FI61397B - SITS- ELLER RYGGSTOEDSDEL - Google Patents

Description

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FLUENT AND STRUCTURAL BOARD · / 44} Date of departure and date of issue. - is nK op

Patent and Insurance Administration Aiwaktn utlaad odi utl.ikrtftan pubMearad J * (32) (33) (31) IVydKty atuotttatia — BagM priori »· * 22.03.71 United States 62nd Street, New York, NY 10021, USA (US) (7M Leitzinger Oy (5M Seat seat or backrest part - Sits- eller ryggstödsdel

The invention relates to a seat or backrest part of a seat consisting of a plurality of arcuately tortuous or tortuous metal spring wires, each having two ends, all coming close to the wire immediately adjacent to it at frequent intervals, and a thin sheath-like plastic cover surrounding said wires and which follows the winding or twisting of the yarns and joins the yarns together at points where they pass close to each other so that the coating forms bridges between the yarns.

Such a seat or backrest part can be used in chairs, sofas, stools, benches, seats of cars or other means of transport and the like.

At best, a hard seat can only approach a comfortable shape because people’s weight and the shape of their sciatica vary greatly. Although the seats could theoretically be tailor-made for each person, this would be expensive and would require the seats to be transported wherever they would be used. A better solution to the problem is a seat that automatically tends to adapt to the shape of each user's buttocks. Thus, it is an object of the present invention to provide a seat that is properly resilient in the correct positions.

The body of a seated person rests mainly on the seat cushions, which are the two lowest points of the pelvis. In addition, it rests on fleshy and fatty meat tissue within a radius of 2.5 to 5.1 cm. The reason why a flat, hard surface quickly becomes uncomfortable is that the load is concentrated on a small area of the seat nodules and the meat immediately covering them is compressed with great force. Applying this load over a larger area provides a more comfortable space because the compressive force per unit area is substantially less. This is facilitated by the automatic shaping of the surface of the seat j so that it approximately conforms to the seat. On the other hand, spreading this area too wide, as is the case when the seat is too soft, results in the occupant sinking too deep and often also insecure due to the occupant feeling inadequately supported. It is often seen in cars where the owner has found it worthwhile to install wooden-striped cushions to make the seat more sturdy.

Dr. Bengt Äkerblom, an eminent Swedish expert on human postures, says in his book Standing and Sitting Posture, published by A.B. Published by Nordiska Bokhandeln in 1948.

"Naturally, a seat that is too soft distributes pressure over the seat pits better than a hollow and rigid one. However, they are so small that it makes very little sense to have a very soft and flexible seat. On the contrary, such a seat can be expected to transfer a significant amount of weight to tissues that are not The best consistency for the seat would therefore be such that, although it gives way under pressure, it does so only slightly. "

The right flexibility alone is not enough either. The freedom of movement of a suspended mat, which occurs in a bidirectionally flexible material, adapts better to the shape of the human buttocks, which is itself a composite arch.

While some spring and cushion combinations can provide the right yield strength and strength, virtually all cushions have the fault of being good thermal insulators. In a cold room, this may be acceptable on a temporary basis, but people usually wear clothing that matches the temperature conditions, and sitting on a heat-insulating material for a long time becomes uncomfortable because evaporation of body temperature is prevented in the back of the person. To get to a cooler place, the person twists. Anyone who wears a swimsuit has tried to sit on a convertible seat that has been in the sun also knows that such heat conditions in the seat can be unbearable.

Some previous seats have been made of separate wires, but the spacing between them has been such that too much load has been concentrated on too few wires, and this discomfort has made it necessary to use padded padding for such seats.

The ideal seat thus has: 1. The correct shape (including the right combination arch).

2. Proper flexibility and strength (flexibility allows the shape to adapt to each occupant).

3. Proper heat dissipation.

4. Correct surface contact area.

It is an object of the present invention to provide a seat which is closer to an ideal seat than previously achieved and which can be easily adapted to a wide variety of seat frames in different applications.

4 61397 To achieve this purpose, the seat or backrest part of the seat according to the invention is characterized in that the spring wires and the cover are formed as a separate seat or back straightens when the unit is mounted on the chair frame, where the straightening causes the spring wires to tension along the lowered cylindrical arch.

The invention can be considered as an improvement on the earlier U.S. patent 2,803,293. In this patent, each meandering spring had a hook at each end that partially surrounded the rigid frame body. This use of the hooks definitely did not prevent the wires from moving relative to the frame and did not hold them in place with respect to each other before coating them with plastic. In part, because at best there was only line contact between the wire and the frame (and unless the chair frame size was exactly matched to the hook size, the contact occurred at only two points), the hook tended to rotate when force was applied to it, e.g., when someone sat on the chair. Even after the chair was covered with plastic, this instability was such that when seated on top of the chair, the wire hooks tended to travel along the frame of the chair as the occupant moved into position. In this case, the seat area was distorted with the result that the seat became uncomfortable. The chair according to this patent was too expensive to manufacture because the springs had to be placed one by one and carefully in place and then either the whole chairs had to be recessed or at least the top of the chair had to be recessed from the seat. Such immersion meant that all parts of the chair that were embedded became coated with plastic, unless something could be placed on some parts of the chair 5 61397 to repel the plastic. Both options significantly increased costs. The coating also made the look of the chrome-like furniture unfortunate and the wooden furniture got a rather uncomfortable look. Each chair had to be made individually and the springs themselves had to be placed in the finished chair frame one by one so that the easy handling required for mass production was not possible. In addition, great care had to be taken that the spring manufacturer did not turn the springs themselves during its manufacture; otherwise the springs could not be properly bridged with plastic.

The present invention overcomes these difficulties, making mass production entirely possible. Only the seat unit or backrest unit is recessed and the combination is relatively inexpensive and can be made automatically and by other mechanical means. A very important feature is the use of a sub-combination that can be used on many different frames for different quality and differently designed seating units. The same subassembly can be sold to different manufacturers for attachment to any of a number of different frames.

A further disadvantage of the previous chair was that the seat and back of the chair were substantially planar and, although slightly curved, were installed with the spring in a superficially flat resting shape with little spring tension or cushioning effect. The present invention makes it possible to provide more tension, cushioning and flexible support from the springs by making the unit a cylindrical segment that is somewhat flattened when placed on the chair frame instead of making chairs from a series of substantially flat springs. The tension of the retraction springs is one of the main forces that hold the combination in place.

Another important feature of the invention is the use of bidirectional elongation, which is achieved by using plastic coatings with a Shore durometer value in a certain range. The springs can continue to bend in the usual way without restricting the coating on top, and the spring combination can also bend and stretch the plastic as it forms bridges between the wires. In the previous patent, it was possible to use a variety of materials, including hard molds, such as nylon, which certainly held the yarns together but did not stretch themselves, so that stretching had to be achieved with the yarns when using such a material. This gave the seat some flexibility, but usually on a cylindrical surface and not on the composite curve that emerged in a seat where the elongation is bidirectional. Such bi-directional elongation was also not observed or found in this type of chair until the desired range of durometer values was found in the present invention, used in proportion to the appropriate thickness of yarns, and thus this object was achieved.

