U.S. patent application number 11/119632 was filed with the patent office on 2006-12-21 for chair with recline control mechanism, recline limit control and back tilt mechanism.
Invention is credited to Aaron Michael Ickes, John Koch, Marcus C. Koepke, Jay R. Machael.
Application Number | 20060284461 11/119632 |
Document ID | / |
Family ID | 37052547 |
Filed Date | 2006-12-21 |
United States Patent
Application |
20060284461 |
Kind Code |
A1 |
Machael; Jay R. ; et
al. |
December 21, 2006 |
Chair with recline control mechanism, recline limit control and
back tilt mechanism
Abstract
A chair having a recline control mechanism, a limit control
apparatus and a tilt mechanism. The recline control mechanism
operates to adjust resistance to rotation of a back assembly of the
chair and includes an actuator lever having a lock structure
attached to a movable spring assembly. Moving the spring assembly
toward and away from a rotation axis for the back assembly adjusts
the resistance. The limit control apparatus selectively limits the
extent of rotation of the back assembly from about zero degrees to
about 3.5 degrees to about seven degrees by using abutment
surfaces. The tilt mechanism provides an independent and stable yet
passive tilt capability to a backrest of the back assembly by using
a pair of brackets, two pairs of links and two pairs of rods.
Inventors: |
Machael; Jay R.; (Muscatine,
IA) ; Koepke; Marcus C.; (Indianapolis, IN) ;
Koch; John; (Iowa City, IA) ; Ickes; Aaron
Michael; (Davenport, IA) |
Correspondence
Address: |
FAEGRE & BENSON, LLP;ATTN: PATENT DOCKETING
90 SOUTH SEVENTH STREET
2200 WELLS FARGO CENTER
MINNEAPOLIS
MN
55402
US
|
Family ID: |
37052547 |
Appl. No.: |
11/119632 |
Filed: |
May 2, 2005 |
Current U.S.
Class: |
297/300.1 |
Current CPC
Class: |
A47C 1/026 20130101;
A47C 7/443 20130101 |
Class at
Publication: |
297/300.1 |
International
Class: |
A47C 1/024 20060101
A47C001/024 |
Claims
1. A chair with a reclining back comprising: a seat assembly; a
back assembly including a frame member connected to said seat
assembly; a pivot forming structure defining an axis of rotation
for allowing said back assembly to rotate relative to said seat
assembly; and a biasing structure for resisting the rotation of
said back assembly, said biasing structure being spaced from said
axis of rotation of said back assembly and being movable forwardly
toward said axis of rotation and rearwardly away from said axis of
rotation for controlling resistance to rotation of said back
assembly.
2. The chair of claim 1 including: an actuator structure connected
to said biasing structure for moving said biasing structure.
3. The chair of claim 1 including: a lock structure connected to
said biasing structure for locking said biasing structure in a
selected position.
4. The chair of claim 1 including: a lock structure connected to
said biasing structure for locking said biasing structure in a
selected position; and an actuator structure connected to said
biasing structure and to said lock structure for selectively
locking and unlocking said lock structure and for moving said
biasing structure.
5. The chair of claim 1 wherein: said pivot forming structure
includes a lower mount and an upper mount.
6. The chair of claim 1 wherein: said biasing structure includes a
spring.
7. The chair of claim 1 including: a lock structure connected to
said biasing structure for locking said biasing structure in a
selected position; and an actuator structure connected to said
biasing structure and to said lock structure for selectively
locking and unlocking said lock structure and for moving said
biasing structure; and wherein said pivot forming structure
includes a lower mount and an upper mount.
8. The chair of claim 7 wherein: said biasing structure includes a
spring.
9. The chair of claim 1 including: a limit control apparatus
connected to said back assembly and to said pivot forming structure
for limiting recline of said back assembly.
10. The chair of claim 9 wherein: said limit control apparatus
includes a first structure having a stepped configuration with a
plurality of abutment surfaces, each of said abutment surfaces
being disposed in a generally horizontal attitude, said first
structure being connected to either a chair lower mount or to the
reclining back assembly; a second structure including an abutment
surface for selectively engaging said abutment surfaces of said
first structure, said abutment surface of said second structure
being disposed in a generally horizontal attitude; and an actuator
structure being connected either to said first structure or to said
second structure for controlling engagement of said first and said
second structures.
11. The chair of claim 10 wherein: said actuator structure is
rotatable about a generally vertical axis; and said second
structure slides linearly in response to movement of said actuator
structure.
12. The chair of claim 11 wherein: said second structure includes a
projection forming said abutment surface, a slidable base for
mounting said projection and a post connected to said base and to
said actuator structure.
13. The chair of claim 12 wherein: said second structure is mounted
to a chair lower mount and said first structure is mounted to said
back assembly.
