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A bottle-shaped can manufacturing method for forming a shoulder portion having a slope and a diametrically small cylindrical neck portion integrally by further working a bottom side of a bottomed cylindrical can which is formed thinner at its trunk wall than at its bottom wall by drawing a metallic

A bottle-shaped can manufacturing method for forming a shoulder portion having a slope and a diametrically small cylindrical neck portion integrally by further working a bottom side of a bottomed cylindrical can which is formed thinner at its trunk wall than at its bottom wall by drawing a metallic sheet having a thickness of 0.1 to 0.4 mm and by executing at least one thinning working of a bending/extending working and an ironing working.

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1. A bottle-shaped can manufacturing method or forming a shoulder portion and a neck portion integrally by working a bottom side of a bottomed cylindrical can formed thinner at a trunk wall than at a bottom wall by drawing and ironing a metallic sheet, comprising:a diametrically small cylindrical po

1. A bottle-shaped can manufacturing method or forming a shoulder portion and a neck portion integrally by working a bottom side of a bottomed cylindrical can formed thinner at a trunk wall than at a bottom wall by drawing and ironing a metallic sheet, comprising:a diametrically small cylindrical portion forming step of: drawing the bottom wall and a portion of the trunk wall adjacent to the bottom wall into (i) a diametrically small bottomed cylindrical shape having a diameter less than a diameter of a remaining portion of the trunk wall and (ii) a curved face of a lower part of the shoulder portion by applying pressure on a bottom corner portion with a forming pusher having an outer face shape corresponding to a shape of the curved face of the shoulder portion to be formed and a drawing die having an inner face shape corresponding to the shape of the curved face of the shoulder portion to be formed while holding the curved face of the shoulder portion with the forming pusher and the drawing die simultaneously; another diametrically small cylindrical portion forming step of: re-drawing the diametrically small bottomed cylindrical shape into a diametrically smaller bottomed cylindrical shape and holding the bottom corner portion with a blank holder having a tapered face, a re-drawing die having a tapered face, and a re-drawing punch; and a shoulder portion reforming step of: pushing and extending the shoulder portion formed by said diametrically small cylindrical portion forming steps after a diameter of the diametrically smaller bottomed cylindrical shape is substantially equal to a diameter of said neck portion by executing drawing working of the another diametrically small cylindrical portion forming step one or two more times. 2. The bottle-shaped can manufacturing method according to claim 1, wherein said another diametrically small cylindrical portion forming step further comprises:re-drawing said diametrically smaller bottomed cylindrical shape and holding the bottom corner portion of said diametrically smaller bottomed cylindrical shape with another blank holder having a tapered face, another re-drawing die having a tapered face, and another re-drawing punch, wherein the diametrically smaller bottomed cylindrical shape is redrawn until a portion of the shoulder portion comes into contact with the tapered face of said another blank holder and the tapered face of said another re-drawing die. 3. The bottle-shaped can manufacturing method according to claim 2, further comprising:reforming said shoulder portion in its entirety into a smooth curved face by pinching most of said shoulder portion between a pair of forming tools to push and extend the shoulder portion. 4. The bottle-shaped can manufacturing method according to claim 3,wherein the forming tools comprise a die configured to contact an outer face of the shoulder portion and a pusher configured to contact an inner face of the shoulder portion, which have a shape of a virtual curve face extending from the curved shoulder face. 5. The bottle-shaped can manufacturing method according to claim 1,wherein the blank holder includes a holder having at its leading end portion a slope having a substantially straight longitudinal section profiling a tangent line to arcuate longitudinal section of a virtual curved face leading to the curved shoulder face, and the redrawing die includes a die having at its portion to face the slope of the holder a slope having a shape of a substantially straight longitudinal section profiling a tangent line to an arcuate longitudinal section of a virtual curved face leading to the curved shoulder face, and at its portion on the leading end side from the slope a convex curved face of an arcuate longitudinal section having a larger external diameter than an external diameter of the slope of the holder, wherein said another diametrically small cylindrical portion forming step further comprises: re-drawing said diametrically smaller bottomed cylindrical shape and holding the bottom corner portion of said diametrically smaller cylindrical shape with the holder, the die, and the re-drawing punch, wherein the diametrically smaller bottomed cylindrical shape is redrawn until a portion of the shoulder portion comes into contact with a slope of the face of said holder and a slope of the face of said die. 6. The bottle-shaped can manufacturing method according to claim 5,wherein the slope of the face of said holder, and the slope of said die, used when the another diametrically small cylindrical portion forming step is repeated two or more times with the holder, are substantially identical to the slope of the face of said holder and the slope of said die used initially in the diametrically small cylindrical portion forming step. 7. The bottle-shaped can manufacturing method according to claim 5, further comprising:reforming said shoulder portion into a smooth slope by pinching said shoulder portion in its entirety between a pair of forming tools and by pushing the diametrically smaller cylindrical shape with said re-drawing punch, to apply a pulling force to push and extend said shoulder portion. 