Cellular chair construction

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CELLULAR CHAIR CONSTRUCTION

FIELD OF INVENTION

The present invention relates to chairs and seating normally associated with but not limited to residential or commercial office work. These chairs and seating employ a number of methods of to enhance the user's comfort and promote ergonomically healthy sitting. These methods include various forms of padding and flexing of the seat and back as well as separate mechanical controls that control the overall movement of the seat and back.

BACKGROUND OF THE INVENTION

Various approaches to making a chair’s seat and back form fitting for various users are known in the industries of seating manufacture. These approaches range from the rather traditional use of contouring synthetic foam, to seat/back shells that have a degree of flex. There have also been approaches that use a frame that has a membrane or sling stretched or supported within said frame. Several problems exist with each of these approaches.

In the case of simply using foam padding, under normal manufacturing conditions it is difficult if not impossible to properly vary the amount of firmness and thus support from one area of a cushion to another. Additionally, having to use foam can lead to excessive heat-build-up between the seating surface and the occupant. One of the problems with foam is the forming /molding of it. Current manufacturing technology makes it a relatively inefficient process compared with the manufacture of the other components that make up a chair of seating surface. The forming/molding of a contoured seating surface is so slow that the manufacturer is forced to make many

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WO 03/061434 PCT/US02/00024 sets of molds (which usually are hand filled) in order to maintain the production pace. This is contrasted by a part or component that is made for the same piece of furniture yet it can be produced on a single injection-molding machine with a single mold and keep pace. Another problem inherent to the use of foam is that in order to achieve a finished look the cushions must be upholstered. When a manufacturer is forced to upholster a cushion a number of problem issues arise. Usually the formed or molded foam has curves, many of which can be compound-curves, which leads a manufacturer to use glue or other adhesives to make the fabric conform to the contours. This laminating technique often makes the foams surface firmer than it was when it was originally molded/formed because the glue/adhesive and the fabric are now part of the foam structure. Additionally, the amount of change can vary from fabric to fabric which results in an unpredictability of the firmness of a cushion from one manufactured unit to the next. If a slipcover is used, it must be sized properly. Such sizing can be difficult as a result of the differing mechanical properties found from one fabric to another. The most important properties of a fabric when upholstering a contoured surface are its thickness and its rate of stretch. Thickness variations can make one fabric upholster smooth around radii or contours, while a thicker one will wrinkle in the same area. Variations in the amount of stretch can lead to other problems. And so a proper size slipcover in one type of fabric, with its stretch characteristics, can be the wrong size in another type or style of fabric. Often a manufacturer will “wrap” a piece of fabric around a cushion and then staple the fabric to the underside/backside of the cushion. This approach also suffers from the aforementioned problems associated with using variable fabrics. Additionally, The manufacturer must now cover the staples and the area of the cushion not covered by fabric in order to achieve a finished look. This leads to an additional molding etc. that often also has to be upholstered.

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The other reality of cushion upholstery, regardless of the techniques used, is that whether it is done in a small shop or in a production situation, it is consistently the most labor -intensive aspect of chair/seating construction.

In the case of incorporating flex into the shells of a chair, no geometry to date has achieved the proper amount of flex in the right areas to give correct ergonomic comfort for a wide range of individuals. In the case of a sling approach, the curves imparted on the sling by the frame are simple in nature (non-compound) and thus cannot provide the proper contouring necessary for ergonomic comfort. Also, this approach leads to “hammocking”. Hammocking is when the sling is pressed in one area; the areas immediately adjacent have the tendency of folding inward, squeezing the occupant, again not yielding the proper ergonomic curvatures. An additional problem with sling chairs is that if the manufacturer makes the supporting sling surface taut enough to properly support a large-heavy person, the tension on the sling will be too great for a smaller person, resulting in discomfort.

