NZ549392A - Method of expanding a sheet material and articles produced thereby - Google Patents

Abstract

A sheet material is provided with a plurality of slots within a region, the longer slots being near the centre of the region and getting shorter toward the outer perimeter of the region. The edges of the sheet are then pulled apart, in particular, a pulling force is applied in the plane of the sheet and perpendicular to the length of the slots which effects a distortion and curvature of the sheet and forms an expanded mesh in the area of the slotted region. Sheets of plastics and metal can be formed into expanded mesh shapes using the technique.

Description

NEW ZEALAND PATENTS ACT, 1953 I j 3 AUG 2007 | IreceiveB.

No: 549392 Date: 23 August 2006 COMPLETE SPECIFICATION METHOD OF EXPANDING A SHEET MATERIAL AND ARTICLES PRODUCED THEREBY We, VICTORIA LINK LIMITED, a New Zealand company, of 15 Mount Street, Kelburn, Wellington, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 11049(51-1 1 549392 2 FIELD OF THE INVENTION The present invention relates to a method of expanding a sheet material and articles produced thereby. In particular, but not exclusively, the present invention relates to a 5 method of expanding a two-dimensional metal sheet by laser-cutting an area of the metal sheet, and expanding the cut area to form a mesh.

It is known in the art of metal forming to expand sheets of metal. Referring to Figures 1A-1D, a conventional prior art method of metal expansion is shown. In Figure 1A, a two-dimensional metal sheet 10 is placed on a semi-guillotine expanding machine and is advanced between an upper knife 12 and a lower knife 14 of the machine. The upper knife 12 is then lowered to cut the sheet 10 before expanding the metal to form one half of a 15 diamond design, as shown in Figure IB. In Figure 1C, the upper knife 12 is repositioned by half a diamond length. Then, in Figure ID, the upper knife 12 is once again lowered to cut and expand sheet 10. By repeating this process, an expanded metal mesh is obtained.

It is also known in the art of metal expansion to make circular or concentric cuts in a 20 selected cut area of a metal sheet and to expand the sheet by pushing or pulling out the cut area in a direction perpendicular to the sheet. Such an expansion is illustrated in the online PingMag magazine website (http://www.pingmag.jp/2006/05/05/making-contemporary-furniture-with-japanese-simplicity/).

The Center Piece Model 1001XL bowl is illustrated on the Questo Design website (http://www.questodesign.com). That bowl does not have a mesh, and its configuration is such that a roller would need to be used to form the bowl into the desired shape.

In this specification, where reference has been made to patent specifications, other external 30 documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents or sources of information is not to be construed as BACKGROUND TO THE INVENTION 1520632-1 IN i'ELiJ~0TUAl P.i jPtFiTY Ci-HCli CI- N.Z. 3 0 2023 549392 3 an admission that such documents or sources of information in any jurisdiction are prior art, or form part of the common general knowledge in the art.

The object of the present invention is to provide a method of expanding a sheet material and articles that are either improved over prior art methods and articles, or that at least provide the public with a useful choice.

The term 'comprising' as used in this specification and claims means 'consisting at least in part of, that is to say when interpreting statements in this specification and claims which include that term, the features prefaced by that term in each statement all need to be present but other features can also be present. Related terms such as 'comprise' and 'comprised' are to be interpreted in a similar manner.

As used herein, the term 'mesh' when used in relation to an expanded cut area of a sheet material generally denotes the formation of a plurality of strands of the material interconnected at a plurality of bond areas.

In a first aspect, the present invention broadly consists in a method of expanding a sheet material, at least a portion of which is generally planar and encompasses first and second generally transverse directions, the method comprising the steps of: making a plurality of cuts through a cut area of the sheet material in said at least a portion of the sheet material, wherein the cuts have lengths; and applying a pulling force on the sheet material at least a component of which is transverse to the lengths of at least some of the cuts and at least a component of which is in a direction substantially parallel to at least one of the first and second generally transverse directions to expand the cut area; wherein prior to expansion, in a direction perpendicular to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and in a direction parallel to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer SUMMARY OF THE INVENTION 1520632-1 3fi psi'-i ^ /i,;3 549392 4 to the edge of the cut area, and wherein the plurality of cuts are arranged such that the cut area forms a mesh when expanded, and wherein at least part of the cut area curves about each of the first and second directions when the cut area is expanded.

Preferably, the step of making a plurality of cuts comprises making a plurality of rows of cuts, with each row comprising a plurality of cuts. Preferably, the cuts within one row are generally staggered with the cuts in an adjacent row, and the regions between cuts within each row form bond areas, such that the bond areas in one row are generally offset relative to the bond areas in the adjacent row.

