Note: Descriptions are shown in the official language in which they were submitted.
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ITEM OF SEATING FURNITURE
An aspect of the invention relates to an item of seating
furniture with a carrying frame and a seat frame which is
displaceable in a sliding guide relative to the
carrying frame between a front working position and a
rear resting position and carries a seat surface, and
also with a frame, which is pivotably movable relative
to the seat frame and kinematically coupled to the seat
frame, for a backrest.
An item of seating furniture of this type is already
widely used in daily life, in particular in offices,
and thus forms part of the prior art on account of
obvious prior use. A key aspect of this is the
ergonomically beneficial switching between a hollow and
a round back during sitting. Supporting of the back in
all positions is, in particular, to be allowed. This is
achieved by a kinematic coupling of the seat surface to
the backrest which is held on a lateral frame element.
This frame element is guided in a connecting link guide
in such a way that the movement from the working
position into the rear resting position leads to a
backward inclination of the backrest and at the same
time to a lowering of the backrest. In the process, the
seat surface is at the same time moved along a
substantially horizontal plane.
In addition, the seat surface has at its trailing end a
vertically upwardly directed angled portion which is
positioned parallel before the backrest in the working
position, but encloses an acute angle with the backrest
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in the resting position. A cushion, which is connected
both to the backrest and to this angled portion, thus
experiences an additional inclination which differs
from the actual backrest.
DE 10 2007 012 728 Al relates to a passenger seat for
vehicles, in particular railway vehicles, with a seat
part and a backrest, the seat part being displaceable
in relation to a base frame, which is common with the
backrest, in the longitudinal direction of the seat
part. In this case, a forward displacement of the seat
part provides at the same time a backwardly directed
arching of the backrest in the lumbar vertebral region
as a support for a kyphosis position of the back, so
that the entire seat part surface is also still
available, although the lower part of the backrest
cushion is pulled forward. Likewise, in a passenger
seat of this type, a backward displacement of the seat
part at the same time intensifies the arching of the
backrest in the lumbar vertebral region as an
intensified lordosis support, as the backrest cushion
has in the lumbar vertebral region a backwardly
directed projection or an arching which then presses
against a part of the base frame in the backrest region
and thus causes a forwardly directed arching of the
backrest cushion.
DE 10 2006 056 928 B3 relates to a seat with a seat
panel and a backrest, the seat panel being connected by
a first connecting means to a base means and adjustable
in relation to the base means vertically and at the
same time in the inclination and in the longitudinal
direction of the seat. As a result, the two laterally
opposing front connecting levers and the two laterally
opposing rear connecting levers form a parallelogram
rod assembly between the base means and the seat panel,
the dimensions of the front and the rear connecting
levers allowing, during pivoting of the connecting
levers, the seat panel to be adjusted in relation to
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the base means from an at least approximately
horizontal position in the longitudinal direction of
the seat forward and upward and with its rear part
downward. At the same time, the backrest is adjusted
with its lower part forward and with its shoulder
portion backward.
A synchronizing mechanism for office chairs is also
known from DE 10 2007 021 782 B3. In this case, a base
carrier, on which on the one hand a seat carrier, which
is articulated to the base carrier and is pivotable
about a transverse axis, and on the other hand a
backrest carrier, which is also articulated to the base
carrier and is pivotable about a transverse axis, is
mounted, is placed on a chair column. The seat carrier
and backrest carrier are articulated in such a way that
a backward pivoting movement of the backrest induces a
downward lowering movement of the trailing edge of the
seat.
In DE 36 35 044 Al a compression spring, which is
clamped, for acting on the seat carrier counter to its
pivoting direction, between the base carrier and a
supporting lever which is pivotable with the seat
carrier, is provided as the spring arrangement.
DE 199 22 446 Al also relates to a synchronizing
mechanism for a correlated seat/backrest movement of an
office chair.
