U.S. patent application number 10/532458 was filed with the patent office on 2006-06-29 for transmission amplifier assembly for a bowden cable and method of using the same.
This patent application is currently assigned to SCHUKRA GERATEBAU AG. Invention is credited to Robert Kopetzky, Veit Stobel.
Application Number | 20060138829 10/532458 |
Document ID | / |
Family ID | 32107054 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060138829 |
Kind Code |
A1 |
Kopetzky; Robert ; et
al. |
June 29, 2006 |
Transmission amplifier assembly for a bowden cable and method of
using the same
Abstract
A bowden cable transmission device (10') is provided between the
bowden cable actuator (16) and the lumbar support member (14) of an
adjustable lumbar support assembly (12). The bowden cable
transmission device converts movement of a first wire portion (52)
of a bowden cable (18) attached to the bowden cable actuator (16)
into movement of a second wire portion (26) attached to the lumbar
support member (14) in accordance with a predetermined transmission
ratio such that a movement or adjustment of the second wire portion
(26) is facilitated.
Inventors: |
Kopetzky; Robert; (Graz,
AT) ; Stobel; Veit; (Nurnberg, DE) |
Correspondence
Address: |
HUSCH & EPPENBERGER, LLC
190 CARONDELET PLAZA
SUITE 600
ST. LOUIS
MO
63105-3441
US
|
Assignee: |
SCHUKRA GERATEBAU AG
Leobersdorfer Strabe 26
Berndorf
AT
A-2560
|
Family ID: |
32107054 |
Appl. No.: |
10/532458 |
Filed: |
October 27, 2003 |
PCT Filed: |
October 27, 2003 |
PCT NO: |
PCT/EP03/11909 |
371 Date: |
December 16, 2005 |
Current U.S.
Class: |
297/284.1 |
Current CPC
Class: |
F16H 21/44 20130101;
B60N 2/6671 20150401 |
Class at
Publication: |
297/284.1 |
International
Class: |
A47C 7/46 20060101
A47C007/46 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 25, 2002 |
US |
10/280921 |
Claims
1. An adjustable lumbar support assembly, comprising: an adjustable
lumbar support member; a Bowden cable actuator for actuating a
Bowden cable having a first wire portion and a second wire portion;
and a transmission amplifier assembly for the Bowden cable, the
transmission amplifier assembly comprising a rotary member being
supported rotatably, the Bowden cable with the first wire portion
being connected between the Bowden cable actuator and the
transmission amplifier assembly and with the second wire portion
being connected between the transmission amplifier assembly and the
adjustable lumbar support member, and the first wire portion and
the second wire portion of the Bowden cable being both coupled to
the rotary member such that movement of the first wire portion
imparts rotation of the rotary member and thereby movement of the
second wire portion in accordance with a predetermined transmission
ratio, the movement of the second wire portion being facilitated
compared to the movement of the first wire portion by the
predetermined transmission ratio.
2. The adjustable lumbar support assembly according to claim 1,
wherein the transmission amplifier assembly is arranged such that
the movement of the first wire portion imparts the movement of the
second wire portion, which is increased by the predetermined
transmission ratio with respect to the movement of the first wire
portion.
3. The adjustable lumbar support assembly according to claim 1,
wherein the first wire portion and second wire portion both are
directly fixed at the rotary member.
4. The adjustable lumbar support assembly according to claim 1,
wherein the first wire portion and the second wire portion extend
both along a periphery of the rotary member.
5. The adjustable lumbar support assembly according to claim 4,
wherein the first wire portion and the second wire portion extend
both along respective grooves formed in the periphery of the rotary
member.
6. The adjustable lumbar support assembly according to claim 1,
wherein the rotary member has a substantially longitudinal
shape.
7. The adjustable lumbar support assembly according to claim 6,
wherein the rotary member has a substantially elliptic shape.
8. The adjustable lumbar support assembly according to claim 1,
wherein the rotary member has a substantially increasing width from
a portion of the rotary member where the first wire portion leaves
the periphery of the rotary member to a portion of the rotary
member where the second wire portion leaves the periphery of the
rotary member.
9. The adjustable lumbar support assembly according to claim 1,
wherein the rotary member is supported rotatable around a point of
rotation, the point of rotation being arranged eccentrically in a
longitudinal direction of the rotary member.
