WO2003099071A1

WO2003099071A1 - Seating structure having an adjustable body support member

Info

Publication number: WO2003099071A1
Application number: PCT/US2003/016034
Authority: WO
Inventors: Jerome Carmel Caruso; Steven Jerome Caruso
Original assignee: Herman Miller, Inc.
Priority date: 2002-05-20
Filing date: 2003-05-20
Publication date: 2003-12-04
Also published as: AU2003243286A1

Abstract

A seating structure includes a frame (4) and a body support member (6) having a flexible support member. The body support member has a first (20) and second (22) portion, with one of the first and second portions being connected to the frame at a first location (8), and the other of the first and second portions being slidably connected to the frame at a second location spaced from the first location. The second location is moveable toward and away from the first location. In a preferred embodiment, one of the first and second portions is pivotally connected to the frame about a horizontal axis at the first location. In various embodiments, the body support member is a back and/or a seat. In one embodiment, an armrest (12) can be further moveably supported on the frame. A method of adjusting a body support member on a seating structure includes moving the second location toward and away from the first location.

Description

SEATING STRUCTURE HAVING AN ADJUSTABLE BODY SUPPORT

MEMBER

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/381 ,769, filed May 20, 2003, the entire disclosure of which is hereby incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to chairs and seating normally associated with, but not limited to, residential, commercial office work and automotive seating, and in particular to a seating structure having an adjustable body support member.

BACKGROUND

Chairs and seating structures employ a number of methods and devices that enhance the user's comfort and promote ergonomically healthy sitting. Often these chairs include a postural development known as a lumbar curve, which serves to promote proper support of the spine. Other contours in other areas of a seat and back have been investigated, also to encourage the proper support and positioning of a users scapulas, pelvis and spine. Often these chairs include a pair of armrests, which may or may not be adjustable. Various approaches to making a chair's seat and back form fitting for various users are known in the industries of seating manufacture. These approaches range from the rather traditional use of contouring synthetic foam to providing seat/back shells with a degree of flex. There have also been approaches that use a frame with a membrane or sling stretched or supported on the frame. There have also been several approaches that allow the user to alter the positioning or contour of a seat cushion or back. These include a bladder that can be inserted between the seat shell and the user and that can be inflated or deflated; and various mechanisms, which act in a manner similar to a bladder, and which typically are also inserted between the seat shell and the user and can be mechanically actuated. Several problems exist with each of these approaches though, ranging from expense of manufacture to difficulty in design. For example, an adjustment mechanism must be hidden within an upholstered cushion or be configured so that it is aesthetically pleasing. It also can be difficult to design a chair with the proper contours for the full range of the population. The resulting designs and contours are necessarily compromises, and thus are not optimal for any given individual. In an effort to overcome these limitations, manufacturers have produced "sized" (i.e., small, medium and large) chairs that effectively narrow the amount of contouring- compromise that the designer must normally exercise. However, the manufacturer must then maintain large inventories of the seating structures to satisfy all customers.

SUMMARY

In one aspect, one embodiment of a seating structure includes a frame and a body support member having a flexible support member. The body support member has a first and second portion, with one of the first and second portions being connected to the frame at a first location, and the other of the first and second portions being slidably connected to the frame at a second location spaced from the first location. The second location is moveable toward and away from the first location. In a preferred embodiment, one of the first and second portions is pivotally connected to the frame about a horizontal axis at the first location.

In one preferred embodiment, the body support member is a back. In this embodiment, the first and second portions are preferably formed as a top and bottom of the back respectively. In another preferred embodiment, the body support member is a seat.

In another aspect, a method of adjusting a body support member on a seating structure includes moving the second location toward and away from the first location. In one embodiment, the body support member is adjustable in a "dynamic" way in that the member is in a constant state of adjustment. In another embodiment the body support member may be adjusted by the user and then locked into the desired position by the user. In yet another embodiment, at least one of the structural components that facilitate adjustment of the body support surfaces also serves to support an armrest which may or may not be adjustable.

The present embodiments provide significant advantages over prior seating structures. For example, there are several aspects to sizing. The first is the overall sizing of the surfaces, e.g., width, height etc. As far as comfort is concerned, this is the least important aspect of seating surface design. Appropriately sized seating surfaces can be formulated that satisfy the extremes.