Finally, the present state of the art dictates that the contours a designer may choose in seating design be generic in nature to accommodate the widest range of the population possible. In .an effort to increase comfort, manufacturers have produced “sized” (i.e. small, medium and large) chairs that effectively narrow the amount of contouring-compromise that the designer must normally exercise. Unfortunately, this leads to the manufacturer having to tool three independent products instead of one, and the manufacturers, wholesalers, and retailers having to stock (in this example) three times the quantity of product. Additionally, the end user is stuck with a chair that at some point in the future may be the wrong size. This invention addresses these shortcomings with a new and novel approach to seating construction.

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SUMMARY OF THE INVENTION

The present invention relates to an improved method of constructing seating surfaces, which provides greater comfort through superior surface adjustment for a variety of users. This invention is based on the principle of molding in a predefined contour that has biased, resilient, flexibility and thus memory. Additionally, the amount of flexibility or biasing may be customized within a seating surface, allowing “controlled-contoured displacement”. This allows the designer/manufacturer to precisely control and alter all aspects of the deflection of the seating surface from area to area simply and controllably. The seating surface construction is comprised of a plurality of support sections, or bosses/platforms and of a plurality of web connectors interconnecting the support sections. In some embodiments, the platforms are raised or at a plane that is closer to the occupant. In some embodiments, the construction also includes holes, or areas lacking material. As a result of this unique construction, the bosses or raised areas act to stimulate the skin and musculature of the occupant. Additionally, because the geometry can include selected contact areas (bosses/platforms), and areas with no material or otherwise out of contact with the occupant (holes), the invention also provides greater airflow to the occupant’s body and thus greatly reduces undesirable heat build-up. The support sections or bosses/platforms are more rigid than their corresponding web connectors.

A variety of methods are disclosed for making the bosses/platforms exhibit a greater degree of rigidity than the web connectors. One such method disclosed is to alter the thickness of the bosses/platforms versus the web connectors. And another method is to provide the bosses/platforms with stiffening geometry that provides a greater degree of rigidity than the web connectors. One such stiffening geometry could be the addition of one or more returns or ribs. Another such stiffening geometry could be to make the bosses/platforms out of a different material than the web connectors.

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Yet another such stiffening geometry could be to construct the webs with a geometry that acts as a hinge. Yet another stiffening geometry could be to make the given geometry out of a material that can exhibit stretch in addition to flexure. Additionally, the seating surface is more efficient and economical to produce.

So, an object of the present invention is to provide a new and improved method of chair seat and back pan construction, which provides greater comfort through superior resilient, flexible surface adjustment for a variety of users. A further object of the invention is to provide a new and improved method of chair seat back pan construction, which provides greater airflow to the contact areas of the occupant's body and optionally may also act to stimulate the skin and musculature of the occupant. A further object of the invention is to provide a new and improved method of chair seat back pan construction, which is more efficient and economical to produce.

According to a first broad aspect, the invention provides for a seating structure comprising: a plurality of boss structures spaced apart and arranged in a grid-like pattern defined by rows of the boss structures extending in a first direction and columns of the boss structures extending in a second direction, in which the first and second directions are substantially perpendicular; a plurality of first web structures joining adjacent pairs of the boss structures within each of the rows of the grid-like pattern, in which at least some of the first web structures are non-planar; and a plurality of second web structures joining adjacent pairs of the boss structures within the columns of the grid-like pattern; in which the first web structures in adjacent rows of the grid-like pattern are spaced apart and the second web structures in adjacent columns of the grid-like pattern are spaced apart, such that the spaced apart first and second web structures define openings therebetween.

In some embodiments of the invention the first and second web structures are thinner in section than the boss structures.

In some embodiments of the invention the boss structures comprise a first portion defining a seating surface and at least one rib extending from the first portion

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5a in a direction away from said seating surface.

In some embodiments of the invention the first and second web structures are made of an elastomeric material.

In some embodiments of the invention the first and second web structures are made of a first material and the boss structures are made of a second material, in which the second material is different than the first material.

In some embodiments of the invention the first and second web structures comprise a urethane material.

In some embodiments of the invention at least some of the first and second web structures are connected to a frame.

In some embodiments of the invention at least some of the second web structures are non-planar.

In some embodiments of the invention the at least some of the first and second web structures are V-shaped.

