PCT ORLD. INTELLECTUAL PROPERTY ORGANIZATION

International Bureau

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(51) International Patent Classification 3; (11) International Publication Number: WO 80/02790

Al A47C 3/04 (43) Interna-iona_Pub_icationDate:24 December 1980(24.12.80)

(21) International Application Number: PCT/US 80/00702 (81) Designated States: AT (European patent), AU, BR, CH (European patent), DE (European patent), DK, FR

(22) International Filing Date: 4 June 1980 (04.06.80) (European patent), GB (European patent), JP, NL (European patent), SE (European patent).

(31) Priority Application Numben 046,836

Published

(32) Priority Date: 8 June 1979 (08.06.79) With international search report Before the expiration of the time limit for amen¬

(33) Priority Country: US ding the claims and to be republished in the event of the receipt of amendments.

(71) Applicant; and

(72) Inventor: ROWLAND, David, Lincoln [US/US]; 8 East

62nd Street, New York, NY 10021 (US).

(74) Agent: WICKERSHAM,Robert,E.; Owen, Wickersham & Erickson, 433 California Street, 11th Floor, San Francisco, CA 94104 (US).

(54) Title: STACKABLE CHAIR

(57) Abstract

A stacking chair and a metal chair frame there¬ for. One frame member (60) has an U-shaped, horizon¬ tal portion and a pair of vertical front legs. The horizon¬ tal portion comprises a lateral rear portion (65) and hori¬ zontal side portions (66, 67) that lie generally parallel to each other, but diverge somewhat from rear to front. Each of two flanged frame juncture members (63, 64) has a horizontal top and a pair of vertical side flanges; the top has a pair of horizontal edges and each side has a pair of vertical edges. One horizontal edge and two vertical edges of each are welded to the frame side potrions adja¬ cent the rear lateral portion. Rear legs (61, 62) with inte¬ gral back-support portions are welded to the other hori¬ zontal and vertical edges, so that they are spaced apart from each other farther than are the front legs. The rear legs may be two separate members or there may be a single continuous member (121) including both legs and joined at the top. A seat (52) (preferably non-rigid, resilient) bridges and is secured to the frame side por¬ tions and urges them toward a truly parallel relationship, and a similar back (53) bridges and is secured to the back-support portions and, if they diverge, urges them toward a truly parallel relationship.

FOR THE PURPOSES OF INFORMATION ONLY

Codes used to identify States party to the PCT on the front pages of pamphlets publishing international appli- cations under the PCT.

LI Liechtenstein

AT Austria LU Luxembourg

AU Australia MC Monaco

B Brazil MG Madagascar

CF Central African Republic MW Malawi

CG Congo NL Netherlands

CH Switzerland NO Norway

CM Cameroon RO Romania

DE Germany, Federal Republic of SE Sweden

DK Denmark SN Senegal

FR France sυ Soviet Union

GA Gabon D Chad

GB United Kingdom TG Togo

HU Hungary US United States of Ameπca

JP Japan P Democratic People's Republic of Korea

S P E C I F I C A T I O N

STAC ABLE CHAIR

Background of the Invention

This invention relates to an improved stacking chair and to a frame therefor.

In the past, stackable chairs have usually been so designed that when nested in a stack there was considerable vertical space between them, often two or three inches. As a result, only a few chairs could be put into one stack; moreover, stacking them and removing them from the stack was difficult. Compact stacking has been rare; although it has been achieved with special structures.

Another difficulty with many stackable chairs was that in each the frame was made up of several frame members. If these frame members were strong, they were usually relatively heavy; if they were light in weight, they were usually not sufficiently strong. Such chairs usually required a front horizontal stretcher to provide sideways stability, especially when the leg members were thin. This sometimes was uncomfortable in that the back of the sitter's legs would hit this front horizontal stretcher bar.

Heretofore, stackable chairs were especially heavy because they required such extra frame members. Stackable chairs made of steel tubing heretofore typically required either a stiff frame member or stiff shelf portion across the top of the back and another stiff frame member or stiff shelf portion across the front of the seat. As an alternative, the seat and the back had to be so rigid that they would provide the needed strength. The more rigid the seat or back was, the less comfortable it was.