The previously known items of seating furniture of the
aforementioned type have been found to have the
drawback that although the seat surface is movable and
an ergonomically correct relative position between the
seat surface and the backrest can also be set, a
relative position, which automatically adapts to these
different seat positions, of individual partial regions
of the seat surface has in the past not been
implemented or taken into account in this regard.
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One aspect of the invention is based on the object of allowing a further
improved,
ergonomically and also orthopaedically advantageous sitting position to be
achieved
by means of a plurality of elements, which are movable relative to one
another, of the
seat surface. At the same time, the design complexity required for the
implementation should be kept comparatively low.
One aspect of the invention provides an item of seating furniture in which the
frame
carries a pelvic support which is arranged in the rear region of the seat
surface and is
inclined in the working position in relation to the plane of the seat surface,
and in
which a carrying element of the carrying frame extends into the region of the
backrest
and carries a thrust bearing on which the frame is supported in a displaceable
and
pivotably movable manner and the frame is connected, at a trailing end portion
of the
seat frame, to the seat frame by a joint. One aspect of the invention starts
in this
regard from the surprising finding that not only the shaping of the backrest
or the
displacement of the seat surface leads to an ergonomically and also
orthopaedically
advantageous sitting position, but also the division of the seat surface into
a larger
front seat surface region, which at the same time forms the main seat surface,
and
into a smaller region which is formed by the pelvic support and is at the
back, i.e.
adjacent to the backrest, allows a significant improvement in sitting posture.
In other
words, whereas the pelvic support does not perform any particular supporting
function in the resting position, it protrudes during a displacement of the
working
position, supports the pelvis in the process and exerts at the same time a
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pleasant compressive loading with a forward direction
of action, so that the undesirable backward slipping of
the buttocks region is prevented. At the same time,
this extremely advantageous effect is also achieved in
a comparatively simple manner in terms of technology,
that is to say in that the pelvic support is immovably
connected to the backrest and is pivoted jointly
therewith about a horizontal joint extending between
the front seat surface region and the pelvic support. A
connecting link guide for the frame is thus not
required. On the contrary, performing this optimum
movement requires merely the joint which not only
defines the pivoting movement, but also transmits the
sliding movement of the user from the seat surface to
the frame, in conjunction with the thrust bearing on
which the frame carries out a superimposed pivoting and
displacing movement. For this purpose, the thrust
bearing is arranged in a plane well above the seat
surface. The pelvic support can in this case have both
a supporting body, which, like the seat surface, is
covered by a common cushion element, and a separate
shaped part having a differing degree of hardness. The
joint is in this case arranged on both sides of the
seat surface and has a common physical or virtual pivot
axis. In particular, the joint has just a single degree
of freedom.
A particularly advantageous embodiment is also achieved
in that the pelvic support is arranged in an upwardly
inclined manner exclusively in its working position in
relation to the plane of the seat surface. As a result,
in the resting position, the pelvic support therefore
adjoins the seat surface in a flush manner, so that the
seat surface is in principle merely increased in size.
As the backrest moves into the front working position,
the pelvic support is erected and thus performs the
desired supporting function, in a manner comparable to
a wedge pillow known per se, as a result of the
oblique, backwardly rising shape, so that the pelvis
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and the loins are automatically tilted forward
slightly. This lifts the rib cage and the spinal column
is stretched, so that the pelvic and lumbar vertebral
region is greatly stress-relieved. It goes without
saying that a lowered position of the backrest can
additionally be provided in the resting position.
Furthermore, the angle of inclination can also be
adjustably designed. Depending on the individual
preference, the pelvic support can then lie in the
resting position in a common plane with the seat
surface.
A particularly simple and at the same time extremely
effective embodiment is achieved when the pelvic
support and the backrest are immovable relative to each
other during the movement between the working position
and the resting position. Thus, not only the backrest,
but also the pelvic support has a supporting effect
displacing the user of the item of seating furniture
forward. The invention thus overcomes the prejudice of
experts that holds that an invariable angle between the
seat surface and backrest must be avoided at all costs.
