GB2123874A

GB2123874A - Structural systems for panels, boards, shelves, and laminates

Info

Publication number: GB2123874A
Application number: GB08318395A
Authority: GB
Inventors: David Michael Mckay; Stephen James Morgan
Original assignee: BARNVALE Pty Ltd
Current assignee: BARNVALE Pty Ltd
Priority date: 1982-07-07
Filing date: 1983-07-07
Publication date: 1984-02-08
Also published as: AU1691083A; GB8318395D0

Abstract

Structures are developed from substantially planar sheets 10 of relatively inflexible material formed with two interdigitating patterns 11 and 12 of preferred bending. One pattern 11 is designed to facilitate bending out of the plane of the sheet on one side of that plane and the other pattern 12 is designed to facilitate bending out of the plane on the other side thereof. Each pattern 11 or 12 comprises a non-linear backbone 13 or 14 of straight lines 17 or 18, joined in end to end relationship, and having a plurality of straight ribs 15 or 16 extending transversely of the backbone. Each rib 15 or 16 has one end juxtaposed with the junction of two lines 17 or 18 in the backbone of its pattern 11 or 12 and the other end in juxtaposition with the junction of two lines 18 or 17, respectively, in the backbone of the other pattern 12 or 11, the patterns being such that no line crosses a line of the same or of the other pattern. The invention is characterised in that the sum of the angle between a rib 15 or 16 and one of the juxtaposed lines 17 or 18 of the backbone 13 or 14 or its pattern 11 or 12 and the angle between the other of those juxtaposed lines 17 or 18 and the rib 16 or 15, respectively, of the other pattern juxtaposed therewith is not equal to 180 DEG . <IMAGE>

Description

SPECIFICATION Structural systems for panels, boards, shelves and laminates The present invention relates to a substantially planar sheet material provided with two patterns of preferred bending such that the sheet may, by the application of compressive forces in the plane of the sheet develop into a three dimensional array of ridges and valleys. The invention further relates to structures consisting of or including a sheet so developed.

It is known to form planar sheets with two patterns of preferred bending such that upon the application of compressive forces in the plane ofthe sheet develop into a three dimensional array of ridges and valleys.

Such sheets are disclosed in French patent specification 1,349,879, in German patent specification 2,530,661 and in German patent specification 1,434,112. In all of the sheets described in these specifications the patterns of each comprise anon- linear backbone of straight lines, joined together in end to end relationship, and a plurality of straight ribs extending transversely of the backbone. Each rib in each pattern terminates at one end in juxtaposition with the junction oftwo lines in the backbone of that pattern and at the other end in juxtaposition with the junction oftwo lines in the backbone of the other pattern. In all ofthe prior art specifications the rib bisects the angle between the two juxtaposed lines of the backbone of its pattern i.e. the angles between the rib and each of the juxtaposed lines of its backbone are equal.A corollary of this is thatthe sum ofthe angle between a rib and one ofthe juxtaposed lines ofthe backbone of its pattern and the angle between the otherofthosejuxtaposed lines and the rib ofthe other pattern juxtaposed therewith is always equal to 1800.

In this arrangementthe application of compressive forces in the plane ofthe sheet will develop the sheet into a three dimensional array of ridges and valleys.

Further compression will cause the sheet to collapse into a concertina-like array of vertical sheet segments abutting in a face to face relationship i.e. there is a continuous transition between the sheet in a horizontal, planarform and the sheet in a collapsed, concertina-like, form with the sheet segments lying in face to face vertical array.

It will also be apparent that in such a sheet the thickness ofthe developed sheet will be dependent upon the degree of which the sheet has been compressed by the application of forces in the plane of the sheet. Ifthe sheet, when developed, isto have a uniform thickness then the patterns on the sheet must be repeated uniformly. This makes it impossibleto introduce into the sheet localised pattern changes which can result in localised increases in strength in the developed sheet or in structures consisting of or including a sheet so developed.

The present invention is directed to a novei pattern for use in such sheets in which there is a disjunction in the collapsing of the sheet by the application of compressive forces in the plane ofthe sheet such that the sheet "locks up" in a condition in which some of the sheet segments lie in face to face abutment and some lie transversely to such face to face segments.

The novel patterns according to preferred embodi ments ofthis invention allowthe creation of localised areas of increased strength in sheets of uniform developed thickness.

The present invention consists in a substantially planar sheet of relatively inflexible material formed with two interdigitating patterns of preferred bending, one pattern being designed to facilitate bending out of the plane of the sheet on one side of that plane and the other pattern being designed to facilitate bending out ofthe plane on the other side thereof, each pattern comprising a non-linear backbone of straight lines, joined together in end to end relationship, and having a plurality of ribs, constituted by straight lines, extending transversely of the backbone, each rib terminating at one end in juxtaposition with the junction of two lines in the backbone of its pattern and at the other end in juxtaposition with the junction of two lines in the backbone of the other pattern, the patterns being such that no line crosses a line of the same or ofthe other pattern,the present invention being characterised in that the sum ofthe angle between a rib and one ofthejuxtaposed lines ofthe backbone of its pattern and the angle between the other of those juxtaposed lines and the rib of the other pattern is not equal to 1800; such that the sheet is capable, bythe application of compressive forces in the plane ofthe sheet to develop into an array of ridges and valleys which can lock-up (as herein defined).

