Abstract:
A back support for use in seats such as automobile seats or office chairs, includes a flexible support member mounted to the seatback. The shape of the flexible support member changes responsively to a load imposed by a person&#39;s back, and may also be changed by an actuator system. Noise, galling, wear and rough movement between moving parts of the flexible back support are reduced by selectively controlling the properties of the surfaces of the flexible support member, the mounting structures, or both. In particular, at least a portion of these surfaces are treated to provide friction surfaces, protection surfaces or both are used. Any combination of devices can be used to treat the surfaces, including tapes, lubricants, extrusions, sleeves, coatings, films, and self-lubricated material sections. These treatment options are especially useful at interface locations, wear surfaces, and contact surfaces, and a substantial portion of the flexible support member or the mounting structures may remain free of these treatments.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation of U.S. application Ser. No. 10/113,429, filed on Mar. 29, 2002 which claims priority under 35 U.S.C. Sec. 119(e) to provisional application 60/279,786 filed Mar. 29, 2001 and to provisional application 60/312,869 filed Aug. 16, 2001. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The present invention relates to back supports and more particularly to back supports used in seatbacks.  
           [0005]    2. Description of Related Art  
           [0006]    A variety of seat back support devices provide added support and comfort to a person&#39;s back. These devices are especially common in vehicle seats or office chairs as lumbar supports. Such devices are described in U.S. Pat. Nos. 5,518,294; 6,296,308 B1; 5,397,164; 6,036,265; 6,254,187; 6,227,618; 6,158,300; 6,152,532; 6,050,641; 6,036,265; 6,007,151; 5,816,653; 5,681,005; and 5,609,394, the teachings of which are hereby expressly incorporated by reference herein. For all such devices, reducing noise, wear and promoting smooth functional interaction of the moving parts of such back supports is a continuing need.  
         SUMMARY OF THE INVENTION  
         [0007]    This lumbar support invention provides a unitary flexible support member formed from a sheet of material. The support member arches outwardly to support a person&#39;s back. The support member preferably has a central body portion with a longitudinal axis and opposite ends at each end of the axis. Typically, a number of support fingers extend outwardly from the central body portion in a generally horizontal direction. A means for arching the support member is attached to the support member to arch the support member outwardly to support a person&#39;s back.  
           [0008]    The flexible support member must be mounted in the frame of a seat. One conventional mounting method is with guide wires which are usually vertical and run through mounting slots in either longitudinal end of the flexible support member. Another conventional mounting method is with horizontal bars that are pivotably, rotatably or slidingly mounted to either longitudinal end of the flexible support member. According to the present invention, either the support member, bars, wires or like structure upon which it is mounted, or both, have their coefficient of friction reduced to quiet, smooth and reduce wear in their interaction.  
           [0009]    Reducing the coefficient of friction is achieved by selectively coating portions of the assembly with a low friction material, surface smoothing, such as by a vibratory technique, by interposing friction reducing elements such as plastic members or tape, or by lubricating, such as with oils.  
           [0010]    The means for arching the support member, for example a traction cable, may also benefit from reducing the coefficient of friction between it and the flexible support member.  
           [0011]    The support fingers and front of the flexible support surface may also be surface smoothed, such as by a vibratory technique. This reduces wear on the seat cushions. The result is a relatively low cost improved support member for use in a back support device.  
           [0012]    Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a front perspective view of an embodiment of the inventive back support.  
         [0014]    [0014]FIG. 2 is a perspective view of another embodiment of the inventive back support.  
         [0015]    [0015]FIG. 3 is an elevational view of another back support embodiment.  
         [0016]    [0016]FIG. 4 is an elevational view of yet another back support embodiment.  
         [0017]    [0017]FIG. 5 is a perspective view of another embodiment showing a back support attached to a seat base frame.  
         [0018]    [0018]FIG. 6 is an elevational view of the configuration illustrated in FIGS. 6 b - 6   c.    
         [0019]    [0019]FIGS. 6 b - 6   c  are side views showing an alternative approach for actuating a back support.  
         [0020]    [0020]FIGS. 7 a - c  is a side view showing another alternative approach to actuation.  
         [0021]    [0021]FIG. 8 illustrates a perspective view of a seat back insert for facilitating back support actuation.  
         [0022]    [0022]FIGS. 9 a - c  illustrate an embodiment including a translatable member for providing adjustable support.  
