Information
-
Patent Grant
-
6572191
-
Patent Number
6,572,191
-
Date Filed
Thursday, July 19, 200123 years ago
-
Date Issued
Tuesday, June 3, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Cuomo; Peter M.
- Harris; Stephanie
Agents
- Browdy and Neimark, P.L.L.C.
-
CPC
-
US Classifications
Field of Search
US
- 297 3007
- 297 3008
- 297 375
- 297 374
- 297 3002
- 297 3003
- 297 3001
- 297 373
- 297 4631
-
International Classifications
-
Abstract
A chair, in particular office chair, comprises a pedestal; a seat support supported thereon by a chair column and having front and rear seat support elements which are interconnected by a pivot axis; a seat supported on the seat support elements; a backrest fixed to the rear seat support element; and an adjustable-length energy storing device which is articulated to the seat support elements at a distance from the pivot axis thereof, sing for adjustment relative to each other of the backrest and the seat, with one seat support element being equipped with a receptacle for the upper end of the chair column. The receptacle on the seat support element is articulated to the seat support element by way of an articulated axis which is parallel to the pivot axis of the front and rear seat support element. The seat support element is provided with a rack detent arrangement which acts between the seat support element and the receptacle, arresting and releasing various inclinations of the seat support relative to the chair column.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a chair, in particular an office chair, comprising a pedestal; a seat support supported thereon by a chair column and having front and a rear seat support elements which are interconnected by a pivot axis; a seat supported on the seat support elements; a backrest fixed to the rear seat support element; an adjustable-length energy storing device, which is articulated to the seat support elements at a distance from the pivot axis thereof, serving for adjustment relative to each other of the back-rest and the seat; a receptacle, which is provided on a seat support element and lodges the upper end of the chair column, with the receptacle being articulated to the seat support element by way of an articulated axis that is parallel to the pivot axis of the front and rear seat support element; a detent arrangement, which acts between the seat support element and the receptacle, arresting and releasing various inclinations relative to the chair column of the seat support which is equipped with the receptacle.
2. Background Art
A chair of the generic type is known from U.S. Pat. No. 5,447,357. This chair has a front seat support element, in which is disposed a bearing element that can be pivoted in relation thereto. This pivoting helps adjust the inclination of the seat support relative to the chair column. For this pivoting motion to be arrested, provision is made for an arrangement of lamellar packs of mutually clamping action. In the pivoting direction, arresting takes place by frictional engagement. A drawback resides in that complete arresting cannot be ensured in the case of greater forces being exercised on the detent arrangement, for instance by heavyweight persons.
SUMMARY OF THE INVENTION
It is an object of the invention to further develop a chair of the generic type such that, regardless of the given adjustment in inclination by reason of the synchronous mechanism, the seat together with the backrest are as effectively fixable as possible in various inclined positions for the limit angles of inclination of the seat and backrest that are defined by the synchronous mechanism to be variable within a range of adjustment.
This object is attained by the feature according to which the detent arrangement is a rack detent arrangement. The gist of the invention resides in the provision of a rack detent arrangement, the advantage of which resides in that arresting in the pivoting direction takes place by positive locking instead of frictional engagement. In this way, especially efficient arresting is possible.
Additional features and details of the invention will become apparent from the ensuing description of an exemplary embodiment, taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of an office chair according to the invention;
FIG. 2
is a side view of the seat element base construction;
FIG. 3
is a cross-sectional view of the base construction on the line III—III of
FIG. 2
in the arrested position;
FIG. 4
is a view according to
FIG. 3
in the free pivoted position;
FIG. 5
is a view, on an enlarged scale, of a detail of
FIG. 3
; and
FIG. 6
is a view, on an enlarged scale, of a detail of FIG.
