Patent ID: 7431317
Filing Date: 2008-10-07
Classification: B62K,Y10T

Abstract:
1. A bicycle frame tube made by a method comprising the steps of: drawing a tube having a first section with a first wall thickness connected to a second section with a second wall thickness that is different from the first wall thickness, the second section ending in an opening; radially and proportionally enlarging a cross-section of the second section of the tube, by forging the tube into a first shape, wherein the second section has a third wall thickness that is substantially equal to the first wall thickness of the first section; and disproportionally varying the cross-section of the second section by forging the first shape of the second section of the tube into a second shape, wherein a first end portion of the second section at the opening is disproportionally varied relative to a second end portion of the second section at the opening, and wherein a width of a cross-section of the second end portion at the opening is greater than a width of a cross-section of the first end portion at the opening.