WO1991001665A1

WO1991001665A1 - Unitary chair, formed from fiberboard

Info

Publication number: WO1991001665A1
Application number: PCT/US1989/003379
Authority: WO
Inventors: James Lewis Kelley; James Richard Volpe
Original assignee: James Lewis Kelley; James Richard Volpe
Priority date: 1989-08-04
Filing date: 1989-08-04
Publication date: 1991-02-21

Abstract

The structure is a chair made from one simple blank of two fractional panels (L, S) that join to form one composite rear panel; four other panels (1, 3, 5, 11), and a glue tab (13) with only two glue joints (L to S at 32, and 13 to 3). Its lower parts, a rectangular glued tube, contains a preglued vertical seat-support panel (11, 13, 14), parallel to the side walls (1, 5), that folds and unfolds with the tube. The upper part to the chair is an extension of the tube, but the front panel (24) folds in, back and down to form a seat spanning the tube, held up by the front and seat-support panels. The side panels (1, 5) have scoring (20) to permit buckling, in setting up the chair. The seat-support panel is integrally joined with a smaller one (S) of the two fractional panels; and is also joined directly to the center of the front panel (3) by the glue tab (13).

Description

UNITARY CHAIR, FORMED FROM FIBERBOARD

BACKGROUND

1. FIELD OF THE INVENTION

This invention relates generally to economical, easily transported and rapidly set up chairs suitable for large gatherings such as sporting events, lawn parties or parades; and more particularly to a collapsible, disposable chair of corrugated fiberboard or like generally planar recyclable material.

2. PRIOR ART

The most relevant corrugated-product chair of which we are aware is disclosed in our United States Patent 4,811,987. That patent contains an extensive discussion of prior patents and other art, and their limitations — which discussion is incorporated by reference herein. We have found the chair of that patent to be extremely satisfactory. The present document addresses only certain refinements which we have found desirable under special circumstances or for special applications. The recognition of these special circumstances and special applications is itself a part of the inventive process related to the present invention, and so will be discussed in the following section of this document.

SUMMARY OF THE DISCLOSURE

Our chairs as described in our earlier patent are extraordinarily economical to manufacture, in terms of raw-material requirements. We have learned, however, that in many industrially important parts of the world — in Japan, for example — the price of virgin forest products is extremely high. (Such products, which have longer fibers and therefore greater strength than recycled materials, are favored for making corrugated material suitable for disposable chairs.) In fact the cost of virgin wood products is so high that even the modest material requirements of our chair prove excessive. We have therefore come to the realization that an even more material-conserving chair is very desirable for such parts of the world. The present invention provides such a chair that uses roughly fourteen percent less material than our earlier chair, and is accordingly lighter in weight by the same percentage. Nevertheless, it is actually stronger. We have also found that the relatively fussy or touchy manufacturing-machine setup of our earlier chair somewhat limits the number of available suppliers. Only manufacturing shops capable of performing the setup can do the work; in addition, these more-skilled operations tend to be slightly more expensive. The present invention provides a chair that is much less- fussy or touchy in machine setup than our earlier chair, and accordingly even more amenable to automated manufacture. It thus has a larger population of potential manufacturers and is even more economical to make. We have also noted that some people who are not highly coordinated or who are unaccustomed to learning new manipulatiόhs — such as some elderly people, for example — do have some minor difficulty in setting up our chair. In particular they may be temporarily confused at the need to separately fold down the so-called "stiffening-angle tab" that is described in our earlier patent. The present invention provides a chair that has a stiffening-angle tab, but in this chair that tab automatically folds down when the seat panel is moved into position for use. The tab also automatically folds up when the seat panel is moved back up into position for storage or shipping. Thus the present chair is even more easily set up, or refolded for storage or shipment, than our earlier chair. We have also found that our earlier chairs (or at least some units of the earlier chairs) can be weakened when users lean back in the chair while seated. Although we have never seen any of our earlier chairs collapse as a result of a user leaning back, we have seen the rear panels of some chairs bow outward under these conditions. More specifically, in such outward bowing the rear panel of a chair curves or bends about a generally vertical axis, so that the portions of the rear panel that are partway between the left and right sides protrude rearward well beyond both sides. In some extreme cases, in addition to or as a result of such outward bowing, an irregular crease has formed in the rear panel — generally extending vertically along most of the height of the panel. As we have never seen any of our chairs fail because of these phenomena, even under extremely severe use, we do not consider the bowing or creasing to be hazardous -- only a theoretical or esthetic imperfection. We do, however, consider that eliminating the bowing would be desirable esthetically. Our present invention is far stronger in the front- to-back direction. As a result, we have not seen any of the prototypes of our new chair bow outward significant- ly, or crease at all, due to a user leaning back. Our invention is a very material-saving and strong disposable chair, though it may be reused many times if desired. In only a few seconds — as few as two or three seconds — our invention, if already set up for use as a chair, can be folded flat for storage and shipment; or if in that latter condition can be unfolded and configured for use. The ©hair includes six contiguous panels. For greater clarity in description, however — and particu- larly to aid in comparison with our earlier chair — we shall often refer to these panels as two fractional panels and four other panels. The two fractional panels are fractional with respect to width, and are glued together to form and to function^' as a single composite panel. Thus, within the nomenclature we are using in this document the number of full panels is only five. With this in mind, we shall sometimes refer to all the panels as the "five panels" of the chair. The fractional panels, and the composite panel which they form, are rectangular. The composite panel is the back of the chair; we shall sometimes refer to it as the "first" panel. The invention also includes a substantially rectangular forward panel having portions that respectively form the front and seat of the chair. Also included are two substantially rectangular side panels that respectively form the sides of the chair. Our invention also has a fifth panel. This fifth panel has or defines, among other features, an upper edge. All five of the panels are of material that is of generally planar character — in other words, extended in only two dimensions and substantially very thin in a third dimension. The material is, however, sufficiently stiff and "strong in the aggregate, when configured for use, to support a person. All of the panels define generally vertical edges, at least one such edge per panel. All of the substantially rectangular panels are joined along their vertical edges in a row, and are mutually angled along their vertical edges to form an upstanding generally four-sided tube. A vertical edge of the fifth panel is joined directly to one of the fractional panels at one end of the row, and the fifth panel is disposed erect within the tube. More specifically, the side panels alternate with the fractional panels and forward panel in this order:

