U.S. patent application number 13/006830 was filed with the patent office on 2011-07-28 for support structure for a back part and/or a seat of a seat assembly and seat assembly comprising such a support structure.
This patent application is currently assigned to Stoll Giroflex AG. Invention is credited to Wolfgang Emmenegger, Stephan Pfeifer.
Application Number | 20110181086 13/006830 |
Document ID | / |
Family ID | 42104388 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110181086 |
Kind Code |
A1 |
Pfeifer; Stephan ; et
al. |
July 28, 2011 |
SUPPORT STRUCTURE FOR A BACK PART AND/OR A SEAT OF A SEAT ASSEMBLY
AND SEAT ASSEMBLY COMPRISING SUCH A SUPPORT STRUCTURE
Abstract
A support structure for a back part and/or a seat of a seat
assembly includes a base support, a support part, and a power
system. The support part is arranged on the base support to support
and/or hold the respective back part and/or seat, and is attached
to the base support to allow movement of the support part relative
to the base support. The power system, which includes first and
second spring elements and a coupling device, generates a reset
force in response to (and directed opposite to) the respective
movement of the support part. When the coupling device is in a
first state, the second spring element generates a second reset
force directed opposite to the movement of the support part. When
the coupling device is in the second state, the second spring
element does not generate the second reset force.
Inventors: |
Pfeifer; Stephan; (Koblenz,
CH) ; Emmenegger; Wolfgang; (Kussaberg-Dangstetten,
DE) |
Assignee: |
Stoll Giroflex AG
Koblenz
CH
|
Family ID: |
42104388 |
Appl. No.: |
13/006830 |
Filed: |
January 14, 2011 |
Current U.S.
Class: |
297/300.1 |
Current CPC
Class: |
A47C 1/03266 20130101;
A47C 1/03288 20130101; A47C 1/03277 20130101; A47C 1/03255
20130101 |
Class at
Publication: |
297/300.1 |
International
Class: |
A47C 1/024 20060101
A47C001/024 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 2010 |
EP |
EP 10405014.1 |
Claims
1. A support structure for a back part and/or a seat of a seat
assembly, comprising: a base support; a support part arranged on
the base support and configured to support and/or hold the
respective back part and/or the respective seat, said support part
being attached to the base support to allow relative movement of
the support part relative to the base support; a power system
configured to generate a reset force in response to the respective
movement of the support part, wherein the reset force is directed
opposite to the movement, wherein the power system comprises a
first spring element coupled to the base support and to the support
part, wherein, in response to the respective movement of the
support part, the first spring element is configured to generate a
first reset force directed opposite to the respective movement of
the support part; a second spring element; and a coupling device
configured to couple the respective second spring element to the
base support and/or to the support part, wherein the coupling
device is configured to be brought either into the first or into a
second state, wherein, in the event that the coupling device is in
the first state, the respective second spring element is coupled to
the base support and to the support part, whereby, in response to
the respective movement of the support part, the respective second
spring element generates a second reset force directed opposite to
the respective movement of the support part, and wherein, in the
event that the coupling device is in the second state, the
respective second spring element is not coupled to the base support
and/or to the support part, whereby the respective second spring
element does not generate a second reset force directed opposite to
the respective movement of the support part.
2. The support structure according to claim 1, further comprising a
control device configured to adjust the respective state of the
respective coupling device, whereby the respective coupling device
is brought either into the first or into the second state.
3. The support structure according to claim 1, further comprising a
plurality of the second spring elements and a plurality of the
coupling devices, wherein the plurality of coupling devices are
configured to be brought into the first or into the second state
independent from one another.
4. The support structure according to claim 3, wherein all of the
plurality of coupling devices are in the second state so that none
of the second spring elements are coupled to the base support and
to the support part.
5. The support structure according to claim 3, wherein one of the
plurality of coupling devices is in the second state so that a
corresponding one of the second spring elements is coupled to the
base support and to the support part.
6. The support structure according to claim 3, wherein at least two
of the plurality of coupling devices are in the second state so
that at least two of the second spring elements are coupled to the
base support and to the support part.
7. The support structure according to claim 1, wherein the second
spring element comprises a first section and a second section
configured to be moved relative to one another to generate the
respective reset force, and wherein the coupling device comprises:
first holding means for holding the first section of the respective
second spring element, said first holding means connected to the
base support and configured to interact with the first section of
the respective second spring element, whereby, when the coupling
device is brought into the first state, the first section of the
respective second spring element is held in a predetermined
position relative to the base support; and second holding means for
holding the second section of the respective second spring element,
said second holding means connected to the support part and
configured to interact with the second section of the respective
second spring element, whereby, when the coupling device is brought
into the first state, the second section of the respective second
spring element is held in a predetermined position relative to the
support part.
8. The support structure according to claim 7, wherein, when the
coupling device is brought into the second state, the first holding
means is detached from the first section of the respective second
spring element in response to the respective movement of the
support part.
9. The support structure according to claim 8, wherein the first
holding means is moveable between at least two different positions,
wherein, in one of the positions, the first holding means is in
contact with the first section of the respective second spring
element such that the first section is held in the predetermined
position relative to the base support, and, in the other one of the
positions, the first holding means is separated from the first
section of the respective second spring element.
10. The support structure according to claim 9, further comprising
actuating means for moving the respective first holding means from
one of the positions into the other one of the positions.
11. The support structure according to claim 10, wherein the
actuating means comprises a rotatable cam shaft including at least
one cam assigned to the respective first holding means, wherein the
respective first holding means are moveable by the respective
assigned cam in response to a rotation of the cam shaft.
12. The support structure according to claim 7, wherein, when the
coupling device is brought into the second state, the second
holding means is detached from the second section of the respective
second spring element in response to the respective movement of the
support part.
13. The support structure according to claim 12, wherein the second
holding means is movable between at least two different positions,
wherein, in one of the positions, the second holding means is in
contact with the second section of the respective second spring
element such that the second section is held in the predetermined
position relative to the support part, and, in the other one of the
positions, the second holding means is separated from the second
section of the respective second spring element.
14. The support structure according to claim 1, wherein the
respective first spring element comprises an elastomer torsion
spring element including an inner housing, an outer housing
surrounding the inner housing, and an elastomer body arranged in a
space between the inner housing and the outer housing, wherein said
inner housing comprises at least one contact surface in contact
with, and fixedly connected to, the elastomer body, wherein said
outer housing comprises at least one contact surface in contact
with, and fixedly connected to, the elastomer body, wherein at
least one of the inner housing and the outer housing is arranged so
as to be rotatable relative to the other about an axis of rotation,
wherein the elastomer torsion spring element is coupled to the base
support and to the support part such that respective movement of
the support part causes a rotation of the inner housing and/or of
the outer housing about the axis of rotation, whereby relative
rotation between the inner housing and the outer housing generates
a deformation of the elastomer body, which deformation generates a
reset torque between the inner and outer housings, said reset
torque being directed opposite to the rotation.
15. The support structure according to claim 14, wherein the
support part is attached to a bearing shaft supported on the base
support, whereby the support part is pivotable about a pivot axis,
wherein one of the inner and outer housings is rigidly connected to
the base support, and wherein the other of the inner and outer
housings is rigidly connected to the support part or to the bearing
shaft.
16. The support structure according to claim 14, wherein the
contact surface of at least one of the inner and outer housings
comprises a non-circular cross section in a sectional plane
perpendicular to the axis of rotation.
17. The support structure according to claim 14, further comprising
a holding element arranged on the respective elastomer torsion
spring element, wherein the holding element is configured to hold
the inner housing of the elastomer torsion spring element in a
predetermined basic position relative to the outer housing of the
elastomer torsion spring element, wherein the elastomer body
comprises a predetermined elastic deformation in said basic
position and generates a reset torque between the outer housing and
the inner housing having a predetermined minimum value, and wherein
the holding element is configured to release a rotation of the
inner housing relative to the outer housing about an angle of
rotation about the axis of rotation in a direction of rotation, the
reset torque increasing as the angle of rotation increases.
18. The support structure according to claim 17, wherein the
holding element includes at least one clamping element comprising a
first section fixedly engaged with one of the inner and outer
housings; and a second section striking against a section of the
other of the inner and outer housings when the inner housing is in
the predetermined basic position relative to the outer housing,
wherein the clamping element allows relative rotation between the
inner and outer housings about the axis of rotation in the
direction of rotation, whereby the reset torque increases.
19. The support structure according to claim 18, wherein the inner
housing comprises a recess and the first section of the clamping
element is inserted into the recess in the inner housing in a
torsionally rigid manner, and wherein, when the inner housing is in
the predetermined basic position relative to the outer housing, the
second section of the clamping element strikes against a section of
the outer housing.
20. The support structure according to claim 1, wherein the
respective second spring element is an elastomer torsion spring
element including an inner housing, an outer housing surrounding
the inner housing, and an elastomer body arranged in a space
between the inner housing and the outer housing, wherein said inner
housing comprises at least one contact surface in contact with, and
fixedly connected to, the elastomer body, wherein said outer
housing comprises at least one contact surface in contact with, and
fixedly connected to, the elastomer body, wherein at least one of
the inner housing and the outer housing is arranged so as to be
rotatable relative to the other about an axis of rotation, wherein,
when the coupling device is brought into the first state, the
elastomer torsion spring element is coupled to the base support and
to the support part such that respective movement of the support
part causes a rotation of the inner housing and/or of the outer
housing about the axis of rotation, whereby relative rotation
between the inner housing and the outer housing generates a
deformation of the elastomer body, which deformation generates a
reset torque between the inner and outer housings, said reset
torque being directed opposite to the rotation.
21. The support structure according to claim 20, wherein the
support part is attached to a bearing shaft supported on the base
support, whereby the support part is pivotable about a pivot axis,
and wherein, when the coupling device is brought into the first
state, one of the inner and outer housings is rigidly connected to
the base support, and the other of the inner and outer housings is
rigidly connected to the support part or to the bearing shaft.
22. The support structure according to claim 20, wherein the
contact surface of at least one of the inner and outer housings
comprises a non-circular cross section in a sectional plane
perpendicular to the axis of rotation.
23. The support structure according to claim 20, further comprising
a holding element arranged on the respective elastomer torsion
spring element, wherein the holding element is configured to hold
the inner housing of the elastomer torsion spring element in a
predetermined basic position relative to the outer housing of the
elastomer torsion spring element, wherein the elastomer body
comprises a predetermined elastic deformation in said basic
position and generates a reset torque between the outer housing and
the inner housing having a predetermined minimum value, and wherein
the holding element is configured to release a rotation of the
inner housing relative to the outer housing about an angle of
rotation about the axis of rotation in a direction of rotation, the
reset torque increasing as the angle of rotation increases.
24. The support structure according to claim 23, wherein the
holding element includes at least one clamping element comprising a
first section fixedly engaged with one of the inner and outer
housings; and a second section striking against a section of the
other of the inner and outer housings when the inner housing is in
the predetermined basic position relative to the outer housing,
wherein the clamping element allows relative rotation between the
inner and outer housings about the axis of rotation in the
direction of rotation, whereby the reset torque increases.
25. The support structure according to claim 24, wherein the inner
housing comprises a recess and the first section of the clamping
element is inserted into the recess in the inner housing in a
torsionally rigid manner, and wherein, when the inner housing is in
the predetermined basic position relative to the outer housing, the
second section of the clamping element strikes against a section of
the outer housing.
26. A seat assembly, comprising: a seat; a back part; and a support
structure according to claim 1, wherein the support part supports
at least one of the back part and the seat.
