Chair

• US 6,588,845 B2
• Filed: 07/25/2002
• Issued: 07/08/2003
• Est. Priority Date: 06/10/1994
• Status: Expired due to Fees

• Current Assignee: Haworth Incorporated
• Original Assignee: Haworth Incorporated
• Inventors: Wilkerson, Larry A., Roslund, Richard N. Jr.
• Primary Examiner(s): WHITE, RODNEY BARNETT
• Application Number:
  US10/205,542
• Publication Number:
  US 20020190556A1
• Time in Patent Office: 348 Days
• Field of Search: 297/316, 297/301.7, 297/302.7, 297/300.2, 297/300.4, 297/344.19, 297/302.6
• US Class Current: 297/300.2
• CPC Class Codes: A47C 1/03255 with a central column, e.g. rocking office chairs
• CPC Class Codes: A47C 1/03261 characterised by elastic means
• CPC Class Codes: A47C 1/03272 with coil springs
• CPC Class Codes: A47C 1/03274 of torsion type
• CPC Class Codes: A47C 1/03277 with bar or leaf springs

Abstract

An office-type chair which provides for synchronous differential tilting of the seat and back assemblies, with the seat assembly being constructed such that the front lip thereof does not significantly lift upon rearward tilting. The chair incorporates a tilt control mechanism formed by a control body which secures to the upper end of the chair pedestal and an upright which pivotally connects to the control body about an axis disposed forwardly of the pedestal. A pivot assembly connects the upright and control body together.

Claims

1. In an office-type chair having a base, a cantilevered pedestal assembly projecting upwardly from substantially the center of said base, and a seat-back arrangement connected to an upper end of said pedestal assembly, said seat-back arrangement including a generally horizontally enlarged seat assembly and a back assembly projecting upwardly from and adjacent a rear edge of said seat assembly, said seat-back arrangement including a rear tilt control mechanism for permitting the back assembly to be vertically tilted rearwardly relative to the seat assembly about a generally horizontally extending pivot axis which projects transversely relative to the seat assembly, said tilt control mechanism including a control housing associated with the seat assembly and an upright which is disposed at least partially within the back assembly and is interconnected to the control housing by a pivot shaft assembly which defines said horizontal pivot axis, and a biasing means associated with the tilt control mechanism to normally urge the upright forwardly toward a normal upright position, comprising the improvement wherein:

said upright including a pair of sidewardly spaced and generally vertical first side walls which are respectively positioned adjacent a pair of sidewardly spaced and generally vertical second side walls provided on said control housing, said first and second side walls respectively having aligned first and second openings therethrough which are substantially coaxially aligned with said pivot axis;

said pivot shaft assembly including a one-piece elongate support shaft positioned so as to extend between and through the aligned first and second openings provided in said pairs of first and second side walls, said support shaft having a longitudinal axis which defines said pivot axis;

said pivot shaft assembly also including a pair of bearing sleeves exteriorly surrounding and mounted on said support shaft adjacent opposite ends thereof, said bearing sleeves being axially and nonrotatably secured to but removably mounted on the support shaft;

each said bearing sleeve including a first generally annular part which is nonrotatably supportingly engaged within one of said first openings and a second annular part which is rotatably supported within the respectively adjacent second opening, said first and second annular parts being axially and fixedly joined as an integral part of said bearing sleeve and having a bore projecting coaxially therethrough in which an end portion of said support shaft is supportingly engaged.

2. A chair according to claim 1, wherein each bearing sleeve has a resilient detent integrally associated therewith and resiliently engaged with the main support shaft to axially secure the support shaft relative to the respective bearing sleeve.

3. A chair according to claim 2, wherein the first and second annular parts are disposed adjacent one axial free end of said bearing sleeve, and wherein said bearing sleeve includes a third part which is axially elongated and projects axially away from said first and second annular parts and terminates in a free end, said third part being disposed between the pairs of first and second side walls, and said biasing means including a torsion spring which has a coil portion which is positioned between the pairs of side walls and has a coil portion which exteriorly surrounds the support shaft, said coil portion being supportingly engaged with said third bearing part.