Another problem with stackable chairs was their rigidity. This problem relates even to the chair disclosed in my earlier issued U.S. Patent No. 3,845,986, which is otherwise excellent. In other chairs, too, rigid members or portions at the top or across the seat or across the legs

added to the discomfort of the user. In some cases, a top bar across the back is convenient to the people who move the chairs from one place to another, but it does detract from the comfort if the sitter's back can come against it. Such rigidity was thought necessary to strength and stability, but it has tended to prevent a chair from being able to leve itself on uneven floors. This has had particular disadvanta when such chairs were used in outdoor cafes, where stack- ability is very desirable, but where the ability of the legs to level to uneven surfaces made the chairs awkward, uncom¬ fortable, or annoying to the users. Conventional rigid fram chairs have tended to rock on such uneven surfaces and, therefore, to bring the chairs into the minds of the users f too often.

Heretofore, stackable chairs, when stacked, have usually resulted in the frame of one coming against the fram of the other. Often this has done so in a manner such as to scratch the frames or to scrape off their finish. If they were spaced apart vertically so as to protect the finish so much space was left that the stack could not be compact, as remarked earlier.

Chair frames that utilized stretched textiles have usually required lacing means to take up the gap after the fabric had been used for some time and had sagged or develop excess width; if no such lacing means was employed, the seat and backs soon became very baggy and sloppy-looking.

Among the objects of the present invention are tho of solving the problems enumerated above. Thus, it is an object of this invention to provide a comfortable, compactly stackable chair; to provide stackable chairs that do not need to incorporate a front, horizontal, rigid stretcher, especially one between the legs; a chair that is not completely rigid so that it can flex sufficiently to accom¬ modate itself to an uneven floor; to provide a stackable

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chair which can be relatively light in weight; to provide a stackable chair in which the frame members of each are protected from scratching and from rubbing together; to provide a chair that can utilize many kinds of seating material, including fabric seating, without developing the bagginess and sloppy appearance but in which slack is automatically taken up by the chair.

Other objects and advantages of the invention will appear from the following description.

Summary of the Invention

The Invention comprises a stackable chair and a frame for such a chair. The frame includes a main frame element comprising a U-shaped horizontal portion and a pair of vertical front legs. The U-shaped portion has a rear, horizontal cross or lateral portion, joined at each end by." a corner to a horizontal side portion, each of which is respectively joined by a corner to a front leg. The front legs are substantially parallel to each other, and the side portions are generally parallel to each other but diverge slightly from-rear to front.

The frame also includes a pair of rear legs, each with a back-support portion in line with the rear leg but preferably curving slightly rearwardly. These may be two separate members, but if desired, with somewhat less comfortable results, the two members may be replaced by a single member having a lateral member running across the upper end of the back portions. The back-support portions are generally parallel to each other, but when they are part of two separate members, they preferably diverge slightly as one moves upwardly.

The frame members are secured together by a pair of cupped frame juncture and spacing members, each of which is shaped as a generally triangular-looking cup with a

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horizontal top and a pair of vertical depending sides. The top has a pair of horizontal edges and each vertical side has a pair of vertical edges at each end. A wider horizont edge and two of the vertical edges are welded to the sides the main frame element adjacent to the corners by which the cross member merges into the side members, thereby providin sidewaise spacing. The other horizontal edge and twoverti edges are each welded to a rear leg. This places the rear legs and back-support portions outside the front legs, so that they are sufficiently farther apart from each other than are the front legs, thereby making the chair stackable

A seat, preferably non-rigid and resilient, bridg and is secured to the two side portions of the frame and urges them toward a truly parallel relationship,- while, similarly, a back, also preferably non-rigid and resilient, bridges and is secured to the two back-support portions and urges them toward a truly parallel relationship. These sea and back portions may be made from the materials shown in U. S. Patents numbered 3,720,568 and 3,843,477. When that material is used (usually sold under the name SOFLEX ^® ) then an especially, comfortable and resilient seat is obtained. The SOFLEX ^® seat or back may be covered or encased in additional fabric. In place of this preferred seating material, ordinary fabric may be used when properly designe Wood, metal, plastic,,and other rigid seats and backs may b used, especially in a special form of this invention.