Furthermore, it is particularly expedient if the
backrest is immovable relative to the frame during the
movement between the working position and the resting
position relative to each other, whereas settability of
the backrest relative to the frame, including for
example in partial portions for generating desired
contourings, is conceivable and beneficial.
The frame has a region associated on the one hand with
the pelvic support, on the other hand with the
backrest. A variant in which the frame has an angular
element which is connected by its first leg to the
backrest and by its further leg to the pelvic support
has accordingly been found to be particularly simple.
Bcth the backrest and the pelvic support can be
exchangeably arranged on this angular element. In
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particular, this provides, irrespective of the
aesthetic configuration, an operative mechanism which
opens up a large number of areas of application.
Furthermore, a particularly simple configuration of the
present invention is achieved when the joint connecting
the frame to the seat frame is designed as a hinge
joint in order in this way to implement the desired
path of movement with low design complexity.
Furthermore, it has in practice proven advantageous if
the carrying frame forms a stop for the movement of the
backrest into the resting position, so that the
backrest rests, in the resting position in which an
elevated load acts, not just against the thrust bearing
but in addition also against the stop, for example in a
form-fitting manner. In addition, the stop, which is
inserted into the back of the backrest in a contour-
flush manner, stabilizes the lateral introduction of
force.
Another, likewise particularly promising modification
is provided in that the frame is laterally guided in a
guide, in particular in a profile, the frame
counteracting in the first place an undesirable lateral
displacement, i.e. transversely to the direction of
movement of the seat face. In addition, essential
bearing elements can in this way also be arranged so as
to be protected from external influences. In addition,
the guide can also form a sliding path for the frame,
so that the guide performs the function of the thrust
bearing, and a separate thrust bearing may be dispensed
with.
A particularly advantageous configuration of one aspect of
the present invention is achieved when the thrust bearing
can be secured in different positions and the distance
of the thrust bearing from the seat surface can thus be
set. For this purpose, the thrust bearing can be
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arranged on an adjustable flange which can also be
adjusted without tools by means of an adjusting means,
for example. Alternatively, the carrying element
carrying the thrust bearing can also be designed so as
to be able to be set relative to the carrying frame.
A fundamental advantage of one aspect of the invention also
consists in the fact that the complex adaptation to different
body weights that was required in the prior art is
dispensed with in accordance with the invention.
Nevertheless, it has in practice proven to be desirable
if the seat surface and/or backrest can be moved into
the resting position counter to the restoring force of
a spring element, so that the item of seating furniture
automatically assumes its upright working position when
the user stands up from it. For this purpose, the
spring can be designed as a simple coil spring and
integrated into the sliding guide of the seat surface.
The thrust bearing can be formed in a simple manner by
a mere bearing surface. A modification in which the
thrust bearing is designed as a sliding or roller
bearing and thus permits at the same time both a
displacement of the frame on the thrust bearing and a
pivoting movement about the thrust bearing is, on the
other hand, particularly expedient. In addition to ball
bearings, wheels or rollers, which can also be designed
in a profiled manner, as well as sliding bearings,
which can preferably have a friction-reducing coating,
made of PTFE for example, are also suitable for this
purpose.
Furthermore, a development in which the seat frame
carries a front seat cushion and the frame carries a
pelvic cushion, directly adjoining the front seat
cushion, of the pelvic support, thus providing an
appealing and high-quality aesthetic appearance, has
also proven particularly promising.
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The item of seating furniture may be embodied in a broad range of forms.
According
to a particularly advantageous configuration, the item of seating furniture
can be
designed as a working chair, office chair, waiting chair, for example in the
waiting
region of an airport, resting chair or else as the seat of a motor vehicle,
aircraft or rail
vehicle, as a treatment chair in the medical and therapeutic sector, and also
as a
hairdressing chair or the like, wherein pure resting armchairs can also
advantageously be equipped with the movement kinematics according to the
present
invention.