10. The adjustable lumbar support assembly according to claim 1,
wherein the first wire portion and the second wire portion are
formed by a single wire movable in the sleeve of the Bowden
cable.
11. The adjustable lumbar support assembly according to claim 1,
wherein the sleeve of the Bowden cable is held in place by a
holding member.
12. The adjustable lumbar support assembly according to claim 1,
wherein a guiding member for guiding the first wire portion towards
the rotary member and a guiding member for guiding the second wire
portion from the rotary member are provided.
13. The adjustable lumbar support assembly according to claim 12,
wherein the guiding member for the first wire portion and the
guiding member for the second wire portion are formed by a common
guiding member.
14. The adjustable lumbar support assembly according to claim 1,
wherein the transmission amplifier assembly is arranged such that a
lever arm defined between the second wire portion and a point of
rotation of the rotary member is larger than a lever arm defined
between the first wire portion and the point of rotation by a
predetermined transmission ration.
15. The adjustable lumbar support assembly according to claim 1,
wherein the transmission amplifier assembly is attached to the
adjustable lumbar support member.
16. A method of adjusting a lumbar support member, comprising the
steps: causing motion of a first wire portion of a Bowden cable
relative to a sleeve of the Bowden cable via a Bowden cable
actuator; converting the motion of the first wire portion into
motion of a second wire portion in accordance with a predetermined
transmission ratio, the conversion being such that the motion of
the second wire portion being facilitated compared to the motion of
the first wire portion by the predetermined transmission ratio;
adjusting the lumbar support member in response to the motion of
the second wire portion.
17. The method according to claim 16, wherein the motion of the
first wire portion is converted into the motion of the second wire
portion using said transmission amplifier assembly.
Description
[0001] This invention pertains to the field of bowden cable
actuator assemblies. More particularly, the invention pertains to a
transmission amplifier assembly and a corresponding transmission
device for and a method of converting motion of the wire of a
bowden cable, i.e. a first wire portion, into motion of a further
wire, i.e. a second wire portion, according to a predetermined
transmission ratio. For example, the conversion of the motion of
the first wire portion into the motion of the second wire portion
may be non-proportional, thereby allowing a constant rate motion of
the first wire portion to result in a non-constant rate motion of
the second wire portion. The preferred embodiments of the invention
are specifically developed for use in adjustable lumbar support
assemblies of automobile seats.
[0002] Adjustable lumbar support assemblies are widely used in
automobile-seats. Many adjustable lumbar support assemblies
comprise an adjustable lumbar support that is connected to an
actuator via a bowden cable. The bowden cable of such assemblies
transmits motion and power from the actuator to the lumbar support
member to allow adjustment of the contour of the lumbar support
member. Bowden cables are flexible conduits or sleeves containing
wires that slide axially through the conduit.
[0003] The adjustable lumbar support member of an assembly is
typically a thin panel flexible member that is positioned in the
seat where it will support the lumbar region of a person's back
when the person is seated therein. Typically, the lumbar support
member is made adjustable by changing its curvature in a manner
such that it extends more or less toward the person's back. Several
different methods are commonly used to change the curvature of the
lumbar support member. One method is to apply a bending moment to
either the top or bottom end margin of the support member in a
manner such that the support portion's curvature increases or
decreases. Another common method is to force the top and bottom end
margins of the support member toward each other such that the
support member bows outward.
[0004] One end of a bowden cable is typically attached to the
support member to either supply the necessary bending moment to the
end margin of the support portion or to force the end margins
together and to hold the support member in any given position. The
opposite end of the bowden cable is then attached to an actuator
device that is typically either manually or electromechanically
operated to tension the wire of the bowden cable and thereby to
adjust the lumbar support portion of the seat.
[0005] During use of a typical adjustable lumbar support assembly,
the tension of the wire of the bowden cable increases exponentially
as the curvature of the support portion is increased. Thus, the
actuator must also exert exponentially increasing tension on the
wire of the bowden cable as the curvature of the support portion is
increased. As a result, the design of both manually and
electromechanically operated actuators is typically driven by the
requirement of being able to provide peak tension. In light of this
design concern, typical prior art actuators are generally
inefficient during initial flexing of the lumbar support when the
tension required is low.
