Back construction with flexible lumbar

• US 20050275263A1
• Filed: 06/10/2004
• Published: 12/15/2005
• Est. Priority Date: 06/10/2004
• Status: Active Grant

• Current Assignee: Steelcase Incorporated
• Original Assignee: Steelcase Incorporated
• Inventors: Heidmann, Kurt R., Norman, Christopher J.
• Granted Patent: US 7,458,637 B2
• Time in Patent Office: Days
• US Class Current: 297/284.400
• CPC Class Codes: A47C 7/46 with special, e.g. adjustable , lumbar region support profile; "Ackerblom" profile chairs
• CPC Class Codes: A47C 7/467 adjustable by fluid means
• CPC Class Codes: A61G 5/12 Rests specially adapted therefor, e.g. for the head or the feet
• CPC Class Codes: B60N 2/667 having flexible support member bowed by applied forces
• CPC Class Codes: B60N 2/6673 with motor driven adjustments

Abstract

A back construction includes a back shell mounted on a back frame at top and bottom connections, and a flexible lumbar section biased forwardly by a biasing device. The bottom connection is located rearward of the back shell to allow unencumbered sliding entry into the seating unit from a lateral side position, but the bottom connection defines a virtual pivot forward of its physical location to provide the desired path of flexure when the lumbar section is flexed. In one form, the bottom connection is a pair of non-parallel links of dissimilar length. In another form, the bottom connection is a follower with two bearings following a guide slot. In some variations, the force of the biasing device is variable. Seating units incorporating the back construction include a vehicle seat, a foldable portable stadium seat, and a wheelchair seat.

Claims

1. A back construction for a seating unit, comprising:

a back frame; and

a back support including top and bottom connections operably supporting the back support on the back frame, the back support having a flexible lumbar region between the top and bottom connections, the bottom connection directing movement of a lower edge of the back support along a predetermined path as the lumbar region is flexed from a forwardly-protruding shape toward a more planar shape, the bottom connection being positioned rearward of and configured to not project in front of the lower edge of the back support, wherein the bottom connection comprises a linkage.

2. The back construction defined in claim 1, wherein the bottom connection is located rearward of the front surface of the sides of the lower edge in a location that reduces interference to a user sliding laterally onto the back support.

4. The back construction defined in claim 1, wherein the linkage includes at least one pair of cooperating links on each side of the back support.

5. The back construction defined in claim 4, wherein the pair of links are non-parallel and define an angle therebetween.

6. The back construction defined in claim 4, wherein the pair of links are similar in length.

7. The back construction defined in claim 4, wherein the back support also includes a biasing device that biases the back support causing the lumbar region to flex toward the forwardly-protruding shape.

10. The back construction defined in claim 1, wherein the back support has relatively rigid thoracic and pelvic regions located above and below the lumbar region, respectively, and wherein the lumbar region comprises a forwardly-protruding region connecting the thoracic and pelvic regions.

11. The back construction defined in claim 1, including a biasing device that biases the back support in a manner causing the lumbar region to flex toward the forwardly-protruding shape.

12. The back construction defined in claim 11, wherein the biasing device comprises a separate member.

13. The back construction defined in claim 11, wherein the biasing device is continually active and continuously biasing the lumbar region toward the forwardly-protruding shape.

14. The back construction defined in claim 11, wherein the biasing device is adjustable to provide an adjustable biasing force.

15. The back construction defined in claim 11, wherein the biasing device is operably attached between the back frame and the lower edge of the back support.

16. The back construction defined in claim 15, including an adjuster for adjusting a biasing force of the biasing device.

17. The back construction defined in claim 16, wherein the adjuster includes a guide on the back frame and includes a follower that slidably engages the guide, the biasing device being operably attached to the follower.

18. The back construction defined in claim 16, wherein the adjuster includes a powered mechanism for adjusting the biasing device.

19. The back construction defined in claim 11, wherein the biasing device comprises an extensible spring.

20. The back construction defined in claim 11, wherein the biasing device includes a pneumatic device.

21. The back construction defined in claim 1, wherein the back frame includes at least one forwardly-extending leg with a hook-shaped attachment section adapted to engage a support structure.

22. The back construction defined in claim 1, wherein the back frame includes forwardly extending lower legs having at least one pivot thereon, the legs being adapted for mounting to a mobile pedestal chair base.

23. A seating unit comprising a base and a seat, and also including the back construction defined in claim 1, the back construction being operably mounted on the base for reclining motion relative to the seat.

24. The seating unit defined in claim 23, wherein the base includes radially-extending castored legs for mobile rolling on a floor surface.

25. The seating unit defined in claim 23, wherein the base includes flanges for attachment to a vehicle body.

26. The seating unit defined in claim 25, wherein the seating unit comprises a vehicle seat with the back, the seat, and the back frame having suitable strength and construction for passing federal motor vehicle safety standards, including impact and crashworthiness test requirements.

27. The back construction defined in claim 1, wherein the back frame includes downwardly extending lower legs adapted to telescopingly engage mating structure on a base for supporting the back construction.

28. A wheelchair comprising a mobile base and a seat, and also including the back construction as defined in claim 1, the back construction being operably mounted on the mobile base for active lumbar supporting motion relative to the seat.

3. (canceled)

8. (canceled)

9. (canceled)

29. A seating unit comprising:

a base;

a seat;

a back frame; and

a back support including at least one top connection operably supporting the back support on the back frame and at least one bottom connection operably supporting the back support on one of the base and the back frame, the back support having a flexible lumbar region between the top and bottom connections, the bottom connection being constructed to direct movement of a lower edge of the back support generally downwardly along a predetermined path as the lumbar region is flexed from a forwardly-protruding shape toward a more planar shape, the bottom connection being positioned rearward of front surfaces along sides of the lower edge, wherein the at least one bottom connection includes at least one four-bar linkage.