In some embodiments of the invention each of the boss structures has a body-facing surface, in which the body-facing surfaces of the plurality of the boss structures define a support surface.

In some embodiments of the invention at least some of the boss structures have a substantially circular cross-section when viewed from a direction substantially perpendicular to the support surface.

In some embodiments of the invention the first and second web structures are spaced apart from the support surface with the support surface being more proximal to an occupant than the first and second web structures when the occupant is supported by the seating structure.

Some embodiments of the invention further provide for a covering disposed over the support surface.

In some embodiments of the invention the support surface is exposed to an occupant.

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5b

In some embodiments of the invention the boss structures each have a thickness defined between a top and a bottom thereof, in which the first and second web structures are joined to the bottoms of the boss structures at a plurality of junctures, and in which at least some of the first and second web structures have a hinge apex spaced from the junctures of the bottoms of the boss structures and the first and second web structures.

Some embodiments of the invention provide for a chair comprising the seating structure of the first broad aspect of the invention.

In some embodiments of the invention the seating structure defines at least in part a backrest. In some embodiments of the invention the seating structure defines at least in part a seat.

According to a second broad aspect, the invention provides for a seating structure comprising: a plurality of boss structures arranged in a pattern; a plurality of web structures joining adjacent boss structures within the pattern, in which at least some of the web structures are non-planar, and in which the boss structures and the web structures are integrally formed as a unitary structure; and in which each of the boss structures has a body-facing surface, in which the web structures are spaced apart from the body-facing surface, with the body-facing surface being more proximal to an occupant than the web structures when the occupant is supported by the seating structure, in which at least some adjacent non-planar web structures defining the plurality of web structures are spaced apart such that the spaced apart adjacent non-planar web structures define openings therebetween and between the adjacent boss structures, and in which the openings have a non-planar periphery defined at least in part by edge portions of the adjacent non-planar web structures.

In some embodiments of the invention the plurality of boss structures and the plurality of web structures define at least in part one of a seat and back, and in which the pattern comprises rows and columns of the boss structures extending in substantially perpendicular directions respectively.

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5c

In some embodiments of the invention each of the boss structures has a body-facing surface, in which the body-facing surfaces of at least some of the plurality of boss structures are substantially circular.

In some embodiments of the invention the web structures are thinner in section than the boss structures.

According to a third broad aspect, the invention provides for a seating structure comprising: a plurality of boss structures arranged in a pattern; a plurality of web structures joining adjacent boss structures within the pattern, in which at least some of the web structures are non-planar; and in which each of the boss structures has a body-facing surface, in which the web structures are spaced apart from the body-facing surface, with the body-facing surface being more proximal to an occupant than the web structures when the occupant is supported by the seating structure, in which at least some adjacent non-planar web structures defining the plurality of web structures are spaced apart such that the spaced apart adjacent non-planar web structures define openings therebetween and between the adjacent boss structures, and in which the openings have a non-planar periphery defined at least in part by edge portions of the adjacent non-planar web structures, and in which the boss structures comprise a first portion defining a body-facing support surface and at least one rib extending from the first portion in a direction away from support surface.

In some embodiments of the invention at least some of the boss structures are connected to a frame. In some embodiments of the invention at least some of the web structures are connected to a frame.

According to a fourth broad aspect, the invention provides for a seating structure comprising: a plurality of boss structures arranged in a pattern; a plurality of web structures joining adjacent boss structures within the pattern, in which at least some of the web structures are non-planar; and in which each of the boss structures has a body-facing surface, in which the web structures are spaced apart from the body-facing surface, with the body-facing surface being more proximal to an occupant than the web

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5d structures when the occupant is supported by the seating structure, in which at least some adjacent non-planar web structures defining the plurality of web structures are spaced apart such that the spaced apart adjacent non-planar web structures define openings therebetween and between the adjacent boss structures, and in which the openings have a non-planar periphery defined at least in part by edge portions of the adjacent non-planar web structures, and in which at least some of the web structures are V-shaped.

In some embodiments of the invention the spaced apart adjacent web structures define substantially non-circular openings therebetween and between the adjacent boss structures when viewed in a direction substantially perpendicular to the support surface.

