U.S. patent application number 11/919377 was filed with the patent office on 2010-01-14 for chair back.
Invention is credited to Steve Gager, Eric Johnson, Wesley D. Mersman, Larry A. Wilkerson, Joe Willette.
Application Number | 20100007190 11/919377 |
Document ID | / |
Family ID | 36580396 |
Filed Date | 2010-01-14 |
United States Patent
Application |
20100007190 |
Kind Code |
A1 |
Johnson; Eric ; et
al. |
January 14, 2010 |
Chair back
Abstract
An office chair (10) is provided-having a contoured back
assembly (24) comprising a back frame (23) and a suspension fabric
(26). The fabric is attached to the back frame through a spline
(58) wherein the back frame has a three-dimensional contoured shape
formed by overlapped frame rings with the fabric being joined
thereto by a spline. The back frame has a split upright section to
increase the ability of the left and right halves of the frame to
articulate relative to each other. Further, a bayonet connection is
provided between the back frame and a support upright which bayonet
connection holds together the upper ends of two separate uprights
of a tilt control mechanism.
Inventors: |
Johnson; Eric; (Hudsonville,
MI) ; Gager; Steve; (Holland, MI) ; Mersman;
Wesley D.; (Holland, MI) ; Willette; Joe;
(Grand Haven, MI) ; Wilkerson; Larry A.; (Comstock
Park, MI) |
Correspondence
Address: |
FLYNN, THIEL, BOUTELL & TANIS, P.C.
2026 RAMBLING ROAD
KALAMAZOO
MI
49008-1631
US
|
Family ID: |
36580396 |
Appl. No.: |
11/919377 |
Filed: |
March 1, 2006 |
PCT Filed: |
March 1, 2006 |
PCT NO: |
PCT/US2006/007819 |
371 Date: |
September 25, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60657313 |
Mar 1, 2005 |
|
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|
Current U.S.
Class: |
297/440.15 |
Current CPC
Class: |
A47C 7/40 20130101; A47C
31/023 20130101 |
Class at
Publication: |
297/440.15 |
International
Class: |
A47C 7/00 20060101
A47C007/00 |
Claims
1. A chair comprising: a seat assembly; and a back assembly
supported rearwardly adjacent to said seat assembly, said back
assembly comprising a peripheral back frame which projects upwardly
above said seat assembly and defines an open area; and said back
assembly further including a suspension fabric which overlies said
open area and has a periphery connected to a corresponding
periphery of said back frame, said back frame comprising front and
rear frame sections which fit one over the other in facing relation
and are fixed together wherein said peripheral edge of said back
frame comprises a peripheral spline channel extending about the
interface between said front and rear frame sections, said spline
channel opening outwardly and adapted to receive said peripheral
edge of said suspension fabric therein, said back frame further
including an elongate spline which engages said periphery of said
suspension fabric and is press-fitted into said spline channel in
non-removable engagement therewith, said front and rear frame
sections defining respective front and rear channel walls of said
spline channel wherein said spline maintains said suspension fabric
in a taut condition.
2. The chair according to claim 1, wherein said front and rear
frame sections include opposing interior faces which define said
front and rear channel walls.
3. The chair according to claim 1, wherein said front and rear
frame sections are contoured molded frames having a contour such
that said opposing interior faces of said front and rear frame
sections of a three-dimensional shape such that each of said
interior faces is curved.
4. The chair according to claim 3, wherein said spline is
longitudinally elongate and has a uniform cross-sectional
shape.
5. The chair according to claim 3, wherein said spline is fastened
to said peripheral edge of said suspension fabric by fastening
means and has a generally flat cross-sectional shape laying flat
against an opposing face of said fabric.
6. The chair according to claim 5, wherein said spline is formed of
a pair of U-shaped spline sections which each have an initial
U-shape and are provided with corner reliefs so that said spline
sections are folded over into an inverted U-shape and said inverted
spline sections are press-fitted into said spline channel.
7. A chair comprising: a seat assembly; and a back assembly
supported rearwardly adjacent to said seat assembly, said back
assembly comprising a peripheral back frame which projects upwardly
above said seat assembly and defines an open area; said back
assembly further including a suspension fabric which overlies said
open area and has a periphery connected to a corresponding
periphery of said back frame, said back frame comprising front and
rear frame sections which fit one over the other in facing relation
and are fixed together wherein said peripheral edge of said back
frame comprises a peripheral spline channel extending about the
outer periphery of the interface between said front and rear frame
sections, said spline channel opening outwardly and adapted to
receive said peripheral edge of said suspension fabric therein,
said back frame further including an elongate spline which is
contained within an edge portion of said periphery of said
suspension fabric and is press-fitted into said spline channel in
non-removable engagement therewith, said front and rear frame
halves defining respective front and rear wall sections of said
spline channel wherein said spline maintains said suspension fabric
in a taut condition; said front and rear frame sections being
individually molded frames having a three-dimensional contour which
defines opposing interior faces that abut against each other when
said front and rear frame sections are joined together, said
interior frame faces also having a three-dimensional contour such
that each of said interior faces is curved.
8. The chair according to claim 7, wherein said interior faces abut
in continuous contact with each other about the periphery of said
back frame.
9. The chair according to claim 8, wherein said fabric is affixed
continuously about the periphery thereof to the corresponding
periphery of said back frame.
10. The chair according to claim 9, wherein said suspension fabric
is stretched to a taut condition when said periphery of said fabric
is joined to said spline channel.
11. A chair comprising: a seat assembly comprising a seat frame; a
back assembly supported on said seat frame so as to project
upwardly therefrom, said back assembly comprising a back frame
which joins to said seat frame and has an annular frame shape which
defines an open region that is covered by a back fabric which
overlies this open region, said peripheral frame being supported on
said seat frame by a column structure comprising an upright support
column having a lower end joined to said seat frame by a base
connector such that said support column is supported in
cantilevered relation with respect to said seat frame, an upper end
portion of said support column including transverse column arms
which extend sidewardly from said support column and have outer
sideward ends which are joined to said peripheral frame
intermediate the upper and lower edges of said peripheral frame,
said support column having separated left and right column halves
which each support a respective one of said transverse arms thereon
such that said column halves and said arms are movable separate
from each other at the upper end portion of said support column
while said column halves are joined together at the bottom end of
said support column proximate to said base connector, said column
halves permitting separate movement of said back frame on the left
and right sides thereof.