To prevent the frame members from becoming scratc during stacking, each frame side portion may be provided wi two plastic members secured to or projacting from a lower surface of the side portions, one preferably near the front and the other preferably near the rear. One of these faces inwarldy and the other faces outwardly, to provide a kind of locking engagement, effective to space the successive chairs slightly apart so that they rest on these non-scra c plastic members but are still compactly stacked.

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The frame elements are metal and all may be made of the same tubular stock, if desired. When tubular stock is used, a bottom glide may be inserted into the tube and may comprise a plastic member with an outer portion substan¬ tially the same diameter as that of the leg.

If somewhat more security against inward collap¬ sing of the seat portion is desired, this can be achieved without losing the flexibility of the frame by a steel rod or tube bridging between the forward parts of the side portions but not rigidly connected to them. The rod fits into a respective opening through a wall of a side portion and may bear against the wall opposite to the opening, but the rod is not welded to the side portions, so that the rod is still free to move somewhat in the opening, thereby enabling the frame to flex. For that purpose, the opening is made somewhat oversize.

Other features will appear from the following descriυtion.

Brief Description of the Drawings In the drawings:

Fig. 1 is a view in perspective of a chair embodying the principles of the invention and incorporating a chair frame embodying the principles of 'the invention.

Fig. 2 is a partially exploded view of the chair of Fig. 1 showing the assembled chair frame and, separated, the seat and the back; the seat member has been broken off to conserve space.

Fig. 3 is a bottom view of the chair of Fig. 1.

Fig. 4 is a perspective view from one side of the chair frame of Fig. 1.

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Fig. 5 Is a perspective view from behind and above showing a chair employing the same frame as that of Fig. 1 but with a modified seat and back.

Fig. 6 is a view in perspective of the chair of

Fig. 5, looking from the rear.

Fig. 7 is an exploded view of the frame of the chair of Fig. 1, showing each element separately.

Fig. 8 is a view in side elevation of a stack of chairs like that of Figs. 6 and 7, supported on a transporting dolly.

Fig. 9 is a view in front elevation of- the stack of Fig. 8.

Fig. 10 is a top view of a left-hand, frame- connecting-and-spacing member employed in the chairs of Figs. 1-9.

Fig.- 11 is a view in rear elevation of the frame- connecting-and—spacing member of Fig. 10.

Fig. 12 is a right side elevation thereof.

Fig. 13 is a left side elevation thereof.

Fig. 14 is a front view thereof.

Fig. 15 is a fragmentary view in rear elevation of segments of three chairs of Figs. 1-9 in a stack showing the frame-connecting-and-spacing member of Figs. 10-14 connecting two frame members of each chair together.

Fig. 16 is a fragmentary view in side elevation of the left side of the same portion of the same three chairs.

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Fig. 17 is a fragmentary enlarged view in perspective of a portion of the frame of Figs. 1-3, showing how a frame-juncture-and-spacing member joins a rear leg to the main frame element and spaces the rear legs apart farther than the side portions and front legs.

Fig. 18 is a view in section taken along the line 18-18 in Fig. 17.

Fig. 19 is a view in section taken along the line 19-19 in Fig. 18.

Fig. 20 is a view in perspective of a chair like that of Figs. 6 and 7 showing how the frame is able to adjust to an uneven surface so that the frame will be stable even on an uneven surface. The left front leg is shown elevated on a block, and a weight is shown on the seat to illustrate that the weight, by flexing the frame, achieves the needed adjustment of the frame.

Fig. 21 is a view in side elevation of the chair

Fig. 22 is a view like Fig. 21, but here the left rear leg is the one that is supported high.

Fig. 23 is an enlarged fragmentary view, partly in vertical section, of a portion of three stacked chairs, taken along the line 23-2.3 in Fig. 24.

