Patent ID: 7950263

Claim:
A can body manufacturing method which is performed using a can body manufacturing apparatus having a first rotating body and a second rotating body that are supported rotatable around rotation axes that are parallel with each other, and in which a can body is formed by creating embossing processed portions on a drum portion of the can body by placing the first rotating body inside a cylindrical can base having one closed end, and placing the second rotating body outside the can base, and then moving the first and second rotating bodies towards each other and, in a state in which the drum portion of the can base is sandwiched between respective outer circumferential surfaces of these rotating bodies, rotating the first and second rotating bodies around their rotation axes, the method comprising the steps of; providing the first rotating body with a first concave portion formed on an outer circumferential surface of the first rotating body so as to be recessed in an inwardly-radial direction of the first rotating body, and a first convex portion formed in the first concave portion so as to protrude in an outwardly-radial direction of the first rotating body; providing the second rotating body with a second convex portion formed at a portion corresponding to the first concave portion on an outer circumferential surface of the second rotating body so as to protrude in an outwardly-radial direction of the second rotating body, and a second concave portion that formed in a portion of the second convex portion corresponding to the first convex portion so as to be recessed in an inwardly-radial direction of the second rotating body; pushing the drum portion by the second convex portion from the outer circumferential surface side of the drum portion in an inwardly-radial direction thereof such that at least some of the total amount of deformation in the inwardly-radial direction becomes elastic deformation when the drum portion is sandwiched between the outer circumferential surfaces of the first and second rotating bodies; fitting the first convex portion to the second concave portion via the drum portion in a state where the inner circumferential surface side corresponding to the elastically deformed portion has been pushed into the first concave portion; thereafter, the drum portion corresponding to the first concave portion and the: second convex portion is moved restoratively in an outwardly-radial direction of the drum portion by the elastic restorative force of the drum portion when the sandwiching between the outer circumferential surfaces of the first and second rotating bodies is stopped; and positioning the outer circumferential surface of that portion of the drum portion corresponding to the first convex portion and the second concave portion further towards the outer side in the radial direction of the drum portion than the outer circumferential surface of the drum portion excluding those portions corresponding to the first convex portion and the second concave portion.