In some embodiments of the invention the non-circular openings are substantially hexagonal. In some embodiments of the invention the non-circular openings are substantially rectangular. In some embodiments of the invention the non-circular openings are substantially square. In some embodiments of the invention the non-circular openings are substantially octagonal.

In some embodiments of the invention the boss structures and the web structures are integrally formed as a unitary structure.

According to a fifth broad aspect the invention provides for a seating structure comprising: a plurality of boss structures arranged in a pattern; a plurality of web structures joining adjacent boss structures within the pattern, in which at least some of the web structures are non-planar; and in which at least some adjacent web structures defining the plurality of web structures are spaced apart such that the spaced apart adjacent web structures define openings therebetween and between the adjacent boss structures, in which at least some of the web structures are V-shaped, with an apex of each of the V-shaped web structures located at a proximate mid-point between the adjacent boss structures joined by the V-shaped web structures.

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5e

BRIEF DESCRIPTION OF DRAWINGS

FIGURE 1 is top view of the chair showing and its support frame with its seatpan seating surface removed.

FIGURE 2 is a side elevation of the chair according to a first embodiment.

FIGURE 3 is an isolated front elevation of the back resilient seating surface.

FIGURE 4 is an isolated front elevation of the resilient seat-pan seating 10 surface.

FIGURE 5 is an isolated top plan view of the back seating surface and seat-pan seating surface of Figures three and four.

FIGURE 6 is an isolated side elevation of the back seating surface of Figure 3.

FIGURE 7 is a top plan view of the seat-pan frame and the backrest frame that 15 is capable of receiving the seating surfaces of Figures 3 through 6.

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FIGURE 8 is a front elevation of the seat-pan frame and the backrest frame that is capable of receiving the seating surfaces of Figures 3 through 6.

FIGURE 9 is a side elevation of the seat-pan frame and the backrest frame, which is capable of receiving the seating surfaces of, Figures 3 through 6.

FIGURE 10 is a top plan view of the seat-pan frame and the backrest frame with the resilient seating surfaces of Figures 3 through 6 affixed in place.

FIGURE 11 is a front elevation of the seat-pan frame and the backrest frame with the resilient seating surfaces of Figures 3 through 6 affixed in place.

FIGURE 12 is a side elevation of the seat-pan frame and the backrest frame with the resilient seating surfaces of Figures 3 through 6 affixed in place.

FIGURE 13 is a perspective detail view showing configured webs that are both V-shaped in cross-section and W-shaped in cross-section.

FIGURE 14 is a perspective detail view showing configured webs that have a V-shaped cross-section.

FIGURE 15 is a plan detail view of the webbing structure.

FIGURE 16 is a detail anoxemetric view of Figure 15, showing one form the web may assume.

FIGURE 17 is a detail anoxemetric view much like Figure 16, except a single structural relationship is depicted, showing another form the web may assume.

FIGURE 18 is a detail anoxemetric view much like Figure 16, showing several bosses linked together by webs.

FIGURE 19 is a detail anoxemetric view much like Figure 18, except a larger field of structural relationships is depicted.

FIGURE 20 is a side sectional view taken along cutting line A-A of Figure 19.

FIGURE 21 is a side sectional view taken along cutting line B-B of Figure 19.

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List of reference numerals used in the Figures.

2—Seat frame

4—Back frame

6—Resilient seat surface or seat surface insert

8— Resilient back surface or back surface insert

10—Mounting groove of 2

12—Mounting groove of 4

14—Arm support structure

16—Arm pads

18—Web connectors of 6/8

20—Thickened support sections, or bosses/platforms of 6/8

22—Openings of 6/8

24-Zone of greatest flexibility

DETAILED DESCRIPTION OF THE INVENTION

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications and equivalents within the spirit and scope of the invention.