Fig. 24 is a view partly in horizontal section of the portions shown in Fig. 23, taken along the line 24-24 in Fig. ^' 23.

Fig. 25 is a further enlarged view partly in vertical section through the front of the stacked frame side portions, looking rearwardly and showing the two spacer

members which keep the frames from scratching each other during stacking and unstacking.

Fig. 26 is a still further enlarged view of a portion of Fig. 25.

Fig. 27 is a view in vertical section taken through the side rails of two chairs, looking rearwardly, with the two about to be stacked, one being inclined down from the rear and the other upwardly from the rear.

Fig. 28 is a perspective view of a modified form of chair frame of this invention in which a free-floating rod or tube is placed in a non-rigid manner across the two side portions.

Fig. 29 (on the same sheet as Figs. 17-19) is a view in section along the line 29-29 in Fig. 28 illus¬ trating an unflexed position.

Fig. 30 (on the same sheet as Figs. 17-19) is a view similar .to Fig. 29 illustrating a flexing position that can be obtained in the same structure.

Fig. 31 (on the same sheet as Fig. 28) is a view in perspective of another modified form of frame of the invention having only two main frame elements plus the - juncture and spacing members, the back-supporting portions being joined at their upper ends.

Fig. 32 is a view in rear elevation of a chair frame like that of Figs. 1-3 showing divergence of the back-supporting portions from each other before the back is secured thereto.

Fig. 33 is a similar view from the rear showing how constant tension is exerted when the frame of Fig. 32 i provided with its back, in this instance a fabric such as ca

Fig. 34 is a top plan view of the same chair frame showing the divergence of the side portions from the rear to the front, before the seat is secured in place.

Fig. 35 shows the frame of Fig. 34 with the seat in place, showing how constant tension on the textile is maintained by the frame.

Fig. 36 is a view in section taken along the line 36-36 in Fig. 35, showing a stretched textile put around the frame and stitched there, instead of using the types of seat shown in Figs. 1-3, 6 and 7.

Fig. 37 is a view similar to Fig. 28 showing a modified form of textile seat, with the stretched textile slid into channels of a frame adjuvant instead of being secured around the frame by sewn loops.

Fig. 38 is an enlargement of a portion of Fig. 37 showing the rod securement in more detail.

Fig: 39 is a view similar to Fig. 37 showing a modified form c3f the chair of this invention having a rigid seat, as of metal, so suspended as to preserve flexibility in the frame.

Fig. 40 is a view like Fig. 39 with the chair frame shifted relative to the seat, as compared with Fig. 39.

Fig. 41 is an enlarged view of one side portion of Fig. 39.

Fig. 42 is a view similar to Fig. 39 of another modified form of the chair of this invention, wherein a plywood seat is secured in another manner permitting flexure of the frame relative to the seat.

Fig. 43 is a view like Fig. 42 with frame flexure illustrated.

Fig. 44 is a view similar to Fig. 16 but showing a modified form of frame-connecting-and-spacing members.

Fig. 45 is a view in section taken along the line 45-45 in Fig. 44.

Fig. 46 is a view in section taken along the line 46-46 in Fig. 44.

Description of Some Preferred Embodiments The chair in general (Figs. 1-6) :

Fig. 1 shows in perspective a stacking chair 50 embodying the principles of the invention. As can be seen from this view and from Figs. 2 and 3, the chair 50 has a frame assembly 51, a seat 52, and a back 53. The seat and back assemblies, as has been said earlier, employ the struc ture shown in my U. S. Patents numbered 3,720,568 and 3,843,477. This is preferred because that structure is excellent for seats and backs; however, as will be seen later, it is not essential.

Figs. 5 and 6 show a stacking chair 55 very much like the chair 50 and. incorporating the frame assembly 51 but having a modified form of seat 56 -and back 57. The seat 56 and back 57 may actually be the seat 52 and back 53 encased in a fabric covering, either with or without som additional foam or plastic foam upholstery. However, they may represent a different kind of seat and back.