Even bidirectional flexibility and proper wire thickness alone have been found to be insufficient. The ability to resist bounces is an important feature in considering the flexibility required for a comfortable seat, and is particularly important in vehicle seats where up and down movement tends to cause harmonic oscillations, as harmonic oscillations subject the occupant to horizontal oscillations for some time. over has been transported. Pop damping is thus necessary and is performed in part in the present invention correctly by selecting the durometer value of the plastic coating. If the durometer value is too low, the springs are too free and pop too easily.

If the value of the durometer is too high, the seat is too rigid and lacks the desired correct bidirectional elongation. Proper selection of the durometer value in accordance with the principles of the present invention allows the plastic to act as a shock absorber and dampen bounces.

The pops can be further damped in the present invention by using in combination some wires whose thickness, shape or spring tension or alloy differs from other wires in that their harmonic oscillation periods are different.

The amount of seat surface area taken up by the metal and the thickness of the plastic coating are also important features to be considered, and few, if any, of these features have been considered in the prior art. For example, in the drawings United States patent 2,803,293 for it can be shown that the metal having only about 14% of the surface area of the silhouette, while more recently, I have found that for proper results ^ p ^ siteräksen should be at least 17% of the surface area of 7 61 397 skyline, and preferably, although not this is not so important, up to about 75%, with the recommended range generally being about 17 to about 25%. The thickness of the coating should generally be about half the thickness of the wire to provide bridging, proper western secretion and proper flexibility, but a range of about 1/5 times the thickness of the wire - about the thickness of the wire can be used. The size of the void areas between the coated yarns should also not be greater than about 75% of the seat area used for one adult occupant, and should not be less than about 2%, with the recommended area being about 60-75%.

The present invention comprises a seat or backrest base which can be attached to different frames in different ways. In principle, the base is a cylindrical segment which is later flattened during installation to some extent, thereby tensioning the springs. Usually, though not always, it is a perimeter that usually has straight ends, typically parallel, connected by parallel sides made as circular arcs. These frames enclose a series of meandering spring wires, each of which is attached at its opposite end to the circumference, preferably to the end pieces. The wires run between the circumferential ends in a circular arc parallel to the circular arc of the parallel sides of the circumference. In most seats and backs, both of the two extreme spring wires are tangent to the second circumferential side in each ring, and each wire contacts or goes close to its adjacent meandering spring wire at least once per tire.

The thin sheath-like plastic coating surrounds both the circumferential wires and the meandering spring wires and follows the meandering shape of the spring wires and forms a bridge between them and connects them where they are tangential or in contact with each other. This thin plastic cover, although it leaves most of the seat area open between the wires, connects the wires and the perimeter together into a unit combination that is cylindrical in shape. When the unit assembly is mounted on the frame as either a seat or backrest, it is flattened somewhat but not completely. When using the seat, the pitch at one and the other end is opposite to SKf S .f s 8 61 397

After flattening, it is preferably between 0.64 and 2.54 cm. For clarification, the arc may be somewhat larger, preferably a radius of 17.8 to 27.9 cm. The value of the blanket Shore A durometer is preferably 45 to 90 and the best value appears to be about 7 5 so that. the bidirectional elongation referred to earlier is achieved.

In some embodiments of the invention, other circumferential shapes are used, and in other embodiments, no circumference is necessary as such, but is replaced by a special welded subassembly.

It should be noted that in the present invention, the wires cannot run directly 1 apart. They must be wavy in order to be stretchable. In addition, they need to be interconnected in a flexible way. This is contrary to my previous patent, which allows the use of flexible joints but does not require stretch joints. A person weighing 68 kg who normally sits in a chair according to the present invention thus weighs at least 2.5 cm (or at least 1/13 of the height of the combination) and at most about 7.6 cm (about 1/6 of the height of the seat). As mentioned, the joints are stretchable and flexible, but they are also so tough that they cannot be pulled apart under normal sitting conditions. Mixed and plasticized rubbers (putty and kneaded erasers) are rubbery in quality, but do not have the required elasticity, elongation, flexibility $, and flexibility. In order to obtain the best results in the present invention, the surface area of the silhouette of the yarns should be at least 17% of the seat area, especially the typical area, before coating. In order to achieve sufficient bridge formation, Lärn discharge and surface cushioning, the coating should be at least 20% of the wire diameter. If the seat were made only of springs, the comfort would be insufficient, especially when used in moving vehicles. That would be too crunchy. The correct durometric value of the coating and the correct thickness with respect to the thickness of the wire help to prevent this elasticity. The reason is similar to the reason why a car is not comfortable with metal springs alone, before it can be comfortable it also needs rubber, air and hydraulic fluid as a combination of pneumatic rubber tires and hydraulic shock absorbers.

In the drawings:

M M

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Figure 1 shows a perspective view of a chair embodying the principles of the invention.

Figure 2 is a perspective view on an enlarged scale of a chair or back unit or subassembly that embodies the principles of the invention before the unit is mounted on the chair frame of Figure 1.

Figure 3 is a section along line 3-3 of Figure 1.

Figure 4 shows a perspective fastening device used in Figures 1 to 3 to fasten the subassembly of Figure 2 to the chair frame in Figure 1.

Fig. 5 is a schematic side view showing the difference between the radius of the cylindrical combination of Fig. 2 and the radius of the mounted seat of Fig. 1 when the latter seat is somewhat flattened and thus the spring wires are tensioned.

Fig. 6 is an enlarged fragmentary perspective view of a corner portion of the assembly of Fig. 2 with the assembly somewhat flattened. Some parts have been broken away to show other parts that would otherwise be hidden.

Figure 7 is a further enlarged section along line 7-7 of Figure 6.

Figure 8 is a section along line 8-3 of Figures 6 and 7.

Figure 9 is a section along line 9-9 in Figure 7.

Fig. 10 is similar to Fig. 7 showing how the springs can be mounted from the opposite direction on the same circumferential unit.

Fig. 11 is a bottom plan view of a portion of the modified combination of the general type of Fig. 2 with some portions broken away.

Figure 12 is a section along line 12-12 of Figure 12.

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Fig. 13 is a sectional view taken along line 13-13 of Fig. 11.

Fig. 14 is a bottom section similar to Fig. 11 of a modified form of the circumferential body.

Figure 15 is a section along line 15-15 of Figure 14.

Figure 16 is a perspective fragmentary view of the chair frame.

Fig. 17 is a further enlarged sectional view taken along line 17-17 of Fig. 16 with the chair frame omitted.

Fig. 18 is a further enlarged sectional view taken along line 18-18 of Fig. 16.

Fig. 19 is similar to Fig. 18 showing the installation of the same unit assembly on a modified shape of the chair frame.

Fig. 20 is another view similar to Fig. 18 showing the installation of the same unit assembly on another modified shape of the chair frame.

Fig. 21 is a perspective partial view and partly in section of another modified form of unit assembly.

Fig. 22 is a section along line 22-22 of Fig. 21.

Fig. 23 is a section similar to Fig. 22 showing the same parts at an earlier stage of the combination.

Fig. 24 is a similar view showing a step of the combination between Figs. 22 and 23.

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Figure 25 is a perspective fragmentary view of another form of unit assembly.

Fig. 26 is a sectional view taken along line 26-26 of Fig. 25.

