Seating unit with reclineable back and forwardly movable seat

• US 6,394,549 B1
• Filed: 10/20/2000
• Issued: 05/28/2002
• Est. Priority Date: 10/24/1997
• Status: Expired due to Term

• Current Assignee: Steelcase Development Inc.
• Original Assignee: Steelcase Development Corporation (Steelcase Incorporated)
• Inventors: Heidmann, Kurt R., DeKraker, Larry, Knoblock, Glenn A., Teppo, David S.
• Primary Examiner(s): Nelson, Jr., Milton
• Application Number:
  US09/692,816
• Time in Patent Office: 585 Days
• Field of Search: 297/300.1,300.2,300.6,300.3,3.7,303.1,303.4,340-342
• US Class Current: 297/342
• CPC Class Codes: A47C 1/023 the parts being horizontally-adjustable seats ; Expandable seats or the like, e.g. seats with horizontally adjustable parts
• CPC Class Codes: A47C 1/03233 by means of a rack-and-pinion or like gearing mechanism
• CPC Class Codes: A47C 1/03238 by means of peg-and-notch or pawl-and-ratchet mechanism
• CPC Class Codes: A47C 1/03255 with a central column, e.g. rocking office chairs
• CPC Class Codes: A47C 1/03272 with coil springs
• CPC Class Codes: A47C 1/03274 of torsion type
• CPC Class Codes: A47C 7/14 of adjustable shape; elastically mounted ; adaptable to a user contour or ergonomic seating positions movably-coupled seat and backrests with elastic adjustment means A47C1/03261; elastically-mounted back-rests or backrest-seat units in the base frame A47C7/44
• CPC Class Codes: A47C 7/24 Upholstered seats A47C7/18 takes precedence
• CPC Class Codes: A47C 7/445 with bar or leaf springs
• CPC Class Codes: A47C 7/46 with special, e.g. adjustable , lumbar region support profile; "Ackerblom" profile chairs
• CPC Class Codes: Y10S 297/02 Molded

Abstract

A seating unit is provided having a base assembly with a particularly shaped housing and rigid upright side arms, a back frame pivoted to the base assembly for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. A flexible back is connected to the back frame at top and bottom locations and is provided with lumbar adjustment for improved lumbar force/support and shape. A seat is provided with seat depth adjustment and with active and passive thigh flex support. A novel energy mechanism is provided that includes a moment arm shift adjuster for adjusting the spring tension on the back frame. The moment arm shift adjuster is readily adjustable and includes an overtorque device to prevent damage to components of the energy mechanism.

Claims

1. A seating unit comprising:

a base assembly;

a back frame pivoted to the base assembly at a back pivot for movement between a plurality of positions including upright and reclined positions;

a seat pivoted to the back frame at a seat pivot spaced rearwardly and below the back pivot, the seat being slidably supported at a front portion of the base assembly for horizontal movement, the back pivot and the seat pivot being interconnected and arranged to move the seat generally forwardly and also move a rear portion of the seat downwardly with a synchronous pivoting motion as the back frame is reclined, whereby a seated user is comfortably supported in the upright and reclined positions;

the base assembly including a control housing with an energy mechanism positioned therein that operably engages one of the back frame and the seat for biasing the back frame to the upright position; and

the seat including a seat slide member that slidably engages the control housing, and further including a seat support carrier pivotally engaging the seat slide at first pivots and pivotally engaging the back frame at second pivots.

2. The seating unit defined in claim 1 wherein the energy mechanism includes a spring positioned transversely within the control housing, and further including a lever operably connecting the spring to one of the seat and the back frame.

3. The seating unit defined in claim 1 wherein the control housing includes opposing side flanges, and the seat includes bearings slidably engaging the side flanges.

4. The seating unit defined in claim 1 wherein the seat includes a seat support carrier slidably connected to the base assembly and pivotally connected to the back frame, and further includes a seat shell slidably supported on the seat support carrier for manually-adjustable depth adjustment.

5. The seating unit defined in claim 1 wherein the base assembly includes side arms that extend upwardly generally adjacent the seat for supporting the back frame and a portion of the seat.

6. The seating unit defined in claim 5 wherein the back frame is pivoted to the side arms.

7. The seating unit defined in claim 6 wherein the seat is pivoted to the back frame in a location generally proximate the side arms.

8. The seating unit defined in claim 1 wherein the seat includes a flexible seat shell having a rear section adapted to support buttocks of a seated adult user, and further includes a front section adapted to support thighs of the seated adult user and that is flexibly connected to the rear section, the rear section being carried and supported by the seat support carrier.

