US20060226683A1

US20060226683A1 - Adjustable lumbar support with extensive configurability

Info

Publication number: US20060226683A1
Application number: US11/101,827
Authority: US
Inventors: Andrew Massara; Brandon Vogt; Rolf Schafer
Original assignee: Alfmeier Corp
Current assignee: Alfmeier Corp
Priority date: 2005-04-08
Filing date: 2005-04-08
Publication date: 2006-10-12

Abstract

An adjustable lumbar support for a seat having a seat frame is disclosed, the adjustable lumbar support including a floating support plate for providing an amount of lumbar support to a lumbar region of a seat, the support plate having a front surface and a rear surface, the floating support plate being attached to the seat frame via springs, the provided lumbar support defining an apex. A first actuator assembly and a second actuator assembly are each operatively connected to the floating support plate via respective first and second cables, the first and second cables being spaced from each other substantially vertically within the floating support plate, the first and second actuator assemblies for selectively actuating the respective cables to selectively move the apex substantially vertically and substantially horizontally forward and back relative to the seat frame. A secondary support plate may be provided, and may be hingedly and/or floatingly mounted. Adjustability may be achieved in terms of back and forth (horizontally), up and down (vertically) and by the vertical height of the lumbar support profile. Accordingly, in some aspects the present invention provides a “six-way” adjustable lumbar support.

Description

BACKGROUND OF INVENTION

1. Field of Invention
The present invention relates generally to seats, including vehicular seats. More particularly, the present invention relates to an adjustable lumbar support for a seat configurable to provide a wide range of lumbar support shapes and depths.
2. Description of the Related Art
It is well recognized that a person sitting in a seat for an extended time period may desire additional support to obtain greater seat comfort and/or alleviate seat discomfort. Vehicle operators, vehicle passengers, and people whose jobs require them to be seated for extended periods of time are typically chief among those individuals who seek such additional support. The support is typically desired to provide greater comfort in the lower or in the lumbar region of the back. As used herein, the term “seat” applies to a variety of seat structures, including chairs and vehicular seats.
The discomfort problem has been addressed in the prior art in several ways. A simple, although not complete, solution is to utilize a pillow placed low in the seat against the back thereof. By configuring the pillow into different shapes, a variation in lumbar support can be achieved. More permanent solutions to lumbar support problems have also been addressed, for example in U.S. Pat. No. 5,076,643 issued to A. Colasanti, et al., on Dec. 31, 1993; and U.S. Pat. No. 5,190,348 issued to A. Colasanti on Mar. 2, 1993.
Both of the devices described in the '643 and '348 patents are of complex construction and require substantial time and cost for fabrication and installation. The requirements for the installation of a mounting plate, as well as the inter-securement of the bladder and plate elements, are primary reasons for the high cost, complexity of construction and the need of substantial time for the manufacture and installation of each device.
Other devices are also known in the art. Among these other devices are those disclosed in U.S. Pat. No. 4,567,615 issued to H. Fanti on Feb. 4, 1986, and U.S. Pat. No. 6,056,360, issued on May 2, 2000, and assigned to the predecessor in interest of the assignee of the present application. The device of the '360 patent includes a lumbar support system comprising unitary and divided leaf members. This device proved to be complicated and costly to manufacture.
In addition to providing adjustment of the lumbar support in a horizontal direction, i.e. to increase or decrease the amount of support provided, it may be also desirable to provide adjustment of the lumbar support across a wider vertical range to accommodate a wide range of heights among seat occupants. For example, U.S. Pat. Nos. 5,474,358, 6,676,214, 6,652,028, and 6,338,530 disclose assemblies with vertically adjustable lumbar supports. In such devices the “bump” providing the support is slid up or down, for example along rails, to place the lumbar apex in a desired location. Accordingly, in placing the apex vertically, the profile of the “bump” is not changed, but the location is selectable vertically within a range. Such devices are sometimes called “four-way” lumbar support adjusters (i.e., adjustable forward and back, and up and down). However, such vertical movement of lumbar support parts within the seat, particularly while under load by an occupant, can damage the interior parts of the soft seat material, or the lumbar support itself. Also, the “bump” shape does not change, which may not provide comfortable support in all cases, even if the bump is optimally placed. Often, the bottom edge of the bump is fixed in a “back” position, thereby limiting adjustability and apex profile.
Other devices have been proposed wherein four-way adjustability is simulated, without actually having the vertical movement of the lumbar support mentioned above. For example, U.S. patent application Ser. No. 10/983,420, filed Nov. 9, 2004, and assigned to the Assignee of the present application, discloses a lumbar support adjuster including two overlapping support plates, both individually suspended and actuated. The support plates are arranged vertically, one above the other. U.S. Pat. No. 6,814,407 and 6,601,919 also disclose lumbar support adjusters, both including selective manipulation of adjacent sinuous coil spring members made from wire and used to provide support within a seat. Manipulation of such wires, in particular while under load by an occupant, can also cause damage to the soft, backside of the seat, even if no vertical motion is utilized.
Therefore, although various of the devices above have certain useful applications, the need still exists for a further improved lumbar support apparatus providing a range of adjustability, addressing at least one or more of the drawbacks of the above devices.