12. The chair according to claim 11, wherein said left and right
column halves are separated from each other by a vertical slot
extending along a major length of said support column.
13. The chair according to claim 12, wherein said column halves are
supported in cantilevered relation by the bottom end of said
support column.
14. The chair according to claim 11, wherein said transverse arms
are joined to said peripheral frame approximately midway between
said upper and lower frame edges of said frame.
15. The chair according to claim 14, wherein a connector web
extends between the bottom edge of said back frame and said support
column to restrain movement of the bottom edge of said frame
relative to the movement of said upper edge of said frame.
16. A chair comprising: a seat assembly comprising a seat frame; a
back assembly supported on said seat frame so as to project
upwardly therefrom, said back assembly comprising a back frame that
is joined to said seat frame by a base connector and has an annular
frame shape which defines an open region which is covered by a back
fabric overlying the open region, said back fabric being joined to
said seat frame about the respective peripheries thereof so as to
support a back of a chair occupant, wherein said base connector is
a bayonet connector which projects downwardly and has a tapered
shape which tapers inwardly in the downward direction; and said
seat frame comprising an upright having a front end joined to said
seat frame and a rearward end which extends rearwardly and joins to
said bayonet connector of said back frame, said upright comprising
separate frame sections on opposite sides of said chair which have
respective front ends joined to said seat frame and respective
rearward ends which converge towards each other and abut against
each other to define a connector hub, said connector hub comprising
an upward opening socket in which said bayonet connector is
slidably received and fixedly joined thereto.
17. The chair according to claim 16, wherein said socket is defined
partially by each of said rearward ends of said frame sections.
18. The chair according to claim 16, wherein said hub has a left
hub half and a right hub half which are defined respectively by
said rearward ends of said frame sections.
19. The chair according to claim 18, wherein said hub halves
terminate at opposing inside hub faces and have rib sections
projecting inwardly into said socket at said opposing hub faces,
said bayonet connection including corresponding slotted portions
which extend vertically and receive said rib sections of said hub
therein to draw said hub halves sidewardly together and rigidly
join said frame sections together at said rearward ends
thereof.
20. The chair according to claim 18, wherein said cooperating slots
and ribs are tapered such that downward insertion of said bayonet
connector draws said hub halves sidewardly together in close,
abutting relation.
21. The chair according to claim 20, wherein a fastener is provided
which projects upwardly through said hub into fixed engagement with
said bayonet connector to displace said bayonet connector
downwardly into said socket which draws said bayonet connector and
said hub vertically together and draws said rearward ends of said
frame sections sidewardly together.
22. The chair according to claim 16, wherein a fastener is provided
which projects upwardly through said hub into fixed engagement with
said bayonet connector to displace said bayonet connector
downwardly into said socket which draws said bayonet connector and
said hub vertically together and draws said rearward ends of said
upright sections sidewardly together.
23. A chair comprising: a seat assembly comprising a seat frame;
and a back assembly supported on said seat frame so as to project
upwardly therefrom, said back assembly comprising a back frame
which joins to said seat frame and has an annular frame shape which
defines an open region that is covered by a back suspension fabric
which overlies this open region, said back fabric being joined to
said seat frame about the respective peripheries thereof so as to
support a back of a chair occupant, said back assembly further
including a cushion which is mountable on said back frame, said
cushion including a cushioned pad and pockets formed at upper and
lower edges thereof wherein said upper and lower pockets fit over
respective upper and lower edges of said back frame to join said
cushion to said back frame, said cushion pad overlying said
suspension fabric wherein said suspension. fabric supports loads
applied to said back frame by an occupant body and said cushion pad
overlies said suspension fabric to improve the comfort of a chair
occupant.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/657,313, filed Mar. 1, 2005.
FIELD OF THE INVENTION
[0002] The invention relates to an office chair with an improved
chair back and more particularly, to a chair back with a peripheral
frame and a suspension fabric secured thereto.
BACKGROUND OF THE INVENTION
[0003] Preferably, conventional office chairs are designed to
provide significant levels of comfort and adjustability. Such
chairs typically include a base which supports tilt control
assembly to which a seat assembly and back assembly are movably
interconnected. The tilt control mechanism includes a back upright
which extends rearwardly and upwardly and supports the back
assembly rearwardly adjacent to the seat assembly. The tilt control
mechanism serves to interconnect the seat and back assembly so that
they may tilt rearwardly together in response to movements by the
chair occupant and possibly to permit limited forward tilting of
the seat and back. Further, such chairs typically permit the back
to also move relative to the seat during such rearward tilting.
[0004] The back assembly of such office chairs may have a variety
of constructions wherein one type of construction includes an
annular back frame which defines an open interior in which the
chair occupant's back is supported. This central open area is
enclosed by a suspension mesh which spans the opening and has the
outer peripheral edge thereof affixed to the annular frame.
[0005] The back frame further has a section thereof rigidly
connected to an upright of the chair. The upright is connected to a
tilt control mechanism, which mechanism supports the seat assembly
and governs rearward tilting of the upright. As such, the back
assembly moves in combination with the upright when the occupant
reclines within the chair.
[0006] It is an object of the invention to provide an office chair
having a chair back arrangement which is improved relative to prior
chair back constructions.
[0007] Therefore, the invention relates to an office chair and more
particularly, to the construction of a chair back assembly and the
mounting of this chair back assembly to an upright.
[0008] The back assembly comprises an annular frame having a
suspension fabric which spans the central opening of the back and
has the periphery of the suspension fabric connected to the frame.