27. A seat assembly, comprising: a seat; a back part; and a support
structure according to claim 1, wherein the support part holds at
least one of the back part and the seat in a position, wherein the
position is a function of a position of the support part relative
to the base support.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of European
Patent Application No. EP 10405014, filed on Jan. 22, 2010, the
entirety of which is hereby incorporated by reference.
BACKGROUND
[0002] 1. Field of Invention
[0003] The invention relates to a support structure for a back part
and/or a seat of a seat assembly and to a seat assembly comprising
such a support structure.
[0004] 2. Related Art
[0005] For the most part, seat assemblies, for example chairs, have
a modular structure: in addition to a seat and a back part, if
necessary, which can comprise a backrest, for example, they
normally also comprise a support structure for the respective back
part and/or the respective seat, wherein it is the object of the
support structure to hold the seat and the back part, if necessary,
in a certain position and to accommodate a load, which can be
transferred onto the seat or the back part, respectively, by a
person sitting on the seat assembly, for example, and to hold the
seat and the back part, if necessary, in a stable position in each
case in response to the impact of the respective load.
[0006] Oftentimes, seat assemblies are not embodied so as to be
rigid. Oftentimes, the respective support structure is constructed
such that even though the support structure can be positioned in
the room in a stationary manner, the spatial position of the
respective back part and/or of the respective seat can be changed
relative to the support structure. This provides for the
possibility, for example, that the spatial arrangement of the back
part and/or of the seat can be adapted to the respective posture of
a person, who sits on the respective seat assembly and who
constantly changes his posture, on the one hand, or to achieve, for
example, that the same seat assembly can be adjusted to different
requirements of different persons, who can differ with regard to
their height or weight or with regard to their preferred posture
when sitting. For this purpose, a conventional support structure of
a seat assembly usually comprises a base support, which can be
positioned in a stationary manner in the room, and at least one
support part, which is arranged on the base support and which is
attached to the base support such that a movement of the support
part can be carried out relative to the base support. The purpose
of said support part is to hold the back part and/or the seat in a
position, which is a function of the relative position of the
support part with respect to the base support. The back part or the
seat, respectively, must thereby not be attached directly to the
support part: the back part or the seat, respectively, can in each
case be connected to said support part or can be coupled to the
support part via one or a plurality of other components.
[0007] A support structure of the afore-mentioned type can also be
equipped with a power system for generating at least one reset
force, which is generated in response to the respective movement of
the support part and which is directed opposite to this movement.
For example, such a power system can comprise one or a plurality of
spring elements, which are in each case coupled to the base support
and the support part such that the spring element generates a reset
force, which is directed opposite to the respective movement of the
support part in response to the respective movement. Such a power
system ensures a flexible arrangement of the back part or of the
seat, respectively, such that the respective back part and/or the
respective seat are deflected out of a predetermined position of
equilibrium, if necessary, in response to the impact of a force,
wherein the support part is at the same time deflected out of a
predetermined position of equilibrium and a reset force, which
counteracts the deflection of the support part, is generated. As a
rule, the respective reset force is thereby greater, the further
the support part is deflected out of the original position of
equilibrium. Due to the fact that the power system generates a
reset force, which is directed opposite to the respective movement
of the support part, the support part can subsequently assume a new
position of equilibrium as soon as all of the forces acting on the
support part compensate one another. In so doing, the back part or
the seat, respectively, can in each case be held in a position of
equilibrium, which is a function of the respective stress of the
back part or of the seat, respectively. The latter ensures a high
seating comfort, the more so as the rear part and/or the seat can
in each case be adapted to the current posture of a person sitting
on the seat assembly and the respective reset force created by the
power system in each case acts as a support for the person, who is
sitting down.
[0008] To even further improve the seating comfort, which is
ensured by a power system of the afore-mentioned type, such a power
system can be designed such that the size of the reset force, which
the power system generates in response to a certain deflection of
the support part out of a predetermined position of equilibrium,
can be varied to a certain extent and can be adjusted, as needed.
The latter allows for the power system to be adapted to different
requirements. As a rule, an adjustment of the power system in which
the power system generates a relatively large reset force in
response to a predetermined deflection of the support part ("hard"
adjustment of the power system), is appropriate in the case of tall
or heavy persons, respectively, for example, while in the case of
short or light persons, respectively, an adjustment of the power
system in which the power system generates a relatively small reset
force in response to a predetermined deflection ("soft" adjustment
of the power system) would be more suitable.
[0009] A seat assembly, which comprises a changeable power system
of the afore-mentioned type, is known from EP 1486142 A1. This seat
assembly, a chair, encompasses a support structure in combination
with a power system of the afore-mentioned type. In this case, the
power system comprises an elastomer torsion spring element, which
serves the purpose of generating a reset torque, which counteracts
a pivoting motion of a support for a seat (referred to hereinbelow
as "seat support", if applicable) about an axis of rotation. The
elastomer torsion spring element includes an inner housing and an
outer housing, wherein an elastomer body is integrated in a space
between the inner housing and the outer housing. On its outer side,
the inner housing encompasses a contact surface, on which the
elastomer body is in contact with the inner housing and on its
inner side, the outer housing encompasses contact surface, on which
the elastomer body is in contact with the outer housing. The
elastomer body is thereby fixedly connected to the respective
contact surface of the inner housing and of the respective contact
surface of the outer housing, so that the elastomer body can
neither slip on the contact surface of the inner housing nor on the
contact surface of the outer housing relative to the inner housing
or to the outer housing. In the instant case, the outer housing and
the inner housing are embodied in a cylindrical manner and are
oriented coaxially to one another. The outer housing is held on a
support structure of the chair, while the inner housing sits on a
shaft in a torque proof manner, with said shaft being capable of
rotating about its longitudinal axis. A seat of the chair is
coupled to the shaft such that the shaft is rotated about its
longitudinal axis and the seat is pivoted out of a predetermined
basic position in the event that the seat is loaded by the weight
of a person. Due to the rotation of the shaft, the inner housing is
rotated about its longitudinal direction and is thereby twisted
relative to the outer housing with the effect that the elastomer
torsion spring element generates a reset torque, which acts on the
shaft or on the seat, respectively, and which counteracts the
rotation of the shaft or the pivoting motion of the seat,
respectively, and which increases as the angle of rotation
increases. In the case of the torsion spring element, the size of
the minimal torque acting on the shaft when the seat is pivoted out
of the mentioned basic position (referred to hereinbelow as
"minimum reset torque") can be changed. For this purpose, the outer
housing can be rotated about its longitudinal axis by means of a
rotating mechanism, which is arranged on the support structure of
the chair, and can thus be rotated about the longitudinal axis of
the shaft, wherein the outer housing is twisted relative to the
support structure of the chair and relative to the inner housing or
to the shaft, respectively. The elastomer torsion spring element is
prestressed by means of the twisting of the outer housing relative
to the inner housing, wherein the angle or rotation, about which
the outer housing is twisted relative to the inner housing when the
seat is located in the basic position, determines the size of the
"minimum reset torque".
[0010] The power system of the afore-mentioned seat assembly has
different disadvantages. The mentioned elastomer torsion spring
element has the disadvantage that the reset torque, which is
generated in response to a rotation of the mentioned shaft about a
certain angle of rotation, shows a relatively low increase as
function of the respective angle of rotation, in particular when
the elastomer torsion spring element is not or only slightly
prestressed. According thereto, the outer housing of the elastomer
torsion spring element must be twisted about a relatively large
angle of rotation relative to the inner housing and the elastomer
body of the elastomer torsion spring element must be prestressed to
a relatively large extent when a large minimum reset torque is to
be adjusted, so as to be able to provide an adequate seating
comfort to persons with a heavy weight, e.g. In response to the
twisting of the outer housing of the elastomer torsion spring
element relative to the inner housing, a relatively large force
must be applied when the elastomer body is to be prestressed to a
large extent so as to achieve the highest possible reset torque. It
is thus time-consuming and laborious to vary the minimum reset
torque by manually twisting the outer housing relative to the inner
housing across a large area. The reset torque generated by the
elastomer torsion spring element further increases in a highly
non-linear manner (progressively) as a function of the angle of
rotation of the shaft when the shaft is to be rotated about an
angle of rotation in the range of from 0 to approx. 70.degree., for
example. In the area of the upper end of the mentioned area of the
angle of rotation, the elastomer body is already prestressed to
such an extent that damages to the elastomer body must be expected
in response to a further increase of the angle of rotation. The
minimum reset torque of the elastomer torsion spring element can
thus only be increased up to a certain upper limit. The resilience
of the power system is thus limited.
SUMMARY
[0011] It is an object to avoid the abovementioned disadvantages
and to create a support structure or a seat assembly, respectively,
comprising a power system, which makes it possible to be able to
change the reset force, which is in each case generated by the
power system, across the largest possible range in a simple and
comfortable manner, so that the power system can be adapted to the
requirements of different persons with large differences with
regard to their weight in a simple and comfortable manner.
[0012] This and other objects are solved by means of a support
structure for a back part and/or a seat of a seat assembly, and by
means of a seat assembly including such a support structure.
[0013] According to an embodiment of the invention, the support
structure comprises a base support, at least one support part,
which is arranged on the base support, for supporting and/or
holding the respective back part and/or the respective seat, with
said support part being attached to the base support such that a
movement of the support part relative to the base support can be
carried out, and a power system for generating at least one reset
force, which is generated in response to the respective movement of
the support part and which is directed opposite to this movement.
The power system thereby comprises at least a first spring element,
which is coupled to the base support and to the support part such
that, in response to the respective movement of the support part,
the first spring element generates a first reset force, which is
directed opposite to the movement of the support part.
[0014] The support part is thereby embodied to hold the respective
back part and/or the respective seat of the respective seat
assembly in a position, which is a function of the relative
position of the support part with reference to the base support.
The back part or the seat, respectively, must thereby not be
attached directly to the support part: the back part or the seat,
respectively, can in each case be connected to the mentioned
support part or coupled to the support part via one or a plurality
of other components.
[0015] According to an embodiment of the invention, the power
system additionally comprises at least a second spring element and
at least one coupling device for coupling the respective second
spring element to the base support and/or to the support part, with
said coupling device being capable of being brought either into a
first or into a second state, wherein [0016] in the event that the
coupling device is brought into the first state, the respective
second spring element is coupled to the base support and to the
support part such that the respective second spring element, in
response to the respective movement of the support part, generates
a second reset force, which is directed opposite to the respective
movement of the support part and [0017] in the event that the
coupling device is brought into the second state, the respective
second spring element is not coupled to the base support and/or to
the support part, so that the respective second spring element does
not generate a reset force, which is directed opposite to the
respective movement.
[0018] Accordingly, the power system of the support structure
according to an embodiment of the invention comprises different
groups of spring elements comprising different functions: one or a
plurality of "first" spring elements and one or a plurality of
"second" spring elements.
[0019] The respective first spring element is thereby in each case
coupled to the base support and to the support part and generates a
("first") reset force, which in each case acts on the support part,
when the support part is moved relative to the base support. In the
event that the power system comprises a plurality of first spring
elements of this type, the totality of all of the first spring
elements generates a reset force, which acts on the support part
and which corresponds to the sum of the reset forces, which are
generated by the respective first spring elements.
