Chair with adjustable lumbar support

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.

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.

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.

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.

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.

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

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.

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.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in the Figures, a chair back10has a front surface12and a rear surface14. The chair back10is preferably of unitary construction, and includes a receiving means16integral therewith. In the illustrated embodiment, receiving means16is a slot having a narrower upper end18and a wider lower end20, and extends from about the center of backrest10down to the bottom of backrest10. It will be appreciated, however that receiving means16can be of any size and shape suitable for receiving a suitable portion of the vertical adjustment means, as shown below. As seen inFIG. 2, backrest10can be non-planar and preferably is convex with respect to a user's back, for greater comfort and support for a user.

Lumbar support25comprises a pad27which has substantially greater width than height, the pad27being shaped and dimensioned to fit behind the lumbar region of a person's back and provide support therefor for a person sitting in the chair. Enclosed within the pad is a pad base29having a front surface30and a rear surface31. A longitudinal slot32extends through pad base29. The rear surface of slot32is provided with an inwardly directed collar34, the collar34having a plurality of scallop-shaped protrusions36formed in its radially inner edges, each scallop-shaped protrusion having a small recess or orifice37therethrough.

Lumbar support25further comprises means40for adjusting the position of lumbar support pad27, the adjustment means40comprising vertical adjustment means50, stationary support means60, and tension adjustment means70. 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.

Vertical adjustment means50comprises extending member52sized and shaped to fit within slot32in pad base29. Extending member52has a plurality of axial ridges54along the outer surface thereof, said ridges54being complementary in size and shape to the protrusions36of inwardly directed collar34surrounding slot32of pad base29. Vertical adjustment means50further comprises a securement plate56disposed on the forward facing side of extending member52, said securement plate56being of the same width as longitudinal slot32but of shorter length. Securement plate56fits in sliding engagement in longitudinal slot32, the rear surface of securement plate56seating against the forward surface of inwardly directed collar34, the forward surface of securement plate56preferably being substantially flush with forward surface30of pad base29. Disposed within extending member52is a solid member58with a threaded hole59therein, the purpose of which will be discussed hereinbelow.

Stationary support means60comprises base plate62having a front surface that abuts rear surface14of chair back10and a rear surface that abuts the front surface of adjustment knob72of tension controlling means70. Stationary support means60is fixedly secured to chair back10in the vicinity of receiving means16. In the illustrated embodiment, two screws61are used, one on either side of receiving means16, which screws61pass through screw holes17in backrest10and into threaded holes63that extend through base plate62. Other equivalent means of fixedly securing stationary support means60to chair back10will be readily apparent to those skilled in the art. Extending from the front surface of base plate62is a wall member64defining a cavity65. The inner surface66of cavity65has a form complementary to the axial ridges54on extending member52, which is received in cavity65. Wall member64has a forward edge67. When assembled together, pad base29is mounted to chair back10by vertical adjustment means50, such that extending member52fits through longitudinal slot32of pad base29, with inwardly directed collar34on the rear surface of longitudinal slot32being received in sliding engagement between the rear surface of securement plate56and the forward edge67of wall member64. When the user desires to adjust the vertical position of the lumbar support pad27, 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 slot32against extending member52. The axial ridges54on the exterior of extending member52fit within the protrusions36in collar34in friction fit relation, such that the protrusions36define fixed increments of vertical adjustment of lumbar pad27. The vertical adjustment means50and the collar34of longitudinal slot32are 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 ridges54to slide past protrusions36of collar34.

Once the position of lumbar support pad27has been selected, it is desirable to firmly secure the pad in the selected position. Means70for adjusting the tension of the vertical adjustment means50comprises adjustment knob72having a threaded spindle74extending forwardly. Adjustment knob72is disposed rearwardly of base plate62of stationary support means60. Spindle74passes through an orifice in base plate62of stationary support means60and continues through receiving means16in chair back10, through cavity65of stationary support member60, and into the threaded hole59in the solid member58inside extending member52of mounting means50, such that the threaded end of spindle74engages threaded hole59.

In operation, when the lumbar support pad27has been moved to a desired position, adjustment knob72is rotated until the threaded end of spindle74is received in threaded hole59in extending member52. At the same time, a plurality of bosses67on the forward surface of wall member64engages a plurality of small holes or recesses37in protrusions36of collar34. When the bosses67are engaged in the holes37then adjustable lumbar pad27is locked in place with respect to adjustment means40. When a user desires to re-position lumbar pad27, then the adjustment knob72is rotated in the opposite direction. This rotation releases the tension on stationary support means60and lumbar pad27, so that the bosses67can disengage from the holes37in collar34. Support pad27can then slide vertically, within the limits of longitudinal slot32, among the discrete locations defined by the protrusions36. When a preferred location is found, adjustment knob72is once again tightened, to secure the pad in place.

The front surface30of pad base can be covered with padding35such as polyurethane foam. The pad27then can be upholstered, such as with fabric37, the upholstery extending over the padding and around the periphery of pad27, the upholstery being secured against rear surface31, as long as the longitudinal slot32is left uncovered on rear surface31.

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.