Fig. 27 is a similar sectional view of the unit of Fig. 25 inserted into the chair frame.

61397 11

Fig. 28 is a perspective view of a modified form of unit assembly having a circular perimeter shown flattened to the position it has attached to the chair frame.

Fig. 29 is a perspective view of another modified form of unit assembly in which the perimeter is omitted and the springs are secured together by a series of welds with the parts flattened into an arc in which they are attached to the chair frame.

Fig. 30 is a perspective fragmentary view of a portion of another modified form of the unit assembly.

Fig. 31 is similar to Fig. 30 of another modified form of unit assembly.

Fig. 32 is a perspective view of a modified form of the chair embodying the principles of the invention.

Fig. 33 is a front view of a unit assembly for a chair seat such as Fig. 32.

Fig. 34 is a side view of another modified form of the chair embodying the principles of the invention.

Fig. 35 is a front view of a unit assembly for a chair seat such as Fig. 34.

Fig. 36 is a fragmentary sectional view showing how the seat assembly and the chassis assembly are both secured to a single frame member in the chairs of Figs. 32 and 34.

Fig. 37 is a perspective view of a modified chair shape that embodies the principles of the invention and in which the seat and back assembly are mounted in a frame so as to form composite curved surfaces.

Fig. 38 is a side view of the chair of Fig. 37.

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Fig. 39 is an enlarged and schematic top view of two halves illustrating the bidirectional stretching effect of a wire and plastic combination.

Fig. 40 is a side view of an opened folding chair embodying the principles of the invention.

Fig. 41 is a side view of the folding chair of Fig. 40 Installed.

Fig. 42 schematically shows the relative arcs and radii of the backrest and seat for the chair of Fig. 40.

Figures 43-51 show from above all parts of different patterns of arcuate meandering bodies, in which case in all cases some of the wires shown are uncoated and the plastic joins the spring pieces together. The various figures are intended to be examples of the numerous figures that are possible in this invention.

Fig. 52 shows a front view of the principles of the invention in the lower part of a modified form of the chair.

Fig. 53 is a side view of a stool in another modified form that embodies the principles of the invention.

Description of some preferred embodiments

Example of a chair according to the invention (Figure 1)

A wide variety of * types of seating units can embody the principles of this invention, including chairs, sofas »Davenport sofas, benches, stools, car seats, bus seats, camp chairs, etc.

Figure 1 shows a chair 60 for the purpose of providing an example of a type of seat unit that may embody the principles of the invention. This example is not to be construed as showing all types of seating units or even all types of chairs whose frame structure, appearance, etc. can vary widely. The basic part of the present invention M 6 13n 139797 mainly relates to the seat and back unit and not to the frame of the chair itself.

The chair 60 has front legs 61, 62 and hind legs 63 and 64 which extend upward, preferably at an angle, and form back frame portions or pieces 65 and 66. The number of pieces used to make the chair frame is not important to this invention, nor whether the frame is integral or whether the pieces are welded or otherwise fastened together insofar as the present invention is concerned. Horizontal frame side portions or members 67 and 68 connect the front legs 61 and 62 to the hind legs 63, 64 where they meet the back frame members 65 and 66. The use of reinforcements and tops is not important in this invention, although some such members are shown in the drawing and there must be some rigid bodies to keep the frame pieces 67 and 68 separate and the frame pieces 65 and 66 separate. In this particular embodiment of the invention, the back frame pieces 65 and 66 are kept rigidly parallel to each other and the frame side pieces 67 and 68 are kept rigidly parallel to each other. This parallelism does not always have to be, but it is recommended.

The seat unit 70 is supported by the frame side pieces 67 and 68 and the back unit 70A is supported by the frame pieces 65 and 66. The seat unit 70 and the back unit 70A are very similar to each other; they may be identical in some cases, but usually the back unit 70A is somewhat smaller than the unit seat 70 and is usually made of a smaller thickness of wire.

The structure of units 70 and 70A is very important in this invention. Likewise, the units 70 and 70A are attached to the chair frame.

Seat unit 70 (Fig. 2)

Figure 2 shows the seat unit 70 before it is connected to the chair; the figure also shows in principle what the unit 70A looks like, although the unit 70A may be different in size or even structure or appearance if desired.

In this example, the unit 70 includes a perimeter 71 having spaced straight ends 72 and 73 connected by parallel side members 74 and 75 which are circular in shape. To avoid confusion for the reader, it is noted that the straight end pieces 72 and 73 are attached to the side of the chair frame pieces 67 and 68 and thus extend from front to back on each side of the chair GO, while the side pieces 74 and 75 are the front edges of the seat 60. in the case of a seat unit 70, the pieces 72 and 73 are ends and the side pieces 74 · and 75 are curved or circular sides.

Extending from both ends 72 and 73 from end to end are a plurality of meandering spring wires 76, 76a, 76b ... 76n which are inherently curved into a circular arc of the same size and shape as the side members 74 and 75. These springs 76, 76a, etc. may be of various shapes, some shapes is shown in Figures 43-51.

They can be called non-sagging type springs and are sometimes sold under the trade name No-Sag. Typical wires 76, etc. of this type are made of a steel spring with 0.60 to 0.75% carbon and 0.90 to 1.20% magnesium. Tensile strength is typically about 2,15050 to 18,550 kg / cm and their Rockwell hardness is in the range of about 33 to 41 RC. The diameter of the wires 76, etc., is designed to be between 1.27 and 3.81 mm. Too thick a wire tends to concentrate the stiffness too much and the seat is too sturdy, while a wire that is too thin makes the seat too soft.

Both ends 77, 78 of each spring 76 (see Figures 6-15) are firmly anchored and secured to the second end piece 72, 73 of the circumference 71. Various devices are used to achieve this strong anchoring and some of them are described later in the following sections. These include abrasion grippers and welding as some of the various types of mechanical joints.

The spring grooves 76, 76a, 76b ..... 76n are arranged tangentially to each other, with the two extreme spring wires 76 and 76n being substantially tangential to each other side 74 and 75 in each ring. Each thread 76 contacts adjacent threads at least once per ring. The contact may be a real touch, or it may be an approximate contact or close, because as will be seen, the assembly 70 remains sized in such a way that it does not require any actual physical contact with the metal. W, t .Π · / 'v *: 15 61 397 touch at each tangent point, but it is always a very close relationship, although not a real touch.

A thin sheath-like plastic coating 79 surrounds the spring wires 76, follows their flexible shape, and bridges the wires 76, 76a>, etc., where they substantially contact each other. It is recommended that the plastic coating 79 be about half the thickness of the wire or between about 1/5 of the thickness of the wire and about the thickness of the wire. At the junctions, the thickness can usually be greater, although the wires themselves may contact each other. This plastic cover 79 also surrounds the perimeter 71 and connects the wires 76 and the end and side pieces of the perimeter 71 together into a unit assembly 70. The plastic cover 79 holds the wires 76 together as they extend between the peripheral ends 72 and 73 and holds the side wires 74 and 75 in each of the extreme springs 76 and 76n. the tangent point. The result is an arcuate shape or a cylindrical arc shape, typically as shown in Figure 2, although the arc may be somewhat flatter or somewhat rounder.