(a) one fractional panel that is part of the composite rear panel or first panel,

(b) one side panel or second panel,

(c) the forward panel or third panel,

(d) the other side panel or fourth panel,

(e) the other fractional panel that forms the remainder of said composite rear panel or first panel, and

(f) the fifth panel;

The seat-forming portion of the forward panel is moved downward and inward, with respect to the tube, to be supported by the upper edge of the fifth panel. Each side panel is doubled over and inward, with respect to the tube, along a line extending generally from a top rear corner downward and forward to intersect the forward panel. The foregoing may be a description of our invention in its broadest or most general form. We consider several other features highly desirable, however, and prefer to incorporate them into the structure to enhance the advantageous performance of our invention. One such preferred feature is that the fifth panel is secured to the forward panel too, along a second substantially vertical edge of the fifth panel. Thus the fifth panel preferably spans the chair, but extending between the front and back — rather than, as in our earlier chair, between the two sides. Furthermore we prefer to secure the fifth panel to both the forward panel and the rear panel directly:

- At the forward panel, this direct attachment may be conveniently made by means of a glue tab that is integral with the fifth panel.

- At the composite rear panel, the fifth panel, on one vertical edge, can be integral with an edge of the smaller fractional panel — thus the fifth and rear panels can join not only directly but integrally.

As will be seen by detailed comparison with our earlier chair, this configuration entirely eliminates the so-called "intermediate strip" of our earlier chair. The main function of that "intermediate strip" in our earlier chair is to interconnect one vertical edge of the fifth panel with a vertical edge of one of the other four panels — while spacing the fifth-panel edge away from the mating-panel edge. In our present invention no intermediate strip mutually interconnects, while mutually spacing away, either vertical edge of the fifth panel and any of the other four panels. In our earlier chair, the intermediate strip makes up about 6| percent of the width of the blank. Furthermore, in preferred embodiments of our earlier chair the fifth panel extends across the inside of the chair from side to side. In other words, it is parallel to the front and rear of the chair. Since the earlier chair is nearly fifteen centimeters wider than it is "deep" (referring to the front-to-back dimension) , the fifth panel in our present chair can be nearly fifteen centimeters narrower than that earlier fifth panel. This distance amounts to about ^ percent of the overall width of the blank in our earlier chair. Between these two savings of material — about 6| percent by eliminating the intermediate strip, and about _? percent by using a narrower fifth panel or pillar — our present invention accordingly uses nearly fourteen percent less corrugated product or other sheet material than our earlier chair. This represents a very significant improvement for areas such as Japan in which raw materials and particularly wood-based products are extremely costly. Another feature that we prefer, to enhance user comfort and maximize the stability of the chair, is to configure the chair so that the fifth panel is secured directly at about the center of the composite rear panel. To achieve this condition we prefer to make the "other" fractional panel (d) — the one that is joined between the fourth and fifth panels — in the form of a relatively smaller fractional panel. We further prefer to make the "one" fractional panel (a) — the one that is joined to the second panel — in the form of a relatively larger fractional panel that extends slightly behind and is secured to part of the back of the smaller fractional panel . Another preferred feature is a short upward extension of the fifth panel, folded over at a right angle just at the junction with the fifth panel. This extension, by virtue of the angle at the fold, greatly stiffens the upper edge of the fifth panel against collapse when a user's weight is placed on the seat and on that upper edge. Accordingly we shall refer to the short extension as a "stiffening-angle tab." It is joined to the fifth panel along the upper edge of that panel, and folded downward and toward one side -- toward an orientation that is at least roughly parallel with an underside of the seat. Preferably the fifth panel and the stiffening-angle tab are unitary and are mutually demarcated by, in part, a transverse score along which they are mutually folded and by, in part, a generally transverse through-cut. Preferably the through-cut interrupts the score in a certain region, and is at least in part offset from a projection of the score through that region. The offset through-cut causes part of the fifth panel — the part below the projection of the score through the "region" — to function as a part of the stiffening-angle tab. This part of the fifth panel accordingly is caused to be folded toward an orientation generally parallel with the underside of the seat, together with the stiffening-angle tab generally. Moreover the part of the fifth panel below the projection of the score through said region, upon being folded toward an orientation generally parallel with the underside of the seat, leaves a declivity in the upper edge of the fifth panel. This declivity which is thus created — and also the stiffening-angle tab, and the part of the fifth panel that is oriented generally parallel with the underside of the seat — cooperate to enhance the comfort of a person using the chair. The through-cut converts a shallow part of the fifth panel from being part of the vertical-support column to being a part of the horizontal tab. The result is to moderate the stiffening action of the tab, and at the same time to create the above-mentioned declivity or shallow depression — in effect a cavity below the horizontal tab — in the upper end of the vertical column. These two effects in turn permit a slight sagging of the seat panel into the cavity in the top of the vertical part of the reinforcement panel. This slight controlled deformation conforms to a user's body, to greatly enhance the user's comfort — particularly in protracted use. At the same time a useful fraction of the stiffening action of the tab is retained, so that the structural advantages¹ of the fifth panel and its stiffening tab are maintained. By extensive trial and error we have learned how to dimension the offset cut to optimize the tradeoff between stabilization of the structure and enhancement of the user's comfort, and we do not in the slightest sacrifice the economy, ease of manufacture, compactness, or any other beneficial property of our invention. Still another preferred feature is an actuator panel, joined along a diagonal folding score to the stiffening-angle tab. The actuator panel is also joined along a forward edge to the forward panel, along a portion of the forward panel that forms the seat of the chair. When the seat is moved downward and inward to be supported by the upper edge of the fifth panel, the underside of the seat folds the actuator panel downward — and the actuator panel in turn automatically folds the stiffening-angle tab downward. Accordingly the person setting up our present invention for use, or refolding it for storage or shipment, need not manipulate the stiffening-angle tab separately. The fifth panel in our present chair is very roughly the same height as that in our earlier chair. As will be seen, however, in our present chair the stiffening-angle tab and actuator panel are taller than the stiffening- angle tab in our earlier chair — so that when combined with the fifth panel they use a much larger fraction of the full blank height than did the stiffening-angle tab in our earlier chair. In fact, combined with the fifth panel they use almost the full height of the blank. In our earlier chairs, however, the portion of the blank above the stiffening-angle tab is waste material. Therefore the present stiffening-angle tab and actuator panel, although of greater height, actually use no more raw material. We also prefer to make our present invention with the upper edge of the fifth panel angled slightly off the horizontal — more specifically, inclined from the rear of the chair toward the front. Similarly, the seat-forming portion of the panel that forms the front and seat of the chair, upon being moved downward and inward to be supported by the upper edge of the fifth panel, is (at least near its center) also inclined slightly from the rear of the chair toward the front. The same is true of the stiffening-angle tab, after being folded downward and toward one side. A user's comfort is enhanced by the slight inclination of the seat and of those internal support components. In another preferred feature, the seat panel is scored — or otherwise adapted for folding — along additional intermediate angled lines. These additional fold lines permit a controlled deformation of the seat for dded comfort of the user. All of the five panels, and the intermediate strip and the vertical tab as well, can be formed of a single novel unitary blank, with the panels and related elements in the order (a) through (f) presented above. Our invention, as defined by the appended claims, also encompasses the novel blank for making the chair. We prefer to make the composite rear panel and the front panel of mutually equal width, and the two side panels and fifth panel all of mutually equal width, so that the tube is rectangular in plan and the internal fifth panel folds and unfolds in parallelogram fashion with the outer panels. Our invention also encompasses methods for using the chair, e. g. a method of preparing for reuse or disposal:

(1) providing the chair configured for use in supporting a person on the seat-forming portion;

(2) after such use is completed and a person no longer occupies the chair, grasping the seat-forming portion and lifting it away from the back of the chair — and thereby also automatically moving the actuator panel attached to the stiffening-angle tab, and the stiffening-angle tab itself;

(3) continuing the motion of the seat-forming portion (and the stiffening-angle tab) upward and forward until the seat is generally vertical; (4) then folding the tube from its rectangular plan condition to its generally flat condition; and

(5) then shipping the folded chair as a flat tube to a subsequent point of use or storage.

Another method within the scope of our invention is the converse method for placing the chair in use. It includes these steps:

(1) shipping the folded and secured blank as a flat tube to a point of use;

(2) then unfolding the tube to its rectangular plan condition;

(3) then pushing the seat-forming portion backward, inward relative to the tube, and downward against the back — and simultaneously, through operation of the actuator tab, automatically pushing the stiffening-angle tab toward one side, and downward -- all to be supported by the upper edge of the .fifth panel; and

(4) then providing the chair for use in supporting a person on the seat-forming portion.

As will now be clear, our invention provides a very light but strong, reinforced disposable (or reusable) chair that may be made of corrugated fiberboard very inexpensively, with negligible waste. It requires extremely little preliminary assembly -- and even that can all be performed by very simple machine operations. The chair takes a very minimum of space for shipment and storage, and only a very few seconds of unskilled labor for setup or knockdown. This chair has not even one assembly tab to slow either task -- or to wear or be damaged — and its stiffening-angle tab folds both down and up automatically. It is greatly improved over our earlier chair in that it is much stronger and much more economical of raw material — and therefore much less costly in areas where the preferred virgin forest-industry products are very expensive. It is also open to manufacture by a greater number of potential suppliers, including some who might have difficulty with the touchy machine setup of our earlier chair — and whose services tend to be somewhat less expensive. Accordingly the economy of this chair is improved in at least two different ways. The principles and advantages of our invention will be more fully appreciated upon consideration of the following details, with reference to the appended drawings, of which:

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an isometric drawing of a preferred embodiment of our invention, shown configured for use in supporting a person. Fig. 2 is a front elevation of the same embodiment. Fig. 3 is a side elevation, in section, of the same embodiment — taken along the plane 2-2, indicated in Fig. 2, which passes through the overlap region of the two fractional panels at the rear of the chair. Fig. 4 is an isometric or perspective drawing of the same embodiment folded flat for storage or shipment (or disposal), but stood up on edge as if just removed from a pallet. Fig. 5^' is a like view, but taken from below (with respect to the chair). It shows the same embodiment, still standing on edge, but now in the process of being opened from the Fig. 4 condition into a vertical rectangular-tube condition for use. Fig. 6 is a like drawing, also taken from below and showing the same embodiment at an intermediate stage of assembly — namely, folded open to a rectangular tube, with the seat panel not yet in position for use. Fig. 7 is a like drawing, but taken from above, showing the same embodiment at generally the same stage but now standing erect. Fig. 8, a like drawing, shows the same embodiment at the next intermediate stage of assembly, with the rectangular tube still vertical and the seat now started inward. Fig. 9 is a like view, showing the same embodiment at the next stage, with the seat folded fully down into position for sitting as in Fig. 1, but showing the various panels as if transparent. Fig. 10 is a bottom plan view of the same embodiment assembled, showing the various internal components in their interrelationships that result from moving the seat into position. Fig. 11 is an orthographic drawing of the single unitary blank (in its initial flat condition) from which the same embodiment is assembled.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in Figs. 1 through 3, and also in Figs. 9 and 10, a preferred form of our invention when set up for use is a chair with a rectangular seat panel 24 (including three subpanels or portions 24' and 24F) . The seat panel 24 is slightly inclined from the horizontal, and when receiving the weight of a user is usually also bent slightly at two scores 24S (Fig. 9) to form two laterally angled facets 24F. In this configuration, high pressure applied by the user's weight to the center of the seat 24 is slightly relieved and redistributed to the side facets 24F. (For people in an average range of sizes, if these facets were not angled the user's weight would not be directly applied to the facet areas.) The result is primarily added comfort of the user and secondarily some slightly enhanced redistribution of the user's weight through the facets 24F to the side panels 1, 5. The same chair also has generally vertical rectangular front and rear panels 3 and R (Fig. 1) respectively.⁴ The rear panel R in turn is made up of two fractional panels — one smaller S and one larger L. In the embodiment shown, the smaller fractional panel S is at the left, the larger one L at the right. (All references to lateral direction in this description are as viewed from in front of the chair. ) Of course the chair can be made in a mirror-image configuration with the sides reversed. Each of the fractional panels S, L is subdivided by scores 16S, 16L, 18S, 18L that function when a user is seated in the chair to relieve pressure at particular areas, redistributing the resulting force to other parts of the chair. The rear-panel scores include horizontal scores 16S, 16L extending horizontally across the smaller and larger panels S, L respectively, just above the seat panel. Also- included are diagonal scores 18S, 18L each of which starts from the outer edge of its respective panel, at a point just above the respective horizontal score 16S, 16L; and extends upward at an angle toward a point that is along he top edge of the same panel and roughly one-third of the distance across the entire composite rear panel R. These scores divide each panel S, L into three portions — trapezoidal central upper subpanels 25S, 25L, triangular upper-corner subpanels 31S, 31L, and bottom subpanels 7S, SL. The bottom subpanel 7L of the larger fractional panel L is rectangular; however, the other bottom subpanel 78S has one corner 51, 52 that is notched or cut away. When a user leans back in the chair, all of the upper subpanels tilt rearward somewhat to accommodate the movement. In tilting the central subpanels 25S, 25L tend to rotate about the horizontal scores 16S, 16L as an axis of rotation; and the corner subpanels 31S, 31L tend to angle rearward toward the central subpanels 25S, 25L. These descriptions are necessarily very simplified, because all the panels typically curve and bend out of planarity, particularly for larger and heavier users. The two fractional panels S, L overlap each other along a step-shaped narrow vertical area or strip 32, which extends the full height of the chair. This overlap strip 32 is used for securing the panels S, L together — preferably by glue — to form the composite panel R. The notch or step 51-52 (Fig. 10) in the smaller panel S — specifically, in the overlap/glue strip 32 — moves the top part of the composite-panel joint (the part that is above the seat) off-center to the left, where it is less disturbing to a person leaning back in the chair and where it does not interfere with the handhole 17. The step 51, 52 does, however, carry the bottom part of the joint onward, by the additional width of the step 52, to the chair center. Thus the pillar 14 is on-center. The chair also has generally vertical left and right side.panels 1 and 5 respectively. The portions of these two panels seen in the assembled chair appear trapezoidal, but in the blank from which the chair is made these side panels are very nearly rectangular. More specifically, the upper portions of the sides of the chair (the portions above the seat 24) are double walled, with inner side panels 30 on the right side and 27 on the left. These inner side panels 30 and 27 are continuous with the outer side panels 5 and 1 respectively, being folded over at double folds 19, and they suspend the seat 24. These panels 1-27, 3-24, 5-30 and R are the four rectangular panels mentioned above in the "Summary". As shown in Fig. 3 and Figs. 6 through 10, the seat also rests upon an internal cross-panel 11 (the "fifth panel" mentioned earlier), which is stabilized by a right-angle fold 15 at the base of part of its extension panel or stiffening-angle tab 14. Thus the seat is triply supported — in compression by the front panel 3 and internal panel 11, and in tension by the inner side panels 27, 30. ^"The internal cross-panel 11 typically bears the major part of the weight of a person occupying the seat. The front panel 3 typically bears the next largest fraction σf-the weight. The tension effect of the inner side panels 27, 30 in suspending the seat 24 normally comes into play only if the occapant enters the seat in such a way as to slightly damage the internal cross-panel 11 or to slightly disrupt the stiffening effect provided by the right-angle fold 15 — or if the occupant sits in the seat in a skewed fashion that tends to slightly lift the seat away from the internal cross-panel 11. Support by -^*the side panels 27, 30 is, however, somewhat greater when the user's weight brings the seat facets 24F into operation as described earlier. The preferred form of our invention can also assume the flattened or "closed" configuration of Fig. 4. In this- condition it is extremely compact. More specifically, the overall thickness is only at maximum three layers of the fiberboard or other material, while the overall "height" (that is, the lengths of the glued areas 32) is only equal to the height of the back panel of the erect chair. Furthermore, the width of the flattened chair is the sum of the widths of only two panels — e. g.. front panel 3 and side panel 1, as shown. In the rear panel R, when the chair is folded flat for shipment, storage or disposal, the upper portions 25S, 25L, 31S, 31L are generally roughly coplanar with the respective lower portions 7S, 7L. The handhole 17, formed through the larger fractional panel L, is for convenience in carrying. In Fig. 4 the chair, though still in its "closed" configuration, is on edge — as if, for example, it has just been removed from a horizontal disposition on a shipping pallet, and rotated ninety degrees onto one edge. Figs. 5 and 6 represent two configurations of the chair. These configurations are intermediate between the flattened or "closed" condition of Fig. 4 and the opened condition of Figs. 1 through 3. In the first intermediate configuration of Fig. 5, the flattened or "closed" chair of Fig. 4 is still erect, but now partially unfolded, or "folded open," into a parallelogram-shaped tube. To obtain this condition from that of Fig. 4, a person first opens the tube from its completely flattened or "closed" condition, so that the bottom two panels 5 and 7S-7L are no longer coplanar — and similarly with the top two panels. After the chair has once been set up and refolded, the natural springiness of the 180-degree folds 4 and 33 will very slightly open the tube without the user's assistance. In that case, this "first step" takes virtually no time at all, and occurs without effort on the part of the person assembling the chair — as soon as the chair is placed on edge or even earlier. Next one moves the fold score 4 that is at the right edge of the flattened or "closed" chair (as viewed in Figs. 4 and 5) toward the left relative to the fold score 33 that is at the left edge. The