Referring to Figure 1, a top view of the seat-pan seating surface and its support frame can be seen. By referring to Figures 3-6, the shells or pans can be seen separate from the frames, and the frames can be seen separate from the seating surface shells or pans in Figures 1,2,7,8, and 9. Also, it should be noted that a separate peripheral support frame is not a necessity of the invention, for the shells could be selfsupporting with an integral structure. Additionally for clarification, a seat-pan, or back-pan seating surface refers to a structure which may be the primary surface, as in a plastic or wood chair, or a structure which may accept foam and upholstery and thus

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WO 03/061434 PCT/US02/00024 not be the primary surface as can be commonly found in many articles of furniture. Often these structures are also referred to as seating shells. All of these and any other terms used to describe a similar structure are considered to be equivalents and should be viewed as such.

Now referring to Figures 3, 4, and 16 the illustrated embodiment of a seating surface is comprised of a plurality of webs 18, thicker sections, or bosses/platforms 20, and openings 22. It is through the various geometric combinations of the three of these basic elements that improved seating comfort is achieved. This is why I also refer to the matrix as being “cellular” in nature, for it is a matrix of individual, independently acting cell structures. One embodiment optionally can have all three of these structures formed economically from one type of material and process such as plastic and molding. Any of the common molding methods known could be used including, but not limited to, injection, blow, or roto-molding. Additionally, through the use of advanced plastic injection molding techniques known to those in the industry as “two-shot” injection molding and “co-injection” molding, these elements may be selectively made from two or more types of materials to further control the overall engineering attributes of the structure. Additionally, this structure could be realized through other manufacturing techniques such as lamination, stamping, punching etc.

Referring again to Figure 16, a closer view of some of the matrix, it can be seen that the webs 18, function as thinner or more flexible interconnecting elements to the thicker or more rigid bosses/platform sections 20. It is through these webs that flexure occurs, allowing movement of one thicker or more rigid section relative another thicker section. Depending upon the final geometry selected this movement may have several degrees of freedom. For example, if the web is of the form as in detail Figure 16, where the web is predominantly flat in form, the web may act as a torsional flexure (occurring predominantly across the web’s width) for the thicker or

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WO 03/061434 PCT/US02/00024 more rigid bosses/platform sections.. Additionally, depending on the characteristics of the materials used, the web may stretch in length, allowing another form (linear flexure) of displacement. If, however, the web is of the form found in detail Figure 14,where the web is formed as a V, or an inverted V, the web may exhibit the preceding characteristics as well as act as a hinge, allowing the angle formed by the faces of the V to change. This would result in a different set of degrees of freedom of one boss/platform section relative to another.

Figure 13 shows a configuration predominantly the same as Figure 14. Of note is the fact that the web may also take the form of a W or inverted W, which could further increase flexibility. Also of note is the fact that the webs could be varied, in some areas or directions V’s could be used while in other areas or directions W’s could be used. Figure 13 shows W’s running vertically and V’s running horizontally in the example section. In addition to V’s and W’s other forms are envisioned, and so a number of varied geometric possibilities exist for the web geometry as well as the bosses/platforms and holes.

All of the aforementioned forms of webs, and other contemplated designs, all may share common types of flexure of varying degrees. It should be noted that the terms “thinner” and “thicker” sections are interchangeable with the terms “sections having greater” or “sections having less” flexibility relative to each other. Crosssectional area or thickness is but one way of varying the relative rigidity of the webs vs. the bosses/platforms. Another way is to provide the bosses/platforms with rigidizing returns, ribs or walls, so that structurally the bosses/platforms are stiffer than the joining webs.

Additionally, as stated earlier, the materials selected can play an important role in the performance of the geometry. For example, if the material selected is an elastomeric material, such as a urethane, the webs 18 could each stretch or elongate a small amount resulting in or allowing deflection or displacement of the thicker or

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WO 03/061434 PCT/US02/00024 more rigid bosses/platform sections 20. Another flexible material under consideration is Hytrel® polyester elastomers by Dupont. By each area responding individually the entire seating surface may emulate a soft cushioning effect to the occupant. As also mentioned earlier, it is possible, as through advanced molding techniques or fabrication, to use more than one type of molded material in a finished product. One such technique is to mold a part in one material in one mold and then place the part into another mold that has additional cavity area, and then fill that mold with another type of material. So it may be advantageous to for example to mold all the webs and connective areas in one material in one mold, and then to transfer the part to another mold to form all the thicker or more rigid bosses/platform sections and other features in another material.