Thus, the complete combination 70 is a unit that can be sold or shipped as a unit and that can be assembled into a chair according to Figure 1 or several other types of chairs, as long as the correct size and shape are matched in one way or another, i.e. either the chair itself can be shaped. that it fits with the unit seat 70, or the seat unit 70 may itself be made to fit either a chair frame or another type of seat unit frame. The unit 70 itself can be mass-produced and can be easily assembled into a chair or other seating unit by attaching both end pieces 72 and 73 to a suitable rigid frame.

Separate type of fastening device (Figures 3 and 4) This study considers various fastening devices, some of which are exemplified in Figures 16 to 20 and Figures 26 and 27. In principle, the fastening device may be an integral part of the unit 70 or 11¾ be an integral part of a chair frame or other frame. 97 to which the unit 70 is to be attached, or it may be a separate piece which is not an integral part of either of these. As an example of the latter type, a fastening piece 80 is shown in Figures 3 and 4. This may be a suitable metal or plastic part having a substantially tubular circumferential receiving part 81 through which an opening 82 fits tightly around the circumferential piece 72 or 73. The body 80 has a pair of flanges 83, 34 through which an opening 85 passes. As shown in Figure 3, the chair frame body 67 may have a series of openings 86 adapted to receive both sides 83 and 84 after the body 80 is attached to the peripheral body 72 or 73 around. A suitable screw 87 can then be inserted through a suitable opening 88 in the frame member 67 and secured to the sides 83 and 84 by the openings 85. As shown in Figure 1, a plurality of such units 80 may be used to secure the seat unit 70 and backrest 70A to the chair 60.

From this, it is apparent that one manufacturer can make the combination 70 and the combination 70A as units and sell to another manufacturer that makes the chair frames. as long as the dimensioning is correct, neither manufacturer needs to know exactly what the other teicet, kosxa unit 70, if done with the right dimensions, can be attached to several different types of chair frames, - or in fact other pieces of seat pieces, including benches, car frames etc. Unit 70 allows the chair manufacturer to secure the seat or back in place in the most attractive, comfortable, and practical way.

As will be seen in later sections of the report, there are very many ways in which the attachment of the body 70 to the chair 60 can be done, and the above is just one example.

Importance of cylinder arc flattening (Figure 5)

Fig. 1 schematically illustrates what happens when the unit 70 of Fig. 2 is placed in the chair 60 of Fig. 1. A circular cylinder arc of radius R1 according to Fig. 2 flattens from the shape shown at the bottom of Fig. 5 to the shape shown at the top of Fig. 5, where it has a larger radius R2. The span of the unit 70 is then wider and its arc is somewhat flattened so that it can be used as a seat. Its legal height is h, as shown in the drawing, and it is still a cylindrical, albeit much flatter.

This flattening of the round combination is. an important feature of the invention. Forming the unit 70 initially as a cylindrical arc that is quite circular and somewhat well closed and then flattening it considerably provides a large amount of desirable tension to the finished unit 70 so that the seat feels springy acting essentially as a large cushion and not simply a combination of thin springs. The exact value of the legal height h or curvature depends, of course, somewhat on the taste, but generally in a 40.6 cm wide seat unit 70 the legal height h is at most about 2.5 cm and the ratio can usually best be considered to be 1/64 to 1/16 of the span.

Also important is the amount of force required to flatten the seat, which is typically the size of a dining chair. For the purposes of the present invention, it has been found that compressing the springs in the assembly 70, which requires a force between 154 and 308 kg for flattening (preferably about 227 kg), provides a correct tension seat. This is the force used to pull both ends 72, 73 apart so that they are at the correct distance to fit over the chair frame members 67, 68.

Somewhat different rules apply to the back of the chair, and it should be noted that in the chair of Figure 1, as in most such chairs, the arch of the back extends backwards and is not Strong tending to flatten it; rather, he seeks to increase the curvature of the arc by decreasing its radius.

The tension of the inwardly pulling wires in both the seat and the back due to flattening is also one of the main forces that hold the wires in place.

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Meaning of plastic coating 79 (Figure 39)

The plastic coating 79 can be selected from various types of plastics, such as polyvinyl chloride, polyvinyl acetate, mixtures thereof, other vi-wrr.r i-61397 18 vinyl compounds, polyethylene »butadiene, acrylic elastomers, etc.

The substance may be transparent if desired or it may be nijime and give its own color one by one. It may contain a C - <- i. Dye or pigment which imparts the desired color completely, preventing the yarns 7 6 from appearing and giving the unit an appearance which gives the impression that it forms the actual seat material. The plastic coating 73 may be semi-transparent and may impart a hue or shade to the overall color.

It should be noted that in the present invention, the plastic is limited to the unit 70 or 70A and does not target the chair frame at all, so that the chair frame may have any surface or treatment desired that is not inconsistent with the nature of the plastic coating.

It is not advisable to weld the meandering wires 76 to each other at other tangential points, but to hold them together only by the plastic coating 79, whereby the wires 76 either touch each other or are also slightly separated from each other but going close to each other. The same applies to the connection between the wires 76 and the arcuate side pieces 74 and 75 of the circumference 71.

An important feature of the plastic coating 79 is that by selecting the correct area of the durometer. a bidirectional stretching effect can be obtained, as shown in Fig. 39. The springs 76 not only stretch in a known manner of non-sagging springs, but can also be stretched from the plastic cover 79 between adjacent springs 76, and this bidirectional stretching effect gives the seat a wide range of flexibility.

If the plastic 79 is too hard, virtually no such stretching can occur, and if the plastic 79 is too soft, too much stretching will occur, the springs 76 themselves will not be helpful enough, and the unit 70 may even tear off after a short period of use. By keeping the plastic coating Shore durometer within critical values, the effect is correct with sufficient rigidity, utilizing springs 76 and keeping them apart with sufficient flexibility so that the assembly is not simply surrounded by a rigid coating. I have found that durometrialue, which is critically necessary for this effect in a, is about 45 - about 90 Shore A durometer scale, the recommended value of about 75.

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Figure 39 has two parts. The left part depicts the part of the seat 70 before it is seated, whereby the springs 76 are therefore in their normal shape. A typical area 280 is insulated by the lines, comprising the wires 76 of one complete ring, so that the area represents the total area of the seat 70 in the case of a percentage of the metallic pattern per area. This area can therefore be used to determine exactly the shape of the wire and its average proportion of the seating area. If the thickness or yarn diameter is G, the length of the yarn can be determined by G by measuring the length of the biscuit lines of all the yarns 76 in the range of 280 G, and this value is found to be 34G. If the region 280 is itself 14.6G x 10.7G, i.e. 156.22G ^. The silhouette area of the wire in the area 280 is 34G ^, which is 21.76% of the area 280. This value is in the previously mentioned required area 17 to about 75% of the seat area and also in the recommended area 17 to about 25%.

Further, the voids between the coated yarns should be no more than about 75% and no less than about 2% of the seat surface area and the recommended range is about 60 to about 75%. A minimum value of about 2% gives hardly enough air circulation.

