Cover lifter

1. A spa cover lifter for lifting a spa cover, the spa cover comprising a first section and a second section pivotably coupled to the first section at a hinge interface, the spa cover lifter comprising:

a first frame member coupled to the first section of the spa cover;

a second frame member coupled to the second section of the spa cover, wherein the first frame member and the second frame member are pivotably coupled at about the hinge interface;

a drive system;

a first cable extending from the drive system to the first frame member; and

a torsion spring positioned at about the interface between the first frame member and the second frame member, wherein the torsion spring is configured to release a torque tending to rotate the first section off of a spa about the interface until the first section is rotated off of the spa by a predetermined angle, and wherein the torsion spring is also configured to store a torque tending to rotate the second section onto the spa about the hinge interface when the first section is rotated off of the spa by more than a second predetermined angle.

2. The spa cover lifter of claim 1 , wherein the drive system is configured to retract the first cable.

3. The spa cover lifter of claim 1 , further comprising a retractable post assembly, wherein the first cable interfaces with the retractable post assembly between the drive system and the first frame member.

4. The spa cover lifter of claim 1 , wherein the first cable is coupled to the first frame member at about an end of the first frame member opposite the second frame member.

5. The spa cover lifter of claim 1 , wherein the first frame member and the second frame member are configured to be positioned between a jacket of the spa cover and a core of the spa cover.

6. The spa cover lifter of claim 5 , wherein the first frame member is configured to be positioned between the jacket of the spa cover and a first section of the core of the spa cover above the first section of the core of the spa cover.

7. The spa cover lifter of claim 5 , wherein the second frame member is configured to be positioned between the jacket of the spa cover and a second section of the core of the spa cover below the second section of the core of the spa cover.

8. The spa cover lifter of claim 5 , wherein the second frame member is configured to be positioned between the jacket of the spa cover and a second section of the core of the spa cover above the second section of the core of the spa cover.

9. A cover lifter for lifting a cover from a substantially horizontal position to a folded and substantially vertical position, the cover comprising a first section and a second section pivotably coupled to the first section at a hinge interface, the cover lifter comprising:

a first frame member coupled to the first section of the cover;

a second frame member coupled to the second section of the cover, wherein the first frame member and the second frame member are pivotably coupled at about the hinge interface;

a first cable extending from the drive mechanism to the first frame member such that retracting the first cable towards the drive system causes the first section of the cover to rotate up away from the substantially horizontal position;

a drive system configured to retract the first cable

a torsion spring positioned at about the interface between the first frame member and the second frame member, wherein the torsion spring is configured to release a torque tending to rotate the first section up away from the substantially horizontal position until the first section is rotated by a predetermined angle, and wherein the torsion spring is also configured to store a torque tending to rotate the second section towards the horizontal position when the first section is rotated by more than a second predetermined angle.

10. The cover lifter of claim 9 , further comprising a retractable post assembly, wherein the first cable interfaces with the retractable post assembly between the drive system and the first frame member.

11. The cover lifter of claim 9 , wherein the first cable is coupled to the first frame member at about an end of the first frame member opposite the second frame member.

12. A method of lifting a cover from a substantially horizontal position to a folded and substantially vertical position, the cover comprising a first section and a second section pivotably coupled to the first section at a hinge interface, the method comprising:

applying a first force tending to rotate the first section up away from the substantially horizontal position and towards the second section of the cover;

releasing a first torque about the hinge interface tending to rotate the first section toward the second section until the first section is rotated toward the second section by a predetermined angle;

after releasing the first torque, storing a second torque about the hinge interface, the second torque tending to rotate the first section away from the second section; and

applying a second force tending to rotate the cover to the folded and substantially vertical position, wherein the first force and the second force are exerted through a first cable.

13. The method of claim 12 , wherein applying the first force and applying the second force comprise retracting the first cable.

14. The method of claim 12 , wherein the torque is stored with a cylinder.

15. The method of claim 12 , wherein the torque is stored with a torsion spring.

16. The method of claim 12 , wherein the torsion spring is positioned at about the hinge interface.