Composite bicycle frame and methods for its construction

A fiber reinforced plastic load bearing vehicle frame comprising:

• a thin single wall hollow lug having a first cylinder portion having a first axis and a second cylinder portion having a second diverging axis projecting at an angle from said first axis of said first cylinder portion said second cylinder portion being formed and arranged for receiving a tube;
• said second cylinder portion merging with said first cylinder portion at a compoundly curved wall portion and having a connecting portion formed and arranged for receiving said tube, said tube connected to said second cylinder portion at said connecting portion and said tube extending in a direction coaxial with said second axis;
• said connecting portion being spaced from said first cylinder portion such that said connecting portion is spaced away from the location of stress concentration on said lug when said frame is under riding load imposed by operation of said vehicle frame tending to change said angle and is spaced in the direction away from said first cylinder portion to substantially decrease said stress on said connecting portion;
• said thin single wall being defined by an interior surface and an exterior surface, and formed substantially exclusively of a plurality of fiber reinforcing layers in a cured resin matrix between said interior and exterior surfaces.

A lug for joining tubes comprising:

• a first single walled hollow tubular structural member having a first interior surface and a first exterior surface;
• a second single walled hollow tubular structural member extending outwardly from said first tubular member having a second interior surface and a second exterior surface, said second interior surface being a continuation of said first interior surface and said second exterior surface being a continuation of said first exterior surface;
• said first tubular member and second tubular member being formed in a single substantially homogenous section hollow structural unit of cured fiber reinforced plastic lamina having reinforcing fibers within a plastic matrix;
• said lamina being compacted one against another prior to curing, whereby voids between the lamina are substantially eliminated.

A composite lug and composite tube vehicle frame comprising:

• a composite lug including a solid shell of a single continuous wall having an interior surface and an exterior surface and having a first hollow tubular portion;
• said lug shell having a second hollow tubular portion extending outwardly from said first tubular portion;
• said first tubular portion and second tubular portion being formed in a single structural unit of cured fiber reinforced plastic lamina, said fibers being contained within a substantially homogenous resin matrix;
• said lamina being compacted one against another prior to curing, whereby voids between the lamina are substantially eliminated to provide a fiber volume between said interior surface and said exterior surface greater than 60%;
• said lug being bonded to a composite tube to complete said vehicle frame.

An all composite bicycle frame structural component formed as a hollow shell composed of two half portions, said component comprising:

• a shell formed as a continuous wall in a compound curved three dimensional shape,
• said shell being a solid composite consisting essentially of a plurality of fiber layers in a first half portion having fibers of a first layer oriented in juxtaposed relation to the fibers of a second layer and a plurality of fiber layers in a second half portion having fibers of a third layer oriented in juxtaposed relation to the fibers of a fourth layer,
• said layers being contained within a cured resin matrix wherein said substantially continuously surrounds said fibers;
• said first and second layers of said first half portion being oriented in an overlapping manner with said third and said fourth layers, within said resin matrix;
• said shell having an interior surface and an exterior surface with said fibers substantially parallel to both said surfaces and the area between said surfaces consisting essentially of said fiber layers in said resin matrix in substantially uniform density and having a fiber volume between said surfaces of greater than 60%.