Preferably, the step of making a plurality of cuts comprises making a plurality of linear cuts.

Preferably, the method comprises making the plurality of cuts with a laser cutter.

Preferably, the sheet material is sheet metal. Alternatively, the sheet material may be a sheet plastic. The sheet material may also be formed of other materials, including thick leather and the like.

Preferably, the curvature of the sheet material once expanded is non-uniform.

Preferably, the mesh comprises a plurality of primary strands and a plurality of secondary strands that differ from the primary strands, wherein the primary strands are connected to each other by secondary strands. A single secondary strand may connect adjacent primary strands. Alternatively, a plurality of secondary strands may connect adjacent primary 25 strands. The primary strands may connect to the secondary strands at primary bond areas, and the secondary strands may connect to each other at secondary bond areas.

Preferably, the primary strands deform to a lesser extent than the secondary strands when the cut area is expanded.

Preferably, the strands have a length and a width, with the width of the primary strands being greater than the width of the secondary strands. 1520632-1 r/UAi P.-O, ■■■' t ■70'.: < 3 C JL': 2i:3 r*r / r, i,:: \ fVED 549392 Preferably, the primary strands extend substantially the entire length of the mesh portion.

Preferably, the sheet material comprises material around the cut area, and the method comprises curving at least part of the material around the cut area as a result of expanding 5 the cut area to form the mesh.

Preferably, the plurality of cuts are arranged in rows, each of which has a length, with a longest row arranged generally in a centre of the cut area and with the length of the rows decreasing as they get closer to a point at which the pulling force is applied to the sheet 10 material.

Preferably, the pulling force is applied at points adjacent to and externally of the cut area.

Preferably, the pulling force is applied in a direction that is co-planar with the generally 15 planar portion of the sheet material.

Preferably, the method comprises forming a plurality of cuts in a plurality of discrete cut areas in the sheet material, and expanding those cut areas to form a plurality of discrete meshes. The discrete cut areas may be expanded concurrently. Alternatively, the discrete 20 cut areas may be expanded consecutively.

The method may be used to make a chair component. In another form, the method may be used to form any other suitable article.

In a second aspect, the present invention broadly consists in an article made by the method of the first aspect above.

In a third aspect, the present invention broadly consists in an article adapted to be expanded, the article comprising: a sheet material, at least a portion of which is generally planar and encompasses first and second generally transverse directions; and a plurality of cuts extending through a cut area of the sheet material in said at least a portion of the sheet material, wherein the cuts have lengths; 1520632-1 INTELL'TfUAL P.Vu^BYiY C.-HCc OF N.Z. 3 0 2C33 549392 6 wherein the cut area is adapted to expand to form a mesh when a pulling force is applied on the sheet material, with at least a component of the pulling force being in a direction transverse to the lengths of at least some of the cuts and at least a component of which is in a direction substantially parallel to at least one of the first and second generally 5 transverse directions, wherein in a direction perpendicular to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and in a direction parallel to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut 10 area, and wherein at least part of the cut area curves about each of the first and second directions when the cut area is expanded.

In a fourth aspect, the present invention broadly consists in an article comprising: an expanded sheet material, at least a portion of which is generally planar and 15 encompasses first and second generally transverse directions prior to being expanded; and a mesh portion on the sheet material, the mesh portion being defined by a plurality of cuts in a cut area that has been expanded, wherein the cut area is in said at least a portion of the material; wherein, prior to expansion, the cuts have lengths, and in a direction perpendicular 20 to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and in a direction parallel to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and wherein at least part of the 25 expanded cut area is curved about each of the first and second directions as a result of the cut area being expanded.

The following preferences are applicable to each of the third and fourth aspects above.

Preferably, the cut area, prior to expansion, comprises a plurality of rows of cuts, with each row comprising a plurality of cuts. Preferably, the cuts within one row are generally staggered with the cuts in an adjacent row, and the regions between cuts within each row 1520632-1 INiELLGOTUAL P30,-i£?,7> CiTICE GF Kt.Z. 0 n ft *\r "s.* Ob PECEfVPr. 549392 7 form bond areas, such that the bond areas in one row are generally offset relative to the bond areas in the adjacent row.

Preferably the cut area, prior to expansion, comprises a plurality of linear cuts.

The sheet material may be sheet metal. Alternatively, the sheet material may be sheet plastic. The sheet material may also be formed of other materials, including thick leather and the like.

Preferably, the curvature of the sheet material once expanded is non-uniform.

Preferably, the mesh comprises a plurality of primary strands and a plurality of secondary strands that differ from the primary strands, wherein the primary strands are connected to each other by secondary strands. A single secondary strand may connect adjacent primary 15 strands. Alternatively, a plurality of secondary strands may connect adjacent primary strands. Preferably, the primary strands connect to the secondary strands at primary bond areas, and the secondary strands connect to each other at secondary bond areas.