SUMMARY

It is therefore an objective of the present invention to provide a lumbar support apparatus that provides a comfortable range of lumbar support configurations, and that is not potentially destructive of other seating components.
According to certain aspects of the invention, an adjustable lumbar support for a seat having a seat frame is disclosed, the adjustable lumbar support including a laterally rigid floating support plate for providing support to a lumbar region of a seat, the support plate having a front surface and a rear surface, and a first support linkage and a second support linkage for supporting the floating support plate, the first support linkage being disposed laterally upward from the second support linkage along the floating support plate. Each support linkage is adapted for engaging the seat frame and has an effective length and at least one spring member disposed between the floating support plate and the seat frame, each support linkage supporting the floating support plate in a pivotal manner. An actuator selectively adjusts the effective length of either or both of the first and second support linkages, whereby an amount of lumbar support provided by the floating support plate is increased as the effective length of the first or second support linkage is decreased via the movement of the floating support plate relative to the support frame. Various options and modifications are possible.
For example, the first support linkage may be defined by a first cable member and first spring member, wherein the first spring member is adapted for engaging the seat frame, wherein the first cable member has a first end secured to the actuator and a second end secured to the first spring member, the first cable member sliding in a cable housing secured to the rear surface of the floating support plate. Also, the second support linkage may be defined by a second cable member and second spring member, wherein the second spring member is adapted for engaging the seat frame, wherein the second cable member has a first end secured to the actuator and a second end secured to the second spring member, the second cable member sliding in a cable housing secured to the rear surface of the floating support plate.
A secondary support plate may be mounted within the seat frame and pivotally connected to the floating support plate, the secondary support plate being floatingly positionable relative to the seat frame when the actuator is operated, thereby allowing for a larger amount of lumbar support. The secondary support plate may be located above the floating support plate within the seat frame, and the secondary support plate may be secured to the seat frame by spring members. The secondary support plate may be hingedly connected to the lower support plate.
The floating support plate may be molded in a seatback foam cushion attached to the seat frame, or the floating plate and a seatback foam cushion may be attached to the seat frame via a plurality of cooperating structures for attaching the floating support plate to the foam cushion.
The floating support plate may have a curved front surface, and it may be constructed of a substantially rigid material such that the floating support plate does not flex when loaded by an occupant.
The actuator may include a first actuator mechanism operatively associated with the first support linkage and a second actuator mechanism operatively associated with the second support linkage. The first and second actuator mechanisms may each include an electrical motor, and the electrical motors may be mounted to the seat frame.
The amount of lumbar support may define an apex, the apex being selectively movable substantially vertically and substantially horizontally forward and back relative to the seat frame by manipulation of the first and second actuating mechanisms. Also, the amount of lumbar support provided may have a vertical height, and the vertical height is selectively increasable or decreasable via the first and second actuating mechanisms.
According to other aspects of the invention, a seat assembly would include a seat frame and an adjustable lumbar support as described in various options and combinations above.
According to other aspects of the invention, an adjustable lumbar support for a seat having a seat frame is disclosed, the adjustable lumbar support including a floating support plate for providing support to a lumbar region of a seat, the support plate having a front surface and a rear surface, and a first support linkage and a second support linkage for supporting the floating support plate, the first support linkage being disposed laterally upward from the second support linkage along the floating support plate. Each support linkage is adapted for engaging the seat frame and has an effective length and at least one spring member disposed between the floating support plate and the seat frame, each support linkage supporting the floating support plate in a pivotal manner. A first actuator mechanism selectively adjusts the effective length of the first support linkage and a second actuator mechanism selectively adjusts the effective length of the second support linkage, whereby an amount of lumbar support provided by the floating support plate is increased as the effective length of the first or second support linkage is decreased via the movement of the floating support plate relative to the support frame. A secondary support plate is floatingly mounted within the seat frame and pivotally connected to the floating support plate, the secondary support plate being positionable relative to the seat frame when the actuator is operated, thereby allowing for an amount of lumbar support to be provided by the secondary support plate. Again, various options and modifications are possible.
