CA2586759C

CA2586759C - Flexible furniture system

Info

Publication number: CA2586759C
Application number: CA2586759A
Authority: CA
Inventors: Todd P. Macallen; Stephanie J. Forsythe
Original assignee: Molo Design Ltd
Current assignee: Molo Design Ltd
Priority date: 2007-05-01
Filing date: 2007-05-01
Publication date: 2015-02-17
Anticipated expiration: 2027-05-01
Also published as: CA2586759A1

Abstract

An article of flexible furniture having a core formed from a plurality of laminar panels of a flaccid material and each panel having a pair of oppositely directed major faces, adjacent faces of said panels being inter-connected to provide a cellular structure upon movement of abutting faces away from each other, a pair of supports at opposite ends of said core and connected to respective ones of said faces, said supports being self-supporting to provide rigidity to said core whereby said supports may be moved apart to expand said cellular and extend the length of said partition.

Description

4 [0001] The present invention relates to flexible furniture components and methods of making such components.

7 [00021 Furniture is a staple product used in domestic, working and public environments.
8 Furniture may be used to facilitate the use of space, such as in a seat or table, or to divide space, 9 such as in a partition. By way of example, partitions are frequently used to subdivide spaces, or to create more intimate spaces. Typically such partitions are rigid, or have rigid frames, or are 11 formed from rigid interconnected panels and they are relatively large, heavy, and cumbersome, 12 and therefore difficult to set-up, take down, store, and transport.
Similarly other items of 13 furniture, such as seating structures, are typically of a rigid, or permanent nature that, at most, are 14 moveable to alternative locations.
[00031 Moreover, the inherent rigidity of such items of furniture limits the extent to which 16 they can be dynamically resized (extended or contracted) and reshaped to suit varying spaces and 17 requirements, or readily moved around for relocation, or storage.
18 100041 Additionally, such furniture items, particularly in the form of partitions are typically 19 formed from opaque panels which inhibit the transmission of light, therefore necessitating increased use of, or rearrangement of artificial lighting to restore adequate lighting levels.
21 100051 In domestic, working, and public environments it is frequently desirable to be able to 22 subdivide and reshape space on a temporary basis. For example, visitors may require a 23 temporary sitting or sleeping area, office workers may need to convert an open plan area into 24 subdivided working space or temporary meeting space, trade show participants may need to demarcate a temporary display area, and designers may need to create and shape a temporary 26 area for an event, or a backdrop for a designed area, such as in a window display in a retail 27 setting, in a showroom, or in a theatrical setting. For these types of applications, furniture -22505254.1 1 components that are rigid, heavy, and/or cumbersome may be costly to transport, difficult to set 2 up/take down, and may require significant storage space. Furniture in the form of a partition that 3 is rigid will also place significant constraints on the ways in which a given space can be 4 partitioned, limiting its functionality, and a partition that is fully opaque will severely disturb natural lighting.
6 [0006] It is therefore an object of the present invention to provide articles of furniture in 7 which the above disadvantages are obviated or mitigated.

9 100071 According therefore to one aspect of the present invention there is provided an article of furniture having a core formed from a plurality of laminar panels of a flexible flaccid material.
11 Each panel has a pair of oppositely-directed major faces with faces of adjacent panels being 12 inter-connected to provide a cellular structure upon movement of the faces away from each 13 other. A respective one of a pair of supports is provided at opposite ends of the core and 14 connected to respective ones of the faces. The supports are self-supporting to provide rigidity to the article of furniture and/or to provide connectivity between like articles of furniture. In this 16 way, the supports may be moved apart to expand the cellular structure and extend the overall 17 length of the article of furniture, and/or be used to connect any of more than one of such articles 18 together in series.