[0020] However, the respective second spring element can either be
coupled to the base support as well as to the support part--as a
function on the respective state of the coupling device--or (in
each case as a function of the respective realization of the
coupling device) it can be decoupled at least from the base support
or at least from the support part or from the base support as well
as from the support part. The respective second spring element only
generates a ("second") reset force, which acts on the support
part--in addition to the reset force, which is generated by the
respective first spring elements--when the support part is moved
relative to the base support when the coupling device is in a
state, in which the respective second spring element is coupled to
the base support as well as to the support part. In the other state
of the coupling device, the respective second spring element cannot
generate a reset force, which acts on the support part--due to the
decoupling from the base support and/or from the support part.
[0021] In the event that the power system comprises a plurality of
second spring elements of this type, the totality of all second
spring elements generates a reset force, which acts on the support
part and which corresponds to the sum of all reset forces being
generated by those second spring elements, which are currently
coupled to the base support as well as to the support part by means
of the respective coupling devices.
[0022] Accordingly, a reset force, which corresponds to the sum of
all of the ("first" and "second") reset forces generated by the
respective first and second spring elements, acts on the support
part in each case.
[0023] According to an embodiment of the invention, the reset force
acting on the support part can be changed by changing the state of
the respective coupling device, wherein the number of those second
spring elements, which are currently coupled to the base support as
well as to the support part, is changed in each case.
[0024] The reset force acting on the support part (in response to a
predetermined deflection of the support part out of a basic
position), can thereby be varied in a range, the size of which is
substantially a function of the number of the respective second
spring elements and of the respective characteristics of the
respective second spring elements. Due to the fact that the number
of the respective second spring elements can on principle be chosen
randomly, the invention allows for the variation of the reset
force, which acts on the support part, in any range, by means of
suitably selecting the number of the second spring elements and by
suitably selecting the characteristics of the respective spring
elements. The characteristics of the respective spring elements can
thereby be chosen such that none of the spring elements can be
overloaded. The support structure according to an embodiment of the
invention can thus in each case be designed such that the support
structure can be adapted to the requirements of different persons
having large differences with regard to their weight. In the event
that the support structure is to be adjusted to a person having a
relatively small weight, the respective coupling devices can in
each case be brought into a state, for example, in which none of
the respective second spring elements is coupled to the base
support as well as to the support part. In this case, only the
respective first spring elements contribute to the reset force,
which acts on the support part. In the event, however, that the
support structure is to be adjusted to a person having a relatively
large weight, the respective coupling devices can be brought into a
state, for example, in which the respective second spring elements
are coupled to the base support as well as to the support part. In
this case, all of the first and second spring elements contribute
to the reset force, which acts on the support part.
[0025] Advantageously, there are no limitations with reference to
the selection of the respective spring elements: on principle, any
type of spring elements can be used to realize the support
structure according to the invention, e.g. spring elements, which
comprise an elastically deformable body, or pneumatic or hydraulic
spring elements, or spring elements, which can be loaded by means
of a torsion or a pressure or a tension, or other spring
elements.
[0026] The respective coupling device can be realized in many ways,
for example with mechanical means, electromechanical, magnetic,
pneumatic, hydraulic or other means.
[0027] Advantageously, the coupling device can be realized such
that movements, which must be carried out opposite to a force,
which is generated by the respective second spring element, are not
necessary in response to the coupling of the respective second
spring element to the base support or to the support part,
respectively, or in response to the decoupling of the respective
second spring element from the base support or from the support
part, respectively. As a rule, the respective coupling device can
thus be brought from one of the respective states into a different
state quickly, with a small expenditure of force and thus
comfortably for a user.
[0028] An embodiment of the support structure according to the
invention comprises a control device for impacting the respective
state of the respective coupling device such that the respective
coupling device can either be brought into the first or the second
state. Such a control device makes it possible for a user to
comfortably bring the coupling device into the different states,
without having to touch the coupling device or the respective
spring element, which is to be coupled to the base support or the
support part, respectively, by means of the coupling device. This
is so because, as a rule, the coupling device or the respective
spring element is not easily accessible to a user. The control
device makes it possible for a user to control the respective
coupling device in a simple and comfortable manner, for example
when sitting on the respective seat assembly. Such a control device
is advantageous, in particular, when a plurality of coupling
devices are available and must be controlled independent on one
another. Such a control device can be realized in many different
ways, for example by means of mechanical, electromechanical,
electrical, pneumatic, hydraulic or other means (in each case
depending on the construction and the function of the respective
coupling devices).
[0029] An embodiment of the support structure according to the
invention comprises a plurality of second spring elements and a
plurality of coupling devices, wherein two different coupling
devices can in each case be brought into the first or the second
state independent on one another. In this case, a plurality of
second spring elements can be coupled to the base support or to the
support part, respectively, independent on one another and can be
decoupled from the base support and/or from the support part. In an
alternative of this embodiment, the support structure can be
embodied such that the respective second spring elements a) can in
each case be brought into a state, in which none of the second
spring elements is coupled to the base support and to the support
part or b) can in each case be brought into a state, in which one
of the second spring elements is coupled to the base support and to
the support part, or c) can in each case be brought into a state,
in which a plurality of the second spring elements are coupled to
the base support and to the support part. Based on a state, in
which none of the second spring elements is coupled to the base
support as well as to the support part, this embodiments makes it
possible to successively increase the number of the second spring
elements, which are coupled to the base support and to the support
part, by impacting the respective coupling device and to thus
increase the reset force, which can be generated by means of the
power system, step by step in a plurality of steps. This embodiment
has the advantage that the power system can be adapted to the
respective weight of different persons in a particularly fine and
accurate manner, namely for a range of weights, which is greater,
the greater the number of the second spring elements.
[0030] As a rule, the respective spring elements are constructed
such that the generation of a reset force is connected to a change
of the extension of the respective spring element in at least one
direction.
[0031] An embodiment of the support structure is accordingly
characterized in that the respective second spring element
encompasses a first section and a second section, with said
sections being capable of being moved relative to one another for
generating the respective reset force. The coupling device further
comprises: [0032] (i) a first holding means for holding the first
section of the respective second spring element, with said first
holding means being connected to the base support and being
embodied to interact with the first section of the respective
second spring element such that this first section of the
respective second spring element is held in a predetermined
position relative to the base support, in the event that the
coupling device is brought into the first state and [0033] (ii) a
second holding means for holding the second section of the
respective second spring element, with said second holding means
being connected to the support part and being embodied to interact
with the second section of the respective second spring element
such that this second section of the respective second spring
element is held in a predetermined position relative to the support
part in the event that the coupling device is brought into the
first state.
[0034] This embodiment has the advantage that the coupling device
can be realized with simple means (based on holding means). A
movement of the support part relative to the base support in each
case acts on that second spring element, the first section of which
is held by the first holding means and the second section of which
is held by the second holding means, such that the first section of
this second spring element is moved in response to a movement of
the support part relative to the second section of the second
spring element, so that the second spring element inevitably
generates a reset force, which acts on the support part.
[0035] An advantageous alternative of the aforementioned embodiment
is designed such that the first holding means of the respective
coupling device is embodied to hold the first section of the
respective second spring element so as to be capable of being
detached and--in the event that the coupling device is brought into
the second state--is brought into a state, in which the first
section of the respective second spring element is detached from
the respective first holding means in response to the respective
movement of the support part, and/or that the second holding means
of the respective coupling device is embodied for holding the
second section of the respective second spring element so as to be
capable of being detached and--in the event that the coupling
device is brought into the second state--is brought into a state,
in which the second section of the respective second spring element
is detached from the respective second holding means in response to
the respective movement of the support part. To achieve that the
respective second spring element is not coupled to the base support
and to the support part and to accordingly not generate a reset
force, the coupling device must be equipped such that the second
spring element is detached from the first holding means and/or from
the second holding means. It is thus not necessary for the first
holding means as well as the second holding means to be embodied as
means for detachably holding, so as to provide for a decoupling of
the second spring element from the base support or from the support
part, respectively. When the second holding means is designed such,
for example, that it can hold the second section of the second
spring element so as to be capable of being detached, the first
holding means can then also be embodied such that it establishes a
fixed, rigid connection, if necessary, between the second section
of the second spring element and the base support.
[0036] If, on the other hand, the first holding means is designed
such that it can hold the first section of the second spring
element so as to be capable of being detached, the second holding
means can then also be embodied such that it established a fixed,
rigid connection, if necessary, between the first second of the
second spring element and the support part.
[0037] In a further development of the afore-mentioned embodiment
of the support structure, the first holding means can be a movable
part, for example, which can be brought into at least two different
positions, wherein the first holding means, in one of these
positions, is in contact with the first section of the respective
second spring element such that this first section is held in the
predetermined position relative to the base support, and is
separated from the first section of the respective second spring
element in the other one of these positions. Accordingly, the
second holding means can be a movable part, which can be brought
into at least two different positions, wherein the second holding
means, in one of these positions, is in contact with the second
section of the respective second spring element such that this
second section is held in the predetermined position relative to
the support part and is separated from the second section of the
respective second spring element in the other one of these
positions.
[0038] The support structure can comprise an actuating means for
moving the respective holding means from one of these positions
into another one of the positions. The actuating means makes it
possible for the user to move the respective holding means in a
simple manner and to thus impact the respective state of the
coupling device. In the event that the support structure comprises
a plurality of second spring elements and accordingly a plurality
of first and second holding means for holding the respective second
spring elements, it is advantageous to design a single actuating
means such that all of the movable holding means can be moved with
this actuating means independent on one another.
[0039] The actuating means can be a rotatable cam shaft, for
example, on which at least one cam, which is assigned to the
respective holding means, is arranged such that the respective
holding means can be moved by means of the respective assigned cam
in response to a rotation of the cam shaft.
[0040] In the event that the support structure comprises a
plurality of second spring elements and accordingly a plurality of
first and second holding means for holding the respective second
spring elements, the cam shaft can be embodied such that a
plurality of cams are embodied on the cam shaft such that the
respective second spring elements can in each case be coupled
successively to the base support as well as to the support part in
response to a rotation of the cam shaft beyond a predetermined
range of the angle range of rotation. In this case, the number of
the second spring elements, which are in each case coupled to the
base support as well as to the support part and which accordingly
generate a reset force in response to a movement of the support
part, can be increased successively by rotating the cam shaft.
[0041] An elastomer torsion spring element, which comprises an
inner housing, an outer housing surrounding the inner housing and
an elastomer body, which is arranged in a space between the inner
housing and the outer housing, for example, can be used as first
and/or second spring element of the respective power system of the
respective support structures. Said inner housing encompasses at
least one contact surface, at which the elastomer body is in
contact with the inner housing. Said outer housing encompasses at
least one contact surface, at which the elastomer body is in
contact with the outer housing, wherein the elastomer body is
fixedly connected to the contact surface of the inner housing and
to the contact surface of the outer housing and wherein the inner
housing and/or the outer housing is arranged so as to be capable of
being rotated about an axis of rotation.
[0042] In the event that the respective first spring element is
embodied in the form of the afore-mentioned elastomer torsion
spring element, this elastomer torsion spring element can then be
coupled to the base support and to the support part such that the
respective movement of the support part causes a rotation of the
inner housing and/or of the outer housing about the axis of
rotation such that the inner housing is moved relative to the outer
housing in response to the rotation and a deformation of the
elastomer body is thereby generated, so that the elastomer body
generates a reset torque between the outer housing and the inner
housing, which is directed opposite to the rotation. Accordingly,
in the event that the respective second spring element is embodied
in the form of the above-mentioned elastomer torsion spring
element, this elastomer torsion spring element can be coupled to
the base support and to the support part by means of the respective
coupling device such that the respective movement of the support
part causes a rotation of the inner housing and/or of the outer
housing about the axis of rotation such that the inner housing is
moved relative to the outer housing in response to the rotation and
a deformation of the elastomer body is thereby generated, so that
the elastomer body generates a reset torque between the outer
housing and the inner housing, which is directed opposite to the
rotation. The reset torque is accompanied by a reset force, which
acts on the support part, due to the mentioned coupling between the
outer housing or the inner housing, respectively, and the base
support or the support part, respectively.