14. The chair of claim 1 wherein: said back assembly includes a
tilt mechanism for maintaining said back assembly in contact with a
chair user during recline of said back assembly.
15. The chair of claim 14 wherein: said tilt mechanism includes a
first bracket affixed to a frame member that is part of said back
assembly, said first bracket having a first pair of holes and a
second pair of holes; a second bracket pivotally mounted to said
first bracket and affixed to a back of said back assembly, said
second bracket having a first pair of holes and a second pair of
holes; a first pair of links, each link of said first pair of links
having first and second end portions; a second pair of links, each
link of said second pair of links having first and second end
portions; a first structure for pivotally connecting said first
bracket through said first pair of holes and said first end
portions of said first pair of links; a second structure for
pivotally connecting said second bracket through said first pair of
holes and said second end portions of said first pair of links; a
third structure for pivotally connecting said first bracket through
said second pair of holes and said first end portions of said
second pair of links; and a fourth structure for pivotally
connecting said second bracket through said second pair of holes
and said second end portions of said second pair of links.
16. The chair of claim 15 wherein: said first structure includes a
first rod; said second structure includes a second rod; said third
structure include a third rod; and said fourth structure includes a
fourth rod.
17. The chair of claim 16 wherein: said first rod is mounted in
said first pair of holes of said first bracket and in holes of said
first end portions of said first pair of links; said second rod is
mounted to holes in said second end portions of said first pair of
links and in said first pair of holes of said second bracket; said
third rod is mounted in said second pair of holes of said first
bracket and to holes in said first end portions of said second pair
of links; and said fourth rod is mounted to holes in said second
end portions of said second pair of links and in said second pair
of holes of said second bracket.
18. The chair of claim 9 including: a tilt mechanism for
maintaining said back assembly in contact with a chair user during
recline of said back assembly.
19. The chair of claim 18 wherein: said tilt mechanism includes a
first bracket affixed to a frame member that is part of said chair
back assembly, said first bracket having a first pair of holes and
a second pair of holes; a second bracket pivotally mounted to said
first bracket and affixed to a back of said back assembly, said
second bracket having a first pair of holes and a second pair of
holes; a first pair of links, each link of said first pair of links
having first and second end portions; a second pair of links, each
link of said second pair of links having first and second end
portions; a first structure for pivotally connecting said first
bracket through said first pair of holes and said first end
portions of said first pair of links; a second structure for
pivotally connecting said second bracket through said first pair of
holes and said second end portions of said first pair of links; a
third structure for pivotally connecting said first bracket through
said second pair of holes and said first end portions of said
second pair of links; and a fourth structure for pivotally
connecting said second bracket through said second pair of holes
and said second end portions of said second pair of links.
20. The chair of claim 19 wherein: said first structure includes a
first rod; said second structure includes a second rod; said third
structure include a third rod; and said fourth structure includes a
fourth rod.
21. A limit control apparatus for a reclining back assembly of a
chair comprising: a first structure having a stepped configuration
with a plurality of abutment surfaces, each of said abutment
surfaces being disposed in a generally horizontal attitude, said
first structure being connected to either a chair lower mount or to
the reclining back assembly; a second structure including an
abutment surface for selectively engaging said abutment surfaces of
said first structure, said abutment surface of said second
structure being disposed in a generally horizontal attitude; and an
actuator structure being connected either to said first structure
or to said second structure for controlling engagement of said
first and said second structures.
22. The apparatus of claim 21 wherein: said actuator structure is
rotatable about a generally vertical axis; and said second
structure slides linearly in response to movement of said actuator
structure.
23. The apparatus of claim 22 wherein: said actuator structure
includes a handle and a link, said link having a first end portion
pivotally connected to said handle and a second end portion having
a slot for pivotal engagement with said second structure.
24. The apparatus of claim 23 wherein: said second structure is
mounted to a chair lower mount and said first structure is mounted
to the back assembly.
25. The apparatus of claim 21 wherein: said second structure
includes a projection forming said abutment surface, a slidable
base for mounting said projection and a post connected to said base
and to said actuator structure.
26. The apparatus of claim 21 wherein: said actuator structure is
rotatable about a generally vertical axis; said second structure
slides linearly in response to movement of said actuator structure;
and said second structure includes a projection forming said
abutment surface, a base for mounting said projection and a post
connected to said base and to said actuator structure.
27. The apparatus of claim 26 wherein: said second structure is
connected to a lower mount and said first structure is mounted to
the back assembly.
