Six bar mechanism and control for chair

• US 7,784,870 B2
• Filed: 03/13/2008
• Issued: 08/31/2010
• Est. Priority Date: 03/13/2007
• Status: Active Grant

• Current Assignee: HNI Technologies Inc. (HNI Corporation)
• Original Assignee: HNI Technologies Inc. (HNI Corporation)
• Inventors: Machin, Keith, Roslund, Richard Neil Jr., Hahn, Jesse, Machael, Jay R.
• Primary Examiner(s): WHITE, RODNEY BARNETT
• Application Number:
  US12/048,116
• Publication Number:
  US 20080309135A1
• Time in Patent Office: 901 Days
• Field of Search: 297/300.5, 297/300.6, 297/300.7, 297/300.8, 297/301.4, 297/301.5, 297/301.6, 297/301.7
• US Class Current: 297/300.5
• CPC Class Codes: A47C 1/03255 with a central column, e.g. rocking office chairs
• CPC Class Codes: A47C 1/03266 with adjustable elasticity
• CPC Class Codes: A47C 1/03272 with coil springs
• CPC Class Codes: A47C 1/03274 of torsion type

Abstract

A chair according to embodiments of the present invention includes a base; a first linkage pivotably coupled to the base, a seat pivotably coupled to the first linkage, a second linkage pivotably coupled to the seat and pivotably coupled to the base, a back comprising a substantially upright portion and an attachment portion, the attachment portion pivotably coupled to the base at a first pivot point, and a third linkage pivotably coupled to the back at a second pivot point and pivotably coupled to the second linkage, wherein the second pivot point is on the attachment portion between the first pivot point and the substantially upright portion.

Claims

1. A chair comprising:

a base;

a first linkage pivotably coupled to the base;

a seat pivotably coupled to the first linkage;

a second linkage pivotably coupled to the seat and pivotably coupled to the base;

a back comprising a substantially upright portion and an attachment portion, the attachment portion pivotably coupled to the base at a first pivot point; and

a third linkage pivotably coupled to the back at a second pivot point and pivotably coupled to the second linkage,

wherein the second pivot point is located on the attachment portion between the first pivot point and the substantially upright portion.

2. The chair of claim 1, wherein the back reclines about the first pivot point, the chair further comprising:

a biasing element configured to apply a resistance force about the first pivot point, the resistance force resisting a reclining force of the back.

3. The chair of claim 2, wherein the biasing element is a coil spring.

4. The chair of claim 3, wherein the coil spring comprises a lever arm, and wherein the resistance force is adjustable by varying a location along the lever arm at which the reclining force is applied to the coil spring.

5. The chair of claim 4, further comprising:

a slider configured to transmit the reclining force from the back to the lever arm.

6. The chair of claim 5, wherein the slider slides substantially horizontally along the lever arm, and wherein a sliding force for sliding the slider is substantially less than the resistance force.

7. The chair of claim 5, wherein the slider slides between a locked position and an unlocked position, and wherein the slider in the locked position substantially prevents reclining of the back about the base.

8. The chair of claim 7, wherein the slider in the locked position is in a position closest to the seat.

9. The chair of claim 5, further comprising:

a cable sheath having a first end and a second end, the cable sheath coupled to the base; and

a cable extending through the cable sheath and slidable within the cable sheath, a first portion of the cable extending from the first end of the cable sheath, the first portion coupled to the slider, and a second portion of the cable extending from the second end of the cable sheath,

wherein sliding the second portion into and out of the cable sheath slides the slider back and forth along the lever arm.

10. The chair of claim 9, further comprising:

a button coupled to the second portion and configured to slide the second portion into and out of the cable sheath.

11. The chair of claim 10, wherein the lever is mounted to the seat.

12. The chair of claim 10, wherein the lever is mounted directly below the seat on a user'"'"'s left or right side when the user sits in the seat.

13. The chair of claim 2, wherein the resistance force is adjustable by varying a location along the biasing element at which the reclining force is applied.

14. The chair of claim 13, further comprising:

a slider configured to transmit the reclining force from the back to the biasing element.

15. The chair of claim 14, wherein the slider slides substantially horizontally along the biasing element, and wherein a sliding force for sliding the slider is substantially less than the resistance force.

16. The chair of claim 15, further comprising:

a cable sheath having a first end and a second end, the cable sheath coupled to the base; and

a cable extending through the cable sheath and slidable within the cable sheath, a first portion of the cable extending from the first end of the cable sheath coupled to the slider, and a second portion of the cable extending from the second end of the cable sheath,

wherein sliding the second portion into and out of the cable sheath slides the slider back and forth along the biasing element.

17. The chair of claim 16, further comprising:

a lever coupled to the second portion and configured to slide the second portion into and out of the cable sheath.

18. The chair of claim 1, wherein the base, the seat, the back, and the first, second, and third linkages comprise a Watts sixbar inversion II mechanism.

19. The chair of claim 1, wherein the seat is configured to move upwardly and toward the back when the back reclines about the base.

20. The chair of claim 1, wherein the back reclines about the base from a fully upright position to a fully reclined position, and wherein a centrode of the back with respect to the seat remains above the seat as the back reclines from the fully upright position to the fully reclined position.

21. The chair of claim 20, wherein the centrode substantially coincides with a hip point of a user sitting in the chair as the back reclines from the fully upright position to the fully reclined position.

22. A chair comprising:

a base;

a first linkage pivotably coupled to the base at a first pivot point;

a seat pivotably coupled to the first linkage at a second pivot point;

a second linkage pivotably coupled to the seat at a third pivot point and pivotably coupled to the base at a fourth pivot point;

a back pivotably coupled to the base at a fifth pivot point; and

a third linkage pivotably coupled to the back at a sixth pivot point and pivotably coupled to the second linkage at a seventh pivot point,

wherein the third, fourth, and seventh pivot points are not substantially collinear.

23. A chair comprising:

a base;

a first linkage pivotably coupled to the base at a first pivot point;

a seat pivotably coupled to the first linkage at a second pivot point;

a second linkage pivotably coupled to the seat at a third pivot point and pivotably coupled to the base at a fourth pivot point;

a back pivotably coupled to the base at a fifth pivot point; and

a third linkage pivotably coupled to the back at a sixth pivot point and pivotably coupled to the second linkage at a seventh pivot point,

wherein the back reclines about the base from a fully upright position to a fully reclined position, and wherein the second pivot point of the first linkage does not rotate over-center with respect to the first pivot point of the first linkage and the third pivot point of the second linkage does not rotate over-center with respect to the fourth pivot point of the second linkage as the back reclines from a fully upright position to a fully reclined position.

24. The chair of claim 23, wherein a centrode of the back with respect to the seat remains above the seat as the back reclines from the fully upright position to the fully reclined position.

25. The chair of claim 24, wherein the centrode substantially coincides with a hip point of a user sitting in the chair as the back reclines from the fully upright position to the fully reclined position.

26. The chair of claim 23, wherein the second pivot point and the third pivot point rise vertically throughout reclining of the back from the fully upright position to the fully reclined position.