Preferably, the cuts are arranged such that the primary strands deform to a lesser extent 20 than the secondary strands when the cut area is expanded.

Preferably, the strands have a length and a width, with the width of the primary strands being greater than the width of the secondary strands.

Preferably, the primary strands extend substantially the entire length of the mesh portion.

Preferably, the sheet material comprises material around the cut area, and at least part of the material around the cut area is curved as a result of expanding the cut area to form the mesh.

Preferably, the plurality of cuts in the cut area are arranged in rows, each of which has a length, with a longest row arranged generally in a centre of the cut area and with the length INTELLECTUAL PA GrRCC G" te.2 3 8 £3 ***** ' ' "• • •/ Ipw- f 549392 8 of the rows decreasing as they get closer to a point at which the pulling force is applied to the sheet material.

Preferably, the article comprises a plurality of cuts in a plurality of discrete cut areas, each 5 of which expands to form a plurality of discrete meshes.

Preferably, the article is a chair component. In another form, the article is any other suitable article.

Where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individuaEy set forth.

The invention consists in the foregoing and also envisages constructions of which the 15 following gives examples only.

BRIEF DESCRIPTION OF THE FIGURES Preferred forms of the method and article of the present invention will now be described 20 with reference to the accompanying figures in which: Figures 1A-1D show a prior art metal expansion process; Figures 2A and 2B show a preferred form of the method of the invention; Figures 2C and 2D show preferred forms of the articles produced by the method of Figures 2A and 2B; Figures 3A and 3B show an upright chair component form of the article of the invention; Figures 4A and 4B show a lounge chair component form of the article of the invention; Figures 5A and 5B show the making of one form of mesh; Figures 6A to 6E show the making of other forms of mesh; Figure 7 shows an alternative chair component form of the article of the invention; and INTELLECTUAL PnOrtirfiY OFFICE OF N.Z. 3fj{ M y two PFr.Pi w p r> 549392 9 Figure 8 shows another alternative chair component form of the article of the invention.

DETAILED DESCRIPTION OF THE PREFERRED FORMS The Preferred Forms of the Method Referring to Figures 2A and 2B, one preferred form of the method of the invention is illustrated. The sheet material to be expanded is indicated generally as 20. At least a 10 portion of the sheet material is defined by a generally planar x-y plane encompassing first and second generally transverse directions, represented by the x-axis and y-axis illustrated. Although the sheet 20 shown in Figure 2A is entirely planar, skilled persons will appreciate that the sheet material 20 may include portions that are not planar. The sheet material 20 may be formed of a plastics material such as polystyrene or polypropylene, or metals such 15 as aluminium or steel, for example.

Where the article to be produced is required to have a structural quality, aluminium or stainless steel is the preferred sheet material. Aluminium has the potential to elongate further and requires less force to expand as compared to stainless steel. It also has the 20 advantage of a better weight-to-strength ratio compared to stainless steel. To lessen the chance of the article collapsing, however, stainless steel may be used instead of aluminium.

In Figure 2A, the sheet material 20 is provided with a plurality of cuts through a cut area 22 of the sheet material. The cuts may be linear cuts or curvilinear cuts. In the form shown, a 25 plurality of linear cuts have been made on the sheet material 20.

Preferably, the cuts are initially designed on or programmed numerically into a computer aided design (CAD) package or graphics package. A three-dimensional parametric modeling software package, SolidWorks, may be used, for example. Drawings produced 30 by the CAD package are preferably converted into appropriate code for use by a laser cutter 23 to make the plurality of cuts. Skilled persons will appreciate that the data transfer from CAD drawings to the laser cutter may be done by specialized converters. Laser cutting is, however, not essential to the present invention as the cuts may alternatively be 1520632-1 fiv nEa.Lr.Cfj.m. Pr.o.-'crffv Or ^Cc Or N.Z.

If! " I ">"*") J ^ • V lltarWV 549392 made using arrangements of knives or blades, such as those used in click-pressing processes, or by any other suitable process.

Referring to Figure 2B, once the cuts have been made, the sheet material 20 is subjected to 5 a pulling force at least a component of which is in a direction substantially parallel to at least one of the x and y axis of the sheet material 20 to expand the cut area 22. In the form illustrated, two equal and opposite forces 24 are applied to the sides of the sheet material 20 that are parallel to the cuts made. In other words, the forces 24 are applied perpendicular to the cut lengths. The two opposite sides of the sheet material can be 10 clamped and the clamps moved apart to achieve that pulling force. Skilled persons will appreciate that it is possible to clamp or fix the sheet material 20 on one side, and impart a pulling force only on the opposite side to expand the cut area 22. Alternatively, pulling holes may be arranged on the sheet material and a spreading tool may be used to engage the holes and impart the required pulling force. In the preferred form, pulling holes are 15 provided adjacent the cut area.