Preferably, the suspension fabric comprises a single layer of
suspension material which connects to the frame by a plastic spline
that is press fitted into an annular spline channel formed about
the periphery of the back frame.
[0009] The back frame is defined by side frame rails, which extend
vertically, and transverse cross rails, which extend horizontally
between the side rails at the top and bottom thereof. The back
frame has a contoured shape wherein the side frame rails curve
rearwardly and outwardly in the side-to-side direction, while the
cross rails also curve in the front-to-back direction to provide a
contoured shape for the back frame that comfortably conforms to the
chair back of the chair occupant.
[0010] To form the spline channel, the back frame is constructed of
molded front and back ring sections which are grooved about their
respective peripheries to define front and rear channel portions.
The front channel portion defines the front wall of the spline
channel while the rear channel portion defines the rear channel
wall. The front and rear ring sections overlie each other in
opposing relation and are rigidly secured together by suitable
fastening means such as ultrasonic welding, adhesives or even
threaded fasteners. When the two frame sections are rigidly joined
together, the grooved portions align with each other and define the
spline channel. In this manner, complex contours may be formed in a
molded back frame while still permitting the formation of a spline
channel about the periphery thereof.
[0011] Once the frame is assembled, the suspension fabric is
fastened to the frame by a spline which is press fitted into the
spline channel and traps the edge portions of the suspension fabric
within this channel.
[0012] The back frame also has an upright frame column which
extends into the central opening of the chair and terminates at its
upper end in transverse support arms which extend outwardly and are
rigidly affixed to the middle of the side frame members to thereby
provide further support to the back frame. The lower end of the
support column rigidly joins to the upright while the remainder of
the support column has a vertically elongate slot which separates
the support column into left and right halves. Since the back frame
flexes during use as a result of loads applied thereto when the
occupant leans against the back assembly, this separation slot
provides for increased independent movement of the upper corners of
the chair back relative to the other.
[0013] The lower end of the support column also includes an
improved bayonet connection which rigidly joins the back frame to
the uprights.
[0014] In particular, the uprights are formed as independent arms
which are each independently connected to the tilt control
mechanism and move together in unison. The rearmost ends of the
uprights are disposed adjacent to each other and define a connector
hub with an upward opening socket into which the bayonet connector
is slidably inserted. Each upright defines one-half of the socket
and includes ribs projecting into the socket that are then slidably
received within a corresponding tapered slot of the bayonet
connector wherein this connector slot of the bayonet connector
serves to hold the rear ends of the upright sidewardly together and
prevent separation thereof. A further fastener is provided
vertically between the upright hub and the back frame to draw these
components vertically together such that the separate uprights are
rigidly held together by the bayonet connector and as such move
together in unison.
[0015] The foregoing features provide an improved back frame
arrangement, wherein other objects and purposes of the invention,
and variations thereof, will be apparent upon reading the following
specification and inspecting the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a front elevational view of an office chair having
an inventive back assembly arrangement.
[0017] FIG. 2 is a side elevational view of the office chair.
[0018] FIG. 3 is a rear isometric view thereof.
[0019] FIG. 4 is a front isometric view thereof.
[0020] FIG. 5 is a side view of a back assembly.
[0021] FIG. 6 is a front view thereof.
[0022] FIG. 7 is an exploded isometric view of the back assembly
with a fastener for mounting the back frame on the tilt control
mechanism of the chair.
[0023] FIG. 8 is an enlarged exploded view of the mounting section
of the back frame.
[0024] FIG. 9 is an exploded isometric view of the back components
forming the back assembly.
[0025] FIG. 10 is a side cross-sectional view of the back assembly
as taken along the centerline of the back assembly.
[0026] FIG. 11 is a rear view of the back frame.
[0027] FIG. 12 is a front view of the back frame.
[0028] FIG. 13 is a diagrammatic view illustrating the manufacture
of sheets of suspension fabric from a stock material.
[0029] FIG. 14 is a top cross-sectional view of a side frame member
as taken along line 14-14 of FIG. 6.
[0030] FIG. 15 is a side cross-sectional view of the top frame
member as taken along line 15-15 of FIG. 6.
[0031] FIG. 16 is a side cross-sectional view of the bottom frame
member as taken along line 16-16 of FIG. 6.
[0032] FIG. 17 is a front view of a cushion adapted for mounting to
the back assembly over the suspension fabric.
[0033] FIG. 18 is an exploded isometric view of the cushion
components.
[0034] FIG. 19 is an enlarged side cross-sectional view of the
bottom frame member with a bayonet connection along with a pelvic
support member mounted to the bottom frame member.
[0035] FIG. 20 is an enlarged, partial front view of the back
frame.
[0036] FIG. 21 is a rear view of the pelvic support.
[0037] FIG. 22 is a side view of the pelvic support.
[0038] FIG. 23 is a side cross-sectional view of the pelvic
support.
[0039] FIG. 24 is an enlarged partial isometric view of the back
assembly, seat assembly and tilt control mechanism.
[0040] FIG. 25 is an enlarged rear view of the bayonet
connector.
[0041] FIG. 26 is an enlarged side view of the bayonet
connector.
[0042] FIG. 27 is a top cross-sectional view of the bayonet
connector as taken along line 27-27 of FIG. 26.
[0043] FIG. 28 is a top cross-sectional view of the bayonet
connector as taken along line 28-28 of FIG. 26.
[0044] FIG. 29 is an interior side view of a support upright.
[0045] FIG. 30 is a front view of the upright.
[0046] FIG. 31 is a top cross-sectional view of a hub section of
the upright as taken along line 31-31 of FIG. 29.
[0047] FIG. 32 is a top cross-sectional view of the hub section as
taken along line 32-32 of FIG. 29.
[0048] FIG. 33 is a top cross-sectional view of the bayonet
connector seated within a socket defined by a hub of the
uprights.
[0049] FIG. 34 is an exploded isometric view of the second
embodiment of a back assembly.
[0050] FIG. 35 is a top cross-sectional view of the back frame of
the second embodiment of FIG. 34.