4. A chair according to claim 2, wherein said first annular part includes a groove formed in an outer peripheral surface thereof for accommodating a rib on the respective side wall so as to axially secure the respective bearing sleeve to the respective side wall, and the opening in said respective side wall being oversized relative to the first annular part to permit limited transverse movement of the first annular part therein so that the first annular part of the bearing sleeve can be inserted into the respective opening and then moved transversely to engage the rib within the groove.

5. A chair according to claim 2, wherein the pair of bearing sleeves are identical and are each integrally constructed in one piece of a plastics material.

6. In an office-type chair having a base and a seat-back arrangement supported on said base, said seat-back arrangement including a seat, a back projecting upwardly from said seat, and a tilt control mechanism interconnecting said seat and said back so as to permit the back to tilt rearwardly relative to the seat about a generally horizontally extending pivot axis which extends transversely relative to the seat, said tilt control mechanism including a control body associated with the seat and an upright which is interconnected to the control body by a pivot assembly which defines said pivot axis, and including a biasing member associated with the tilt control mechanism to bias the upright forwardly toward a normal upright position, comprising the improvement wherein:

said upright includes a pair of sidewardly spaced first side walls which are respectively positioned in opposing relation with a pair of sidewardly spaced second side walls provided on said control body, said first and second side walls respectively having aligned first and second openings through which said pivot axis extends;

said pivot assembly further including bearing sleeves disposed within said first and second openings, each said bearing sleeve including a first support part which is nonrotatably supported within a respective one of said first openings and a second support part which is rotatably supported within a respective one of the second openings aligned with said respective first opening, said first and second support parts being axially fixed relative to each other wherein said upright is rotatably supported on said control body, said second support part including a groove which opens radially and fits on an edge of said respective first opening to axially locate said bearing sleeve relative to said first side walls of said upright.

7. A chair according to claim 6, wherein each of said bearing sleeves includes a bore projecting axially therethrough in which is received a horizontally elongate pivot shaft section.

8. A chair according to claim 7, wherein said pivot shaft sections of said bearing sleeves are fixed together to define an elongate pivot shaft which extends through all of said aligned bearing sleeves.

9. A chair according to claim 8, wherein said biasing member is supported on said pivot shaft so as to act on said control body and said upright and bias said upright to said normal upright position.

10. A chair according to claim 9, wherein said bearing sleeve includes a third support part which projects axially away from said first and second annular parts and is disposed within said biasing member to rotatably support said biasing member on said pivot shaft.

11. A chair according to claim 6, wherein said second opening is oversized relative to said first support part of said bearing sleeves to permit limited transverse movement of the first support part therein so that the first support part can be inserted into he respective first opening and move transversely to engage said edge of said first opening within said groove.

12. A chair according to claim 11, wherein said groove opens downwardly and said biasing member acts upwardly on said upright.

13. In an office-type chair having a base projecting upwardly and a seat-back arrangement connected to said base, said seat-back arrangement including a support body associated with said seat assembly and an upright which supports a back of said chair thereon and is interconnected to said support body by a pivot shaft assembly which defines a horizontal pivot axis about which said upright pivots, comprising the improvement wherein:

said upright and said support body include aligned first and second openings which are substantially coaxially aligned with said pivot axis, said pivot shaft assembly including an elongate support shaft positioned so as to extend between and through the aligned first and second openings;

said pivot shaft assembly also including a one-piece bearing sleeve exteriorly surrounding and mounted on said support shaft adjacent an end thereof, said bearing sleeve being axially and non-rotatably secured to said support shaft; and

each said bearing sleeve including a generally annular first part which is non-rotatable received within said first opening to support said pivot shaft therein and a generally annular second part which is rotatably supported within the respectively adjacent second opening and engages said upright to prevent axial movement of said upright relative to said support shaft, said first and second annular parts being integrally joined together axially adjacent to each other and having a bore projecting coaxially therethrough in which said support shaft is received.