4
.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An office chair illustrated in
FIG. 1
comprises a pedestal
1
, supported via casters
2
on the ground. A chair column
3
adjustable in height and surrounded by bellows
3
a
is attached to the pedestal
1
. To the upper end of the chair column
3
a seat support
4
is detachably secured, on which an upholstered seat
5
is disposed. A backrest support
6
, which extends substantially upwards and to the upper end of which a backrest
7
is secured, is arranged on the seat support
4
. Height adjustment of the chair column
3
is performed by means of an operating lever
8
. For the purpose of changing the inclination of the backrest
7
together with backrest support
6
while simultaneously changing the inclination of the seat
5
, a further actuating lever
9
is mounted on the seat support
4
. The seat support
4
may be partially or substantially covered optically by a casing
10
arranged on the bottom side of the seat
5
. As can be seen from
FIG. 1
, the backrest support
6
is coated by bellows
11
for optical reasons.
The described basic construction of the office chair is generally known. The adjustable-height chair column
3
is known for instance from U.S. Pat. No. 3,711,054 or from U.S. Pat. No. 3,656,593. The construction of the seat support
4
including the described pivoting possibilities of backrest
7
and seat
5
is known for instance from U.S. Pat. No. 4,966,412.
As can be seen from
FIGS. 2 and 3
, the seat support
4
is divided. It consists of a front seat support element
12
and a rear seat support element
13
, which have a substantially U-shaped cross section which is open downwards. This results in that they comprise two side walls
14
,
15
or
16
,
17
, respectively, which are interconnected by bottoms
18
or
19
, respectively, facing the seat
5
. The two seat support elements
12
,
13
are interconnected by a pivot axis
20
that is arranged adjacent to their bottoms
18
,
19
.
On the front end of the seat support
4
, a seat holder
21
is arranged to be pivotable about a pivot axis
22
, the seat holder
21
being formed by a profile extending at right angles to the main plane of symmetry of the chair, i.e. at right angles to the plane of the drawing of FIG.
2
. On this seat holder
21
, the seat
5
is supported via spacers
23
.
The seat
5
is furthermore supported on, and secured to, the bottom
19
of the rear seat support element
13
by means of elastic buffers
26
On the rear end of the rear seat support element
13
, i.e. in the region where the backrest support
6
is secured to the rear seat support element
13
, a longitudinally adjustable energy storing device in tie form of a longitudinally adjustable gas spring
27
is articulated about a pivot axis
28
, which is parallel to the pivot axes
20
and
22
. The housing
29
of the gas spring
27
faces this pivot axis
28
, a piston rod
30
being extracted from the other end of the gas spring
27
. An actuating pin
31
, by means of which a valve that is located in the gas spring can be actuated for length adjustment, protrudes from the piston rod
30
. By means of a thread the piston rod
30
is connected with an actuating device
32
comprising the actuating lever
9
. This actuating device
32
is supported between the side walls
14
,
15
of the front seat support element
12
to be pivotable parallel to the pivot axes
20
,
22
,
28
. The actuating lever
9
is guided through and out of an oblong hole
33
in the associated side wall
16
of the rear seat support element
13
, this oblong hole being curved in such a manner that its center coincides with the pivot axis
20
. Any length adjustment of the gas spring
27
will result in the front seat support element
12
and the rear seat support element
13
being pivoted relative to each other about the pivot axis
20
, which on the one hand causes the inclination of the seat
5
to be changed and on the other hand the backrest support
6
with the backrest
7
to be pivoted simultaneously. Devices of this type are designated as so-called synchronous mechanisms. If he actuating pin
31
is pushed into the piston rod
30
of the gas spring
27
not just for a short time in order to achieve a change of length of the gas spring
27
and thus a change of the position of the seat
5
and the backrest
7
, but if the actuating pin
31
is pushed into the piston rod
30
for a prolonged time, then the seat
5
together with the backrest
7
can be tilted.
The construction of the seat support
4
with the seat
5
—as far as it has been described—is known from U.S. Pat. No. 4,966,412. The construction and arrangement of the actuating device
32
and of the gas spring
27
are known from U.S. Pat. No. 4,662,680.
A spring abutment
34
of angle-lever-type cross-sectional design is supported to pivot about the pivot axis
20
of the front and rear seat support element
12
or
13
, respectively. An abutment lever
35
extends from the pivot axis
20
backwards, i.e. in the direction towards the backrest support
6
, and that below the bottom
19
of the rear seat support element
13
.