[0043] Elastomer torsion spring elements of the aforementioned type
have the advantage that they make it possible to realize the
respective power system in a particularly compact (space-saving)
manner and that they provide for a coupling of the respective
spring element to the base support and to the support part, which
can be realized by means of particularly simple means. This applies
in particular when the respective support part is attached to a
bearing shaft, which is supported on the base support such that the
support part can be pivoted about a pivot axis. In this case, the
respective elastomer torsion spring element can be coupled to the
base support and to the support part, for example, such that the
outer housing is rigidly connected to the base support and that the
inner housing is rigidly connected to the support part or to the
bearing shaft. In the alternative, the inner housing can be rigidly
connected to the base support and the outer housing can be rigidly
connected to the support part or to the bearing shaft. The inner
housing of the respective elastomer torsion spring element can
thereby be realized in the form of a ring-shaped structure, which
can be attached onto the bearing shaft such that the inner housing
surrounds the bearing shaft in a ring-shaped manner. In the
alternative, the bearing shaft can be realized in the form of a
pipe and the elastomer torsion spring element can be installed into
the pipe.
[0044] Advantageously, the respective elastomer torsion spring
element of the afore-mentioned type can be formed such that the
contact surface of the inner housing encompasses a non-circular
cross section in a sectional plane, which is vertical to the axis
of rotation and/or that the contact surface of the outer housing
encompasses a non-circular cross section in a sectional plane,
which is vertical to the axis of rotation. The mentioned cross
sections of the inner housing or of the outer housing,
respectively, can be embodied so as to be angular, for example, and
can encompass the form of a square or of a rectangle, for example.
This has the advantage that the reset torque, which generates such
an elastomer torsion spring element when the outer housing is
twisted about a certain angle of rotation relative to the inner
housing, varies to a relatively high degree with the angle of
rotation. Such an elastomer torsion spring element thus makes it
possible to generate a relatively large reset torque in response to
a predetermined angle of rotation (as compared to the elastomer
torsion spring element known from EP 1486142 A1, the inner housing
and the outer housing of which in each case encompass contact
surfaces, which adjoin the respective elastomer body and the cross
section of which encompasses the shape of a circle in a sectional
plane, which is vertical to the axis of rotation). The reset torque
furthermore displays a linear rise as function of the angle of
rotation across a relatively large area of the angle of
rotation.
[0045] In an alternative of the above-mentioned elastomer torsion
spring elements, at least one holding element can be arranged in
each case on the respective elastomer torsion spring element, with
said holding element being designed [0046] to hold the inner
housing of the elastomer torsion spring element in a predetermined
basic position relative to the outer housing of the elastomer
torsion spring element, with the elastomer body encompassing a
predetermine elastic deformation in said basic position and
generating a reset torque, which equals a predetermined minimum
value, between the outer housing and the inner housing and [0047]
to release a rotation of the inner housing relative to the outer
housing about an angle of rotation about the axis of rotation in a
direction of rotation, in which the reset torque increases with an
increasing angle of rotation.
[0048] Accordingly, the elastomer body of this elastomer torsion
spring element is prestressed when the inner housing of the
elastomer torsion spring element is in the respective basic
position. Such an elastomer torsion spring is thus able, in
response to any small deflection of the support part out of a basic
position, to generate a reset force, which acts on the support part
and which is always greater than a minimum value (greater than 0).
Accordingly, a reset force can be generated, which acts on the
support part and which is sufficient to support a relatively heavy
person even if the support part is in a basic position. In the case
of a power system comprising a plurality of spring elements,
different spring elements can also be prestressed to varying
degrees, so that they generate different-sized reset forces.
[0049] The holding element of the afore-mentioned type can be
realized in different ways.
[0050] In one embodiment, the holding element includes at least one
clamping element, which either encompasses a first section, which
is fixedly engaged with the inner housing, and which encompasses a
second section, which strikes against a section of the outer
housing--when the inner housing is in the predetermined basic
position relative to the outer housing--and releases a rotation of
the inner housing and of the outer housing in relation to one
another about the axis of rotation in that direction of rotation,
in which the reset torque increases. Advantageously, this
embodiment provides the opportunity for a plurality of elastomer
torsion spring elements, the inner housings of which are connected
to one another in a torsionally rigid manner, to be prestressed
together in a single operating step. This simplifies the assembly
of a power system comprising a plurality of elastomer torsion
spring elements, which are to be prestressed in a predetermined
basic position. In the alternative, the clamping element can also
encompass a first section, which is fixedly engaged with the outer
housing and can encompass a second section, which strikes against a
section of the inner housing--when the inner housing is in the
predetermined basic position relative to the outer housing--and
releases a rotation of the inner housing and of the outer housing
in relation to one another about the axis of rotation in that
direction of rotation, in which the reset torque increases.
[0051] In a further alternative, the inner housing comprises a
recess. The first section of the clamping element is furthermore
inserted into this recess in the inner housing in a torsionally
rigid manner and the second section of the clamping element strikes
against a section of the outer housing when the inner housing is in
the predetermined basic position relative to the outer housing.
This alternative makes it possible for the elastomer body of an
individual elastomer torsion spring element of the afore-mentioned
type to be prestressed initially in that the outer housing is
twisted relative to the inner housing. After the clamping element
has been inserted into the recess in the inner housing as
mentioned, the outer housing is held in a basic position such that
the prestress of the elastomer body is retained. The elastomer
torsion spring element, which is prestressed in such a manner, has
the advantage that, together with the clamping element, it forms a
modular unit, which (in the prestressed state) can be transported
as a whole and can be assembled into a support structure according
to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] Further details of the invention and in particular exemplary
embodiments of the support structure according to the invention
will be specified below in connection with a seat assembly by means
of the enclosed drawings.
[0053] FIG. 1 shows a part of a seat assembly in the form of an
office chair in a first perspective illustration, comprising a
support structure according to an embodiment of the invention for a
back part and a seat of the seat assembly;
[0054] FIG. 2 shows the support structure according to FIG. 1,
comprising a base support and a support part, which can be moved
relative to the base support, for the back part and the seat in a
perspective illustration;
[0055] FIGS. 3A, 3B show in each case the support structure
according to FIG. 2 in a side view, wherein FIG. 3A shows the
support structure in a state, in which the support part is in a
basic position and FIG. 3B shows the support structure in a state,
in which the support part is deflected out of the basic
position;
[0056] FIGS. 4A, 4B show a view of the support structure according
to FIG. 2 in a perspective illustration, wherein the support part
and other components are removed, so as to provide for a view onto
a power system of the support structure, including different spring
elements in the form of elastomer torsion spring elements and onto
coupling devices;
[0057] FIGS. 5A-5C show a detailed view of the support structure
according to FIGS. 4A and 4B in a perspective illustration, wherein
the spring elements and the coupling devices of the power system
are shown in different states;
[0058] FIGS. 6A, 6B show a further detailed view of the power
system according to FIGS. 5A-5C in a schematic detailed
illustration, wherein the coupling devices are shown in different
states;
[0059] FIGS. 7A, 7B show an exemplary embodiment of an elastomer
torsion spring element in a cross section (FIG. 7A) and this
elastomer torsion spring element in combination with a holding
element, which holds the elastomer torsion spring element in a
prestressed state, in a perspective illustration (FIG. 7B);
[0060] FIGS. 8A-8C show an illustration of a power system
comprising elastomer torsion spring elements and holding elements,
which hold the respective elastomer torsion spring elements in a
prestressed state, wherein the respective holding elements form a
different embodiment, as compared to the holding element according
to FIG. 7B;
[0061] FIGS. 9A-9E show a device for producing the power system
illustrated in FIGS. 8A-8C; and
[0062] FIGS. 10A, 10B show an alternative for a support of the
support part on the base support of the support structure.
DETAILED DESCRIPTION
[0063] FIG. 1 shows an exemplary embodiment of a seat assembly in
the form of a chair 10. The chair 10 is embodied as an office
swivel chair. It comprises a support column 12, a back part 20, a
seat 24 and a support structure 13 according to an embodiment of
the invention for the back part 20 and for the seat 24. The support
structure 13 holds the back part 20 and the seat 24 in a basic
position in each case, provided that no load acts on the back part
20 or on the seat 24, respectively, and makes it possible for the
back part 20 or the seat 24, respectively, to be able to be
deflected out of the respective basic position, provided that a
load acts on the back part or on the seat 24, respectively. In the
illustration according to FIG. 1, the back part 20 or the seat 24,
respectively, are unloaded and are thus in the respective basic
position. In this basic position, the back part 22 is oriented in a
substantially vertical manner and the seat 24 is oriented in a
substantially horizontal manner.
[0064] As is suggested in FIG. 1, the support structure comprises a
base support 14 (see FIG. 2), among others, which is arranged on an
upper end of the support column 12 (if applicable so as to be
rotatable about a vertical axis and being height-adjustable) in the
instant example, and a support part 16. One end of this support
part 16 is rigidly connected to a bearing shaft 18, which is
supported on the base support 14 such that it can be rotated about
its longitudinal direction. Accordingly, the support part 16 is
arranged so as to be rotatable together with the bearing shaft 18
and thus on the base support 14 in a pivotable manner.
[0065] The base support 14 furthermore serves as a housing for
accommodating mechanical elements, which will be described below,
in particular in context with FIGS. 2-10.
[0066] The back part 20 comprises a backrest 22 and a connecting
piece 21, which is embodied as an angle profile, wherein the
backrest 22 is attached to a journal of this angle profile and the
other journal of this angle profile serves to attach the back part
20 to the support part 16. As is suggested in FIGS. 1 and 2, the
support part 16 on the end, which is detached from the bearing
shaft 18, encompasses a channel comprising an opening adapted to
the outer contour of the connecting piece 21. The end of the
connecting piece 21, which is spaced apart from the backrest 22,
can be inserted into this channel and can subsequently be brought
alongside this channel into a position relative to the support part
16, in which the connecting piece 21 (comprising means, which are
not illustrated in the figures) can be fixed to the support part
16. Fixed to the support part 16 in such a manner (as is
illustrated in FIG. 1), the back part 20 is accordingly rigidly
coupled to the bearing shaft 18 via the support part 16 and is thus
arranged on the base support 14 in a pivotable manner.
[0067] The seat 24 is located on a seat support 28, which can be
pivoted about a pivot axis in the instant case. The seat support 28
is attached to the support part 16 (as is suggested in FIG. 3A).
The seat support 28 is thus supported on the support part 16 at
least in a partial area. Another partial area of the seat support
28 can be supported on the base support 14.
[0068] The afore-described arrangement of the support part 16, of
the back part 20 and of the seat support 28 on the base support 14
makes it possible for a person sitting on the chair 10 to be able
to lean back with the backrest 22 and for the seat support 28 and
thus the seat surface 24 to be capable of being pivoted at the same
time synchronous to this.
[0069] To make it possible for the back part 20 and the seat 24 to
be able to assume a stable position even if the back part 20 and
the seat 24 are moved relative to the basic position illustrated in
FIG. 1 with reference to the base support 14, the support structure
13 additionally comprises a power system (not illustrated in FIG.