         [0023]    [0023]FIG. 10 illustrates another embodiment including plural tensionable members for local support. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    The subject of the invention is an improvement to lumbar supports, such as described in U.S. Pat. Nos. 5,518,294; 6,296,308; 5,397,164; 6,036,265; 6,254,187; 6,227,618; 6,158,300; 6,152,532; 6,050,641; 6,036,265; 6,007,151; 5,816,653; 5,681,005; and 5,609,394, which are hereby incorporated by reference for all purposes.  
         [0025]    Referring to the accompanying drawings in which like reference numbers indicate like elements,  
         [0026]    [0026]FIG. 1 is a front perspective view of one preferred embodiment  10  of a back support designed in accordance with this invention. A support member  12  is mounted in a conventional seatback upon a first bar  14  (e.g., a wire or like member, which is generally vertically or horizontally oriented) at a first longitudinal end  16  of the support member  12 . An optional second bar  18  is positioned near the second longitudinal end  20  of single-piece support member  12  such that the mounting portion near the second longitudinal end  20  provides a pivotal and movable mount upon or about bar  18 . In the embodiment depicted in FIG. 1, Bars  14  and  18  are preferably horizontally disposed within a seatback frame as generally shown in FIG. 2. The details of the mounting and movement of the single-piece support member  12  upon bars  14  and  18  are provided in U.S. Pat. No. 5,518,294.  
         [0027]    Support member  12  includes a central body  22  that may further include longitudinal strips  24  and  26 . Transverse strips  28  may also be provided between longitudinal strips  24  and  26  to provide greater comfort to a user and to provide more integrity and stability to support member  12 . In one embodiment the support member is a single piece. In another embodiment, the support member  12  is preferably formed of a single stamping of an alloy metal known as Martinsite®. The lightweight and durable nature of support member  12  may be further enhanced by providing transverse strips  28  between longitudinal strips  24  and  26  rather than providing a solid member as central body  22 . As discussed in further detail, rather than powder coating or otherwise coating the entire support member  12  (which will typically be a stamping), improved results are possible by selectively treating the stamping with a coating  30  to impart a protective surface, a low friction surface or both over only a portion of the member  12 .  
         [0028]    Extending outward from central body  22  are support fingers  32 . Support fingers  32  may be coplanar with or angled relative to a plane defined by central body  22 . The angle of support fingers  32  may be selected to yield greater lateral support for a user and to enhance the comfort provided by the inventive back support. The peripheral edges  34  of support fingers  32  may be flat or bent back slightly relative to the forward projection of the support fingers  32 . Preferably the edges  34  (or optionally other edges of the member  12 ) are surface smoothed to avoid sharp edges, burrs or the like. One preferred approach is to vibratory smooth the edges such as by vibratory burnishing.  
         [0029]    It is to be understood that the references within this description to the top or bottom of the support member are relative to the mounting of the illustrated preferred embodiment. The items described may be inverted and still fall within the present invention.  
         [0030]    First plate  36  includes suitable mounting structure (e.g., clamping members  38  and  40 , other gripping members, or the like) for mounting the first longitudinal end  16  of support member  12  on bar  14 . When employed, clamping members  38  and  40  provide an easy installation of the support member  12  because clamping members  38  and  40  effectively “snap on” bar  14  as the support member is moved generally upward against bar  14 . The mounting provided by clamping members  38  and  40  enables efficient assembly requiring a minimum amount of tools and a minimum amount of parts.  
         [0031]    The actuation mechanism and other operational features of the present device can be gleaned from U.S. Pat. No. 5,518,294, which is hereby incorporated by reference. In one embodiment, as shown in FIG. 1, the two ends of the lumbar support member are supported by two bars (or wires) that are part of the seat back. There is relative motion between the wires and the stamped element, primarily rotation at one end, and sliding at the other end. In order to prevent noise and galling of the wires, a lubricating material or a suitable plastic material sleeve or coating is used at the interface between the wires and the member  12 . For instance, the material used may be a powder coat, or a liquid coating applied by a spray process, wherein the coating is baked to dry out the solvents and cure the resin. The same process may be applied to either guide wires or mounting bars instead of the flexible support member or in addition to it.  
         [0032]    In another embodiment, at least a portion of the wire or bar is treated to have a low friction surface. For example, the wire may be treated by extruding the wire with a low friction plastic. For instance, the wire might be treated by cross head extruding it with a plastic. Alternatively, the wire may be treated by placing or pressing an extruded plastic tube over said wire.  
