Claims
- 1. In a chair seat that is rotatable between a seated position and an upright position, a spring assembly comprising:
a static cam attached to said chair seat, said static cam maintaining the same position with respect to said chair seat when said chair seat is rotated from the upright position to the seated position; a dynamic cam positioned adjacent said static cam, said dynamic cam both rotating and moving linearly with respect to said chair seat when said chair seat is rotated from the upright position to the seated position; and a spring positioned adjacent said dynamic cam, said spring being compressed by said dynamic cam when said chair seat is rotated from the upright position to the seated position, said spring also undergoing torsion when said chair seat is rotated from the upright position to the seated position, whereby both the compression and torsion experienced by said spring cause said spring to resist rotation of said chair seat to the seated position.
- 2. The chair seat spring assembly of claim 1 wherein said chair seat rotates about an axis, said axis passing through said static cam, said dynamic cam, and said spring.
- 3. The chair seat spring assembly of claim 1 wherein said spring is positioned such that said spring experiences substantially no torsion when said chair seat is in the upright position.
- 4. The chair seat spring assembly of claim 3 wherein said dynamic cam compresses said spring when said chair seat is in the upright position.
- 5. The chair seat spring assembly of claim 1 wherein said static cam and said dynamic cam are both cylindrical cams with a plurality of cam surfaces, said cam surfaces of said dynamic cam in contact with said plurality of cam surfaces of said static cam.
- 6. The chair seat spring assembly of claim 1 wherein said static and dynamic cams define a rest position for said chair seat between said upright position and said seated position; said static and dynamic cams causing said spring to exert a linear force on said dynamic cam when said chair seat is in said rest position such that said spring is partially compressed when said chair seat is in the rest position, said spring thereby exerting a force while said chair seat is in said rest position which must be overcome in order to move said chair seat out of said rest position.
- 7. The chair seat spring assembly of claim 1 wherein said static cam is attached to said chair seat without the use of any welding or separate mechanical fasteners.
- 8. The chair seat spring assembly of claim 7 further including a spring sleeve positioned around said spring, said spring sleeve attached to said static cam without the use of any welding or separate mechanical fasteners.
- 9. The chair seat spring assembly of claim 8 further wherein said spring is held in said chair seat without the use of any welding or separate mechanical fasteners.
- 10. The chair seat spring assembly of claim 6 wherein one of said static and dynamic cams includes a stop, said stop determining the position of the chair seat when said chair seat is in the rest position.
- 11. The chair seat of claim 2 further including a bearing adapted to be fixedly supported by a chair base, said bearing including a circular surface portion about which said chair seat rotates.
- 12. The chair seat of claim 11 wherein said bearing is made of plastic.
- 13. The chair seat of claim 12 wherein said bearing is attached via a snap-fit to a plastic bracket, said bracket fixedly mounted to the chair base.
- 14. The chair seat of claim 12 wherein said bracket includes a stop surface adapted to stop the rotation of the chair seat in at least one direction.
- 15. The chair seat of claim 14 wherein said chair seat includes a bucket adapted to support a cushion or which a user may sit, said bucket being made of molded plastic.
- 16. The chair seat of claim 13 further including a bearing block snap-fittingly secured to said bearing, said bearing block including a circular aperture dimensioned to receive the circular surface portion of said bearing.
- 17. The chair seat of claim 2 further including a right bearing and a left bearing adapted to be fixedly supported by a chair base, said right and left bearings including circular surface portions about which said chair seat rotates, said right and left bearings being of different lengths.
- 18. A method for controlling the movement of a chair seat that is rotatable from a rest position to a forward position comprising:
providing a spring; providing a cam member; providing a stop on said cam member, said stop corresponding to the rest position of the chair seat; positioning the spring in the chair seat such that the spring undergoes substantially no torsion when said chair seat is in the rest position; compressing the spring in the chair seat against the cam member when said spring is in the stop position such that said spring exerts a camming force on said chair seat to retain said chair seat in the rest position.
- 19. The method of claim 18 wherein said spring undergoes torsion and further compression when said chair seat is moved out of said rest position, said torsion and further compression causing said spring to exert a biasing force that biases said chair seat toward said rest position.
- 20. The method of claim 18 further comprising providing first and second camming surfaces on said cam member, said first camming surface used to bias said chair seat toward said rest position from a first direction, said second camming surface used to bias said chair seat toward said rest position from a second direction.
Parent Case Info
[0001] This application is a divisional of commonly assigned application Ser. No. 09/653,401 filed Sep. 1, 2000.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09653401 |
Sep 2000 |
US |
Child |
10266260 |
Oct 2002 |
US |