[0006] A second design concern is the need to maximize lumbar
support travel in relation to actuator movement. It is inconvenient
for a passenger to have to turn an actuator lever or wheel many
times to move the lumbar support. User convenience will be provided
to the extent that a bowden cable at the lumbar support end can be
made to travel a farther distance than the distance the actuator
pulls it at the user's end.
[0007] Finally, there is a constant need to decrease component size
and cost.
[0008] Accordingly, the object of the present invention is to
provide a solution to the above problems and, in particular, to
provide an assembly and a method which allow efficient flexing of a
lumbar support at small component size and small cost.
[0009] According to the present invention, this object is achieved
by a transmission amplifier assembly for a bowden cable as defined
by claim 1 and a method of adjusting a lumbar support member as
defined by claim 27. The dependent claims define preferred and
advantageous embodiments of the invention.
[0010] The present invention overcomes the disadvantages of prior
art adjustable lumbar support assemblies having a lumbar support
member by providing a bowden cable transmission between the
actuator and the lumbar support member that converts movement of a
first wire portion or a first wire of a bowden cable to be attached
to the actuator into movement of a second wire portion or a second
wire to be attached to the lumbar support member in accordance with
a predetermined transmission ratio.
[0011] In particular, the bowden cable transmission is such that
the movement of the second wire portion is lightened or relieved
compared to the movement of the first wire portion by the
predetermined transmission ratio. This may be accomplished by the
movement of the second wire portion being increased by the
predetermined transmission ratio with respect to the movement of
the first wire portion.
[0012] The bowden cable transmission may convert the motions in a
non-proportional manner such that the movement of the second wire
portion in response to the movement of the first wire portion
changes as the movement of the first wire portion is altered. In an
adjustable lumbar support assembly, the non-proportional conversion
allows movement of the first wire portion by the actuator to invoke
larger movement of the second wire portion when the lumbar support
member is relaxed and to invoke less movement in the second wire
portion in response to the movement of the first wire portion when
the lumbar support member is substantially flexed.
[0013] In general, the bowden cable transmission assembly of the
invention comprises a bowden cable having a sleeve and the first
wire portion, which can also be regarded as an input wire portion,
and the second wire portion which may be arranged in a further
sleeve of a further bowden cable and which can also be regarded as
an output wire portion. The assembly further comprises a
transmission device effecting the predetermined transmission
ratio.
[0014] According to an embodiment of the invention, the
transmission device comprises two pairs of connection points. The
first pair has first and second connection points that are movable
relative to each other. The first connection point is operatively
connected to the sleeve of the bowden cable and the second
connection point is operatively connected to the first wire portion
in a manner such that movement of the first wire portion relative
to the sleeve imparts movement of the first connection point
relative to the second connection point. The transmission device
also comprises third and fourth connection points that are movable
relative to each other. The third connection point may be
operatively connected to the further sleeve of the further bowden
cable, and the fourth connection point is operatively connected to
the second wire portion in a manner such that movement of the third
connection point relative to the fourth connection point imparts
movement of the second wire portion relative to the third
connection point. The first, second, third, and fourth connection
points may be linked to each other in a manner such that movement
of the first wire portion relative to the sleeve causes
non-proportional movement of the second wire portion relative to
the third connection point.
[0015] According to another embodiment of the invention, the
transmission device comprises a rotary member being supported
rotatably. The first wire portion and the second wire portion both
are coupled to the rotary member and preferably directly attached
or fixed to the rotary member such that the movement of the first
wire portion imparts rotation of the rotary member and, in
addition, thereby imparts the movement of the second wire portion.
The first wire portion and the second wire portion preferably
extend both along a periphery of the rotary member or are wound at
least partially around the rotary member. The first wire portion
and the second wire portion may extend both along respective
grooves formed in the periphery of the rotary member.
[0016] The rotary member preferably has a longitudinal shape, for
example a substantially elliptic shape, the width of the rotary
member at least slightly increasing from a portion of the rotary
member where the first wire portion leaves or comes into contact
with the periphery of the rotary member to a portion of the rotary
member where the second wire portion leaves or comes into contact
with the periphery of the rotary member. The rotary member is
supported rotatably around a point of rotation, the point of
rotation being in particular arranged eccentrically with respect to
the end portions of the rotary member in the longitudinal direction
of the rotary member.