[0008] Embodiments of the invention will now be described by way of example only with 21 reference to the accompanying drawings in which:
22 100091 Figure 1 is a front perspective view of a partition;
23 [0010] Figure 2 is a perspective view showing three of the panels used to form the partition 24 of Figure 1;
[0011] Figure 3 is a view on the line of Figure 1;

22505254.1 1 [0012] Figure 4 is a series of views showing the sequential operations required to erect the 2 panel of Figure 1;
3 [0013] Figure 5 is a detailed view of the portion shown in circle A in Figure 4;
4 [0014] Figure 6 is a view showing the sequential steps to join a pair of panels shown in Figure 1 end-to-end;
6 [0015] Figure 7 is a detailed view of the inter-connection of the panels shown in Figure 6;
7 [0016] Figure 8 is a top perspective view showing the arrangement of a panel within a living 8 area;
9 [0017] Figure 9 is a top perspective view showing an alternative configuration of panel;
[0018] Figure 10 is a schematic representation of an alternative embodiment of connection 11 applied to a partition;
12 [0019] Figure 11 is a view on the line XI-XI of Figure 10;
13 [0020] Figure 12 is a view in the direction of arrow XII of Figure 11;
14 [0021] Figure 13 is a schematic diagram showing the arrangement of the connection of Figure 10 with different size partitions;
16 [0022] Figure 14 is a top perspective view of a seat arrangement incorporating the 17 connection of Figure 10;
18 [0023] Figure 15 is a view on the line XV-XV of Figure 14;
19 [0024] Figure 16 is a front elevation of a light incorporating a connection similar to Figure 10; and 21 100251 Figure 17 is a section on the line XVII-XVII of Figure 16.
-3..
22505254.1 2 100261 Referring therefore to Figure 1, a partition 10 comprises a core 12 and a pair of 3 supports 14, 16 at opposite ends of the core 12. As can best be seen from Figures 2 and 3, the 4 core 12 is formed from a plurality of panels 18. The panels 18 each have a pair of oppositely-directed major faces 19, 20, and are formed from a flexible flaccid material.
In the preferred 6 embodiment, the material forming the panels 18 is standard white, flame retardant tissue paper, 7 having a weight of approximately 13.5Ibs (500 sheets @ 24"x 36" =
13,5lbs). Each panel has a 8 major dimension or height h and a width w which may be adjusted to suit particular 9 environments. Typically the height will be in the order of 1-2 metres but could range from 0.5-3 metres when used as a partition, or 0.1 metres to 0.5 metres when used as a seat. A seat height of 11 0.45m has been found particularly beneficial. The width is typically in the order of 30 12 centimetres but could range from 10-100 centimetres. Adjacent panels 18 are inter-connected to 13 one another at spaced intervals that alternate across the width of the face of the panel 18. As 14 indicated in Figure 2, the connection between panels 18a and 18b is through a series of parallel, laterally-spaced strips 24 on the face 19 of panel 18b. The strips 24 are defined by stripes of 16 adhesive, which connects the panels 18a, 18b to one another, as shown in Figure 3.
17 100271 Similarly, the inter-connection between a panel 18b and 18c is through spaced 18 parallel strips 28 on the face 19 of panel 18c which are offset from the strips 24. Each of the 19 panels 18 is therefore alternately connected to the panel 18 on opposite sides so that, as shown in Figure 3, upon extension of the panel in a horizontal direction, a cellular structure having voids 21 30 is formed within the core. The voids 30 extend vertically from top to bottom of the core 12 22 with the panels 18 providing a continuous transverse barrier. The lateral outer ends of each of 23 the panels 18 are connected so as to form vertical pleats on the exterior faces of the core 12.
24 100281 An end panel 18d of the core is connected to respective ones of the supports 14 and 16 over its entire width. The supports 14 and 16 are made from a self-supporting material, 26 typically a non woven felt material, which has a degree of flexibility but also has sufficient 27 rigidity to resist collapse of the core 12. In a typical application, the felt is a 1.95 nominal 28 pounds per square yard felt having a thickness in the order of 3 millimetres, although other 4.
22505254.1 1 weights and thicknesses may be utilized as appropriate depending upon the overall dimensions of 2 the partition 10. The supports 14 and 16 extend laterally beyond the core as indicated at 32 and 3 are adhered to respective ones of the end panels 18d.
4 [0029] Fasteners in the form of a pair of loop and hook strips 34, such as that sold under the trade name "Velcro" are stitched to the felt supports 14 and 16, and extend vertically from one 6 end to the other.
7 [0030] The core 12 is collapsible so that the major faces of adjacent panels 18 lay parallel to 8 one another and in abutment. In this position, as shown in Figure 4a, the partition 10 may be 9 stored in a flat, collapsed position. When the partition 10 is required, it can be oriented vertically (figure 4b) and the opposite supports 14 and 16 used to manipulate the partition. The supports 11 14 and 16 are moved away from one another as shown in Figure 4c to expand the core so that the 12 cellular structure is opened within the core 12. The lateral extension of the supports 14, 16 13 beyond the core 12 provides marginal tabs that may be grasped to facilitate manipulation of the 14 core without direct contact with the panels 18.
[0031] Once partially extended, the supports 14 and 16 may be folded along a vertical axis to 16 provide enhanced rigidity at each end of the partition 12. This may be seen in more detail in 17 Figure 5 where it will be seen that the opposite edges of the supports 14 and 16 may be brought 18 together so that the loop and hook strips 34 are brought into abutment.
The loop and hook strips 19 34 engage one another and thus hold the support in a folded tubular configuration. This movement is accommodated by the flexible nature of the cellular structure which expands 21 towards the lateral edges to accommodate the folding of the supports 14 and 16. With the 22 supports 14 and 16 folded into a tubular support, extension of the core 12 continues as shown in 23 view (e) of Figure 4, until the desired overall length is reached.
24 [00321 With the partition 10 expanded, it has sufficient width to remain stable in a vertical position with the rigidity provided by the end supports 14 and 16. The material forming the 26 panels 18 is preferably translucent so that a pleasing transmission of light through the panel may 27 occur, while still providing a degree of privacy.