[0051] FIG. 36 is an isometric view of the suspension fabric
assembly for covering the back frame.
[0052] FIG. 37 is a front view of a spline adapted for attachment
to a suspension fabric of FIG. 36.
[0053] FIG. 38 is a top view of a first spline section.
[0054] FIG. 39 is a top view of a second spline section.
[0055] Certain terminology will be used in the following
description for convenience and reference only, and will not be
limiting. For example, the words "upwardly", "downwardly",
"rightwardly" and "leftwardly" will refer to directions in the
drawings to which reference is made. The words "inwardly" and
"outwardly" will refer to directions toward and away from,
respectively, the geometric center of the arrangement and
designated parts thereof. Said terminology will include the words
specifically mentioned, derivatives thereof, and words of similar
import.
DETAILED DESCRIPTION
[0056] Referring to FIGS. 1-4, the invention generally relates to
an office chair 10 which includes various inventive features
therein which accommodate the different physical characteristics
and comfort preferences of a chair occupant and also improve the
assembly of the chair 10.
[0057] Generally, this chair 10 includes improved height-adjustable
arm assemblies 12 which are readily adjustable. The structure of
each arm assembly 12 is disclosed in U.S. Provisional Patent
Application Ser. No. 60/657,632, filed Mar. 1, 2005, entitled ARM
ASSEMBLY FOR A CHAIR, which is owned by Haworth, Inc., the common
assignee of this present invention. The disclosure of this patent
application is incorporated herein in its entirety by
reference.
[0058] The chair 10 is supported on a base 13 having radiating legs
14 which are supported on the floor by casters 15. The base 12
further includes an upright pedestal 16 which projects vertically
and supports a tilt control mechanism 18 on the upper end thereof.
The pedestal 16 has a pneumatic cylinder therein which permits
adjustment of the height or elevation of the tilt control mechanism
18 relative to a floor.
[0059] The tilt control mechanism 18 includes a control body 19 on
which a pair of generally L-shaped uprights 20 are pivotally
supported by their front ends. The uprights 19 converge rearwardly
together to define a connector hub 22 on which is supported the
back frame 23 of a back assembly 24. The structure of this tilt
control mechanism is disclosed in U.S. Provisional Patent
Application Ser. Nos. 60/657,541, filed Mar. 1, 2005 and
60/689,723, filed Jun. 10, 2005, both entitled TILT CONTROL
MECHANISM FOR A CHAIR, and U.S. Provisional Patent Application Ser.
No. 60/657,524, filed Mar. 1, 2005, entitled TENSION ADJUSTMENT
MECHANISM FOR A CHAIR, which applications are owned by Haworth,
Inc. The disclosure of each of these patent applications is
incorporated herein in its entirety by reference.
[0060] The back assembly has a suspension fabric 25 supported about
its periphery on the corresponding periphery of the frame 23 to
define a suspension surface 26 against which the back of a chair
occupant is supported.
[0061] To provide additional support to the occupant, the back
assembly 24 also includes a lumbar support assembly 28 which is
configured to support the lumbar region of the occupant's back and
is adjustable to improve the comfort of this support. The structure
of this lumbar support assembly 28 and pelvic support structure is
disclosed in U.S. Provisional Patent Application Ser. No.
60/657,312, filed Mar. 1, 2005, entitled CHAIR BACK WITH LUMBAR AND
PELVIC SUPPORTS, which is also owned by Haworth, Inc. The
disclosure of this patent application is incorporated herein in its
entirety by reference.
[0062] Additionally, the chair 10 includes a seat assembly 30 that
defines an upward facing support surface 31 on which the seat of
the occupant is supported.
[0063] More particularly as to the back assembly 24, the back
assembly 24 is generally illustrated in FIGS. 5-7. The back frame
23 comprises a pair of vertical side frame rails 35, a top frame
rail 36, and a bottom frame rail 37 which are joined together at
the upper corners 38 of the back assembly 24 as well as the lower
corners 39 to define an annular or endless frame having a central
opening 40.
[0064] As can be seen in FIGS. 5-7, the back frame 23 has a
contoured shape which ergonomically supports the back of the user.
In particular, the side rails 35 curve backwardly as seen in FIGS.
5 and 7 as well as outwardly (FIG. 6) relative to the bottom
portions of the side rails 35. Further, the top rail 36 and bottom
rail 37 each have a respective curvature to closely conform to the
curvature of a typical chair occupant.
[0065] To support the occupant, the back assembly 24 includes the
suspension fabric 25 which is secured taughtly on the frame.
Specifically, the back frame 23 includes a peripheral spline
channel 42, in which is fixed the peripheral edge of the suspension
fabric 25 as will be discussed in further detail herein.
[0066] The back frame 23 also generally includes a support
structure 43 to which the side rails 35 and bottom rail 37 are
rigidly interconnected. This support structure 43 comprises an
upright support column 44 which extends along the chair centerline
41 (FIG. 7) to an elevation located just below the middle of the
side rails 35. The upper end of the support column 44 includes a
pair of support arms 45 which extend sidewardly and have each
respective outer end connected rigidly to one of the side rails
35.
[0067] The lower end of the support column 43 includes a generally
L-shaped connector flange 46 (FIGS. 5 and 7) which projects
forwardly and then downwardly into fixed engagement with the lower
cross rail 37. Still further, this lower column end includes a
bayonet connector 49 which projects downwardly for rigid connection
to the uprights 20 by fastener bolt 50 and nut 51 as will be
described in further detail hereinafter.
[0068] Referring more particularly to the components of the back
assembly 24, FIG. 9 illustrates these components in an exploded
view thereof. In particular, the frame 23 comprises a molded rear
frame unit 55 that includes the support structure 44 described
above as well as a rear frame ring 56 which is supported on the
support arms 45 of the support structure 44. The back frame 24
further includes a molded front frame ring 57 which is adapted to
be mounted to the rear frame ring 56 in overlying relation to
define the spline channel 42 about the periphery thereof. Further,
the back assembly 24 includes the above-described suspension fabric
25 and an elastomeric spline 58.