By means of its external thread
37
, an adjusting screw
36
is arranged in an internal thread
38
on the abutment lever
35
in the vicinity of the free end thereof. The threads
37
,
38
are not self-locking. The free end of the adjusting screw
36
supports itself against the bottom
19
of the rear seat support element
13
.
The other abutment lever
39
, which extends approximately vertically of the lever
35
downwards from the pivot axis
20
, bears against a spring
40
formed by a block of elastic material, for example a celled polyurethane elastomer that is commercially available under the designation Vulkocell. The other end of this spring abuts against a stationary, however pivotable abutment
41
, which is formed by a rear wall, located opposite the lever
39
, of the bearing element
46
, which is described in detail below. The spring
40
is secured to a pin-like projection
42
of the lever
39
so that it cannot fall out downwardly from the region between the lever
39
and the abutment
41
.
If—as is shown in FIG.
2
—the external thread
37
of the adjusting screw
36
is completely screwed through the internal thread
38
of the spring abutment
34
, the abutment lever
39
is in its position next to the abutment
41
, i.e. the spring
40
is biased most strongly. Once again it is emphasized that the abutment
41
is arranged within the front seat support element
12
.
If, with the gas spring
27
unlocked, the backrest
6
is pivoted backwards, the portions located below the pivot axis
20
of the front and the rear seat support elements
12
or
13
, respectively, are pivoted towards each other, i.e. the spring
40
is compressed more strongly while this backward pivoting movement of the backrest
7
is progressively damped. This counterforce of the spring
40
thus progressively counteracts the backward pivoting motion of the backrest
7
. When the backrest
7
is relieved, its pivoting forward is assisted by a corresponding release of the spring
40
, this assisting force diminishing while the backrest
7
pivots forward.
If the adjusting screw
36
is screwed downwardly out of the abutment lever
35
so far that its pilot end
43
is approximately flush with the lever
35
, the spring
40
cannot be effective during the entire possible range of pivoting of the front and the rear seat support element
12
,
13
i.e., it is not pressed together between the abutment
41
and the abutment lever
39
while producing a corresponding counterforce.
In any intermediate positions of the adjusting screw
36
, the spring
40
is engaged in case of correspondingly varying pivoting positions of the rear seat support element
13
in relation to the front seat support element
12
, i.e. in the case of varying backward inclinations of the backrest
7
and thus of the seat
5
. In addition, in these intermediate positions, at first only an edge
44
of the block-like spring
40
rests on the abutment
41
, which contact steadily increases with a further pivoting motion for full-face rest on the abutment
41
. This gives also rise to the fact that a certain progression in the spring action is achieved.
For the spring abutment
34
per se being resistant to bending, the levers
35
,
39
are reinforced by one or more intermediate webs
24
. In order to prevent the adjusting screw
36
from being inadvertently screwed out of the internal thread
38
, its external thread is slit and pinched in usual manner in the vicinity of its end
43
. In order to permit easy operation of the adjusting screw
36
, it is provided with a twist handle
25
on its end protruding downwardly out of the seat support
4
. The adjusting screw
36
is displaced in relation to the gas spring
27
. The gas springs
27
are commercially available and are generally known with regard to construction and mode of operation for instance from U.S. Pat. No. 3,656,593.
For additional adjustment of inclination of the entire seat
5
with the synchronous mechanism, the front seat support element
12
is articulated to the upper end, forming a bearing cone
45
, of the chair column
3
via a bearing element designated as
46
in its entirety. The bearing element
46
of aluminum diecasting is seated by an internally cone-shaped bearing block
47
on the bearing cone
45
of the chair column
3
. The bearing block
47
is fastened in a longitudinally oriented rectangular tube
48
, which on its side located downstream of the bearing block
47
, supports an articulated axis
49
in the form of a simple screw and nut that is parallel to the pivot axis
20
. The front seat support element
12
is articulated to this articulated axis
49
.
