High performance light weight vehicle frame
This invention relates to polygonal frame structures made from anisotropic materials, and methods for their construction. The polygonal frame structures include at least one frame member that is constructed as a torsion box. The torsion box is constructed with layers of anisotropic materials, resulting in a lightweight, torsionally stiff polygonal frame. Natural and/or man-made anisotropic materials may be used. Wood may be used as a natural anisotropic material. The invention is applicable to bicycles and other vehicles, as well as other products, where frame structures having light weight and torsional stiffness are advantageous.
1 . A vehicle frame member, comprising:
at least three panels joined together in an arrangement that provides a hollow tube;
each panel of the at least three panels comprising two or more layers of material characterized by values of strength and stiffness along a first axis that are different from values of strength and stiffness along a second axis, high strength to weight ratio, and density of wood;
wherein the two or more layers of material of each panel are alternatingly disposed with the first axis oriented at different selected angles relative to a longitudinal axis of the vehicle frame member, and with the second axis oriented at different selected angles relative to the longitudinal axis of the vehicle frame member;
wherein the vehicle frame member exhibits a selected higher torsional stiffness along the longitudinal axis and a selected lower associated axial stiffness along the longitudinal axis according to the selected orientations of the first and second axes of the material.
2 . The vehicle frame member of claim 1 , wherein the selected angle of the first axis and the selected angle of the second axis are substantially equal and opposite, relative to the longitudinal axis of the vehicle frame member.
3 . The vehicle frame member of claim 1 , wherein at least one panel comprises at least two layers of the same material.
4 . The vehicle frame member of claim 1 , wherein at least one panel comprises at least two layers of at least two different materials.
5 . The vehicle frame member of claim 1 , wherein a number of layers of material of at least one panel is different from a number of layers of material of other panels.
6 . The vehicle frame member of claim 1 , wherein at least one material comprises a natural material.
7 . The vehicle frame member of claim 6 , wherein the natural material is selected from bamboo, hemp, and wood.
8 . The vehicle frame member of claim 6 , wherein the natural material comprises wood.
9 . The vehicle frame member of claim 1 , wherein the two or more layers comprise two or more species of wood.
10 . The vehicle frame member of claim 1 , wherein at least one layer of the two or more layers comprises a man-made material and at least one other layer of the two or more layers comprises a natural material.
11 . A polygonal vehicle frame comprising three or more vehicle frame members according to claim 1 .
12 . The polygonal vehicle frame of claim 11 , wherein at least a first vehicle frame member is a first torsion box and at least a second vehicle frame member is a second torsion box;
wherein at least the first torsion box has selected torsional stiffness and axial stiffness that is different from a selected torsional stiffness and axial stiffness of the at least second torsion box.
13 . The polygonal vehicle frame of claim 11 , wherein the vehicle is a bicycle.
14 . A method for constructing a vehicle frame member; comprising:
joining together at least three panels in an arrangement that provides a hollow tube;
wherein each panel of the at least three panels comprises two or more layers of material characterized by values of strength and stiffness along a first axis that are different from values of strength and stiffness along a second axis, high strength to weight ratio, and density of wood;
alternatingly disposing the two or more layers of material of each panel with the first axis oriented at different selected angles relative to a longitudinal axis of the vehicle frame member, and with the second axis oriented at different selected angles relative to the longitudinal axis of the vehicle frame member;
wherein the vehicle frame member exhibits a selected higher torsional stiffness along the longitudinal axis and a selected lower associated axial stiffness along the longitudinal axis according to the selected orientations of the first and second axes of the material.
15 . The method of claim 14 , wherein at least one material comprises a natural material selected from bamboo, hemp, and wood.
16 . The method of claim 14 , comprising joining together three or more vehicle frame members to construct a polygonal vehicle frame.
17 . The method of claim 16 , wherein at least a first vehicle frame member is a first torsion box and at least a second vehicle frame member is a second torsion box;
wherein at least the first torsion box has selected torsional stiffness and axial stiffness that is different from a selected torsional stiffness and axial stiffness of the at least second torsion box.
18 . The method of claim 16 , wherein the vehicle is a bicycle.