Abstract:
A chair or other seating unit comprises a seat, a backrest, and an adjustable lumbar support, the adjustable lumbar support comprising a lumbar pad and a position adjustment means. The position adjustment means comprises a vertical adjustment means for mounting the lumbar support pad to the back rest, a substantially stationary support means that receives the vertical adjustment means, and a tension adjustment means, that releases the tension between the vertical adjustment means and the substantially stationary support means to allow the lumbar support to be positioned, and that increases the tension to hold the lumbar support means in a preferred selected position. The stationary support means is fixedly secured to the backrest.

Description:
[0001]     This is a continuation-in-part of patent application Ser. No. 29/194,354, filed Nov. 21, 2003. 
     
    
       [0002]     This invention relates to a chair having an adjustable lumbar support. More particularly, this invention relates to a chair having an adjustable lumbar support, wherein the adjustable lumbar support is movable on a substantially stationary support member.  
         [0003]     Chairs and other seating units having adjustable lumbar supports are well-known in the art. Such chairs typically comprise a frame, a seat mounted to said frame, a backrest mounted to said frame, and a plate fastened to the frame for supporting a lumbar support relative to the backrest. Such an arrangement is shown and described, for example, in U.S. Pat. No. 2,991,124, U.S. Pat. No. 3,106,423, and more recently in publication U.S. 2002/0043841 A1. These prior art chairs, while serviceable, suffer from complexity of design and multiplicity of parts. These factors make these chairs more expensive to manufacture, and more laborious to assemble. In addition, the number of mechanical parts and their manner of assembly can diminish the aesthetic appeal of such chairs.  
         [0004]     It is thus one object of the invention to provide a seating unit having an adjustable lumbar support, having a simple design that is easy to manufacture and assemble.  
         [0005]     It is another object of the invention to provide a seating unit having an adjustable lumbar support having a simple design that is aesthetically pleasing.  
         [0006]     It is still another object of the invention to provide an embodiment of a seating unit having an adjustable lumbar support wherein the adjustable lumbar support is adjustably mounted on a stationary support member.  
       SUMMARY OF THE INVENTION  
       [0007]     A chair or other seating unit comprises a seat, a back rest, and an adjustable lumbar support, the adjustable lumbar support comprising a lumbar support pad and a means for adjusting the position of the lumbar support pad. The position adjustment means comprises a stationary support means mounted to the backrest, a vertical adjustment means on which the lumbar support pad is mounted, and a tension adjustment means that is supported by the stationary support means. The tension adjustment means releases the tension between the vertical adjustment means and the stationary support pad means to allow the lumbar support pad to be vertically adjusted, and then increases the tension to hold the lumbar support pad in a preferred selected position. The design is simple, and does not require a separate frame mounted to a backrest. Because no separate frame is required, the design of the backrest can be more aesthetically pleasing.  
         [0008]     Other objects, advantages, and novel features of the present invention will be apparent from reading the detailed description of a preferred embodiment set forth below, taken together with the accompanying figures. 
     