A more important aspect in achieving seating comfort is the contouring of the body support surface, such as the backrest. The contour of a user's back can vary between a small individual to a large one. Additionally, some individuals who seemingly share the same body types prefer differing contours including for example and without limitation stronger/weaker lumbar contours.

The presently preferred embodiments described herein address this need for variable contouring by the innovative ability of the back and/or seat member to flex into the appropriate shape for the occupant. In one embodiment the backrest is preferably molded in a predefined contour and the user is thereafter allowed to alter that contour in an easy and efficient manner. Additionally, the seating structure can be manufactured so as to yield greater economy, ease and superior aesthetics. Further advantages in comfort can be realized if the initial contours of the seating structure are in the proper range for the occupant. Through the unique method of construction of the seating structure, these various advantages are achieved.

The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the following claims. The presently preferred embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is rear elevation view of one embodiment of a chair; Fig. 2 is side elevation view of the chair shown in Figure 1;

Fig. 3 is rear elevation view of the chair with various components positioned in different positions relative to those in Figure 1 ;

Fig. 4 is side elevation view of the chair shown in Figure 3 but with the right arm in a lowered position;

Fig. 5 is a cross sectional view taken along line 5-5 in Figure 1;

Fig 6 is an enlarged side view of the backrest shown in Figure 1; Fig 7 is an enlarged side view of the backrest shown in Figure 3; Fig 8 is a rear perspective view of another embodiment of the chair; Fig 9 is partial, perspective view of a portion of a back secured to a frame;

Fig. 10 is a partial, perspective view of a pivot bracket secured to a frame;

Fig. 11 is an exploded, perspective view of a pivot bracket, latch device and frame;

Fig. 12 is another exploded, perspective view of a pivot bracket, latch device and frame;

Fig. 13 is a partial, perspective view of a portion of an armrest secured to a frame;

Fig. 14 is a partial exploded, perspective view of an armrest and a frame;

Fig. 15 is another partial exploded, perspective view of an armrest and a frame;

Fig. 16 is a cross-sectional view of a frame upright;

Fig. 17 is a side view of a seating structure with a representative person in the third percentile of the population sitting therein;

Fig. 18 is a side view of a seating structure with a representative person in the ninety-fifth percentile of the population sitting therein;

Fig. 19 is a side view of one embodiment of the seating structure;

Fig. 20 is a rear view of the seating structure shown in Fig. 19 with a schematic representation of the lumbar support member and back member contours; Fig. 21 is a rear view of the back member with a schematic representation of the contours; Fig. 22 is side view of the back member shown in Fig. 21;

Fig. 23 is a cross-sectional cut of the back member taken along line 23-23 of Fig. 21, with the back member in a noπrial, unflexed condition;

Fig. 24 is a cross-sectional cut of the back member taken along line 24-24 of Fig. 21;

Fig. 25 is a cross-sectional cut of the back member taken along line 25-25 of Fig. 21;

Fig. 26 is a cross-sectional cut of the back member taken along line 26-26 of Fig. 21; Fig. 27 is a center cross-sectional view of the back member in a bowed and flattened position; and

Fig. 28 is an exploded perspective view of an ararrest assembly.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS Referring to Figs. 1-4 and 6-8, one embodiment of a body support member is shown as a backrest having a flexible back member 6 and a support frame 4. Any of the common production molding methods known could be used to produce the back member 6 and many other of the parts of the seating structure including, but not limited to, injection, blow, or roto molding. Additionally, this structure could be realized through other manufacturing techniques such as lamination, stamping, punching, or any other known manufacturing techniques for making such members. In the embodiment of Figs. 1-4, 6 and 7, the support frame 4, is depicted as two rods, or tubular or rod structures, forming a pair of uprights 24 (each formed from two rods) that extend predominantly vertical with respect to the back member 6. In this embodiment, the frame elements provide unique aesthetics and visuals.

In an alternative embodiment, shown in Figs. 8-16, the uprights are each formed as single member, with a cross member 123 joining an upper end of each upright. In one embodiment, the uprights 124 have a generally T-shape cross- section, with a front section 126 and a rear section 128 that provides strength and resistance to bending. The uprights can be made of steel, aluminum or other materials.

