Abstract:
Lightweight chair from a single unitary die-cut and scored generally rectangular blank of sheet material which is collapsible for easy storing and carrying, and which pops open for easy set-up. The lower 10-20% of the blank has a plurality of flaps gulable to the inner face of adjoining sidewall panels to form a reinforced base perimeter. Half of the blank forms the chair base sidewalls, and the remaining upper half forms a pair of adjoining seat/back panels which are delineated from the sidewalls by a set of generally W-shaped score lines. An assembly tab at one end is fastened to the opposite side of the other end of the blank to form in cross-section an enclosed polygon, preferably a modified hexagon of unequal sides. A first of the pair of seat/back panel assemblies is folded down with one or more tabs or flaps frictionally engaging one or more of the sidewall panels. Then the second of the pair of seat/back panel assemblies is folded over the first, and an interlocking tab engages a slot in the first to complete the assembly. In use the seat is oriented with one of the polygon (hexagon) corners forward to provide leg room on either side. A generally triangular or trapezoidal backrest panel is joined to a generally rectangular middle seat panel, and the seat portion in joined in turn to a generally triangular legrest panel.

Description:
FIELD OF THE INVENTION 
     This invention relates to an article of furniture, and more particularly to a lightweight chair made from sheet material which is collapsible for easy storing and carrying, yet which is simple to manufacture and set up and sufficiently inexpensive to be disposable, preferably in a manner in which its materials can be recycled, and which is assembled from a single die-cut and scored blank. 
     BACKGROUND OF THE INVENTION 
     There have been many attempts in the prior art to fabricate lightweight chairs and other furniture items from corrugated cardboard. While such cardboard materials have a relatively brief useful lifespan because they are not inherently highly durable, the low cost of the materials and methods of manufacture have resulted in relatively inexpensive chairs, thus justifying the relatively short useful lifespan. 
     Exemplary of the art in this field are the following patents: Steuer U.S. Pat. No. 3,149,880; Snyder U.S. Pat. No. 3,178,227; Downes U.S. Pat. No. 3,220,362; Giebel U.S. Pat. No. 3,463,546; Caigan U.S. Pat. No. 3,604,751; and Klein U.S. Pat. No. 4,085,970. To our knowledge, none of these has met with general acceptance or marketing success which we believe may be due to the relative complexity of these chairs in terms of the blank layout and material wastage, the difficulty of &#34;set-up&#34; or assembly of the chairs by the consumer at the time of use, the difficulty in disassembly for storage (they are not easy to knock down for storage), and relatively poor seating comfort. While complex or multi-part blanks are difficult to set up and knock down for storage or shipping, they also very significantly increase the cost, thus making them unattractive to the consumer in view of their very short lifespan. 
     To our knowledge, there is no single-use, lightweight, portable chair which is fabricated from a single, standard-size sheet of relatively rigid material to form a chair that is inexpensive, simple to manufacture, can be easily set up and knocked down, is easy to carry, and is ergonomically comfortable. 
     Accordingly, there is a need in the art to provide such type of chair which is economic even from a single-use point of view for outdoor festivals, special events, or any other situation in which large crowds gather for a relatively short period of time where there is no immediate seating readily available. Such use extends to campgrounds, parks, garden parties, barbecues, picnics, beach usage, and the like, where it is desirable to provide inexpensive seating for limited use and which may be conveniently disposed-of when desired, or knocked down to flat form for transport and storage. Another important use is for children&#39;s furniture as children, during growth years, need various sizes of furniture before being able to be comfortable in adult-sized furniture. In addition, this type of furniture would be useful in children&#39;s playrooms or parties as it will save wear and soiling of other household furniture. 
     THE INVENTION 
     Objects 
     It is among the objects of this invention to provide a chair fabricated from a single, standard-sized sheet of a lightweight, high-strength, relatively rigid material in sheet form such as cardboard, fiberboard or plastic. 
     It is another object of this invention to provide an improved disposable chair which is formed from a one-piece die-cut and prescored blank in which all the chair elements are integrally connected. 