9. The seating unit defined in claim 8 wherein the seat further includes a spring resiliently supporting right and left sides of the front section for independent flexural movement to provide increased comfort for the seated user.

10. The seating unit defined in claim 8 wherein the seat further includes a releasable lockable gas spring operably adjustably supporting the front section for adjustable movement to provide adjustable comfort to the seated user.

11. The seating unit defined in claim 1 including a compliant back assembly attached to the back frame in at least two vertically-spaced locations, the compliant back assembly being constructed to flex between the at least two vertically-spaced locations to provide optimal lumbar support.

12. The seating unit defined in claim 11 wherein the compliant back assembly includes a resiliently flexible, one-piece shell.

13. The seating unit defined in claim 11 wherein the compliant back assembly includes a multi-piece assembly of components, each having a surface for supporting a portion of a human'"'"'s back.

14. The seating unit defined in claim 1, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

15. A seating unit comprising:

a base assembly;

a back frame pivoted to the base assembly at a back pivot for movement between a plurality of positions including upright and reclined positions;

seat pivoted to the back frame at a seat pivot spaced rearwardly and below the back pivot, the seat being slidably supported at a front portion of the base assembly for horizontal movement, the back pivot and the seat pivot being interconnected and arranged to move the seat generally forwardly and also move a rear portion of the seat downwardly with a synchronous pivoting motion as the back frame is reclined, whereby a seated user is comfortably supported in the upright and reclined positions;

the base assembly including a control housing with an energy mechanism positioned therein that operably engages one of the back frame and the seat for biasing the back frame to the upright position;

the base assembly including side arms that extend upwardly generally adjacent the seat for supporting the back frame and a portion of the seat;

the back frame being pivoted to the side arms;

the seat being pivoted to the back frame in a location generally proximate the side arms; and

the energy mechanism including a spring positioned transversely in the control housing, and including a lever operably connecting the spring to the one of the seat and the back frame.

16. The seating unit defined in claim 15 including an adjustment mechanism for adjusting the lever to vary a biasing force transmitted from the spring to the seat, the adjustment mechanism including the lever and defining an adjustable moment arm on the lever for adjustably biasing the back frame toward the upright position.

17. The seating unit defined in claim 15, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

18. A seating unit comprising:

a base assembly including a control housing;

a back pivoted to the base assembly for movement between upright and reclined positions;

a seat operably supported on the base assembly and connected to the back for movement between a substantially rearward position and a forward position;

the seat including a front portion that is slidably connected to the base assembly to move horizontally forwardly upon recline of the back so that a seated user'"'"'s legs are not undesirably lifted from a floor surface during recline;

the seat further including a rear portion flexibly connected to the front portion and that is operably connected to the back to move downwardly and forwardly upon recline so that the seated user is comfortably and posturally supported during recline with an angular synchronous movement of the seat and the back, and so that a maximum forward movement of the seat and maximum angular movement of the back are limited to strokes that keep the hands of a seated user relatively constant during recline;

a spring mechanism positioned transversely in the control housing, and further including a lever pivotally engaging the spring mechanism and operably connected to the seat for biasing the seat toward the rearward position and simultaneously biasing the back toward the upright position; and

the control housing including side arms, and wherein the seat includes bearings that slidably engage the side arms.

19. The seating unit defined in claim 18 wherein the seat includes a seat support carrier slidably supported on the base assembly and pivotally engaging the back, and further includes a seat shell that is manually depth adjustable on the seat support carrier.

20. The seating unit defined in claim 18 wherein the side arms pivotally support the back at a location at a rear of the seat where the axis is adapted to be generally aligned with a hip joint of the seated user.

21. The seating unit defined in claim 20 wherein the rear portion is configured and adapted to support the majority of an adult seated user'"'"'s weight, and the front portion is configured and adapted to flexibly and comfortably support the thighs of the adult seated user without lifting the legs of the adult seated user during recline of the back.

22. The seating unit defined in claim 18 wherein the spring mechanism includes a spring resiliently supporting the front portion of the seat for flexural movement to provide increased comfort for the seated user.

23. The seating unit defined in claim 22 wherein the seat further includes a releasable lockable gas spring operably adjustably supporting the front portion for adjustable movement to provide adjustable comfort to the seated user.

24. The seating unit defined in claim 18, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back and the seat define a mobile task chair.