These views show that the frame 51 of this inven¬ tion is adapted to many different kinds of seat and back arrangements. As will be seen later, however, it is more desirable to have the seat and back be of non-rigid materia than it is to have them of rigid material. The seats 52 and 56 and the backs 53 and 57 are especially comfortable _m m

and are highly recommended whether as shown in Figs. 1 to 3 or whether incorporated in a fabric case so that they would appear as in Figs. 5 and 6. The use of simple fabric seats is also feasible, as is the use of wood, plastic, or metal seats.

The frame assembly 51

(Figs. 3, 5, 8-19, and 32-35) :

Fig. 5 is an exploded view of the frame assembly 51 and shows all the elements of that frame. The frame assembly 51 includes as principal ingredients a main frame element 60, two other frame elements 61 and 62 which comprise the rear legs, and frame-connecting-and-spacing members 63 and 64.

The main frame member 60 has a horizontal U-shaped portion from which the front legs depend. Thus, it has a rear horizontal cross, lateral, or stretcher member 65 joined to side rail portions 66 and 67 by rounded corners 68 and 69; and these side members 66 and 67 are joined at their forward end by two front legs 70 and 71 by rounded corners 72 and 73. Thus, the entire main frame member 60 may be made from a single piece of metal tubing bent to shape.

The two rear leg members 61 and 62 are preferably identical, each of them having an upper back-supporting portion 74 and 75, each preferably having a rearw ^' ardly inclined portion 76 or 77.

The very important frame-connecting and spacing members 63 and 64 are illustrated in enlarged form in Figs. 10 ^v to 19, 23 and 24. They are symmetric to each other and, when attached, are cup-like in shape and, from above appear somewhat trapezoidal. Thus, it has a generally trape¬ zoidal, essentially flat, upper horizontalwall portion 80 from which depend vertical side walls 81 and 82, via downwardly

curving corners. At the opposite ends of the upper wall 80 are a long, mostly curved horizontal edge 83 and a shorter semicircular horizontal edge 84. The edge 84 has a radius to fit its leg member 61 or 62 and is welded thereto The edge 83 is curved to match the curve 68 or 69 where it abuts it. The vertical side walls 81,82 have vertical edges 85, 86, 87, and 88. The edge 83 and the edges 85 and 87 form a continuous edge which Is welded by any suitab welding technique to the main frame member 60. The locatio is important, and the connecting members 63 and 64 are continuously shaped to fit the frame member 60 at an exact spot, near and along part of the corners 68 and 69 and preferably including a portion thereof, but also partly alo the rear end of the side members 66 and 67 so that the members 63 and 64 will act to space the rear legs 61 and 62 out laterally from the frame 60. The edges 86 and 88 may b straight, to abut the rear leg 61 or 62, but the edges 85 and 87 are curved to match the contour of the side rail 66 or 67 and other portions of the frame 60 they are to abut, as shown at 89 and 90. The securing to the rear legs 61 and 62 is done along the edges 84, 86, and 88, which also lie as a continuous edge, and again, welding is used.

The result is that the members 63 and 64 and the welding provide the sole rigid connections between the shap frame members. Thus,. the two connecting and spacing member 63 and 64 rigidly connect the rear legs 61 and 62 to the frame member 60 at a point near the back thereof and spaces the rear legs 61 and 62 out laterally sufficiently so that the chair 50 or 55 can stack. The legs 61 and 62 are therefore farther apart than the legs 70 and 71 at the fron at least'by the thickness of the frame members. To assure maximum strength of these Important connections, all of the joining edges 83, 84, 85, 86, 87, and 88 are welded throughout their full length to the frame tubes 61 and 66, 68 or 62 and 67, 69. The welding is all done from below and inside the box-like configuration, so that the whole

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gives a clean appearance, eliminating the need for finishing off the welds, shown at 79.