Because webs join the platforms, holes or other types of areas lacking material positioned to contact the occupant (such as recessed portions) can be created which allow airflow and thus reduce the amount of heat build-up on the seating surface. These holes, or areas with no material or recessed material, further serve to allow the desired movement of the webs and the thicker sections. As shown, the holes are octagons, but any shape found suitable could be used.

It can also be seen that in some embodiments, the platforms are raised or at a plane that is closer to the occupant than the webs. This can improve aeration (via recesses defined by the tops of the webs), allow the bosses or raised areas act to stimulate the skin and musculature of the occupant, or both. As shown the top faces of the platforms or more ridged areas are predominantly flat, but this does not necessarily have to be the case. On the contrary, many stimulating/aerating surface shapes are contemplated. One such shape is a domed platform. Also contemplated is that the stimulating/aerating surface shapes may vary in both shape and intensity (depth of the raised area) from one area of the seating surface to another to maximize comfort and/or stimulation.

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Figure 17 is a detail anoxemetric view much like Figure 16, except a single structural relationship is depicted, showing another form the web structure may assume. The difference of this form of web structure can be appreciated by referring to Figures 18, 19, 20, and 21. Rather than the bosses/platforms being thicker in crosssectional than the web connecting members, the bosses/platforms are provided with structural returns or the reinforcing ribs mentioned previously. Thus functionally, the bosses/platforms will have a greater structural rigidity relative to their interconnecting web members. Figure 20 which is a sectional view taken along cutting line A-A of Figure 19 and Figure 21 which is a sectional view taken along cutting line B-B of Figure 19, show that the bosses/platforms have reinforcing returns that make the bosses/platforms more rigid than the connecting web structure. As shown the return wall on the bosses/platforms forms a ring. This is not a necessity though, the returns could be as simple as a single rib or more complex, having as many returns as are needed.

A critical aspect of this invention is the ability of the designer/manufacturer to precisely control and alter all aspects of the deflection of the seating surface from area to area simply and controllably. When a designer/manufacturer specifies a foam density (firmness/softness) for a cushion, the entire cushion is compromised by that unifying density. That is not the case with this invention, though.

Biomapping is data created through the comparison of body contours of a given population, or the data created through the comparison of contact forces exerted between a seating surface and the occupant. Although exercises in generating data have been ongoing for several years, the designer has still been limited to selecting generic contours, and then hoping that the foam will resolve the final fitting issues. This invention, however, makes it possible to effectively use the data generated by biomapping to precisely control the geometry (web-connectors, bosses/platforms, and

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PCT/US02/00024 openings) and thus the engineering properties area by area over the entire seating surface, so that each sector-area is functionally optimized.

It should be appreciated that by varying the size and shape of the holes or recesses, the location of holes, the types of webs and their relative thickness or geometry and the size, contour and relative thickness of the thicker sections or their geometry, a designer can custom design each area of a seating surface to perform as desired.

Figure 3 shows how the seating surface could be divided into zones; the area 24 indicates one such zone. This could be the zone of greatest flexibility. It should also be appreciated the advantage this offers the designer to economically manufacture an item from a material such as plastic, as well as the increased comfort that the user will experience.

Referring to Figures 7-9, both the seating frame 2 and the back frame 4 can be seen. These frames are substantially more rigid than the seating surface. These frames provide a support structure for the seating surface, and serve to connect the seating surface to the rest of the chair. In one contemplated embodiment the seating surface is carried within a seating frame by way of mounting grooves 10 and 12. It should be appreciated that the seating surfaces and the frames could be formed or manufactured as a single unit; however, several advantages may be realized if they are separate. One such advantage is that they may be made of different materials. In this way, each of the materials selected for their respective part may be optimized functionally.