[0017] By this arrangement, movement of the first wire portion
imparts rotation of the rotary member and consequently movement of
the second wire portion such that the above mentioned predetermined
transmission ration is achieved by the ratio of the smaller lever
arm/motion arm defined between the first wire portion and the point
of rotation of the rotary member and the larger lever arm/motion
arm defined between the second wire portion and the point of
rotation of the rotary member.
[0018] Preferably, in this further embodiment of the invention, the
first wire portion and the second wire portion are formed by one
single wire which runs from the sleeve of the bowden cable to the
rotary member, where it is fixed, and then to the lumbar support
member.
[0019] The invention also provides a method of adjusting a lumbar
support, for example of a seatback, that comprises the step of
causing motion of a first wire portion of a bowden cable relative
to a sleeve of the bowden cable via a bowden cable actuator. The
method also comprises converting the motion of the first wire
portion into motion of a second wire portion, the conversion being
such that the motion of the second wire portion is lightened
compared to the motion of the first wire portion by a predetermined
transmission ratio. The method further comprises adjusting the
lumbar support in response to the motion of the second wire
portion.
[0020] The method may in particular use the bowden cable
transmission assembly or the transmission device thereof as
described above.
[0021] While the principle advantages and features of the invention
have been described above, a more complete and thorough
understanding of the invention may be attained by referring to the
drawings and the detailed description of the preferred embodiments
which follow.
[0022] FIG. 1 is an oblique view of an adjustable lumbar support
assembly with a transmission device of the present invention
schematically shown assembled thereto.
[0023] FIG. 2 is a side view of a typical prior art lumbar support
member shown in a generally relaxed position.
[0024] FIG. 3 is a side view of the typical prior art lumbar
support member of FIG. 2 shown in a flexed position.
[0025] FIG. 4 is an oblique view of a first embodiment of the
transmission device of the present invention shown in a relaxed
position where bowden cables attached thereto are unstressed.
[0026] FIG. 5 is an oblique view of the first embodiment of the
transmission device shown in a contracted position where the bowden
cables attached thereto are fully tensioned.
[0027] FIG. 6 is an oblique view of a second embodiment of the
transmission device of the present invention shown in a relaxed
position where the bowden cables attached thereto are
unstressed.
[0028] FIG. 7 is an oblique view of the second embodiment of the
transmission device shown in a contracted position where the bowden
cables attached thereto are fully tensioned.
[0029] FIG. 8 is a top view of a third embodiment of the
transmission device of the invention attached to a lumbar support
member.
[0030] FIG. 9 is a top view of the third embodiment of the
transmission device when the lumbar support member is in a relaxed
position.
[0031] FIG. 10 is a top view of the third embodiment of the
transmission device when the lumbar support member is in a flexed
position.
[0032] Reference characters in the written specification indicate
corresponding parts throughout the several views of the
drawings.
[0033] The preferred embodiments of the bowden cable transmission
device are configured and adapted for use in adjustable lumbar
support assemblies of automobiles.
[0034] FIG. 1 illustrates a bowden cable transmission device 10 in
accordance with the present invention schematically shown assembled
as part of an adjustable lumbar support assembly 12.
[0035] In addition to the bowden cable transmission device 10, the
lumbar support assembly 12 comprises a lumbar support member 14, a
bowden cable actuator 16, a first bowden cable 18, and a second
bowden cable 20. The lumbar support member 14 is preferably a
typical prior art support member formed of plastic, metal, or other
suitable materials and is capable of resiliently deflecting. As
shown, the lumbar support member 14 generally has the shape of a
thin panel and is attached to a generally rigid seatback frame 22
where it is adapted to support a person's lower back. By applying a
tensile force between the opposite top and bottom end margins of
the lumbar support member 14, the curvature and contour of the
lumbar support member 14 can be controlled or adjusted to achieve a
desired level of comfort. As shown in FIGS. 2 and 3, the tensile
force is applied via a bowden cable, which in this particular
lumbar support assembly 12 is the second bowden cable 20.
[0036] In FIG. 2, the lumbar support member 14 is shown in a
relaxed or undeflected state and the wire 26 of the second bowden
cable 20 extends a maximum amount from the cable's sleeve 28. The
terminal end of the sleeve 28 of the bowden cable 20 is attached to
one of the end margins of the lumbar support member 14 via a tether
24 and the wire 26 is attached to the other end margin. In FIG. 3,
the wire 26 of the second bowden cable 20 has been partially
retracted into the cable's sleeve 28, thereby creating a tensile
force between the end margins of the lumbar support member 14
causing it to deflect as shown.