latter part of this motion is indicated by the arrows 41 and 42 appearing in Fig. 5. As can be seen in Fig. 5, the internal "fifth panel" 11 (with its extension panel 14, not visible in Fig. 5) is parallel to the front and back panels 3-24 and R. Thus the fifth panel 11, 14 folds open as a parallelogram along with the front and back panels 3-24 and R. Fig. 5 also illustrates attachment of this panel 11 to the forward panel 3 by a glue tab 13; and to the smaller fractional panel S because it is integral with that panel along the folding score 10. By continuing to unfold the parallelogram-shaped tube until the angles between adjacent panels (e. g.. at the principal fold lines 2, 4, 6 and 33) are all substantially right angles, one eventually brings the chair to the substantially rectangular-tube condition shown in Fig. 6. The chair in this condition is now rotated to stand erect on its bottom end, as shown in Fig. 7. Next, as shown in Fig. 8 the top edge of the seat panel 24 is pushed inward. If the inner side panels 26-27 and 29-30 (and the seat panel 24) were rigidly planar, it would not be physically possible to move the seat panel 24 from its Fig. 7 position to its Fig. 9 position. This is so even though the side panels are generally planar after the chair has been erected. The reason is that the left and right edges of the seat panel must pass directly adjacent to the upper diagonal double fold lines 19; but, if the inner side panels 30, 27 were rigid and planar, they would force the seat panel 24 away from the fold lines 19 in the intermediate portions of the motion. To permit lowering of the seat, the upper inside panels are divided into portions 26 and 27 on the left, and 29 and 30 on the right. These are separated by respective auxiliary or intermediate fold lines 20, which allow the upper portions 26 and 30 to angle relative to their respective lower portions 27 and 29 -- so that the fold lines 20 buckle outward as indicated in Fig. 7 — thus passing through a "lost motion" phase. Thus as shown in Fig. 8 the entire seat panel 24 is pushed backward, inward and downward to the position represented in Fig. 9. In this process the side panels 26-27 and 29-30 are reflattened at their diagonal scores 20; and the original outer-corner scores 2 and 4 (above the seat-forming score 22) are reversed, becoming inner corners, and are tucked into position against the inner side walls of the chair. In addition, as previously mentioned, the seat panel can be deformed along its diagonal scores 24S so that the side facets 24F are angled out of planarity with the central seat panel 24'. Since the seat panel 24 spans the front-to-back depth of the chair, if it were horizontal its length would substantially equal the common widths of the side panels 1 and 5; and the angle of the double-fold lines 19 to the horizontal would be forty-five degrees. That is not precisely so in the preferred embodiment here shown and discussed, since the seat panel 24 is not horizontal. In fact the seat panel is very slightly longer than the common widths of the side panels 1 and 5, and the angle of the double-fold lines 19 accordingly is slightly steeper than forty-five degrees. Moreover the upper edges of the full side panels in the blank are slightly angled relative to all the other top and bottom edges of the "substantially rectangular" panels (see in Fig. 11), so that the side panels are not rectangular precisely. To the extent that the seat panel is generally horizontal, however, the height of the seat panel above any support surface roughly equals the difference between the overall height of the chair and the front-to-back depth of the chair — which is to say, the vertical length of the seat panel 24 before it is pushed back. The entire assembly process reduces to just three simple motions: standing the tube on end, opening it to rectangular form, and pushing the seat into place. There is no slot-and-tab fitting step. Accordingly, unskilled personnel can perform this entire final-assembly or erecting procedure in just three seconds, or perhaps as much as five seconds. Moreover they can do so after only a few minutes' training -- which generally consists of seeing the procedure once. Such personnel can even more rapidly refold the chair for shipment, storage and/or disposal by simply reversing the procedure just described. That is, the seat 24 and extension 14 are first folded forward and upward, and the seat 24 outward, to regain the Fig. 6 rectangular-tube structure. The hand-access slot 21 in the seat 24 facilitates this process. This slot makes it unnecessary to reach through the chair from the bottom to start the seat 24 and extension panel 14 upward from their horizontal positions of Figs. 1 through 3 and Fig. 9. The rectangular structure is then simply allowed to collapse. It passes through the parallelogram condition of Fig. 5 to the flattened condition of Fig. 4. In both unfolding and refolding, the motions of the seat 24 are automatically transmitted by the actuator panel 14A to the extension panel 14, making the entire process even easier. The Fig. 4 starting point of the final-assembly process shown in Figs. 4 through 7 is a structure that has already been preliminarily assembled. The preliminary steps include partial folding, securing of the two fractional panels L and S to each other along their overlap strip 32, and securing of the tabs 13 and 13A to the inside of the seat panel 24. ' We prefer to perform such securing by the use of glue, and preferably by automatic machinery which can fold and glue the blank to obtain the flattened form of Fig. 4. The securing may instead, however, be accomplished with heat-sensitive or chemically sensitive construction materials, staples, etc. Figs. 7 through 9 show how our entire chair can be folded up from a single blank of sheet material. They thus implicitly show also how the flattened form of Fig. 4 of our invention can be prepared from such a blank. The relationship between Figs. 11 and 7 may be conceptualized as follows. In essence, the front panel 3 remains in position while the other panels are folded "rearward" or "downward" out of the plane of Fig. 11, and then transversely below the plane of Fig. 11 toward one another to obtain the enclosed form or rectangular tube of Fig. 7. The two fractional panels L, S are glued together along their overlap strip 32. The "fifth panel" 11 with its extension 14, and the glue tab (or more generally "securing tab") 13 are all folded forward in a right angle at the rear-center vertical fold line 10. As a consequence the "fifth panel" 11 and extension 14 are inside the tube, and are parallel to and midway between the side panels 1, 5. The glue tab 13 is folded in another right angle — either in the same or preferably (as illustrated) the opposite sense — at its vertical fold line 12. Hence the glue tab 13 is parallel to the front panel 3. A secondary glue tab 13A, integral with the actuator panel 14A, is secured to the underside or inside of the seat panel 24, generally along its centerline. The actuator panel 14A in turn is integral with the extension panel or stiffening-angle tab 14. Now we will describe in more practical terms the assembly procedures leading to the flattened configuration of Fig. 4. The sheet stock should first be printed by a silkscreen or direct-printing process, and then die-cut, scored and perforated from the "inside." After that, glue is applied to the tabs 13, 13A on the inside of the sheet. Then the blank is folded over along the rear edge 33 of the left side panel 1 to glue the tabs 13, 13A to the inside of the front-and-seat panel 3-24. Next, glue is applied to the overlap area 32 on one fractional panel — preferably the larger fractional panel L — in a step-shaped stripe along the inside surface of its extreme edge 8 (which after assembly will be positioned partway across the composite rear panel R). Finally, the blank is folded along the corner 4 between the right-side panel 5 and the front-and-seat panel 3-24, to secure the larger fractional panel L to the outside of the smaller fractional panel S. In this last step of machine assembly, the outside edge 8 of the larger fractional panel L simply overlaps the folded edge 10 of the smaller panel S, by a distance of roughly 5 or 6 centimeters near the top of the blank, and about twice that distance near the bottom. The precise overlap distance is not critical; and more importantly the outside edge 8 of the larger panel L only extends partway (just over halfway) across the structure as folded at that stage. By comparison, in the final machine-assembly step in our earlier chair the last panel folded down for gluing extends all the way to the edge formed by the previous fold at the far end of the folded structure. The machine setup required to produce this configuration is rather touchy or fussy. This difference is what makes the present invention less fussy in machine setup, and therefore more readily manufactured (as mentioned earlier) by shops that are not oriented toward jobs with touchy setup. We prefer to have the blank shown in Fig. 11 made from double-wall corrugated fiberboard with a Mullen test of 19.3 to 24.6 kg/cm² (275 to 350 pounds per square inch) bursting strength or liner-weight combination of 538 to 616 g/m² (110 to 126 pounds per thousand square feet) . We also prefer B-type medium fluting toward the outside of the glued tube, and C-type fluting inside. With allowance for material thickness and fold widths, dimensions can be scaled up or down for the sizes of people to be accommodated. In mass production for use by the general population in the United States we prefer:

- overall height of the blank (that is to say, length of edge 8, and of fold scores 2, 4, 6 and 33), 71.1 centimeters^"; - width of the chair (i. e. , the fold-centerline-to-fold- centerline length of fold line 22), 43.2 centimeters; - front-to-back depth of the chair (that is, the fold- centerline-to-fold-centerline width of panels 1 and 5), 28.4 centimeters; - height of the front edge of the seat above a support surface (that is, the fold-centerline-to-cut-edge length of that portion of the fold lines 2 and 4 that is below the fold line 22; or the height of the bottom portion 3 of the front panel) about 43 centimeters; and - width of the glue tabs 13, 13A (cut-edge-to-fold- centerline), 4.6 centimeters, but dependent upon the type of glue or other securing means employed.

For user comfort we prefer to shape and dimension the fractional panels L, S so that the "fifth panel" 11 is substantially at the chair centerline. However, the important economy, strength, and automatic-tab-deployment advantages of the present invention can be obtained in a chair whose fifth panel 11 is off-center. Furthermore the economy advantages can be enjoyed and even enhanced in a chair whose fifth panel 11 is not secured to the front panel 3 — or does not even extend all the way forward to that front panel 3, but rather is simply free-standing within the tube, generally in position to support the seat. This latter variant will not be as strong, and requires separate manual deployment of the stiffening-angle tab (if present). ' We have recently refined the stiffening-angle tab to optimize a tradeoff between structural stabilization and user comfort. Part of our invention lies in our recognizing that in this type of chair too much stability degrades the comfort of users — especially in protracted use. These refinements are particularly important in the present invention, because it provides a chair that intrinsically is extremely rigid. We have developed a structural feature that moderates the stiffening action provided by the stiffening-angle tab. The amount of this moderation can be quantitatively controlled by selection of the precise dimensions of this feature, so that by trial and error it is possible to optimize the comfort of a user of specified dimensions and weight. This optimization can simply be performed for a typical adult user. If preferred, a corresponding variety of optimal dimensions can be worked out for users of a variety of heights and weights. Blanks for making our chairs with a variety of dimensions can be prepared for use by different groups of people, when it is feasible to determine in advance the sizes and weights of people who will be using the chairs. These refinements include:

(1) providing a through-cut 15c that is shaped to have a relatively long segment 15o which is offset from the geometric.extension of the fold line 15; and

(2) angling the upper edge of the fifth panel slightly off the horizontal, so that the support surface of the seat conforms to the contours of a user's body — and particularly to the natural orientations of a user's frame (notably the upper legs) when seated.

The through-cut 15c advantageously can be formed with two short end segments 15e, relatively sharply angled to the fold line 15, that substantially connect the through-cut 15c to the fold line 15. The through-cut 15c if preferred can be instead tapered back to the fold line 15. The configuration of the cut which we prefer is a hybrid of these two possibilities — a five-segment path. A central segment 15o parallels the fold line 15, two very short end segments 15e are perpendicular to the fold line 15, and two intermediate very shallowly tapered segments 15t connect the short end segments 15e with the central segment 15o. It is not absolutely necessary that the connection of the through-cut 15c to the fold 15 be completed by die-cutting; reliance can instead be placed on a very slight amount of tearing or buckling to complete this connection. We prefer, however, to control the manner and location of this connection by die-cutting the through-cut back to the fold line. As can be seen from the drawings, when the seat is folded for use the offset through-cut creates a short sideward horizontal extension 15f of the horizontal panel 14, and a shallow declivity or cavity 15d in the top of the associated vertical panel 11. The user's weight is supported in part on the combined horizontal surface 15f-14 of the fifth panel. This combined horizontal surface spans the declivity or cavity 15d. In use the user's weight deforms the seat panel 24 and the combined horizontal surface 15f-14. In this deformation the user's weight presses the combined horizontal surface 15f-14 partly or completely (depending upon the user's weight and dimensions) downward into the declivity 15d. For a user of medium or greater size and weight, the chair by this deformation tends to conform to the user's shape. For a smaller and lighter user, the combined horizontal surface tends not to "bottom out" in the declivity 15d and thus instead retains some springiness. This configuration thus promotes comfort for both users. The previously mentioned five-segment cut configuration causes the declivity in the vertical portion 11 of the fifth panel to be gently tapered for comfortable conformance to the body of a middle-size, middle-weight user, but still provides a small vertical drop at each end of the declivity to create a springy "span" effect for smaller, lighter users. (Our invention does not depend on the accuracy of these analyses or theories. ) For adults in a normal range of size and weight, we prefer to make the length of the offset cut 15c approximately 23 centimeters, and the maximum offset roughly 1.8 centimeters. The finger notch 21 in the back panel can be approximately 4.4 centimeters wide, and approximately 1.9 centimeters deep, It is possible to adjust the offset-cut parameters for users' size and weight. Both the length of the offset cut 15c and the maximum offset distance (the distance from the offset segment 15o of the cut and the extension of the fold line 15) may be progressively decreased for relatively larger, heavier people. Such users seem to slightly deform the structure for themselves, without the need for a built-in stiffening- moderation (or "weakening") feature. For such people it is accordingly preferable to trade away some comfort and gain greater stability. The foregoing disclosure is intended to be merely exemplary, not to limit the scope of the invention — which is to be determined by reference to the appended claims.