[0069] Referring to FIGS. 11 and 12, the rear frame unit 55
comprises the support structure 43 and the rear frame ring 56. Both
the support structure 43 and the rear frame ring 56 are molded
simultaneously together in a one-piece monolithic construction
having the contoured shape described above. To facilitate molding
of this contoured shape while still possessing the spline channel
42 mentioned above, the rear frame ring 56 and front frame ring 57
are molded separate from each other and then affixed together.
[0070] Turning to the support structure 43, the support column 44
thereof is located centrally within the lower half of the central
frame opening 40. The support column 44 has a base end 59 and a
pair of column halves 60 and 61 which are separated from each other
by a vertically elongate column slot 62. The column 44 therefore is
formed as a split column by the slot 62 which extends along a
substantial portion of the length of the column 44 with the column
halves 60 and 61 being joined together by the solid base section
59. As such, the column halves 60 and 61 are supported in
cantilevered relation by the base section 59. The rear frame unit
55 and front frame ring 57 are formed from a glass filled nylon
material that is molded into the desired shapes wherein this
material has limited flexure so as to permit flexing of the various
areas of the frame when placed under load by a chair occupant.
Since the column halves 60 and 61 are separated from each other by
the slot 62, these column halves 60 and 61 may articulate
independently of each other to facilitate flexing and movement of
the various frame corners 38 and 39.
[0071] The upper ends of the frame halves 60 and 61 join integrally
to the transverse arms 45. The outer ends of the arms 45 extend
outwardly and are molded integral with the vertical sides of the
rear frame ring 56. As seen in FIG. 12, the inside faces of the
column halves 60 and 61 and the support arms 45 have an appropriate
pattern of ribbing 64 to selectively rigidify the support structure
43 while still permitting flexure thereof.
[0072] In the column base 59, this column base 59 terminates at a
bottom wall 65 (FIGS. 9, 10 and 12), which is formed with a bore 66
extending vertically therethrough. The bottom wall 65 further is
formed integral with the bayonet connector 49 wherein the bore 66
extends vertically through this bottom wall 65 and the bayonet 49
as seen in FIG. 10. When joining the back frame 23 to the chair
uprights 20, the fastener 50 extends upwardly from the uprights 20
as will be described in further detail herein and extends through
the fastener bore 66 so that it projects vertically above the
bottom column wall 65. The upper end of the fastener 50 is engaged
by the threaded nut 51 as seen in FIG. 10 to thereby secure the
back frame 23 to the uprights 20. This interconnection between
these components will be described in further detail
hereinafter.
[0073] Further as to the bottom wall 65, this wall extends
forwardly to define a horizontal leg 68 of the L-shaped flange 46,
which flange 46 then turns downwardly to define a vertical leg 69
(FIGS. 5, 7 and 10). The bottom column section 59 serves to rigidly
support the bottom cross rail 37 of the back frame 23. As such, the
bottom frame rail 37 is more rigidly supported and has less
relative movement under occupant loads than the middle frame areas
supported by the support arms 45 or even the upper frame corners 38
which have the greatest amount of displaceability. In this manner,
the rear frame unit 55 provides for controlled flexing of the
entire back frame 23.
[0074] Referring to FIGS. 11 and 12, the rear frame ring 56
comprises top and bottom ring sections 71 and 72 and left and right
ring sections 73 which extend vertically. As seen in FIG. 14, each
side ring section 73 includes raised connector ribs 74 and 75 as
well as an additional rib 76 which defines the inside end of the
spline channel 42 and is also located directly adjacent to a spline
groove 77 that is adapted to accommodate the thickness of the
spline 58. The outer edge of the ring side section 73 includes a
thinner portion 78 and essentially defines the rear side portion of
the spline channel 42.
[0075] As to the horizontal rail section 71, this rail section 71
includes an interior rib 80, a channel rib 81 and an intermediate
connector face 82. Adjacent to the channel rib 81, a spline groove
83 is provided to accommodate the thickness of the spline 58 while
the outer edge portion 73 continues across the top ring section
71.
[0076] Referring to FIGS. 16 and 20, the lower rail section 72
includes a spline channel 85 along its entire lateral width so as
to accommodate the spline 58. Here again, the outer edge portion 78
continues through this region to define the back portion of the
spline channel 42. In the middle of the lower ring section 72, a
recessed pocket 87 is defined which opens upwardly and is located
vertically adjacent to a locking post 88, the function of which
will be described in further detail hereinafter.
[0077] The pocket 87 is defined by side walls 89 which side walls
89 include notches 90 at the bottom end thereof directly adjacent
to the spline groove 85. It is noted that all of the spline grooves
77, 83 and 85 are arranged in end-to-end relation so as to define a
continuous groove for continuously accommodating the spline 58
therein. Further, the channel ribs disposed directly adjacent to
these spline grooves 77, 83 and 85 are formed continuously in
end-to-end relation.
[0078] Turning next to the front frame ring 57, this frame ring 57
has a front face 92 which faces forwardly and a rear face 93 which
faces rearwardly towards the rear frame ring 56 and is adapted to
abut thereagainst and be fixedly secured thereto. This frame ring
57 is defined by vertical ring sections 94 and a top ring section
95 and a bottom ring section 96.
[0079] As to the side ring sections 94 (FIG. 14), these ring
sections 94 include a rearwardly projecting connector rib 98 and an
interior edge portion 99 which are adapted to abut against and be
fixedly secured to the connector ribs 75 on the rear frame ring 56.
Preferably, the front and rear frame rings 57 and 56 respectively
are joined together by ultrasonic welding of these components with
the faces disposed in contact being welded together. The front ring
sections 94 are molded with a channel rib 99 disposed directly
adjacent to a spline groove 100, which spline groove 100 is
disposed in opposing relation with the other spline groove 77 to
define an enlarged interior portion in which the spline 58 may be
received. The outer edge portion 101 of the front ring 57 is
disposed adjacent to but spaced apart from the other edge portion
78 to thereby define the entry portion of the spline channel
42.