22505254.1 1 100331 The extended partition as shown in Figure 4e may be adjusted to different 2 configurations as illustrated by the open curve shown in Figure 1 and the wrapped curve shown 3 in Figure 8. The core 12 has a surprising degree of flexibility to accommodate different 4 configurations and allow an appropriate shaped and sized partition to be installed in an otherwise open space. By varying the overall dimensions, additional functionality may be obtained. The 6 extended partition shown in Figure 4e may also be made with a lower height, for example 1 7 metre and a wider base, for example 0.5 metres so that the top surface of the partition may be 8 used as an area to display objects. Such an arrangement is illustrated in Figure 9. Where 9 appropriate, the terminal portions of the voids 30 may be used as a pocket to support a container, such as a vase, or similar object. In this embodiment. the height would be between 0.5 and 1.5 11 metres.
12 100341 The provision of the supports 14 and 16 also permits a pair of partitions 10 to be 13 joined end-to-end as shown in Figure 6. As may be seen from Figure 6a, a pair of partitions 10 is 14 erected and positioned with supports 14, 16 at opposite ends of each partition adjacent one another. The loop and hook strips 34 in adjacent supports 14, 16 are then brought into contact 16 with one another as shown in Figure 7 so that the partitions 10 are joined in seriatim. The 17 additional thickness provided by the double support at the intersection enhances rigidity, with the 18 supports 14, 16, at the free ends of the partition being folded upon themselves to provide stable 19 support.
100351 After use of the partition 10, it is simply necessary to reverse the procedure by 21 moving the ends towards one another, unfolding the supports 14 and 16, and collapsing the core 22 12 to its minimum size. It may then be stored and used when subsequently required.
23 100361 In the above embodiments, the core has been made from a light weight paper 24 material, although it will be apparent that alternative materials may be used that fulfil the same functional requirements. For example, it is possible to utilize a heavier weight paper material, 26 such as Kraft paper. or a non-woven textile material such as a plastic material known as TyvekTM
27 from DuPont TM which is both tear and water resistant. Alternatively, a paper laminated with a 28 plastic film to provide a composite material may be used. With such a core material, the 22505254.1 1 supports 14 may be made of a felt or may be made from a material similar to the core material 2 but with increased thickness. The felt used in the support would be sufficiently flexible to allow 3 folding to define the tubular support structure at each end with fasteners such as the loop and 4 hook strips 34 incorporated on the support. In some applications, the inherent stiffness of the material used in the core is such as to provide sufficient rigidity to the core when the cellular 6 structure is expanded for the core to be self supporting when expanded.
Kraft paper or plastics 7 material has provided sufficient rigidity for this purpose. In this case the supports may be 8 provided to permit connectivity if multiple units are to be joined end to end.
9 100371 Whilst a translucent material is preferred, it will be apparent that opaque or different coloured materials may also be utilized, The dimensions of the void 30 and the number of voids 11 in the lateral direction may be adjusted to suit particular applications. It has been found in 12 practise that a spacing between stripes 24, 28 in the order of 5-10 centimetres (when 13 unexpanded) is appropriate, although spacing as low as lcm. may be used, and that the width of 14 the stripes 24, 28 is between 1 and 10 millimetres. This arrangement provides a flexible structure with extensive elongation to provide maximum functionality.
16 [00381 An alternative form of connection for articles of flexible furniture is shown in Figure 17 10 -12, in which like reference numerals will be used to denote like components with a prefix 1 18 added for clarity. In the embodiment of Figure 10, a pair of partitions 110 are arranged to be 19 joined end-to-end in a manner similar to that shown in Figure 6. The end panel 118d of the core 112 is secured to supports 114, 116. The supports 114, 116 are made from a self-supporting 21 material, which in this embodiment are preferably made from a rigid material such as a 22 millboard. The supports 114, 116 lay within the periphery of the end panel 118d so that the end 23 panels 118d overlap by a margin in the order of 20 millimetres around the millboard.
24 [00391 Each of the supports 114, 116 has a series of holes 140, best seen in figure 11 formed through the millboard. The holes are arranged in a regular pattern, as will be described more 26 fully below with respect to Figure 13, and are arranged to receive rare earth magnets 142. The 27 magnets 142 are typically in the order of 3 millimetres thick and 25 millimetres diameter. The 28 magnets are a tight sliding fit in the holes 140 so as to be frictionally retained by the millboard.