For example, the first and second actuator mechanisms may each include respective electrical motors, and the first and second support linkages may each include respective Bowden cables. Also, the secondary support plate may be mounted to the seat frame via spring members vertically above the floating support plate within the seat frame. The floating support plate and the secondary support plate may define a width and a height greater than about one-third of the respective horizontal and vertical space between opposite side members of the seat frame.
According to other aspects of the invention, an adjustable lumbar support for a seat having a seat frame is disclosed, the adjustable lumbar support including a floating support plate for providing support to a lumbar region of a seat, the support plate having a front surface and a rear surface, the floating support plate being attached to the seat frame via springs, and a secondary support plate mounted within the seat frame substantially vertically adjacent to the floating support plate and pivotally connected to the floating support plate, the secondary support plate being attached to the seat frame via springs. A first actuator assembly and a second actuator assembly are each operatively connected to the floating support plate via respective first and second Bowden cables, the first and second Bowden cables being spaced from each other substantially vertically within the floating support plate, the first and second actuator assemblies for selectively actuating the respective Bowden cables to alter an amount of lumbar support provided by the floating support plate and secondary support plate. Again, various options and modifications are possible.
According to other aspects of the invention, an adjustable lumbar support for a seat having a seat frame is disclosed, the adjustable lumbar support including a laterally rigid floating support plate for providing an amount of lumbar support to a lumbar region of a seat, the support plate having a front surface and a rear surface, the floating support plate being attached to the seat frame via springs, the provided lumbar support defining an apex, and a first actuator assembly and a second actuator assembly each operatively connected to the floating support plate via respective first and second cables, the first and second cables being spaced from each other substantially vertically within the floating support plate. The first and second actuator assemblies selectively actuate the respective cables to selectively move the apex substantially vertically and substantially horizontally forward and back relative to the seat frame. As above, various options and modifications are possible.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and advantages of the present invention are apparent from the detailed description below and in combination with the drawings in which:
FIG. 1 is a perspective view of one embodiment of an adjustable lumbar support as mountable within a vehicle seat according to certain aspects of the invention and showing the adjustable lumbar support in a retracted position.
FIG. 2 is a side sectional view of the adjustable lumbar support taken along line 2-2 in FIG. 1.
FIG. 3A is a side sectional view as in FIG. 2, showing the adjustable lumbar support in a retracted position.
FIG. 3B is a side sectional view as in FIG. 2 showing the adjustable lumbar support in a first partially extended position.
FIG. 3C is a side sectional view as in FIG. 2 showing the adjustable lumbar support in a second partially extended position.
FIG. 3D is a side sectional view as in FIG. 2 showing the adjustable lumbar support in a fully extended position.
FIG. 4A is a top sectional view of the adjustable lumbar support taken along line 4-4 in FIG. 1, showing the adjustable lumbar support in the retracted position of FIG. 3A; and
FIG. 4B is a top sectional view of the adjustable lumbar support taken along line 4-4 in FIG. 1 showing the adjustable lumbar support in the partially extended position of FIG. 3B.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the figures. Each embodiment is presented for purposes of explaining the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield still a different embodiment. It is intended that the invention include these and other modifications and variations as come within the scope and spirit of the invention.