28. A tilt mechanism for a chair back comprising: a first bracket
adapted to be affixed to a chair frame member that supports the
chair back, said first bracket having a first pair of holes and a
second pair of holes; a second bracket pivotally movably mounted to
said first bracket adapted to be affixed to the chair back, said
second bracket having a first pair of holes and a second pair of
holes; a first pair of links, each link of said first pair of links
having first and second end portions; a second pair of links, each
link of said second pair of links having first and second end
portions; a first structure for pivotally connecting said first
bracket through said first pair of holes and said first end
portions of first pair of links; a second structure for pivotally
connecting said second bracket through said first pair of holes and
said second end portions of said first pair of links; a third
structure for pivotally connecting said first bracket through said
second pair of holes and said first end portion of said second pair
of links; and a fourth structure for pivotally connecting said
second bracket through said second pair of holes and said second
end portions of said second pair of links.
29. The tilt mechanism of claim 28 wherein: said first structure
includes a first rod; said second structure includes a second rod;
said third structure includes a third rod; and said fourth
structure includes a fourth rod.
30. The tilt mechanism of claim 29 wherein: said second bracket is
restricted to move in a two-dimensional plane generally
perpendicular to longitudinal axes of said first, said second, said
third and said fourth rods.
Description
BACKGROUND OF THE INVENTION
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not applicable.
[0003] 1. Field of the Invention
[0004] The present invention relates to a chair with a reclining
back assembly and, more particularly, to a chair that includes a
more efficient mechanism for adjusting resistance to the recline of
a chair back assembly, a simple apparatus for limiting the angle of
recline and a tilt mechanism that results in a more comfortable
passive tilt adjustment of a chair back in various chair recline
positions.
[0005] 2. Description of the Related Art
[0006] Reclinable office chairs are ubiquitous and appear in many
different styles and designs and with many different functions.
Most, if not all, include some mechanism to resist a reclining
back. See for example, U.S. Pat. No. 6,053,574 which includes
movable springs. Some chairs also include adjustable stops to
control the angle of recline. See for example, U.S. Pat. Nos.
6,616,231 and 6,193,314. Still other chairs include tiltable backs.
See for example, U.S. Pat. Nos. 1,756,825 and 3,938,858 and Reissue
36,335. Adjustable office chairs are sometimes complicated to
operate or are overly complex in structure and are often expensive,
unreliable or difficult to use.
BRIEF SUMMARY OF THE INVENTION
[0007] The difficulties encountered with previous devices have been
over come by the present invention. What is described here is a
chair with a reclining back including a seat assembly, a back
assembly, a pivot forming structure defining an axis of rotation
for allowing the back assembly to rotate relative to the seat
assembly and a biasing structure for resisting the rotation of the
back assembly, the biasing structure being spaced from the axis of
rotation and also being movable forwardly and rearwardly relative
to the axis of rotation with specific structural elements as a way
of controlling resistance to the rotation of the back assembly. The
invention here also includes a limit control apparatus having
specific structure including a first structure having a step
configuration, a second structure including an abutment surface for
engaging the first structure and an actuator for moving either the
first or second structures. The present invention further includes
a tilt mechanism for the back of the back assembly including a
first bracket, a second bracket, a first pair of links, a second
pair of links, a first rod and a second rod so as to allow the
second bracket which is connected to the chair back to pivot in a
plane generally perpendicularly to the axes of the rods so as to
provide a stable but passive adjustment of the chair back as the
back assembly reclines.
[0008] A complete understanding of the present invention and other
objects, advantages and features thereof will be gained from a
consideration of the present specification which provides a written
description of the invention, and of the manner and process of
making and using the invention, set forth in such full, clear,
concise, and exact terms as to enable any person skilled in the art
to which it pertains, or with which it is most nearly connected, to
make and use the same in compliance with Title 35 U.S.C. section
112 (first paragraph). Furthermore, the following description of a
preferred embodiment of the invention read in conjunction with the
accompanying drawing provided herein represent an example of the
invention in compliance with Title 35 U.S.C. section 112 (first
paragraph), but the invention itself is defined in the Claims
section attached hereto.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0009] FIG. 1 is a rear isometric view of the inventive office
chair described herein.
[0010] FIG. 2 is a sectional elevation view of the chair shown in
FIG. 1 in an upright position.
[0011] FIG. 3 is a sectional elevation view similar to that shown
in FIG. 2 but with the chair in a fully reclined position.
[0012] FIG. 4 is a front isometric view of controls and frame
members of the chair shown in FIG. 1.
[0013] FIG. 5 is an enlarged top plan view of a box for the
controls of the chair shown in FIG. 1.
[0014] FIG. 6 is an isometric view of the box shown in FIG. 5 and
including a bracket for attachment of the box to a support
column.
[0015] FIG. 7 is an isometric view of an upper mount of the chair
shown in FIG. 1.
[0016] FIG. 8 is an exploded isometric of the elements shown in
FIG. 4 but with the absence of some elements.
[0017] FIG. 9 is an isometric view of a plastic slide plate.
