Composite springs and methods of manufacture

1. A composite spring comprising:

a core; and

multiple layers of a cured resin-impregnated composite fiber wound around the core, wherein the core and the multiple layers of cured resin-impregnated composite fiber form a spring having a desired helical pitch, diameter and spring rate; and

wherein the multiple layers of cured resin-impregnated composite fiber are formed on the core by (a) rotating a straight form of the core at a desired rate and wherein fiber is pulled from spools and impregnated with resin as the spools travel linearly at a desired rate with respect to the longitudinal axis of the straight form of the core so as to allow each layer of the resin-impregnated composite fiber to be laid down in accordance with desired angles, and (b) the straight form of the core with resin-impregnated composite fiber is wrapped on a spring form and allowed to cure, and (c) the spring form is removed from the cured resin-impregnated composite fiber.

2. A composite spring as in claim 1 wherein the multiple layers of cured resin-impregnated composite fiber are wound around the core at an angle between 5 and 90 degrees relative to the longitudinal axis of the core.

3. A composite spring as in claim 2 wherein different layers of the cured resin-impregnated composite fiber are wound at different angles.

4. A composite spring as in claim 2 wherein the composite spring has a circular cross-section.

5. A composite spring as in claim 2 wherein the composite spring has a non-circular cross-section.

6. A composite spring as in claim 2 wherein the angle of the wound composite fiber is varied along the length of the spring to form a spring with different spring properties along the length of the spring.

7. A composite spring as in claim 6 wherein the spring properties include torsional strength and bending strength.

8. A composite spring as in claim 1 wherein the thickness ratio of the core to the multiple layers of the cured resin-impregnated composite fiber is between 0.0001 and 0.9999.

9. A composite spring as in claim 8 wherein the thickness ratio of the core to the multiple layers of the cured resin-impregnated composite fiber is between 0.0001 and 0.3.

10. A composite spring as in claim 1 wherein the cured resin-impregnated composite fiber is carbon fiber.

11. A composite spring as in claim 1 wherein the core is removed after curing.

12. A composite spring as in claim 1 wherein different layers of the cured resin-impregnated composite fiber are composed of different composite materials.

13. A method of manufacturing a composite spring comprising the steps of:

a. winding resin-impregnated composite fiber over a core to create a wet fiber cord;

b. wrapping the wet fiber cord on a spring mold and allowing the wet fiber cord to cure to form a cured fiber spring; and

c. removing the cured fiber spring from the spring mold,

wherein multiple layers of cured resin-impregnated composite fiber are wound on the core by rotating a straight form of the core at a desired rate and wherein fiber is pulled from spools and impregnated with resin as the spools travel linearly at a desired rate with respect to the longitudinal axis of the straightened form of the core so as to allow each layer of the resin-impregnated composite fiber to be laid down in accordance with desired angles.

14. A method as in claim 13 wherein the spring mold has a helical groove for supporting the wet fiber cord, the helical groove having an inner supporting surface corresponding to the desired inner cross-section of the composite spring.

15. A method as in claim 13 wherein the flexible core is removed after curing.