For the seat
5
to be arrested in a certain inclined position, the front seat support element
12
is provided with a rack detent arrangement
49
a
which is disposed before the bearing block
47
, acting between the front seat support element
12
and the bearing element
46
. It has two parallel racks
50
,
51
which form a single piece with the bearing element
46
. The racks
50
,
51
stand back inwardly from the parallel outer walls
52
,
53
. The racks
50
,
51
are defined by guide walls
54
which are perpendicular to the indentations of the racks
50
,
51
. Provided on the free end of the bearing element
46
that is turned towards the pivot axis
22
is a stop edge
55
, which is parallel to the pivot axis
22
and cooperates with a stop
56
, which is joined to the seat support element
12
and has a plastic coating
57
. The pivotability of the seat support element
12
relative to the chair column
3
is defined by the stop edge
55
and the stop
56
. The detent arrangement
49
a
further comprises two parallel rack jaws
58
,
59
, which are substantially cuboid, having a jaw rack
60
and
61
on the side turned toward the racks
50
and
51
. The indentations the racks
60
and
61
are dimensioned such that they may engage with the indentations of the racks
50
and
51
i.e., they are parallel to, and uniformly spaced from, each other so that optimal indenting is possible. The racks
58
,
59
are received with play in the guide walls
54
which guide them laterally. The rack jaws
58
,
59
are held by a clamping bolt
62
, which may act on them by force in the direction of the racks
50
and
51
. Centrically, the rack jaws
58
,
59
have holes
63
,
64
for the clamping bolt
62
to pass through. Between the racks
50
,
51
, the bearing element
46
has an oblong hole
65
, which is substantially parallel to the clamping bolt
62
. On the—in FIG.
3
—left end of the clamping bolt
62
, provision is made for an actuation sleeve
66
, which encircles the clamping bolt
62
and which is fixed by a nut
67
and a shim
68
towards the free end of the clamping bolt
62
. The actuation sleeve
66
is displaceably guided through a drilled hole
69
in the side wall
14
. On the side tamed towards the rack jaw
58
, the actuation sleeve
66
has an annular groove
70
which engages with a corresponding recess of the rack jaw
58
. The rack jaws
58
and
59
are prestressed outwards in the direction of the side walls
14
and
15
by a helical compression spring
71
, which encircles the clamping bolt
62
. In the vicinity of the side wall
15
, the clamping bolt
62
is guided through an actuation block
72
with a drilled hole
73
for the clamping bolt
62
to reach through. The actuation block
72
is displaceably guided through a drilled hole
74
in the side wall
15
and has an annular groove
75
on the side turned toward the rack jaw
59
, the groove
75
meshing with a corresponding recess of the rack jaw
59
. The actuation sleeve
66
and the actuation block
72
serve as guide elements for the clamping bolt
62
.
In the vicinity of the—in FIG.
3
—right end of the clamping bolt
62
, provision is made for a clamping device
76
for the rack jaws
58
,
59
to be actuated by force in the direction of the racks
50
and
51
. The clamping device
76
comprises a main clamping body
77
, which cooperates with the actuation block
72
; an actuating lever
78
, which is connected with the main clamping body
77
; and a handle
79
, which is provided on the free end of the actuating lever
78
. The main clamping body
77
has two parallel side walls
80
of substantially cross-sectional shape. The side walls
80
are interconnected by a spreader
81
and a lever receptacle
82
, with the spreader
81
and the lever receptacle
82
being disposed in the vicinity of the two ends of the side walls
80
. The spreader
81
has a guide channel
83
which the clamping bolt
62
is passed through. Provided between the spreader
81
and the lever receptacle
82
is an actuating head
84
, which is disposed on, and connected with, the free end of the clamping bolt
62
and fixes the main clamping body
77
in a direction of clamping
85
. The side wall
15
is joined to a downwardly open guide section
86
of the cross sectional shape of a U. The guide section
86
has an upper wall
87
as well as two parallel guide walls
88
connected therewith. In the vicinity of its free end, the upper wall
87
has a web
89
sloping slightly upwards from the horizontal. The side walls
80
and the sides of the actuation block
72
that are turned towards the guide walls
88
are guided between the guide walls
88
with play and non-rotatably relative to the clamping bolt
62
.
On the side turned toward the main clamping body
77
, the actuation block
72
has a cam
90
with two flanks
91
and
92
defining the cam
90
laterally. On the side turned toward the actuation block
72
, the spreader
81
has a cam
93
with two flanks
94
,
95
defining it laterally. On the opposite side, the spreader
81
has a cam
96
with flanks
97
,
98
defining it. The guide channel
83
has the shape of two drilled holes that are misaligned by an angle so that pivoting of the spreader
81
out of the arrested position seen in
FIG. 3
about the clamping bolt
62
into the free pivoted position seen in FIG.