[0018] FIG. 10 is an isometric view of the controls of the chair of
FIG. 1 showing a spring assembly absent a helical spring and a top
cap.
[0019] FIG. 11 is an isometric view of an actuator lever for
vertical adjustment of the chair shown in FIG. 1.
[0020] FIG. 12 is an isometric view of the top cap for the spring
assembly of the chair shown in FIG. 1.
[0021] FIG. 13 is an isometric view of the helical spring used in
the spring assembly.
[0022] FIG. 14 is a downward looking isometric view of a spring
guide for the spring assembly.
[0023] FIG. 15 is an upward looking isometric view of the spring
guide shown in FIG. 14.
[0024] FIG. 16 is an isometric view of a spring carrier of the
spring assembly.
[0025] FIG. 17 is an isometric view of a recline control mechanism
for moving the spring assembly.
[0026] FIG. 18 is an isometric view of an actuator lever of the
recline control mechanism.
[0027] FIG. 19 is a downward looking isometric view of a crank of
the recline control mechanism.
[0028] FIG. 20 is a bottom view of the crank shown in FIG. 19.
[0029] FIG. 21 is a partial sectional view illustrating a lock
structure in a locked position.
[0030] FIG. 22 is a view similar to FIG. 21 illustrating the lock
structure being unlocked.
[0031] FIG. 23 is a view similar to FIGS. 21 and 22 illustrating
the lock structure in an unlocked position.
[0032] FIG. 24 is a view similar to FIGS. 21-23 illustrating the
lock structure in an unlocked and moving position.
[0033] FIG. 25 is an isometric view of the recline control
mechanism and the spring assembly in a position close to a recline
rotation axis.
[0034] FIG. 26 is a view similar to FIG. 25 with the recline
control mechanism and the spring assembly in a position further
from the rotation axis than is shown in FIG. 25.
[0035] FIG. 27 is a view similar to FIGS. 25 and 26 illustrating
the recline control mechanism and the spring assembly in a position
furthest from the rotation axis.
[0036] FIG. 28 is a rear isometric view of the controls shown in
FIGS. 4 and 8 and illustrating a limit control apparatus.
[0037] FIG. 29 is an isometric view of a brace of the limit control
apparatus.
[0038] FIG. 30 is an isometric view of an actuator lever of the
limit control apparatus.
[0039] FIG. 31 is an isometric view of an abutment structure of the
limit control apparatus.
[0040] FIG. 32 is an isometric view of a slide block of the limit
control apparatus.
[0041] FIG. 33 is a diagrammatic elevation view of the actuator
lever, the abutment structure, and the slide block of the limit
control apparatus.
[0042] FIG. 34 is an exploded isometric view of a tilt mechanism
for the chair shown in FIG. 1.
[0043] FIG. 35 is an isometric view of the tilt mechanism in an
assembled condition.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0044] While the present invention is open to various modifications
and alternative constructions, the preferred embodiment
illustrating the best mode contemplated by the inventors of
carrying out their invention is shown in the various figures of the
drawing and will be described herein in detail, pursuant to Title
35 U.S.C. section 112 (first paragraph). It is understood, however,
that there is no intention to limit the invention to the particular
embodiment, form or example which is disclosed herein. To the
contrary, the intention is to cover all modifications, equivalent
structures and methods, and alternative constructions falling
within the spirit and scope of the invention as expressed in the
appended Claims section attached hereto, pursuant to Title 35
U.S.C. section 112 (second paragraph).
[0045] Referring now to FIGS. 1-3, there is illustrated a chair 10
having a back assembly 12, a seat assembly 14, a set of controls
16, a pair of arms 18, 20, a support column 22, a base 24, and a
set of casters 26, 28, 30, 32, 34.
[0046] The illustrated chair 10 is of an office type which swivels,
adjusts vertically, glides easily on a floor or carpet pad and
includes reclining and tilt back features. The reclining and tilt
back features are shown by comparing FIGS. 2 and 3 where in FIG. 2
the chair 10 is illustrated in a full upright position and in FIG.
3 the chair 10 is illustrated in a full recline position. The back
assembly 12 goes from an angle of about 86 degrees from a reference
vertical line 36 at full upright to about 79 degrees at full
recline, although other angles may be used. The backrest 38 of the
back assembly also reclines in a movement from about 10 degrees to
about 24 degrees. It is noted that the backrest 38 is independently
able to tilt a maximum of about 7.2 degrees while undergoing a
recline with the back assembly, although other angles may be
employed. It is further noted that the reclining and the tilt back
features may also be used on non-office chairs, for example, chairs
used in conference centers, theaters or lecture halls where there
may be no horizontal movement because the chairs are fixed to a
floor or a platform. The reclining and tilt back features may also
be used independently of each other. For example, a chair may have
the reclining feature but not the tilt back and vice versa.