The wires 76 in the seat 70 are close to each other and almost in contact at points close to the tangent where the distance D1 between them, as shown in Fig. 39, can be as small as zero, and where the total distance from the outside to the outside is T1. The plastic coating 79 forms a bridge that secures the wires 76 together at 281 with a coating thickness of t.

The rightmost part of the shed 38 shows what happens when the chair 70 stretches, for example when sitting on it. The length L1 in the left part stretches to a longer length L2 in the rightmost part. The width W1 of the left part also increases to the width W2 in the right-hand part. The distance D1 in the left part is stretched so that it becomes the distance D2 in the right part, and the distance T1 is stretched to a distance T2. Thus, the importance of the bridge or junction 281 and the importance of the extensibility of the plastic 79 in this bridge or junction 281 are seen. This is of course also related to the thickness 7 of the plastic coating 79.

Λ-Ί .f. ΛΪ. . s 20 613 97

A glance at seat 70 might lead to the conclusion that the surface configuration would be tissue uncomfortable. However, this conclusion would be a mistake, as seat 70 functions differently than might first be inferred from the following reasons: (1) The average space occupied by a wire in a typical area (i.e., 17 to 75%) is so large that the human back receives support without concentrating too much . Conversely, if the wire takes up less than about 17% of the surface area (e.g., 14.4% of the area of Figure 2 in U.S. Patent 2,803,293), the seat would be uncomfortable in terms of fabric.

(2) The voids shall be at least 2% of the seat area in order to provide adequate air circulation, and the voids shall preferably take up much more of the seat area up to a maximum of about 75%.

(3) The wire 76 is not a bare metal alone, which would be highly thermally conductive and therefore unpleasant and uncomfortable. The wire 7G is sufficiently coated with a plastic 79 having low thermal conductivity; thus it is comfortable and comfortable to sit on.

(4) Coating 79 is in the Shore A durometer value range (45-90) that is neither too hard nor too soft; in fact, the paving itself tends to give some cushioning effect and its effect in bridges 281 increases comfort. Without this, seat 70 might be too hard or too soft.

(5) Thanks to the two-way elongation discussed above, the seat automatically adapts to the contours, providing minimal resistance to the rear of the person. Without this two-way stretch, the seat 70 could become increasingly uncomfortable.

Friction of the wires to the circumference (Figures 6-10)

Although a number of devices may be used to secure the spring 76 to the circumference 71, some of these are, of course, superior to others. The popularity depends on several factors, such as the capabilities and choices of the manufacturers, the details provided by the customers, and the various cost factors and capital equipment required.

21 61397

One type of fastening desired uses the friction lock principle, as shown in Figures 6-10. In this form, the circumference 71 has end pieces 72 and 73 which are substantially tubular; they may be made as a solid tube, but it is preferred, as shown in the drawings, that each body 72 or 73 be an open tube which may be made by turning a thin strip of metal into a substantially circular shape. As shown, the body 72 or 73 has a flat base portion 90 perforated at certain intervals to form holes 91 and sides 92 and 93 extending, for example, at an angle of about 30 °. Machines for making these can be easily designed, either batchwise or in a substantially continuous manner, so that the pieces 72 and 73 can be made in long strips cut to the desired lengths.

As can be seen by comparing Figures 7 and 10, body 73 can be considered the same as body 72, so it is raverible; i.e. the same piece can be used in both directions and at both ends of the perimeter. Of course, it is possible to bend by turning in the other direction, but no such turning or change of direction is required when pages 92 and 93 are made, as shown.

A series of side openings or holes 94 form the input path to the wire end 77 or 78. The wire end 77 or 78 is placed in the hole 94 and then moved along the piece 72 or 73 until it stops by gripping one side - $ 2 or 9 3. When inserted, the wire 76 presses the page 92 (or 93) by compressive force, but when it grips the end of the distal side 93 (or 92), it can move further. Thus, precise positioning is ensured and this can be done by automatically forming the desired tangential points of the wires 76 with each other and with the side pieces 74 and 75 of the circumference 71. When the wire end 77 or 78 is inserted, it cannot be pulled out, because when i is pulled out, the depressed side 9 2 (or 93) digs into the wire 7G and prevents outward movement. The purpose is to prevent any relative movement between the wire end 77 or 73 and the piece 72 or 73 after assembly. The wire 76 can be moved across the depressed side 92 by the container stop side 93, but cannot be moved against the side 92 after it has been inserted. As shown in Figures 7-10, the movement can occur in either direction with exactly the same effect; it can, of course, happen in opposite directions weeping. ···: ti ·· .ϊϊ 22 61 397 at opposite ends of the perimeter 71. Thus, the wires 76 are locked to the finished frame by friction in this form of the invention. The plastic coating 79 is covered after this combination is completed.

Fixing the circumference and spring wires by resistance welding (Figures 11-13)

Figures 11-13 show the use of a circumferential end piece 95 which is inverted channel or U-shaped and has resistance welded bosses 96 against which the wire ends 77 or 75 are moved. An inlet hole 97 is used for the wire 76. Various stopping devices may be used or the stop may simply be formed by a machine that inserts a spring wire 76 through a hole 97 in the inverted channel-shaped body 95. In any case, when the spring wire end 77 is inserted, it is temporarily held in place by resistance welding. is performed so that the thickenings 96 actually become the spring wire 76 and the spring wire 76 becomes part of the channel 95, keeping the circumference and the wire together as one piece. Resistance welds can be done one at a time or they can be done all at once for the entire end piece 95 or for both ends at once.

In this form of the invention, the assembly 70 is held together not only by the plastic coating 79, but also by welding at both ends. The plastic coating 79 is, of course, made after welding.

Latch mounting (Figures 14 and 15)

The structure shown in Figures 14 and 15 uses a latch-type friction fastening. In this case, the circumferential body 100 has a spring-like structure made in the shape of a channel with spring lips 101 and 102 which are closer to each other than the thickness of the wires 76. Although typically made of metal, the body 100 may be made of plastic. The lips 101 and 102 are spread apart as the spring wire 76 is inserted from the lower end by the side slot 103. After the wire end 77 is inserted, it is snapped into place and cannot be retracted because it is retained by the circumferential lips 101 and 102. Stops can be made with small holes or protrusions that restrict the passage of the wire end 77, or this may be completely unnecessary due to the use of holes or openings 103 that prevent unrestricted movement of the wire 76, which opening 103 is just large enough to insert the spring wire end 77. 100. Again 23 61397 the combination is then embedded in plastic 79.

Second friction lock and attachment of the unit to the nozzle frame (Figures 16-20) _______________

Figure 16 shows how a tubular circumferential end piece 105 of metal or plastic is formed to provide a series of holes 106 that receive the ends 77 or 73 of each spring wire 7G. The tube 105 is formed approximately opposite and longitudinally apart from the holes 106 to provide sides 107 and at the same time stops 108 which restrict the movement of the spring wire ends 77 within the tubular body 105. The inner portion 109 of the tube may fit snugly around the wire end 77 and there may be no kit retention device other than this. Fig. 17 shows that the tube 105 forms a tight friction fit with the wire end 77 so that the friction prevents the wire end 77 from moving back and forth and the wire end! 77 grips the end 108 of the next page 107, preventing further movement and acting as a stop. The plastic coating 79 also prevents relative movement between the tube 105 and the wire 76. If desired, some aids can be used, such as welding.

