Note: Descriptions are shown in the official language in which they were submitted.
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Title: "Chair
DO SCLQSURE:
This invention relates generally as indicated to a chair
and more particularly to a chair of the tilting type which but in
which the seat and back are mounted for limited tilting movement
both forwardly and rearwardly.
BACK 011~1D OF THE INVENTION
This invention relates to certain improvements in a chair
of the tilting type as shown and illustrated in applicant's prior
U.S. patent 4,429,917. The chair of such patent is known as the
flywheel chair and is marketed by SunarHauserman of Cleveland, Ohio.
Such chair utilizes a seat and back which tilt rearwardly in a
ratio of approximately 1 to 3. Some of the advantages of such
chair are that it eliminates the problem known as "shirt tail
pull" and that it may tilt back and return without lifting the
feet of the user from the floor. The approximate pivot point for
both the seat and back is at the ideal natural body pivot point of
the user even though the pivot point is not physically located in
such position
To, some task and executive applications, as well as in some
work station applications, particularly work stations involving
modern computer paraphernalia, it is desirable that the chair also
tilt forwardly to a limited decree. It is also desirable that the
chair incorporates some additional features of adjustment such as
the ability to adjust the width between the arm rests Chile
nonetheless maintaining the efficiencies of the noted seat and
back tilting both forwardly and rearwardly. It is desirable to
have a chair for executive, task or work station use which
literally can be tailored to the individual physical sizes of the
user.
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The present invention provides a chair useful
as an executive chair, a task chair, or at a specialized work
station such as utilized for computer or word processing tech-
neology. The chair may be of the swivel and tilting type and
includes a seat and back which may be supported on a vertically
adjustable pedestal. There is provided a linkage means supporting
the seat and back for both rearward and forwarding tilting
from a neutral position in which the seat is in a substantially
horizontal position.
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According to another aspect of the invention,
there is provided spring means supporting the seat in a stable
substantially horizontal position with linkage means supporting
the sea-t and back for limited forward and rearward tilting
against the pressure of the spring means.
The principal pivot position for the seat in its
relationship to the back is located on each side of the seat
and at substantially the ideal natural body pivot of the user
which is somewhat above the seat and forward of the back. The
back pivot may be located in the base at the top of the pedestal
and essentially vertically below such seat pivot. The link
supporting the back also supports such principal seat pivot.
The principal seat pivot may be rocked with the back supporting
link fore and aft the neutral position.
According to yet another aspect of the invention
there is provided a chair which includes a seat and a pivotal
support means for the sea-t above and on each side thereof.
Means is included -to rock the pivotal support means both fore
end aft a neutral position wherein the seat is substantially
horizontal. A seat cradle is pivotal suspended from -the
pivotal support means supporting the seat. The seat cradle
worms one link of linkage means operative to pivot the sea-t
inclined forwardly and also inclined rearwardly.
More specifically, the seat cradle is L-shaped
and is pivotal suspended from -the principal seat pivot and
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forms one link of a four-bar linkage, the opposite end of
the seat cradle being pivoted to a smaller front fink, in turn
pivoted to the base which forms the fixed link. The link sup-
porting the back and the principal pivot of the seat is also
pivoted to such fixed link. The arms are attached to the seat
cradle at such ideal natural body pivot and swing fore and
aft with the cradle.
In a specific embodiment of the invention a pair
I of opposed springs hold the chair in the neutral position.
Toe body weight of -the user in an ideal position also tends
to maintain the sea-t in such neutral position.
The described four-bar linkage provides a rearward
seat/back tilt ratio of about 1 to 3, and a more limited forward
sea-t/back tilt ratio of approximately 1 to 2, respectively.
With such tilt ratios the arms move in relationship with the
seat, being somewhat extended when the back reclines, and being
somewhat retracted when tilting forward. In addition to the
vertical adjustment of the base, the back may be adjusted Verdi-
gaily with respect to the seat, and a spring loaded shoulder
support may be
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provided at the top of the back. The seat may be adjusted fore
and aft on the seat cradle to adjust the seat depth. In addition,
removable, height adjustable arm rests may be provided mounted on
the principal pivots of the seat and for movement with the seat,
such arm rests being readily side-to-side interchangeable to widen
or narrow/ the distance therebet~een.
To the accomplishment of the foregoing and related ends the
invention then, comprises the features hereinafter fully
described and particular pointed out in the claims, the following
description and the annexed drawings setting forth in detail
certain illustrative embodiments of the invention, these being
indicative, however of but a few of the various ways in which the
principles of the invention may be employed.
