U.S. patent application number 11/926618 was filed with the patent office on 2008-11-06 for synchronization mechanism.
This patent application is currently assigned to BOCK 1 GMBH & CO. KG. Invention is credited to Hermann Bock.
Application Number | 20080272638 11/926618 |
Document ID | / |
Family ID | 42224184 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080272638 |
Kind Code |
A1 |
Bock; Hermann |
November 6, 2008 |
Synchronization Mechanism
Abstract
A synchronization mechanism for a correlated movement of a seat
and a backrest of an office chair contains a basic support
placeable on a chair post, a seat support and a backrest support.
To provide a synchronization mechanism for which an adjustment of a
spring tension to change the "tilting resistance" of the backrest
is not required, a mechanism is proposed whereby the backrest
support that is pivotable around a swivel axis is directly linked
in a pivotable manner to the basic support, and to the rear end
section of the seat support, such that a backward tilt of the
backrest induces a lifting of the rear area of the seat support.
The seat support is so linked to the basic support as to cause a
lifting of the front area of the seat support when the user of the
office chair "lifts" him/herself up by leaning against the
backrest.
Inventors: |
Bock; Hermann; (Pyrbaum,
DE) |
Correspondence
Address: |
LERNER GREENBERG STEMER LLP
P O BOX 2480
HOLLYWOOD
FL
33022-2480
US
|
Assignee: |
BOCK 1 GMBH & CO. KG
Postbauer-Heng
DE
|
Family ID: |
42224184 |
Appl. No.: |
11/926618 |
Filed: |
October 29, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/EP2006/003655 |
Apr 21, 2006 |
|
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11926618 |
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Current U.S.
Class: |
297/316 |
Current CPC
Class: |
A47C 1/03255 20130101;
A47C 1/03272 20130101 |
Class at
Publication: |
297/316 |
International
Class: |
A47C 3/00 20060101
A47C003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2005 |
DE |
DE102005020237.3 |
Claims
1. A synchronization mechanism for a correlated movement of a seat
and a backrest of an office chair, the synchronization mechanism
comprising: a basic support placeable on a chair post; a seat
support having a rear end section; and a backrest support pivotable
around a lateral axis and directly linked in a pivotable manner to
said basic support and to said rear end section of said seat
support, such that a backward tilt of said backrest support induces
a lifting of a rear area of said seat support and said seat support
linked to said basic support as to cause a simultaneous lifting of
a front area of said seat support during the backward tilt of said
backrest support.
2. The synchronization mechanism according to claim 1, further
comprising a guiding connecting said basic support to said seat
support.
3. The synchronization mechanism according to claim 2, wherein said
guiding is a linear guiding.
4. The synchronization mechanism according to claim 1, wherein, as
seen in a longitudinal direction of the office chair, a swivel axis
of a connection of said backrest support to said basic support is
fitted behind a hinge axis of a connection of said backrest support
to said seat support.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuing application, under 35 U.S.C. .sctn.
120, of copending international application PCT/EP2006/003655,
filed Apr. 21, 2006, which designated the United States; this
application also claims the priority, under 35 U.S.C. .sctn. 119,
of German patent application DE 10 2005 020 237.3, filed Apr. 28,
2005; the prior applications are herewith incorporated by reference
in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a synchronization mechanism for a
correlated movement of a seat and a backrest of an office chair
containing a basic support placed on a chair post, a seat support
and a backrest support.
[0003] The term "synchronization mechanism" describes assemblies in
the substructure of an office chair seat, such assemblies provide
the interlinked kinematics that bring about certain relative
movements of the seat and the backrest. The, generally upholstered,
seat is mounted on the seat support of the office chair. The
backrest support that usefully extends backwards from the actual
synchronization mechanism supports the backrest of the office chair
on an upright cantilever. The seat support and the backrest support
are usually flexibly coupled so that a backward tilt of the
backrest--caused e.g. by a chair user leaning against the
backrest--induces a lowering of the rear edge of the seat.
[0004] In order to change the "tilting resistance" of the backrest,
such synchronization mechanisms usually incorporate spring
assemblies for pre-stressing the synchronization mechanisms. The
pre-stress level depends inter alias on the weight of the chair
user.
BRIEF SUMMARY OF THE INVENTION
[0005] It is accordingly an object of the invention to provide a
synchronization mechanism which overcomes the above-mentioned
disadvantages of the prior art devices of this general type, for
which an adjustment of the spring tension to change the "tilting
resistance" of the backrest is not required.
[0006] With the foregoing and other objects in view there is
provided, in accordance with the invention, a synchronization
mechanism for a correlated movement of a seat and a backrest of an
office chair. The synchronization mechanism contains a basic
support placeable on a chair post, a seat support having a rear end
section, and a backrest support pivotable around a lateral axis and
directly linked in a pivotable manner to the basic support and to
the rear end section of the seat support, such that a backward tilt
of the backrest support induces a lifting of a rear area of the
seat support and the seat support linked to the basic support as to
cause a simultaneous lifting of a front area of the seat support
during the backward tilt of the backrest support.