     It is another object of this invention to provide a preassembled chair unit which can be folded flat either for shipping or storage, and which pops open for easy set-up of the chair for use. 
     It is another object of this invention to provide a preassembled chair unit which can be set up in a few, very simple and quickly performed manual steps without the use of any tools. 
     It is another object of this invention to provide a blank and resulting preassembled chair unit of a lightweight, high-strength, relatively rigid sheet material which can be produced in various sizes ranging from children&#39;s size to adult size. 
     It is still another object of this invention to provide a preassembled disposable chair which has a handhold specially disposed therein for ease of carrying. 
     It is another object of this invention to provide a preassembled, pop-open chair unit which is ergonomically designed to provide optimum comfort and lumbar (lower back) support for continuous seating over an extended period of time yet is able to safely accommodate a variety of human sizes and weights. 
     It is another object of this invention to provide a blank for a disposable chair, and the preassembled chair unit made from said blank, which can be coated with a variety of coatings such as waterproofing or graphics to render the chair resistant to moisture damage and allowing for extensive areas on the chair for advertising or promotional purposes. 
     It is another object of this invention to provide a blank for a disposable chair which is simple to manufacture, preassemble and use, yet which is sufficiently cheap that the chair may be sold for one-time usage for promotional purposes. 
     It is still another object of the invention to provide a means for retaining a trash bag in association with a disposable chair so that users may conveniently dispose of trash in the chair while at use at concerts, picnics and the like, and which can then be easily disposed of either separately or along with the chair at the end of the event. 
     Still further and other objects of this invention will be evident from the description and drawings. 
     SUMMARY 
     A one-piece blank is die cut from a standard width (for an adult chair) of corrugated cardboard. The blank is generally rectangular with panels defined therein by joined score lines. The lower 10-20% of the blank is separated by parallel cut-out slots into a plurality of optional flaps or base panels which are later folded 180° to be glued to the inner face of adjacent sidewall panels to form a reinforced base perimeter. Approximately half of the vertical balance of the blank forms the sidewalls, and the upper half forms a pair of interconnected seat/back panels. The seat/back panels are delineated from the sidewalls by a generally W-shaped set of score lines. Generally trapezoidal sidewall panels are defined between the W score lines and the optional reinforcing base panels. 
     The blank has a tab at one transverse end which is fastened to the opposite side of the other end of the blank to form in cross-section an enclosed polygon, preferably a modified hexagon of unequal sides. A first of the pair of seat/back panel assemblies is folded down with one or more tabs or flaps frictionally engaging one or more of the sidewall panels. Then the second of the pair of seat/back panel assemblies is folded over the first, and an interlocking tab engages a slot in the first to complete the assembly. 
     In use the seat is oriented with one of the polygon (hexagon) corners forward to provide leg room on either side. A generally triangular or trapezoidal backrest panel is joined to a generally rectangular middle seat panel, and the seat portion is joined in turn to a generally triangular leg panel. The seat/back assembly is ergonomically designed for optimum comfort and lumbar (lower back) support for continuous seating over an extended period of time by having the panels oriented so the leg support is tilted upward from the horizontal, the adjoining middle seat panel is tilted downwardly from the horizontal, and the back panel is inclined backwardly from the vertical, (preferably less than 35°). The combination of the seat/back panels forms in cross-section a multi-planar C-shape concave up and tilted with its imaginary central axis at an acute angle forward from the vertical. 
     Once the end tab is glued to the other end to form the enclosed polygon, the assembly can be folded flat for storage or shipping. A pair of aligned apertures functioning as handholds are placed medially of the upper and lower edges of the blank, preferably in the middle seat panel toward one end thereof. By placing the handhold toward the middle of the blank, the chair blank can be carried without one end (or side) dragging on the ground. Further, the blank will be carried more securely in windy conditions as approximately half of the blank will be secured between an arm and the carrier&#39;s body, and the lower half can be pressed against the user&#39;s leg. 