In various embodiments, the uprights can be formed within another structure, with the second structure serving as a cover or as an additional support structure to the first. Additionally, the support members do not have to be round or T-shaped; many profile shapes are considered to be alternatives. A shaped profile may be desirable in situations where only a single member is contemplated. This is because rotationally locking (about a vertical axis) the corresponding slide members (slide blocks and arms) is facilitated on a non round profile. The back is attached to the support frame in at least two locations. In one embodiment, a first portion, shown as a top 20 of the back, is pivotally secured to the frame, and in particular to the uprights 24, 124, at a first location defined by pivot joints 8, which define a horizontal axis. A second portion, shown as a bottom 22 of the back, is slidably secured to the frame 4 with a slide element 2 at a second location. It should be noted that the locations of the pivot joint and slide element are interchangeable, in other words, the slide can positioned at the top of the back and the pivot at the bottom.

The top pivot joint 8 can be formed with a pivot pin, as shown in the Figures. Alternatively, the pivot joint 8 can assume other forms, which are not hard pivot points, but serve a similar function. For example and without limitation, the pivot joint could be formed by a rubber mount or a plastic hinge, which can flex and yield in a virtual pivoting motion.

Referring to Figs. 1-8, the flexible back member 6 has an inherent shape/contour molded into it. In particular, the back member has a forwardly protruding contour adjacent the lower portion of the back, for example at the lumbar and/or sacral region of the back. As the user leans back against back member 6, it pivots about a horizontal axis joint 8. At the same time, the bottom 22 of the back, and in particular a slide element 2, slides or translates along the upright 24 away from the pivot joint 8 so as to change the shape of the back, e.g, to flatten it. For example, the back and back member 6 can be moved from the position shown in Figs. 1 and 23 to a new position shown in Figs. 3, 4 and 27, where the slide element 2 is moved from a first position (2') to a second lower position (2), and the back member 6 has a generally flatter profile. Of course, the bottom of the back member can be moved toward the top thereof to form a greater bowed section in the back member. In various embodiments, portions of the back member, for example the most forwardly extending portion of the back member (e.g., the pelvic and lumbar region) can be moved up to 4.00 inches between a maximum bowed and maximum flattened position. In other embodiments, the back member is moved between about 0.50 inches and about 3.00 inches between a maximum bowed and maximum flattened position. In other embodiments, the back member is moved to a maximum of between about 1.00 inches and about 2.00 inches between a maximum bowed and maximum flattened position, and more preferably about 1.75 inches. These various changes in the depth of the bowed section are achieved with a minimal height change. In other words, the vertical position of the pelvic and lumbar regions are not shifted a large amount. Of course, it should be understood that the amount of flattening is dependent on a number of parameters, including the initial curvature of the back member, the distance between the pivot joint 8 and the slide element 2, and the range of motion of the slide element relative to the pivot joint. In one exemplary embodiment, and in order to achieve these various flattening dimensions, the bottom 22 of the back member is moveable up to 2.50 inches relative to the top thereof. In other embodiments, the bottom is moveable a maximum of about 2.00 inches, about 1.50 inches, about 1.25 inches, or as little as about 0.25 inches. In one exemplary embodiment, an approximate 2.00 inch fore- aft movement of the lumbar region of the back member is achieved by an approximate 0.875 inch vertical movement of the lower portion of the back.

Preferably, the resilient, elastic properties inherent to the back member 6 will cause the back to return to its original shape when outside user forces are removed. In other embodiments, a spring may be provided to return the back to its normal, at-rest position. In various embodiments, one or more portions of the back member can be made of a polymeric material, for example an injection molded nylon or polypropylene material, which can be translucent, clear, opaque and/or solid, e.g., colored. In one embodiment, the back member is formed as a flexible shell or mat having a plurality of boss structures joined by interconnecting webs, which can include various hinge structures that allow the back member to extend as the bottom thereof moves relative to the top. The mat can also have a plurality of apertures or openings formed therethrough. The seat and back can be made as disclosed for example and without limitation in U.S. Application No. 09/897,153, filed June 29, 2001 and entitled "Cellular Chair Construction" and U.S.

Application No. 10/365, 682, filed February 12, 2003 and entitled "Tilt Chair Having A Flexible Back, Adjustable Armrests and Adjustable Seat Depth, and Methods for the Use Thereof," the entire disclosures of which are hereby incorporated herein by reference. The back member, and in particular the shell or mat, can be left exposed, or it can be covered with upholstery or padding.