1), which generates a reset force or a reset torque, respectively.
Said reset force acts on the support part 16 or between the support
part 16 and the base support 14 and counteracts a movement of the
support part 16 relative to the basic position illustrated in FIG.
1. This power system will be specified below in context with FIGS.
2-10.
[0070] In the case of the support structure 13, the support part 16
accordingly supports the back part 20 and the seat 24 and keeps the
back part 20 and the seat 24 in a position, which is a function of
the relative position of the support part 16 with reference to the
base support 14.
[0071] FIG. 2 shows, in a perspective illustration, the support
structure 13 according to FIG. 1 including the base support 14 and
the support part 16 and the seat support 28, wherein the back part
20, backrest 22 and the seat 24 are removed and are accordingly not
illustrated in FIG. 2. As is suggested in FIG. 2, the bearing shaft
18 is connected in a positive fit to the support part 16 in a
torsionally rigid manner via a connecting piece 26, which is
attached to the support part 16. The seat support 28, to which in
turn the seat 24 illustrated in FIG. 1 can be attached, is arranged
above the base support 14. In the instant example, the support part
16 assumes the basic position and can, based on this basic
position, be pivoted clockwise (based on the perspective
illustrated in FIG. 2) about the longitudinal direction of the
bearing shaft 18. The seat support 28 can follow via the mechanical
coupling of the respective pivoting motion of the support part 16,
which is described in combination with FIG. 1. The base support 14
is embodied in a housing-type manner and surrounds a power system
30, for example, for generating a reset force or a reset torque,
respectively. Said reset force acts on the support part 16 or said
reset torque acts between the support part 16 and the base support
14, respectively, and is oriented opposite to a movement of the
support part 16 relative to the base support 14.
[0072] FIGS. 3A and 3B show in each case the support structure 13
illustrated in FIG. 2 in a side view, wherein the base support 14
assumes in each case the same position in the room in FIG. 3A as
well as in FIG. 3B. FIG. 3A shows the support structure 13 in a
state, in which the support part 16 is in the basic position. FIG.
3B shows the support structure 13 in a state, in which the support
part 16 is deflected out of the basic position, that is, it is
rotated or pivoted clockwise, respectively, relative to the basic
position.
[0073] The state illustrated in FIG. 3B is reached as soon as a
person sitting on the chair 10 leans back against the backrest 22
(not shown in FIG. 3B) and thereby exerts a force onto the backrest
22 and thus onto the support part 16, so that the backrest 22 and
thus the support part 16 carries out a pivoting motion. Following
the pivoting motion of the support part 16, the seat support 28 is
also moved relative to the base support 14 in the situation
according to FIG. 3B (as compared to the situation according to
FIG. 3A). The seat 24 illustrated in FIG. 1 is thus also moved
synchronous to the backrest 22 under the conditions as
mentioned.
[0074] FIGS. 4A and 4B show the support structure 13, which is
illustrated in FIG. 2. To make details of the base support 14 and
of the power system 30 to be more visible, the support part 16 and
the seat support 28 are not illustrated in FIGS. 4A and 4B.
[0075] The power system 30 according to FIGS. 4A and 4B comprises a
plurality of spring elements for generating a reset force: a
"first" spring element 32 and three "second" spring elements 33',
33'' and 33''' in the instant example. The spring elements 32, 33',
33'' and 33''' are in each case embodied in the form of an
elastomer torsion spring element, the structure and mode of
operation of which will be described in more detail below, in
particular in context with FIG. 7A.
[0076] In context with the facts illustrated in FIGS. 4A and 4B, it
is only relevant initially that the first spring element 32 and the
second spring elements 33', 33'' and 33''' in each case comprise an
inner housing 43, an outer housing 44 surrounding the inner housing
43 and an elastomer body 46. The elastomer body 46 is arranged in a
space between the inner housing 43 and the outer housing 44, as is
illustrated in FIG. 7A. The elastomer body 46 is fixedly connected
to the inner housing 43 on the one side as well as to the outer
housing 44. The elastomer body 46 is deformed elastically in the
event that the inner housing 43 is moved relative to the outer
housing 44 and then generates a reset force between the inner
housing 43 and the outer housing 44, which counteracts this
movement. A reset torque is accordingly generated between the inner
housing 43 and the outer housing 44 in the event that the inner
housing 43 is twisted relative to the outer housing 44.
[0077] The inner housing 43 of each of the spring elements 32, 33',
33'', and 33''' encompasses a continuous channel, the cross section
of which is embodied such that the bearing shaft 18 can be guided
through this channel and each of the spring elements 32, 33', 33''
and 33''' can be attached to the bearing shaft 18 such that the
respective inner housing 43 of each of the spring elements 32, 33',
33'' and 33''' is connected to the bearing shaft 18 in a positive
fit and sits on the bearing shaft 18 such that the respective inner
housing 43 is connected to the bearing shaft 18 in a torsionally
rigid manner.
[0078] As is suggested in FIGS. 4A and 4B, the first spring element
32 and the second spring elements 33', 33'' and 33''' are attached
to the bearing shaft 18 such that they sit next to one another on
the bearing shaft 18 in the above-mentioned order.
[0079] The first spring element 32 of the power system 30 is
coupled to the base support 14 as well as to the support part 16 in
the following manner: a first section of the first spring element
32, that is the inner housing 43 of the first spring element 32,
is--as already specified--connected to the bearing shaft 18 in a
torsionally rigid manner and is thus rigidly coupled to the bearing
shaft 18 and thus also to the support part 16. The inner housing 43
is rotated about the axis of rotation of the bearing shaft 18 in
response to a pivoting motion of the support part 16. Furthermore,
a second section of the first spring element 32, the outer housing
44 of the first spring element 32, is rigidly connected to the base
support 14 (which cannot be seen from FIGS. 4A and 4B, but which
can be identified from the illustration of the power system 30 in
FIG. 5B). In response to a pivoting motion of the support part 16,
the bearing shaft 18 and the inner housing 43 of the first spring
element 32 are thus together rotated about the axis of rotation
(longitudinal axis) of the bearing shaft 18, while the outer
housing 44 remains positioned in a stationary manner with reference
to the base support 14. Accordingly, the inner housing 43 and the
outer housing 44 of the first spring element 32 are rotated
relative to one another in response to a pivoting motion of the
support part 16. Accordingly, the elastomer body 46 of the first
spring element 32 is deformed elastically, so that the first spring
element 32 generates a reset torque, which acts on the bearing
shaft 18 or on the support part 16, respectively, and which
counteracts the pivoting motion of the support part 16.
[0080] According to an embodiment of the invention, the power
system 30 provides the opportunity to bring the second spring
elements 33', 33'' and 33''' in each case into a state (referred to
hereinbelow as "coupled state"), in which the respective spring
element 33', 33'' or 33''' is coupled to the base support 14 and to
the support part 16 and to further bring it into another state
(referred to hereinbelow as "uncoupled state"), in which the
respective second spring element 33', 33'' or 33''' is not coupled
to the base support 14 and/or to the support part 16.
[0081] For this purpose, the power system 30 comprises a coupling
mechanism 34 for coupling the respective second spring element 33',
33'' or 33''' to the base support 14 and/or to the support part 16.
The coupling mechanism 34 is attached to the base support 14 and
can (as will be specified in more detail below) be brought into
different states, in which the coupling mechanism 34 interacts
either with the respective second spring element 33', 33'' or 33'''
such that the respective second spring element 33', 33'' or 33'''
is in the coupled state and is capable in this state to generate a
reset force, which acts on the support part 16 or interacts such
that the respective spring element 33', 33'' or 33''' is in the
uncoupled state and is not capable in this state to generate a
reset force, which acts on the support part 16.
[0082] In the instant example, the coupling mechanism 34 comprises
a total of three "coupling devices", wherein one of these coupling
devices is in each case assigned to one of the respective second
spring elements 33', 33'' or 33''', respectively.
[0083] The "coupling device" assigned to the second spring element
33' comprises: [0084] a first holding means 36' for holding a
"first section" of the spring element 33', wherein the outer
housing 44 of this spring element is considered to be the "first
section" of the spring element 33' and [0085] a second holding
means for holding a "second section" of the spring element 33',
wherein the inner housing 43 of this spring element is considered
to be the "second section" of the spring element 33' and in this
context the afore-mentioned second holding means is understood to
be the already mentioned positive connection between the inner
housing 43 of the spring element 33' and the bearing shaft 18.
[0086] The first holding means 36' for holding the outer housing 44
of the second spring element 36' is embodied in the form of a
movable part, which is attached to the base support 14 and which
(as will be specified below in more detail) can be brought into a
"first" position on the one hand, in which the first holding means
36' is brought into contact with the outer housing 44 of the second
spring element 33' and holds the outer housing 44 in a
predetermined position relative to the base support 14 and, on the
other hand, can be brought into a "second" position, in which the
first holding means 36' is not in contact with the outer housing 44
of the second spring element 33'.
[0087] It follows from this that the first holding means 36' is a
means for holding the outer housing 44 of the second spring element
33' so as to be capable of being detached, wherein the outer
housing 44 is only held by the first holding means 36' when the
holding means 36' is in the mentioned first position, and the outer
housing 44 is separated (detached) from the first holding means 36'
in the event that the first holding means 36' is in the second
position.
[0088] The afore-mentioned "coupling device", which is assigned to
the second spring element 33', has the characteristic that the
outer housing 44 of the second spring element 33' is connected to
the base support 14 when the first holding means 36' is brought
into the mentioned first position and the inner housing 43 of the
second spring element 33' is rigidly connected to the bearing shaft
18 and is thus rigidly connected to the support part 16. In this
case, the second spring element 33' is in the already mentioned
coupled state. However, if the first holding means 36' is brought
into the mentioned second position, the outer housing 44 of the
second spring element 33' is not connected to the base support 14.
According to this assumption, the first spring element 33' is in
the uncoupled state. In this case, the second spring element 33' is
rotated together with the bearing shaft 18 as a whole in response
to a rotation of the bearing shaft 18 about the longitudinal
direction thereof. The inner housing 43 of the second spring
element 33' is not twisted relative to the outer housing 44 and the
elastomer body 46 of the second spring element 33' is not deformed.
Accordingly, the second spring element 33' cannot generate a reset
force, which acts on the support part 16 and which counteracts this
pivoting motion, in response to a pivoting motion of the support
part 16, in the event that the first holding means 36' is in the
second position.
[0089] Those "coupling devices" of the coupling mechanism 34, which
are assigned to the respective second spring elements 33'' and
33''', are constructed analogous to those coupling devices, which
were previously described in context with the second spring element
33', with reference to their structure and function. Accordingly,
the coupling mechanism 34 comprises (analogous to the first holding
means 36') a first holding means 36'' for detachably holding the
outer housing 44 of the second spring element 33'' and a first
holding means 36''' for detachably holding the outer housing 44 of
the second spring element 33'''. Accordingly, the coupling
mechanism 34 furthermore comprises (analogous to the mentioned
second holding means for the second spring element 33') a second
holding means for holding the inner housing 43 of the spring
element 33' (realized in the form of the already mentioned positive
connection between the inner housing 43 of the second spring
element 33'' and the bearing shaft 18) and a second holding means
for holding the inner housing 43 of the second spring element 33'''
(realized in the form of the already mentioned positive connection
between the inner housing 43 of the second spring element 33''' and
the bearing shaft 18).
