Spring array and method for door counterbalancing

1. A system for exerting torque on a shaft comprising:

a spring assembly having;

a spring;

a companion member to the spring, wherein at least one of the spring and the companion member is in compression and the other of the spring and companion member is in tension;

connecting structure for transmitting a force associated with the spring outside of the spring assembly; and

a gear train for connecting the connecting structure to the shaft to apply torque to the shaft.

2. The system of claim 1 , wherein the spring assembly is connected to a sun spring.

3. The system of claim 1 , further comprising an end plate located at an end of the spring and the connecting structure attaches to the end plate with a snap fitting.

4. The system of claim 3 , wherein the snap fitting includes a resilient hook urging against a structure defining a hole in the end plate.

5. The system of claim 1 , wherein the spring assembly further comprises a plurality of spring assemblies located proximate to the shaft and connected to the shaft via the gear train to impart torque on the shaft.

6. The system of claim 5 , wherein the plurality of spring assemblies are located in an array about the shaft.

7. The system of claim 6 , wherein the plurality of spring assemblies are located in an annular array about the shaft.

8. The system of claim 1 , further comprising an upward acting door operatively connected to the shaft such that when the shaft rotates in one direction the door moves to an open position and when the shaft rotates in the other direction the door moves to a closed position.

9. The system of claim 8 , wherein the system is a counter balance system for the door.

10. The system of claim 1 , wherein the gear train includes a planetary gear system.

11. The system of claim 1 , further comprising an end plate located at an end of the spring and a second connecting structure extending through a hole in the end plate.

12. A system for exerting torque on a shaft comprising:

a plurality of spring assemblies arranged in an array around the shaft, each spring assembly having;

a spring and;

connecting structure for transmitting a force associated with the spring; and

a gear train for connecting the connecting structure to the shaft and configured to apply the force associated with the spring to the shaft in the form of torque on the shaft.

13. The system of claim 12 , further comprising an outer casing for each spring, the outer casing for each spring housing the spring, wherein at least one of the spring and outer casing is in compression and the other of the spring and outer casing is in tension.

14. The system of claim 13 , wherein each spring assembly contains an end plate located at an end of the outer casings and springs and the connecting structures extend through the end plate.

15. The system of claim 14 , wherein the connecting structures attach to the end plates via a snap fit system.

16. The system of claim 12 , further including an upward acting door attached to the shaft and counterbalanced by the plurality of spring assemblies.

17. A method of exerting torque on a shaft comprising:

arranging a plurality of spring assemblies arranged in an array around the shaft, each spring assembly having;

a spring and;

connecting structure for transmitting a force associated with the spring;

attaching a gear train to the connecting structure; and

configuring the gear train to apply the force associated with the spring to the shaft in the form of torque on the shaft.

18. The system of claim 17 , wherein each spring assembly contains an end plate located at an end of the springs and the connecting structures extend through the end plate.

19. The system of claim 18 , using a snap fit connection to connect the connecting structures to the end plate.

20. The system of claim 17 , further connecting an upward acting door to the shaft and counterbalancing the door with the plurality of spring assemblies.