An adjustable lumbar support mechanism, constructed in accordance with the present invention, is illustrated generally as 10 in the figures. The adjustable lumbar support 10 provides a lumbar support mechanism that is adapted to be easily integrated into new or existing seat structures with minimal efforts and minimal costs. Moreover, in the preferred embodiment, the adjustable lumbar support 10 enables discrete regulation of the degree of seat support provided to an individual's lumbar spine area and, thereby, maximizes the individual's comfort while occupying a seat.
In its broadest aspects, the present invention incorporates a floating support plate 15 that “self centers” or “self aligns” offering firm yet compliant support and that “moves” with the occupant and is fully sprung, so as not to interfere with state of the art vibration insulation aspects of a seat, especially a vehicle seat. The floating support plate is adjustable by way of two separate support linkages 11 which may be operated separately or in tandem, and to different degrees, so as to achieve a wide range of amounts of support (depths, front to back) and a wide range of shapes of support (contours of the lumbar support). An optional secondary floating support plate 17 can be utilized to provide even wider support options.
As shown in FIG. 1, lumbar support 10 includes a support plate 15 mounted via support linkages 11 within a seat 12 having a seat frame including two side members 13 and cushioning 14. It should be understood that the lumbar support designs discussed herein could be used with various types and designs of seats, including but not limited to vehicle seats.
As shown, support plate 15 has a front surface 16 used to achieve lumbar support for a seat. Support plate 15 is supported by the two support linkages 11. Support linkages 11 are positioned with respect to support plate 15 so as to support the support plate in a pivotal manner. In this manner support plate 15 is self centering and self aligns itself with the occupant's back. Thus, support plate 15 is said to float relative to the seat frame.
As shown, each support linkage 11 is defined by a cable member 21 and first and second spring members 25 and 26 which engage the seat frame, as best seen in FIGS. 1, 4A an 4B. In this regard, the cable member 21 includes a first, terminal end 39 which is secured to first spring member 25, for example, by a stop, a clip, etc. Second spring member 26 is adapted to allow passage of the cable member 21 through the spring member 26 to an actuator mechanism, such as a motor 30, adapted for adjusting the amount of support provided by the floating support plate 15. It will be appreciated that the cable member 21 slides in a flexible guide tube 22, which serves as a cable housing adjacent floating support plate 15. Cable member 21 may comprise a Bowden cable including an internal wire 21 a and outer protective layer 21 b, if desired (see FIGS. 4A and 4B), or other alternative structures.
Each motor 30 may be actuated by a switch 31, such as a rocker switch that can provide alternate signals so as to be able to drive the motor in opposite directions as desired. Wiring 32 may connect motors 30 and switches 31 in various paths and forms. Alternatively, two separate switches or buttons, a rotatable dial, etc. could be provided to control each motor 30. Gearing may be provided within a gear mechanism 33 attached to the output of motor 30 to achieve a desired motion. Further, each motor 30 and related switch 31 could be replaced by a manual adjustment mechanism, such as is disclosed in U.S. patent application Ser. No. 10/983,420 for actuating cable member 21, if desired. Alternatively, a direct drive strap system could be utilized, thus eliminating the need for a remote driven cable.
Motors 30 are shown mounted, one each, on side members 13 of the frame of seat 12. However, such location is not required, and instead motors 30 could be mounted in other locations, such as to floating support plate 15 or secondary floating support plate 17. Motor mounting location may be dictated by factors such as available space, sound and vibration dampening issues, available cable member and wiring pathways, etc., and may vary by application.
If motors 30 are mounted on floating support plate 15, then the support linkages may be modified so as to extend only a few inches from motors 30 laterally to springs 25 and 26, in an in-line configuration. Long cable members 21 extending around the inside of the seat may then be avoided, and the support linkages are greatly simplified.
As shown, flexible guide tubes 22 are secured to rear surface 18 of floating support plate 15. In the preferred embodiment, at least one projection 35 extends from rear surface 18 of floating support plate 15 for each guide tube. Each projection 35 preferably includes a groove 38 for receiving the flexible guide tube 22 in a manner that substantially secures flexible guide tube 22 to floating support plate 15. In this manner, floating support plate 15 floats on the cable members 21, and cable members 21 (either in their entirety or just wire portions 21 a, as shown in FIGS. 4A and 4B) are allowed to slide freely through flexible guide tubes 22. Alternatively, conduits for cable members 21 could be integral with floating support plate 15. If cables 21 comprise Bowden cables, their outer protective layers 21 b may be removed between springs 25 and 26 (including the portion of cable 21 within tube 22).