[0047] The backrest 38 may include a support panel 42 and a back
cushion 44, the frame 40 may include a pair of parallel tubular
frame members 46, 48, and the back assembly 12 may include a tilt
mechanism 50 connecting the support panel 42 and the frame members
46, 48. The seat assembly 14 may include a seat pan 52 and a seat
cushion 54. It is noted that the back assembly may include only a
panel of flexible and/or resilient material such that a cushion is
not needed. The same may be true of the seat assembly where only a
seat panel of flexible and/or resilient material is used.
[0048] The base 24 may include five arms 60, 62, 64, 66, 68 and a
hub 70, and the base rigidly supports the column 22 in the hub 70.
The support column may include a gas cylinder for allowing vertical
adjustment of the seat and back assemblies.
[0049] The set of controls 16 are located in and about a lower
mount box 74, FIGS. 4, 5 and 6. The box 74 may include a pair of
side walls 76, 78 having lever openings 80, 82, 84, a front wall
86, a rear wall 88 and a bottom wall 90. The box may also include a
pair of horizontally extending flanges 92, 94 with fastener
receiving openings 96, 98, 100, 102 for fasteners (not shown) to
connect the box 74 to the seat pan 52. The bottom wall 90 may
include a series of lock holes 103 extending over an arc of about
30 degrees measured from a fastener receiving hole 104 located near
the lever opening 80. Another fastener receiving hole 106 may be
placed near the lever opening 84. A longitudinally directed slot
108 is formed in the center portion of the bottom wall 90 and a
column receiving opening 110 is formed toward the rear of the
bottom wall. Rigidly affixed to the bottom wall is a bracket 112 to
which the support column 22 may be connected. The side walls 76, 78
also include two horizontally aligned pivot openings 120, 122.
[0050] Pivotally mounted to the box 74 may be a U-shaped upper
mount plate 126, FIGS. 4 and 7. The upper mount plate 126 includes
a top wall 128, two side walls 130, 132 and a rear wall 133, FIG.
8. The top wall includes a longitudinally directed slot 134 and the
side walls include two horizontally aligned pivot openings 136,
138. As shown in FIGS. 4 and 8, the pair of frame members 46, 48
are attached to the plate 126 by any suitable technique such as by
welding. A pivot rod 140 may be inserted into the aligned openings
120, 122 of the box 74 and the aligned openings 136, 138 of the
plate 126. This arrangement, a pivot forming structure, allows the
back assembly 12 to recline relative to the remainder of the chair,
and in particular, relative to the seat assembly 14, the support
column 22 and the base 24 as is typical of an office chair.
[0051] The pivot forming structure of the control box 74, the plate
126 and the pivot rod 140 creates an axis of rotation 142, FIGS. 2
and 3, that is coincident with the longitudinal axis of the pivot
rod 140. This pivot axis is located forward of the support column
22. As seen in FIGS. 2 and 3, the axis of rotation 142 is under the
forward portion of the seat assembly 14. In one embodiment the
rotation axis 142 is about 6.125 inches forward of a vertically
aligned longitudinal axis 144, FIGS. 2 and 3 of the column 22.
[0052] Located within the box 74 may be a low friction plastic
slide plate 150, FIGS. 8 and 9, a slidable spring assembly 152,
FIGS. 2, 3, 8 and 10, a recline control mechanism 154, FIGS. 8 and
10, for moving the spring assembly forward toward the rotation axis
142 and rearward away from the rotation axis. The slide plate 150
includes a longitudinal slot 160 extending forwardly and rearwardly
which is parallel to and aligned with the slot 108 of the box 74
and the slot 134 of the plate 126. The slide plate 150 may also
include an opening 165 to receive the bracket 112, a first fastener
pass-through hole 164 that aligns with the hole 104 of the box 74,
a second fastener pass-through hole 166 that aligns with the hole
106 of the box 74, a series of detent recesses 168, two upstanding
flanges 170, 172, a lateral slot 174 along the rear portion of the
slide plate and a cut-out 176 to expose the lock holes 103. It
should be noted that the lock holes may be formed in the slide
plate and thus the cut-out may be obviated.
[0053] Extending from lever opening 82, FIG. 5, of the box 74 may
be an actuator lever 180, FIGS. 4, 8 and 10, for adjusting the
vertical height of the seat and back assemblies. Extending from the
lever opening 80 is an actuator lever 182, part of the recline
control mechanism 154 for controlling resistance to rotational
movement of the back assembly during recline, and extending from
the lever opening 84 is an actuator lever 184 for limiting the
degree of rotation of the back assembly.
[0054] The actuator lever 180 may include a handle portion 190,
FIG. 11, a fulcrum portion 192 and a bearing portion 194. The
fulcrum portion includes a hole 196 for receiving a pin 197, FIG.