[0007] It involves a system whereby the backrest support that is
pivotable around a lateral axis is directly linked in a pivotable
manner to, on the one hand, the basic support and, on the other,
the rear end section of the seat support in such a manner that a
backward tilt of the backrest induces a lifting of the rear area of
the seat support. At the same time, the seat support is so linked
to the basic support as to cause a lifting of the front area of the
seat support.
[0008] A basic idea of the invention is that the user of the office
chair "lifts" him/herself up by leaning against the backrest. No
spring tension adjustment controls as known from the prior art
involving intricate control mechanisms (worm gears, cogwheels,
threaded rods etc.), are required. This significantly reduces the
manufacturing costs of the synchronization mechanism. At the same
time it increases the reliability.
[0009] Due to the fact that the seat support is lifted not only in
its rear area but that a lift of the front area of the seat support
occurs at the same time, a synchronous simultaneous upward and
backward movement of the seat in a predefined relation to the
backrest takes place. Due to the chosen configuration, the opening
angle of the backrest can be quite wide compared with the solutions
known from the prior art. Thus, extreme back positions are possible
as well.
[0010] Of special advantage is a configuration where the basic
support is connected to the front end of the seat support via a
linear guide. This facilitates a synchronized linear movement of
the seat with the backrest. Apart from linear guides with
straight-lined guide tracks, different guide tracks are naturally
also possible. The configuration of the guide, the position of the
guide (e.g. the inclination of the guide in relation to the
horizontal) etc., facilitate an individual adaptation of the
synchronized movement of the seat support. It is, for instance,
possible for the seat support to move synchronously with the
backrest in an absolutely linear fashion, without any "tilting" at
all. A suitable configuration of the guide also permits a slight
"tilting". Other variations can be achieved by positioning the
connection point between the basic support and the seat support at
smaller or greater distances from the front edge of the seat.
[0011] When the office chair has a seating area configured so that
a user imitates any tilting movement of the backrest to a position
further back, the so-called "shirt stripping effect" can be
prevented very effectively as well.
[0012] The lever geometry required for the "self-adjusting"
mechanism of the present invention is achieved preferably by a
configuration whereby the swivel axis of the connection between the
backrest support and the basic support, seen in longitudinal
direction of the chair, is positioned behind the hinge axis of the
connection between the backrest support and the seat support.
[0013] Although, according to the invention, no adjustment of the
spring tension is required, a device for adjusting the working area
can be provided. This is achieved in an advantageous manner by a
spring element disposed preferably in an generally horizontal
position in the seat support, such spring element being connected
to, on the one hand, the seat support and, on the other, a bearing
axle that is positioned crosswise and linked to the basic support.
The bearing axle has an eccentric configuration so that by turning
it, the user will cause a displacement of the axle center and thus
a change in the spring suspension, thereby facilitating an
adjustment between at least two spring tension settings
("hard"/"soft").
[0014] Compared with the solutions known from the prior art, the
invention introduces a constructively very simple swivel mechanism.
This reduces the manufacturing costs. Moreover, despite its simple
construction, it significantly reduces the so-called
"shirt-stripping effect". In order words, a very high degree of
sitting comfort is achieved without having to resort to complicated
and expensive solutions.
[0015] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0016] Although the invention is illustrated and described herein
as embodied in a synchronization mechanism, it is nevertheless not
intended to be limited to the details shown, since various
modifications and structural changes may be made therein without
departing from the spirit of the invention and within the scope and
range of equivalents of the claims.
[0017] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0018] FIG. 1 is a diagrammatic, rear perspective view of a
synchronization mechanism according to the invention;
[0019] FIG. 2 is a cross-sectional view of the synchronization
mechanism;
[0020] FIG. 3 is a top, rear perspective view of the
synchronization mechanism; and
[0021] FIG. 4 is a cross-sectional, top view of the synchronization
mechanism.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Referring now to the figures of the drawing in detail and
first, particularly, to FIG. 1 thereof, there is shown a
synchronization mechanism that features a basic support 1 to be
fitted to a top end of a non-illustrated chair post by a taper
socket 2. The synchronization mechanism contains a frame-shaped
seat support 3 (see FIG. 3) and in top view a fork-shaped backrest
support 4, the cheeks 5, 6 of which are disposed on both sides of
the basic support 1. All the drawings show the basic position where
the backrest support 4 has a generally vertical position.
[0023] A seat 7 with an upholstered surface is mounted on the seat
support 3. It is assembled in the customary manner with fastening
elements not shown in detail here. The seat 7 is secured firmly to
the seat support 3 so that any movement of the seat support 3 will
cause a corresponding movement of the seat 7.
[0024] Fitted to the backrest support 4 is a backrest, not shown in
detail, which in modern office chairs is height-adjustable. The
backrest can also be connected with the backrest support 4 as a
single unit.
[0025] As can be seen from the illustrations, the whole
synchronization mechanism, insofar as the actual kinetics are
concerned, is configured in mirror symmetry in relation to a
central longitudinal plane M (see FIG. 4). The following
description therefore always relates to pairs of the structural
elements of the swivel mechanism.
