U.S. patent application number 12/306738 was filed with the patent office on 2010-12-02 for back rest for a stool or a chair, and stool or chair provided with such a back rest.
This patent application is currently assigned to ROHDE & GRAHL GMBH. Invention is credited to Martin Ballendat.
Application Number | 20100301652 12/306738 |
Document ID | / |
Family ID | 41078738 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100301652 |
Kind Code |
A1 |
Ballendat; Martin |
December 2, 2010 |
Back Rest for a Stool or a Chair, and Stool or Chair Provided with
such a Back Rest
Abstract
The invention relates to a back rest for a stool or a chair,
comprising two adjacent, spring-mounted back supports (3.1), each
of which is fixed to a separate carrier part (4.1). Said back rest
is characterised in that each carrier part (4.1) forms the first
limb of an essentially L-shaped carrier (4), and the second limb
(4.2) of each carrier (4) is fixed beneath the stool or chair seat
in such a way that it can be pivoted about a horizontal axis
against an elastic force.
Inventors: |
Ballendat; Martin; (Weng im
Innkreis, AT) |
Correspondence
Address: |
GUDRUN E. HUCKETT DRAUDT
SCHUBERTSTR. 15A
WUPPERTAL
42289
DE
|
Assignee: |
ROHDE & GRAHL GMBH
Steyerberg
DE
|
Family ID: |
41078738 |
Appl. No.: |
12/306738 |
Filed: |
May 26, 2007 |
PCT Filed: |
May 26, 2007 |
PCT NO: |
PCT/DE2007/000954 |
371 Date: |
August 24, 2010 |
Current U.S.
Class: |
297/303.1 ;
297/285 |
Current CPC
Class: |
A47C 7/402 20130101;
A47C 7/441 20130101; A47C 7/405 20130101; A47C 7/443 20130101; A47C
7/448 20130101 |
Class at
Publication: |
297/303.1 ;
297/285 |
International
Class: |
A47C 1/024 20060101
A47C001/024; A47C 3/00 20060101 A47C003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 29, 2006 |
DE |
10 2006 030 018.1 |
Claims
1.-31. (canceled)
32. A backrest for a stool or a chair, the backrest comprising: a
first and a second substantially L-shaped support members each
comprised of a first leg and a second leg, wherein the first legs
form a carrier part, respectively; a first and a second back
supports each arranged in a springy fashion and arranged laterally
adjacent to one another; wherein the first and second back supports
are attached to the carrier parts; wherein the second legs are
attached below a seat of the stool or the chair so as to be
pivotable against a spring force about a horizontal pivot axis;
wherein the first and second support members are connected to one
another by a guide bar that is oriented substantially
perpendicularly to the first and second support members in a rest
position of the first and second support members, which guide bar
is supported in or on a seat understructure and connected to the
first and second support members such that upon movement of one of
the first and second back supports in a first direction to the
front or to the rear of the stool or the chair the other one of the
first and second back supports is moved in a second direction
opposite to the first direction, respectively.
33. The backrest according to claim 32, wherein the guide bar has
ends that are pivotably connected to the first and second support
members, respectively, by a ball joint that is supported in an
elastically deformable sleeve.
34. The backrest according to claim 33, wherein the guide bar is
supported at a connecting point between the ends connected
pivotably to the first and second support members on the seat or a
seat understructure.
35. The backrest according to claim 34, wherein the guide bar is
supported by a ball joint at said connecting point between the
ends.
36. The backrest according to claim 32, wherein the guide bar is
guided in arc-shaped guide grooves provided in or on a seat
understructure, wherein imaginary axes of the arc-shaped guide
grooves extend parallel to the horizontal pivot axis of the first
and second support members and, relative to the front end of the
chair, are curved from the top to the rear and from the rear to the
bottom.
37. The backrest according to claim 33, wherein the guide bar is
connected pivotably to the second legs of the first and second
support members.
38. The backrest according to claim 37, wherein the second legs
each have an upwardly oriented projection and said projections are
supported by first springs that, in the rest position of the first
and second support members, are uniformly pressure-loaded.
39. The backrest according to claim 38, wherein the first springs
are coil springs whose longitudinal axis are perpendicular to the
horizontal pivot axis of the first and second support members and
are arranged in the area of the seat understructure.
40. The backrest according to claim 39, further comprising pressure
plates mounted on the projections and supported by plungers on
first springs.