25. A seating unit comprising:

a base assembly;

a back including a unitary back frame pivoted to the base assembly for movement as a unit between upright and reclined positions;

a seat operably supported on the base assembly and connected to the back frame for movement between a substantially rearward position and a forward position;

the seat including a front portion that is slidably connected to the base assembly to move horizontally forwardly upon recline of the back so that a seated user'"'"'s legs are not undesirably lifted from a floor surface during recline; and

the seat further including a rear portion flexibly connected to the front portion and that is operably connected to the back to move downwardly and forwardly upon recline so that the seated user is comfortably and posturally supported during recline with an angular synchronous movement of the seat and the back, and so that a maximum forward movement of the seat and maximum angular movement of the back are limited to strokes that keep the hands of a seated user relatively constant during recline.

26. The seating unit defined in claim 25, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

27. A seating unit comprising:

a base assembly including side arms;

a unitary back frame pivoted to the base assembly at back pivots for movement as a unit between a plurality of positions including upright and reclined positions; and

a seat pivoted to the back frame at seat pivots and slidably supported at a front portion of a seat assembly, the back frame including right and left configured end sections positioned on opposite sides of the seat and between the sides of the seat and associated ones of the side arms, the configured end sections supporting first pivot bearings at the seat pivots and second pivot bearings at the back pivots.

28. The seating unit defined in claim 27, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame, and the seat define a mobile task chair.

29. A seating unit comprising:

a base assembly including a control housing;

an energy source located within the control housing;

a seat operably supported on the base assembly for generally horizontal movement between forward and rearward positions, with the seat operably interconnected to said energy source;

a back support including a back shell and a back frame supporting the back shell, wherein the back frame includes a first pivot wherein the back frame is pivotally coupled to the base assembly for movement of the back support between upright and reclined positions, and a second pivot wherein the back frame is pivotally coupled to the seat;

wherein the energy source biases the back support into an upright position by urging the seat rearward, said rearward movement of the seat inducing the back support to rotate to a generally upright position at the first pivot; and

a variable back-stop mechanism supported on the base assembly and operably engaging the seat, the variable backstop mechanism being configured to concurrently stop the seat and stop recline of the back support at a plurality of selectable positions between the upright and reclined position.

30. The seating unit defined in claim 29 wherein the first pivot axis is located at a rear of the seat where the first pivot axis is adapted to be generally aligned with a hip joint of a seated adult user.

31. The seating unit defined in claim 29 wherein the seat comprises a seat front slide adapted to slide forward and rearward on the control housing, a seat carrier pivotally interconnected to said control housing and said front slide, a seat frame in sliding engagement with said seat carrier, and a seat shell adapted to support a seated adult user.

32. The seating unit defined in claim 31 wherein the seat shell includes a rear section configured to support the seated adult user and to support a majority of the seated adult user'"'"'s weight, and further includes a front section adapted to support the thighs of a seated adult user, and still further includes a flexible zone connecting the rear section and the front section, and including an adjustment device connected to the front section and configured to angularly adjust the front section of the seat shell relative to the rear section, wherein the adjustment device is attached to an underside of the front section of the seat shell.

33. The seating unit defined in claim 29, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

34. A seating unit comprising:

a base assembly;

a back frame pivoted to the base assembly at a back pivot for movement between a plurality of positions including upright and reclined positions;

a seat pivoted to the back frame at a seat pivot spaced rearwardly and below the back pivot, the seat being slidably supported at a front portion of the base assembly for horizontal movement, the back pivot and the seat pivot being interconnected and arranged to move the seat generally forwardly and also move a rear portion of the seat downwardly with a synchronous pivoting motion as the back frame is reclined, whereby a seated user is comfortably supported in the upright and reclined positions;

the base assembly including a control housing with an energy mechanism positioned therein that operably engages one of the back frame and the seat for biasing the back frame to the upright position; and

a back-stop mechanism attached to the control housing and configured to selectively engage the seat to limit forward movement of the seat and accordingly selectively limit recline of the back frame.

35. The seating unit defined in claim 34, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

36. A seating unit comprising:

a base assembly;

a back frame pivoted to the base assembly at a back pivot for movement between a plurality of positions including upright and reclined positions;

a seat pivoted to the back frame at a seat pivot spaced rearwardly and below the back pivot, the seat being slidably supported at a front portion of the base assembly for horizontal movement, the back pivot and the seat pivot being interconnected and arranged to move the seat generally forwardly and also move a rear portion of the seat downwardly with a synchronous pivoting motion as the back frame is reclined, whereby a seated user is comfortably supported in the upright and reclined positions;

the base assembly including a control housing with an energy mechanism positioned therein that operably engages one of the back frame and the seat for biasing the back frame to the upright position;

wherein the energy mechanism includes a spring positioned transversely within the control housing; and

a lever operably connecting the spring to one of the seat and the back frame, the lever being pivotable about a vertical axis with a first end engaging the spring and a second end operably connected to the seat for biasing the seat rearwardly and in turn for biasing the back frame to the upright position.