[0090] As is suggested in FIGS. 4A and 4B, the first holding means
36', 36'' and 36'''' are arranged next to one another in a row such
that they can be pivoted about a pivot axis 37, which is oriented
parallel to the bearing shaft 18 and which is arranged in a
stationary manner relative to the base support 14. The first
holding means 36', 36'' and 36''' can in each case be pivoted about
the pivot axis 37 such that they can selectively be brought into
contact with the outer housing 44 of the respective assigned second
spring element 33', 33'' or 33''', respectively (in the first
position of the respective holding means) or can be separated from
the respective outer housing (in the second position of the
respective holding means).
[0091] As is furthermore suggested in FIGS. 4A and 4B, the support
structure 13 comprises an actuating means (control device) 38 for
moving the respective first holding means 36', 36'' and 36'''. In
the instant example, the actuating means 38 comprises a rotatable
cam shaft 39, on which cams 40', 40'' and 40''' are arranged, which
in each case (in this order) are assigned to one of the first
holding means 36', 36'' and 36'''. The cams 40', 40'' and 40''' are
formed such that they control the first holding means 36', 36'' and
36''' individually or in combination with one another in response
to a rotation of the cam shaft 39 (about the longitudinal axis of
the cam shaft 39), so as to pivot the first holding means 36', 36''
and 36''' in each case about the pivot axis 37 and, if necessary,
to be able to bring them into contact with the outer housing 44 of
the respective assigned second spring element 33', 33'' or 33''',
respectively.
[0092] FIGS. 4A and 4B show the cam shaft 39 in a position, in
which the respective cams 40', 40'' and 40''' are arranged such
that all first holding means 36', 36'' and 36''' are arranged such
that none of the first holding means 36', 36'' and 36''' is brought
into contact with one of the second spring elements 33', 33'' or
33''', respectively. Accordingly, all second spring elements 33',
33'' or 33''', respectively, are in the uncoupled state. In this
case, the first spring element 32 is accordingly coupled to the
base support 14 as well as to the support part 16. In this case,
only the first spring element 32 generates a reset torque acting on
the bearing shaft 18 or on the support part 16, respectively, which
counteracts the pivoting motion of the support part 16 or the
rotation of the bearing shaft 18, respectively, in response to a
pivoting motion of the support part 16 or in response to a
corresponding rotation of the bearing shaft 18, respectively.
[0093] FIG. 4B shows the coupling mechanism 34 illustrated in FIG.
4A from a different perspective. Outer housing cams 42'-42''',
which are in each case attached or integrally molded to,
respectively, to the outer housings 44 of the second spring
elements 33'-33''', can be identified hereby. These outer housing
cams 42'-42''' are arranged such that the first holding means
36'-36''', which is brought into the first position by means of a
corresponding actuation of the actuating means 38, is in each case
brought into contact with the corresponding outer housing cams
42'-42''' and forms a mechanical stop for this outer housing cam.
The respective outer housing 44 of the respective second spring
element 33', 33'' or 33''', respectively, is accordingly coupled to
the base support 14 via the respective outer housing cam 42'-42'''
by means of the coupling mechanism 34.
[0094] FIGS. 5A-5C show a detailed view of the support structure
13, wherein the spring elements 32, 33', 33'' or 33''',
respectively, and the coupling mechanism 34 of the power system are
shown in different states. The support part 16 and the seat support
28 are not illustrated in FIGS. 5A-5C (for clarifying the
illustrated facts).
[0095] The cams 40'-40''' in FIG. 5A are oriented by means of a
suitable rotation of the cam shaft 39 such that the first holding
means 36'-36''' is in the second position and are accordingly not
brought into contact with the outer housing cams 42'-42''' of the
second spring elements 33'-33'''. All second spring elements 33',
33'' or 33''', respectively, are accordingly in the uncoupled
state. The position of the bearing shaft 18 illustrated in FIG. 5A
corresponds to the basic position of the support part 16. In this
situation, none of the spring elements 32, 33', 33'' or 33''',
respectively, generates a reset torque, which acts on the bearing
shaft 18. Based on the position of the bearing shaft 18 illustrated
in FIG. 5A, the bearing shaft 18 can be rotated in the direction of
the arrow 18', so as to provide for a pivoting motion of the
support part 16. Such a rotation can be caused, for example, by a
person sitting on the seat assembly 10 according to FIG. 1 when
leaning back against the backrest 22. In response to a rotation of
the bearing shaft in the direction of the arrow 18', only the first
spring element 32 would generate a reset torque acting on the
bearing shaft 18 (according to the situation illustrated in FIGS.
4A and 4B).
[0096] FIG. 5B illustrates a state of the power system 30, which
differs from the state illustrated in FIG. 5A in that the first
holding means 36''' is now in the first position (and is
accordingly brought into contact with the outer housing cam 42'''
of the second spring element 33''', which is not visible in FIG.
5B). The state of the power system 30 in FIG. 5B also differs from
the state illustrated in FIG. 5A in that the bearing shaft 18 is
rotated counter clockwise about a certain angle of rotation (that
is, in the direction of the arrow 18'). Accordingly, the coupling
mechanism 34 is in a state, in which the second spring element
33''' is in the coupled state and the second spring elements 33'
and 33'' are in the uncoupled state. As becomes clear from a
comparison with FIG. 5A, the spatial position of the outer housing
44 of the first spring element 32 and the spatial position of the
outer housing of the second spring element 33''' is unchanged in
the state according to FIG. 5B (as compared to the situation
according to FIG. 5A), while the respective inner housings 43 of
the spring elements 32 and 33''' are rotated about the axis of
rotation of the bearing shaft 18 in the direction of the arrow 18'
together with the bearing shaft 18 (due to the rigid coupling of
the inner housings of the spring elements 32 and 33''' to the
bearing shaft 18). The spring elements 32 and 33''' accordingly
generate a reset torque in each case, which acts on the bearing
shaft 18 (contrary to the rotation of the bearing shaft 18 in the
direction of the arrow 18').
[0097] As becomes clear from a comparison with FIG. 5A, the second
spring elements 33' and 33'' are rotated as a whole in the
direction of the arrow 18' about the axis of rotation of the
bearing shaft 18 in the state according to FIG. 5B, in particular
because the outer housing 44 of the second spring elements 33' and
33'' are not coupled to the base support 14 by means of the first
holding means 36' or 36'', respectively. According to this, the
second spring elements 33' and 33'' do not generate a reset torque
acting on the bearing shaft 18 in the situation according to FIG.
5B.
[0098] FIG. 5C shows a state of the power system 30 or of the
coupling mechanism 34, respectively, in which all second spring
elements 33'-33''' are in the coupled state: by means of a suitable
rotation of the cam shaft 39, the cams 40'-40''' are oriented such
that the first holding means 36'-36''' are in the first position
and are accordingly brought into contact with the outer housing
cams 42'-42''' of the second spring elements 33'-33'''. In this
situation, the outer housings 44 of all of the spring elements 32,
33'-33''' are locked in a stationary position relative to the base
support 14. In response to a rotation of the bearing shaft 18 in
the direction of the arrow 18', the inner housing of the respective
spring element 32, 33'-33''' would accordingly be twisted in each
case relative to the outer housing 44 of the respective spring
element 32, 33'-33''', so that all of the spring elements 32,
33'-33''' in each case generate a reset torque, which acts on the
bearing shaft 18.
[0099] As specified above, a (total) reset torque acts on the
bearing shaft 18 in each case, with said reset torque corresponding
to the sum of all of the reset torques generated by those spring
elements 32, 33'-33''', which are in each case in the coupled state
and are accordingly coupled to the base support 14 as well as to
the support part 16. Due to the fact that only the first spring
element 32 is in the coupled state in the state of the power system
30 illustrated in FIG. 5A, the power system 30 in the state
according to FIG. 5A generates a reset torque with the smallest
possible value, in response to a rotation of the bearing shaft 18
by a predetermined angle of rotation .phi. and is thus adjusted in
this state to persons having a relatively low weight. Due to the
fact that, in the state of the power system 30 illustrated in FIG.
5C, all second spring elements 33'-33''' are in the coupled state
in addition to the first spring element 32, the power system 30
generates a reset torque with the largest possible value in
response to a rotation of the bearing shaft 18 about the same
(above-mentioned) angle of rotation .phi. and is thus adjusted in
this state to persons having a relatively large weight.
[0100] In the state according to FIG. 5B, the power system 30
accordingly generates a reset torque in response to a rotation of
the bearing shaft 18 about the same (above-mentioned) angle of
rotation .phi., the value of which lies between the corresponding
values of the reset torque generated by the power system 30 in the
states according to FIGS. 5A and 5C and is thus adjusted to persons
having an average weight.
[0101] FIGS. 6A and 6B show a schematic view of the power system 30
together with the coupling mechanism 34 and actuating means 38,
wherein the base support 14 is not illustrated, so as to more
clearly show details of the individual spring elements 32,
33'-33''' (in particular the outer contours thereof and the
arrangement thereof on the bearing shaft 18). In the example
according to FIG. 6A, the cam shaft 39 is rotated such that the
cams 40'-40''' are positioned such that only the first holding
means 36' is brought into the first position and only the second
spring element 33' (except for the first spring element 32) is thus
in the coupled state. FIG. 6B shows the coupling mechanism 34 in a
state, in which none of the second spring elements 33'-33''' is
transferred into the coupled state. Accordingly, the situation
illustrated in FIG. 6B is identical to the situation illustrated in
FIG. 5A.
[0102] FIG. 7A shows a schematic side view of the second spring
element 33' in a sectional plane, which is perpendicular to an axis
of rotation 47. The spring elements 32, 33'' and 33''' are
identical to the spring element 33' with reference to their
structural design, so that the characteristics of the spring
elements 32 and 33'-33'' are to be specified below by means of the
spring element 33' according to FIG. 7A. As already mentioned, the
second spring element 33' (as are the spring elements 32, 33'' and
33''') is embodied as an elastomer torsion spring element and
comprises an inner housing 43 and an outer housing 44. An elastomer
body 46 is arranged in a space between the inner housing 43 and the
outer housing 44.
[0103] On its outer side, the inner housing 43 encompasses a
contact surface 43a, on which the elastomer body 46 is in contact
with the inner housing 43. On its inner side, the outer housing 44
furthermore encompasses a contact surface 44a, on which the
elastomer body 46 is in contact with the outer housing 44. The
contact surface 43a of the inner housing 43 and the contact surface
44a of the outer housing 44 enclose the axis of rotation 47 in a
ring-shaped manner in each case. Accordingly, the elastomer body 46
in the instant example forms a closed ring, which surrounds the
axis of rotation 47.
[0104] The elastomer body 46 consists of an elastomer, that is, a
fixed and elastically deformable material. The elastomer body 46 is
embodied such that it is fixedly connected to the contact surface
43a of the inner housing 43 and to the contact surface 44a of the
outer housing 44. That is, a displacement of the surfaces of the
elastomer body 46 abutting on the contact surfaces 43a and 44a
relative to the contact surfaces 43a and 44a does not take place in
response to a movement of the inner housing 43 relative to the
outer housing (e.g. in response to a rotation of the inner housing
43 or of the outer housing 44 about the axis of rotation 47). The
elastomer body 46 can be connected to the inner housing 43 and to
the outer housing 44 by means of material engagement or in a
form-fit manner on the contact surfaces 43a or 44a,
respectively.
[0105] An elastomer, which is particularly well-suited for the
production of the elastomer body 46, is a rubber, for example,
which is not only an elastically deformable and high-tensile
material, but which can also be fixedly connected to the contact
surfaces 43a and 44a in a simple manner such as, for example, by
means of vulcanizing.