41. The backrest according to claim 38, wherein the pretension of
the first springs is changeable.
42. The backrest according to claim 41, wherein the first springs
have ends opposite the pressure plates and said ends rest against
blocks movable in a longitudinal direction of the first springs,
wherein the blocks are supported on cams of a camshaft which
camshaft is turnable from the exterior.
43. The backrest according to claim 42, wherein said guide bar is
attached to a seat understructure supported by second springs such
that the seat understructure upon pivoting of the first and second
support members is movable to the front or to the rear relative to
a seat frame.
44. The backrest according to claim 32, wherein the back supports
are attached in a springy fashion on the carrier parts.
45. The backrest according to claim 32, wherein the back supports
are attached to the carrier parts so as to be pivotable about a
substantially vertically oriented axis, respectively.
46. The backrest according to claim 32, wherein the back supports
are positionable along the carrier parts at different height
positions.
47. The backrest according to claim 46, wherein the back supports
are attached to securing members that are slidable along the
carrier parts.
48. The backrest according to claim 47, wherein the securing
members each have a body attached thereto so as to be pivotable
against a first spring force about a horizontal axis, wherein said
bodies are attached to the back supports, respectively, so as to be
pivotable against a second spring force about a vertical axis.
49. The backrest according to claim 32, wherein the first and
second back supports are connected to one another by an elastically
deformable transverse stay and wherein a strength of the transverse
stay is selected such that the first and second back supports
function as individual supports and a movability of one of the
first and second back supports relative to the other one of the
first and second back supports maintained to a limited extent.
50. Chair furnished with a backrest according to claim 32.
51. Seating furniture comprising a seat, a support unit, and a
column, wherein the seat is attached with said support unit to the
column, and further comprising a backrest that has two back
supports that are arranged laterally adjacent to one another and
secured in a springy fashion, wherein the backrest further has a
first and a second substantially L-shaped support members each
comprised of a first leg and a second leg, wherein the first legs
form a substantially vertically extending carrier part,
respectively, and wherein the two back supports are attached to the
carrier parts and wherein the second legs are attached below the
seat so as to be pivotable against a spring force about a
horizontal pivot axis, wherein the support members each have a
separate spring element.
52. Seating furniture according to claim 51, wherein the force of
the spring elements acting on the support members is jointly
changeable.
53. Seating furniture according to claim 51, wherein the second
legs of the support members are configured as a two-arm lever,
wherein the spring force acts on a free lever end of the two-arm
lever.
54. Seating furniture according to claim 53, wherein the spring
force is effected by a spring element that is substantially
oriented vertically.
55. Seating furniture according to claim 53, wherein a free lever
end of the two-arm lever of the second leg has a bent section
oriented upwardly or downwardly, wherein an essentially
horizontally oriented spring element acts on the bent section.
56. Seating furniture according to claim 55, wherein the bent
section is oriented upwardly and wherein the spring element is a
tension spring and wherein ends of the tension springs of the
support members are attached to an adjusting member that is
securable relative to the horizontal pivot axis at different
spacings for changing the force acting on the support members.
57. Seating furniture according to claim 51, wherein the back
supports each are attached height-adjustably on the carrier parts,
respectively.
58. Seating furniture according to claim 51, wherein the back
supports each are attached in a springy fashion on the carrier
parts, respectively.
59. Seating furniture according to 58, wherein the back supports
each are pivotable relative to the carrier parts about a horizontal
axis, respectively.
60. Seating furniture according to claim 58, wherein the back
supports are pivotable about a vertical axis relative to the
carrier parts, respectively.
61. Seating furniture according to claim 58, wherein the back
supports are attached to securing members that are securable along
the carrier parts, respectively, at different height positions.
62. Seating furniture according to claim 61, wherein the back
supports each are attached by intermediate positioning of at least
on elastically deformable spring element on the securing members,
respectively.
63. Seating furniture according to claim 62, wherein the securing
members each have a body attached thereto so as to be pivotable
against a first spring force about a horizontal axis, wherein said
bodies are attached to the back supports, respectively, so as to be
pivotable against a second spring force about a vertical axis.
64. Seating furniture according to claim 51, wherein the support
members are fixedly securable at different spacings from one
another along the horizontal pivot axis.
Description
[0001] The invention concerns a backrest for a stool or chair with
two back supports that are positioned laterally adjacent to one
another and are supported in a springy fashion, wherein each one is
connected to a separate carrier part.