The force is termed a 'pulling force' as it results in expansion of the cut area to form the mesh. However, it will be appreciated that the apparatus that provides the expansion could engage two portions of the material and push them apart but still expand the cut area. 20 Such a valiant is encompassed by the 'pulling force' terminology.

As an example, the sheet material could be provided in a planar form, with holes provided adjacent either edge of the mesh. A scissor-type spreading tool could be used, with the tips of the scissor-type spreading tool engaged in the holes. As the scissor type tool is opened, 25 the tips will apply an outward pushing force to the holes, thereby pulling the mesh into an expanded configuration.

If desired, the sheet could be placed on a former and the pulling force applied, so that the former enhances the curvature that results from the mesh being expanded.

In one form, as a result of imparting a pulling force on the sheet material, the sheet material 20 expands at the cut area to form the article 26 in Figure 2C. In this form, the 1520632-1 INTELLECTUAL PKOr'cH'i 1 Gi:FiCE OF N.Z. 549392 11 expansion of the cut area in the article 26 forms a mesh 28, and results in the sheet material 20 curving about the x-axis and y-axis, indicated by arrows X and Y respectively.

The sheet material used for the present invention is suitably semi-rigid, so that it will hold 5 its shape to at least some extent following expansion of the cut area to form the mesh. The material may need to be connected to a frame or other type of support to maintain the desired shape.

The methods of the present invention form a mesh following expansion of the cut area. 10 The term 'mesh' when used in relation to an expanded cut area of a sheet material generally denotes the formation of a plurality of strands of the material interconnected at a plurality of bond areas. More particularly, a mesh has a plurality of strands of the material interconnected at a plurality of bond areas, one or more of which is intermediate the lengths of the strands. Preferably, there are a plurality of bond areas intermediate the 15 lengths of the strands. Preferably, adjacent strands are interconnected by at least three bond areas.

In the form shown in Figure 2D, as a result of imparting a pulling force on the sheet material, the sheet material 20 expands at the cut area to form a mesh 29. In this form, the 20 mesh 29 comprises primary strands PS and secondary strands SS, with the primary strands PS being connected to each other by secondary strands SS that differ from the primary strands. Additionally, the primary strands are connected by material at the edges of the mesh. Preferably, the secondary strands SS are bonded to each other at secondary bonds SB, while the primary strands PS are bonded to secondary strands SS at primary bonds PB. 25 The primary strands PS and secondary strands SS have a length and a width, with the width of the primary strands PS preferably being greater than the width of the secondary strands SS. Also, preferably, the primary strands PS extend substantially the entire width of the mesh. Preferably, the secondary strands also extend substantially the entire width of the mesh. Each secondary strand has secondary strand bridging portions SSBP between 30 adjacent bonds PB, SB.

As can be seen from Figures 2C and 2D, the primary strands PS deform to a lesser extent than the secondary strands SS in the width direction of the strands, as the material is INffc'L.. .jTUAL PaDi-'cfiTV Gi-FICc Or" N.Z. 3 9 XTA 223 i5.hjv;= D 549392 12 deformed. The ratio of deformation in the width direction of a primary strand PS relative to its length is less than the ratio of deformation in the width direction of a secondary strand bridge portion SSBP relative to its length.

The Preferred Forms of the Article In one form, the present article is an article adapted to be expanded in use. The article in this form is the sheet material 20 illustrated in Figure 2A. As before, the sheet material defines, at least in part, a generally planar x-y plane encompassing first and second generally 10 transverse directions, represented by an x-axis and a y-axis. The sheet material is provided with a plurality of cuts extending through a cut area of the sheet material in the generally planar part. In one aspect, the cut area is adapted to expand to form a mesh when a pulling force is applied on the sheet material, and where at least a portion of the force is in a direction substantially parallel to one or both of the x and y axes, with at least part of the 15 sheet material being curved about the x-axis and y-axis as a result of the cut area being expanded. In another aspect, the cuts in the cut area are arranged such that, when the cut area is expanded, the resulting mesh comprises primary strands PS and secondary strands SS as illustrated in Figure 2D.

It will be appreciated that the cuts need not be aligned with or parallel to the x-axis or y-axis. However, it is preferred, although not essential, that the pulling force is applied in a direction perpendicular to a length of at least some of the cuts. At least a component of the pulling force will be applied in a direction across (or transverse to) the length of at least some of the cuts.