[0037] Alternatively, any other type of bowden cable actuated
lumbar support members could be used. For example, although not
shown, the lumbar support member could be of the type that is
flexed by applying various bending moments to one or both of the
opposite top and bottom end margins of the lumbar support member.
Such bending moments are commonly induced by applying a force on
one or more moment arms that typically extend from the backside of
the lumbar support member. Some other lumbar supports extend a
paddle from a mount or channel. Again, a bowden cable would supply
the necessary force. Thus, various types of adjustable lumbar
support members could be utilized in connection with the invention
and the particular type utilized is not critical to the
invention.
[0038] The bowden cable actuator 16 of the lumbar support assembly
12 is preferable a typical prior art bowden cable actuator that is
either manually or electomechanically operated. The bowden cable
actuator 16 is configured and adapted, as is well know in the prior
art, to selectively and controllably apply a tensile force on the
wire of a bowden cable. In the lumbar support assembly 12 of FIG.
1, the bowden cable actuator 16 is connected to the first bowden
cable 18 and, as described below, supplies the force and motion
necessary to cause the deflection of the lumbar support member
14.
[0039] It should be appreciated that in a typical prior art lumbar
support assembly, a single bowden cable often connects the lumbar
support member to the actuator. It should be further appreciated
that the lumbar support assembly 12 of FIG. 1 differs from the
assemblies of the prior art only in that the first bowden cable 18
extending from the bowden cable actuator 16 is connected to the
second bowden cable 20 extending from the lumbar support member 14
via the bowden cable transmission device 10. Thus, particular
aspects of the lumbar support member, the connection between the
lumbar support member and the second bowden cable, the bowden cable
actuator, and the connection between the bowden cable actuator and
the first bowden cable are not critical to the invention and
various alternatives known in the prior art or developed in the
future could be also utilized with the present invention.
[0040] Having described the relative placement of the bowden cable
transmission device 10 in the lumbar support assembly 12, a first
embodiment of the bowden cable transmission device 10' is shown in
FIG. 4 and 5. As shown, the first embodiment of the bowden cable
transmission device 10' generally comprises a plurality of
tensioning members 30 that are connected to each other by a
plurality of linking members 32. The tensioning members 30 and the
linking members 32 are preferably formed of plastic, metal, or
other suitable materials that are capable of transmitting
loads.
[0041] Each of the tensioning members 30 of the first embodiment of
the bowden cable transmission device 10' is generally bar shaped
and has a pivot connection 34 at each of its opposite longitudinal
ends. A through-hole 36 extends laterally through the center of
each of the tensioning members 30. A counterbore 38 is formed in
each through-hole 36 and creates a recessed annular surface (not
shown). Each of the linking members 32 of the first embodiment of
the bowden cable transmission device 10' is also generally bar
shaped and has a pivot connection 40 at each of its opposite
longitudinal ends. The pivot connections 40 of the linking members
32 are complementary to the pivot connections 34 of the tensioning
members 30.
[0042] The tensioning members 30 are connected to each other by the
linking members 32 via the pivot connections 34, 40. As assembled,
a first pair 42 of tensioning members 30 are oriented spaced apart
and with their respective through-holes 36 aligned and the
counterbores 38 facing away from each other. Likewise, the
remaining two tensioning members 30 are oriented spaced apart with
their respective through-holes 36 aligned and the counterbores 38
facing away from each other. The through-holes 36 of the second
pair 44 of tensioning members 30 are oriented between and at a
right angle to the through-holes of the first pair 42 of tensioning
members 30.
[0043] As shown in FIGS. 4 and 5, the first embodiment of the
bowden cable transmission device 10' operatively connects to the
first 18 and second 20 bowden cables. As discussed above, the
second bowden cable 20 comprises a wire 26 and a sleeve 28 and is
attached at one end to the lumbar support member 14. At its
opposite second end 46, the sleeve 28 terminates at an end margin
and the wire 26 extends therefrom. The second end 46 of second
bowden cable 20 is connected to the first embodiment of the bowden
cable transmission device 10' by passing the wire 26 through the
through-holes 36 of both of the second pair 44 of tensioning
members 30. The sleeve 28 of the second bowden cable is inserted in
the counterbore (not shown) of the nearest one of the second pair
44 of tensioning members 30 until its end margin engages the
recessed annular surface of the counterbore which prevents it from
passing completely through the tensioning member. The free end of
the wire 26 extends into the counterbore 38 of the opposite of the
second pair 44 of tensioning members 30 and a retaining member 50
is attached thereto which then prevents the wire from passing back
through the through-hole 36 of said tensioning member.