In other embodiments, the back can be formed from a frame having an elastic membrane secured thereto, as disclosed for example and without limitation, in U.S. Patent No. 6,059,368, the entire disclosure of which is hereby incorporated herein by references. The frame can provide a resilient structure that flexes as it moves or is flattened or bowed in response to a portion thereof being moved along the frame uprights.

In other embodiments, the back member can be provided with horizontally oriented slots or openings, vertically spaced and arrange for example along the lumbar region. In yet another embodiment, shown in Figs. 17-19, a region of the back member 6 is provided with horizontally oriented bellows or pleats, otherwise referred to as virtual or living hinges, which allow the back member to expand or contract as the lower portion thereof slides along the frame. The hinge structures form an expandable section 200 of the back member. In one preferred embodiment, the expandable section 200 of the back member is formed in the lumbar region of the back member, although it should be understood that the entire back member can be formed with such a construction, or that other portions thereof can be so constructed.

The back member 6 can also be provided with various contours that optimize the support and stabilization of the pelvic region of the user, as well as be provided with an adjustable back support member, for example an adjustable lumbar back support member. The pelvic region of the population is very predictable for most body types and sizes. In particular, the height of the pelvis varies approximately plus or minus 0.625 inches from the 3^rd to the 97^th percentile of the population. In this way, the transition between the pelvis 202 and the first three vertebrae 204 is also predictable, as shown in Figs. 17 and 18. The pelvic and lumbar regions of the human body transition concurrently with an inward and outward movement of the lower back. Likewise, the pelvic region of the back member 206 is transitioned into the areas congruent or adjacent thereto, for example into the lumbar region 208. In one embodiment, shown in Figs. 20-27, the back member is provided with various contours to optimize the support of the user's back. For example, as shown in Figs. 20-24, a center portion 210 of the lower back member is forwardly protruding when taken along a horizontal cross-section so as to provide a pelvic stabilization contour. Side portions 212 of the lower region of the back member are rearwardly protruding along that same cross-section. The forwardly protruding center portion 210 is transitioned or feathered/blended out, with the rearwardly protruding side portions growing in width and the forwardly protruding center portion lessening in width, as the center portion moves upwardly along the back (illustrated with contour lines 214). Eventually, the entirety of the back member 206 taken along a horizontal cross-section is provided with a generally rearwardy protruding contour as shown in Figs. 21, 22, 25 and 26.

Referring to Figs. 20, 21 and 25, the back member is also provided with a spinal relief contour 216 that extends vertically along the center portion of the back member. The spinal relief 216 has a greater rearward curvature than the surrounding portions of the back member, so as to provide a recess 218 that relieves pressure on the spine of the user. Referring to Figs. 19 and 20, an adjustable back support member 230 is vertically, adjustable secured to the back member 6. In particular, the back support member 230 has opposite end portions 232 that are slidably secured to the edge 234 of the back member, which can be formed for example with a bead. The adjustable back support member 230 can be used to vertically adjust the transition from the pelvic support region 206 of the back member to the lumbar region 208 thereof.

It should be understood that the back can remain dynamic, meaning that the bottom 22 continuously slides up and down on the uprights 24 in response to the weight and position of the user. In another preferred embodiment, a latch device

30 is provided such that once a desired position is reached, the back can be locked to the frame and maintained in a particular configuration until another adjustment is desired. Of course, the user could raise the back, and thus achieve a curve greater that the one that was originally formed into the back member 6, and then lock it into the new position. The latch device can be positioned at any point between the back member 6 and the frame 4. The latch device 30 can be configured by many known methods of locking such as teeth and a pawl, a releasable friction fit, etc. For example, in one embodiment, the latch device is formed as a frictional cam lock. In one preferred embodiment, for ease of use, manufacturability, aesthetics, etc., the latch device is incorporated into the slide element 2.

In operation, the user releases the latch device, which may be on one side of the chair, both sides (left and right) of the chair, or in the center of the chair in the case of a centrally supported chair back, and then adjust the back member to a desired position and contour. The latch device is thereafter engaged, thus locking or fixing the back member in its new shape. In another mode, the latch device is disabled, or omitted altogether, such that the backrest is maintained in the dynamic floating state. In another embodiment, the latch device can be either disabled with the back in a dynamic state it can be engaged so as to maintain the back member in a static locked condition. As shown in Figs. 9-12, one embodiment of the upright 124 includes a vertically extending rack 132 having a plurality of vertically spaced teeth or slots 134. A latch device 30, configured as a pawl, is connected to the back and selectively engages the rack 132 to lock the back member 6 to the frame 4. Of course, it should be understood that the rack can be formed on the back, with the latch device, or pawl, connected to the frame.