The amount of lumbar support provided by the floating support plate 15 is determined by the effective length of the support linkages defined by the lengths of the cable members 21 disposed between the first and second spring members 25 and 26. In this regard, actuator mechanisms (in this case motors 30 and gear mechanisms 33), adapted to apply and release force, are fixed to the second end 40 of cable members 21. For instance, actuation of motors 30 via switches 31 causes moves the cable members 21 within the flexible guide tubes 22, either shortening or lengthening the effective length of the cables 21 between the first and second spring members 25 and 26. As can be seen in FIGS. 4A and 4B, as the effective length of the cable member 21 between the first and second spring members 25 and 26 is shortened, the amount of lumbar support provided by the floating support plate 15 is increased.
As shown, optional secondary support plate 17 may also be used to provide a greater range of lumbar support adjustability. Secondary support plate 17 is mounted to frame side members 13 via spring members 27 and is attached to floating support plate via a hinge 19. Hinge 19 may comprise any of various linking structures, such as a conventional hinge, a living hinge, or any other pivotal structure for attachment of plates 15 and 17. Therefore, secondary support plate 17 also floats within the seat frame via all of springs 25-27, as connected to and influenced directly by the positioning of floating support frame 15. However, as shown, secondary support plate 17 is not connected to its own adjustable support linkage, such as linkages 11 for floating support plate 15. As an option, such structures could be provided for secondary support plate if desired, but such is not required for all aspects of the invention. In particular, if secondary support plate 17 is located vertically above floating support plate 15, due to typical human back contouring, an adjustable linkage may not be needed or comfortable in such upper back location.
As shown, floating support plate 15 and secondary support plate 17 may be made large enough to take up a substantial amount of space horizontally and vertically between frame side members 13. For example, plates 15 and 17 may take up more than about one-third of such lateral space. Also, plates 15 and 17 together take up a substantial amount of space top to bottom between frame side members 13, again preferably more than about one-third of the vertical space. Such relative dimensioning, while optional, can assist in providing solid and comfortable support across a wide area.
Plates 15 and 17 are preferably fabricated from a substantially rigid material such as plastic. In particular, lateral rigidity provides the benefit in some applications of firm support across the back, avoiding bending and wrap associated with coiled wire support structures. Floating support plate 15 could alternatively be more flexible to offer more resilient support in certain applications. Of course, those skilled in the art will recognize that the curved support member could be fabricated from other rigid, preferably lightweight, materials, such as composites or metals. Also, while the figures illustrate a plurality of cutouts disposed in the upper surface 16 of floating support plate 15 and through plate 17, which are provided for weight reduction, it will be appreciated that the upper surface 16 could be substantially solid and could have other shapes and cross sections.
Use of relatively rigid plates 15 and 17 mounted via spring members 25-27 effectively separates the various movements and functions performed during loading and adjustment of seat 12 between parts. For example, relatively rigid plates 15 and 17 provide a firm and relatively rigid lumbar support surface, while the spring members 25-27 and cables 21 allow the plates to float and flex relative to the frame. This separation of function reduces the likelihood of damage to the rear (usually foamed or otherwise softer) surfaces of the seatback as compared to prior art sinuous wire structures, which extend and retract laterally across their entire lengths during use, thereby pinching or stretching the seatback continuously at the contact points. Further, by providing adjustability of lumbar support over a broad vertical range without requiring the lumbar support to be driven vertically up and down as in some prior art devices, pinching and stretching in vertical directions are also minimized.
Further, although not shown herein, the floating plate can be fixed to the foam directly. Thus, cooperating structures of various types, such as notches and tabs, could be provided on plates and 15 and 17 and the seatback for attachment, or the plates could be molded into the seatback foam cushion.
As shown in FIGS. 3A-3D, the disclosed structures provide for a great range of adjustment of lumbar support. For example, FIG. 3A shows the “full off” position, with no additional amount of lumbar support. Line A in FIG. 3A represents roughly the lumbar support provided in the full off position.