22505254.1 1 The millboard itself is chosen to be of the same thickness as the magnet 142 so that the face of 2 the magnet 142 is flush with the surface of the millboard.
3 [00401 The magnets 142 are oriented such that a common polarity is present for all magnets 4 on one face. Thus the magnets in the support 114 shown in Figure 10 are oriented such that the north pole is exposed and those of the support 116 in the adjacent partition 110 are arranged such 6 that a south pole is exposed. The exposed end face of the millboard is wrapped by a cover 144 7 of the same material as used to produce the core 112 for aesthetic purposes and to retain the 8 magnets in situ. The cover 144 extends over the edges and each face of the millboard to provide 9 self containd end supports 114, 116 to facilitate manufacture as well as enhance the aesthetics.
[0041] With the magnets in situ, the partitions 110 may be connected to one another by 11 relying upon the magnetic attraction between the opposite poles of adjacent partition. The rare 12 earth magnets 142 have sufficient force to retain the supports 114, 116 in abutment with one 13 another. However the supports may be readily separated by sliding the partitions relative to one 14 another or pulling them apart axially to release the magnets. The margin of the end panel 118d provides a flexible tab to permit manipulation of the core 112.
16 [00421 As can be seen in Figure 13, the arrangement of magnets 142 on the support 114, 116 17 provides a grid that allows different size partitions to be connected in seriatim. The magnets 142 18 are arranged in two columns in rows uniformly spaced such that a relatively tall partition may be 19 attached to a relatively small partition with the magnets 142 in alignment. The grid also allows partitions to be stacked on top of one another and connected in seriatim to a taller partition to 21 form a continuous wall.
22 [0043] Whilst it is convenient that the supports 114, 116 are formed from rigid millboard to 23 carry the magnets, it will also be apparent that a similar arrangement may be achieved using the 24 self-supporting flexible supports 114, 116 such as the felt shown in the embodiments of Figures 1 through 9. The end panel 118d and the covering panel 144 secures the magnets 142 within the 26 flexible support 114, 116 so as to be retained within the hole 140. This arrangement would also 27 allow the end panels to be folded as shown in Figure 5 provided that the orientation of the 22505254:1 I magnets is such that one column has a north polarity and the other column has a south polarity.
2 A complimentary arrangement on the support of an adjacent partition will still permit the 3 partitions to be joined to one another in seriatim as well as folded.
4 [00441 The embodiments are described above in the context of a partition. However, the ability to dimensionally resize the core 12 provides for its use in alternative articles of flexible 6 furniture, such as those shown in Figures 14 through 17. In the embodiment of Figure 14, a 7 circular seat 210 is provided having a concave upper surface 211. As seen in Figure 15, the 8 lower surface 213 of the core 212 is planar to sit against the floor and the upper and side surfaces 9 smoothly curved. The opposite end faces 218d of the core are secured to supports 214, 216 that carry a series of magnets 242. The magnets are wrapped by a cover 244 of the material used to 11 form the core to provide a pleasing aesthetic as well as secure the magnets 242 within the 12 supports 214, 216. The seat 210 may be stored in a collapsed flat position and when needed 13 expanded into a circular array with the supports 214,216 in abutment.