14. A chair according to claim 13, wherein said first opening is larger than said first support part of said bearing sleeve to permit limited radial movement of said first support part therein so that said first support part is insertable into said respective first opening and movable radially to engage said edge of said first opening.

15. A chair according to claim 14, wherein said second support part includes a groove which opens radially and fits on an edge of said respective first opening to axially locate said bearing sleeve relative to said upright.

16. A chair according to claim 15, further including a biasing member which is supported on said support shaft and biases said upright to a normal upright position and resist tilting of said back away from said normal upright position, said biasing member acting upwardly on said upright while biasing said support shaft and bearing sleeve away therefrom to move said groove radially into engagement with said edge of said first opening.

17. In an office-type chair having a pedestal and a seat-back arrangement supported on said pedestal, said chair further including a base chair component, a movable chair component and a tilt mechanism interconnecting said base component and said movable component so as to permit the movable component to tilt about a pivot axis which extends horizontally and transversely relative to said base component, said tilt mechanism including a pivot assembly pivotally interconnecting said movable component and said base component together, said pivot assembly defining said pivot axis and permitting tilting of said movable component away from a normal upright position about said pivot axis, and said tilt mechanism further including a biasing member which biases said movable component toward the normal upright position, comprising the improvement wherein:

said movable and base components include aligned openings through which said pivot assembly extends horizontally to rotatably support said movable component on said base component;

said pivot assembly further including a bearing unit which extends through said aligned openings and has a cylindrical outer bearing surface, said bearing unit further including a grooved portion having a groove which opens radially and fits on an edge of one of said openings to axially locate said bearing unit relative to said base and movable components, said edge of said one opening being spaced radially from said grooved portion to permit radial displacement of said grooved portion and said one opening relative to each other such that said grooved portion fits axially into said one opening and is displaceable radially to engage said edge of said one opening within said groove, said biasing member acting on said movable component to bias said movable component toward the normal upright position and to effect displacement of said opening edge into engagement with said grooved portion.

18. A chair according to claim 17, wherein said bearing unit includes a bore projecting axially therethrough in which is received a horizontally elongate pivot shaft.

19. A chair according to claim 18, wherein said biasing member is supported on said pivot shaft so as to act on said base component and has a movable resilient portion which acts on said movable chair component to bias said movable component to said normal upright position.

20. A chair according to claim 19, wherein said bearing unit projects axially within said biasing member such that said biasing member is supported on said pivot shaft by said bearing unit.

21. In an office-type chair having a pedestal and a seat-back arrangement supported on said pedestal, said chair further including a base chair component, a movable chair component and a tilt mechanism interconnecting said base component and said movable component so as to permit the movable component to tilt about a pivot axis which extends horizontally and transversely relative to said base component, said tilt mechanism including a pivot assembly pivotally interconnecting said movable component and said base component together, said pivot assembly defining said pivot axis and permitting tilting of said movable component away from a normal upright position about said pivot axis, and said tilt mechanism further including a biasing member which biases said movable component toward the normal upright position, comprising the improvement wherein:

said movable and base components include aligned first and second openings through which said pivot assembly extends horizontally to rotatably support said movable component on said base component;

said pivot assembly further including a bearing unit which extends through said aligned openings and has a cylindrical outer bearing surface rotatably received within said second opening, said first opening being spaced radially from said bearing unit to permit displacement of said movable component such that said bearing unit fits axially into said first opening and said movable component is displaceable radially relative thereto, said bearing unit and said movable component including cooperating engagement parts which engage one with the other upon radial displacement of said movable component to prevent axial movement of said movable component relative to said bearing unit, said biasing member acting on said movable component to bias said movable component toward the normal upright position about said pivot axis and to effect radial displacement of said movable component by which said cooperating engagement parts are engaged.

22. A chair according to claim 21, wherein said cooperating engagement parts comprise a cooperating groove and an insert which fits within said groove in response to radial displacement of said movable component.

23. A chair according to claim 21, wherein said outer bearing surface fits within said second opening in close fitting engagement therewith.