4
. The guide channel
83
is defined upwards by two channel walls
99
,
100
which are offset by an angle from each other. Downwards the guide channel
83
is defined by two channel walls
101
,
102
which intersect substantially at right angles. On the side turned toward the spreader
81
, the actuation head
84
has a cam
103
as well as flanks
104
and
105
that define the cam
103
laterally. On the side turned toward the actuation head
84
, the lever receptacle
82
has a projection
106
, which reduces the gap between the lever receptacle
82
and the actuation head
84
sufficiently far so that human extremities such as the fingers of playing children cannot be pushed in and get caught when the main clamping body
77
is pivoted.
The following is a description of the way of arresting of the bearing element
46
in relation to the front seat support element
12
and the subsequent release thereof, taken in conjunction with
FIGS. 3 and 4
and the details in
FIGS. 5 and 6
. The arrested position is illustrated in FIG.
3
and FIG.
5
. The actuating lever
78
is in the lower stop position. The spreader
81
is in the maximally spread position i.e., the actuation head
84
and the actuation block
72
are pressed apart as far as possible. In this position, the cam
96
rests on the flank
105
and the cam
93
on the flank
91
. In this position, the actuation block
72
forces the rack jaw
59
with the racks
61
into the racks
51
. The actuation sleeve
66
forces the rack jaws
58
with the racks
60
into the racks
50
. Pivoting the bearing element
46
relative to the seat support element
12
is not possible in this arrested position. For release of the arrest, the actuating lever
78
is pivoted upwards into the free pivoted position seen in FIG.
4
and partially in FIG.
6
. During the pivoting process, the cams
93
and
96
migrate along the cams
90
and
103
which abut there-against, with the block
72
and the head
84
moving further apart and the force of the spring
71
counteracting the pivoting motion. The point of contact of the cams
90
and
93
as well as
96
and
103
is a dead center position. Once the user has pivoted the actuating lever
78
beyond the dead center position, the lever
78
moves automatically into the free pivoted position seen in
FIGS. 4 and 6
. In this position, the side walls
80
bear against the web
89
. The cam
90
bears against the flank
94
and the cam
96
against the flank
104
. In this position, the distance A between the actuation head
84
and the actuation block
72
is smaller than in the arrested position seen in
FIGS. 3 and 5
. Consequently, the force acting on the rack jaws
58
and
59
in the direction toward the racks
50
and
51
is lower than it is in the arrested position so that the helical compression spring
71
can force the rack jaws
78
and
79
apart for them to disengage from the racks
50
and
51
. In the free pivoted position, the bearing element
46
can therefore be pivoted relative to the front seat support element
12
. The user of the chair has two possibilities of adjusting the inclination relative to the chair column
3
. On the one hand he can effectively arrest the inclination relative to the chair column
3
in a given position. A special advantage of the rack detent resides in that positive locking is obtained in the direction of pivoting i.e., substantially perpendicularly to the lengthwise extension of the racks
50
,
51
, so that even major forces for instance by heavyweight persons can be absorbed without any inadvertent adjustment of inclination. On the other hand, the arrest may be released. In this case, the optimal inclination relative to the chair column
3
as results from the user's seated position will be set automatically. This helps prevent the user from using a fixed inclination relative to the chair column
3
that might not be optimal anatomically. The seat
5
follows suit to any forward or backward inclination of the user.
