U.S. patent application number 11/772967 was filed with the patent office on 2008-01-17 for chair with seat and backrest with synchronised movement.
Invention is credited to Giancarlo Piretti.
Application Number | 20080012412 11/772967 |
Document ID | / |
Family ID | 37496876 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080012412 |
Kind Code |
A1 |
Piretti; Giancarlo |
January 17, 2008 |
CHAIR WITH SEAT AND BACKREST WITH SYNCHRONISED MOVEMENT
Abstract
Chair comprising a support base, a seat including a support
structure that is movable relative to the support base between a
lowered position and a raised position, and a backrest having a
support structure articulated to the support base around a
transverse axis and oscillating around said axis between a position
of maximum forward inclination and a position of maximum backward
inclination, in which the seat and the backrest are mutually
connected in such a way that when the backrest is in the position
of maximum forward inclination the seat is in the lowered position
and when the backrest is in the position of maximum backward
inclination the seat is in the raised position. The support
structure of the seat is connected to the support base by means of
at least one rocking lever articulated to the support base and to
the support structure of the backrest around two mutually parallel
transverse axes. The support structure of the backrest comprises
two lateral sections each of which has a connecting portion that
extends beyond the axis of articulation of the backrest to the
support base, the connecting portions being articulated to the
support structure of the seat around a transverse axis displaced
forward relative to the axis of articulation of the backrest.
Inventors: |
Piretti; Giancarlo;
(Bologna, IT) |
Correspondence
Address: |
PATTERSON & SHERIDAN, L.L.P.
3040 POST OAK BOULEVARD
SUITE 1500
HOUSTON
TX
77056
US
|
Family ID: |
37496876 |
Appl. No.: |
11/772967 |
Filed: |
July 3, 2007 |
Current U.S.
Class: |
297/341 |
Current CPC
Class: |
A47C 1/03277 20130101;
A47C 1/03238 20130101; A47C 1/03255 20130101; A47C 1/03233
20130101 |
Class at
Publication: |
297/341 |
International
Class: |
A47C 1/06 20060101
A47C001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2006 |
EP |
06425482.4 |
Claims
1. Chair comprising: a support base, a seat including a support
structure that is movable relative to the support base between a
lowered position and a raised position, and a backrest having
support structure articulated to the support base around a
transverse axis and oscillating around said axis between a position
of maximum forward inclination and a position of maximum backward
inclination, in which the seat and the backrest are mutually
connected in such a way that when the backrest is in the position
of maximum forward inclination the seat is in the lowered position
and when the backrest is in the position of maximum backward
inclination the seat is in the raised position, wherein: the
support structure of the seat is connected to the support base by
means of at least one rocking lever articulated to the support base
and to the support structure of the backrest around two mutually
parallel transverse axes, the support structure of the backrest
comprises two lateral sections each of which has a connecting
portion that extends beyond the axis of articulation of the
backrest to the support base, the connecting portions being
articulated to the support structure of the seat around a
transverse axis displaced forward relative to the axis of
articulation of the backrest.
2. Chair as claimed in claim 1, wherein it comprises an elastic
device tending to thrust the backrest towards its position of
maximum forward inclination and the seat towards the lowered
position, the elastic device comprising a transverse flexing bar
having a central portion that is fixed relative to the support base
and two ends connected to said connecting portions of the
backrest.
3. Chair as claimed in claim 2, wherein the flexing bar is
connected to the connecting portions of the backrest by means of
two vertical levers.
4. Chair as claimed in claim 2, wherein it comprises a device for
adjusting the stiffness of the flexing bar including two movable
pivot pins having respective transverse holes, mutually aligned,
through which the flexing bar extends.
5. Chair as claimed in claim 4, wherein the adjustment device
comprises two rods fastened to the respective movable pivot pins
and provided with respective racks meshing with a same
gearwheel.
6. Chair as claimed in claim 1, wherein the support base comprises
two lateral flanges extending upward whereto are articulated said
lateral sections of the support structure of the backrest.
7. Chair as claimed in claim 6, wherein the support structure of
the backrest comprises a transverse element provided with two
lateral vertical arms whose top ends are articulated to said
connecting portions of the backrest.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of European patent
application number 06425482.4, filed Jul. 11, 2006, which is herein
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a chair with seat and
backrest with synchronised movement.
[0004] More specifically, the invention relates to a chair
comprising a support base, a seat that is movable relative to the
support base between a lowered position and a raised position, and
a backrest articulated to the support base around a transverse axis
and oscillating around said axis between a position of maximum
forward inclination and a position of maximum backward inclination,
and in which the seat and the backrest are mutually connected in
such a way that when the backrest is in the position of maximum
forward inclination, the seat is in lowered position and when the
backrest is in the position of maximum backward inclination, the
seat is in the raised position.