[0080] As to the top ring section 95 (FIG. 15), this is formed
similar in that it includes a channel rib 102 and a spline groove
103 which is disposed directly adjacent to the outer edge portion
101 to thereby form the spline channel 42 in cooperation with the
spline groove 83 and outer edge portion 78 of the rear frame ring
56. The outer edge portion 101 of the front frame ring 57
furthermore extends downwardly along the other vertical ring
section 93 and then across the bottom ring section 96.
[0081] The bottom ring section 96 (FIG. 16) is formed with a spline
groove 105 extending thereacross in alignment with the opposing
rear spline groove 85. In this manner, the rear frame ring 56
defines a rear portion of the spline groove 42 while the front
frame ring 57 defines a front portion thereof which said frame
rings 56 and 57 when disposed in opposing relation define the
channel 42 so that it opens radially outwardly and has an enlarged
interior groove in which the spline 58 and associated fabric
material may be received in non-removable engagement. As best seen
in FIG. 14, the fabric 25 is wrapped around the spline 58 to
essentially define a folded hem which folded hem is then pressed
into the spline channel 42 by an appropriate tool or tooling.
[0082] In this manner, the suspension fabric 25 is tightly fitted
onto the back frame 23 so that the fabric material 25 is stretched
taut as generally illustrated in FIG. 10 and then angles away from
the back frame 23 and spans the central frame opening 40.
[0083] The suspension fabric 25 is formed of any suitable
suspension material which preferably is elasto-meric and preferably
has an open weave that provides for breathability. FIG. 13
generally illustrates the formation of the pieces of suspension
fabric 25 wherein FIG. 13 illustrates an initial stock material 110
from which is cut multiple pieces of the suspension fabric 25. The
suspension fabric 25 preferably is formed as a single layer but may
have multiple overlying layers and may also include cushioning
included therein.
[0084] In the office chair 10 of the invention, the chair 10 may be
provided with a separate cushioned pad 111 (FIGS. 17 and 18) that
covers the suspension fabric 25. The pad 111 has an upper pocket
112 and a lower pocket 113 that are adapted to be pulled over and
fitted onto the back frame 23. The pad 111 is formed as a composite
pad having a rear fabric layer 114, an intermediate cushion 115 and
a front fabric layer 116 which layers 114, 115 and 116 are all sewn
together about their peripheral edges.
[0085] To define the upper pocket 112, upper and lower pocket walls
117 and 118 are provided which are formed of a flexible fabric
material and are sewn on three sides to the adjacent peripheral
edges of the composite pad 111. The pad 111 is installed by first
placing one of the pockets 112 or 113 over the associated
horizontal edge of the back frame 23 and then pulling the other
pocket vertically and fitting this on the opposite horizontal frame
edge.
[0086] More particularly as to the frame mounting pocket 87 formed
in the back frame ring 56, the front side of the pocket 87 is
enclosed by the front frame ring 57. This pocket 87 is provided to
support the lower end of a pelvic support unit or pusher 120 which
faces forwardly and is adapted to press against the rear pelvic
region of a chair occupant. Referring to FIGS. 21-23, the pelvic
support 120 has an enlarged panel or pad 121 that is supported on a
cantilevered support arm 122. The lower end of the support arm 122
has a plug portion 123 which is forked to define a pair of locking
legs 124. The distal ends of the legs 124 include nubs 125 that
project sidewardly or outwardly for engagement with the notches 90
formed in the pocket 87. Also the plug portion 123 includes a
locking recess 126 which opens rearwardly and essentially is
defined by a blind bore.
[0087] When the front and rear frame rings 56 and 57 are fixed
together such as by welding, the support pocket 87 still opens
upwardly from between the interface between these two ring
sections. This permits the plug portion 123 of the pelvic support
120 to be plugged downwardly into the pocket 87. During this
downward insertion, the connector legs 124 deflect inwardly toward
each other until the nubs 125 align with the corresponding pocket
notches and then return to their undeflected condition with the
nubs 125 seated in the notches 90.
[0088] Since the pelvic support 120 is formed of a resiliently
deflectable material such as plastic, the support arm 122 is able
to be bent forwardly during insertion or even for removal to permit
the pocket post 88 to slide along the face of the pelvic support
120 until it aligns with the corresponding locking recess 126,
after which the support arm 122 returns to its undeflected
condition with the post 88 seated within the recess 126. These
cooperating components prevent unintentional vertical displacement
of the pelvic support 120. Since the resiliently deflectable
suspension fabric 25 lies against the front face 127 of the support
panel 121, the fabric 25 tends to press the pelvic support 120
rearwardly so that the stop post 88 is most effective in preventing
removal of the pelvic post 120. However, since the suspension
fabric 25 also is stretchable, the pelvic support 120 may still be
bent forwardly to permit removal of same from the support pocket
87.
[0089] Turning to the connection of the back assembly 24 to the
tilt control mechanism 19, this is accomplished through the bayonet
connector 49 referenced above. The tilt control mechanism 19 has
two separate uprights 20 which project rearwardly from opposite
sides of the chair and have their upper ends aligned in side by
side relation to define the aforementioned connector hub 22. The
above-described central column of the back assembly 24 fits into
this hub 22 and rigidly holds the uprights 20 in aligned side by
side relation through use of the aforementioned bolt 50.
[0090] Referring to FIGS. 25-28, the bayonet connector 49 projects
downwardly from a lower surface 130 of the column base 59. As seen
in FIG. 25, the downwardly projecting bayonet connector 49 has the
fastener bore 66 extending through the vertical length thereof. The
lateral sides 131 of the bayonet connector 49 have a shallow taper
wherein the sides 131 converge inwardly downwardly. In the middle
of the bayonet back face 132, a vertically elongate slot 133 is
provided along the entire length of the bayonet connector 49. This
slot 133 has a bottom opening 134 and convergent slot edges 135
which taper inwardly upwardly.