[0002] In such a backrest, disclosed in DE 90 06 316 U1, each back
support is provided on a separate carrier part. The carrier parts
are positioned relative to one another in a V-shape and the lower
ends of these carrier parts are attached to the rear of the seat on
the chair frame. Even though the back supports, as a result of the
springy properties of their two carrier parts, provide movability
to some degree in order to adjust to the different seated positions
of a seated person, it has been found that this construction is
unable to relieve the backbone of a seated person for extended
periods of time of being seated in changing seated positions as
well as of individual persons having greatly varying physical
build.
[0003] It is an object of the present invention to design a
backrest for a seat or a chair in such a way that the seated person
in different seated positions is supported optimally in the area of
the back or backbone.
[0004] As a solution to this object, it is provided according to
claim 1 that each carrier part forms the first leg of a
substantially L-shaped support member and that the second leg of
each support member is pivotable underneath the stool or chair seat
against a spring force about a horizontal axis. In this way, it is
ensured that each back support optimally follows the back movement
as a function of the different movements or seated positions of a
seated person without losing their support function.
[0005] In order to achieve that a seated person is optimally
supported even for a lateral movement or a lateral as well as
rearwardly oriented movement, according to further invention it is
provided that the support members are connected to one another by a
guide bar that is oriented in the rest position substantially
perpendicularly to the support members, wherein the guide bar is
supported in or on the seat understructure and connected to the
support member in such a way that upon displacement of one back
support to the front or to the rear the other back support is moved
in the opposite direction, respectively, wherein, for preventing a
"jump" between the two back supports, they are preferably connected
in a springy fashion to the support members in such a way that a
substantially uniform continuous backrest is present.
[0006] The guide bar is preferably pivotably connected with its
ends to the support members and, moreover, is pivotably supported
on the seat or seat understructure between its pivot points on the
support members.
[0007] Further preferred embodiments of the invention are disclosed
in the dependant claims.
[0008] The invention will be disclosed in the following with
reference to the attached drawings.
[0009] FIG. 1 shows a view of a backrest that is fastened to a post
of a chair or stool that is not shown otherwise.
[0010] FIG. 2 shows a view of a modified embodiment of a
backrest.
[0011] FIG. 3 shows a view of a further modified embodiment of a
backrest.
[0012] FIG. 4 shows an embodiment of the type of attachment of a
backrest on its carrier part.
[0013] FIG. 5 shows an exploded view of the embodiment according to
FIG. 4.
[0014] FIG. 6 shows an embodiment of the type of attachment of the
support member of the back support on the post of a chair or
stool.
[0015] FIG. 7 shows an isometric illustration of a chair.
[0016] FIG. 8 shows a detail in isometric illustration of the
column of the chair with attached seat frame on which the support
members for the back supports are pivotably attached.
[0017] FIG. 9 shows in isometric illustration a plan view onto the
seat understructure connected to the seat frame.
[0018] FIG. 10 shows for illustration of the inventive principle a
schematic partial view of the backrest construction in correlation
to the seat understructure.
[0019] FIG. 7 shows an isometric view of a chair, comprised of a
five star base 1.1 provided with coasters, a column 1 supported on
the five star base, a seat 100, and a backrest 3 with two back
supports 3.1 arranged laterally at a spacing from one another and
connected to L-shaped support members 4 that are each comprised of
a substantially vertically arranged carrier part 4.1 and a carrier
part 4.2 that is substantially horizontally arranged. Each back
support 3.1 is attached to a securing member 7 that is adjustable
along the correlated carrier part 4.1 so as to assume different
height-adjusted positions. Each securing member 7 comprises rubber
elements such that the individual back supports are movable
relative to the carrier part 4.1. The carrier parts 4.1 are
connected to one another by an elastically deformable transverse
stay 9 having a spring stiffness that is designed such that free
movability of the individual back support relative to the other
back support is maintained to a limited extent.
[0020] According to FIGS. 1 to 3, the carrier parts 4.2 are
pivotably supported by means of a support unit 2 about a horizontal
pivot axis 5. The carrier parts 4.2 of the support member 4 are
embodied as two-part levers, wherein a substantially vertically
oriented spring element 6 acts on the free lever end 4.3 of the
lever and wherein the force of the spring element acting on the
support member is changeable. This spring element 6 can be a
tension spring, a pneumatic or hydraulic spring element or the
like.