Another advantage is that the way in which the two members, the seating surface and its frame, are attached may be variable. Techniques of manufacture and assembly could be used which would allow movement between the seating surface and its frame. This would give .yet more degrees of movement and cushioning to the occupant. One such attachment is a bridge defined by at least one resilient element connecting the seating surface and the support of other frame along the perimeter of

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WO 03/061434 PCT/US02/00024 ¹³the seating surface. The bridge can vary in rigidity along the perimeter so that the seating surface and the support cooperate to define a biased, selectively flexible seating surface.

An example of an attachment or bridge is a rubber mount that may take the form of a series of intermediate mounting pads, which occur between the seating surface and its frame. Similarly, the rubber or resilient material could take the form of a gasket placed between the seat surface and frame. Another way that such movement could be achieved is to produce a groove integral to the seating surface that would follow the same path as the mounting groove. Such a groove could be pleated like the web found in Figure 14, and thus would allow a degree of lateral movement. Another method would be to have the seating surface snap into place using tabs and slots that had enough free-play relative to each other to yield desirable results. Either the seating surface or the frame could have the slots and the other the tab members.

Yet another method would be to configure the two elements so that one or the other had standing legs formed predominantly perpendicular to the other element. In this way, when the two are assembled, and allowed to shift relative to each other, the legs would flex. This, like the rubber or resilient mounts, would allow biased relative movement that would not feel loose. These tabs or the functionality of them could be combined with the snap tabs. As a matter of fact, any of the attachment methods could be successfully combined. Additionally, any of these attachment techniques could be implemented using mounting grooves such as 10 and 12, by surface mounting the seating surface directly on the surface of the seat/back frames. It is also contemplated that the entire assembly (frames, resilient seating surface inserts, and flex gasketing material) could be manufactured using the advanced multi-material •25 molding techniques (two-shot, co-inj ection) previously mentioned. This would have the potential advantages of increased economy, ease of manufacture, and increased structural integrity.

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Another critical feature of the invention, in regard to the way in which the seating surfaces interact with the seating frame, concerns sizing. As previously mentioned, it is a handicap to the designer to try to design a chair with the proper contours for the full range of the population. The resulting designs and contours are necessarily compromises, and thus are not optimal for any given individual. As also previously mentioned, in an effort to overcome these limitations, manufacturers have produced “sized” (i.e. small, medium and large) chairs that effectively narrow the amount of contouring-compromise that the designer must normally exercise.

There are several aspects to sizing. The first is the overall sizing of the surfaces as far as width, height etc. As far as comfort is concerned, this is the least important aspect of seating surface design. Appropriately sized seating surfaces can be formulated that satisfy the extremes. A more important aspect in achieving seating comfort is the contouring of the seating surface. Unfortunately, this contouring varies greatly from a small individual to a large one. Additionally, some individuals who seemingly share the same body types prefer differing contours such as stronger/weaker lumbar contours. Although the present invention addresses this need for variable contouring through its innovative flexure structure, further advantages in comfort can be realized if the initial contours of the seating structure are in the proper range for the occupant. Through the present invention’s unique method of construction, these goals are all achievable.

As previously outlined, the seating surfaces can be attached to the seating frame by a variety of methods. The manufacturer can produce one basic chair frame or a small set of such frames, and then into the same set of one or more frames insert many different contoured seating surfaces. Obviously, this has the advantage of eliminating the need of the manufacturer having to tool three independent products instead of one. It also has additional advantages. Because the seating surfaces are so easily attached and detached from their frames, it is conducive to a fieldCA 02472222 2004-06-25

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PCT/US02/00024 customization scenario. In this way, wholesalers, and retailers could stock frames, and then have a variety of seating surfaces in various contours and colors. This would allow the retailer to customize the product on the spot for the customer. Additionally, the end user is not stuck with a chair that at some point in the future may be the wrong 5 size. The size/color scheme can be updated at any point of the product’s life by simply obtaining a fresh set of seating surfaces. Thus, a new and improved method of chair seat and back pan construction, which provides greater comfort through superior surface adjustment for a variety of users, has been provided.

Also provided is a new and improved method of chair seat back pan construction that provides greater airflow to contact areas of the occupant’s body.

Also provided is a new and improved method of chair seat back pan construction that is more efficient and economical to produce.