     The backrest panel is preferably a truncated triangle (trapezoid) so that a generally triangular aperture is formed between it and the rear sidewalls. This provides a space through which a stake can be driven to keep the chair from being blown away by the wind when unoccupied. The stake may be a bare stake, a light pole of some sort, an umbrella pole for sun, shade or rain protection, or the like. Likewise, a refuse bag can be suspended in the hole to provide a handy place for disposal of paper, plastic, cans or glass refuse of the type common at picnics, concerts, beaches, and the like. 
     The chair is lightweight, easy to carry, stores flat and pops open for easy assembly. The solid sidewalls forming the base of the chair provide extensive area for graphics of a promotional or design nature. The sheet material can be any lightweight, high-strength, relatively rigid material such as corrugated cardboard, fiberboard, plastic, light wood (with cloth, plastic or paper webbing to join the panels), and the like. We prefer 350-450 lb test dual arch corrugated cardboard, which may be plasticized (curtain coated) to make it moisture resistant for longer life. The piece blanks can be cheaply and rapidly produced on continuous rotary die-cut presses, for example, a 5&#39; Maramatsu press taking standard 3&#39;×5&#39; sheets. The wastage for the blank shown in FIG. 1 is under about 10%, and the blank may be oriented with its longitudinal axis either parallel or transverse to the long axis of the cardboard sheet, depending on the chair size desired. The blank shown may be scaled in size for children to adult sizes, and lighter weight cardboard may be used for children&#39;s sizes, if desired. Neither set-up nor take-down of the chairs requires tools. The chair is so cheap to make that it can be disposed-of after a single use. Because of its nature, the chair sheet material is ideally suited to be made from recycled material, and again recycled after use. Likewise, the used chair, as garbage, could be used for fuel. 
     Because of the overlapping seat/back assemblage of panels and the hexagonal ergonomic design, the chair structure does not break in extensive normal use. For example, when weight is placed in the center of the seat (on the middle seat panels), the sidewalls are drawn together, rigidifying the structure. On overuse, the chair will gradually collapse, which is a safety feature. In large crowds, such as at rock concerts, some participants become unruly. Because of the cardboard nature of the materials, the chair cannot be used as a deadly weapon. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described below in more detail with reference to the drawings in which: 
     FIG. 1 illustrates the exterior side of a blank for a disposable chair in accordance with this invention; 
     FIG. 2A shows a right elevation of the chair in the flat (knocked-down) assembled form ready for transport or storage; 
     FIG. 2B shows the left elevation of the chair of FIG. 2A; 
     FIG. 2C shows a front elevation of the chair of FIGS. 2A and 2B in the flat condition for storage or transport; 
     FIG. 3 is a plan view of the chair of this invention as set up for use (the front faces the bottom of the page); 
     FIG. 4 is a front elevation of the chair of this invention as set up for use; 
     FIG. 5 is a rear elevation view of the chair of this invention as set up for use; 
     FIG. 6 is a section view along line 6--6 of FIG. 4; 
     FIG. 7 is a section view of the chair of this invention along line 7--7 of FIG. 5; 
     FIG. 8 is a three-quarter front right perspective view of the chair of this invention partially set up with the lower or underneath seat/back panel assembly in position before the upper seat/back assembly is folded thereover; 
     FIG. 9 is a three-quarter front right perspective of the chair of this invention in its completely set-up position after the upper seat/back panel assembly has been folded down and locked in place; 
     FIG. 10 is a three-quarter rear perspective view from the right side of the chair of this invention showing it in its completely set-up condition, and having a portion broken away in order to show the locking tab; and 
     FIG. 11 is an enlarged view of the locking tab inset in the margin of a back rest panel. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following detailed description of the preferred embodiments is by way of illustration and not by way of limitation of the general principles of this invention. 
     Referring now to the drawings, FIG. 1 shows a one-piece blank 1 of the chair of this invention die cut from a sheet of dual arch corrugated 400 lb test cardboard. The side shown facing the viewer in FIG. 1 becomes the exterior of the chair when assembled. As noted, the blank is generally rectangular as defined between top margin 2, 2&#39;, bottom margin 3, rear margin 4 (on the left side of FIG. 1), and assembly flap margin 5 (on the right side of FIG. 1). As noted, these margins have various cut-outs (removed portions) to define the perimeters of various panels as described in more detail below. As seen best in FIG. 1, the assembly flap M is secured to the reverse side of panel D in the area outlined by the dashed line adjacent to the rear margin 4. The assembly flap M may be fastened by glue, staples or other means to the panel D. When so assembled, the chair is then in its knocked-down or pre-setup condition, and the handle apertures S and S&#39; in panels N and Q are aligned for carrying. This is best seen in FIGS. 2A and 2B. This is the shape of the chair for shipping, carrying or storage. 
     The only other panels or flaps which are glued or otherwise secured in the assembly are optional base panels A, B, C and their corresponding base panels A&#39;, B&#39; and C&#39;. These are folded 180° and glued or otherwise secured to the inside face of adjoining vertical wall panels D, E, F, D&#39;, E&#39;, F&#39;, respectively, to form a reinforced base for the chair. All of these reinforcing panels A, B, C, A&#39;, B&#39;, C&#39; panels G, H, and I are optional and may be omitted although we prefer to have them to produce a stronger, more reinforced product. 
     It will also be noted that there is only one locking tab in the preferred embodiment. This is tab Z&#39; formed along the upper margin 2&#39; extending from the edge of backrest panel R. This is inserted into slot Z in the inner backrest panel K as best seen by comparing FIGS. 8, 9 and 10. 
     Returning to FIG. 1, the right side of the chair comprises the assemblage of panels which are identified by A-F and K, N and O (which in the drawing lie on the left). The panels forming the left side of the chair are identified in FIG. 1 for the most part with primes A&#39;-F&#39; (except for individual letter designations for the seat/back assembly overlay panels P, Q and R), and these lie on the right of FIG. 1. The right side and left side of the chair assembly are joined by a front rib or webbing AA of generally rectangular configuration which joins the adjacent front right panel F to the front left panel F&#39; along their common boundary. The width of the front rib or web AA needs only be wide enough to provide a bend in the cardboard to compensate for the multi-layer thickness in the folded condition as best seen in FIG. 2C, and so that the scoring between the front right and front left panels F and F&#39;, respectively, is not so sharp that a tear develops along that juncture under usage or handling conditions. Likewise, there is a rear rib or web BB joining the assembly flap M to the left rear sidewall panel D&#39; which serves the same function. The front and rear rib panels or webs AA and BB are also seen in FIGS. 3, 4, 5, 9 and 10. 
     Inset upwardly from the bottom margin 3 are a pair of double score lines 6, 6&#39; which are generally parallel to the bottom margin 3. As seen, there are a series of relieved portions or cut-outs (30, 31, 32, 33, 34), which serve to define the side margins of the bottom reinforcing panels A, B, C, A&#39;, B&#39; and C&#39;. These bottom panels are folded 180° upwardly to be secured to the inner face of the corresponding panels to which they are attached, panels D, E, F, D&#39;, E&#39; and F&#39;. As seen in FIG. 1, this involves folding &#34;downwardly&#34; (through the plane of the figure paper) so that the hidden face of the panels A-C&#39; are secured to the hidden face of the panels D-F&#39;. This is shown by the arrows CC on the right and left side of FIG. 1. FIGS. 2A, 2B, 2C, 4, 5 and 8 show these base reinforcing panels glued in position along the lower margins of the sidewall panels D-F and D&#39;-F&#39; in dashed lines because they are hidden from the exterior view. FIGS. 6 and 7, being section views, show the panels A-C, A&#39;-C&#39; and M glued in position from an interior view. As noted above, these base panels A-C and A&#39;-C&#39; are optional but are preferred when using untreated corrugated cardboard to make a stronger product. Where it is desired to have a taller chair, the vertical height of these base panels A-C and A&#39;-C&#39; can be reduced. Indeed, the sidewalls D-F and D&#39;-F&#39; can be extended the entire width of the panels A-C and A&#39;-C&#39;  if desired where the material strength permits for the particular lifespan projected for the chair. 
     The balance of the blank shown in FIG. 1 lying between the double score line 6, 6&#39; and the top margin 2, 2&#39; is roughly divided in half with the lower portion defining the two sets of right sidewall panels D-F and left sidewall panels D&#39;-F&#39;. There is a continuous but jointed set of score (fold) lines roughly in the shape of a W, which form left to right are score lines V, W, X, X&#39;, W&#39; and V&#39;. These divide the upper seat/back panel assemblies from the lower sidewall panel assemblies. Note that the sidewall panels are generally trapezoidal. The vertical rear right sidewall panel D is defined between margin 4 and score lines V, 7 and 6&#39;. Center right sidewall panel E is defined between score lines 7, W, 8 and 6&#39;. Front right sidewall panel F is defined between score lines 8, X, front rib AA, and 6&#39;. The rear left vertical sidewall panel D&#39; is defined between score lines 10, V&#39;, rear rib panel BB, and double score line 6&#39;. Center left vertical sidewall panel E&#39; is defined between score lines 9, W&#39;, 10 and 6&#39;. Front level vertical sidewall panel F&#39; is defined between the front rib AA and score lines X&#39;, 9 and 6&#39;. 
     Note that in the upper portion of the rear right side vertical sidewall panel D and the corresponding panel D&#39; are defined triangular panels J and L, respectively, between score lines U, 11 and V (for panel J) and U&#39;, 11&#39; and V&#39; (for panel L). These panels J and L are called backrest support panels, J being for the right side and L being for the left side, and have the function of providing lost motion in movement and flexing of the seat/back panel assemblies as described in more detail below. Also, as noted above, flaps G and I are reinforcing flaps or panels to reinforce the backrest support panels J and L, respectively. They are defined between the double score lines 11 and 11&#39; and the margin edges of the panel, respectively. 
     Double score lines are used when the panel is to be folded over 180° back onto the adjacent panel and secured thereto. Where the panel or flap is folded less than 180°, a single score line is used. 
     The optional panels G and I are preferably glued to the inside face of panels J and L, respectively. The notched margin Y&#39; of panel I interlocks with the notched margin Y in panel K as described in more detail below. 
     Likewise, a triangular flap H is defined from panel K by double score line 12 and the marginal edges. Panels G and H are separated from each other by relieved slot or cut 13. Panel H is infolded and secured to the inside of panel K as an optional reinforcing panel. A preferred securing method is use of glue. Panels J, K and L may be extended into panels G, H and I, respectively, to raise the height of the back support by moving the score lines 11, 12 and 11&#39; toward the apex of the panels G, H and I. 
     The upper portion of the blank 1 comprises a pair of three seat/back panel assemblies, the underneath seat/back (lower) assembly comprising panels K, N and O being joined to the right side vertical sidewall panels DEF along score lines V, W and X. Likewise, the seat/back overlay (upper) panel assembly comprising panels P, Q and R are joined to the left vertical sidewall panel assembly D&#39;, E&#39; and F&#39; along the score lines X&#39;, W&#39; and V&#39;. The lower legrest panel O and upper legrest panel P are generally triangular, and are joined along fold lines 14, 14&#39; with seat panels N and Q, respectively. Seat panels N and Q are generally rectangular and have disposed adjacent score lines W and W&#39;  &#34;stadium&#34;-shaped apertures S and S&#39; which function as handholds. The apertures S and S&#39; are so disposed that they are in alignment when the assembly flap M is glued to the inside of panel D as shown in FIGS. 2A and 2B. The apertures S and S&#39; may be disposed in the legrest panels O and P as seen in FIG. 1. 
     Adjacent the other marginal edge of panel N along fold line 15 is a triangular panel T which serves as a frictional interlock against the upper portion of the inside of panel E&#39; when the chair is in its set-up position. This is best seen in FIGS. 4, 6 and 8. No glue is used on this panel unless the chair is desired to be set up permanently, that is, so it cannot be knocked-down and folded flat. If a permanent installation is desired, then glue may be applied to the face of flap T showing in FIG. 1. When assembled, the score line 15 abuts the score line W&#39; on the inside face of panel E&#39;. 
     The lower (underneath) backrest panel K is trapezoidal and is defined between score lines 16, V, 12 and 2. Likewise, the corresponding upper (overlay) backrest panel R is defined between score lines 16&#39;, V&#39;, margin 12&#39; and margin 2&#39;. As described above, locking tab of flap Z&#39; is defined as an extension of panel R along margin 2&#39;. 
     The upper portions of FIGS. 2A and 2B show how panels G, H and I are folded over and glued to the inside faces of panels J, K and L, respectively. These folded over and glued panels are also identified in FIGS. 3-7, 8 and 10. Note particularly in FIG. 10 how the notched margin Y in panel K interlocks with the notched margin Y&#39; of panel I. This provides excellent locking support for the back. The marginal edge of panels O and P are identified with the numerals 17 and 17&#39;, respectively (FIGS. 1 and 10). 
     By following through on FIGS. 3-7, the various score and panel numbers and letters, the working relationship of the various panels to each other can be seen. Note particularly in FIGS. 3, 5, 6, 7 and 10 that the score lines 11, 11&#39; and 12 form a triangular opening into which a garbage bag 19 and/or a stake or umbrella 20 can be inserted. The stake 20 can be the support pole of an umbrella (be it for rain or sun shade), a light pole or the like. Alternatively, panel H is not secured to panel K and an oval hole 27 (FIG. 1) provided therein to receive the stake 20 so that the chair is secured against movement. 
     Looking now in particular at FIGS. 2A, 2B, 2C, 8, 9 and 10, the following steps are employed to set up the chair. First, the unit shown in FIGS. 2A-2C is popped open by pulling apart the two sides of the unit at the handle openings S and S&#39; to form a three-dimensional base, the sidewalls in horizontal section view forming a modified hexagon with one acute angle facing forward, that being the angle formed between the vertical front right and left sidewall panels F and F&#39;. As best seen in FIGS. 8 and 9, the front apex is the front rib panel or web AA joining the sidewall panels F and F&#39;. The lower seat portion formed by the three panels K, N and O are then folded down along the score lines V, W and X as indicated in FIG. 8. The flap T is folded down along score line 15 so that its outer surface contacts the inner surface of panel E&#39;. In the process of folding down, the panel J will flex outwardly along the score line U away from the rear right side vertical sidewall panel to permit lost motion in the folding. One or more of the upper seat/back assembly panels P, Q and R may also flex during this step. The notches Y along the marginal edge 2 of panel K will then engage the notches Y&#39; in panel I which has been secured to the inner face of panel L. Then the upper seat/back panel assembly, panels R, Q and P, are folded down over the lower seat/back panel assembly (panels K, N and O), and the tab Z&#39; is secured into the slot Z. In this step, the panel L will likewise flex along score line U&#39; to permit lost motion in the folding. FIG. 9 shows the completed folding of the upper seat panel assembly, panels R, Q and P. 
     As best seen in FIG. 10, the tab Z&#39; is then firmly locked in the slot Z in the lower seat/back assembly panel K. The panels J and L have returned to a position coplanar with the rear right and left vertical sidewall panels D and D&#39;, respectively. Note the notch 24 in tab Z&#39; faces downwardly; when the user sits in the chair, his or her weight forces the panels Q and R downwardly engaging the end 25 of slot Z in the notch, positively locking panel R against panel K. 
     In use, when the user sits on the chair putting weight on the seat panel Q, the flex panels J and L actually flex inward, and the notches Y and Y&#39; are more firmly interlocked. 