The article in this form may be one part of a stow-away plastic or metal chair that a user assembles when required. The article may also be used as a precursor for other forms of article of the invention, as will be described below.

In another form, the article of the invention comprises an expanded sheet material, such as that shown in Figure 2C. Prior to being expanded, the sheet material defines, at least in part, a generally planar x-y plane having an x-axis and a y-axis. An example sheet material prior to being expanded is shown generally as 20 in Figure 2A. Once expanded, referring 1520632 1 549392 13 to Figure 2C, the sheet material includes a mesh portion 28, the mesh portion being defined by a plurality of cuts that have been expanded. In one aspect, as shown in Figure 2C, the expanded sheet material is curved about the x-axis and y-axis as a result of the sheet material being expanded, as represented by X and Y in the figure. As shown in Figure 2D, 5 the expanded sheet material may have a mesh portion 28 that comprises primary strands PS and secondary strands SS, with the primary strands PS being connected to each other by secondary strands SS.

Figure 3A shows a seating component 30 of an uptight chair as an example article of the 10 invention. The seating component 30 comprises a mesh portion 32 and curvature about the x-axis and y-axis, indicated with arrows X and Y respectively. The mesh portion 32 is shown in more detail in Figure 3B. The figure shows pulling holes 34 that are provided adjacent the mesh portion 32 to expand the mesh. In the figure, the centre holes 34a and 34b were used to expand the mesh portion 32. The seating component 30 in use would be 15 supported by a base or legs (not shown) to from the upright chair.

Figure 4A shows a seating component 40 of a lounge chair as another example article of the invention. The seating component 40 comprises a mesh portion 42 and curvature about both the x-axis and y-axis, indicated with arrows X and Y respectively. The mesh 20 portion 42, as shown in more detail in Figure 4B, includes primary strands PS and secondary strands SS, with the primary strands PS being connected to each other by secondary strands SS. The seating component 40 in use would be supported by a base or legs (not shown) to form the lounge chair.

In both the above designs, the seating component forms an integral seat and back of the chair.

The Preferred Forms of the Cuts As noted earlier, a plurality of cuts are made to the sheet material in a cut area that is later expanded to form a mesh. In a first form, the expansion of the cut area to form a mesh causes at least part of the sheet material to curve about the x-axis and y-axis. In a second form, the expansion of the cut area forms a mesh comprising primary strands and 1520632-1 549392 14 secondary strands that differ from the primary strands, with the primary strands being connected to each other by secondary strands.

Referring to Figure 5A, rows of cuts C, having row length RL and cut lengths CL, have 5 been made to a cut area on the sheet material 60. Each row has a plurality of cuts. When expanded, as shown in Figure 5B, the cut area forms a mesh having strands S with a strand width SW. The areas between the cuts C become bond areas B having a bond length BL.

The cuts within one row are generally staggered with the cuts in an adjacent row, such that 10 the bond areas in one row are generally offset relative to the bond areas in the adjacent row.

To create a mesh that causes at least part of the sheet material to curve about the x-axis and y-axis, the plurality of cuts may be arranged such that the cuts do not extend from one end 15 to another end of the sheet material. In other words, the cuts are internal, or contained by solid uncut sheet material. This is, however, not crucial in achieving the expanded sheet material of the present invention.

To create a mesh that comprises primary strands and secondary strands, with the primary 20 strands being connected to each other by secondary strands, an example and non-limiting pattern of cuts as shown in Figure 6A may be made. The pattern of cuts is such that, when expanded, as shown in Figure 6B, primary strands PS and secondary strands SS are created, with primary strands PS being connected to each other by secondary strands SS. It can be seen that the primary strands PS form continuous strips within the mesh. Skilled persons 25 will appreciate that patterns other than that shown in Figure 6A can be used to create primary and secondary strands as described above.

As another alternative, rather than providing a plurality of secondary strands (two are shown in Figure 6A by way of example) between each pair of primary strands, a single 30 secondary strand could be provided between each pair of primary strands. A suitable cut pattern is shown in Figure 6C. 1520632-1 C.-FIC!- O" t-i,Z. •r W e v H M.'CH •L? 549392 The number of secondary strands could vary across the mesh. For example, a single mesh could be provided with a plurality of secondary strands between at least one pair of primary strands, a single secondary strand between at least one pair of primary strands, and/or at least one pair of direcdy connected adjacent primary strands.

It was noted earlier that the cuts need not be internal or contained by solid uncut sheet material to curve about the x-axis and y-axis when expanded. An example of cuts that are not internal is shown in Figures 6D and 6E. As can be seen, the non-internal cuts have been expanded to form an article. Although the cuts in this form produce primary strands 10 and secondary strands, this is not essential. In this form, it can be seen that even though the primary strands and secondary strands have the same widths, the deformation in the width direction of a primary strand is less than the deformation in the width direction of a secondary strand.