8. The bottle-shaped can manufacturing method according to claim 1, wherein said metallic sheet comprises a thermoplastic resin film laminated on an aluminum alloy sheet.9. The bottle-shaped can manufacturing method according to claim 1, wherein said metallic sheet comprises a thermoplastic resin film laminated on a surface-treated steel sheet.10. The bottle-shaped can manufacturing method according to claim 1, wherein said bottom side is thinned such that a thickness of the trunk wall adjacent the bottom wall is (i) less than a thickness of the metallic sheet before drawing and (ii) at least 60% of the thickness of said metallic sheet.11. A bottle-shaped can manufacturing method for forming a shoulder portion and a neck portion integrally by working a bottom side of a bottomed cylindrical can formed thinner at a trunk wall than at a bottom wall by drawing and ironing a metallic sheet, comprising:a diametrically small cylindrical portion forming step of: drawing the bottom wall and a portion of the trunk wall adjacent the bottom wall into (i) a diametrically small bottomed cylindrical shape having a diameter less than a diameter of a remaining portion of the trunk wall and (ii) a curved face of the shoulder portion by applying pressure on a bottom corner portion with a forming pusher having an outer face shape corresponding to a shape of the curved face of the shoulder portion to be formed and a drawing die having an inner face shape corresponding to the shape of the curved face of the shoulder portion to be formed by holding the curved face of the shoulder portion with the forming pusher and the drawing die simultaneously; another diametrically small cylindrical portion forming step of: re-drawing the diametrically small bottomed cylindrical shape into a diametrically smaller bottomed cylindrical shape and holding the bottom corner portion by at least one of a blank holder having a predetermined tapered face, a re-drawing die having a tapered face, and a re-drawing punch diametrically smaller than the re-drawing punch; and a shoulder portion reforming step of: pushing and extending the shoulder portion formed by said diametrically small cylindrical portion forming steps after a diameter of the diametrically smaller bottomed cylindrical shape is substantially equal to a diameter of said neck portion by executing drawing working of the another diametrically small cylindrical portion forming step one or two more times. 12. A bottle-shaped can manufacturing method for forming a shoulder portion and a neck portion integrally by working a bottom side of a bottomed cylindrical can formed thinner at a trunk wall than at a bottom wall by drawing and ironing a metallic sheet, comprising:a first diametrically small cylindrical portion forming step of: drawing the bottom wall and a portion of the trunk wall adjacent to the bottom wall of the bottomed cylindrical can into (i) a diametrically small bottomed cylindrical portion having a diameter less than a diameter of a remaining portion of the trunk wall and (ii) a curved face of a lower part of the shoulder portion of the bottle-shaped can to be formed, by applying pressure on a bottom corner portion of the cylindrical can with a forming pusher having an outer face shape corresponding to a shape of the curved face of the lower part of the shoulder portion of the bottle-shaped can to be formed, a drawing die having an inner face shape corresponding to the shape of the curved face of the lower part of the shoulder portion of the bottle-shaped can to be formed, and a drawing punch configured to urge a portion of the bottom wall into the drawing die while holding the portion of the trunk wall adjacent to the bottom wall between the forming pusher and the drawing die; a second diametrically small cylindrical portion forming step of: re-drawing a bottom portion and a cylindrical portion of the trunk wall adjacent to the bottom wall of the diametrically small bottomed cylindrical portion and a repetition of re-drawing a diametrically smaller bottomed cylindrical portion to be formed with each of a plurality of pushers each having a tapered face, mating re-drawing dies each having correspondingly tapered faces and mated re-drawing punches having different diameters, until a bottomed cylindrical portion having a diameter equal to a diameter of the neck portion and extending into a shoulder wall continuing from the curved face of the lower part of the shoulder portion is obtained; and a shoulder portion reforming step of: pushing and smoothing the curved face of the lower part of the shoulder portion and the extended shoulder wall. 13. The bottle-shaped can manufacturing method according to claim 12,wherein the re-drawing and the repetition of re-drawing are effected such that a boundary of the diametrically small bottomed cylindrical portion and the curved face of the lower part of the shoulder portion and a boundary of the diametrically smaller bottomed cylindrical portion and the extended shoulder wall are pulled into a space between a pusher having a tapered face and a mated re-drawing die having a tapered face. 14. The bottle-shaped can manufacturing method according to claim 13,wherein the curved face of the lower part of the shoulder portion and the extended shoulder wall are reformed in their entirety into a smooth and continuous curvature by pulling through a space between a pair of forming tools contoured to a shape of the shoulder portion to be finally formed. 15. The bottle-shaped can manufacturing method according to claim 12,wherein each of the re-drawing dies has a relatively large relief at its entry portion, and the re-drawing and the repetition of re-drawing are effected such that a boundary of the diametrically small bottomed cylindrical portion and the curved face of the lower part of the shoulder portion and a boundary of the diametrically smaller bottomed cylindrical portion and the extended shoulder wall are pulled into a space between each pusher the mated redrawing die. 16. The bottle-shaped can manufacturing method according to claim 15,wherein each of the pushers has a substantially equally tapered face. 17. The bottle-shaped can manufacturing method according to claim 15,wherein the shoulder portion is reformed into a smooth slope in its entirety in a tangential continuation of the curved face of the lower part of the shoulder portion by pulling walls of the shoulder portion through a space between a pair of forming tools contoured to a shape of the shoulder portion to be finally formed. 18. The bottle-shaped can manufacturing method according to claim 12,wherein the metallic sheet comprises an aluminum alloy sheet laminated with at least one thermoplastic resin film. 19. The bottle-shaped can manufacturing method according to claim 12,wherein the metallic sheet comprises a surface-treated steel sheet laminated with at least one thermoplastic resin film. 20. The bottle-shaped can manufacturing method according to claim 12,wherein the bottom side of the bottomed cylindrical can is thinned such that a thickness of the trunk wall adjacent to the bottom wall is (i) less than a thickness of the metallic sheet before drawing and (ii) at least 60% of the thickness of the metallic sheet.