         [0033]    By way of illustration of the techniques for treating the member  12 , the following are disclosed. In one example, a suitable tape is fabricated of a layer of low friction plastic (e.g., ultra high molecular weight polyethylene (UHMWPE), ultrahigh density polyethylene, or the low friction materials disclosed elsewhere herein) with a suitable adhesive (e.g., an acrylic pressure sensitive adhesive). The tape is applied to the member at the areas that are in contact with the seat back wire or where there is contemplated to be sliding contact between two parts under pressure as for example the Bowden traction cable depicted in FIG. 44. As mentioned a number of materials are suitable for the function described above. In general, the materials will exhibit a relatively high sliding abrasion resistance, a relatively high notched impact resistance, a relatively low coefficient of friction for on-stick, self lubricated surfaces, relatively good toughness and ductility from −452° to +194° F., relatively high noise reduction and shock absorption, and relatively good dimensional stability. In another embodiment, in lieu of or in combination with a tape, a lubricant (e.g., a grease or an oil) is employed over at least a portion of the member. By way of illustration, one suitable lubricant is or has the characteristics of Krytox® oil (available from DuPont). Such characteristics are summarized in Table A, which are typical properties, not specifications, based on historical production performance and viscosity may vary within ±10%. For example, P.F.P.E. (k) (Krytox) oil with a viscosity index of about 124 and a useful temperature range of about −60° F. to +355° F. would provide the necessary lubricity to pass our screening.  
                                                     TABLE A                       Typical Properties of Krytox ® General Purpose Oils and Greases                                GPL Oil Grades   100   101   102   103   104   105   106   107       GPL Std Grease Grades (GG)   200   201   202   203   204   205   206   207       GPL Extreme Pressure GG   210   211   212   —   214   215   216   217       GPL Anti Corrosion Grease GG   220   221   222   223   224   225   226   227       ISO Grade of Oil - Approx.   5   7   15   32   68   150   220   450       Estimated Useful Range - Based       on pour point and where       evaporation is approximately 10%       ° C.   &lt;−70/66   &lt;−70/104   −63/132   −60/154   −51/179   −36/204   −36/260   −30/288       ° F.   &lt;−94/150   &lt;−94/220   −81/270   −76/310   −60/355   −33/400   −33/500   −22/550       Oil Viscosity, cST/ASTM D445        20° C. (68° F.)   7   16   36   80   180   550   810   1600        40° C. (104° F.)   4   8   15   30   60   160   240   440       100° C. (212° F.)   —   2   3   5   9   18   25   42       204° C. (400° F.)   —   —   —   —   —   3   3.9   6       260° C. (500° F.)   —   —   —   —   —   —   2.1   3       Oil Viscosity Index/D2270   —   —   59   121   124   134   134   144       Oil Pour Point/D97       ° C.   &lt;−70   &lt;−70   −63   −60   −51   −36   −36   −30       ° F.   &lt;−94   &lt;−94   −81   −76   −60   −33   −33   −22       Oil Density, g/ml        0° C. (32° F.)   1.87   1.89   1.91   1.92   1.93   1.94   1.95   1.95       100° C. (212° F.)   1.67   1.70   1.72   1.74   1.75   1.76   1.77   1.78       Maximum Oil Volatility % in       22 hrs/D972 (Modified)       @66° C. (150° F.)   11   2   2   1   1   1   &lt;1   —       @121° C. (250° F.)   87   35   20   7   3   2   1   —       @204° C. (400° F.)   —   —   —   —   —   10   &lt;5   &lt;1       Oil Separation From       Grease/FTMS 7918 321.1       Wt. Loss, % 30 hrs       @99° C. (210° F.)   18   9   7   5   4   4   3   3       @204° C. (400° F.)   —   —   —   —   —   —   11   10       Oil, 4-Ball Wear Test,       (20 kg/107° C.)/ASTM D4172,       (225° F.)/1200 rpm/60 min,       results provided with avg. std. deviation       West Scar. Mm (±0.01)   0.4   0.4   0.4   0.3   0.4   0.3   0.3   0.4       Friction Coefficient, (±0.003)   0.08   0.07   0.07   0.08   0.07   0.07   0.08   0.08       Oil, Falex Pin/V-Block       Load Carrying/ASTM D3233       Ability, Max Load, lbs (gauge)   1375   1400   1250   1555   1450   &gt;4500   &gt;4500   &gt;4500       Torque at Max Load, in-lb   30   31   32   35   32   56   65   65                  
 
         [0034]    In yet another illustrative embodiment, a laminated tape is employed having performance characteristics of the tapes disclosed in Table B. For example a plastic/metal foil tape might be employed, having an adhesive for bonding on one of its surfaces. By way of illustration, a tape may be used having on the order of about 0.002 inch thick metal (e.g. aluminum), which has a pressure sensitive adhesive on one surface, and a plastic (e.g., PTFE or Teflon®) layer on the order of about 0.001 inch thick on the other metal surface. It is believed that this provides sufficient lubricity and toughness to withstand the sliding contact with the seat back wire. Of course, as mentioned above, the above techniques can be used in lieu of or in combination with treating the bars.  