18, that pivotally mounts the actuator lever 180 to the flanges
170, 172 of the slide plate 150. The bearing portion 194 operates
the air cylinder in the usual fashion known by those skilled in the
art.
[0055] The spring assembly 152 is a biasing structure and may
include a spring carrier 200, FIGS. 8, 10 and 16, having a tab
portion 202 with a pin receiving opening 204 and a slot 205, a
spring guide 206, FIGS. 8, 10, 14 and 15 with a post portion 208, a
cup portion 210 and a runner portion 212, a top cap 214, FIGS. 8
and 12, with a central opening 216, and a helical spring 218, FIG.
13. The helical spring 218 is mounted around the post portion 208
and is supported by the cup 210. The post portion 208 extends
through the central opening 216 of the top cap 214. The runner
portion 212 of the spring guide 206 extends through the slot 205 of
the spring carrier 200. The runner portion 212 extends into the
longitudinal slot 160 of the slide plate 150 and is guided and
limited by the slot 160. The upper end of the post portion 208
extends out of the central opening 216 of the top cap 214 and into
the slot 134 of the plate 126. The spring may be made of flattened
steel wire, 3 inches in length with a spring constant of 375 pounds
per inch of deflection. It is to be noted that other types of
energy devices may be used instead of the helical spring, such as a
rubber spring or an air spring.
[0056] The recline control mechanism 154 has a "lost motion"
feature and may include the actuator of lever 182 having a handle
portion 220, FIGS. 17-20 attached to a link portion 222. Also
included is a crank 224 mounted above the actuator lever 182. The
link portion 222 has a crank pin 226, a spring pin 228, two lock
ball openings 230, 232, a bridge wall 234 between the lock ball
openings, a tab cutout 236 and a fastener opening 238.
[0057] The crank 224 may include a fastener receiving opening 240,
FIGS. 19 and 20 to allow the crank to pivot independently of the
handle portion 220 and the link portion 222. The crank also
includes a tab recess 242 with a fastener receiving opening 244, a
crank pin slot 246, a U-shaped groove 248 and a ball cage flange
250 with a ball receiving slot 252. The recline control mechanism
154 also includes a lock ball 254 and a wire spring 256, FIGS. 8,
10 and 17. The lock ball 254, the ball cage flange 250, the bridge
wall 234 and the openings 230, 232 form a lock structure. The wire
spring 256 fits into the groove 248 and includes two legs 257, 258,
FIG. 8, that are pre-loaded to engage the spring pin 228 so that
movement of the spring pin 228 flexes one or the other of the legs
257, 258 to create a return biasing force acting on the crank 224
and thereby the lock ball 254. A shoulder bolt 259, FIG. 10,
extends through the openings 238, 240 in the link portion 222 and
the crank 224 pivotally connecting these elements to the box 74 by
threading into the hole 104. Another bolt 260, FIG. 10, extends
through the opening 204 in the carrier 206 and the opening 244 in
the tab recess 242 of the crank 224 to pivotally connect the
carrier 200 and the crank 224.
[0058] In operation, the actuator lever 182 is able to rotate a
short distance, about 3-4 degrees about the bolt 259 in a first
step so as to remove any restraint on the lock ball 254 exerted by
the bridge wall 234. As shown in sequence in FIGS. 21-24, the
bridge wall 234 depresses the lock ball 254 in one of the lock
holes 103 of the box 74 to lock the recline control mechanism 154
and the spring assembly 152. As the actuator lever 182 is rotated,
the bridge wall 234 moves away from the lock ball 254 so that the
lock ball is located under either the opening 230 or the opening
232. After the bridge wall 234 rotates out of the way, the lock
ball 254 is able to be moved from one of the lock holes 103 in the
bottom wall 90 of the box 74 to another lock hole. As rotation of
the actuator lever continues, the crank pin 226 of the link portion
222 engages one or the other ends 261, 262 of the wall surrounding
the crank slot 246. The crank 224 then moves causing the spring
assembly 152 to move along the slot 160 of the slide plate 150.
Motion is transmitted to the spring assembly 152 through the
carrier 200 which is connected to the crank 224 by the shoulder
bolt 260. The wire spring 256 ensures that after movement of the
spring assembly, the actuator lever 182 will be biased back to a
locking position where the bridge wall 234 again bears downwardly
on the lock ball 254 so as to drop it into one of the lock holes
103 in the bottom wall 90 of the box 74.