[0026] The backrest support 4 is attached on the one hand to a
swivel bearing 8 on the basic support 1, so that the backrest
support 4 is directly hinged to the basic support 1 via a swivel
bearing 8. As a result the backrest support 4 with the actual
backrest can be tilted in tilting direction S around the swivel
axis 9 running through the swivel bearing 8, see FIG. 2. The swivel
bearing 8 is formed in front of a front edge 10 of the cheek 5,
6.
[0027] On the other hand, the backrest support 4 with the front
edge 10 of its cheek 5, 6 is connected via a hinge 11 to a rear end
section 12 of the seat support 3. Thus, as a result of a backward
tilt of the backrest the seat support 3 is carried along in tilting
direction S and also lifted due to the lever arrangement formed by
the cheek 5, 6. In other words, there is a swing around an axis 13
of the hinge 11.
[0028] As seen in a longitudinal direction 14 of the chair, the
swivel axis 9 of the connection of the backrest support 4 to the
basic support 1 is fitted behind the hinge axis 13 of the
connection of the backrest support 4 to the seat support 3.
Moreover, the hinge axis 13 of the connection of the backrest
support 4 to the seat support 3 is situated above the position of
the swivel axis 9 of the connection of the backrest support 4 to
the basic support 1.
[0029] The basic support 1 contains two wings 16, 17 running in the
direction of a seat support front edge 15. As can be seen in FIG.
3, the wings 16,17 are each guided in a linear sliding guide 18 of
the front area of the seat support 3 and connected to one another
by a bearing axle 19.
[0030] Due to this design, it is not only the rear area of the seat
support 3 that experiences a lift H1 when pressure is placed on the
backrest and the backrest support 4 tilts back downwards in tilting
direction S, see FIG. 2. In addition, the front area of the seat
support 3 is lifted in a synchronous manner (lift H2). In other
words, there is a simultaneous lift of both the front and the back
of the seating area. The seat 7 is lifted in its entirety.
[0031] The padding 20 of the seating surface, see especially FIG.
2, is made of formed foam. It is divided into two different seating
areas 21, 22, arranged behind one another in longitudinal direction
14 of the seat and differing with regard to their upholstering.
With the form of seating surface used in the present example, the
front seating area 21, which constitutes about 30% to 40% of the
total length of the upholstery 20, is fitted with "standard"
upholstery thickness, while the rear seating area (between 70% and
60% of the total length) is fitted with variable upholstery that
permits the user to sink in towards the back by way of rolling
back. In the example shown, the upholstery thickness of the rear
seating area 22 is higher by at least 20 mm compared with the
upholstery thickness of the front seating area 21. The manner of
transition from the front seating area 21 to the rear seating area
22 is preferably very soft and smooth without any ridges.
Particularly good results are achieved with a transition area in
the form of an elongated horizontal S.
[0032] The transition from the front seating area 21 to the rear
seating area 22 is so arranged that the user in a normal
("average") seating position will put his weight mainly on the
front seating area 21. When pressure is put on the backrest, the
user's pelvis rolls over the horizontal S into the rear seating
area 22. The user thus follows the movement of the backrest back
downwards. In other words, the user's backward movement and the
connected pressure on the seat 7 in the rear area leads to a
"yielding" of the seat and with it a gliding into the upholstery 20
by the user in the form of rolling. A highly synchronized sequence
of movements between the backrest and the user is achieved in this
way. The so-called "shirt stripping" effect can be significantly
reduced as a result.
[0033] The foam is preferably free towards the rear seating surface
end 23 so that it can expand backwards. To achieve this, an open
design of the upholstery 20 without any bordering elements at the
back is preferred.
[0034] The concept `upholstery` is understood to mean any type of
flexible design of the seating surface, regardless of the material
used. Apart from formed foams, any other elastic materials may be
employed, such as spring packets, or combinations of materials,
such as e.g. foam in conjunction with silicon cushions. The use of
e.g. dual zone foam is possible as well.
[0035] The firmness of the "tilting resistance" of the backrest in
the example shown can be switched between two stages from "hard" to
"soft". For this purpose, a tension spring 24 fitted in a generally
horizontal position in the seat support 3 is provided, which with
its front end 25 is attached to the eccentric bearing axle 19 and
with its rear end 26 to the seat support 3. The bearing axle 19 can
be turned around its axis from a first to a second position by an
operating element 27 fitted at the side (see FIG. 4). Due to the
eccentric design of the bearing axle 19, see FIG. 4, the position
of the front attachment of the tension spring 24 is changed as well
when the bearing axle 19 is turned. The initial stress of the
tension spring 24 changes accordingly. Thus, a more or less firm
tilting resistance is achieved relative to the position of the
bearing axle 19. The number of tension springs 24 is not restricted
to one. Depending on the design, further tension springs 24 can be
fitted in parallel.
[0036] To arrest the inclination of the backrest, there is
obviously a mechanism provided, which is not described in detail
here but which is operated by a lever 28.
* * * * *