Frame tube for frame of light-weight bicycle that is utilized for performing e.g. multi-purpose recreational activities in specific route, has weld bead extending spirally around tube body, and set of round holes distributed on tube body

摘要

The tube (A) has a spiral tube body comprising multiple spiral coils and made of an alloy sheet that is chosen from a group consisting of 6-4 titanium alloy sheet, an American society for testing and materials (ASTM) A313-type high-strength stainless steel alloy sheet or ASTM A564-type high-strength stainless steel alloy sheet. A weld bead extends spirally around the spiral tube body for securing together the two adjacent spiral coils of the spiral tube body. A set of round holes (A1) are distributed on the spiral tube body.