In accordance with an aspect of the invention, there is provided an item of
seating
furniture comprising: a carrying frame having a carrying element; a seat frame
having a seat surface; a backrest, wherein the carrying element extends into a
region
of the backrest; a sliding guide, wherein the seat frame is displaceable in
the sliding
guide relative to the carrying frame between a front working position and a
rear
resting position; a pelvic support disposed in a rear region of the seat
surface and
inclined in the front working position in relation to a plane of the seat
surface; a frame
configured to carry the pelvic support and pivotably movable relative to the
seat
frame and kinematically coupled to the seat frame; a thrust bearing configured
to
support the frame in a displaceable and pivotably movable manner, wherein the
carrying element is configured to carry the thrust bearing; and a joint
connecting the
frame to the seat frame at a trailing end position of the seat frame.
The invention allows various embodiments. In order to further clarify the
basic
principle of the invention, one of these embodiments is illustrated in the
drawings and
will be described hereinafter. In the drawings:
Fig. 1 is a schematic side view of an item of seating furniture according to
the
invention;
Fig. 2 is a schematic plan view onto a carrying frame and also a rotary mount
of the
item of seating furniture shown in Figure 1; and
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Fig. 3 is a schematic front view of the item of seating furniture shown in
Figures 1 and 2.
The item of seating furniture 1 according to the invention will be described
hereinafter
in greater detail with reference to Figures 1 to 3 which show the item of
seating
furniture 1 from different views. In order to improve understanding, the
cushion
elements have in this case not been shown. The item of seating furniture 1 has
a
carrying frame 2 which is constructed on a rotary frame 3 known per se. This
carrying frame 2 carries a seat frame 5 which is horizontally displaceable in
a sliding
guide 4 between a front working position (illustrated merely by dashed lines)
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to a rear resting position and has a seat surface 6
which may be seen merely in outline. The seat frame 5,
which is displaceable in one plane, is kinematically
coupled to a frame 7 which is pivotably movable
5 relative to the seat frame 5 and the carrying frame 2.
This frame 7 carries on the one hand a backrest 8, on
the other hand also a pelvic support 9 arranged in the
rear region of the seat surface 6. For this purpose,
the frame 7 has a frame element 10 which is designed as
10 an angled portion and is connected by a first leg to
the backrest 8 and by a further leg to the pelvic
support 9. As may be seen, this pelvic support 9 is
inclined in the working position in relation to the
plane of the seat surface 6 and thus protrudes from the
1.5 plane of the seat surface 6, whereas the pelvic support
9 is lowered in the resting position in relation to the
seat surface 6. The mechanism required for these
kinematics also comprises a carrying element 11 which
is connected to the carrying frame 2, extends into the
region of the backrest 8 and is equipped there with a
stop 12 for the resting position of the backrest 8. In
this region, a thrust bearing 13 for the frame 7 or the
backrest 8, which thrust bearing allows a superimposed
displacement and also a pivoting movement and is
embodied by a roller in the illustrated variant, is
arranged on the carrying element 11. The frame 7 is
accordingly on the one hand supported on this thrust
bearing 13, on the other hand connected at a trailing
end portion of the seat frame 5 to the seat frame by a
joint 14 designed as a hinge joint, so that an
inclination of the backrest from the working position
(illustrated by dashed lines) into the resting position
leads to an inclination and at the same time to a
lowering of the backrest 8, but also to a lowering of
the pelvic support 9, which is rigidly connected to the
backrest 8, and forward displacement thereof. In this
way, the seat surface 6 is also displaced forward on
account of the kinematic coupling. For individual
adaptation, the thrust bearing 13 can be secured in
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different positions corresponding to a plurality of
recesses 15 selectively receiving a fixing of the
thrust bearing 13 in order in this way to be able to
set the distance a of the thrust bearing 13 from the
seat surface 6. In this way, various ergonomically and
orthopaedically beneficial sitting positions are
implemented with low mechanical complexity.