[0021] Catch openings 8 provided in the area of the carrier parts
4.1 make apparent that the securing members 7 are height-adjustably
mounted on the carrier parts 4.1. According to FIG. 2, the back
supports 3.1 are connected approximately at their center by an
elastically deformable transverse stay 3.2 whose strength is
designed such that the back supports 3.1 maintain their function as
individual supports wherein the free movability of one back support
relative to the other back support is maintained to a limited
extent.
[0022] According to FIG. 3 the two back supports 3.1 each are also
attached on their own carrier parts 4.1 of the support members 4 so
as to be springy individually. In this embodiment of the backrest
the securing members 7 are designed such that the upper ends of the
carrier parts 4.1 project upwardly past the securing member 7. The
free ends of the carrier parts 4.1 are connected to one another by
an elastically deformable transverse stay 9.
[0023] FIG. 6 shows a modified embodiment of the support member
that is pivotable about a horizontal axis. In or on the support
unit 2 a horizontal shaft 20 is provided that has opposite threads;
on it, the second legs 4.2 of the support member 4 are pivotably
supported. Each leg 4.2 is embodied as a two-arm lever whose free
lever end 4.4 is bent upwardly and has a substantially horizontally
oriented tension spring 22 attached thereto. For changing the force
acting on the support members, the tension springs 22 are attached
with their ends on an adjusting member 23 that is adjustable
relative to a horizontal axis at different spacings; it supports,
for example, a nut 24 that is engaged by a threaded pin 25 that is
turnable by means of a knurled wheel 26. Each leg 4.2 supports in
the area of its bearing location on the shaft 20 a threaded bushing
27 in such a way that upon rotation of the shaft 20 as a result of
the opposite threaded sections of this shaft the two legs 4.2 will
be adjusted relative to one another laterally so that the spacing
between the back supports 3.1 according to FIGS. 1 and 3 can be
adjusted.
[0024] FIGS. 8 and 9 show details of the seat frame 38 attached to
the upper end of the column 1 on which the two support members 4 in
the area of the free ends of the carrier parts 4.2 are attached so
as to be pivotable about the schematically illustrated pivot axis
39. On the seat frame 38 a substantially box-shaped seat
understructure 40 is fastened, for example, by screws 41 that are
guided in slotted holes 42 in such a way that the seat
understructure 40, relative to the seat frame 38, can be moved
forward and backward.
[0025] The inventive principle of this construction will be
explained in the following with the aid of the schematic
illustration of FIG. 9.
[0026] The principal idea of the teaching of the present invention
resides substantially in that the two back supports 3.1 are coupled
to one another such that upon change of the seated position of the
person seated on the chair (stool) a movement of one back support,
for example, to the rear causes a forced movement of the other back
support to the front. As a result of the springy suspension of the
back supports on the support members 4 the two back supports 3.1
are able to assume a position such that a substantially uniform
continuous backrest is provided when the user of the stool or chair
upon laterally reclining will rest more strongly or push more
strongly against one back support 3.1, in FIG. 9 the one to the
right, than against the other back support 3.1. The forced coupling
of the two back supports 3.1 to perform oppositely oriented
movements is effected by means of a guide bar 43 that, in the rest
position, is substantially perpendicularly oriented relative to the
support members 4; the guide bar is supported in or on the seat
understructure 40 and connected to the support parts 4.2 in such a
way that upon rearward movement of one back support 3.1 the other
back support is moved in the opposite direction, i.e., to the
front. In FIG. 9 the deflection angle of the guide bar 43 relative
to the central position is illustrated in an exaggerated way for
explaining the action principle. In reality, the deflection angle
is only minimal so that upon pivoting the ends of the guide bar 43
carry out only very minimal movements that are in the range of
tenth of millimeters and, in this way, are compensated by the
tolerances of the construction.
[0027] The ends of the guide bar 43 are connected to the respective
carrier parts 4.2, for example, by means of ball joints 44
schematically illustrated in FIG. 8b which are preferably supported
in elastically deformable sleeves 44.1. The guide bar 43 is also
preferably pivotably supported by means of ball joints 45
illustrated in FIG. 9a in or on the longitudinal support 40.2 of
the seat understructure 50 in the central area between its
connecting points on the carrier parts 4.2.
[0028] The carrier parts 4.2 are supported by means of coil springs
46 arranged on the seat understructure 40 such that the two back
supports 3.1 in the unloaded rest position have the same spacing
from the seat understructure 40 and the guide bar 43 is in a rest
or middle position.
