Patent ID: 6807839
Filing Date: 2004-10-26
Classification: B21D

Abstract:
A cold folding method for a hollow tube of magnesium material, wherein the method uses an apparatus comprising:a male mold, movable up and down, having a male lower surface portion at a lower portion thereof, male side surface portions at opposite sides of the male lower surface portion, male curved surface portions between the male lower surface portion and the male side surface portions, male lower protection members at the male lower surface portion and male side portion protection members at opposed sides of the male side surface portions, and a pair of female molds, each having a female front surface portion, a female upper surface portion, a female curved surface portion between the female front surface portion and the female upper surface portion, front portion guide members at the female front surface portion, and upper portion guide members at the female upper surface portion, the method comprising: providing inner ribs respectively at opposite sides of the hollow tube; placing a section of the hollow tube in the apparatus such that opposed ends of the section are received in the upper portion guide members of the female molds and a portion of the hollow tube between the opposed ends of the section is received in an inner portion of the male lower protection members of the male mold; and lowering the male mold to fold the hollow tube by a combination of the male curved surface portions of the male mold and the female curved surface portions of the female molds.