Patent ID: 6866280
Filing Date: 2005-03-15
Classification: B21D,B62K

Abstract:
1. A bicycle frame comprising: a plurality of frame parts which are connected to each other; at least one of said frame parts including a tube body and at least one connection tube projecting from said tube body in a direction different from the direction of extension of said tube body; said at least one of said frame parts being formed via a process which comprises hydraulically forming a one-piece metallic tube blank by introducing a hydraulic pressure into said tube blank to deform and expand said tube blank so as to form at least one expanded wall part projecting from said tube blank in a direction different from the direction of extension of said tube blank, and machining said expanded wall part to form said connection tube; and wherein said frame parts include a one-piece unitary unit composed of a cross bar, a down tube, and head tube, said one-piece unitary unit being formed via said process, in which said process further includes the step of bending said tube blank to form two tube sections which form an acute angle therebetween and a turn between said tube sections, said tube blank being hydraulically formed such that said tube sections are formed into said cross bar and said down tube and such that said expanded wall part projects from said turn away form said tube sections to form said head tube, said expanded wall part being machined to form two openings at two opposite ends of said expanded wall part, which are opposed to one another along a direction transverse to said tube sections.