BRIEF DESCRIPTION OF THE DRUNKS
In said annexed drawings:
Figure 1 is a side elevation of a chair in accordance with
the present invention shown in tilted back position;
Figure 2 is an enlarged side elevation of such chair with
certain parts omitted, and also, showing the forward and rearward
tilting of the seat and back in phantom line positions;
Figure 3 is a rear elevation of the seat seen from the line
3-3 of Figure 2, again with certain parts omitted for clarity of
illustration;
Figure 4 is a top plan view of the tilting mechanism as
seen from the line 4-4 of Figure 2 with the seat and back removed;
Figure 5 is an enlarged vertical section seen from the line
5-5 of Figure 4 illustrating one of the springs employed to
balance the seat and back in a neutral position;
Figure 6 is a similar section taken from the line 6-6 of
Figure 4 illustrating the other spring;
Figure 7 is a front elevation of a chair in accordance
with the present invention illustrating the arm rests in one
Usition of adjustment;
Figure 8 is a view similar to Figure 7 illustrating the arm
rests in an interchanged position or another position of
adjustment; and
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Figure 9 is a schematic side elevation illustrating the
four-bar linkage of the present invention and illustrating with
arrows the various adjustments which may be made with respect to
the chair and its components.
-E-rAILr-~D DESCRY SHEA OF THE P FURROWED En ODI~iE~TS
Referring first to Figure 1, it will be seen that the chair
comprises a base 10, a seat 11 and a back 12. The base is mounted
on a pedestal which includes an upright spindle 14 projecting
upwclrdly from a five-leyged frame adapted to support the chair on
a floor or carpet by the use of casters 16 at the end of each
leg. A pair of arm rests indicated generally at 17 and 18 may be
provided extending upwardly on each side of the seat and forwardly
of the back.
Initially it should be noted that the spindle 14, in
conventional manner, may include a gas spring lifter which
includes an upwardly projecting plunger 20 extending from the top
of the spindle through a protective boot 21. The gas spring
lifter may be operated by an actuator 22 at the side of the chair
seen more clearly in Figure 3 which engages a bypass valve through
a lever 23. In this manner, the vertical height of the chair may
readily be adjusted. Such gas spring lifters are conventional.
The plunger of the gas spring lifter is secured through a
wedge lock 25 seen in Figure 4 to the base 10.
The outline of the base in plan, as seen more clearly in
Figure 4 is generally T-shape and includes a vertically oriented
buck wall 27 at the rear of the base which extends completely
across the head of the T. The ends of the head of the T are
closed by end walls 28 and 29 which are in turn connected to
somewhat shorter walls 30 and 31, respectively forming the
underside of the head of the T as seen in Figure 4. Connected
both to such walls and to the back wall 27 are forwardly
projecting side walls 33 and 34.
Also extending forwardly of the back wall 27 are two
intermediate walls 35 and 36 which are welded to the hub 37
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housing the wedge lock 25 for the spring plunger 20. Such walls
are also interconnected by a rigidifying Hall 38 near the front of
the base.
The walls 35 and 36 also provide in cooperation with the
outer walls housing for springs 40 and 41, the function and
operation OX which will hereinafter be described. The walls 33
and 35 are interconnected by transverse walls 43 and I as well -s
the back wall 27, as seen more clearly in Figure 6. The walls 36
and I are interconnected by transverse walls 46 and 47, as well
as the back; wall 27, as seen more clearly in Figure 5. The Hall
structure above described for the springs and supporting the chair
on top of the gas spring plunger of the spindle comprises a
mechanism housing and may be fabricated of aluminum by weldments
or cast in metal as a single unit.
Extending through the fees of such base or housing is a
cross shaft 50 which may be mounted in the various vertical walls
within plastic bearings 51. As seen more clearly in Figures 3 and
4, the cross shaft extends somewhat beyond the ends of the head of
- the T as indicated at 53 and 54 and projects into the hubs 55 and
55 of back pivot arms 57 and 58, respectively. As indicated more
clearly in Figure 3, the projecting ends of the cross shaft within
the hubs may be flattened and secured in place by pairs of set
screws 60.