FIG. 3B shows the lumbar support amount provided by adjusting the first (lower) support linkage 11 so as to shorten lower cable 21 and draw floating support plate 15 forward. Line B in FIG. 3B shows the lumbar support amount provided in this position, and Line A in FIG. 3B shows the reference full off position of FIG. 3A. As shown, with only the lower support linkage 11 activated, only the bottom part of floating plate 15 moves forward, including in particular the lower edge of plate 15. In fact, the upper portion of floating plate 15 and the lower portion of plate 17 may even move backward, as shown. Even so, plate 17 and the various springs function to maintain the top of plate 15 without substantial movement when only lower support linkage is actuated, as in FIG. 3B. The position of plates 15 and 17 may be a comfortable position for a small individual, or may comprise a first step in positioning support 10. The inclusion of plate 17 in the design, when used by any individual, may thus provide a more continuous lumbar support profile extending toward the upper back than if plate 17 were not present. Thus, while the apex X of the lumbar support is fairly low in FIG. 3B, the shape of the support traveling upward has a somewhat gradual curvature. However, it should be kept in mind that use of secondary support plate 17, or use of the plate as connected or hinged to floating support plate 15, is not required for all aspects of the invention.
FIG. 3C shows the lumbar support amount obtained when adjusting the first (lower) support linkage 11 and the second (upper) support linkage 11 so as to shorten both cables 21 and draw floating support plate 15 forward at both cable heights. Line C in FIG. 3C shows the lumbar support amount provided in this position, and Line A in FIG. 3C shows the reference full off position of FIG. 3A. A comparison of the positions of lines A-C in FIGS. 3A-3C shows the different amounts of lumbar support achievable. It should be kept in mind that each support linkage can be adjusted individually and to greater or lesser extents so as to reach various positions between lines A and C or further, as is deemed comfortable. As shown by line C, it is possible to thus obtain forward extending lumbar support profile extending upward for a substantial distance from the bottom of plate 15 (i.e., all along plate 15 and more than halfway to the top of plate 17, when configured as shown herein), with a much higher apex X. Taller and/or heavier individuals could find this orientation to provide more comfortable support as compared to a vertically smaller lumbar support located with an apex either in a lower back position or in a position driven higher toward the mid-back. Such a user might, though, first adjust plates 15 and 17 to the position shown in FIG. 3B by adjusting only lower support linkage 11 until comfortable lower back support is achieved, and then adjust upper support linkage 11 until a comfortable position akin to that in FIG. 3C is achieved. Also, both the upper and lower linkages could simply by “tinkered with” until a comfortable position is found. Accordingly, use of two separate linkages 11 within a single plate 15 does provide a wider range of adjustability than only one linkage, even if upper plate 17 were not used. Further, use of two linkages 11 and two plates 15 and 17 provides an even greater range of adjustability, particularly suited for providing additional comfortable seating for taller and/or heavier drivers heretofore underserved by lumbar support devices.
FIG. 3D shows along line D a lumbar support amount possible using only upper linkage 11, with an apex at X. Again, certain individuals may benefit from such a profile, or it may simply be step in the adjustment process for others.
Thus, the structures described above can provide an improved alterative to conventional “four-way” adjustability. In fact, it can be said that the above structures can provide effectively “six-way” adjustability. Namely, the lumbar support apex may be adjusted forward and back, up and down, and the profile of the lumbar support may be adjusted in vertical length. Thus, a broader spectrum of positioning is possible, leading to a more people finding a seat equipped with structures according to the present invention to be a comfortable seat.
While preferred embodiments of the invention have been shown and described, those skilled in the art will recognize that other changes and modifications may be made to the foregoing embodiments without departing from the scope and spirit of the invention. For example, specific shapes of various elements of the illustrated embodiments may be altered to suit particular applications. It is intended to claim all such changes and modifications as fall within the scope of the appended claims and their equivalents. Moreover, references herein to “top,” “lower,” “bottom,” “upward,” “downward,” “descending,” “ascending,” and “side” structures, elements and geometries and the like are intended solely for purposes of providing an enabling disclosure and in no way suggest limitations regarding the operative orientation of the exemplary embodiments or any components thereof.