Figs. 15 and 16 show some interesting features relating to the members 63 and 64. The vertical extent of the contact between the member 63 or 64 and the rear leg 61 or 62 (along the edges 84, 86, and 88) is shown at

H 1 and is preferably greater than the diameter R9 ^Δ of the seat frame tubing. Also, the horizontal extent D ⁴ - of contact between the member 63 or 64 and the seat frame 60

(along the edges 83, 85, and 87) should be greater than the

2 2 2 diameter D of the seat frame tubing. Preferably, D =H , and the thickness of the metal members 63 and 64 is the same as that of the members 60, 61, and 62, to assure evenness in temperature during welding. The spacing must be sufficient to achieve the difference between the distance between the rear legs and that of the front legs needed for stacking. The members 63 and 64 are so shaped and located that they do not interfere with the compact stacking and do not engage their corresponding parts on other chairs when the chairs are stacked.

It probably needs to be emphasized that this provision of these two simple connecting members which are symmetrical to each other, form the sole rigid connections of the frame members,, and that as a result there can be considerable flexibility in the portions of the frame 51 that are remote from these connecting members 63 and 64, even though the frame 61 is preferably made from tubular steel. For the frame 61 to be rigid there would have to be some additional members rigidly securing the front legs 70 and 71 together _^ ' or securing the side members 66 and 67 together. While such rigidity might be feasible, it is not considered desirable.

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As Figs. 32 and 34 illustrate the side portions 66 and 67 preferably diverge from each other to rear and front so that the distance between the front legs 70 and 71 is preferably at least 57_ greater than the distance they would be if they were truly parallel and to which they are usually held by the seat 52 or 56. Similarly, the upper ends of the back portions 74 and 75 preferably diverge from the connection members 63 and 64 so that the distance betwee them Is preferably at least 5% greater than the distance to which they are brought by the back 53 or 57 in the preferable constructions. This enables spreading and, as it will be seen later, the same absence from rigidity has advantages in enabling the user to sit comfortably on an uneven surface.

Adaptation to an irregular surface (Figs. 20-22).-

As Figs. 20, 21, and 22 show, the present inventio enables the chair 50 and 55 to adjust itself easily to an uneven surface. This is a very important feature of the invention made possible by the fact that the sole rigid connections between the frame member 60 and the frame member 61 and 62 is that supplied by the connection and spacing members 63 and 64. Thus, as shown in Figs. 20 and 21, the left front leg 71 is placed up on a block 100 and a weight 101 is set on the seat 46. The block 100 corresponds to an uneven surface, as on an outdoor terrace or sidewalk, ^• and the weight 101 corresponds to a sitter. As long as the weight 101 is at least about 25 kg, the chair 55 will adjust itself so that it will not feel tippy or unstable even though the bottoms of the legs are at different levels. The height H of the block 100 shown in Fig. 21, which is mad to scale, can be as much as one centimeter (ten millimeters) Fig. 22 shows that the same thing applies just as well for a rear leg 62 being the one where the rise in the ground surface is.

The stackability of the chairs (Figs 8 and 9) :

Figs, 8 and 9 show that the chairs 50 or 55 can be made very compactly stackable. The actual stack height per chair depends on the thickness of the frame members and on the spacing between them, which is kept quite close. Generally speaking, the seat 52 or 56 and' back 53 or 57 are made thinner than the frame 51 and do not enter into consi¬ deration for compactness of stacking. As shown, the stacked chairs in large groups are preferably supported on a dolly 91 having an inclined portion 92 and inclined back 93 for supporting both the front and rear legs of the bottom chair and a portion of the rear legs leading up at the back. The subsequent stacking is then supported by the dolly 80 which, having wheels 94, can be moved from place to place.

Spacing during s acking (See Figs. 7-9 and 25-27) :

The stacking, as shown in the drawings, calls for a buffering or spacing of the successive frames 51 from each other by a small amount in order to prevent the frames 51 from scratching each other during stacking and unstacking. For this purpoδ ^' e, a pair of plastic separators 95 and 96 are used on each side frame member 66,67. The separators 95 and 96 are preferably identical, and they may be in the form of hole plugs secured to themain frame member 51. Preferably, they are located on the side members 66 and 67, one being located near the front thereof and the other near the rear, as shown in Fig, 3. In each instance, a hole 97 is drilled through the side member 66 or 67 to take each separating member 95,96. The members 95 and 96 are preferably made of plastic, and each has a rounded head 98 and a generally conical stem 99 with a pair of flexible fins 102 that hold the stem 99 in place once it is inserted through the opening 97. Thus, the fins 102 tend to fold to permit entry of the stem 99 into the opening 97, but once through the opening 97, the fins 102 are difficult to retract. Only the heads 98 project from the openings 97, and they are