The present invention further consists in a structure consisting of or including a sheet according to the present invention developed into a three dimensional array of ridges and valleys.

As used in the present specification sheets of the type to which this invention relates are said to lock-up when some segments ofthe sheet defined by the pattern will lie in face to face abutment while other segmentsthereofwill lie transversely to the plane of such face to face abutment.

In preferred embodiments of the present invention each ofthe patterns will be made up of a plurality of identical pattern units placed in a continuous array of side by side and end to end pattern units. In other embodiments however there could be a continuous transition or change in the pattern throughout the sheet. This transition or change in the pattern could comprise changes in the relative angular relationship between lines in the backbone or between such lines and the ribs; it could comprise changes in the lengths ofthe lines in the backbone or the ribs; oritcould comprise a combination of both ofthesefactors.

The two patterns of preferred bending are preferably applied as one pattern on each side ofthe sheet such thatjuxtaposed ends of lines in the two patterns will be separated by the thickness ofthe sheet. The nature of the patterns will vary depending upon the material ofthe sheet. If the sheet were of a relatively rigid thermoplastic material the patterns may be applied by heatto cause lines of weakness, and thus preferred bending, on each side ofthe sheet. In the case of a cardboard sheet the patterns of preferred bending may be cut into each side ofthe cardboard sheet. If sheet were of metal then the pattern could be embossed into the metal with a die.The above examples are illustrative only as other materials could be used to form the sheet and other methods could be used to form in the sheet the patterns of preferred bending.

It is also within the ambit ofthe invention to form the sheetfrom a plurality of sheet segments hingedly connected togetherbyflexible elements. The hinged connections being disposed along the pattern lines.

Each pattern includes a rib terminating injuxtaposi- tion with everyjunction between two lines of the backbone ofthat pattern. Similarly each pattern includes a rib of the other pattern terminating in juxtaposition with everyjunction between two lines of the backbone of that pattern.

In describing the preferred patterns falling within the ambit of this invention it is useful to describe only one unit of each ofthe patterns for any one sheet. This may conveniently be done with reference to a notional rectilinear grid defining the locus ofthejunction between the lines ofthe backbones of the two patterns and ofthejunctions between the ribs and the backbones. In order to facilitate this description the lines ofthe notional grid extending in a vertical direction are given alpha designations e.g. A, B, C. etc., whilethe horizontal lines are given numeric designations e.g. 1,2,3 etc. Thus a pattern which had two backbone lines as the basic unit could be described by a grid having vertical lines A, B and C and horizontal lines 1,2 and 3.A pattern which have four backbone lines in the basic unit could be described by a grid having vertical lines A, B, C, D and E and horizontal lines 1,2 and 3. It will be appreciated thatthe junctions ofthe lines in the patterns do not have to fall on a rectilinear grid howeverforthe purposes of description it is useful to use examples which do.

In one preferred embodiment ofthe invention the pattern unit comprises two backbone lines and has ribs no longerthan one grid unit and may thus be defined by a grid having vertical lines A, B and C and horizontal lines 1,2 and 3. In this preferred embodimentthe distance between lines 1 and 2 is equal to the distance between lines 2 and 3 butthe distance between A and B is greaterthan between B and C. The pattern on one side of the sheet comprises a backbone extending from A2 to B3 to C2 with ribs extending from A2toA1, B2to B1, and C2to C1 .The pattern on the other side of the sheet comprises a backbone extending from Al to B2 to C1 with ribs extending from A2 to A3, B2 to B3, and C2 to C3.This represents probablythe simplest form of the invention and results in a three dimensional structure of uniform thickness defined between two notional planes (hereinafter called a flat structure) which will lock up.

Avariation oftheforegoing may be developed by providing a notional grid in which the distance between lines 1 and 2 does not equal the distance between lines 2 and 3. This embodiment of the invention results in a three dimensional structure which is of uniform thickness and locks up but which lies between two notional curved surfaces i.e. the developed structure is curved rather than flat as in the previous case.

Afurther preferred group of embodiments are those defined by a notional 5 by 3 grid in which the distances between each pair of adjacent vertical and each pair of adjacent horizontal lines is equal. In this embodiment the pattern on one side of the sheet comprises a backbone extending from Al to B2 to C2 to D1 to El with ribs extending from A2to A3, B2 to B3, C2 to C3, D2 to D3 and E2 to E3. The pattern on the other side of the sheet comprises a backbone extending from A2 to B3 to C3 to D2to E2 with ribs extending from Al to A2, Bl to B2,Cl toC2, Dl to D2and El to E2.This embodiment ofthe invention develops into a flat structure which locks up.This structure is interesting because the segments ofthe sheet which do not lie in face to face abutment when the sheet is locked up lie at right angles to the planes of such face to face abutment.