In one embodiment, the slide element 2 is formed as a two-piece housing 136 having a pair of legs 138 that are spaced apart and shaped to engage and slide along the front portion 126 of the upright. The housing and other slide element components can be made of injection molded nylon or other plastics, or can be made of metal, such as aluminum. As shown in Fig. 12, the housing has a vertical guide 140 formed by a pair of flanges and a pair of horizontally oriented sockets 142. In addition, a horizontally oriented pivot axle 144 is formed adjacent a front of the housing. An opening 146, shown as a slot, is formed in the front of the housing so as to provide access to the pivot axle 144. In addition, the front surface

148 of the housing is curved. A bottom 150 of the housing has an opening 152 formed therein.

Referring to FIGS. 10-12, an actuator 154, shown as a button, is disposed in the housing and is exposed to the user through the bottom opening 152. A pair of retainer flanges 156 are disposed within the housing and prevent the actuator from being removed through the opening 152. The actuator 154 includes a button 170 and a stem 158 that is slidably received in the guide 140, which guides the actuator in a generally vertical direction. A pawl 160 is pivotally mounted in the sockets 142 and has an integrally molded spring 168 that engages a top of the housing. The pawl 160 includes a first engagement arm 162 and a second actuator arm 164 extending respectively from a pivot axis 166. It should be understood that a separate spring, for example a compression or tension spring, can be disposed in the housing to act on the pawl member.

In operation, as the user pushes the actuator button 170, the stem 158 is biased against the actuator arm 164 of the pawl in opposition to the spring 168, which engages a top of the housing 136. As the actuator arm 164 is pivoted by the stem about axis 166, the engagement arm 162 also is pivoted about the axis out of engagement with the rack 132. The back can thereafter be moved up and down on the upright 124 to a desired position, as described above. After the desired position is selected, the button 170 is released such that the spring 168 pivots the engagement arm 162 of the pawl into engagement with the rack 132 thereby fixing the location of the bottom 22 of the back.

In yet another embodiment of the invention, the slide 2 is configured as a pivot bracket, which is pivotally connected to the bottom of the back member to facilitate ease of movement of the back member 6 as it slides on the uprights 124. In one embodiment, shown in Fig. 9, the back member 6 is configured with one or more flanges 172 that extend through the opening in the pivot bracket and are pivotally connected to the pivot axle 144. The curvature of the front surface 148 of the pivot bracket housing further allows the back member 6 to pivot about the pivot axis 144 without interference from the pivot bracket. The pivotal connection between the bottom of the back and the frame can be alternatively be formed as a virtual pivot, e.g., as a flexure joint as has already been described for the upper connection between the back member 6 and the frame 4. In addition, an appropriate clearance and fit between the slide element 2 and the frame 4 can provide some degree of pivoting. Of course, it should be understood that the bottom of the back is not necessarily pivotally connected to the frame, and can constitute only a sliding/translation joint, with the flexibility of the back member allowing the bottom thereof to slide and translate along the uprights.

In yet another embodiment, at least one of the structural components that facilitates adjustment of the seating surfaces also serves to support an armrest which itself may or may not be adjustable. This can be seen by referring to

Figs. 1, 3, 8 and 13-15. In particular, each armrest 12 includes a base 50 having a cavity 52 formed therethrough. The cavity is preferably formed with a draft, for example about 3 degrees, with the components fitting therein being similarly drafted. The cross-sectional shape of the cavity is generally the same as, but slightly larger than, the cross-sectional shape of the upright 124. The armrest further includes front and back bracket members 54, 56 that are shaped to be received in the cavity 52. Each bracket member 54, 56 has an inner surface that is shaped to mate with and slide along the uprights 124. The base 50 and front bracket 54 have aligned, laterally elongated openings 58, 60. An actuator 62 is disposed between the inner surface of the base 50 and the outer surface of the front bracket 54, with a pawl portion 64, formed as a pair of teeth, extending through the opening 60 formed in the front bracket. The actuator 62 further includes an integrally molded spring 66, which is biased against the forwardly facing surface of the front bracket. A button 68 extends through a portion of the opening 58 of the base 50 and is exposed for engagement by the user. The actuator further includes a vertically oriented pivot axle 70 that is snap-fitted into engagement with a pair of tabs 72 formed on the front bracket.