[0044] The first bowden cable 18 is attached to the first
embodiment of the bowden cable transmission device 10' in a manner
similar to the second bowden cable 20 and, like the second bowden
cable, comprises a wire 52 and a sleeve 54. Like the second bowden
cable 20, the wire 52 of the first bowden cable passes through the
through-holes 36 of the first pair 42 of tensioning members 30.
[0045] In use, the first embodiment of the bowden cable
transmission device 10' is configured as shown in FIG. 4 when the
lumbar support member 14 is in a relaxed position. When desired,
the bowden cable actuator 16 can be triggered to increase the
tension of the wire 52 of the first bowden cable 18. As can be
appreciated by one skilled in the art, this increase in tension
causes the wire 52 of the first bowden cable to pass through the
through-holes 36 of the first pair 42 of tensioning members 30.
[0046] In use, the first embodiment of the bowden cable
transmission device 10' is configured as shown in FIG. 4 when the
lumbar support member 14 is in a relaxed position. When desired,
the bowden cable actuator 16 can be triggered to increase the
tension of the wire 52 of the first bowden cable 18. As can be
appreciated by one skilled in the art, this increase in tension
cause the wire 52 of the first bowden cable 18 to force each of the
first pair 42 of tensioning members 30 of the bowden cable
transmission device 10' toward the other. As should also be
appreciated, the configuration of the linking members 32 and the
pivot connections 34,40 causes the linking members to force each of
the second pair 44 of tensioning members 30 away from the other as
each of the first pair 42 of tensioning members 30 moves toward the
other. This in turn causes the wire of the second bowden cable 20
to be pulled further out from the end margin of its sleeve 28.
[0047] As the first pair 42 of tensioning members 30 move toward
each other, the second pair 44 of tensioning members 30 initially
move away from each more quickly than they do when the first
embodiment of the bowden cable transmission device 10' approaches
the configuration shown in FIG. 5, assuming the first pair of
tensioning members are brought toward each other at a constant
rate. This is due to the interconnecting configuration of the
linking members 32 and the tensioning members 30 and as such, the
movement of the wire 52 within the sleeve 54 of the first bowden
cable 18 is related to the movement of the wire 26 within the
sleeve 28 of the second bowden cable 20 in a non-proportional
manner. In order words, the movement of the wire 26 of the second
bowden cable 20 is not strictly in accordance with a constant ratio
with respect to the movement of the wire 52 of the first boden
cable 18.
[0048] As the second wire 26 moves, the lumbar support member 14 is
deflected. As the deflection increases, the tension in the second
wire 26 increase exponentially. Normally such an exponential
increase in tensile force would be realized by actuator 16.
However, due to the nonlinear conversion of movement between the
wire 52 of the first bowden cable 18 and the wire 26 of second
bowden cable 20 via the first embodiment of the bowden cable
transmission device 10', the tension in the first bowden cable
remains more consistent than it would otherwise. Additionally,
using the bowden cable transmission device 10', the total movement
of the wire 52 of the first bowden cable 18 is able to impair a
larger total movement of the wire 26 of the second bowden cable 20.
This reduces the amount of motion required by the actuator 16 to
fully deflect and relax the lumbar support member 14. Finally, the
transmission amplifier allows the use of components that are less
expensive and more compact.
[0049] Although now shown, the first embodiment of the bowden cable
transmission device 10' of the invention is preferably enclosed in
a housing. The housing is preferably shaped and configured to guide
the tensioning members 30 along their intended paths of motion so
as to keep the first 18 and second 20 bowden cables oriented at a
right angle relative to each other within the device. The housing
also acts to prevent foreign objects from interfering with the
moving parts of the bowden cable transmission device 10'. The
housing may also be formed integral with or attached to the
respective lumbar support member.
[0050] A second embodiment of the bowden cable transmission device
10'' is shown in FIGS. 6 and 7. The bowden cable transmission
device 10'' of the second embodiment differs from that of the first
embodiment in that its linkage assembly is formed as a single
monolithic piece of material, preferably molded plastic.