[0029] According to FIG. 8, the carrier parts 4.2 have upwardly
oriented projections 47 on which the guide bar 43 is connected
pivotably. Pressure plates 48 adjoin the projections 47 that by
means of plungers 49 passing through the frame 40.1 of the
box-shaped seat understructure 40 are supported on the coil springs
46 that are arranged perpendicularly to the pivot axis 39 in the
seat understructure 40. The coil springs 46 are supported on blocks
50 that are slidable in the longitudinal direction of the springs
and, in turn, are seated on cams 52 of a camshaft 51 that is
turnable by means of a handle 53 in order to change by rotation of
the cams 52 the pretension of the springs 46.
[0030] The guide bar 43 is guided in the frame 40.1 of the seat
understructure 40 in an arc-shaped guide groove 54 whose imaginary
axes are parallel to the pivot axis 39 of the support members 4 and
relative to the front of the chair are curved from top toward the
bottom and toward the rear.
[0031] The guide groove 54 enables a pivoting or a tilting movement
of the guide bar 43 in the area of the ball joints 45 in such a way
that, when pivoting of the carrier part 4.2 to the rear, this
carrier part is also pivoted downwardly while at the same time the
opposite support part 4.2 is pivoted with opposite movements.
[0032] FIG. 8 shows a position of the two carrier parts 4.2 in a
central position in which they are substantially parallel to one
another when the two back supports 3.1 are either not loaded or
uniformly loaded.
[0033] When a user with uniform loading of both back supports 3.1
reclines backwardly, the guide bar 43 follows this rearward
movement so that as a result of the pivotable support action of the
guide bar 43 in or on the longitudinal support 40.2 the entire seat
understructure 40 is pulled, on the one hand, to the rear and, on
the other hand, its rear area is pivoted downward or lowered
simultaneously; this is done in accordance with a partial seat
support action disclosed in DE 299 08 599 U1 with synchronizing
mechanism and, as this structure is known, is not the object of the
present invention.
[0034] Such a synchronizing mechanism serves for pivoting the seat
in accordance with a predetermined angle ratio when pivoting the
backrest to the front or to the rear.
[0035] The rearwardly oriented movement of the seat understructure
40 is realized against the force of pressure springs 60 that are
supported between a support plate 61 that is stationary and forms
part of the seat frame 38 and a support surface that is part of the
movable seat understructure 40.
[0036] The FIGS. 4 and 5 show how the securing member 7 is attached
to a back support in order to enable pivot movements of this back
support 3.1 relative to the securing member 7 about a vertical axis
as well as a horizontal axis. A main body 10 that is box-shaped and
open in the upward and downward direction is provided at the end
facing the securing member 7 with two wall sections 10.1 that are
positioned at a spacing to one another and are preferably
triangular in shape; they have opposed bearing openings 10.11. On
the securing member 7 a horizontally oriented bearing bushing 11 is
mounted so that after passing the axle pin 12 through the bearing
bushings 11 aligned with the bearing openings 10.11 the main body
10 is pivotably connected to the securing member 7. According to
FIG. 5, in the space between the main body 10 and the securing
member 7 a rubber stop 14 is positioned that is provided with a
recess 14.1 that is matched to the shape of the bearing bushing 11.
The spring stiffness of the rubber stop is designed such that a
controlled pivot movement of the main body 10 about the horizontal
axis 2 that is defined by the axle pin 12 is possible.
[0037] The main body 10 is provided on the side facing away from
the securing member 7 with an opening that is delimited upwardly
and downwardly by wall sections 10.2. The wall sections 10.2 are
provided with bearing openings 10.21. A fastening element 13 that
can be screwed fixedly to the back of each back support 3.1 has a
vertically oriented bearing bushing 13.1 that supports a radially
outwardly projecting partition 13.2. When the bearing bushing 13.1
is aligned with the bearing openings 10.21, an axle pin 14.2 can be
passed through these bearing openings 10.21 and the bearing bushing
13.1 so that the main body 10 is attached so as to be pivotable
about a vertical axis on the fastening element 13. The partition
13.2 limits within the sleeve-shaped main body 10 two receiving
spaces for spring elements 15, preferably cylindrical rubber stops,
whose dimensions and spring stiffness are selected such that a
limited relative movement between the fastening element 13 and the
main body 10 about a defined vertical axis defined by the axle pin
11 is provided.
* * * * *