[0005] 2. Description of the Related Art
[0006] Chairs of the type defined above are known in the field as
"weight-activated chairs". The weight of the user tends to push the
seat downward and tends to maintain the backrest in the position of
maximum forward inclination. When the user bears the weight
backwards on the backrest, the backward thrust is contrasted by the
weight of the user bearing down on the seat. Chairs of this kind
are normally provided with an elastic device which tends to thrust
the seat towards the lowered position and the backrest towards the
position of maximum forward inclination, so the backwards thrust on
the backrest has to overcome both the weight bearing down on the
seat and the elastic force which tends to maintain the backrest in
the position of maximum forward inclination.
SUMMARY OF THE INVENTION
[0007] The object of the present invention is to provide a chair of
the type indicated above having a simpler, more economical and more
compact structure than prior art chairs.
[0008] According to the present invention, said object is achieved
by a chair having the characteristics set out in claim 1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The chair according to the present invention shall now be
described in detail with reference to the accompanying drawings,
provided purely by way of non limiting example, in which:
[0010] FIG. 1 is a partial perspective view of a chair according to
the present invention,
[0011] FIG. 2 is an exploded perspective view of the part of chair
shown in FIG. 1,
[0012] FIGS. 3 and 4 are longitudinal sections according to the
line III-III of FIG. 1, showing the chair according to the
invention in two positions,
[0013] FIG. 5 is a partial cross section according to the line V-V
of FIG. 1, and
[0014] FIGS. 6 and 7 are bottom plan views of the chair according
to the invention.
DETAILED DESCRIPTION
[0015] With reference to FIGS. 1 and 2, the reference number 10
designates a chair according to the present invention. The chair 10
comprises a fixed support base 12, a seat 14 and a backrest 16.
[0016] The support base 12 comprises a transverse element 18 with a
channel shape, provided at its lateral ends with two flanges 20
extending upwards. The base 12 is connected to a vertical central
upright (not shown) with adjustable height, projecting upwards from
a support formed by a plurality of radial arms provided at their
outer ends with casters, according to an arrangement that is widely
known in the office chair industry.
[0017] The backrest 16 comprises a support structure 22 that bears
a shaped panel 24 to support the occupant's back. The support
structure 22 of the backrest 16 has two lateral sections 26 that
extend in the longitudinal direction. The two lateral sections 26
are articulated to the flanges 20 of the support base 12 around a
transverse horizontal axis 28. The two lateral sections 26 of the
backrest 16 are provided with transverse holes 30 with mutually
aligned axes, which are connected by means of trunnions (not shown)
to corresponding holes 32 provided at the top ends of the flanges
20 of the support base 12. The two lateral sections 26 of the
backrest 16 are provided with respective connecting portions 34
which extend forward relative to the articulation axis 28. The
connecting portions 34 are provided at their front ends with
transverse holes 36 with mutually aligned axes.
[0018] With reference still to FIGS. 1 and 2, the backrest 14
comprises a support structure 38 and a panel 40. The support
structure 38 in turn comprises a transverse element 42 and two
longitudinal elements 44 fastened to the transverse element 42. The
two longitudinal elements 44 have respective longitudinal guides
engaged by blocks 46 fastened to the lower part of the panel 40.
This arrangement enables to adjust the position of the panel 40 in
the longitudinal direction relative to the support structure 38.
One of the two blocks 46 is provided with an arresting device that
allows to lock the panel 40 in a pre-selected position,
disengageable by means of a lever 48.
[0019] The transverse element 42 of the support structure of the
backrest 38 is provided at its lateral ends with two vertical arms
50 that are fixed relative to the transverse element 42. The two
arms 50 are provided with respective holes with transverse axis 52.
The vertical arms 50 of the transverse element 42 are articulated
to the connecting portions 34 of the backrest 16 by means of two
pivot pins 54, each of which engages two aligned holes 36, 52. The
pivot pins 54 achieve an articulated connection between the
transverse element 42 of the support structure of the backrest 38
and the support structure of the backrest 22, around an axis
designated with the reference 56. The articulation axis 56 is
parallel and displaced forward relative to the articulation axis 28
between the backrest 16 and the support base 12.
[0020] The support structure of the backrest 38 is connected to the
support base 12 by means of two rocking levers 58. Each rocking
lever 58 has a first end articulated to the support base 12 and a
second end articulated to the support structure of the backrest 38.
More specifically, the second end of each lever 58 is articulated
to a respective longitudinal element 44 of the support structure of
the backrest 38. The axes of articulation of the levers 58 are
respectively designated by the references 60 and 62. Said axes are
mutually parallel and they are parallel to the axes of articulation
28 and 56 defined previously. In the example shown in the figures,
two levers 58 are provided, but a single lever 58 could also be
sufficient to achieve the same result.