The magnets 242 secure 14 the supports 214, 216 to one another and hold the core 212 in the circular configuration presenting an upper concave surface 211. For storage, the supports are separated and the core 16 collapsed to a flat configuration.
17 100451 As shown in figure 14, the seat 210 is formed from three cores 212 joined end to end 18 to make a torus. It will be apparent that the overall diameter of the seat 210 may be increased by 19 expanding the inner diameter of the torus and thereby further expanding the cores 212.
Alternatively, a single core 212 may be used with the supports 214,216 connected to one another, 21 provided there are sufficient laminated panels to permit extension of the core over the required 22 circumference. In this case, the diameter will be similar to that shown in figure 14.
23 100461 A simple seat may be provided in a similar manner by having an expanded core 212 24 with a planar upper surface 211, arranged either in a cylindrical form with supports 214,216 in abutment, or in the form of a bench with said supports not in abutment. In each case, multiple 26 units may be joined end to end to increase the diameter of the cylindrical seat, or the length of 27 the bench, which can be arranged linearly, or in an undulating manner, and which can act as a 22505254.1 1 form of partition, as shown in figures 1 to 9, and may be stacked one on top of the other to 2 increase the overall height..
3 100471 When used in a seating embodiment, the dimensions of the cellular structure and the 4 stiffness of the material used is adjusted to provide an increased structural rigidity and increased weight bearing capacity. kraft paper has been found to have the requisite properties and it has 6 been found preferable to reduce the spacing between the glue stripes to 2.5 cm so that the 7 maximum dimension of each void 30 in a collapsed state is 5cm.
8 [0048] A similar arrangement of flexible furniture is used with respect to a light as shown in 9 Figures 16 and 17 in which like reference numerals will be used to denote like components with a prefix 3 for clarity. In the embodiments of Figures 16 and 17, a light 310 is formed with a core 11 312 with end panels 318d secured to respective supports 314, 316. In this arrangement the axis 12 of the voids is radial although an axial orientation may be used if preferred. The supports, as 13 shown in Figure 17, carry an array of magnets 342 so that the supports may be joined to one 14 another as described above. A bulb 350 is located within the centre chimney formed by the fanning of the core 312. The bulb 350 illuminates the core 312 to provide a pleasing effect and 16 the heat may escape through the central aperture provided by the core.
Naturally the core is 17 formed from a fire-resistant material, or the light source produces only a small amount of heat.
18 The light 310 may be collapsed and stored in a flat configuration and deployed as required in 19 different locations.
[0049] It will be apparent from the various embodiments described above that the provision 21 of the cellular structure to form the core and the releasable fastenings provided at the end panels 22 allow for a variety of configurations to be provided. The provision of the magnets or other 23 fasteners in a pre-defined grid permits different components to be joined to one another to 24 increase a variety of configurations that may be utilized. As indicated above, the dimensions of the core may be adjusted to suit particular requirements, ranging from a single row of voids to 26 provide a thin or narrow partition, to a relatively wide cellular structure with multiple rows of 27 voids to provide seating or table like surfaces.