[0106] The inner housing 43 and the outer housing 44 are made from
a solid material such as, for example, steel. The respective
contact surfaces 43a and 44a of the inner housing 43 or of the
outer housing 44, respectively, which in each case adjoin the
elastomer body 46--in a sectional plane, which is perpendicular to
the axis of rotation 47--differ from a circular design, at least in
sections. Due to this special form, pressure loads, which
compensate tensile forces therein, appear in several areas of the
elastomer body 46, in response to the rotation of the inner housing
43 about the axis of rotation 47 in relation to the outer housing
44. The elastomer body 46 is thus not loaded in a homogenous
manner.
[0107] In FIG. 7A, the inner housing 43 is shown in an "untwisted"
state (solid line) and in a "twisted state" (dotted line). In the
twisted state, as compared to the untwisted state, the inner
housing 43 is twisted clockwise about an angle of rotation .phi.
about the axis of rotation 47, while the position of the outer
housing 44 remains unchanged thereby. It is assumed that the
elastomer body 46 is not prestressed in the case of the untwisted
state, that is, that is does not encompass any mechanical stresses.
In the untwisted state, the distances from the upper right-hand
corner or the lower left-hand corner, respectively, of the inner
housing 43 to respective defined points on the inner side of the
outer housing 44 are in each case shown by means of arrows x1 or
y1, respectively. In the twisted state, the distances from the
upper right-hand corner or the lower left-hand corner,
respectively, of the inner housing 43 to respective defined points
on the inner side of the outer housing 44 are in each case
identified by means of arrows x2 or y2, respectively. As can be
seen in FIG. 7A, the distance x2 is smaller than x1 and the
distance y2 is smaller than y1. The elastomer body 46 is thus
compressed in this area when the inner housing 43 is rotated about
the axis of rotation 47 and is thereby rotated relative to the
outer housing 44. The above-mentioned pressure loads result from
these respective compressions.
[0108] After a rotation of the inner housing 43 about the angle of
rotation .phi. about the axis of rotation 47, the elastomer body 46
is deformed and generates a reset torque D between the outer
housing 44 and the inner housing 43, which is directed opposite to
the rotation and which increases with the angle of rotation
.phi..
[0109] The fact that the distances x2-xl and y2-y2 are reduced in
response to a rotation of the inner housing 43 about the angle of
rotation .phi., is a result of the fact that the cross section of
the contact surface 43a or of the contact surface 44a, respectively
is not circular (in a cutting surface vertical to the axis of
rotation 47). The result of the geometric deviation of the
mentioned cross sections of the contact surfaces 43a or 44a,
respectively, from a circularity is that, in response to a rotation
of the inner housing 43 about the angle of rotation .phi., a
spatial distribution of the mechanical stress results in the
elastomer body 46, which is not rotationally symmetrical to the
axis of rotation 47. This is contrary to the spatial distribution
of the mechanical stresses in an elastomer torsion spring element
according to EP 1486142 A1, which is rotationally symmetrical to
the axis of rotation 47 in each case. These differences with
reference to the stress distribution lead to considerable
differences with reference to the dependencies of the reset torque
D as a function of the angle of rotation .phi.. In particular,
these differences cause an elastomer torsion spring element
comprising the form illustrated in FIG. 7A to show a considerably
greater increase of the reset torque D as function of the angle of
rotation .phi. than the elastomer torsion spring element according
to EP 1486142 A1.
[0110] In the embodiment illustrated in FIG. 7A, the contact
surface 43a of the inner housing 43, which adjoins the elastomer
body 46, is formed so as to be square. The inner housing 43 is
hereby embodied as a square sleeve (square), which encompasses a
channel 43.1 comprising a square cross section and extending
parallel to the axis of rotation 47. The shape of the cross section
of the channel 43.1 is adapted to the cross sectional shape of the
bearing shaft 18, so that the bearing shaft 18 can be inserted
through the channel 43.1 and the inner housing 43 can sit on the
bearing shaft 18--being connected to the bearing shaft 18 in a
positive fit (as already mentioned in context with FIGS. 4A and
4B).
[0111] The contact surface 44a of the outer housing 44 adjoining
the elastomer body 46 has a contour, which is to be considered to
be a combination of a rectangle and a circle. More specifically,
the contour of the outer housing 44 is comprised of two
equal-legged angular segments, which are located opposite one
another in pairs and which draw an angle of 90.degree. in the
instant example, and of two semi circle segments, which are located
opposite to one another in pairs and the ends of which are in each
connected to the ends of the mentioned angular segments. By means
of a plurality of test series, which were carried out, it was
determined that this seemingly "lemon-shaped" contour of the outer
housing 44, in combination with the square contour of the inner
housing 43, is particularly advantageous for creating an elastomer
torsion spring element, the characteristic curve of the reset
torque D of which runs linear in virtually all areas of the angle
of rotation .phi. in relation to the angle of rotation .phi..
[0112] FIG. 7A further shows the outer housing cam 42', which is
embodied on the outer housing 44 and which was already mentioned in
context with FIGS. 4B and 5A-5C.
[0113] FIG. 7B shows the second spring element 33' illustrated in
FIG. 7A with a holding element 48 in a perspective illustration.
The holding element 48 serves the purpose of holding the inner
housing 43 and the outer housing 44 in a "basic position" relative
to one another, in which the elastomer body 46 encompasses a
mechanical stress (prestress) and thus generates a reset torque D
between the inner housing 43 and the outer housing 44, which is
different from zero. In this "basic position", the inner housing 43
is twisted about an angle of rotation .DELTA..phi. (hereinbelow
referred to as "prestress angle") as compared to the "untwisted"
position (without prestress) according to FIG. 7A, namely clockwise
with reference to FIG. 7A and counter clockwise with reference to
FIG. 7B. In this example, the holding element 48 includes two
clamping elements 49, which are in each case attached to one of the
front sides of the second spring element 33'.
[0114] The clamping element 49 is a substantially flat plate, the
center area of which is punched such that two flanges 50', 50'',
which are located opposite one another, remain. These flanges are
in each case curved inward by 90.degree. (into the figure plane).
Straps 52', 52'', which are also curved inward by 90.degree., are
embodied on an outer area of the clamping element 49.
[0115] For assembling the respective clamping element 49 to the
second spring element 33', the flanges 50', 50'', which are
embodied such that the outer areas thereof can be connected to the
inner surface of the inner housing 43 in a positive fit, are
inserted into the inner housing 43 about a first distance. Then,
the clamping element 49 and the inner housing 43, which is
connected thereto in a positive fit in radial direction, are
twisted counter clockwise about a certain angle (for example)
20.degree. in relation to the outer housing 44.
[0116] Subsequently, the clamping element 49 is pushed completely
into the channel 43.1 of the inner housing 43 with its flanges 50',
50'', wherein the straps 52', 52'' assume a positive connection
with the outer surface of the outer housing at the same time.
Assembled in this manner, the clamping element 49 maintains the
prestress. More specifically, the prestress angle .DELTA..RTM. can
no longer be fallen below, because the straps 52', 52'' strike
against the outer surface of the outer housing 44. However, an
increase of the rotational displacement (also counter clockwise)
between the inner housing 43 and the outer housing 44 is possible.
In response to an increase of this rotational displacement, the
inner areas of the straps 52', 52'' slide along the outer surface
of the outer housing 44 or are removed therefrom. To prevent a
destruction of the second spring element 33', a maximum angle of
rotation (for example 70.degree.) is not to be exceeded between the
inner housing 43 and the outer housing 44 in this example. This is
so, because the strap 52' strikes against the outer housing cam 42'
in the case of the maximum angle of rotation .phi., thus
advantageously preventing a further rotation.
[0117] The clamping element 49 can also be used in combination with
the spring elements 32, 33'' and 33''' analogous to the example
illustrated in FIG. 7B. It is pointed out that in the case of the
power system 30, the respective second spring elements 33', 33''
and 33''' are in each case illustrated in combination with two
clamping elements 49 in the illustrations according to FIGS. 4A,
4B, 5A-5C, 6A and 6B, which corresponds to the clamping elements 49
according to FIG. 7B (as is suggested in particular in FIGS. 6A and
6B).
[0118] Accordingly, each of the second spring elements 33', 33''
and 33''' of the power system 30 generates a reset torque, which
acts on the bearing shaft 18 in each case, in response to a
rotation of the bearing shaft 18, with said reset torque being
greater or equal to a predetermined minimum value (different from
zero), provided that the respective second spring element 33', 33''
or 33''', respectively, is in the coupled state.
[0119] FIGS. 8A-8C show (in different views) an alternative of the
power system 30 according to FIGS. 3A-6B. The power system 30
according to FIGS. 8A-8C differs from the power system 30 according
to FIGS. 3A-6B substantially in that it comprises clamping elements
54', 54'', 54''' and 54'''' (as replacement for the type of
clamping elements 49 shown in FIG. 7B). Clamping elements 54',
54'', 54''' and 54''' differ from the clamping elements 49
according to FIG. 7B with reference to their construction. The
alternative of the power system 30 according to FIGS. 8A-8C
accordingly also comprises (as does the power system 30 according
to FIG. 3A-6B) the bearing shaft 18, the first spring element 32
and the second spring elements 33', 33'' and 33'''. The coupling
mechanism 34 and the actuating means 38 are not illustrated in
FIGS. 8A-8C.
[0120] The clamping elements 54'-54'''' are plate-like elements,
the inner areas of which are punched in a rectangular manner. The
contour of the punch is hereby adapted in a positive fit to the
outer contour of the (square) bearing shaft 18. Curvatures
55'-55'''', which in each case include a through hole, are
integrally molded on the outer areas of the clamping elements
54'-54''''.
[0121] In response to the assembly of the power system 30, the
bearing shaft 18 and the inner housing 32 of the first spring
element 32 are connected to one another in a positive fit in radial
direction. A first clamping element 54' is subsequently attached
onto the bearing shaft 18 across its punch, so that a positive
connection in radial direction is also established between the
bearing shaft 18 and the clamping element 54'. The second spring
element 33' is subsequently attached to the bearing shaft 18.
Following this step, a further clamping element 54'' is attached,
etc. After all three second spring elements 33'-33''' have been
attached onto the bearing shaft 18 with clamping elements
54'-54''', which have been placed therebetween in each case, the
last clamping element 54'''' is finally attached on the front
side.
[0122] Subsequently, the second spring elements 33'-33''' are
prestressed either individually or at the same time, in that their
outer housings, for example, are rotated clockwise about the
longitudinal direction of the bearing shaft 18 in response to a
radially fixed bearing shaft 18. This rotation takes place up to an
angle or rotation, at which pins 56', 56'' can be inserted through
the respective holes of the curvatures 55'-55''''. After the pins
56', 56'' have been inserted through these holes, the introduction
of force for turning the outer housings is ended. In this state,
the outer housings 44 of the individual second spring elements
33'-33''' remain in this position, because the respective outer
surfaces of the outer housings 44 now strike against a peripheral
section of the pins 56', 56''. It is thus now no longer possible
for the respective outer housings 44 to be turned back into the
initial state.