The specific form of the expanded sheet material and the mesh can be varied by varying parameters relating to the plurality of cuts. The three main parameters that can be varied are: (i) the length of the row of cuts, RL (ii) the number of bonds B per row of cuts, and (iii) the ratio between the bond length BL and the cut length CL. For instance, the resulting mesh could be varied by cutting longer length cuts in the middle of the sheet 20 material and decreasing the length of cuts towards the outer edges. Alternatively or additionally, the bond areas of the mesh could be arranged such that longer bond areas are provided in the middle of the sheet material and bond areas decrease in size towards the outer edges.

The arrangement of the plurality of cuts may also be varied between rows of cuts on the sheet material. In particular, one or more rows of cuts may differ from one or more other rows of cuts in terms of: (i) the length of the row and (ii) the length of the cuts in the row. For instance, the cuts may be arranged in accordance with three preferred criteria — (i) the longest row of cuts is substantially in the centre of the cut area, with the length of the rows 30 decreasing as they get closer to each pulling point, (ii) in a direction perpendicular to the cuts, from one row to another, the longest cuts are in the centre of the cut area, with the length of cuts decreasing as they get closer to each pulling point, and (iii) in a direction parallel to the cuts, along a row, the longest cuts are substantially in the centre of the cut 1520632-1 r. RGi 0~ N.2. r, , * E! Q > Mr *1 l a L*4?" 549392 16 area, with the length of cuts decreasing as they get closer to edge of the cut area. It will be appreciated that these arrangements are preferred arrangements and the three criteria above are not essential to the present invention.

Other ways in which to vary the expansion of the sheet material include the amount of force used and the direction of the force used during expansion of the sheet material. For instance, instead of the direction shown in Figure 2B, the direction may be angled with respect to the planar portion of the sheet material so that a component of the force is parallel to the planar portion of the sheet material. Alternatively or additionally, instead of 10 expanding the mesh using the middle pair of holes (shown as 34a and 34b in Figure 3B), the sheet material may be expanded by pulling the cut area by engaging different combination of holes. If the holes at which the pulling force is applied is not the middle pair, the cut length and bond area graduation described above are preferably altered such that longer length cuts and bond areas are provided near the holes at which the pulling 15 force is applied. Further, the layout of the cuts may be such that the cuts are not aligned in a single direction. For instance, the cuts may be fanned out.

In another form of the invention, the sheet material could be provided with a plurality of discrete cut areas that each expand to form a mesh in the manner described above.

Figure 7 shows an alternative upright chair component as an example article of the invention. This component is similar to the article shown in Figure 3A and 3B. In addition to the cut area that expands to form a mesh portion 32, the component has an additional cut area 132 that is discrete from the first cut area. In the form shown, the 25 additional cut area is positioned generally in the lumbar region of a seated occupant, to provide a support for that region of the occupant's back, and again forms a mesh that curves around two axes. The mesh could be any of the types described above.

In this form, a pulling force is applied across the second cut area that causes the lumbar 30 region mesh to expand and curve rearwardly around a horizontal axis and about a generally vertical axis. 1520632-1 549392 17 Figure 8 shows an alternative chair component as an example article of the invention. This component is similar to the article shown in Figure 2C. In addition to the cut area that expands to form a mesh portion 28, the component has an additional cut area 128 spaced horizontally from the first cut area. This enables a chair component to be formed that 5 provides discrete support regions for multiple occupants. Again, this cut area 128 forms a mesh that curves around two axes. The mesh could be any of the types described above. The chair component could be provided with three or more discrete cut areas, each of which is configured to expand to form a mesh in accordance with the method of the invention. The discrete cut areas may be expanded concurrently to form respective 10 meshes. If the discrete cut areas are sufficiendy spaced apart and/or the connecting material is sufficiendy flexible, the cut areas may be expanded consecutively.

Two, three, or more cut areas could be provided in sheet material to provide articles with discrete meshes for desired purposes.

While the preferred forms of the present invention has been described with reference to chairs, skilled persons will appreciate that the present invention is not so limited. On a smaller scale, for example, the article of the present invention may be used in medical applications. For instance, the article may be used as a surface on which fractured or 20 broken bones are attached to ensure the bones remain in position during healing. On a larger scale, the article of the present invention may be used in construction. For instance, the article may form one or more walls of a building, with the mesh portion of the article allowing light to enter the building.