Referring to Fig. 28, a screw 250 or other fastener is threaded through a flange foπned in one or both of the front and rear brackets 54, 56 and engages an elastomeric member 252 disposed between the front and rear brackets so as to bias them against the base. The screw 250 is torqued to a predetermined amount. The base can be provided with an upper flange 260, which engages the tops of the brackets and locates them relative to the base 50. In the embodiment shown in Fig. 28, the front and rear brackets are configured with key members 256, or tabs, and key holes 258 which locate the brackets relative to each other. In operation, the user pushes on the button portion 68 of the actuator in opposition to the biasing force of the spring 66 so as to disengage the pawl 64 from the rack 132 formed on the upright. The user thereafter moves the ami 12 to the desired position, whereinafter the actuator 62 is released, with the spring 66 biasing the pawl 64 into engagement with the rack 132 and thereby locking the armrest in a desired position.

The latch device for securing the arm to the frame can be configured by many known methods of locking such as the teeth and pawl disclosed herein, or with a releasable friction fit, etc. For example, in one embodiment, the latch device is formed as a frictional cam lock. In yet another embodiment, the body support member is configured as a seat 80, which includes a flexible seat support member. The support member can flex and move in much the same manner as has already been described for the back member 6. In one preferred embodiment, the seat is maintained in the dynamic mode, and functions as a shock absorber as the user sits thereon by automatically adjusting to the user. Referring to Fig. 2, it can be seen that the seat has a first portion 82, shown as a rear of the seat, pivotally connected to a base structure or frame at pivot axis 14, which is common to the seat and the base structure. A second portion 84, shown as the front of the seat and configured with a slide 18, is pivotally connected to the base structure or frame at the pivot axis 16. The pivot and sliding configuration may already be provided for the purpose of a chair tilting mechanism. The pivot joint 14 operates much in the same manner as the pivot joint 8 does on the back. Likewise, the pivot-slide 16, 18 operates in much in the same manner as slide 2 does for the back. In this way, the seat can elongate or change its contour in much the same manner as the back.

The slide-pivot relationships are interchangeable meaning, in other words, the slide 18 could be positioned on the base member just as easily as on the seat member, and such arrangements could also be positioned at the rearward location of pivot 14, and the pivot 14 could be positioned at the forward location of the pivot, slide 16, 18. As previously described for the back, a latch device may be provided for preventing movement of the seat once a given position has been achieved.

Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. As such, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims, including all equivalents thereof, which are intended to define the scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A seating structure comprising: a frame; and a body support member comprising a flexible support member, said body support member having a first and second portion, wherein one of said first and second portions is connected to said frame at a first location, and the other of said first and second portions is slidably connected to said frame at a second location spaced from said first location, and wherein said second location is moveable toward and away from said first location.

2. The seating structure of claim 1 wherein said one of said first and second portions is pivotally connected to said frame about a horizontal axis at said first location.

3. The seating structure of claim 2 wherein said other of said first and second portions of said flexible support member is further pivotally supported relative to said frame at said second location.

4. The seating structure of claim 2 wherein said body support member comprises a back and wherein said first and second portions comprise a top and bottom of said back.

5. The seating structure of claim 4 wherein said back further comprises a pivot bracket, wherein said flexible back member is pivotally connected to said pivot bracket and wherein said pivot bracket is slidably connected to said frame at said second location.

6. The seating structure of claim 4 wherein said top of said back is pivotally connected to said frame at said first location and said bottom of said back is slidably connected to said frame at said second location.

7. The seating structure of claim 4 wherein said frame comprises a pair of laterally spaced uprights, wherein said one of said top and bottom is pivotally connected to each of said pair of uprights about said horizontal axis at a pair of first locations, and wherein said other of said top and bottom is slidably connected to each of said pair of uprights at a pair of second locations vertically spaced from said pair of first locations.

8. The seating structure of claim 7 further comprising a pair of armrests slidably supported on said pair of uprights respectively.

9. The seating structure of claim 8 further comprising a pair of latch devices each of which is releasably engaged between one of said pair of armrests and one of said uprights, said latch devices releasably securing said armrests to said frame.