The tubular end piece 105 of Figure 16 is also shown to have hanging lugs 110 with an opening 111 through which suitable screws 112 or bolts or rivets can pass to secure the unit 70 to the chair frame piece 65, 66, 67 or 68. For example, as shown in Figures 10 and 18 , the screw 112 can simply pass through the lug 110 into the opening 113 in the tubular metal frame body 67.

Fig. 19 shows another way in which the same circumferential piece 105 can be used. In this case, the tubular metal chair frame piece lli + t is provided with upper openings 115 which receive the whole, the lug 110, and the screw 112 is inserted through this piece. and through the opening 111 in the side 110, holding them in place.

A similar method is shown in Fig. 20, in which the same frame piece 105 is used with the wooden frame piece 117 of the chair as the screw 112 passes through the wood into the opening 111. Of course, a different line c S · can be used.

2 „61397 and other fastening methods.

Combined type perimeter with friction lock (Figures 21-24)

Another way of attaching the spring wires 76 to the circumference 72 is shown in Figures 21-2 * +. These show a flattened duct-shaped circumferential end piece 120 of metal or plastic with an upper flat portion 121 and a lower flat portion 122. Friction retains the wire end 78 in place by a side 123 partially pierced out and bent up from the lower part 122. The wire end 73 is also held against the stop 12 * 4 in the circumferential end piece 120. Thus, both a friction retaining side 123 and a stop 124 are formed by a series of partially perforated outwardly bent pieces having a stop portion 124 deeper than page 123. The effect is shown in Figs. 22 to 24, Fig. 22 showing a final position in which the wire end 78 passes over the retention page 123 and cannot return. Fig. 23 shows the first insertion and Fig. 24 shows the compression and flattening of the side piece 123 as the wire end 73 passes over it, resulting in the locking of Fig. 22.

Figure 21 also shows a modified shape of the circumferential side body 125. The circumferential body 125 is not straight, like the side bodies 74 and 75, but a curved meandering body. In this case, its shape is different from that of the yarns 76, being substantially a blue curve that fills a large portion of the cavities in the yarn 76 that would otherwise be unfilled; therefore, although the meandering circumferential body 125 does not expose the large protrusions that would be present in the absence of the body 125. In contrast, the protrusions on display are relatively short and do not tend to stick to clothing. All this is again coated with plastic 79.

Fig. 20 also shows a meandering wire 126 having a length and shape different from other wires 76. The purpose of the wire 126 is to form a body having vibration characteristics different from those of the wires 76, 76a, etc. The purpose of this is to dampen bounces, a feature that is usually found to be necessary in a transport seat. The wires 76, 76a, etc., which typically have a single oscillation frequency, are attached in combination to a wire 126 having a different oscillation frequency and thus have been heavily modified and even eliminated from the pop-up properties of the combination 70.

Second circumferential shape and attachment shape to the spring body (Figures 25--27)

On the perimeter, the shapes present are virtually limitless.

Fig. 25 shows a corner portion of the circumference 130, where the second side piece 131 is integral with the end piece portion 132, which can define the end circumference of the entire circumference. A second piece of the same metallic wire type is shown at reference 133 parallel to the piece 132 but spaced apart along both side pieces 131. The pieces 132 and 133 are held together by resistance welding at reference point 139 to a third circumferential end portion 134. The circumferential end portion 134 has two flat portions 135 and 136 132 and 133, and between these flat portions is an open-ended tubular portion 137 that receives the wire end 78 through a series of openings 138. The pieces 78 are inserted through the openings 138 into the interior of the part 137 and pressed into the stop 139.

The assembly, which is held together by the resilience of the pieces, is then embedded in the elastomer 79. After embedding, the assembly may be slid into a hollow frame body 140, which may be an integral part of the chair or seat frame and has a continuous slot 141 through which the wires 76 pass. It should be noted that the yarns 76c, etc. are larger than the yarns 76a and 76b. This makes it possible to use heavier yarns at points with the highest seat pressure and lighter yarns at the front edge where overly stiff yarns can be uncomfortable. This myift dampens bounces because wires with different oscillation frequencies are next to each other in combination.

A subcombination of this combination with a circular perimeter (Figure 28)

Although usually the most desirable is a rectangular type perimeter, such as perimeter 71, this is not always the case. It can be made in the shape of a trapezoid or in another shape. Figure 28 shows a combination 143 as an example of what can be done. The assembly 143 has a circular, i.e., substantially circular, circumference 144 that is continuous and secured, e.g., by welding, to a series of spring members 76, etc. After attachment, the assembly is embedded in an elastomer or plastic to form finished compounds 143. The plastic 79 again joins the spring wire pieces 76 together and further helps to forcibly secure them to the circumference 61 397 2b 144 and to surround it, although the attachment is sufficient without it. The secure method of attachment is by direct welding, in this case, by any suitable type of welding, spot welding, spot welding or any other means. Although the perimeter 144 is circular, it should not be considered a flat perimeter.

It is again made in the same generally cylindrical shape as where unit 70 is shown in Figure 2, but the assembly 143 is extended outward and somewhat flattened, but not completely, in Figure 28 to show what it looks like when mounted on a chair frame but should be understood and remembered. that the whole combination is again a cylindrical segment, the ends of which almost meet before flattening.

Circumferential combination according to the invention (Figure 29)

Fig. 29 shows a combination 145 according to the invention without any circumferential body. The wire pieces 75, 76a, 76b ... 76n are also fastened together near their ends, but in this case not in them, with a series of resistance welded joints 146, 146a .... 146n. This attachment is made at only one point on each end. This use of a metal weld, which joins the wires together, in this case at two points, close to each end but some distance from it, is again a firm fastening. Since all the pieces 76, 76a, etc. have the same arcuate curve, they easily remain a unit in the general shape shown in Fig. 2, with Fig. 29 showing the assembly 145 flattened to the shape in which it would be in the finished seat.

In this case, the wires 76, 76a, 76b ..... 76n have free ends 77 and 78 which can be mounted on fasteners made in the frame of the chair itself, or pieces which press these into the frame of the chair can be used, or other fastening methods can be used. After welding, the assembly is completely embedded in plastic to provide a coating 79 of wires 76 and to provide bonds between the various wires.

It will be seen that in this case a series of welds 146, 146a .... 146n and the wires 76, 76a .... 76n in fact essentially form a perimeter, which in this case is a special perimeter in that ar * .ίϊ 27 6 1 3 9 7 it is made of a series of wire segments 76, 76a, etc. that are in line with each other and the weld joints 146. However, the unit 145 is a combination before it is mounted on the chair frame. It can be shipped in combination and is held together by a very strong metallic custom as well as plastic 79.

Combination welded to straight circumference C Fig. 30)

Fig. 30 shows a subassembly 150 in which the wires 75, 76a 75b, etc. are welded to a circumference 152 having side portions 153 directly to the end portion. The welds are located at 154, 154a, 154b .... The ends of the wire: 78 are shown outside the circumferential body 151 herein and may be used for fastening or may be cut off if desired and subsequently fastened by the circumferential portion 151.