31. The seating unit defined in claim 30claim 29, wherein the at least one four-bar linkage includes a pair of links on each side of the back support.

33. The seating unit defined in claim 29, wherein the base includes a pair of large rear wheels and angularly adjustable front wheels forming a wheelchair.

34. The seating unit defined in claim 29, wherein the base includes attachment flanges configured for attachment to a vehicle body, and wherein the base, seat, and back frame have suitable strength and construction for passing federal motor vehicle safety standards, including impact and crashworthiness test requirements.

35. The seating unit defined in claim 29, wherein the base includes radially extending legs and castors on the legs for rolling support on a floor surface.

30. (canceled)

32. (canceled)

36. A back construction for a seating unit, comprising:

a back frame; and

a back support including at least one top connection and at least one bottom connection operably supporting the back support on the back frame, the back support having a flexible lumbar region between the at least one top and bottom connections, at least one of the connections constraining movement of the back support along a predetermined path as the lumbar region is flexed from a forwardly-protruding shape toward a more planar shape, the one connection being positioned rearward of and configured to not project in front of the back support, wherein the at least one bottom connection includes a four-bar linkage.

38. The back construction defined in claim 36, wherein the four-bar linkage includes a pair of links on each side of the back support.

40. The back construction defined in claim 36, including a bottom leg configured for attachment to a vehicle body, and wherein the back frame has a suitable strength and construction for passing federal motor vehicle safety standards, including impact and crashworthiness test requirements.

41. The back construction defined in claim 36, wherein the back frame includes a rearwardly extending leg having a pivot thereon and is adapted for use in an office chair.

37. (canceled)

39. (canceled)

42. A seating unit comprising:

a seat;

a back frame;

a back support operably connected to the back frame at an upper connection and a lower connection, the back support having a flexible lumbar region generally between the upper and lower connections; and

the lower connection including a linkage arrangement having at least a pair of cooperating links adapted to constrain at least the lower portion of the back support to move along a predetermined path as the lumbar region is moved.

43. The seating unit defined in claim 42, wherein the bottom connections include a four-bar linkage.

44. The seating unit defined in claim 43, wherein the four-bar linkage includes a pair of links on each side of the back support.

46. The seating unit defined in claim 42, including a base having a pair of large rear wheels and angularly adjustable front wheels forming a wheelchair.

47. Currently amended) The seating unit defined in claim 42, including a base having attachment flanges configured for attachment to a vehicle body, and wherein the base, seat, and back frame have suitable strength and construction for passing federal motor vehicle safety standards, including impact and crashworthiness test requirements.

48. The seating unit defined in claim 42, including a base having radially extending legs and castors on the legs for rolling support on a floor surface.

49. Currently amended) The seating unit defined in claim 42, wherein the linkage arrangement extends rearward of the back support.

75. The seating unit defined in claim 42, wherein the lumbar region is flexible.

45. (canceled)

50. A seating unit comprising:

a seat;

a back frame;

a back support connected to the back frame at an upper connection and a lower connection, the back support having a lumbar region generally located between the upper and lower connections; and

the lower connection including a constraining mechanism located rearward of the forward face of the back support and adapted to constrain at least the lower portion of the back support to move and rotate along a predetermined path as the lumbar region is moved, wherein the bottom connections include a four-bar linkage.

52. The seating unit defined in claim 50, wherein the four-bar linkage includes a pair of links on each side of the back support.

54. The seating unit defined in claim 50, including a base having a pair of large rear wheels and angularly adjustable front wheels forming a wheelchair.

55. The seating unit defined in claim 50, including a base having attachment flanges configured for attachment to a vehicle body, and wherein the base, seat, and back frame have suitable strength and construction for passing federal motor vehicle safety standards, including impact and crashworthiness test requirements.

56. The seating unit defined in claim 50, including a base having radially extending legs and castors on the legs for rolling support on a floor surface.

76. The seating unit defined in claim 50, wherein the lumbar region is flexible.

51. (canceled)

53. (canceled)

57-64. -64. (canceled)

65. A back construction for a seating unit comprising:

a back frame;

a back support; and

at least one connection operably connecting to the back frame for movement relative to the back frame;

the at least one connection including a pair of spaced-apart cooperating links each with a first end connected to the back frame and each with a second end connected to the back support, the cooperating links being positioned and adapted to constrain a body-supporting portion of the back support to move along a predetermined path and, while moving along said path the body-supporting portion defining a predetermined vertical angle corresponding to each location along the predetermined path.

66. The back construction defined in claim 65, wherein at least some of the predetermined angles at each location are different than adjacent ones of the predetermined vertical angles.

67. The back construction defined in claim 65, wherein the predetermined path of the portion of the back support is non-linear non-arcuate.

68. The back construction defined in claim 65, wherein the first and second links have different lengths.

69. The back construction defined in claim 65, wherein the first and second links are elongated to define longitudinal axes that extend in non-parallel directions.

70. The back construction defined in claim 65, wherein the first and second ends of each of the first and second links define four axes of rotation, the four axes defining a first pattern that is different than a second pattern suitable for a parallelogram linkage arrangement.

71. The back construction defined in claim 65, wherein the at least one connection is positioned entirely behind a front surface of the back support.

72. The back construction defined in claim 65, wherein the at least one connection includes a second pair of cooperating links, the second pair of cooperating links being positioned on a side of the back support opposite the first-mentioned pair of cooperating links.

73. A seating unit comprising a base, a seat supported on the base, and the back construction defined in claim 65, the back frame being operably supported on the base for angular adjustment.

74. The back construction defined in claim 65, wherein the back support comprises a shell having a flexible lumbar region.