Claims

1. An adjustable lumbar support for a seat having a seat frame, the adjustable lumbar support comprising:

a laterally rigid floating support plate for providing support to a lumbar region of a seat, the support plate having a front surface and a rear surface;

a first support linkage and a second support linkage for supporting the floating support plate, the first support linkage being disposed laterally upward from the second support linkage along the floating support plate, wherein each support linkage is adapted for engaging the seat frame and has an effective length and at least one spring member disposed between the floating support plate and the seat frame, each support linkage supporting the floating support plate in a pivotal manner; and

an actuator for selectively adjusting the effective length of either or both of the first and second support linkages, whereby an amount of lumbar support provided by the floating support plate is increased as the effective length of the first or second support linkage is decreased via the movement of the floating support plate relative to the support frame.

2. The adjustable lumbar support of claim 1, wherein the first support linkage is defined by a first cable member and first spring member, wherein the first spring member is adapted for engaging the seat frame, wherein the first cable member has a first end secured to the actuator and a second end secured to the first spring member, the first cable member sliding in a cable housing secured to the rear surface of the floating support plate.

3. The adjustable lumbar support of claim 2, wherein the second support linkage is defined by a second cable member and second spring member, wherein the second spring member is adapted for engaging the seat frame, wherein the second cable member has a first end secured to the actuator and a second end secured to the second spring member, the second cable member sliding in a cable housing secured to the rear surface of the floating support plate.

4. The adjustable lumbar support of claim 1, further including a secondary support plate mounted within the seat frame and pivotally connected to the floating support plate, the secondary support plate being floatingly positionable relative to the seat frame when the actuator is operated, thereby allowing for a larger amount of lumbar support.

5. The adjustable lumbar support of claim 4, wherein the secondary support plate is located above the floating support plate within the seat frame.

6. The adjustable lumbar support of claim 4, wherein the secondary support plate is secured to the seat frame by spring members.

7. The adjustable lumbar support of claim 4, wherein the secondary support plate is hingedly connected to the lower support plate.

8. The adjustable lumbar support of claim 1, wherein the floating support plate is molded in a seatback foam cushion attached to the seat frame.

9. The adjustable lumbar support of claim 1, wherein the floating support plate and a seatback foam cushion attached to the seat frame include a plurality of cooperating structures for attaching the floating support plate to the foam cushion.

10. The adjustable lumbar support of claim 1, wherein the floating support plate has a curved front surface.

11. The adjustable lumbar support of claim 1, wherein the floating support plate is constructed of a substantially rigid material such that the floating support plate does not flex when loaded by an occupant.

12. The adjustable lumbar support of claim 1, wherein the actuator includes a first actuator mechanism operatively associated with the first support linkage and a second actuator mechanism operatively associated with the second support linkage.

13. The adjustable lumbar support of claim 12, wherein the first and second actuator mechanisms each include an electrical motor.

14. The adjustable lumbar support of claim 13, wherein the electrical motors are mounted to the seat frame.

15. The adjustable lumbar support of claim 1, wherein the amount of lumbar support defines an apex, the apex being selectively movable substantially vertically and substantially horizontally forward and back relative to the seat frame by manipulation of the first and second actuating mechanisms.

16. The adjustable lumbar support of claim 1, wherein the amount of lumbar support provided has a vertical height, and the vertical height is selectively increasable or decreasable via the first and second actuating mechanisms.