It is intended that the same cylindrical shape of the unit 150 be understood, as in the previous drawings, as the assembly 150 is again a substantially cylindrical segment that must be flattened outwardly when mounted on the chair frame. The entire assembly 150 is coated with plastic 179 after welding is complete.

Another combination form in which the springs are welded to the circumference (Fig. 31)

The combination 155 shown in Figure 31 has a perimeter 156 which is shown to have an end portion 157 and a side portion 158. The perimeter 156 may be continuous. The compartment 157 is provided with a series of protruding portions 158 to which the wire ends 78 are welded at the joints 159 by any suitable weld method. The perimeter 151 comprises a welded structure and after the assembly is welded, it is again coated with plastic 79.

Modified chair shape (Figures 32 and 33)

Fig. 32 shows a chair 160 comprising a seat assembly 160 and a backrest assembly 162. The backrest assembly 162 is substantially similar to the combination 70A with two exceptions. First, the frame pieces 163 and 164 to which it is attached run horizontally rather than vertically; another exception is that the assembly 162 has circumferential end pieces 165 and 166, and these naturally run horizontally so that they can be attached to the frame.

'! -Vi 28 61 397 to paragraphs 163 and 164, but in this particular case, by way of example, there are no circumferential side pieces corresponding to paragraphs 74 and 75 of the combination 70 in Figure 2. Instead, the yarns 76 are free on both sides. Because they are on the sides of the chair, they are less likely to stick to clothing and can be left in their original condition. In this context, however, it is intended to cover them with a cloth 167 so that they are not really exposed and do not pose such a great danger.

The seat piece 161 is basically similar to the piece 162 for the back, but there is an important difference. The similarities are that the wires are free on each side, but the seat is covered with a fabric and has end pieces 170 and 171 attached to the chair frame pieces 168 and 164. The difference is that a bend 172 is used, which is a sharp bend apart peripheralLa 171 but relatively close to it. This bend 172 works to (1) give the chair a longitudinal seat pattern that is clearly different from the lateral pattern of the chair shown in Figure 1 and whose flexibility at the front is highly desirable, and (2) it also forms a highlighted curve at the front edge that makes the chair more comfortable than if it weren't.

Second longitudinal seating arrangement of the chair (Figures 34-36)

Fig. 34 shows a chair 175 with a seat combination 176 and a backrest combination 162, as in chair 160. The difference between the seat combination 176 and the seat combination 161 is that the seat unit 176 has a so-called "fish size structure" with two folds 177 and 178 in the front. next to the edge 179. The rear circumferential piece 170 is the same as the chair 160. The fish-sized structure provides more flexibility and comfort and is considered desirable by the manufacturers.

Fig. 36 shows how the peripheral pieces 170 and 160 can be attached to one horizontal frame piece 164 by a holder 180 which receives both of these pieces and has a pair of lugs 181 and 182 attached to the peripheral piece 164 by a screw 183 extending through the opening in the frame piece 164. through and through the opening 185 in the lugs 181 and 182, which lugs are approximately at right angles to the screw 183. It is also shown in the previous drawing, except that both the seat 176 and the back 162 are attached at the same time. , both of which are horizontal instead of vertical.

Compound Curve chair (Figures 37 and 38)

Figures 37 and 38 show chair 190. This chair utilizes the same combinations 70 and 70A that have already been considered as a seat and backrest. The difference in this chair is that the frame is constructed so that a combined curve is formed in the back and seat. Thus, the front legs 191 and 192 become side members 193 and 194 of the frame through relatively wide-radius bend portions 195 and 196, and the rear body 197 and 198 also have upper portions 199 and 199a that are curved. As a result, when the seat assembly "70" is installed, it has a front that is curved in the direction of the chair frame, while at the same time it curves between the frame pieces 193 and 194 and the same is true for the spine. The remaining curves increase comfort due to a more suitable contour. the front edge of the chair suddenly become legs and are likely to be uncomfortable and the curved part enhances this part and eliminates a sharp point of change insofar as this affects the occupant.

Principles of the invention folding chair (Figures 40-42)

Figures 40 and 41 show a folding chair 200 with a seat 201 and a back 202, which may be made of units 70 and 70A, which embodiments illustrate the principles of the invention. The folding chair 200 has a pair of frame side members 203 that support the seat 201, a pair of rear legs 204 that extend to the front of the chair 200, and a pair of front legs and back frame pieces 205 that support the chair 202.

Figures 40 and 42 show a significant feature of the invention. The seat 201 is curved upward and the back 202 is curved backward so that when the chairs 200 are folded, the seat 201 can fit inside the seat 202, as shown in Figure 41. This makes it possible to fold the chair 200 very tightly so that the thickness of the chair 200 in the formation space of such folding chairs does not have to be greater than the thickness of the frame.

The feature of this tight stackability can also be applied to a non-folding but tightly stackable chair (cf. U.S. Patent 26,701), where the seats lie tightly on top of the seats and the backs press tightly against the backs.

Some features of the folding chair portion are also illustrated in the schematic representation of Figure M-2. It can be seen in the figure that the seat 201 may have a smaller curvature than the back 202 and in most examples this forms a more comfortable chair 200 than if their curvature had been made solely for the purpose of fitting together. The concavity of the backrest should be equal to or greater than that of the seat, i.e., the radius of curvature of the seat 201 is greater than the radius of curvature of the backrest 202. The backrest 202 may be varied so that its radius is equal to the radius of the seat 201, or its radius may be up to half the radius of the seat 201 to provide both comfort and sufficient folding ability. Of course, when the curves are different, the stacking may be somewhat less dense, but this is a disadvantage that must be weighed against the other disadvantage that the seats and back are uncomfortable when sitting. Figure 42 shows another unique feature of the invention. The legal height of the seat piece 201 is between 0.64 and 2.54 cm. When the seat 201 is folded into the back 202, its lower side 206 - as well as the upper surface 207 - fits inside the tendon 208 of the back 202.

It is recommended that the radius of curvature R3 of the backing 202 be smaller than the radius of curvature R4 of the arc loan 201. The recommended radius R3 is 27.9 to 38.1 cm and the recommended R4 is 83.8 to 222 cm at 43.2 cm spans.

Some of the various wire patterns that are possible in this invention (Figures 43-51) _ <__

A substantially unlimited number of yarn patterns are possible in this invention. The pattern shown so far with the wire 76 is a very good pattern, but it is not the only good that can be used. The patterns can be used due to their structural features, due to the convenience of manufacture or due to their shapes. Some of these aspects will be apparent from the selected shapes shown, and it will be seen from all of them that the wires, whether in a parallel pattern or in alternating patterns, contact each other at least once per ring; touching 31 613 9 7 may occur at the level of each other in the same plane, or it may occur at levels above each other, even though the unit is still substantially in the same plane. Fig. 43 shows a yarn 211 with a vinyl coating 212 and an adjacent yarn 213 with a vinyl coating 212 on it. The yarns 211 and 213 are bent in the same pattern but placed alternately so that one is turned 130 ° with respect to the other; instead of each wire 211 being exactly parallel to its adjacent wire 213, their meanders are in opposite directions and an alternating effect is obtained. Alternation can provide some interesting design ways, as outlined here. The length of one ring is marked on the drawing, and it is seen that the ring is quite long partly due to the alternation and partly due to the wire pattern itself. Thus, the wire 211 starting at the left end has a long vertical portion 214, followed by a light-straight portion 215 followed by a short vertical portion 216, followed by a horizontal portion 217, preferably the same length as the portion 215. The portion 217 is followed by a portion 218, which is equal in length to the part 216 and which then leads to a second part 219, which is parallel to the part 215 and in the same line with it and which is again the same length. Section 219 is followed by section 220, which is longer than sections 216 and 218, the length of which is equal to section 214, thereby elevating the wire 211 to a new level. This is followed by a horizontal part 221 of the same length as the part 215 and parallel to it but separate from it. This in turn is followed by a short section 222 of the same length as the section 218, but starting at a different point, so that the next section 223 is not in the same line with the sections 215 and 219. The second part 2 24 is as long as the part 22 2 and is followed by the part 225 in the same straight line as the part 221 of the same length, and in turn is followed by a part 214a identical to the part 214 and starts a new ring.