Claims
- 1. A chair, in particular an office chair, comprising:a pedestal (1); a seat support (4) supported thereon by a chair column (3) and having a front and a rear seat support element (12, 13) which are interconnected by a pivot axis (20); a seat (5) supported on the front and rear seat support elements (12, 13); a backrest (7) fixed to the rear seat support element (13); an adjustable-length energy storing device (27), which is articulated to the front and rear seat support elements (12, 13) at a distance from the pivot axis (20) thereof, serving for adjustment relative to each other of the backrest (7) and the seat (5); a receptacle (47), which is provided on said front seat support element (12) and lodges the upper end of the chair column (3), with the receptacle (47) being articulated to the front seat support element (12) by way of an articulated axis (49) that is parallel to the pivot axis (20) of the front and rear seat support elements (12, 13); and a detent arrangement, which acts between the front seat support element (12) and the receptacle (47), arresting and releasing various inclinations relative to the chair column (3) of the seat support (4) which is equipped with the receptacle (47); wherein the detent arrangement is a rack detent arrangement (49a) which comprises: two racks (50, 51) which are joined to the receptacle (47); two rack jaws (58, 59) which are joined to the front seat support element (12), cooperating with the two racks (50, 51); said two racks (50, 51) and said two rack jaws (58, 59) to be intermeshed in pairs; wherein the two rack jaws (58, 59) are displaceably disposed on a clamping bolt (62).
- 2. A chair according to claim 1, wherein the rack detent arrangement (49a) comprises a clamping device (76) for arresting and releasing the rack detent arrangement (49a).
- 3. A chair according to claim 2, wherein the clamping device (76) is pivotable between a first stop position and a second stop position.
- 4. A chair according to claim 3, wherein, between the first stop position and the second stop position, the clamping device (76) passes a dead center position.
- 5. A chair according to claim 1, wherein the front seat support element 12 comprises drilled holes (69, 74), in which guide elements (66, 72) are displaceably guided, housing the clamping bolt (62).
- 6. A chair according to claim 1, wherein the rack detent arrangement (49a) comprises a helical compression spring (71) for the rack jaws (58, 59) to be forced apart.
- 7. A chair, in particular an office chair, comprising:a pedestal (1); a seat support (4) supported thereon by a chair column (3) and having a front and a rear seat support element (12, 13) which are interconnected by a pivot axis (20); a seat (5) supported on the front and rear seat support elements (12, 13); a backrest (7) fixed to the rear seat support element (13); an adjustable-length energy storing device (27), which is articulated to the front and rear seat support elements (12, 13) at a distance from the pivot axis (20) thereof, serving for adjustment relative to each other of the backrest (7) and the seat (5); a receptacle (47), which is provided on said front seat support element (12) and lodges the upper end of the chair column (3), with the receptacle (47) being articulated to the front seat support element (12) by way of an articulated axis (49) that is parallel to the pivot axis (20) of the front and rear seat support elements (12, 13); and a detent arrangement, which acts between the front seat support element (12) and the receptacle (47), arresting and releasing various inclinations relative to the chair column (3) of the seat support (4) which is equipped with the receptacle (47); wherein the detent arrangement is a rack detent arrangement (49a) which comprises: two racks (50, 51) which are joined to the receptacle (47); two rack jaws (58, 59) which are joined to the front seat support element (12), cooperating with the two racks (50, 51); said two racks (50, 51) and said two rack jaws (58, 59) to be intermeshed in pairs; wherein the two rack jaws (58, 59) are displaceably disposed on a clamping bolt (62); and wherein the rack detent arrangement (49a) comprises spring means (71) for forcing apart the rack jaws (58, 59).
- 8. A chair according to claim 7, wherein the rack detent arrangement (49a) comprises a clamping device (76) for arresting and releasing the rack detent arrangement (49a).
- 9. A chair according to claim 8, wherein the clamping device (76) is pivotable between a first stop position and a second stop position.
- 10. A chair according to claim 9, wherein, between the first stop position and the second stop position, the clamping device (76) passes a dead center position.
- 11. A chair according to claim 7, wherein the front seat support element (12) comprises drilled holes (69, 74), in which guide elements (66, 72) are displaceably guided, housing the clamping bolt (62).
Priority Claims (1)
Number |
Date |
Country |
Kind |
100 33 418 |
Jul 2000 |
DE |
|
US Referenced Citations (10)
Foreign Referenced Citations (6)
Number |
Date |
Country |
4014154 |
Nov 1991 |
DE |
0 584 620 |
Mar 1994 |
EP |
0 698 358 |
Feb 1996 |
EP |
0 995 371 |
Apr 2000 |
EP |
1 597 474 |
Sep 1977 |
GB |
WO 9945823 |
Sep 1999 |
WO |