37. The seating unit defined in claim 36, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

38. A seating unit comprising:

a base assembly;

a unitary back frame pivoted to the base assembly at a back pivot for movement as a unit between a plurality of positions including upright and reclined positions; and

a seat pivoted to the back frame at a seat pivot spaced rearwardly and below the back pivot, the seat being slidably supported at a front portion of the base assembly for horizontal movement, the back pivot and the seat pivot being interconnected and arranged to move the seat generally forwardly and also move a rear portion of the seat downwardly with a synchronous pivoting motion as the back frame is reclined, whereby a seated user is comfortably supported in the upright and reclined positions.

39. The seating unit defined in claim 38, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

40. A seating unit comprising:

a base assembly including a control housing;

an energy source located within the control housing;

a seat operably supported on the base assembly for generally horizontal movement between forward and rearward positions, with the seat operably interconnected to said energy source;

a back support including a back shell and a unitary back frame supporting the back shell, wherein the back frame includes a first pivot wherein the back frame is pivotally coupled to the base assembly for movement as a unit between upright and reclined positions, and a second pivot wherein the back frame is pivotally coupled to the seat; and

wherein the energy source biases the back support into an upright position by urging the seat rearward, said rearward movement of the seat inducing the back support to rotate to a generally upright position at the first pivot.

41. The seating unit defined in claim 40, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

42. A seating unit comprising:

a base assembly including a control housing and upwardly-extending side arms;

an inverted U-shaped back frame having configured end sections positioned adjacent associated ones of the side arms and pivoted thereto at back pivots, the back pivots each comprising a first stud and a rotatable first bearing engaging the first stud;

a seat slidably supported on the control housing, the seat including a seat carrier pivoted to the configured end sections at seat pivots, the seat pivots each comprising a second stud and a rotatable second bearing engaging the second stud, the seat pivots and back pivots being spaced apart; and

an adjustable energy mechanism including a transverse spring, a lever operably engaging the spring and the seat for biasing the seat toward a rearward position and in turn biasing the back frame toward an upright position, and an adjustment pivot member adjustably engaging the lever to define a fulcrum that moves during recline and that is manually adjustably changeable to relocate the fulcrum for adjustably controlling a force of the spring on the seat.

43. The seating unit defined in claim 42, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

44. A seating unit comprising:

a base assembly including a control housing;

an energy source located within the control housing;

a seat operably supported on the base assembly for generally horizontal movement between forward and rearward positions, with the seat being operably interconnected to said energy source, the seat including a seat shell having a rear section adapted to support buttocks of a seated adult user and a front section adapted to support thighs of the seated adult user; and

a back support including a back shell and a unitary back frame supporting the back shell, the back frame including a first pivot wherein the back frame is pivotally coupled to the base assembly for movement as a unit, and a second pivot point wherein the back frame is pivotally coupled to the seat.

45. The seating unit defined in claim 44, wherein the base assembly includes castors adapted to rollingly engage a floor surface, and wherein the base assembly, the back frame and the seat define a mobile task chair.

46. A seating unit comprising:

a base assembly;

a back frame pivoted to the base assembly at a back pivot for movement between a plurality of positions including upright and reclined positions;

a seat pivoted to the back frame at a seat pivot spaced below the back pivot, the seat being slidably supported at a front portion of the base assembly for generally horizontal movement, the back pivot and the seat pivot being interconnected and arranged to move the seat generally forwardly and also move a rear portion of the seat downwardly relative to a front portion of the seat with a synchronous pivoting motion as the back frame is reclined;

the base assembly including a control housing with an energy mechanism positioned therein that operably engages one of the back frame and the seat for biasing the back frame to the upright position; and

,

the seat including a seat slide member that slidably engages the control housing, and further including a seat support carrier pivotally engaging the seat slide at first pivots and pivotally engaging the back frame at second pivots.

47. The seating unit defined in claim 46 wherein the seat pivot is spaced rearwardly of the back pivot.

48. The seating unit defined in claim 46 wherein the seat is coupled to the back frame so that a rear portion of the seat moves downward relative to the base assembly during recline of the back frame.