[0051] The second embodiment of the bowden cable transmission
device 10'' comprises four annual connection members 60 that are
connected by four linkage members 62. The linkage members are
joined to the connection members 60 via live hinges 64 that are
formed integrally therewith. The live hinges 64 allow to linkage
members 62 to generally pivot relative to the connection members
60. Each of the connection members 60 has a first hole 66 that
extends through its annular wall and a second larger hole 68 that
extends through its annular wall on the opposite side of the first
hole. The larger second hole 68 is configured to allow the sleeve
of a bowden cable to pass therethrough while the first hole 66 is
configured to allow only the wire of such a bowden cable to pass
therethrough. These first 66 and second 68 holes function in a
manner similar to the through-holes 36 and counterbores 38 of the
first embodiment, respectively.
[0052] In use, the second embodiment of the bowden cable
transmission device 10'' operatively connects to the first 18 and
second 20 bowden cables in a manner similar to the first
embodiment. Likewise, the second embodiment of the bowden cable
transmission device 10'' functions in a manner nearly identical to
that of the first embodiment as it moves back and forth between a
relaxed position as shown in FIG. 6 and a retracted position as
shown in FIG. 7. Furthermore, it should also be appreciated that
the second embodiment of the bowden cable transmission device 10''
is preferably contained within a housing similar to that of the
first embodiment.
[0053] A person skilled in the art will appreciate that, in
general, the first and second embodiments 10', 10'' of the bowden
cable transmission device do no necessarily require the second
bowden cable 20. Instead, it may also be sufficient to use only the
second wire 26 without the second sleeve 28, for example if the
bowden cable transmission device is directly attached or fixed to
the lumbar support member 14.
[0054] FIG. 8 shows a third embodiment of a bowden cable
transmission device 10''' of the present invention. In particular,
the transmission device 10''' is directly attached or fixed to the
back of a lumbar support member 14.
[0055] The transmission device 10''' comprises a substantially
longitudinal rotary member 82 which is rotatably supported around a
point of rotation 86 at the lumbar support member 14. The point of
rotation 86 is such that the distance in the longitudinal direction
of the rotary member 82 between the point of rotation 86 and the
upper longitudinal end of the rotary member 82 is at least slightly
larger than the distance between the point of rotation 86 and the
lower longitudinal end of the rotary member 82, i.e. the point of
rotation 86 is at least slightly eccentric in the longitudinal
direction of the rotary member 82. In addition, the rotary member
82 has a substantially elliptic shape and is plate-like or
disc-like. As can be taken from FIG. 8, the shape of the rotary
member 82 is further such that the width of the rotary member 82
slightly increases from the upper longitudinal end portion to the
lower longitudinal end portion. In general, it is recommendable for
the reasons discussed in the following in detail that the lower
longitudinal end portion has a larger width than the upper
longitudinal end portion.
[0056] Moreover, FIG. 8 shows a bowden cable 70 with a sleeve 72
and a wire 74 movable within the sleeve 72. The sleeve 72 of the
bowden cable 70 is supported at a holding member 76 or an opening
formed therein such that the sleeve 70 is held in place, while the
wire 74 runs through the opening of the holding member 76. The
holding member 76 may be formed integral with the back of the
lumbar support member 14.
[0057] The wire 74 of the bowden cable 70 runs along the periphery
or circumference of the rotary member 82. In particular, the wire
74 is wound around the rotary member 82 such that it extends along
one or more grooves (not shown) formed in the peripheral side
surface of the rotary member 82. As shown in FIG. 8, the wire 74
comes into contact with the upper longitudinal end portion of the
rotary member 82, extends along the peripheral side surface of the
rotary member 82, and then leaves the rotary member 82 at the lower
longitudinal end portion thereof. The grooves are formed such that
in operation the wire portion from the sleeve 72 to the rotary
member 82 does not come into contact with the wire portion from the
rotary member 82 to the connection point at the lumbar support
member 14 so as to avoid or at least reduce friction between both
wire portions.