17. A seat assembly including a seat frame and an adjustable lumbar support as in claim 1.

18. An adjustable lumbar support for a seat having a seat frame, the adjustable lumbar support comprising:

a floating support plate for providing support to a lumbar region of a seat, the support plate having a front surface and a rear surface;

a first support linkage and a second support linkage for supporting the floating support plate, the first support linkage being disposed laterally upward from the second support linkage along the floating support plate, wherein each support linkage is adapted for engaging the seat frame and has an effective length and at least one spring member disposed between the floating support plate and the seat frame, each support linkage supporting the floating support plate in a pivotal manner;

a first actuator mechanism for selectively adjusting the effective length of the first support linkage and a second actuator mechanism for selectively adjusting the effective length of the second support linkage, whereby an amount of lumbar support provided by the floating support plate is increased as the effective length of the first or second support linkage is decreased via the movement of the floating support plate relative to the support frame; and

a secondary support plate floatingly mounted within the seat frame and pivotally connected to the floating support plate, the secondary support plate being positionable relative to the seat frame when the actuator is operated, thereby allowing for an amount of lumbar support to be provided by the secondary support plate.

19. The adjustable lumbar support of claim 18, wherein the first and second actuator mechanisms each include respective electrical motors, and the first and second support linkages each include respective Bowden cables.

20. The adjustable lumbar support of claim 18, wherein the secondary support plate is mounted to the seat frame via spring members vertically above the floating support plate within the seat frame.

21. The adjustable lumbar support of claim 18, wherein the floating support plate and the secondary support plate define a width and a height greater than about one-third of the respective horizontal and vertical space between opposite side members of the seat frame.

22. The adjustable lumbar support of claim 18, wherein the floating support plate and the secondary support plate provide lumbar support defining an apex, the apex being selectively movable substantially vertically and horizontally forward and back relative to the seat frame by manipulation of the first and second actuating mechanisms.

23. The adjustable lumbar support of claim 18, wherein the amount of lumbar support provided has a vertical height, and the vertical height is selectively increasable or decreasable via the first and second actuating mechanisms.

24. A seat assembly including a seat frame and an adjustable lumbar support as in claim 18.

25. An adjustable lumbar support for a seat having a seat frame, the adjustable lumbar support comprising:

a floating support plate for providing support to a lumbar region of a seat, the support plate having a front surface and a rear surface, the floating support plate being attached to the seat frame via springs;

a secondary support plate mounted within the seat frame substantially vertically adjacent to the floating support plate and pivotally connected to the floating support plate, the secondary support plate being attached to the seat frame via springs; and

a first actuator assembly and a second actuator assembly each operatively connected to the floating support plate via respective first and second Bowden cables, the first and second Bowden cables being spaced from each other substantially vertically within the floating support plate, the first and second actuator assemblies for selectively actuating the respective Bowden cables to alter an amount of lumbar support provided by the floating support plate and secondary support plate.

26. The adjustable lumbar support of claim 25, wherein the floating support plate and the secondary support plate provide lumbar support defining an apex, the apex being selectively movable substantially vertically and substantially horizontally forward and back relative to the seat frame by manipulation of the first and second actuating mechanisms.

27. The adjustable lumbar support of claim 25, wherein the amount of lumbar support provided has a vertical height, and the vertical height is selectively increasable or decreasable via the first and second actuating mechanisms.

28. A seat assembly including a seat frame and an adjustable lumbar support as in claim 25.

29. An adjustable lumbar support for a seat having a seat frame, the adjustable lumbar support comprising:

a laterally rigid floating support plate for providing an amount of lumbar support to a lumbar region of a seat, the support plate having a front surface and a rear surface, the floating support plate being attached to the seat frame via springs, the provided lumbar support defining an apex; and

a first actuator assembly and a second actuator assembly each operatively connected to the floating support plate via respective first and second cables, the first and second cables being spaced from each other substantially vertically within the floating support plate, the first and second actuator assemblies for selectively actuating the respective cables to selectively move the apex substantially vertically and substantially horizontally forward and back relative to the seat frame.

30. The adjustable lumbar support of claim 29, wherein the amount of lumbar support provided has a vertical height, and the vertical height is selectively increasable or decreasable via the first and second actuating mechanisms.

31. The adjustable lumbar support of claim 29, further including a secondary support plate mounted within the seat frame substantially vertically adjacent to the floating support plate and pivotally connected to the floating support plate, the secondary support plate being attached to the seat frame via springs.

32. A seat assembly including a seat frame and an adjustable lumbar support as in claim 29.