[0123] An advantage of the arrangement and of the embodiment of the
clamping elements 54'-54'''' is that, contrary to the examples
shown in FIGS. 6A, 6B and 7B, a flange is now no longer inserted
into the respective inner housings 43 of the second spring elements
33'-33'''. The bearing shaft 18 is thus in a positive engagement in
radial direction with the entire inner surface of the respective
inner housings 43. A play between the bearing shaft 18 and the
inner housing 43 of the respective second spring element 33'-33'''
is thus avoided. A bearing clearance, however, appears in the case
of the example illustrated in FIGS. 6A and 6B, which is based on
the fact that introduction of the reset torques of the respective
second spring elements 33'-33''' into the bearing shaft 18 takes
place section by section via the flanges 50', 50'' of the
respective clamping element 49 and that the inner housings 43 of
the respective second spring elements 33'-33''' can accordingly not
be in mechanical contact with the bearing shaft 18 (see FIGS. 6A,
6B and 7B).
[0124] A further advantage of the example shown in FIGS. 8A-8C lies
in that the assembly is much simpler as compared to the example
illustrated in FIGS. 6A and 6B, in the case of which each elastomer
torsion spring element was first equipped with its clamping
elements 49.
[0125] In addition, the assembly time is markedly shortened. A
further advantage lies in the much simpler and less time-intensive
production of the individual clamping element 54'-54''''. They can
only be produced in a cost-efficient manner by means of
punches.
[0126] FIGS. 9A-9E show different views of a clamping device 58 for
prestressing the spring elements 33'-33''' shown in FIGS. 8A-8C
comprising the clamping elements 54'-54'''' attached therebetween
and on the front side. In FIGS. 9A and 9C, the clamping device 58
is in each case illustrated in full view, viewed from different
directions. In FIGS. 9B and 9D, the clamping device 58 is in each
case illustrated in a detailed view, viewed from different
directions. The clamping device 58 serves to easily and quickly
prestress the individual spring elements 33'-33''' with only a few
steps. The clamping device 58 includes fixing devices 60, which fix
the bearing shaft 18 (not shown) so as to be fixed on its axial
ends. As is specified for describing FIGS. 8A-8C, the individual
spring elements 33'-33''' are first attached to the bearing shaft
18, wherein the clamping elements 54'-54'''' are in each case
attached therebetween and on the front side. These clamping
elements 54'-54'''' are in each case connected to the bearing shaft
18 in a positive fit in radial direction.
[0127] The clamping device 58 further includes a rod 62, which is
connected vertically between two lever arms of a lever 64. The
lever arms are pivotably articulated via clamping device bearings
66', 66''. The lever 64 can be deflected back and forth at its
lower end via a drive 68. In response to a deflection of the lower
section of the lever 64 in a direction out of the figure plane of
FIG. 9A, the rod 62 is deflected towards the spring elements
33'-33''', as is suggested by an arrow A.
[0128] As can be seen particularly well in FIGS. 9C-9E, a surface
area of the rod 62 initially engages with an area of the outer
surface of the outer housing of a first spring element, in this
example with the outer housing 44 of the second spring element
33''' (for example via the outer housing cam 42''') in a first
stage of the deflection of the rod 62 in the direction of the arrow
A.
[0129] Starting at a second stage of the deflection of the rod 62
in the direction of the arrow A, a further surface area of the rod
62 engages with the outer surface of the outer housing of a further
spring element, in this example with the outer housing 44 of the
second spring element 33''. During the deflection of the rod 62
between the first stage and the second stage, the outer surface of
the outer housing 44 of the second spring element 33''', which was
previously brought into engagement, is also rotated or twisted,
respectively. In a third stage of the deflection of the rod 62 in
the direction of the arrow A, an area of the outer surface of the
outer housing of a further spring element, in this example the
outer housing 44 of the second spring element 33', is engaged.
During the deflection of the rod 62 between the second stage and
the third stage, the second spring elements 33''' and 33'' are
deflected or twisted, respectively. In a fourth stage of the
deflection of the rod 62, all spring elements 33'-33''' are now
deflected or twisted, respectively, parallel to one another such
that the pins 56', 56'', which are also illustrated in FIGS. 8A-8C,
can be inserted through the holes of the respective curvatures
55'-55'''' of the individual clamping elements 54'-54''''. As soon
as the pins 56', 56'' have been inserted through the mentioned
holes, the mentioned deflection of the rod 62 is reversed, that is,
the rod is moved opposite to the arrow direction A. The used pins
56', 56'' abut on the individual outer surfaces of the outer
housings of the second spring elements 33'-33''' and are clamped
due to the effect of the reset torques of the second spring
elements 33'-33'''. The pins 56', 56'' are furthermore in each case
held by means of the clamping elements 54'-54'''', which are
coupled in a torsionally rigid manner in radial direction. The
individual second spring elements 33'-33''' can thus no longer
return into the respective non-deflected initial state (FIGS.
9A-9E).
[0130] FIG. 9E shows the clamping device 58 in a view in axial
direction to the clamping device bearings 66', 66''. It can be seen
particularly clearly in this figure that the individual second
spring elements 33'-33''' are deflected differently in each case in
their initial state. This is due to the fact that the respective
inner housings of the second spring elements 33'-33''' are arranged
in relation to the contour of their respective outer housings in
each case comprising a rotational displacement, which has a
different size for the second spring elements 33'-33''' in each
case. The rotational displacements for the second spring elements
33'-33''' can be 20.degree., 25.degree. and 40.degree. for example.
Due to the respective different rotational displacement between the
inner housing 43 and the outer housing 44, the individual second
spring elements 33'-33''' are thus also prestressed to varying
degrees. In this example, the second spring element 33''' is thus
prestressed more than the second spring element 33'', which in turn
is prestressed less than the second spring element 33'. As is
suggested in FIGS. 9A and 9C-9E, the pins 56', 56'' can be inserted
through the holes of the curvatures 55'-55'''' of the respective
clamping elements 54'-54'''' after the prestressing. The respective
prestressing of the individual second spring elements 33'-33''' is
thus maintained by means of the pins 56', 56''.
[0131] This prestress cannot be fallen below, but the outer
housings 44 of the individual second spring elements 33'-33''' can
be further rotated relative to the corresponding inner housings 43
in a direction of rotation such that the reset torque generated by
the respective second spring element 33'-33''' is increased as the
angle of rotation increases, until the outer housing cams
42'-42''', which are integrally molded on the respective outer
housing 44, strike against the pin 56'. In this state, the second
spring elements 33'-33''' have reached their maximally permissible
angle of rotation and in each case provide for the largest possible
reset torque.
[0132] The clamping device 58 illustrated in FIGS. 9A-9E and the
methods described with reference thereto in an exemplary manner
show that the afore-described power system 30 can be produced very
quickly and with only a few movements even in the case of
differently prestressed second spring elements 33'-33'''.
[0133] FIG. 10A shows a support structure 13a according to another
embodiment of the invention, which represents an alternative of the
support structure 13 according to FIG. 2. Those components, which
together encompass the support structures 13 and 13a will be
identified hereinbelow with the same reference numerals.
[0134] The support structure 13a according to FIG. 10A
comprises--as does the support structure 13 according to FIG. 2--a
base support 14 and a support part 16 (for supporting and/or
holding the back part 20 and/or the respective seat 24 according to
FIG. 1). The support part 16 is connected to the ends of a
rotatable bearing shaft 18 via a connecting piece 26 in a
torsionally rigid manner, so that the support part 16 can be
pivoted in the direction of the arrow 18' about the longitudinal
axis of the bearing shaft 18.
[0135] FIG. 10B also shows the support structure 13a according to
FIG. 10A the only difference being that the support part 16 is not
illustrated in FIG. 10B.
[0136] The support structure 13a comprises a power system 30a,
which comprises two first spring elements 32a and second spring
elements 33', 33'' and 33'''. The spring elements 32a, 33', 33''
and 33''' are in each case designed as elastomer torsion spring
element and are identical with the spring element 33' according to
FIG. 7A with reference to their structure. That is, the spring
elements 32a, 33', 33'' and 33'''encompass in each case an inner
housing 43, an outer housing 44 surrounding the inner housing 43,
and an elastomer body 46, which is arranged in the space between
the inner housing 43 and the outer housing 44, and which is fixedly
connected to the inner housing 43 and the outer housing 44. The
second spring elements 33', 33'' and 33''' of the power system 30a
are identical with the spring elements 33', 33'' and 33''' of the
power system 30. With reference to its construction, the first
spring element 32a of the power system 30a differs from the first
spring element 32 of the power system 30 substantially in the shape
of the cross section of the outer housing 44, as is suggested in
FIG. 10B. The latter, however, is not important with reference to
the function of the first spring element 32a in this context.
[0137] As is suggested in FIG. 10B, the spring elements 32a, 33',
33'' and 33''' of the power system 30a are located on the bearing
shaft 18 such that the inner housing 43 of the spring elements are
in each case connected to the bearing shaft in a torsionally rigid
manner. As is further suggested in FIG. 10B, the outer housing 44
of the respective first spring element 32a is connected to the base
support 14 in a torsionally rigid manner, while the inner housing
43 together with the bearing shaft 18 can be rotated in the
direction of the arrow 18'. The two first spring elements 32a are
accordingly coupled to the base support 14 as well as to the
support part 16, so that the first spring elements 32a generate a
reset torque in each case in response to a pivoting motion of the
support part in the direction of the arrow 18', with said torque
being oriented opposite to the pivoting motion of the support part
16.
[0138] The second spring elements 33', 33'' and 33''' of the power
system 33a correspond to the second spring elements 33', 33'' and
33''' of the power system 30 from a functional point of view. The
support structure 13a also comprises the same coupling mechanism 34
and the actuating means 38 for controlling the coupling mechanism
such that the respective second sprig elements 33', 33'' and 3'''
can be brought either into the coupled state (in which the
respective second spring element 33', 33'' and 33''' is coupled to
the base support 14 as well as to the support part 16 via the
coupling mechanism 34) or into the uncoupled state (in which the
respective spring element 33', 33'' and 33''' is not coupled to the
base support 14 and/or to the support part 16).
[0139] An important feature of the support structure 13a is to be
seen in that the support part 16 and the two ends of the bearing
shaft 18 are always coupled to the base support 14 via the
elastomer bodies 46 of the two first spring elements 32a, wherein
the elastomer bodies 46 can accommodate a load, which acts radially
on the bearing shaft 18. In the case of the support structure 13a,
the bearing shaft 18 accordingly does not require a separate
swivel, which supports the bearing shaft 18 rotatably on the base
support 14. In the instant case, the first spring elements 32a
serve as bearing for the bearing shaft 18, in particular when none
of the second spring elements 33'-33''' is switched into the
coupled state. In the event that one of the second spring elements
33'-33''' is in the coupled state, this spring element also serves
as support for the bearing shaft 18 with reference to the base
support 14.
[0140] The spring elements 32a thus carry out a double function: as
means for generating a reset force/torque acting on the support
part 16 and as bearing for the support of the bearing shaft 18. An
advantage of this arrangement lies in that separate swivels are not
necessary through this. Costs are thus reduced. In addition, this
arrangement saves space. A further advantage lies in that forces
appearing radially to the bearing shaft 18 can be accommodated by
means of the elastomer body 46 between the inner housing 43 and the
outer housing 44 of the first spring element 32a. This arrangement
thus achieves an advantageous elastic coupling between the base
support 14 and the support part 16, which increases the seating
comfort.
[0141] While the invention has been described and illustrated with
reference to certain particular embodiments thereof, those skilled
in the art will appreciate that various adaptations, changes,
modifications, substitutions, deletions, or additions of procedures
and protocols may be made without departing from the spirit and
scope of the invention. It is intended, therefore, that the
invention be defined by the scope of the claims that follow and
that such claims be interpreted as broadly as is reasonable.
* * * * *