[0058] The wire 74 is fixed at 84 to the rotary member 82. This can
be effected by a pin etc., as shown in FIG. 8, or by fixedly
clamping the wire 84 in the groove of the side surface of the
rotary member 82. In any case, the coupling between the wire 74 and
the rotary member 82 is such that adjustment or movement of the
wire 74 imparts rotation of the rotary member 82 around the point
of rotation 86. A stopper 80, which may also be formed integral
with the back of the lumbar support member 14, is provided for
restricting the rotation of the rotary member 82 in the
counter-clockwise direction. Although not shown, a similar stopper
may also be provided for restriction of the rotation of the rotary
member 82 in the clockwise direction.
[0059] A guiding member 78 is provided with guiding surfaces both
for the wire portion 74 running from the sleeve 72 of the bowden
cable 70 and the respective bowden cable actuator (not shown) to
the rotary member 82 and the wire portion 74 running from the
rotary member 82 substantially in the longitudinal direction of the
lumbar support member 14 so as to be fixed or connected thereto at
a respective connection point (not shown). As shown in FIG. 8, the
guiding surfaces should be curved so as to allow a smooth guidance
of the wire 74 with reduced friction at different positions of
rotation of the rotary member 82 without the risk of damaging the
wire 74 by sharp edges.
[0060] FIG. 9 shows the rotary member 82 in the case of an
unstressed state of the bowden cable 70 associated with a relaxed
position of the lumbar support member 14. Upon actuation of the
bowden cable actuator connected to the bowden cable 70, the wire 74
running through the sleeve 72 of the bowden cable 70 is tensioned,
and due to the connection between the wire 74 and the rotary member
82 the wire 74 exerts a traction force on the rotary member 82 so
as to rotate the rotary member 82 in the counter-clockwise
direction.
[0061] FIG. 10 shows the rotary member 82 in the case of a fully
tensioned state of the bowden cable 70 associated with a completely
flexed position of the lumbar support member 14.
[0062] As can be seen from FIG. 9 and FIG. 10, the longitudinal
shape of the rotary member 82 in combination with the eccentric
support of the rotary member 82 with respect to its longitudinal
direction and the increased width at the lower longitudinal end
portion of the rotary member 82 compared to the width at the upper
longitudinal end portion significantly allows to facilitate the
flexing of the lumbar support member 14. In particular, as can be
seen from a comparison of FIG. 10 with FIG. 9, a movement of the
wire portion between the sleeve 70 and the rotary member 82 is
converted into a larger movement of the wire portion between the
rotary member 82 and the connection point of the lumbar support
member 14. The lever arm defined between the point of rotation 86
and the (vertical) tangent at the rotary member 82 where the wire
portion between the sleeve 70 and the rotary member 82 comes into
contact with the rotary member 82 is smaller than the lever arm
defined between the point of rotation 86 and the tangent at the
rotary member 82 where the wire portion between the rotary member
82 and the connection point at the lumbar support member 14 leaves
the rotary member 82. Hence, a reduced traction force of the bowden
cable 70 is required for flexing the lumbar support member 14. The
torque at the point of rotation 86 and both lever arms defined with
respect to the point of rotation 86 are adapted to the required
load or curvature of the lumbar support member 14. In particular,
during operation of the transmission device 10''', both lever arms
are changed depending on the actuation of the bowden cable actuator
so as to achieve a constant torque around the point of rotation
86.
[0063] In conclusion, the transmission ratio effected by the
transmission device 101''' allows a larger curvature of the lumbar
support member 14 with less force to be exerted on the bowden cable
actuator.
[0064] Although the embodiment of FIGS. 8-10 has been described
with only one wire, it should be appreciated by a person skilled in
the art that this embodiment could well be realized with two or
more wires or wire portions as long they are coupled to the rotary
member 82 such that an adjustment or movement of the wire running
from the bowden cable actuator to the rotary member 82 imparts a
rotation of the rotary member 82 and thereby a respective
adjustment or movement of the wire running from the rotary member
82 to the connection point of the lumbar support member 14.
[0065] While the present invention has been described with
reference to specific embodiments, in light of the foregoing, it
should be understood that all matter contained in the above
description or shown in the accompanying drawings is intended to be
interpreted as illustrative and not in a limiting sense and that
various modifications and variations of the invention may be
constructed without departing from the scope of the invention
defined by the following claims. Furthermore, it should be
understood that when introducing elements of the present invention
in the claims or in the above description of the preferred
embodiment(s) of the invention, the terms "comprising,"
"including," and "having" are intended to be inclusive and mean
that there may be additional elements other than the listed
elements.
* * * * *