[0059] The purpose of the spring assembly 152 is to resist rotation
of the back assembly 12 about the rotation axis 142. The further
the spring assembly is from the rotation axis, the greater is the
moment arm and the higher is the resistance to the reclining back
assembly. By moving the spring assembly closer to the rotation
axis, the moment arm is decreased and recline of the back assembly
is more easily accomplished. This arrangement for altering the
tension applied to the back assembly is simple, robust, reliable
and very easy to use. The control may be accessed from the side of
the chair instead of from under the chair and operation merely
requires a lever to be pivoted with an attendant mechanical
advantage instead of a knob to be rotated. This feature also
provides a user easy feedback to easily judge the current tension
or resisting force and then to alter the force, if desired. Also,
moving the lever forward to decrease tension and rearward to
increase tension may be displayed graphically on the handle portion
220 which is easily seen by a chair user. This compares favorably
to an under chair knob without any indication of the correct
direction of rotation and with the great difficulty in determining
the comfort level of the recline once an adjustment is made.
[0060] The user determines his/her comfort level by moving the
lever forward or rearward while attempting to recline. When the
amount of resistance force is found to be suitable, the user
releases the handle portion 220 of the actuator lever 182. The wire
spring 256 returns the actuator lever to an at-rest position where
the bridge wall 234 is positioned over the lock ball 254 causing
the lock ball to be depressed into one of the six lock openings
103. This locks the crank 224, and the actuator lever 182, and
thereby the spring assembly 152, into position relative to the
rotation axis 142. The distance of the spring assembly from the
pivot axis defines the amount of resistance that the spring
assembly offers to oppose the rotation of the back assembly 12.
Movement of the actuator lever 182 and the spring assembly 152 is
shown in FIGS. 25, 26 and 27. Total linear movement of the spring
assembly may amount to about 0.75 inches.
[0061] The lock structure may take any of a number of forms. For
example, a lock structure may be formed by a detent arrangement
like that used with the actuator lever 184 as explained below in
relation to the detent recesses 168 in the slide plate 150. Or, a
lock structure may be formed of high friction material or friction
increasing surface textures. The rotation or recline force applied
by a chair user is somewhat oblique thereby creating a force
component acting in the direction of the rotation axis 142. The
greater the recline angle, the greater will be the force component.
The lock structure must be sufficient to resist the force component
and any one of various mechanisms may prove satisfactory.
[0062] It is also noted that the amount of force needed to compress
the spring 218 is a function of the distance between it and the
rotation axis 142. In addition, the further the distance from the
rotation axis, the greater must be the deflection or compression of
the spring to reach a desired recline. This greater compression
distance adds a component to the total force resisting recline of
the back assembly.
[0063] The chair 10 may also include a limit control apparatus 270,
FIGS. 4, 8, 10 and 28-33, for determining the extent of allowable
recline or to prevent any recline at all. There may be three limits
or stops which a chair user may select for limiting the amount of
rotation of the back assembly from zero degrees, no recline, for
tasking, to about 3.5 degrees for tasking or conferencing to about
7 degrees, full recline, for conferencing or lounging.
[0064] The limit control apparatus 270 may include an actuator
structure or lever 184 with a handle portion 274 and a link portion
276, a slide block 278, a brace 280 and a stepped abutment
structure 282. The link portion 276 has a first end portion 284
with a fastener receiving opening 286 connected to the handle
portion 274, and a second end portion 288 with a slot 290. The
fastener receiving opening accommodates a shoulder bolt 292, FIG.
10, to connect the actuator structure 272 to the box 74 through
hole 106 and to establish a pivot axis 294. The link portion 276
also includes a small foot 295 to engage the detent recesses 168 in
the slide plate 150 to ensure the proper location and retention.
The slide block 278 has a base portion 296, a pin 298, an
upstanding projection 300 and a rail 302. The rail 302 rides in the
lateral slot 174 of the slide plate 150, FIGS. 8 and 10. The pin
298 is received by the slot 290 of the link portion 276 for
transforming rotational motion of the handle portion 274 to linear
motion of the slide block 278. The brace 280 is affixed to the
frame members 46, 48 of the back assembly 12 and the stepped
abutment structure 282 is connected to the brace 280.
[0065] The upstanding projection 300 of the slide block 278 may
include an abutment surface 304, and the abutment structure 282
includes three complementing abutment surfaces 306, 308, 310, each
abutment surface of the abutment structure being at a different
elevation from the other two surfaces. The abutment surfaces are
generally horizontal when the chair is in an upright position,
however, because of the recline of the back assembly, the shorter
abutments topped by the surfaces 308, 310 are slanted at about 3.5
and 7 degrees, respectively so that contact is made along generally
the entire surfaces. It is noted that the abutment structure 282
may be mounted on the box and the slide block 278 may be mounted on
the back assembly 12, if found desirable.