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held in place by the stem 99 and fins 102 so that they are held very close to the frame member, projecting only a sufficient amount to prevent the frames 51 from touching each other. These two plugs 95,96 on each side are set so that one (either one) faces inwardly of the chair frame 51 and the other faces outwardly, providing a trough betwee them that helps to keep the stacked chair frames 51 verti¬ cally aligned while at the same time providing the needed protection against abrasion. Thus, the distance D,, shown in Fig. 26 is the distance between the point where the separator 95 bears against the chair frame member 67A below it and the actual top of that frame, while the distance D, is the spacing between the two frame members 67 and 67A as a result of this expedient.- Therefore, as can be seen from Figs. 23 to 25 (as well as in Figs. 8 and 9), the stacking can be compact while direc-t frame contact is avoided. The spacing S is also shown in Figs. 16, and 17.

Glides (Figs. 3, 4, and 7) :

Suitable glides 103 may be used to support the chair, and if the stock is tubular, then the glides 103 may be as shown in Fig. 7, each having a stem portion 104 that is inserted up ^" into each leg and fits, snugly in the interio of the leg, and also having an exterior portion 105 which has preferably substantially the same diameter as the chair legs 61, 62, 70, and 71. This helps to make a very trim- looking chair.

Attachments for securing the SOFLEX ^® seats and backs (Figs. 2 and 7):

The chair frame 51 as shown in Figs. 2 and 7 is preferably provided with a pair of seat-securing members 10 and 107 and a pair of back-securing members 108 and 109. These members 106, 107, 108, and 109 are clip-strips welded onto the side frames 66 and 67 for the seat and to the back members 74 and 75 for the back and have projections 110 tha enable a rapid and secure affixation of the seat 52 or 56 a the back 53 or 57. Hooks on the ends of the seat 52 or 56

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and back 53 or 57 engage the projections 110, which then hold them in place. The projections 110 may then be crimped around the end hooks. The attachment of the seat and back urges the side members 66 and 67 and the back members 74 and 75 to a more nearly parallel position. This, too, is an important feature of the invention and flows partly from the members 63 and 64 providing the sole rigid frame connec¬ tions.

Use of a free-floating stretcher (Figs. 28-30):

As shown in Figs. 28-31, a free-floating stretcher rod 112 may be used to prevent any tendency of the chair 50 to collapse with soft upholstery. For this purpose, two openings 113 and 114 are drilled into the inside wall of the respective side members 66 and 67, and the rod 112, signi¬ ficantly smaller in diameter than either of these openings 113 and 114, is inserted to bridge the distance between the side members 66 and 67 and to extend into the frame to a position where it is capable of bearing against the opposite wall thereof. When the seat 52 or 56 is in place and no one is sitting on ^* it, the rod 112 prevents any tendency for the chair to be collapsed inwardly by abusive compressive forces; at the same time, since the connection is not rigid, it also perpetuates the frame's flexibility when the chair is being sat upon and enables the desired vertical movement for a type of knee action that enables the chair to adjust to uneven base surfaces, as just described above, the same dimension H shown in Figs. 20-22 being shown in Fig. 30.

A more rigid back for serving as a handle (Fig. 31) :

As shown in Fig. 31, the invention includes a chair 120. The two rear leg back-support members may actually be part of a single unitary tubular steel member 121 bent to provide two rear legs 122 and 123, back-support portions 124 and 125, and also a rigid stretcher member 126

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across the back. This is somewhat less desirable, because it adds weight to the chair, but it does have the advantage of helping people who are used to handling chairs by member across the back to move them around from place to place.