                                                     TABLE B                       Pressure Sensitive Tapes                                PRODUCT:   TF12-53PS       CONSTRUCTION:   Backing: 0.001″ FEP Teflon ®/           0.002″ Aluminum Foil Adhesive:           0.001″ Acrylic Pressure Sensitive Adhesive       APPLICATION:   High slip/low coefficient of friction qualities           of Teflon ® combined with           excellent formable characteristics of foil           and long term acrylic pressure           sensitive adhesive. Protective           tape &amp; sheeting in plating room,           chute liners, hoppers, etc.                        PROPERTY   VALUE   TEST METHOD                       Thickness:   0.004 inch +/− 10%   ASTM-D-3652           Peel Strength:   32 oz./inch of width   ASTM-D-1000,                   15 minute dwell           Breaking Strength:   13 lbs./inch of width   ASTM-D-1000           Elongation at Break:   5%   ASTM-D-1000                Color: Silver           Shelf Life: 1 year when stored under conditions           of 70 degrees F. (21 degrees C.) and 50% R.H.                      
 
         [0035]    Table C illustrates a range of characteristics for suitable UHMWPE materials.  
                                                                       TABLE C                       UHMW Tape                                PRODUCT:   Ultra high molecular weight polyethylene film with an aggressive pressure           sensitive adhesive. 50 DK silicone release liner available.       APPLICATIONS:   UHMW has a low coefficient of friction, therefore offers excellent abrasion           resistance. Perfect for sound dampening applications in the appliance and           transportation industries and for conveyance applications where a slick,           wear resistant surface is needed. Self-wound and linered versions available           in both logs and slit rolls.                    PROPERTY   VALUE   TEST METHOD                    Tape Types   150-3    150-5    150-10               Film Thickness:   0.003″   0.005″   0.010″   (+/−10%)   ASTM-D-3652       Adhesive Thickness:   0.0018″   0.0018″   0.0018″   (+/−10%)   ASTM-D-3652       Total Thickness:   0.0048″   0.0068″   0.0118″   (+/−10%)   ASTM-D-3652       Liner Thickness:   0.0032″   0.0032″   0.0032″   (+/−10%)   ASTM-D-3652       Adhesion to Steel:   35 oz./inch   40 oz./inch   28 oz./inch       ASTM-D-1000                           (15 min. dwell)       Breaking Strength:   18#   30#   60#   lbs/in of width   ASTM-D-882       Elongation:   270%   300%   450%       ASTM-D-882       Taber Abrasion:   &lt;2.0 mg   &lt;2.0 mg   &lt;2.0 mg   mg mass loss   SAE-J-1847       Dry Dynamic       0.11-0.25   0.11-0.25   0.11-0.25   ASTM-D-1894       Coefficient of Friction:            Shelf Life: 1 year when stored under conditions of 70 degrees F. (21 degrees C.) and 50% R.H.                  
 
         [0036]    [0036]FIG. 2 illustrates an alterative support member  42  for mounting on vertically oriented bars or wires, for which the present invention may have like utility. In this regard, the inventive aspects described herein find utility with support members of the type disclosed in other seat back devices including but not limited to those described in U.S. Pat. No. 6,158,300 (Klingler); U.S. Pat. No. 5,397,164 (Schuster); U.S. Pat. No. 6,296,308 B1 (Costentino); U.S. Pat. No. 6,050,641 (Benson); U.S. Pat. No. 6,152,532 (Cosentino); U.S. Pat. No. 6,036,265 (Cosentino); U.S. Pat. No. 6,007,151 (Benson); U.S. Pat. No. 5,816,653 (Benson), the teachings of which are hereby expressly incorporated by reference herein.  