Claims

WE CLAIM :

1 1. A very material-saving and strong disposable

2 chair that in a few seconds can be folded

3 substantially flat for storage and shipment or

4 unfolded and configured for use; said chair

5 comprising:

6 two substantially rectangular fractional panels,

7 which together form a composite first panel that is

8 also substantially rectangular and is the back of the

9 chair;

10 a substantially rectangular forward panel having

11 portions that respectively form the front and seat of

12 the chair;

13 two substantially rectangular side panels that

14 respectively form the sides of the chair; and

15 a fifth panel that defines an upper edge;

16 all of the panels being of material that is of

17 generally planar character, extended in only two

18 dimensions and substantially very thin in a third

19 dimension but sufficiently stiff and strong in the

20 aggregate, when configured for use, to support a

21 person; and all of the panels defining generally

22 vertical edges, at least one such edge per panel;

23 all of said substantially rectangular panels

24 being joined along their vertical edges in a row, and

25 being mutually angled along said vertical edges to

26 form an upstanding generally four-sided tube;

27 a vertical edge of the fifth panel being

28 joined directly to one of the fractional panels at

29 one end of the row, and the fifth panel being

30 disposed erect within the tube;

31 the side panels alternating with the fractional

32 panels and forward panel in this order: 33

[Claim 1 concludes . . . ] [Claim 1 concluded:]

35 (a) -^* one fractional panel that is part of the

36 composite rear panel or first panel, 37

38 (b) one side panel or second panel,

39

40 (c) the forward panel or third panel,

41

42 (d) the other side panel or fourth panel,

43

44 (e) the other fractional panel that forms the

45 remainder of said composite rear panel or

46 first panel, and 47

48 (f) the fifth panel; 49

50 the seat-forming portion of the forward panel

51 being moved downward and inward, with respect to the

52 tube, to be supported by the upper edge of the fifth

53 panel; and

54 each side panel being doubled over and inward,

55 with respect to the tube, along a line extending

56 generally from a top rear corner downward and forward

57 to intersect the forward panel.

1 2. The chair of claim 1, wherein:

2 the fifth panel defines a second substantially

3 vertical edge that is secured directly, as by an

4 integral glue tab, to the forward panel; and

5 no intermediate strip mutually interconnects,

6 while mutually spacing away, either vertical edge of

7 the fifth panel and any of the other four panels. 3. The chair of claim 1, wherein: said other fractional panel (d), joined between the fourth and fifth panels, is a smaller fractional panel; and said one fractional panel (a), joined to said one side panel or second panel, is a larger fractional panel that extends slightly behind and is secured to part of the back of the smaller fractional panel.

4. The chair of claim 1, further comprising: a stiffening-angle tab joined to the fifth panel along the upper edge.of that panel, and folded downward and toward one side, toward an orientation that is at least roughly parallel with an underside of the seat.

5. The chair of claim 4, wherein: the fifth panel and the stiffening-angle tab are unitary and are mutually demarcated by, in part, a transverse score along which they are mutually folded and by, in part, a generally transverse through-cut; the through-cut interrupts the score in a region, and is at least in part offset from a projection of the score through that region; the offset through-cut causes part of the fifth panel below the projection of the score through said region to function as a part of the stiffening-angle tab and to be folded toward an orientation generally parallel with the underside of the seat, together with the stiffening-angle tab generally.

6. The chair of claim 5, wherein: said part of the fifth panel below the projection of the score through said region, upon being folded toward an orientation generally parallel with the underside of the seat, leaves a declivity in said upper edge of the fifth panel; and said declivity, and the stiffening-angle tab and said part of the fifth panel oriented generally parallel with the underside of the seat, cooperate to enhance such person's comfort.

7. The chair of claim 4, further comprising: an actuator panel, joined along a diagonal folding score to the stiffening-angle tab; and joined along a forward edge to the forward panel, along a -portion of the forward panel that forms the seat of the chair; wherein the underside of the seat folds the actuator panel downward, and the actuator panel in turn folds the stiffening-angle tab downward, when the seat is moved downward and inward to be supported by the upper edge of the fifth panel.

8. The chair of claim 1, wherein: said upper edge of the fifth panel is inclined slightly from the rear of the chair toward the front; and the seat-forming portion of the panel that forms the front and seat of the chair, upon being moved downward and inward to be supported by the upper edge of the fifth panel, is at least near its center also inclined slightly from the rear of the chair toward the front.

9. The chair of claim 4, wherein: said upper edge of the fifth panel is inclined slightly from the rear of the chair toward the front; the seat-forming portion of the panel that forms the front and seat of the chair, upon being moved downward and inward to be supported by the upper edge of the fifth panel, is at least near its center also inclined slightly from the rear of the chair toward the front; the stiffening-angle tab, after being folded downward and toward one side, is also inclined slightly from the rear of the chair toward the front; and a user's comfort is enhanced by the slight inclination of the seat.

10. The chair of claim 2, wherein: said generally vertical edges, at least one such edge per panel, of said substantially rectangular panels are all of substantially equal length, which length is substantially the overall height of the chair; said joined and mutually angled substantially rectangular panels are joined along their substantially equal-length edges and mutually angled along their substantially equal-length edges; the composite panel and said forward panel being mutually of substantially equal width, which is substantially the width of the chair when in use; said two side panels being mutually of substantially equal width, which is substantially the front-to-back depth of the chair when in use; and the tube is of substantially rectangular plan.

11. The chair of claim 10, wherein the fifth panel: is parallel and nearly equal in width to the left and right side panels.

12. The chair of claim 11, wherein: said one side panel or second panel is a right side panel, and said other side panel or fourth panel is a left side panel.

13. The chair of claim 12, wherein: in use said seat-forming portion contacts the back of the chair.

14. The" chair of claim 13: further comprising a generally vertical tab, unitary with said other of the two vertical edges of the fifth panel, that secures said other vertical edge to the forward panel; all of said panels, and the vertical tab, being formed of a single unitary blank having two ends, the panels being provided by said blank in said row from one end of the blank to nearly the other end of the blank, in the order (a) through (f) as above recited, and the tab being at the other end of the blank.