[0066] In operation, the limit control apparatus 270 functions by
pivoting the handle portion 274 through a maximum arc of about 21
degrees about the pivot axis 294. Rotation of the handle portion is
translated to linear motion of the slide block 278 and moving the
slide block allows selective placement of the upstanding projection
300 opposite one of three abutment surfaces 306, 308, 310 of the
abutment structure 282. Because the abutment structure is affixed
to the back assembly 12, rotation of the back assembly is
selectively limited. When the abutment surface 306 of the abutment
structure 282 is aligned with the abutment surface 304 of the
upstanding projection 300, the back assembly will not be able to
recline. When the abutment surface 308 is aligned with the
upstanding projection 300, the back assembly will be able to be
reclined about 3.5 degrees. When the abutment surface 310 is
aligned with the upstanding projection 300, the back assembly will
be able to be reclined fully, about 7 degrees. The limit control
apparatus is very easy to operate, is very reliable and is
robust.
[0067] The tilt mechanism 50 is based on a four bar mechanism, and
may include a first or frame bracket 322, a second or backrest
bracket 324, a first or upper pair of links 326, 328, a second or
lower pair of links 330, 332, a first or upper pair of structures,
such as rods 334, 336, and a second or lower pair of structures,
such as rods 338, 340. The tilt frame bracket 322 is secured to the
frame members 44, 46 in any convenient fashion. The backrest
bracket 324 is connected to the support panel 42 and allows the
back to pivot in a plane generally perpendicular to longitudinal
axes 342, 344, 346, 348 of the rods in reaction to the movement of
a chair user's back.
[0068] The frame bracket 322 includes a first or upper pair of
holes 350, 352 and a second or lower pair of holes 354, 356. The
front upper rod 336 is pivotally connected to the frame bracket
through the upper holes 350, 352 such that the pivot axis 344 of
the rod 336 does not translate. The front lower rod 340 which is
pivotally connected to the frame bracket through the lower holes
354, 356, such that the pivot axis 348 of the rod 340 is also
restrained from translating. The frame bracket 322 may also include
a first or upper pair of cutouts in the form of curved slots 358,
360 and a second or lower pair of cutouts in the form of slots 362,
364.
[0069] The back bracket 324 includes a first or upper pair of holes
366, 368, a second or lower pair of holes 370, 372, a first or
upper pair of cutouts 374, 376 and a second or lower pair of
cutouts 378, 380. Each link 326, 328, 330, 332 includes a first or
front end portion 390, 392, 394, 396 and a second or rear end
portion 398, 400, 402, 404.
[0070] The front end portions 390, 392 of the upper links 326, 328
may include rod openings 410, 412 which receive the front upper rod
336. The rear end portions 398, 400 of the upper links 326, 328
includes rod openings 414, 416 which receive the rear upper rod
334. The front lower rod 340 is received by openings 418, 420 in
the front end portions 394, 396 of the lower links 330, 332 and the
rear lower rod 338 is received by openings 422, 424 in the rear end
portions 402, 404 of the lower links 330, 332.
[0071] The upper rear pivot axis 342 is allowed to travel within
the arc generally defined by the pair of upper curved slots 358,
360 in the upper portion of the frame bracket 322. The lower rear
pivot axis 346 is allowed to travel along an arc generally defined
by the pair of curved lower slots 362, 364 in the frame bracket
322. The upper front rod 336 moves in the cutouts 374, 376 of the
backrest bracket 324 and the lower front rod 340 moves in the
cutouts 378, 380 of the backrest bracket 324. The upper links 326,
328 are able to pivot about the pivot axis 344 and the lower links
330, 332 are able to pivot about the pivot axis 348. The pivot axes
344, 348 allow the upper pair of links 326, 328 to rotate about 40
degrees downwardly until limited by the ends of the upper slots
358, 360, and the lower pair of links 330, 332 also rotate about 40
degrees downwardly. At rest, the ends of the lower slots 362, 364
limit rotation of the backrest bracket 324. These rotations combine
to allow the backrest bracket 324 to pivot about 7 to 8 degrees in
a plane generally perpendicular to the pivot axes 342, 344, 346,
348. This creates a stable, wobble-free platform for the backrest
38.
[0072] The effect of the two-dimensional movement of the backrest
bracket 324 is that the chair back follows and supports the back of
the chair user with little shear so that there is little or no
"shirt pull" of the garment being worn by the chair user even when
the user fully reclines the back assembly. This rotational
adjustment feature of the back is very stable, passive and
functions with chair users of various sizes.
[0073] The above specification describes in detail a preferred
embodiment of the present invention. Other examples, embodiments,
modifications and variations will, under both the literal claim
language and the doctrine of equivalents, come within the scope of
the invention defined by the appended claims. For example,
different lever, link and mechanism designs are considered
equivalent structures and will also come within the literal
language of the claims. The same applies to the dimensions and
physical charcteristics mentioned as well as the amount of recline
and tilt. Still other alternatives will also be equivalent as will
many new technologies. There is no desire or intention here to
limit in any way the application of the doctrine of equivalents nor
to limit or restrict the scope of the invention.
* * * * *