22505254.1 1 [0050] Although the invention has been described with reference to certain specific 2 embodiments, various modifications thereof will be apparent to those skilled in the art without 3 departing from scope of the invention as outlined in the claims appended hereto.

22505254.1

Claims

What is claimed is:

1. A freestanding extensible wall for partitioning an area of a room, said wall having a base, a top, oppositely directed surfaces extending between said base and said top, said base, top and surfaces defining a core, said core formed from a plurality of laminar panels of a flaccid material and each panel having a pair of oppositely directed major faces extending from said base to said top, adjacent faces of said panels being inter-connected to provide a cellular structure having a void extending from said base to said top upon movement of abutting faces away from each other, a pair of supports at opposite ends of said core extending from said base to said top and connected to respective ones of said faces, said supports being self-supporting to provide rigidity to said core and cooperate with said core to maintain the vertical extent of said wall, whereby said supports may be moved apart to expand said cellular structure and extend the length of said core, whilst maintaining its vertical extent, and at least one magnetic fastener on each of said supports to permit connection to an adjacent support of another similar article.

2. The wall according to claim 1 wherein said supports are flexible so as to be foldable into a tubular configuration about an axis parallel to said major faces, and said magnetic fasteners on said supports are located to maintain said tubular structure.

3. The wall according to any one of claims 1 and 2 wherein said cellular structure defines a plurality of parallel voids oriented on the longitudinal cods of said panels.

4. The wall according to any one of claims 1 to 3 wherein said panels are formed from paper.

5. The wall according to any one of claims 1 to 3 wherein said panels are formed from a non-woven material.

6. The wall according to claim 5 wherein said non-woven material is a plastic.

7. The wall according to any one of claims 1 to 3 wherein said panels are formed from a composite material.

8. The wall according to claim 7 wherein said composite material includes a plastic and paper.

9. The wall according to claim 8 wherein said composite material is a paper laminated to a plastic film.

10. The wall according to any one of claims 1 to 3 wherein said supports are formed from a felt panel.

11. The wall according to any one of claims 1 to 3 wherein said supports are formed from a non-woven material.

12. The wall according to any one of claims 1 to 3 wherein said supports are formed from a rigid board.

13. The wall according to claim 12 wherein said board is wrapped by a covering.

14. The wall according to claim 13 wherein said panel extends laterally beyond said board.

15. The wall according to any one of claims 1 to 14 wherein said magnetic fasteners are embedded in said supports so as to be flush with a surface thereof.

16. The wall according to claim 15 wherein said surface of said supports is covered by a wrapping..

17. The wall according to any one of claims 1 to 16 wherein said magnetic fasteners are located at predefined locations to permit attachment of said support to a similar support of a different article.

18. The wall according to claim 17 wherein said magnetic fasteners are arranged on a grid.

19. The wall according to claim 18 wherein said magnetic fasteners are arranged at spaced intervals along a pair of parallel strips and aligned magnets on each of said strips have an opposite polarity.

20. The wall according to claim 19 wherein said magnets in each strip alternate in polarity.

21. The wall according to any one of claims 1 to 20 wherein said panels have a major dimension of between 0.1 and 3 meters.

22. The wall according to claim 21 wherein said panels have a major dimension of between 0.1 and 0.5 metres.

23. The wall according to claim 21 wherein said panels have a major dimension of between 0.5 and 3 metres.

24. The wall according to any one of claims 1 to 23 wherein said panels have a width of between 10 and 100 centimetres.

25. The wall according to claim 24 wherein said width of between 30 and 45 centimetres.

26. An assembly of walls. each constructed according to claim 1, wherein said walls are arranged in seriatim with a support of one wall adjacent to and in abutment with a support of another wall, and magnetic fasteners releasably securing said supports to one another.

27. An article of flexible furniture having a core formed from a plurality of laminar panels or a flaccid material and each panel having a pair of oppositely directed major faces, adjacent faces of said panels being inter-connected to provide a cellular structure upon movement of abutting faces away from each other, said panels being formed from a material having sufficient rigidity to provide rigidity to said core when said core is expanded into a cellular structure upon extension of said core, a pair of supports located at opposite ends of said core and having a magnetic fastener secured thereto to permit connection to an adjacent support of another similar article, said magnetic fasteners being embedded in said supports so as to be flush with an outwardly directed surface thereof.

28. The article according to claim 27 wherein said cellular structure defines a plurality of parallel voids oriented on the longitudinal axis of said panels.

29 The article according to any one of claims 27 and 28 wherein said panels are formed from paper.

30. The article according to claim 29 wherein said paper is a kraft paper

31 The article according to any one of claims 27 and 28 wherein said panels are formed from a non-woven material.

32. The article according to claim 31wherein said non-woven material is a plastic,

33. The article according to any one of claims 27 to 32 wherein said supports are rigid.

34. The article according to any one of claims 27 to 32 wherein said supports are flexible.

35. The article according to any one of claims 27 to 34 wherein said core is expanded to define a torus to position said supports in abutment and with said magnetic fasteners securing said supports to one another.

36. The article according to claim 35 wherein one surface of said torus formed by said core is concave.

37. The wall according to claim 35 wherein said core is expanded to define a torus to position said supports in abutment and with said magnetic fasteners securing said supports to one another.

38. The article according to claim 37 wherein one surface of said torus formed by said core is concave.