[0021] With reference to the FIGS. 2 and 5, the support base 12
bears an elastic element constituted by a flexing bar 64. The
flexing bar 64 extends in the transverse direction, parallel to the
axes of articulation 28, 56. The ends of the flexing bar 64 extend
in the transverse direction beyond the transverse element 42 of the
support structure of the seat 38. Said ends engage respective holes
of two vertical levers 66. The top ends of the vertical levers 66
are articulated to the connecting portions 34 of the backrest 16.
In the embodiment illustrated in the figures, the top ends of the
levers 66 are articulated to the connecting portions 34 by means of
the same pivot pins 54 that connect in articulated fashion the
connecting portions 34 of the backrest 16 to the vertical flanges
50 of the support structure of the backrest 38. The flexing bar 34
can be constituted by a metal rod with any cross section, e.g.
circular, square, rectangular, etc. The flexing bar 64 could also
be formed as a leaf spring, with a plurality of mutually fastened
superposed strips. A central part of the flexing bar 64 is fastened
to the support base 12 whilst the lateral portions of the flexing
bar 64 can deform elastically relative to the fixed central
portion.
[0022] With reference to FIGS. 2 and 5, the support base 12
comprises two fixed pivot pins 68 and two movable pivot pins 70.
The pivot pins 68, 70 are provided with through holes with
transverse axis through which extends the flexing bar 64. The holes
of the pivot pins 68, 70 are mutually aligned and the movable pivot
pins 70 are positioned exteriorly in the transverse direction
relative to the fixed pivot pins 68. The movable pivot pins 70
extend through respective transverse slots 72 of the support base
12. The movable pivot pins 70 engage with play the flexing bar 64
and can be displaced relative to the support base 12 by means of an
adjustment mechanism that enables to move the pivot pins 70
jointly. The displacement of the pivot pins 70 varies the free
inflexion length of the lateral ends of the bar 64. Consequently,
displacing the movable pivot pins 70 varies the stiffness of the
flexing bar 64.
[0023] FIGS. 6 and 7 show an example of the adjustment mechanism
that controls the movement of the movable pivot pins 70. Each
movable pivot pin 70 is fastened to a respective adjustment rod 74.
The two rods 74 are positioned on the lower surface of the support
base 12 and have respective racks 76 that mesh with a same
gearwheel 78 freely rotatable around a vertical axis. One of the
two adjustment rods 74 is provided with an actuation grip 80. If
the grip 80 is moved in the transverse direction, the two rods 74
are jointly moved in the direction indicated by the arrows 82 in
FIGS. 6 and 7. FIG. 6 shows the condition in which the pivot pins
70 are in the outermost position, which corresponds to the maximum
stiffness of the flexing bar 64. FIG. 7 shows the condition in
which the pivot pins 70 are in the innermost position, which
corresponds to the maximum flexibility (or minimum stiffness) of
the flexing bar 74.
[0024] FIGS. 3 and 4 show the two extreme positions of the chair
according to the present invention. In the configuration shown in
FIG. 3, the flexing bar 64 is in non-deformed position. The
backrest 16 is in the position of maximum forward inclination and
the seat 14 is in its fully lowered position. The chair assumes
this configuration when it is not occupied by a user or when the
user sits on the seat 14 but exerts no backwards force on the
backrest 16.
[0025] FIG. 4 shows the backrest 16 in the configuration of maximum
backward inclination. The flexing bar 64 is in the condition of
maximum inflexion and the seat 14 is in the fully raised position.
This is the configuration assumed by the chair when the user bears
backwards on the backrest with all his/her weight. The rearward
thrust imparted by the user is contrasted by the weight of the user
on the seat 14 and by the return force of the flexing bar 64.
[0026] The connection between the seat 14 and the support base 12
is achieved by means of the rocking levers 58 and by means of the
connecting portions 34. The geometry of this connection is such
that the seat moves forward during its motion from the lowered
position to the raised position and, simultaneously, it changes its
inclination relative to a horizontal plane. This movement of the
backrest enables to obtain ideal conditions from the ergonomic
viewpoint in any position of the chair.
[0027] The use of a flexing bar 64 as an elastic element to return
the backrest 16 in the position of maximum forward inclination
enables considerably to reduce the dimensions of the support base
12. With an elastic organ constituted by a flexing bar, the
mechanism for adjusting the stiffness of the elastic organ also
becomes particularly simple.
[0028] In a possible variant, the ends of the flexing bar can be
connected to downward extensions of the vertical arms 50.
[0029] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *