Abstract:
A foldable, recyclable chair for stadium event patrons. First and second longitudinal score lines divide a pre-scored, pre-cut blank into left and right longitudinally-extended, mirror-image sections joined by a central section. The central section comprises five quadrilateral panels joined in tandem at transverse score lines, the topmost comprising two triangular panels joined by a trapezoidal panel. The left and right sections each comprise, in descending order, an upper flap panel, a rectangular array of triangular panels defined by intersecting diagonal score lines that join opposite corners of the rectangular array; a first trapezoidal panel that is bounded by a diagonal score line; a second trapezoidal panel joined to the first along the diagonal score line boundary thereof; and a rectangular panel joined to a lower end portion of the central section and separated from the second trapezoidal panel by a transverse cut line. The blank folds to form a chair that opens for sitting and collapses for storage. In a second version, the central section comprises seven panels joined in tandem at transverse score lines. A left longitudinal section includes an upper, four-panel assembly and a lower, two-panel assembly. The right longitudinal section is a mirror-image twin of the left.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/628,276, with filing date Nov. 17, 2004. 

   STATEMENT REGARDING GOVERNMENT SPONSORED RESEARCH 
   None 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to economical, lightweight, recyclable and rapidly set up chairs suitable for stadium and other event seating, and more particularly to collapsible, disposable chairs that can be assembled from a single die-cut, foldable, scored blank of corrugated fiberboard or like generally planar recyclable material. 
   2. Prior Art 
   Spectators at stadium sporting events and concerts, horse and auto races, and other large gatherings often desire to have a portable chair that will provide a clean, dry and comfortable place to sit and that thereafter will collapse for compact storage for use again later or for disposal after one or more uses. To achieve light weight and low cost so as to be sufficiently inexpensive to be disposable, and preferably in a manner in which its materials can be recycled, such chairs have been assembled from foldable blanks of sheet material such as cardboard or other fiberboard and the like. Exemplary of the art in this field are the following patents: Klein U.S. Pat. No. 4,085,970; Geneve et al. U.S. Pat. No. 4,556,253; Calco U.S. Pat. No. 4,648,658; Volpe U.S. Pat. No. 4,811,987; Scalisi U.S. Pat. No. 4,713,774; Scalisi et al. U.S. Pat. No. 4,984,848; Smith U.S. Pat. No. 5,860,704; Ribot U.S. Pat. No. 5,580,131; and Howard et al. U.S. Pat. No. 5,795,027. By printing advertising on such chairs and providing an event chair to each attendee who requests one, stadium proprietors or event sponsors can acquire advertising revenue and at the same time obviate the need for event attendees to bring their own event chairs; see, for instance, Scalisi et al., U.S. Pat. No. 4,813,744 at col. 14. A significant portion of the cost of providing event chairs has been the time and labor involved in preparing the chairs for use, as the foldable blanks of the prior art event chairs have been less than ideal in that regard. 
   SUMMARY OF THE INVENTION 
   A chair foldable between a closed, collapsed storage position and an open, extended sitting position is formed by folding a single pre-cut, pre-scored blank of cardboard, fiberboard or the like. In its open, extended sitting position, the chair may be seen to include a rectangular seat, a rectangular seat back pivotally joined to a rear portion of the seat, and, triangular left and right chair sides that join the left and right sides of the seat back to the left and right sides of the seat, respectively. The left and right chair sides are each bisected by a fold or score line that extends from the apices of their triangles to an opposite side thereof, thereby permitting the seat back and seat alternately to be moved apart and together in bellows fashion through 90 degrees of pivoting rotation, corresponding to the open, extended sitting position and the collapsed position, respectively. The chair is assembled by folding a single, corner-truncated, generally rectangular body having longitudinal length preferably somewhat greater than transverse width. The term “corner-truncated” is intended to indicate that the upper left and right rectangular corner areas and lower left and right rectangular corner areas of the body are cut away from what would otherwise present an overall rectangular body outline. The body is divided into three longitudinally-extended sections of about equal transverse width by left and right longitudinal score lines—namely, a central longitudinal section; a left longitudinal section that is joined to the central longitudinal section at the left longitudinal score line; and a right longitudinal section that is joined to the central longitudinal section at the right longitudinal score line. The central section extends from an upper body margin down to a lower body margin and comprises a series of panels, denoted in descending order as trapezoidal panel (U) having a lower end joined to an upper end of panel (T) at a transverse score line  86 , panel (T) joined to an upper end of panel (A) at transverse score line  20 , panel (A) joined at a lower end to panel (B) at a transverse score line  18 , and panel (B) joined to a panel (C) at a double transverse score line  22 . Joined to left and right ends of panel (U) along diagonal score lines are triangular panels (V) and (W) such that panels (U), (V) and (W) together comprise a rectangle. The left section extends from the upper body margin down to a lower body margin and comprises a series of panels, denoted in descending order as panels (R), triangular panel (L) joined at an upper end to a lower end of panel (R) at a transverse score line  20 , panel (L) being part of a quartet of panels—i.e., triangular panels (L), (J), (N) and (P)—having a common vertex that in unfolded, flat conformation together comprise a rectangular section (L, J, N, P); a lower end of the rectangular section (L, J, N, P)—namely, panel (N)—joined at a transverse score line  18  to an upper end of a trapezoidal panel (H); a trapezoidal panel (F) joined to panel (H) at a diagonal score line  41 ; and panel (D) separated from a lower end of panel (F) by a lower left cut line  70  and joined at the left longitudinal score line to panel (C). A diagonal score line  48  is a common end and line of joinder of panel (N) to panel (P) and of panel (J) to panel (L) A diagonal score line  44  is a common end and line of joinder of panel (J) to panel (L). The diagonal score line  48  intersects diagonal score line  44  at the common vertex of panels (L), (J), (N) and (P). The right longitudinal section is symmetrically disposed with respect to the left longitudinal section and comprises corresponding panels in descending order. That is, the right longitudinal section extends from the upper body margin down to a lower body margin and comprises a series of panels, denoted in descending order as panel (S), triangular panel (M) joined at an upper end to a lower end of panel (S) at a transverse score line  20 , panel (L) being part of a quartet of panels (triangular panels (M), (Q), (O) and (K) having a common vertex) that in unfolded, flat conformation together comprise a rectangular section (M, Q, O, K); a lower end of the rectangular section (M, Q, O, K)—namely panel (O)—joined at a transverse score line  18  to an upper end of a trapezoidal panel (I); a trapezoidal panel (G) joined to panel (I) at a diagonal score line  42 ; and panel (E) separated from a lower end of panel (G) by a lower right cut line  72  and joined at the right longitudinal score line to panel (C). A diagonal score line  50  is a common end and line of joinder of panel (O) to panel (Q) and of panel (K) to panel (M); a diagonal score line  46  is a common end and line of joinder of panel (O) to panel (K) and panel (Q) to panel (M). Diagonal score line  46  intersects diagonal score line  50  at the common vertex of panels (M), (Q), (O) and (K). Preferably, a lower end of panel (C) has a tab extension adapted for insertion and retention within a slot centrally disposed and aligned on transverse score line  80 . Adjacent panels joined at score lines are foldable with respect to each other. Accordingly, by a series of steps illustrated in the accompanying figures, the blank can be folded to assemble a recyclable event chair, wherein panels (B), (U), (V), (W), (H), (I), (F), (G), (C), (D) and (E) form the seat, panels (L), (J), (P) and (N) form the left side, panels (M), (Q), (O) and (K) form the right side, and panels (A), (R), (S) and (T) form the back of the chair. An exterior surface of panel (B) provides a suitable surface for a printed advertisement if desired. 
   The blank preferably further comprises a left trapezoidal flange panel (X) joined to a left end of panel (P) at a longitudinal score line  92  and a trapezoidal right flange panel (Y) joined to a right end of panel (Q) at a longitudinal score line  94 , wherein the flange panels (X) and (Y) each have diagonal upper margins that are parallel to diagonal score lines  48  and  50 , respectively. When the blank is folded, flange (X) partially overlies panel (H) and flange (Y) partially overlies panel (G), thereby forming part of the seat of the chair. 
   In an alternate embodiment of the invention, a pre-cut, pre-scored blank is provided for a chair foldable between a closed, collapsed storage position and an open, extended sitting position. The blank, when completely unfolded to a flat conformation, comprises a foldable, elongated body that extends longitudinally from an upper end margin to an opposite lower end margin and transversely from a left margin to a right margin. The blank has a central, longitudinally-extended section that includes a rectangular panel (A), a rectangular panel (B) joined to a lower end of panel (A) along a first transverse score line; a rectangular panel (C) joined to a lower end of panel (B) along a second transverse score line; a rectangular panel (D) joined to a lower end of panel (C) along a third transverse score line; a rectangular panel (E) joined to panel (D) along a fourth transverse score line; a rectangular panel (F) joined to a lower end of panel (E) along a fifth transverse score line; and a trapezoidal panel (G) joined to a lower end of panel (F) along a sixth transverse score line. 
   An upper left chair side/bottom assembly is joined to a left end of panel (B) at a first longitudinal score line, extends leftward from panel (B), and includes a right triangular panel (H), a trapezoidal panel (J), a right triangular panel (I) and a trapezoidal panel (K). The base of panel (I) is joined to a left end of panel (B) at a first longitudinal score line. The hypotenuse of panel (I) is also the hypotenuse of panel (H) to which it is joined along a diagonal score line that is preferably a double score line. An upper end of panel (I) is joined to a lower end of panel (K) at the first transverse score line. Panel (H) is further bounded by a lower left margin that extends leftward and upward from the point of intersection of the second transverse score line with the left longitudinal score line, which lower margin is further extended to form a lower margin of panel (J). Panel (J) is joined to a left end of panel (H) along a diagonal score line that is directed upward and rightward to the point of intersection of panels (H) and (I) with panel (K). 
   The second embodiment further includes an upper right chair side/bottom assembly that is joined to a right end of panel (B) at a second longitudinal score line, extends rightward from panel (B), and includes a right triangular panel (L), a trapezoidal panel (N), a right triangular panel (M) and a trapezoidal panel (O). The base of panel (M) is joined to a right end of panel (B) at a second longitudinal score line. The hypotenuse of panel (M) is also the hypotenuse of panel (L) to which it is joined along a diagonal score line that is preferably a double score line. An upper end of panel (M) is joined to a lower end of panel (O) at the first transverse score line. Panel (L) is further bounded by a lower right margin that extends rightward and upward from the point of intersection of the second transverse score line with the right longitudinal score line, which lower margin is further extended to form a lower margin of panel (N). Panel (N) is joined to a right end of panel (L) along a diagonal score line that is directed upward and leftward to the point of intersection of panels (L) and (M) with panel (O). 
   The second embodiment also includes a lower left chair side/back assembly that is joined to a left end of the panel (C) at the first longitudinal score line and extending from the second transverse score line to the third transverse score line. The lower left chair side/back assembly includes a right triangular panel (P) bounded by the first longitudinal score line, a ninth transverse score line collinear with the third transverse score line and extending leftward therefrom a distance about equal to the length of the left top margin, and a left diagonal margin that extends from the leftmost extremity of the ninth transverse score line to the junction of the second transverse score line with the first longitudinal score line. This assembly further includes a trapezoidal panel (Q) having an upper end joined to a lower end of panel (P) at a ninth transverse score line, and bounded by a left margin that extends from the junction of the ninth transverse score line with the left diagonal margin downward below the level of the fourth transverse score line but well above the level of the fifth transverse score line, a longitudinally-directed lower left cut line that extends about the same length as the left margin below the fourth transverse score line and a left bottom end that extends leftward from the lowermost point of said cut line to the lowermost point of said left margin. 
   The second embodiment still further includes a lower right chair side/back assembly that is joined to a right end of the panel (C) at the second longitudinal score line from the second transverse score line to the third transverse score line. The lower right chair side/back assembly includes a right triangular panel (R) bounded by the first longitudinal score line, a tenth transverse score line collinear with the third transverse score line and extending rightward therefrom a distance about equal to the length of the right top margin, and a right diagonal margin that extends from the rightmost extremity of the tenth transverse score line to the junction of the second transverse score line with the second longitudinal score line. This assembly further includes a trapezoidal panel (S) having an upper end joined to a lower end of panel (R) at a tenth transverse score line, and bounded by a right margin that extends from the junction of the tenth transverse score line with the right diagonal margin downward below the level of the fourth transverse score line but well above the level of the fifth transverse score line, a longitudinally-directed lower right cut line that extends about the same length as the right margin below the fourth transverse score line and a right bottom end that extends rightward from the lowermost point of said cut line to the lowermost point of said right margin. As in the case of the first embodiment, adjacent ones of said panels are foldable about said score lines with respect to one another. 
   The accompanying figures indicate the manner in which the blank of the second embodiment is to be folded to assemble a recyclable event chair. When so folded, panels (B) and (C) form the back, panels (L), (M), and (R) form the left side, panels (H), (I) and (P) form the right side, and the remainder of the panels form the seat of the chair. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top plan view of a pre-folded, pre-cut blank of sheet material that is foldable into a collapsible chair according to a first embodiment of the present invention, shown flat and unfolded; 
       FIGS. 2-9  illustrate a sequence of steps to convert the blank of  FIG. 1  into a collapsible chair: 
       FIG. 2  is a top plan view thereof that shows panels (V) and (W) folded over onto panel (U); 
       FIG. 3  is a top plan view thereof that shows panels (P) and (L) folded over onto panels (N) and (J), panels (R) and (S) folded onto panel (A), and panels (M) and (Q) folded onto panels (K) and (O), respectively; 
       FIG. 4  is a top plan view thereof that shows panels (U) and (T) folded over onto Panels (R) and (S), and panels (U), (V) and (W) folded onto panel (B); 
       FIG. 5  is a frontal perspective view thereof that shows panel (T) partially folded to an upstanding position, and panels (P) and (L) partially folded onto panels (N) and (J), panels (Q) and (M) partially folded onto panels (O) and (K), and panels (F) and (G) partially folded onto panel (B), respectively; 
       FIG. 6  is a frontal perspective view thereof that shows the completion of the partial folding of  FIG. 5 ; 
       FIG. 7  is a frontal perspective view thereof that shows panels (D) and (E) folded onto panel (C); 
       FIG. 8  shows panels (C), (D) and (E) folded onto panels (R) and (S), thereby completing conversion of the blank into a chair in an open, extended position; and 
       FIG. 9  is a side elevational view of the same chair in a collapsed position; 
       FIG. 10  is a top plan view of a pre-folded, pre-cut blank of sheet material that is foldable into a collapsible chair according to a second embodiment of the invention; 
       FIGS. 11-20  illustrate a sequence of steps to convert the blank of  FIG. 10  into a collapsible chair: 
       FIG. 11  is a top plan view thereof that shows panel (C) folded onto panel (B), panel (D) folded onto panel (A), panel (P) folded onto panel (I), panel (Q) folded onto panel (K), panel {circle around (R)} folded onto panel (M), and panel (S) folded onto panel (O); 
       FIG. 12  is a top plan view thereof that shows panel (D) folded back onto panel (C); 
       FIG. 13  is a top plan view thereof that shows panel (H) folded onto panel (P) and panel (J) folded onto panel (Q); 
       FIG. 14  is a top plan view thereof that shows panel (L) folded onto panel (R) and panel (N) folded onto panel (S); 
       FIG. 15  is a top perspective view thereof that shows panels (H) and (L) folded to partially upstanding positions while panel (A) remains in place; 
       FIG. 16  is a top perspective view thereof that shows panels (J) and (N) partially folded into mating alignment to begin formation of a chair bottom, panel (Q) beginning to be folded behind panels (J) and (N), panel (S) beginning to be folded behind panel (Q); 
       FIG. 17  is a top perspective view thereof that shows panel panels (J) and (N) folded into planar alignment, panel (Q) folded behind panels (J) and (N), panel (S) beginning to be folded behind panel (Q), and panels (K) and (O) beginning to be folded behind panel (A); 
       FIG. 18  is a top perspective view thereof that shows panel (A) folded up directly behind panels (S) and (Q); 
       FIG. 19  is a top perspective view thereof that shows panel (D) folded over onto panels (J), (N) and (Q) and panels (K) and (O) extended and ready for folding up behind upstanding panel (A); 
       FIG. 20  is a top perspective view thereof that shows, after panel (K) has been folded behind panel (A) and panel (O) has been folded behind panel (K), panel (E) has been folded behind panel (K), while panels (G) and (F) remain extended rearwardly thereof; 
       FIG. 21  is side perspective view thereof showing panels (F) and (G) being tucked up in between panels (A) and (K); 
       FIG. 22  is a frontal perspective view thereof, after completion of the step shown in  FIG. 21 , showing the complete conversion of the blank into a collapsible chair in an open, extended position. 
       FIG. 23  is a side elevational perspective view of the chair of  FIG. 20  shown partially collapsed. 
   

   Like numerals designate similar components and aspects of the invention throughout the several figures. Panel designations shown parenthetically refer to adjacent panels hidden from view; for instance, (D) in conjunction with (Q) indicates that panel (D) has been folded over onto panel (Q). The terms “left” and “right”, and “upper” and “lower,” refer to the left and right sides and the upper and lower portions of the blanks  10  and  200  as depicted in  FIGS. 1 and 10 , respectively. 
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The chair of the present invention is formed from a single die-cut, foldable, scored blank  10  of corrugated fiberboard or like generally planar recyclable material. The terms “scored,” “score line” and “fold line” are here used interchangeably to generally describe a location that has been pre-folded or marked with lines, grooves, scratches or notches. As shown in  FIG. 1 , blank  10  is comprised of planar material that has the overall outline of a rectangle that is truncated at each of its four corners. That is, a rectangular, upper left corner area has been removed adjacent to a left end of the triangular, left rear seat top underflap panel (V), the left side of the rectangular, inner back panel (T), and an upper end of the rectangular, left upper flap panel (R); a rectangular, upper right corner area has been removed adjacent to a right end of the triangular, right rear seat top underflap panel (W), a right end of panel (T), and an upper end of the rectangular, right upper flap panel (S); a rectangular, lower left corner area has been removed adjacent to a lower end of trapezoidal upper left seat liner panel (H), a left end of the trapezoidal, lower left seat liner panel (F) and a left end of the rectangular, left cover flange panel (D); and a rectangular, lower right corner area has been removed adjacent to a lower end of the trapezoidal, upper right seat liner panel (I), a right end of the trapezoidal, lower right seat liner panel (G) and a right end of the rectangular, right cover flange panel (E). The blank  10  extends longitudinally from an upper end margin  25  to a lower end margin  31  and transversely from a left margin  29  to a right margin  31 . The blank  10  is divided into three longitudinally-extended sections of about equal transverse width by a left longitudinal score line  16  and a right longitudinal score line  14 —namely, a central longitudinal section; a left longitudinal section that is joined to the central longitudinal section at the left longitudinal score line  16 ; and a right longitudinal section that is joined to the central longitudinal section at the right longitudinal score line  14 . The blank  10  includes the following transverse score lines: a central transverse score line  18  centrally disposed between the upper margin  25  and the lower margin  27  and extending the entire transverse width of the blank  10 ; a lower transverse score line  22  below the central transverse score line  31  and extending from the left longitudinal score line  16  to the right longitudinal score line  14 ; an upper transverse score line  20  above the central transverse score line  31  and extending entirely across the blank  10  from the left margin  29  to the right margin  31 ; and a top transverse score line  80  above the upper transverse score line  20  and extending across the central longitudinal section only from the left margin  29  to the right margin  31  thereof. The distances between the transverse score lines  18 ,  20 ,  22 ,  80  are all substantially equal and equate to the front-to-rear dimension of the seat of the chair. The lower transverse score line  22  is preferably a double score line to facilitate the folding of lower portions of the blank [panels (C), (D), (E)] in forming the chair seat. The blank  10  also has diagonal score lines as well as cut lines, which are discussed below in connection with the description of the individual panels thereof. 
   The central longitudinal section includes at its uppermost end a rectangular area comprised of trapezoidal panel (U) joined on its left along a seventh diagonal score line  82  to triangular underflap panel (V) and joined on its right to triangular underflap panel (V) along an eighth diagonal score line  84 . Panel (U) is joined to an upper end of rectangular panel (T) along the top transverse score line  80 . The left margin  29  of the triangular underflap panel (V) is collinear with the left longitudinal score line  16 , as is a left, upper cut line  30  that separates the left end of the rectangular panel (T) from the left-adjacent panel (R). Likewise, the right margin  29  of triangular panel (V) is collinear with the right longitudinal score line  16 , as is an upper right cut line  32  that separates the right end of the panel (T) from the right-adjacent panel (S). A lower end of panel (T) is joined along the upper transverse score line  20  to an upper end of a rectangular, outer back panel (A). A lower end of panel (A) is joined along the central transverse score line  38  to an upper end of a rectangular seat base panel (B). A lower end of panel (B) is joined along the lower transverse score line  22  to an upper end of a rectangular seat cover panel (C). Thus, panel (V) is bounded by a left margin  29 , an upper margin  25  and a seventh diagonal score line  82 ; panel (U) is bounded by the upper margin  25 , an eighth diagonal score line  84 , and the top transverse score line  80 ; the panel (T) is bounded by the top transverse score line  80 , the right margin  31  and the collinear upper right cut line  32 , the upper transverse score line  20 , the upper left cut line  30  and the left margin  29  with which it is collinear; the panel (A) is bounded by the upper transverse score line  20 , the right longitudinal score line  14 , the central transverse score line  38 , and the left longitudinal score line  16 ; the panel (B) is bounded by the central transverse score line  38 , the right longitudinal score line  14 , the lower transverse score line  22 , and the left longitudinal score line  16 ; and the panel (C) is bounded by the lower transverse score line  22 , the right longitudinal score line  14 , the lower margin  27 , and the left longitudinal score line  16 . 
   Proceeding from upper margin to lower margin, the left longitudinal section includes a rectangular, left upper flap panel (R) bounded by the upper transverse score line  20 , the left margin  29 , the upper margin  25  and the left upper cut line  30 ; a triangular, upper, inner left side panel (L) bounded by the upper transverse score line  20 , the third diagonal score line  44 , and the fifth diagonal score line  48 , said panel (L) being joined to a lower end of panel (R) along the upper transverse score line  20 ; a triangular outer left side panel (J) bounded by the left longitudinal score line  16 , the third diagonal score line  44 , and the fifth diagonal score line  48 , said panel (J) being joined to panel (A) along the left longitudinal score line  16 , and joined to panel (L) along a fifth diagonal score line  48 ; a triangular, lower, outer, left side panel (N) bounded by the central transverse score line  18 , the fourth diagonal score line  46 , and a sixth diagonal score line  50 , said panel (N) being joined to panel (J) along a third diagonal score line  44 ; a triangular, lower, inner left side panel (P) bounded by the left margin  29 , the third diagonal score line  44 , and the fifth diagonal score line  48 , said panel (P) being joined to panel (L) along the third diagonal score line  44  and to panel (N) along the fifth diagonal score line  48 ; a trapezoidal upper left seat liner panel (H) bounded by the left margin  29 , the central transverse score line  18 , and the first diagonal score line  40 ; a trapezoidal, lower left seat liner panel (F) bounded by the lower left cut line  70  that is collinear with the lower transverse score line  22 , the left margin  29 , the first diagonal score line  40 , and the right left longitudinal score line  16 , said panel (F) being joined to a left end of panel (B) along the left longitudinal score line and to a right end of panel (H) along the first diagonal score line  40 ; and a rectangular left cover flange panel (D) bounded by the lower margin  27 , the left margin  29 , the lower left cut line  70  that is collinear with the lower transverse score line  22 , and the left longitudinal score line  16 . 
   Similarly, the right longitudinal section includes a rectangular, right upper flap panel (S) bounded by the upper transverse score line  20 , the right margin  31 , the upper margin  25  and the right upper cut line  32 ; a triangular, upper, inner right side panel (M) bounded by the upper transverse score line  20 , the fourth diagonal score line  46 , and the sixth diagonal score line  50 , said panel (M) being joined to a lower end of panel (S) along the upper transverse score line  20 ; a triangular outer right side panel (K) bounded by the right longitudinal score line  14 , the fourth diagonal score line  46 , and the sixth diagonal score line  50 , said panel (K) being joined to panel (A) along the right longitudinal score line  14 , and joined to panel (M) along the sixth diagonal score line  50 ; a triangular, lower, outer, right side panel (O) bounded by the central transverse score line  18 , the fourth diagonal score line  46 , and a sixth diagonal score line  50 , said panel (O) being joined to panel (K) along the fourth diagonal score line  46 ; a triangular, lower, inner right side panel (Q) bounded by the right margin  31 , the fourth diagonal score line  46 , and the sixth diagonal score line,  50  said panel (Q) being joined to panel (M) along the fourth diagonal score line  46  and to panel (O) along the sixth diagonal score line  50 ; a trapezoidal upper left seat liner panel (I) bounded by the right margin  31 , the central transverse score line  18 , and the second diagonal score line  42 ; a trapezoidal, lower right seat liner panel (G) bounded by the lower right cut line  72  that is collinear with the lower transverse score line  22 , the right margin  31 , the second diagonal score line  42 , and the right longitudinal score line  14 , said panel (G) being joined to a right end of panel (B) along the right longitudinal score line  14  and to a left end of panel (I) along the second diagonal score line  42 ; and a rectangular right cover flange panel (E) bounded by the lower margin  27 , the right margin  31 , the lower right cut line  72  that is collinear with the lower transverse score line  22 , and the right longitudinal score line  14 . 
   Preferably, the blank  10  further includes a trapezoidal, inner left side flange panel (X) joined to a left end of the lower, inner left side panel (P) at the third longitudinal score line  92 , and a trapezoidal lower, inner right side flange panel (Y) joined to a right end of the lower, inner right side panel (Q) at a fourth longitudinal score line  94 . Each of the flange panels (X, Y) extends longitudinally a distance coextensive with the panels (P, Q) to which they are joined, and said panels (X, Y) have diagonal top margins  52 ,  58  parallel to the fifth and fourth diagonal score lines  48 ,  46 , respectively. The flange panels (X, Y) are desirable in that, once the blank  10  is folded to form a chair, they provide rounded surfaces instead of cut, ragged ends where the inner surfaces of the chair sides rest against the seat of the chair. 
     FIGS. 2 through 8  illustrate the manner in which the blank  10  is folded to form a chair. Referring to  FIG. 2 , underflap panels (V) and (W) are folded onto panel (U) about the seventh and eighth diagonal score lines  82 ,  84 . Panels (P) and (L) are folded about the fifth diagonal score line so that panel (P) overlies panel (N), panel (L) overlies panel (J) and panel (R) overlies panel (A); see  FIG. 2 . Panel (Q) and panel (M) are folded about the sixth diagonal score line  50  so that panel (Q) overlies panel (O), panel (M) overlies panel (K) and panel (S) overlies panel (A); see  FIG. 3 . Panel (T) is folded about the upper transverse score line  20  so that panel (T) overlies panel (R) and panel (S), and panel (U), panel (V) and panel (W) all overlie panel (B); see  FIG. 4 . Panel (F) and panel (G) are simultaneously folded about the left and right longitudinal score lines  14 ,  16 , respectively, so that said panels overlie panel (B), while at the same time panel (A) is folded up to an upstanding position about the central transverse score line  18 , thereby causing panel (H) and panel (I) to fold inward and downward about the first and second diagonal score lines  40 ,  41  and to overlie panel (G) and panel (G), respectively; see  FIGS. 5 and 6 . Panel (D) is then folded about the left longitudinal score line ( 16 ) and panel (E) is folded about the right longitudinal score line ( 14 ) so that both panels overlie panel (C); see  FIG. 7 . Panel (C) [carrying with it underfolded panel (D) and panel (E)] is folded about the lower transverse score line  22  so that said panels overlie panel (B) and then the tab extension  27 A of panel (C) is inserted into the slot  91 ; see  FIG. 8 . As illustrated in  FIG. 9 , the chair may be collapsed for carrying or storage by pivoting the back toward the seat, which causes the sides to extend triangularly outward. Handle means  201  may be attached to panel (A) at the upper transverse score line  20  for carrying the chair, which may be something as simple as a loop of cord. 
     FIG. 10  depicts a pre-cut, pre-scored blank  200  of an alternative embodiment of the invention, comprised of recyclable, planar material, and shown unfolded to a flat conformation. The blank  200  comprises a central, longitudinally-extended body  112  that extends from an central, upper margin  125  to a central, lower margin  127 , an upper left chair side/bottom assembly  114  and a lower left chair side/back assembly  180  joined to a left side of the central body  112  along a first longitudinal score line  116 , and an upper right chair side/bottom assembly  150  and a lower right chair side/back assembly  198  joined to a right side of the central body  112  along a second longitudinal score line  152 . From the top, in descending order, the central body  112  includes a rectangular panel (A) bounded by a first transverse score line  100  that extends from the first longitudinal score line  116  to the second longitudinal score line  152 , a central, upper margin  125  parallel to said score line, a left upper cut line  130  that extends from the central, upper margin  125  to the first transverse score line  100  and is collinear with the first longitudinal score line  116 , and a right upper cut line  162  that extends from the central, upper margin  125  to the first transverse score line  100  and is collinear with the second longitudinal score line  152 ; a rectangular panel (B) bounded by the first transverse score line  100 , the first and second longitudinal score lines  116 ,  152 , and a second transverse score line  102  that extends from the first longitudinal score line  116  to the second longitudinal score line  152 ; a rectangular panel (C) bounded by the second transverse score line  102 , the first and second longitudinal score lines  116 ,  152 , and a third transverse score line  104  that extends from the first longitudinal score line  116  to the second longitudinal score line  152 ; a rectangular panel (D) bounded by the third transverse score line  104 , the first and second longitudinal score lines  116 ,  152 , and a fourth transverse score line  106 , that extends from the first longitudinal score line  116  to the second longitudinal score line  152 ; a rectangular panel (E) bounded by the fourth transverse score line  106 , the first and second longitudinal score lines  116 ,  152  and a fifth transverse score line  108  that extends from the first longitudinal score line  116  to the second longitudinal score line  152 ; a rectangular panel (F) bounded by the fifth transverse score line  108 , the first and second longitudinal score lines  116 ,  152  and a sixth transverse score line  110 ; and a trapezoidal panel (G) bounded by the sixth transverse score line  110 , the central, lower margin  127 , and beveled left and right sides that joined left and right ends of the sixth transverse score line  110  to left and right ends of the central, lower margin  127 , respectively. The distances between the transverse score lines  100 ,  102 ,  104 ,  106 ,  108 ,  110  should be such that panels (B) and (C) have substantially equal size, but the longitudinal extent of panels (D) and (E) should be somewhat less and that of panel (F) and panel (G) should be still less. 
   The upper left chair side/bottom assembly  114  has a boundary that extends diagonally upward and leftward along a lower left margin  120  from the junction  132  of the second transverse score line  102  with the first longitudinal score line,  116  thence along a first outer left margin  122  that extends diagonally from an outer end of the lower margin  120  upward angled slightly rightward to a point that lies on a line of leftward extension of the first transverse score line  100 . From thence, the boundary extends rightward along an intermediate left margin  124  that is collinear with the first transverse score line  100  part way toward panel (B). From thence the boundary extends diagonally upward and angled slightly rightward along a second outer left margin  126  a distance about equal to the transverse width of panel (B). From thence, the boundary extends rightward along a left top margin  128  to a point that lines on a line of longitudinal extension of the first longitudinal score line  116 , thence downward along the upper left cut line  130 . 
   The upper chair side/bottom assembly  114  is subdivided to include panels (H), (I) (J) and (K). An outer, left, upper triangular panel (H) is bounded by the lower left margin  120 , a first diagonal score line  140  that extends upward and leftward from the junction  132  of the second transverse score line  102  with the first longitudinal score line  116  to the first transverse score line  100 , and a second diagonal score line  142  that extends from thence to the lower left margin  120 . A triangular inner, left, upper panel (I) is bounded by the first diagonal score line  140 , the first longitudinal score line  116 , and a seventh transverse score line  144 . Panel (H) and Panel (I) are each right triangular and share the first diagonal score line  140  as their common hypotenuse. A trapezoidal left seat back tab panel (J) is bounded by the first outer left margin  122 , the intermediate left margin  124 , the second diagonal score line  142 , and the lower left margin  120 . A trapezoidal, intermediate left seat/back panel (K) is bounded by the second outer left margin  126 , the left top margin  128 , the upper left cut line  130 , and the seventh transverse score line  144 . 
   The upper right chair side/bottom assembly  150  has a boundary that extends diagonally upward and rightward along a lower right margin  154  from the junction  136  of the second transverse score line  102  with the second longitudinal score line  152 , thence along a lower a first outer right margin  156  that extends diagonally from an outer end of said lower margin  154  upward angled slightly leftward to a point that lines on a line of rightward extension of the first transverse score line  100 ; thence leftward along an intermediate right margin  158  collinear with the first transverse score line  100  part way toward panel (B), thence diagonally upward and angled slightly leftward along a second outer right margin  160  a distance about equal to the transverse width of panel (B), thence leftward along a left top margin  172  to a point that lies on a line of longitudinal extension of the second longitudinal score line  152 , thence downward along the upper right cut line  162 , said cut line having a lower terminus at the first transverse score line  100 ; thence along the second longitudinal score line  152  to the junction  136  of the second transverse score line  102  with the second longitudinal score line  152 . 
   The upper right chair side/bottom assembly  150  is subdivided to include panels (L), (M), (N) and (O). A triangular outer, right upper panel (L) is bounded by the lower right margin  154 , a fifth diagonal score line  164  that extends upward and rightward from the junction  136  of the second transverse score line  102  with the second longitudinal score line  152  to the first transverse score line  100  at the junction of the intermediate right margin  158  with the second outer right margin  160 , and a sixth diagonal score line  166  that extends from said junction to the lower right margin  154 . A triangular inner, right upper panel (M) is bounded by the fifth diagonal score line  164 , the second longitudinal score line  152 , and an eighth transverse score line  168 . Panel (L) and Panel (M) are each right triangular and share the fifth diagonal score line  164  as their common hypotenuse. A trapezoidal right seat back tab panel (N) is bounded by the first outer right margin  156 , the intermediate right margin  124 , the sixth diagonal score line  166 , and the lower right margin  154 . A trapezoidal, intermediate right seat back panel (O) is bounded by the second outer right margin  160 , the right top margin  172 , the upper right cut line  162 , and the eighth transverse score line  168 . 
   The lower left chair side/bottom assembly  180  is joined to a left end of the panel (C) at the first longitudinal score line  116  from the second transverse score line  102  to the third transverse score line  104 , extends leftward from said panel (C), and includes panels (P) and (Q). The triangular, lower left panel (P) is bounded by the first longitudinal score line  116 , a ninth transverse score line  181  collinear with the third transverse score line  104  and extending leftward therefrom a distance about equal to the length of the left top margin  128 , and a left diagonal margin  182  that extends from the leftmost extremity of the ninth transverse score line to the junction  132  of the second transverse score line  102  with the first longitudinal score line  116 . Trapezoidal, lower left flap panel (Q) has an upper end joined to a lower end of panel (P) at the ninth transverse score line  181 , a left margin  186  that extends from the junction of the ninth transverse score line  181  with the left diagonal margin  182  downward below the level of the fourth transverse score line  106  but well above the level of the fifth transverse score line  108 , a longitudinally-directed lower left cut line  188  that extends about the same length as the left margin  186  below the fourth transverse score line  106 , and a left bottom end that extends leftward from the lowermost point of said cut line  188  to the lowermost point of said left margin  186 . 
   The lower right chair side/bottom assembly  180  is joined to a right end of the panel (C) at the second longitudinal score line  152  from the second transverse score line  102  to the third transverse score line  104 , extends rightward from said panel (C), and includes panels (R) and (S). The triangular, lower right panel (R) is bounded by the second longitudinal score line  152 , a tenth transverse score line  190  collinear with the third transverse score line  104  and extending rightward therefrom a distance about equal to the length of the right top margin  172 , and a right diagonal margin  192  that extends from the rightmost extremity of the tenth transverse score line  190  to the junction  136  of the second transverse score line  102  with the second longitudinal score line  152 . Trapezoidal, lower right flap panel (S) has an upper end joined to a lower end of panel (R) at the tenth transverse score line  190 , a right margin  194  that extends from the junction of the tenth transverse score line  190  with the right diagonal margin  192  downward below the level of the fourth transverse score line  106  but well above the level of the fifth transverse score line  108 , a longitudinally-directed lower right cut line  196  that extends about the same length as the right margin  194  below the fourth transverse score line  106 , and a right bottom end that extends rightward from the lowermost point of said cut line  196  to the lowermost point of said right margin  194 . Panel (P) and panel (R) are right triangular and congruent, and their maximum longitudinal extent equals that of panel (C). Panel (H) is congruent to panel (L) and panel (I) is congruent to panel (M). Likewise, panel (Q) is equal in size to panel (S); panel (J) is equal in size to panel (N); and panel (K) is equal in size to panel (O). As shown by parallel dashed lines in  FIG. 10 , preferably the fifth transverse score line  108 , the first diagonal score line  140  and the fifth diagonal score line  164  are each double score lines, and the fourth transverse score line is a triple score line. 
   The manner of folding the blank  200  is illustrated in  FIGS. 11-20 . Starting with the blank  200  laid completely unfolded and flat, the entire portion of the body that lies below the second transverse score line  102  is folded about said score line  102  so that panel (C) overlies panel (B), panel (P) overlies panel (I), panel (Q) overlies panel (K), panel (R) overlies panel (M), panel (S) overlies panel (O) and panel (D) overlies panel (A); see  FIG. 11 . Next, the portion of the central body  112  that lies below the third score line  104  is folded about said score line  104  so that panel (D) overlies panel (C); see  FIG. 12 . Then, panel (H) is folded about the first diagonal score line  140  so that panel (H) overlies panel (P) and panel (J) partially overlies panel (Q); see  FIG. 13 . Next, panel (L) is folded about the fifth diagonal score line  164  so that panel (L) overlies panel (R) and panel (N) partially overlies panel (S); see  FIG. 14 . Next, panel (P), which lies below panel (H), is folded about the first longitudinal score line  116  to an upstanding position, which thereby also raises panels (I), (J), (K) and (Q) to an upstanding position. Then, panel (R), which lies below panel (L), is similarly folded about the second longitudinal score line  152  to an upstanding position, which thereby also raises panels (M), (N), (O), (R) and (S) to an upstanding position; see  FIG. 15 . Next, panel (J) is folded inward about the second diagonal score line  142  and panel (N) is folded inward about the sixth diagonal score line  166  so that the their respective outer margins  122 ,  170  are in mating engagement above the first transverse score line  100 ; see  FIG. 16 . Then, panel (Q) is folded about the ninth transverse score line  181  behind and adjacent to panels (J) and (N); see  FIGS. 16 and 17 . Next, panel (S) is folded about the tenth transverse score line  190  behind and adjacent panel (Q); see  FIGS. 16 ,  17  and  18 . Then, panel (A) is folded up about the first transverse score line  100  behind and adjacent to panel (S); see  FIG. 18 . Next, panel (K) is folded about the seventh transverse score line ( 144 ) behind and adjacent to panel (A) and panel (O) is folded about the eighth transverse score line ( 168 ) behind and adjacent to panel (K); see  FIGS. 19 and 20 . Next, panel (D) is folded about the third transverse score line ( 104 ) so that panel (D) overlies panel panels (J) and (N), and panel (E) is folded about the fourth transverse score line  106  so that panel (E) is behind and adjacent to panel (O); see  FIG. 20 . Lastly, panels (G) and (F) are tucked between panels (K) and (O), which maneuver is facilitated by the beveled sides of panel (G); see  FIGS. 20 and 21 . This folding sequence converts the blank  200  into a recyclable event chair in an open, sitting position, as depicted in  FIG. 22 . By pivotal rotation of the seat of the chair about the third transverse score line  104  toward the back of the chair, the chair can be collapsed as depicted in  FIG. 23 , wherein the sides of the chair move triangularly outward. Thus, the chair  200  of the second embodiment of the invention is capable of the same bellows-type opening and collapsing motions as that of the first embodiment. 
   From the foregoing description, it will be clear that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It will be understood, for instance, that in the folding of the blank  200  of the second embodiment, the folding of panel (K) behind panel (A) can either precede or follow the folding of panel (O) behind panel (A). As another example, the flange panels (X) and (Y) of the first embodiment of the invention are desirable for user comfort and for durability of the chair, but could be eliminated. As a further example, although certain fold lines in the illustrated embodiments are denoted as double or triple score lines, fewer or additional fold lines may need to be double or triple score lines depending primarily upon the thickness and pliability of the planar material chosen for the blank; accordingly, in the claims, each recitation of the term “score line” is intended to include the possibilities of a single, double or triple score line, whichever may be deemed suitable or necessary by persons of ordinary skill in the relevant arts for the particular thickness and pliability of the planar material chosen for the blank. Thus, the presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and not limited to the foregoing description.