The pattern of the yarn 213 adjacent to the yarn 211 is the same but opposite so that the yarns 211 and 213 contact the portions 215 and 219. The yarns 211 and 213 contact the other yarns adjacent to them in the portions 221 and 225. hThe contact portions in this case extend over the plastic coating 212 covers these parts as well as the individual yarns.

Fig. 44 shows a yarn 230 with a meandering shape and an adjacent identical yarn 231, both of which are covered with plastic 232. In this case, the length of one ring 32 61 3 97 is much shorter. The wire 230 has an upwardly extending portion illustrated by two nearly circular portions 233 and 2 · + with displaced radii, and these make-up circular portions 233 and 234 are joined together by a smooth curve 235. The pattern is again interesting and the structural effects are essentially the same as already has been described.

Fig. 45 shows a yarn 240 made in a similar meandering pattern to a yarn 76. Adjacent yarns overlap such that the yarn 240 is on top of the yarn 241 and the yarns 242 are below, and the plastic coating 243 connects all the yarns. This pattern forms a small opening 244 through the overhanging portions and a large opening 245. This forms an interesting pattern and is another way to form a combination and shows that the wires do not actually have to touch each other or be in an identical plane.

Fig. 46 shows a wire 250 and its adjacent wire 251 and a plastic coating 252. The figure shows another type of square wave pattern, which is different, and again the length of the ring is indicated.

Fig. 47 shows another form of the figure. In this case, the wire 255 actually passes over itself, forming successive circles such that no wire is actually in one plane, although the configuration is, of course, substantially planar. Successive wires touch each other.

Fig. 48 shows a square wave configuration formed by wires 260, 261, etc. and a plastic coating 262 with steps moving up and down.

Figures 49 and 50 show the angular configuration and two different uses of the same yarn 265 and coating 266. In Fig. 49, adjacent wires run opposite each other to form large spaces between them, while in Fig. 50, successive wires are parallel, forming trapezoids that are alternately turned upside down (in each row). The impressions are different but they use the same yarns. It should also be noted that auxiliary yarn 267 is used in Figure 50; this wire 267 has a different length and shape and thus has a different oscillation frequency 33 6 1 3 9 7 than the wires 265 and thus dampens bounces.

Fig. 51 shows overlapping yarns 270, 271 covered by a coating 272 that secures the yarns 270 and 271 together, with the second yarn 270 passing under the adjacent yarn 271, which in turn passes under its adjacent yarn 273, and so on.

fools are just examples of what can be done. Countless other patterns are possible.

Some other embodiments

Fig. 52 shows the lower part of a chair 280 in which the combination 70 acts as a seat, but which is turned upside down with respect to Fig. 1. This structure is perfectly usable, although not generally recommended. This is a simple straight-through shape; i. seat 70 is concave instead of convex.

Fig. 53 shows a stool 285, legs cut off, with a stool seat made by a combination 70 mounted to form a double arc, a concave arc, which is bent into an upper or convex arc as seen from the side. This seat 70 was mounted on the periphery of the stool 285 in the same manner as illustrated in Figure 37.

The thinness of the seats and backs of this invention is particularly important. Thus, the thickness of the coated wire - which is the thickness of the seat or back - should be between 1/200 and 1/50 of the length of the cylindrical arc of the combination 70, i. the length which will be the span of the seat or back.

Many changes in the structure as well as very different embodiments and applications of the invention will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The resuscitations and description provided herein are purely illustrative and are not intended to be limiting in any way.

M! s .S 5

Claims (11)

A seat or backrest portion (70) of a seat, comprising a plurality of arcuately tortuous or tortuous metal spring spokes (76), each having two ends, all approaching the adjacent wire at frequent intervals, and a thin sheath-like plastic cover ( 79) which surrounds said wires and which follows the winding or twisting of the wires and connects the wires at points where they pass close to each other so that the cover forms bridges between the wires, characterized in that the spring wires and the cover are formed as a separate seat, or as a backrest piece with fastening members (72, 73, 76, 77, 78, 95, 100, 105, 120, 140, 144, 151, 180) at their mounting edges as a unit to be mounted on the frame of the chair, which is in the shape of a cylindrical arc (R 1) and which has a curvature before mounting (R2) corrects somewhat when the unit is mounted on the chair frame, wherein the straightening causes the spring wires (76) to tension along a lowered cylindrical arc. A seat or backrest part of a seat according to claim 1, characterized in that the fastening edges of the unit have fixed fastening members (72, 73, etc.) surrounded by said sheath-like cover (79), which fastening members firmly grip the spring wires (76) near their ends and prevent movement of the yarns relative to the fastening members. A seat or backrest part of a seat according to claim 2, characterized in that said fastening members comprise a pair of parallel, straight end circumferential end pieces (72, 73) of the unit and means (e.g. 92, 93) for fastening them to the spring wires (76). ends. A seat or backrest part of a seat according to claim 3, characterized in that said fastening members consist of friction locks (92, 93, 94) which fasten both ends of each spring wire to said end circumferential end piece (72, 73) and prevent their retraction. 35 6 13 9 7 A seat or backrest part of a seat according to claim 3, characterized in that said fastening members consist of a plurality of welds (96), each of which welds a spring wire (76) near its end to said metallic peripheral end piece (95). A seat or backrest part of a seat according to claim 3, characterized in that said fastening members consist of tightly fitting tubular bodies (100, 105, 120) as said end circumferential end pieces, and spring members (101, 102, or 107 or 123) for locking the end of the spring wire thereon. in. 6-: 3 97 34 A seat or backrest part of a seat according to claim 1, characterized in that the value of the Shore A durometer of the cover (79) is between 45 and 90. A seat or backrest part of a seat according to claim 7, characterized in that the Shore A durometer of said cover (79) has a value of about 75. A seat or backrest portion of a seat according to claim 1, characterized in that the thickness of said cover (79) is about 1/5 of the thickness of the wire - about the thickness of the wire. A seat or backrest part of a seat according to claim 1, characterized in that the force required to pull the ends of the unit apart to mount it in the chair frame is 1.5 to 30 kN. Seat or backrest part of a seat according to one of the preceding claims, characterized in that the seat part is compressed by 2.5 to 7.6 cm when a person weighing 68 kg is sitting on it. 36 61 397