The foregoing describes the invention including preferred forms thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope hereof. 1520632-1 549392 18

Claims (48)

WHAT WE CLAIM IS:

1. A method of expanding a sheet material, at least a portion of which is generally planar and encompasses first and second generally transverse directions, the method 5 comprising the steps of: making a plurality of cuts through a cut area of the sheet material in said at least a portion of the sheet material, wherein the cuts have lengths; and applying a pulling force on the sheet material at least a component of which is transverse to the lengths of at least some of the cuts and at least a component of which is 10 in a direction substantially parallel to at least one of the first and second generally transverse directions to expand the cut area; wherein prior to expansion, in a direction perpendicular to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and in a 15 direction parallel to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and wherein the plurality of cuts are arranged such that the cut area forms a mesh when expanded, and wherein at least part of the cut area curves about each of the first and second directions when the cut area is expanded. 20

2. A method as claimed in claim 1, wherein the step of making a plurality of cuts comprises making a plurality of rows of cuts, with each row comprising a plurality of cuts.

3. A method as claimed in claim 2, wherein the cuts within one row are generally 25 staggered with the cuts in an adjacent row, and the regions between cuts within each row form bond areas, such that the bond areas in one row are generally offset relative to the bond areas in the adjacent row.

4. A method as claimed in any one of claims 1 to 3, wherein the step of making a 30 plurality of cuts comprises making a plurality of linear cuts.

5. A method as claimed in any one of claims 1 to 4, comprising making the plurality of cuts with a laser cutter. 1520632-1 [ - v.1 ! CiVle_ c.™ MZ. j 3 S JX! 2X3 549392 19

6. A method as claimed in any one of claims 1 to 5, wherein the sheet material is sheet metal. 5

7. A method as claimed in any one of claims 1 to 5, wherein the sheet material is sheet plastic.

8. A method as claimed in any one of claims 1 to 7, wherein the curvature of the sheet material once expanded is non-uniform. 10

9. A method as claimed in any one of claims 1 to 8, wherein the mesh comprises a plurality of primary strands and a plurality of secondary strands that differ from the primary strands, wherein the primary strands are connected to each other by secondary strands.

10. A method as claimed in claim 8, wherein a single secondary strand connects adjacent primary strands.

11. A method as claimed in claim 8, wherein a plurality of secondary strands connect 20 adjacent primary strands.

12. A method as claimed in claim 11, wherein the primary strands connect to the secondary strands at primary bond areas, and the secondary strands connect to each other at secondary bond areas. 25

13. A method as claimed in any one of claims 9 to 12, wherein the primary strands deform to a lesser extent than the secondary strands when the cut area is expanded.

14. A method as claimed in any one of claims 9 to 13, wherein the strands have a 30 length and a width, with the width of the primary strands being greater than the width of the secondary strands. 15 1520632-1 0 V .J 549392 20

15. A method as claimed in any one of claims 9 to 14, wherein the primary strands extend substantially the entire length of the mesh portion.

16. A method as claimed in any one of claims 1 to 15, wherein the sheet material 5 comprises material around the cut area, and the method comprises curving at least part of the material around the cut area as a result of expanding the cut area to form the mesh.

17. A method as claimed in any one of claims 1 to 16, wherein the plurality of cuts are arranged in rows, each of which has a length, with a longest row arranged generally in a 10 centre of the cut area and with the length of the rows decreasing as they get closer to a point at which the pulling force is applied to the sheet material.

18. A method as claimed in any one of claims 1 to 17, wherein the pulling force is applied at points adjacent to and externally of the cut area. 15

19. A method as claimed in any one of claims 1 to 18, wherein the pulling force is applied in a direction that is co-planar with the generally planar portion of the sheet material.

20 20. A method as claimed in any one of claims 1 to 19, comprising forming a plurality of cuts in a plurality of discrete cut areas in the sheet material, and expanding those cut areas to form a plurality of discrete meshes.

21. A method as claimed in claim 20, comprising expanding the discrete cut areas 25 concurrendy.

22. A method as claimed in claim 20, comprising expanding the discrete cut areas consecutively. 30

23. A method as claimed in any one of claims 1 to 20, when used to make a chair component.

24. An article made by the method of any one of claims 1 to 23. 1520632-1 llil l_J_' Vi'tJ'" FICS 3 o JLitl 2I3 549392 21

25. An article adapted to be expanded, the article comprising: a sheet material, at least a portion of which is generally planar and encompasses first and second generally transverse directions; and 5 a plurality of cuts extending through a cut area of the sheet material in said at least a portion of the sheet material, wherein the cuts have lengths; wherein the cut area is adapted to expand to form a mesh when a pulling force is applied on the sheet material, with at least a component of the pulling force being in a direction substantially parallel to at least one of the first and second generally transverse 10 directions, wherein in a direction perpendicular to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the iength of cuts decreasing as they get closer to the edge of the cut area, and in a direction parallel to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, 15 and wherein at least part of the cut area curves about each of the first and second directions when the cut area is expanded.