The pivot arms 57 and 58 may be in the form of an aluminum
weldment or castings, for example, and extend outwardly and
upwardly from beneath the seat 11 to horizontally aligned pivot
hubs 62 and 63. From such hubs the back pivots continue upwardly
extending initially rearwardly and inwardly as seen at 64 and 65
and then vertically upwardly as seen at 66 and 67. The seat back
may include a cushion shell shown generally at 69 to which the
upper ends of the back pivot arms are connected by fasteners 70
extending through vertically elongated slots 71. In this manner,
the seat back may be vertically adjusted. The seat back pivot
arms form from the cross shaft 50 to the center of hubs 62 and 63
the rear link of a four-bar linkage hereinafter more completely
c~e~cribed~
As indicated, the hubs 62 and 63 are slightly above the
seat bottom which is seen at 73 in Figure 2 and to each side
thereof. The centers of such hubs are fairly close to the natural
Buick pivot of the user. Each hub has journal Ed therein
horizontally extending spindles 75 and 76 which extend outwardly
from the tops of seat cradle hangers 77 and 78, respectively.
Such hankers are secured to the upwardly curved ends of a square
tube I and rerun such ends extend slightly outwardly and upwardly
to the spindle. The hangers may also have a slight dog leg to the
rear as seen in Figure 2. The square tube is curved upwardly to
support removably and adjustable a shell 81 of the seat 11. The
spindles 75 and 76 are the elements to which the arm rests are
connected.
As seen more clearly in Figure 3, the spindles 75 and 76
may be journal Ed in such hubs by shouldered plastic bushings then
secured in place by fasteners 83 and 84 extending into holes in
the spindles and extending through plastic thrust washers 850 The
fasteners I end 84 may also be used to secure removably in place
the arm rests 17 and 18~ Secured to the square tube and extending
forwardly therefrom are two angle members 87 and 88 which complete
the seat cradle. The two horizontally outwardly extending top
flanges of such angles may be employed also to secure removably
the seat shell 81 in place. Such adjustment may be obtained by
fasteners and slots.
In any event, the seat cradle is rigidly secured to the
seat shell which is in turn suspended from the pivots or ponytails
75 and 76. The seat cradle and arms, generally designated at 90
forlns a rigid L-shape link which is another link of such four-bar
linkage.
At its forward end, the seat cradle is pivotal connected
to the top of a relatively short front link 92, the sectional
configuration of which is more clearly shown in Figures 5 and 6.
The front link 92 includes a top hub 94 and a bottom somewhat
larger hub 95 interconnected by a front web 96.
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Tile top hub 94 is somewhat longer than the bottom hub an
projects over the top of the base side plates 33 and 34 as seen in
Figure 3. The front link is pivotal connected to the vertical
flanges of the angles 87 and 88 of the cradle 90 by fasteners 97.
The front link is also connected to the forwardly projecting side
plates of the base or spring housing by fasteners 98~ Such
fasteners may extend through suitable sleeve and thrust and
plastic bearings. In this manner, the front of the cradle is
pivoted to the top of the front lint which forms another link in
slush four-bar linkage.
The base or spring housing 10 which is fixed on top of
the gas spring plunger and pivotal connected to the front link
as well as a rear link forms the fourth bar of such four-bar
linkage.
Reverting now to the springs and operation thereof r it will
be seen that the spring 41 is compressed when the seat and back
are tilted rearwardly. As seen in Figure 5 there is secured to
the shaft 50 a spring actuator 99 which is clamped to such shaft
for rotation therewith by clamp fasteners 100. The spring
actuator induces a ball socket receiving the ball nose of spring
plunge. I which extends through the wall 47 and has secured
thereto on the opposite side of such plate a washer 103. The
spring plunger may be mounted in such plate on a plastic sleeve
bearing and an elastomeric stop 104 is provided between the plate
and the spring actuator. The spring actuator rocks with the shaft
50 and, as the shaft rocks in a clockwise direction as seen in
Figure 5, the spring 41 is compressed. when it rocks in the
opposite direction it disengages. The compression of the spring
may be adjusted by rotation of threaded stud 106 threaded in wall
I The stud includes a ball nose supporting spring retaining
washer 107 confining the opposite end of the spring 41.
erring now to Figure 6 it will be seen that the hub 95
ox the front link includes a projecting arm 110 which includes a
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bifurcated hook 111~ The hook 111 is designed to engage
transverse pin 112 on fixture 113 secured to the threaded end of
rod 114 extending through a plastic bushing 115 in the plate 43.
Tune opposite end of the rod is provided tooth adjustable lock nuts
117 which contain the spring 40 between the spring retainer 11
and the plate 43. Rotational movement of the front link in a
counter clockwise direction as seen in Figure 6 from the position
in Figure 6 will compress spring 40. Rotation in a clockwise
direction will permit the spring to extend and continued rotation
will permit the hook 111 to move away from the transverse pin 112.