         [0037]    The exact materials of Tables A-C (hereby incorporated by reference) need not be employed to be within the scope of the present invention. Other coatings might include powder coatings (e.g. graphite powder coatings), or the like. Further, some or all of the coating locations shown in FIG. 1 may be omitted (e.g. over the strips  26 , 28  the fingers or elsewhere), or coatings may be employed elsewhere over the member surface or over all of it. However, it is preferred that materials employed exhibit relatively comparable performance in the relevant properties.  
         [0038]    Though it is appreciated that the present invention also contemplate that an entire part is coated, overall, it is preferred that a substantial portion of the member  12  be free of a coating (which encompasses traditional coatings as well as tapes, films or the like) in accordance with the present invention, and that any such coatings employed are selectively employed over wear or contact surfaces. In one preferred embodiment, no more than about 50% of the member surface is coated. In other embodiment, no more than about 30% of the member surface is coated. In another embodiment, no more than about 15% of the member surface is coated. In another embodiment, no more than about 10% of the member surface is coated. Further, it is preferred that the thickness of any such coating is less than about 0.1 inch, more preferably less than about 0.05 inch, and more preferably less than about 0.01 inch, and more preferably is about 0.005 inch.  
         [0039]    Resulting articles in accordance with the present invention exhibit excellent, consistent and reproducible performance over a broad range of temperatures from at least about −40° F. to 180° F.  
         [0040]    Turning now to another aspect of the present invention, as shown in FIG. 3, in one embodiment, the support member  100  has a first end portion  102  and a second end portion  104  and includes an intermediate central body portion  106  that is fabricated from a first material, which is preferably flexible, or is a rigid material that is fabricated to be flexible (e.g., with suitable corrugations or variable section thicknesses at desired hinge points). The first end portion or both are adapted for coupling the support member  100  to a seat.  
         [0041]    As will be appreciated, the central body portion  106  preferably includes a plurality of extending fingers, which may be the same or a different material as the balance of the material of the central body portion. Thus, as shown in FIG. 4, the central body portion  106  might have plastic fingers  108 , with metal elsewhere (e.g., as a metal spine  110 ), or vice versa. The plastic fingers might be insert molded onto the metal spine or attached in a subsequent operation, e.g., by placing over metal fingers (or protrusions for receiving the plastic fingers), by a coating process, or the like.  
         [0042]    In a preferred approach, the central body portion is a metal, such as a sheet spring metal, and the attachment portion is made of a molded plastic. In this manner, advantageously, the attachment portion may be provided as a self-lubricating material, or a material otherwise having a relatively low coefficient of friction. In turn, this permits for the elimination of the need for low friction sleeves or applying lubrication to contact surfaces, such as where the attachment portion is to move along guide wires in the seat back. Also, it is possible to fabricate intricately shaped attachment portion structures, e.g., including integrated sliding surfaces, and structures that permit for the performance of multiple functions within the seat. For instance, an attachment portion might have molded cable or wire guides for routing of cables, wires, conduits or the like within. It might include frames or supports for actuators, controls, electronics, or other components packaged within the seat. Likewise, fingers or other structure in the support member may be adapted for performing multiple functions, such as affording heating or cooling paths, or receiving suitable piezoelectric devices or other electromagnetic devices for providing a vibration source.  
         [0043]    It is contemplated that the support member might have sheet metal in face to face contact with some or all of at least one surface of the plastic attachment portions. Alternatively, the metal portion of the support member might adjoin the plastic attachment portions at the respective ends thereof. Combinations of the two might also be employed.  
         [0044]    In one embodiment, as shown in FIG. 5, a molded plastic, stamped metal or other suitable fabricated material is configured for defining a cantilever support member  112  including a central body portion  114 , support fingers  116  or other support structure. The support member, in turn, is adapted for attachment to a seat, either to a frame member in the seat back (not shown), or to a base  118  of a seat, e.g., to a member inserted in the base, to a seat pan, a seat cushion frame, to a seat track attachment, or otherwise. Optionally, for an embodiment as shown in FIG. 5, the support member is hinged for pivotal rotation along with an adjustable seat back. The interaction of moving parts in this embodiment benefits from lower coefficients of friction achieved according to the method and apparatus of the present invention.  
         [0045]    Using this type of approach, or any of the above approaches in which a molded plastic component is fabricated as part of the support member, it again is possible to increase the functionality of the back support device. For example, one embodiment contemplates the formation of a suitable molded fixture that is adapted to receive or house other vehicle components such as a thermoelectric device for heating or cooling the seat, electronics, sensors, air bag components, controls, actuators or the like.  