Use of the chair frame with fabric covering and how constant tension is maintained on that fabric (Figs. 32 to 38):

As Figs. 32 and 34 show, there is divergence from rear to front of the seat portion of the frame 60 and from bottom to top of the back-support members 74 and 75. When a stretched textile 130 is put around the frame members 66 and 67 and then sewn to itself along stitches 131 and 132 t provide loops 133 and 134, as shown in Fig. 36, the fabric 130 then brings the side frame members 66 and 67 together s that they become truly parallel (Fig. 35), and a similar fabric back 135 brings the back-support members 74 and 75 so that they become truly parallel (Fig. 33). This means that a constant tension is maintained on the textile member 130,135 which helps to keep the fabric stretched; and, there¬ fore, it is especially good for use with cloth seats 130 an backs 135 to prevent sagging and baggy appearances. The sam kind of alignment of the frame happens also with the SOFLEX type of seating; the tension is not needed by the SOFLEX ^® seat, but the spreading is effective in aiding comfort of t sitter.

As Figs. 37 and 38 show, the frame members 66 and 67, when using a textile seat 140, may be provided with members 141 and 142, each shaped somewhat like a question mark with a long straight portion 143 welded to the frame member 66 or 67 and the hook portion 144 extending out therefrom. Then a seat 140 which is prestitched and has thin rods 145 slid into pre-made stitched loops 146 can be placed in the hook member 144 and held in place by the tendency of the frame members 66 and 67 to space apart.

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Rigid seats and backs installed to enable frame flexure (Figs. 39-43) :

One of the most important features of the invention is the ability of outboard frame portions to flex. As the connecting and spacing members 63 and 64, the frame members are connected quite rigidly, but the outboard portions of the frame 51 (such as the front legs 70 and 71) and the upper back portion 76 and 77 can flex.

Rigid seats and backs can be installed on the frame 51 in a rigid manner, but this foregoes some of the leading advantages of the chair, nullifying most of its ability to flex, to adjust to uneven floors or terrain, and to adjust to sitters that shift their weight.

However, as Figs. 39 to 43 show, it is possible to installL rriiggiidd sseeaatts and backs in such a manner that the frame can still flex.

Figs. 39-41 show a sheet metal seat 150 provided at each end with a hook-shaped channel 151,152. Matching hook-shaped channels 153,154 (like the channels 141,142) are welded to the side rails 66 and 67 and interlock with the hook-shaped channels 151 and 152, preferably an elastic member 155,156 (preferably extruded in the shape illustrated) lies between the members 151 and 153 and the members 152 and 154. Thus, the rigid seat 150 does not greatly affect the ability of the frame 51 to flex.

Figs. 42 and 43 show a molded plywood seat 160 secured to a bracket 161 or 162 at each end by a screw 163 or 164, the brackets 161 and 162 being welded to the frame side rails 66 and 67. However, a block or disk 165,166 of elastomer enables the desired flexing action, as shown.

A modified form of frame juncture member (Figs. 44-46) :

In place of the connecting and spacing members 63 and 64, Figs. 44-46 show a connecting and spacing member 170, a metal plate with a single bend 171. The plate 170 thus constitutes two buttresses 172 and 173, the buttress

171 being generally vertical, while the buttress 172 is generally horizontal. The plate 170 should preferably be at least twice the thickness of the tubing wall thickness. One edge 174 of the vertical buttress 174 is straight and is welded to the leg 62. The other edge 175 of the buttres

172 is curved and is welded to the frame members 67, 69, an 65, as shown. One. edge 176 of the horizontal buttress 173 is arcuate and is welded to the leg 62. The opposite edge 177 of the horizontal buttress 173 is curved to follow the shape of the frame portion' 69 and is welded to the frame member 60, as shown. These welds are not so completely hidden as with the members 63 and 64, but are located as unobviously as possible. Thus, the desired strong rigid connection and also the spacing are provided. The angled edge 178 of the buttress 173 enables the stacking of the frames without striking the buttress 173 against another chair frame.

To those skilled in the art to which this inventi relates, many changes. in construction and widely differing embodiments and applications of the invention will suggest themselves departing from the spirit and scope of the invention. The disclosures and the description here are purely illustrative and are not intended to be in any sense limiting.

O A. "WI