26. An article comprising: an expanded sheet material, at least a portion of which is generally planar and 20 encompasses first and second generally transverse directions prior to being expanded; and a mesh portion on the sheet material, the mesh portion being defined by a plurality of cuts in a cut area that has been expanded, wherein the cut area is in said at least a portion of the material; wherein, prior to expansion, the cuts have lengths, and in a direction perpendicular 25 to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and in a direction parallel to the lengths of at least some of the cuts, the longest cuts are arranged generally in the centre of the cut area, with the length of cuts decreasing as they get closer to the edge of the cut area, and wherein at least part of the 30 expanded cut area is curved about each of the first and second directions as a result of the cut area being expanded. 1520632-1 INTELLEGTU, OrKICc IAL PrtO'r'cri.Y OF N.2. 3 0 :'XA 223 549392 22

27. An article as claimed in claim 25 or 26, wherein the cut area, prior to expansion, comprises a plurality of rows of cuts, with each row comprising a plurality of cuts.

28. An article as claimed in claim 25, wherein the cuts within one row are generally 5 staggered with the cuts in an adjacent row, and the regions between cuts within each row form bond areas, such that the bond areas in one row are generally offset relative to the bond areas in the adjacent row.

29. An article as claimed in any one of claims 25 to 28, wherein the cut area, prior to 10 expansion, comprises a plurality of linear cuts.

30. An article as claimed in any one of claims 25 to 29, wherein the sheet material is sheet metal. 15

31. An article as claimed in any one of claims 25 to 29, wherein the sheet material is sheet plastic.

32. An article as claimed in any one of claims 25 to 31, wherein the curvature of the sheet material once expanded is non-uniform. 20

33. An article as claimed in any one of claims 25 to 32, wherein the mesh comprises a plurality of primary strands and a plurality of secondary strands that differ from the primary strands, wherein the primary strands are connected to each other by secondary strands. 25

34. An article as claimed in claim 33, wherein a single secondary strand connects adjacent primary strands.

35. An article as claimed in claim 33, wherein a plurality of secondary strands connect 30 adjacent primary strands. 1520632-1 'wfEILFVJTUAL PnOHcrtVV CrflCc Or" fV.2. 3 f za ::~3 549392 23

36. An article as claimed in claim 35, wherein the primary strands connect to the secondary strands at primary bond areas, and the secondary strands connect to each other at secondary bond areas. 5

37. An article as claimed in any one of claims 34 to 36, wherein the cuts are arranged such that the primary strands deform to a lesser extent than the secondary strands when the cut area is expanded.

38. An article as claimed in any one of claims 34 to 37, wherein the strands have a 10 length and a width, with the width of the primary strands being greater than the width of the secondary strands.

39. An article as claimed in any one of claims 34 to 38, wherein the primary strands extend substantially the entire length of the mesh portion, and each secondary strand has a 15 length shorter than the primary strands.

40. An article as claimed in any one of claims 25 to 39, wherein the sheet material comprises material around the cut area, and wherein at least part of the material around the cut area is curved as a result of expanding the cut area to form the mesh. 20

41. An article as claimed in any one of claims 25 to 40, wherein the plurality of cuts in the cut area are arranged in rows, each of which has a length, with a longest row arranged generally in a centre of the cut area and with the length of the rows decreasing as they get closer to a point at which the pulling force is applied to the sheet material. 25

42. An article as claimed in any one of claims 25 to 41, comprising a plurality of cuts in a plurality of discrete cut areas, each of which expands to form a plurality of discrete meshes. 30 43. An article as claimed in any one of claims 25 to 42, wherein the article is a chair component. 1520632-1 (ntell!-:otual pa3,^rv

GFFICc OF N.2. 3 0 rfwil LWwJ \ / 549392 24

44. A method of expanding a sheet material as claimed in claim 1, substantially as herein described with reference to any embodiment disclosed.

45. An article adapted to be expanded, substantially as herein described with reference 5 to any one of Figures 2A to 9.

46. An article adapted to be expanded as claimed in claim 25, substantially as herein described with reference to any embodiment disclosed. 10

47. An article comprising an expanded sheet material, substantially as herein described with reference to any one of Figures 2A to 9.

48. An article comprising an expanded sheet material as claimed in claim 26, substantially as herein described with reference to any embodiment disclosed. 15 VICTORIA LINK LIMITED By the authorised agents AJPARK 20 Gf'HCc: Ui" K.Z. 1520632-1 3 0 2wJ3