[0091] Referring to FIG. 26, the bayonet front face 136 also is
tapered relative to the back face 132 although the taper of the
back face 132 is shallower than the taper of the front face 136.
Hence, the bayonet 49 is tapered in both the front to back plane
and the side to side plane. The lowermost corners of this front
face 136 are provided with reliefs or cutouts 137.
[0092] FIGS. 27 and 28 are cross-sectional views as taken through
the bayonet connector 49. As can be seen, the central bore 66
extends vertically therethrough. The front face 136 faces forwardly
and has facets that curve generally sidewardly until terminating in
the reliefs 137 in the bottom area thereof.
[0093] In the center portion of the front face 136, a front groove
138 is provided between a pair of protuberances 139. When comparing
FIGS. 27 and 28, the groove 138 is deeper near the top of the
bayonet connector 49 as seen in FIG. 27 and is shallower at the
lower end (FIG. 28). The protuberances 139 also decrease in height
when comparing the top end (FIG. 27) and the lower end (FIG.
28).
[0094] As to the slot 133, this slot 133 is shallower at the lower
end (FIG. 28) as compared to the upper end (FIG. 27). This slot 133
as well as the groove 138 tend to draw the upper ends of the
uprights 20 sidewardly together and hold these ends in side by side
relation. At the same time, the tapered side faces 131 and the
tapered front and back faces 132 and 136 facilitate a snug fit when
these components are drawn together by the bolt 50.
[0095] More particularly as to the upright 20, FIGS. 29 and 30
illustrate a left side upright 20. The opposite right side upright
20 is formed substantially as a mirror image relative to the
upright of FIGS. 29 and 30 and hence, a detailed discussion thereof
is not required.
[0096] More particularly, the front end of the upright 20 includes
a hexagonal hole 141 which fits onto the end of a pivot shaft
disposed within the tilt control housing 19. The opposite upright
20 also mounts onto the opposite end of this pivot shaft so that
both of the uprights 20 pivot downwardly in unison during rotation
of the shaft.
[0097] The intermediate section of each upright 20 includes a seat
mount 142 on which the back end of the seat assembly 30 is
supported.
[0098] Most importantly, at the back end of the upright 20, a hub
section 143 is provided which defines one-half of the hub 22
mentioned above. The hub section 143 includes a chamber 144 that
has an open upper end 145 and an open inner side 146. On the left
side upright 20 illustrated in FIGS. 29 and 30, a locator knob 145
projects sidewardly from the inside face 146 of the hub section
143. With respect to the right side upright 20, this locator knob
145 is instead replaced with a shallow locator bore in which the
knob 145 is received in tight-fitting engagement. The illustration
of the inside face of this right side upright 20 is identical to
FIG. 29 except it is a mirror image thereof wherein the illustrated
knob 145 of FIG. 29 would in fact be a circular recess.
[0099] Referring to FIGS. 31 and 32, the shape of the socket
section 144 has an interior profile as illustrated in FIGS. 31 and
32 which is substantially a negative image of the exterior profile
of the bayonet connector 49 illustrated in FIGS. 27 and 28.
[0100] More particularly, the socket section 144 has a bottom wall
150 that has one-half of a bore 151 formed therein adjacent to the
inside hub face 147. When two hub sections 143 are joined side by
side, the bore sections 151 align sidewardly adjacent to each other
to define a circular bore through which the bolt 50 passes. These
bore sections 151 open downwardly adjacent to a bottom wall face
152 against which the head 153 of the bolt 50 abuts as illustrated
in FIG. 19.
[0101] The socket sections 144 also each include a socket side face
155 which tapers upwardly outwardly, and a back face 156 which also
tapers upwardly outwardly. The front socket face 157 has a curved
profile and tapers upwardly outwardly with a more pronounced taper
as compared to the back face 156. This front face then curves to
define a projection 158 that is progressively thicker in the upward
direction as seen in FIGS. 32 and 31. Further, the back face 156
terminates at a central rib section 160.
[0102] Referring to FIG. 33, when the two hub sections 143 are
joined side by side to each other the two socket sections 144 are
aligned sidewardly in registry to define an upward opening socket
162 of the hub 22, and the rib sections 160 essentially define a
vertically elongate rib 161. This rib 161 slidably fits within the
corresponding slot 133 of the bayonet connector 49. Since the slot
133 is tapered, this draws the rib sections 160 sidewardly together
and prevents any sideward displacement of the hub sections 143 away
from each other once the back assembly 24 is installed within the
hub 22. Similarly, the projections 158 define a shallow rib 164
which fit into the groove 138 to further assist in drawing these
hub sections 143 sidewardly together.
[0103] The tapered shape of the bayonet connector 49 and the
corresponding socket 162 provides for a snug fit between the
opposing faces of these components. It will be understood that FIG.
33 includes some clearance space between these spaces for
diagrammatic purposes to assist in the illustration thereof but
that the spacing between such surfaces is much closer in practice
to prevent any undesirable looseness in the back assembly 24.
Referring to FIG. 19, the hub 22 is generally depicted by the
bottom wall 150 thereof. During assembly, the bayonet connector 49
is fitted into the socket 162 of the hub 22 and then these
components are drawn tightly together by insertion of the bolt 50
through the bore 66 and then the nut 51 is threaded thereon to
place these components in compression. A Bellville washer 165 or
other resilient or mechanical locking means may be provided to
prevent any loosening of the bolt 50 and nut 51.
[0104] As an additional feature of this connector arrangement, this
arrangement also may be used to secure the lumbar assembly 28 in
place. Referring to FIG. 10, this lumbar assembly 28 may include an
upright support bracket 170 having a bottom bracket wall 171. As
seen in FIG. 19, this bottom bracket wall 171 includes a rearward
opening slot 172 to permit the bracket 170 to be slid around or
straddle the bolt 50 wherein the nut 51 then presses directly
downwardly on this bracket wall 171 to secure the lumbar assembly
128 in place. Alternatively, as generally depicted in FIG. 7, this
lumbar assembly 28 also need not be provided wherein the nut 51
would be positioned directly onto the upper face of the column wall
65.