10. The seating structure of claim 9 wherein one of said pair of uprights and said pair of armrests comprises a pair of vertically extending racks, and wherein said latch devices each comprise a pawl disposed on the other of said pair of uprights and said pair of armrests, wherein said pawls are independently selectively engaged with said racks so as to releasably secure said pair of armrests to said pair of uprights.

11. The seating structure of claim 4 wherein said flexible support member comprises an expandable section, wherein said back can expand between said top and bottom thereof.

12. The seating structure of claim 2 further comprising a latch device releasably engaged between said other of said first and second portions and said frame, said latch device releasably fixing said second location relative to said first location.

13. The seating structure of claim 12 wherein one of said frame and said body support member comprises a rack, and wherein said latch device comprises a pawl disposed on the other of said frame and said body support member, wherein said pawl is selectively engaged with said rack so as to releasably fix said second location relative to said first location.

14. The seating structure of claim 2 wherein said body support member comprises a seat.

15. A method of adjusting a body support member on a seating structure comprising: providing a frame and said body support member comprising a flexible support member, wherein said body support member has a first and second portion, wherein one of said first and second portions is connected to said frame at a first location, and the other of said first and second portions is slidably connected to said frame at a second location spaced from said first location; and moving said second location toward and away from said first location.

16. The method of claim 15 wherein said moving said second location toward and away from said first location further comprises pivoting said one of said first and second portions of said body support member about a horizontal axis at said first location.

17. The method of claim 16 wherein said moving said second location toward and away from said first location further comprises pivoting said other of said first and second portions of said body support member about a second horizontal axis spaced from said first horizontal axis.

18. The method of claim 16 wherein said body support member comprises a back, and wherein said first and second portions comprise a top and bottom of said back respectively.

19. The method of claim 18 wherein said back further comprises a pivot bracket, wherein said flexible back member is pivotally connected to said pivot bracket and wherein said moving said second location toward and away from said first location further comprises sliding said pivot bracket along said frame and pivoting said other of said top and bottom of said back about a second horizontal axis spaced from said first horizontal axis, wherein said pivoting said other of said top and bottom of said back comprises pivoting said flexible back relative to said pivot bracket at said second horizontal axis.

20. The method of claim 18 wherein said top of said back is pivotally connected to said frame at said first location and said bottom of said back is slidably connected to said frame at said second location.

21. The method of claim 18 wherein said frame comprises a pair of laterally spaced uprights, wherein said one of said top and bottom is pivotally connected to each of said pair of uprights about said horizontal axis at a pair of first locations, and wherein said other of said top and bottom is slidably connected to each of said pair of uprights at a pair of second locations vertically spaced from said pair of first locations, and wherein said moving said second location toward and away from said first location comprises moving said pair of second locations toward and away from said pair of first locations.

22. The method of claim 21 further comprising providing a pair of armrests slidably supported on said pair of uprights respectively, and further comprising sliding at least one of said armrests along one of said pair of uprights.

23. The method of claim 22 further comprising providing a pair of latch devices each of which is releasably engaged between one of said pair of armrests and one of said uprights, wherein said sliding at least one of said amirests along one of said pair of uprights comprises releasing a respective one of said latch devices and further comprising engaging said one of said latch devices and thereby securing said at least one of said armrests to said one of said pair of uprights.

24. The method of claim 23 wherein one of said pair of uprights and said pair of armrests comprises a pair of vertically extending racks, and wherein said latch devices each comprise a pawl disposed on the other of said pair of uprights and said pair of armrests, wherein said pawls are independently selectively engaged with said racks so as to releasably secure said pair of armrests to said pair of uprights, and wherein said releasing said respective one of said latch devices comprises disengaging a respective one of said pawls from one of said racks, and wherein said engaging said one of said latch devices and thereby securing said at least one of said armrests to said one of said pair of uprights comprises engaging said one of said racks with said one of said pawls.

25. The method of claim 16 further comprising providing a latch device releasably engaged between said other of said first and second portions and said frame, and releasably fixing said second location relative to said first location with said latch device.

26. The method of claim 25 wherein one of said frame and said body support member comprises a rack, and wherein said latch device comprises a pawl disposed on the other of said frame and said body support member, wherein said releasably fixing said second location relative to said first location with said latch device comprises selectively engaging said pawl with said rack.

27. The method of claim 16 wherein said flexible support member comprises an expandable section, and wherein said moving said second location toward and away from said first location comprises retracting and expanding said expandable section respectively.

28. The method of claim 16 wherein said body support member comprises a seat.