    
     DESCRIPTION OF THE FIGURES  
       [0009]      FIG. 1  is a perspective view of a back rest embodying the adjustable lumbar support of the present invention;  
         [0010]      FIG. 2  is a side view of the embodiment of  FIG. 1 ;  
         [0011]      FIG. 3  is a rear view of the embodiment of  FIG. 1 ;  
         [0012]      FIG. 4  is an exploded view of the embodiment of  FIG. 1 , showing the means for adjusting the position of the lumbar support;  
         [0013]      FIG. 5  is an exploded cross-sectional view of an embodiment of the means for adjusting the position of the lumbar support of the present invention;  
         [0014]      FIG. 6  is an assembled view of the embodiment of  FIG. 5 ; and  
         [0015]      FIG. 7  is a view of an embodiment of a chair comprising an adjustable lumbar support of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     As illustrated in the Figures, a chair back  10  has a front surface  12  and a rear surface  14 . The chair back  10  is preferably of unitary construction, and includes a receiving means  16  integral therewith. In the illustrated embodiment, receiving means  16  is a slot having a narrower upper end  18  and a wider lower end  20 , and extends from about the center of backrest  10  down to the bottom of backrest  10 . It will be appreciated, however that receiving means  16  can be of any size and shape suitable for receiving a suitable portion of the vertical adjustment means, as shown below. As seen in  FIG. 2 , backrest  10  can be non-planar and preferably is convex with respect to a user&#39;s back, for greater comfort and support for a user.  
         [0017]     Lumbar support  25  comprises a pad  27  which has substantially greater width than height, the pad  27  being shaped and dimensioned to fit behind the lumbar region of a person&#39;s back and provide support therefor for a person sitting in the chair. Enclosed within the pad is a pad base  29  having a front surface  30  and a rear surface  31 . A longitudinal slot  32  extends through pad base  29 . The rear surface of slot  32  is provided with an inwardly directed collar  34 , the collar  34  having a plurality of scallop-shaped protrusions  36  formed in its radially inner edges, each scallop-shaped protrusion having a small recess or orifice  37  therethrough.  
         [0018]     Lumbar support  25  further comprises means  40  for adjusting the position of lumbar support pad  27 , the adjustment means  40  comprising vertical adjustment means  50 , stationary support means  60 , and tension adjustment means  70 . As used in this patent, the term “vertical” or “vertical adjustment” is not limited to a direction that is exactly 90 degrees to the horizontal, but is used to indicate that the general direction of motion is along the direction of the spine of a person seated in a chair of the present invention. Thus a pad that moves “vertically” as described herein may move, for example, along an arc that is either convex or concave.  
         [0019]     Vertical adjustment means  50  comprises extending member  52  sized and shaped to fit within slot  32  in pad base  29 . Extending member  52  has a plurality of axial ridges  54  along the outer surface thereof, said ridges  54  being complementary in size and shape to the protrusions  36  of inwardly directed collar  34  surrounding slot  32  of pad base  29 . Vertical adjustment means  50  further comprises a securement plate  56  disposed on the forward facing side of extending member  52 , said securement plate  56  being of the same width as longitudinal slot  32  but of shorter length. Securement plate  56  fits in sliding engagement in longitudinal slot  32 , the rear surface of securement plate  56  seating against the forward surface of inwardly directed collar  34 , the forward surface of securement plate  56  preferably being substantially flush with forward surface  30  of pad base  29 . Disposed within extending member  52  is a solid member  58  with a threaded hole  59  therein, the purpose of which will be discussed hereinbelow.  
         [0020]     Stationary support means  60  comprises base plate  62  having a front surface that abuts rear surface  14  of chair back  10  and a rear surface that abuts the front surface of adjustment knob  72  of tension controlling means  70 . Stationary support means  60  is fixedly secured to chair back  10  in the vicinity of receiving means  16 . In the illustrated embodiment, two screws  61  are used, one on either side of receiving means  16 , which screws  61  pass through screw holes  17  in backrest  10  and into threaded holes  63  that extend through base plate  62 . Other equivalent means of fixedly securing stationary support means  60  to chair back  10  will be readily apparent to those skilled in the art. Extending from the front surface of base plate  62  is a wall member  64  defining a cavity  65 . The inner surface  66  of cavity  65  has a form complementary to the axial ridges  54  on extending member  52 , which is received in cavity  65 . Wall member  64  has a forward edge  67 . When assembled together, pad base  29  is mounted to chair back  10  by vertical adjustment means  50 , such that extending member  52  fits through longitudinal slot  32  of pad base  29 , with inwardly directed collar  34  on the rear surface of longitudinal slot  32  being received in sliding engagement between the rear surface of securement plate  56  and the forward edge  67  of wall member  64 . When the user desires to adjust the vertical position of the lumbar support pad  27 , the user simply slides the pad up or down. The vertical movement of the pad will be limited by contact with the upper and lower ends of longitudinal slot  32  against extending member  52 . The axial ridges  54  on the exterior of extending member  52  fit within the protrusions  36  in collar  34  in friction fit relation, such that the protrusions  36  define fixed increments of vertical adjustment of lumbar pad  27 . The vertical adjustment means  50  and the collar  34  of longitudinal slot  32  are each made of a material with sufficient rigidity to maintain their shape and position relative to one another, but with enough flexibility to allow the ridges  54  to slide past protrusions  36  of collar  34 .  
         [0021]     Once the position of lumbar support pad  27  has been selected, it is desirable to firmly secure the pad in the selected position. Means  70  for adjusting the tension of the vertical adjustment means  50  comprises adjustment knob  72  having a threaded spindle  74  extending forwardly. Adjustment knob  72  is disposed rearwardly of base plate  62  of stationary support means  60 . Spindle  74  passes through an orifice in base plate  62  of stationary support means  60  and continues through receiving means  16  in chair back  10 , through cavity  65  of stationary support member  60 , and into the threaded hole  59  in the solid member  58  inside extending member  52  of mounting means  50 , such that the threaded end of spindle  74  engages threaded hole  59 .  
         [0022]     In operation, when the lumbar support pad  27  has been moved to a desired position, adjustment knob  72  is rotated until the threaded end of spindle  74  is received in threaded hole  59  in extending member  52 . At the same time, a plurality of bosses  67  on the forward surface of wall member  64  engages a plurality of small holes or recesses  37  in protrusions  36  of collar  34 . When the bosses  67  are engaged in the holes  37  then adjustable lumbar pad  27  is locked in place with respect to adjustment means  40 . When a user desires to re-position lumbar pad  27 , then the adjustment knob  72  is rotated in the opposite direction. This rotation releases the tension on stationary support means  60  and lumbar pad  27 , so that the bosses  67  can disengage from the holes  37  in collar  34 . Support pad  27  can then slide vertically, within the limits of longitudinal slot  32 , among the discrete locations defined by the protrusions  36 . When a preferred location is found, adjustment knob  72  is once again tightened, to secure the pad in place.  
         [0023]     The front surface  30  of pad base can be covered with padding  35  such as polyurethane foam. The pad  27  then can be upholstered, such as with fabric  37 , the upholstery extending over the padding and around the periphery of pad  27 , the upholstery being secured against rear surface  31 , as long as the longitudinal slot  32  is left uncovered on rear surface  31 .  
         [0024]     While a preferred embodiment of the invention has been described, the embodiment is disclosed by way of illustration and not by way of limitation. Those skilled in the art will recognize other embodiments and equivalents within the scope of the invention, which embodiments and equivalents are intended to be covered by the claims appended hereto.