Such springs maintain the seat of the chair in a
substantially horizontal or neutral position. Forward tilting of
the seat will cause -the spring 40 to be compressed while rearward
tilting of the seat will cause the spring 41 to be compressed.
Referring now to Figures 7 and 8, it will be seen that the
seat back 12 may be provided with an optional shoulder support
indicated at 120. The shoulder support may be vertically
adjustable mounted on a leaf spring or the like 121 from the shell
of the seat back.
Also indicated in Figures 7 and 8 are the interchangeable
positions of the arm rests 17 and 18. Such arm rests are mounted
on vertically extending arms or stanchions 123 and are laterally
offset and may be vertically adjustable secured thereto through a
multiple tooth or race and clamp mechanism. In this manner, the
height of the arm rests may be adjusted.
Such arm rests may be secured to the outside of the
spindles 75 and 76 simply by removing the fasteners 83 and 84 and
the associated washers.
In this manner the arm rests may readily be removed and
replaced and clamped in position. The angular position of the arm
rests with respect to a vertical axis or the horizontal
disposition of the seat may readily be in this manner adjusted if
required. Also, it will be noted that the arm rests may be
interchanged one for the other as seen in comparing Figures 7 and
8 so that a wider (Figure 7) or more narrow (Figure I dimension
is provided between interiors of such arm rests. The lower ends
of the arms of the arm rests are, of course, provided with
suitable holes through which the fasteners 83 and 84 may extend to
be locked to toe seat cradle spindles projecting through the
pivotal seat support. In this way the arms move in relationship
to the seat. The result is that as the seat tilts forward and the
back comes further forward less arm extends beyond the back rest
to interfere with a desk or table edge, whereas, in rear tilt more
arm is forward of the back rest
Referring now to figure 9, and in addition to Figure 2, it
will be seen that the spring balanced four-bar linkage provides
both forward and rearward tilting of the seat and back in a
desired ratio.
As the seat and back rock backwardly with the rocking of
the cross shaft 50 compressing the spring 41, the back may move to
the phantom line position seen at 130 in Figure 2. The seat pivot
for the suspended cradle also moves to the position 131 seen in
Figure 2 through the arc indicated at 132. As the spindles for
the seat support move rearwardly through such arc the front link
is drawn rearwardly through the arc 134 causing the seat to tilt
rearwardly and upwardly through the arc indicated by the arrows
135. As indicated such ratio is approximately on the order of 1
to 3 for a seat/back tilt ratio.
As the seat tilts forwardly, the back pivot arm moves
forwardly about the cross shaft 50 moving the seat to the phantom
line position 137 and moving the principal seat pivot support or
spindles through the arc 138 for rocking forward to the extent
indicated by the arrows 139. This then pivots the front link 92
forwardly through the arc 140 against the pressure of the spring
I tilting the seat forwardly and downward through the arc
indicated by the arrows 141. In the forward mode, the tilt ratio
of the back to the seat may be on the order of 2 to 1,
respectively.
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Ire specifically in the illustrated linkage, when the
seat tilts rearwardly it will move 18 and 30 ' tie the seat
tilts upwardly I In the forward tilting mode when the back
tilts forwardly 13 the seat will tilt downwardly 6 and 30 '.
Referring to Figure 9 there is illustrated schematically
the Eour-bar linkage which comprises the rear link 58, a top rigid
L-shape link 78, 88, a relatively short front link 92 and a fixed
or bottom link 10.
In addition, it will be seen that the seat back may be
adjusted vertically as indicated by the arrows 150. The arm rests
may be adjusted vertically as indicated by the arrows 151, and may
be adjusted angularly about the seat pivot spindles as indicated
by the arrows 152. moreover such arm rests 17 and 18 may be
interchanged as indicated by the arrows 153 to provide the more
narrow or wider seat seen in Figures 7 and 8. Also the entire
seat may be vertically adjusted through the gas spring as
indicated by the arrows 154. Also, the seat may be adjusted to
the front or rear in order to change seat depth in reference to
the back, as indicated by the arrows 155~ -
In any event, there is provided a seat which includes the
furrier linkage indicated which includes a fixed link 10 having
fixed pivots at each end. The front link pivots through the arc
156 in conjunction with the fore and aft pivot of the seat support
spindles indicated by the arc 157. The entire mechanism is
balanced in a neutral or a position wherein the seat is
substantially horizontal both by the weight of the user and by the
springs I and 41.