     To knock the chair down for storage or transport, the tab Z&#39; is slipped upwardly and out of the slot Z, the upper seat/back panel assembly is raised, the lower seat back assembly is then lifted to a vertical position, and the two sides brought together so the assembly is again in a flat configuration as shown in FIGS. 2A through 2C. 
     If a permanent installation is desired, the face of tab T (as seen in FIG. 1) may be glued or otherwise fastened to the inside of panel E&#39;. Likewise, the tab Z&#39; can be glued to the inner face of panel J. Double-sided tape or Velcro fastening strips may be employed. 
     It is also possible to provide an interlock of tab T (or a modification of tab T) in the sidewalls of panel E&#39; by providing a slot in panel E&#39;. Likewise, tab T could be interlocked into panel Q by providing a slot therein, if desired. However, we have found that this is not necessary for occasional or short-term use of the disposable chair of this invention. We have found that in operation, the weight placed on the chair back panel R tends to urge the lower panel N to the left (as seen in FIG. 10; to the right in FIG. 9), thus urging the face of tab T against the inside of the vertical sidewall E&#39;. This provides a sufficient frictional interlock. 
     Likewise, panels E and E&#39; can be vertically shortened by the extension of slots 30, 31, 33 and 34 (defining the side margins of panels B and B&#39;) so that upon folding upward, a folded-over edge of the bottom of panels B and B&#39; (the folded-over edge being identified in FIG. 1 as formed by fold line 21, 21&#39;) provides an additional vertical support for the side edges of panel N along score lines W and 15. In this embodiment, the flap T may be omitted. In this embodiment, as best seen in FIG. 10, panel E would only extend downwardly as fas as line 22 unless there was an extension of panels B and B&#39; lower than the edge of the blank 3 as shown in FIG. 1. 
     FIG. 11 shows an enlarged view of an alternate embodiment of locking tab Z&#39; which is inset along margin 21 of panel R. The corresponding slot Z would be moved inwardly in panel K away from the score line V. In this embodiment panels R and K may be widened rather than tab Z&#39;  being inset, and wastage is reduced. If the seat/back panels are widened, then all panels D-F and D&#39;-F&#39; must be widened proportionately. 
     Various other modifications and additions to the chair of this invention may be made. While it is seen that the angles from the vertical of the various panels which form the seat/back assembly (panels K, N, O, R, Q and P) are ergonomically designed to provide a most comfortable seating arrangement with excellent lumbar support, it can be appreciated that the angles may be varied somewhat depending on the intended use. For example, the backrest panels R and K may be inclined further back for a beach-type chair to provide more sun exposure. Likewise, the width of panels E, E&#39;, N and Q can be changed or eliminated entirely as desired. When the panels E and E&#39; are either eliminated or reduced to a small webbing analogous to the webbing AA or BB, then the seat panels N and Q are likewise reduced, and the leg panels O and P are enlarged. In these cases, the tab T may be eliminated, and the larger tab 22 as shown best in FIG. 1 may be employed. In addition, it should be understood that the flap 26 may be employed in the configuration of the chair as shown in FIGS. 1-10. This would provide additional support for the leg panel P. From the ergonomic viewpoint, for greatest seating comfort we prefer keeping substantially seat panels N and Q, having the backrest panels K and R oriented at no more than 35° back from the vertical, and the legrest panels O and P at no less than 5° up from the horizontal. As shown in phantom in FIGS. 9 and 10, a locking tab Z&#39; may be formed adjacent the margin of upper seat panel Q and/or legrest panel P which interlocks in corresponding slot Z in lower seat panel N and/or legrest panel O. 
     It should be understood that various modifications within the scope of this invention can be made by one or ordinary skill in the art without departing from the spirit thereof. For example, just as panels B and B&#39; can be extended so that upon folding 180° to be secured to the inside of panels E and E&#39;, respectively, so panels A, A&#39; and/or C, C&#39; can be extended to meet fold lines U, U&#39; or X, X&#39;, respectively, to provide added support to the legrest and/or backrest panels. We therefore wish our invention to be defined by the scope of the appended claims as broadly as the prior art will permit, and in view of this specification if need be.