[0105] Hence, the bayonet connection 49 not only serves to join the
bayonet connector 49 to the hub 22, but also serves as the
connector arrangement for the lumbar assembly 28 which optionally
may be installed on this chair 10.
[0106] With respect to the above-described chair 10, the back frame
24 is assembled by first joining the rear frame ring 56 to the
front frame ring 57 by ultrasonic welding. Thereafter, the
suspension fabric 25 is resiliently stretched over the back frame
23 with the peripheral edges of the fabric 25 being affixed into
the spline groove 42 by the spline 58. If desired, the pelvic
support 120 may be plugged into the appropriate pocket 87 formed in
the bottom frame rail 37.
[0107] Thereafter, to mount the back assembly 24 to the tilt
control mechanism 19, the frame bayonet connector 49 is plugged
into the socket 162 of the hub 22. The appropriate fastener 50 with
its associated Bellville washer 165 are inserted upwardly through
the fastener bore 60 and then nut 51 is threaded on the upper end
of the bolt 50. If the lumbar assembly 28 is being provided, this
would then be positioned by sliding its bracket 170 onto the bolt
50 after which the nut 51 would then be tightened to secure all of
these components together. In this manner, the back assembly 24 is
rigidly connected to the uprights 20 and tilts rearwardly
therewith.
[0108] As an alternative to the above described frame construction,
FIGS. 34 and 35 illustrate a multi-component back frame 180 which
comprises a rear frame unit 181 and a front frame ring 182. The
rear frame unit 181 and front frame ring 182 are substantially
similar to the components described above and thus a detailed
discussion of these components is not believed to be required with
the following discussion primarily relating to additional
modifications to this frame construction.
[0109] In this regard, these frame components 181 and 182 would
include appropriate fastener bores 183 such that the rear frame
unit 181 and front frame ring 182 could be fastened together by
screws 184. Once these two frame sections 181 and 182 are joined
together, they essentially define a spline groove 185 in a manner
substantially similar to that described above. Thereafter, the back
frame 180 also includes an elastomeric pad ring 190 which generally
conforms to the shape of the front frame ring 182 but is formed of
a compressible material such as a spongy foam. FIG. 35 illustrates
in phantom outline the initial cross-sectional profile of this pad
ring 190 when secured to the front frame ring 182.
[0110] The back frame 180 also includes a suspension fabric 191
that has a spline 192 sewn to its periphery by threads 193 or other
suitable fastening means. This spline 192 fits into the spline
channel 185 to secure the suspension fabric 191 in place.
[0111] The suspension fabric 191 preferably is an elastomeric
material which is tensioned when installed. To facilitate
tensioning of this suspension fabric 191, the pad ring 190
preferably is compressed as illustrated in solid outline in FIG. 35
wherein the compression of the pad 190 adds an additional outward
biasing force to the suspension fabric 191 to increase the tension
therein. As an additional function, the pad ring 190 also overlies
the screws 184 and hides these components from view.
[0112] Referring to FIG. 35 as well as additional FIGS. 36-39, the
spline 192 also has an improved inventive construction. More
particularly, the suspension fabric 191 comprises an initial
pattern of sheet material 195 formed of an elastomeric fabric cut
to an appropriate shape as seen in FIG. 36. The spline itself
comprises two U-shaped spline sections 196 and 197. Initially as
seen in FIGS. 38 and 39, these spline sections 196 and 197 are
formed in a straight configuration with V-shaped cut-outs provided
therein. In particular, these V-shaped cut-outs facilitate bending
of the spline sections 196 and 197.
[0113] Referring to FIG. 35, it is noted that the spline section
has a relatively wide cross-sectional shape defined by a bulbous
end portion 200 and an interior edge 201. One side of the spline
section 196 includes slide ribs 202 while the opposite side
includes a locking rib 203 thereon. This locking rib 203 projects
outwardly and inwardly into the groove to tightly squeeze the
material of the suspension fabric against the interior side wall of
the spline groove 185.
[0114] Because of this wide shape, it is necessary to provide the
patterns of cut-outs to facilitate bending of this wide plastic
spline piece. More particularly, each of the spline sections 196
and 197 as illustrated in FIGS. 38 and 39 include first and second
groups of V-shaped cut-outs 205, 206, 207 and 208 which correspond
to the corners of the back frame, as well as additional individual
cut-outs 209. The patterns of cut-outs at the corners 205, 206, 207
and 208 provide for a significant amount of bending while the
additional individual cut-outs 209 are only needed to provide
gentle curvature.
[0115] As seen in FIGS. 36 and 37 the splines 196 and 197 initially
have the cut-outs facing outwardly after which the spline sections
196 and 197 are sewn directly onto the fabric material 195 by the
threads 193. These threads 193 pierce directly through the fabric
material as well as the plastic of the spline sections 196 and
197.
[0116] To effect insertion of the spline 192 into the spline groove
185, the spline sections 196 and 197 are then flipped or folded
inwardly wherein the edge 201 initially starts at the outside of
the fabric 195 as seen in FIG. 36 and then is folded inwardly so
that it is seated within the inner end of the spline groove 185.
The various cut-outs therefore first serve to permit bending to the
shape illustrated in FIGS. 36 and 37 wherein the cut-outs are
located along the outer edge and then are flipped inwardly and
permits a reverse bend in the spline sections 196 and 197 with the
cut-outs now being located on the inside end of the spline groove
185. In this manner, the spline 192 is installed by folding the
spline inwardly and inserting same into the peripheral spline
groove 185 formed in the back frame 180.
[0117] Although particular preferred embodiments of the invention
have been disclosed in detail for illustrative purposes, it will be
recognized that variations or modifications of the disclosed
apparatus, including the rearrangement of parts, lie within the
scope of the present invention.
* * * * *