         [0046]    Turning to FIGS. 6 a - 6   c , the present invention also contemplates the variation of conventional packaging designs for back rest actuators. Thus, as an alternative to laterally spaced motors for driving or relieving arching of the central body portion, a single actuator  120  may be pivotally secured to a seat or a support arm such as a pivot bar  121  (e.g., shown in FIG. 6 a ). The actuator is equipped with an arm or push rod  122 , cable or the like, for driving one end of a support member  124  (shown in FIG. 6 a  in phantom) relative to the other, such as for arching or releasing an arch of the central body portion. In this manner, increased flexibility is possible from the use of a cantilevered support member. The interaction of moving parts in this embodiment benefits from lower coefficients of friction achieved according to the method and apparatus of the present invention.  
         [0047]    It should be appreciated also that this longitudinally aligned actuator packaging is not limited to cantilevered structures, but can be used for support members that are attachable at both of their respective ends to the vehicle seat assembly. For example, per FIG. 7, one type of longitudinally aligned actuator  130  might be disposed intermediate of the two end portions  126 ,  128  of a support member  132 . All actuators may be either manual or motor driven. The actuator preferably has at least two arms  134 ,  136  that are translatable relative to each other. For instance, in FIG. 7 c  the arms  134  and  136  are spaced about a rotatable sprocket  138  for extending or retracting them. Other like configurations are also possible. The interaction of moving parts in this embodiment benefits from lower coefficients of friction achieved according to the method and apparatus of the present invention.  
         [0048]    [0048]FIG. 8 illustrates another option for facilitating actuation of a support member. In this option, a seat back insert plate  140  or like structure is provided. The insert  140  has at least one guide track  142  (elevated or recessed) relative to a surface  144  of the insert. The track can be self lubricating, e.g., by selection of the material (e.g., PTFE, polyethylene, or the like) or a lubricant can be applied to it, such as an oil, graphite, the lubricants discussed previously, or the like. The interaction of moving parts in this embodiment benefits from lower coefficients of friction achieved according to the method and apparatus of the present invention.  
         [0049]    The concepts of the present invention also contemplate the relocation of various functions of the assemblies discussed previously to other places within the seat, in order to help simplify assembly operations, reduce parts or otherwise improve assembly manufacture. By way of example, turning to FIG. 9, the present invention contemplates that the support member need not include fingers or flex for bowing. A support member  146  (such as a manually or motor driven translatable bar, web, molded plastic structure, or the like) is adapted to be translated along a guide frame  148  or other suitable guide surface. For instance the support member  146  might be configured with ends  150 ,  152  for gripping (e.g., frictionally, clamping, snapping or the like) a nub formed on the frame, as seen from the sectional view of FIG. 9. Or a support member  146  might simply have an end (e.g., the above partially opened end of FIG. 9 b  or the enclosed end  150  of FIG. 9 c ) adapted to run along a guide wire or rod  154  as in FIG. 9 c . The guide surface on the guide frame might have differing profiles or thicknesses that vary along the length for directing the support member. To help secure the support member along the guide surface, the system may include notches or cut outs on the guide surface, the support member or both, for a ratchet and pawl locking adjustment. It may likewise have a screw down attachment, such as for clamping, employ locking pins, or the like. The interaction of moving parts in this embodiment benefits from lower coefficients of friction achieved according to the method and apparatus of the present invention.  
         [0050]    The function of the adjustable support fingers can also be re-located elsewhere within the seat, such to the upholstery, the padding, suitable webbing, or the like, either in, on or adjacent the front of the seat, the back of the seat, or both. In another embodiment (shown in FIG. 10), a plurality of individually tensionable webs, straps or wires  156  are disposed across a frame  158 . When tension is applied to one of the webs  156 , it becomes tight and applies increased local pressure toward the back of a user. The interaction of moving parts in this embodiment benefits from lower coefficients of friction achieved according to the method and apparatus of the present invention.  
         [0051]    The present invention also may be used in combination with other comfort and convenience features for a seat, such as side supports, thigh supports, recliners, pressure equalization bladders, or the like.  
         [0052]    In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.  
         [0053]    The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated.  
         [0054]    As various modifications could be made in the constructions and method herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, the apparatus and method of the present invention may be used on plastic flexible support members, or between the flexible support members and traction means. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.