sealed and formed between the lower die base and the lower die core ring under the lower pressing ring, and air pressure of the second air chamber supports the lower pressing ring; and
the lower blade is fixed on an edge of the upper opening of the lower die base, and a lower cutting edge is provided on an inner edge of a top of the lower blade;
the upper die comprises an upper die base, an upper die core, an upper inner forming ring, an upper outer forming ring and an upper blade, wherein:
the upper die base is a cylinder with a lower opening;
an acting part of the upper die core is a cylindrical body, which is arranged in the upper die base and concentric with the upper die base, and the upper die core is slidably matched with the upper die base in the upward and downward directions;
a third air chamber is sealed and formed above the upper die core in the upper die base, and air pressure of the third air chamber presses against the upper die core;
the upper inner forming ring is embedded between the upper die core and the upper die base, and a fourth air chamber is sealed and formed between the upper die core and the upper die base and above the upper inner forming ring, and air pressure of the fourth air chamber presses against the upper inner forming ring;
the upper outer forming ring is an embedded between the upper die base and the upper inner forming ring, and a fifth air chamber is sealed and formed between the upper die base and the upper inner forming ring and above the upper outer forming ring, and air pressure of the fifth air chamber presses against the upper outer forming ring; and
the upper blade is fixed on an edge of the lower opening of the upper die base, and an upper cutting edge matched with the lower cutting edge is provided on an outer edge of a bottom of the upper blade;
wherein:
the upper outer forming ring and the upper inner forming ring of the upper die match with the lower die core ring of the lower die, wherein a top of the lower die core ring is provided with a contour corresponding to the first straight portion, the first arc portion, the second arc portion, the third arc portion, the second straight portion, the fourth arc portion, the fifth arc portion, the sixth arc portion and the third straight portion of the uncurled shell;
an annular depression is formed at a top of the lower die core ring, the annular depression corresponding to the second straight portion, the fourth arc portion, the fifth arc portion and sixth arc portion of the uncurled shell;
a bottom of the upper outer forming ring is provided with a contour corresponding to the second arc portion of the uncurled shell, and parts at the bottom of the upper outer forming ring corresponding to the first arc portion and the third arc portion of the uncurled shell are suspended relative to the top of the lower die core ring in a closed state;
a bottom of the upper inner forming ring is provided with a contour corresponding to the fourth arc portion and the fifth arc portion of the uncurled shell, and parts at the bottom of the upper inner forming ring corresponding to the second straight portion, the sixth arc portion and third straight portion of the uncurled shell are suspended relative to the top of the lower die core ring in the closed state;
the upper die core of the upper die matches with the lower die core of the lower die, a top of the lower die core is provided with a contour corresponding to the seventh arc portion, the fourth straight portion, the eighth arc portion and the fifth straight portion of the uncurled shell, and a second annular recess is formed on the top of the lower die core corresponding to the seventh arc portion, the fourth straight portion and the eighth arc portion of the uncurled shell;
a bottom of the upper die core is provided with a contour corresponding to the fifth straight portion of the uncurled shell; and
the bottom of the upper die core is provided with a downward raised fillet at an edge of the bottom of the upper die core, the raised fillet corresponding to the eighth arc portion of the uncurled shell, and parts at the bottom of the upper die core corresponding to the seventh arc portion and the fourth straight portion of the uncurled shell are suspended relative to the top of the lower die core in the closed state.
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