Another embodiment ofthe invention which develops into a very similar structure as the foregoing may be described with reference to the notional grid of the preceeding paragraph. In this embodiment the pattern on one side ofthe sheet comprises a backbone extending from Al to B2 to C2 to D3 to E3 with ribs extending from A2 to A3, B2 to B3, C1 to C2, D1 to D2 and E2 to E3. The pattern on the other side ofthe sheet comprises a backbone extending from A2 to B3to C3 and from C1 to D2 to E2 with ribs extending from Al to A2, B1 to B2, C2to C3, D2to D3 and El to E2. It will be noted that in this case there appears to be a disjunction in the backbone on the other side ofthe sheet.In practice, of course, the backbone is continuous as it progresses from pattern unit to pattern unit.

The foregoing 5 by3 notional grid may be used to produce other embodiments ofthis invention. If the distance 1 to 2 and 2 to 3 are made unequal then a curved lock-up structure will be produced. In another embodiment the distances between A and B, and B and C and C and D and D and E may be non-uniform in which case the spacings between the segments in face to faceabutmentwhen the three dimensional structure locks up will vary. This feature may be used to produce structures having different strengths in different parts ofthe structure.

Embodiments of the invention may also be produced in which separate notional grids are used for the patterns on each side ofthe sheet. Ifthese notional grids are ofthe same dimensions but horizontally and/orvertically displaced from one anotherthe resultant locked up structure will have a stepped form rather than a flat or curved form.

It is also possible to produce patterns based on larger notional grids. Some ofthese may include patterns which show an axis of symmetry, the pattern or each side of the axis being a pattern unit in its own right which if repeated would give rise to a sheet according to this invention. It is also possible forthe notional grid to change abruptlyorgraduallythrough a sheetto give rise to consequent changes in the structure developed from the sheet.

The sheets according to this invention may be formed up into a three dimensional structure, either to the lock up stage orto some intermediate position, and laminated between planar, curved or stepped sheets to form structural laminates. These structural laminates could, for instance, be used as building panels oras impact resistant packing material. The structures formed merely by forming up the sheet into its three dimensional form can, for instance, be used as sound deadening material or as a packaging material. Such structures could also be used as formworkto produce aesthetic surface effects on cast concrete.

Hereinafter given by way of example only are preferred embodiments ofthe present invention described with reference to the accompanying drawings in which: Fig. lisa representation of the two patterns of preferred bending on one embodiment ofthe sheet according to th is invention; Fig. 2 is a perspective view of a locked up three dimensional structure developed from a sheet having the pattern of preferred bending of Fig. 1; Fig. 3 is a representation of the two patterns of preferred bending on a furtherembodimentofthe sheet according to this embodiment; Fig. 4 is a perspective view of a locked up three dimensional structure developed from a sheet having the patterns of preferred bending of Fig. 3; Fig. 5 is a representation ofthetwo patterns of preferred bending on a further embodiment of a sheet according to this invention;; Fig. 6A is a perspective view of a three dimensional structure partly developed from a sheet having the patternofprefered bending of Fig.5; Fig. 6B is a perspective view ofthe structure of Fig.

6A developed to a locked up position; Fig. 7 is a representation ofthe two patterns of preferred bending on a further embodiment of the sheet according to this invention; Fig. 8 is a perspective view of a locked up three dimensional structure developed from a sheet having the patterns of preferred bending of Fig. 7; Fig. 9 is a representation ofthetwo patterns of preferred bending on a further embodiment of a sheet according to this invention; Fig. loins a perspective view of a locked up three dimensional structure developed from a sheet having the patterns of preferred bending of Fig. 9; Fig. 1 1 is a representation of the two patterns of preferred bending on a further embodiment of a sheet according to this invention;; Fig. 12 is a perspective view of a locked up three dimensional structure developed from a sheet having the patterns of preferred bending of Fig. 11; Fig. 13 is a representation of the two patterns of preferred bending on a further embodiment of a sheet according to th is invention; Fig. 14 is a perspective view of locked-up three dimensional structure developed from a sheet having the patterns of preferred bending of Fig. 13; Fig. 15 is a representation ofthe two patterns of preferred bending on a further embodiment of a sheet according to this invention; Fig. 1 6A is a perspective view of a three dimension al structure partly developed from a sheet having the patterns of preferred bending of Fig. 15; Fig. 1 6B is a perspective view ofthe structure of Fig.

16A developed to a locked up position; Fig. 17 is a representation ofthe two patterns of preferred bendingonafurtherembodimentofa sheet according to this invention; Fig. 18 is a perspective view of a three dimensional structure partly developed from a sheet having the patterns of preferred bending of Fig. 17; Fig. 19 is a representation of the two patterns of preferred bending on a further embodiment of a sheet according to this invention; Fig.20 is a perspective view of a locked-up three dimensional structure developed from a sheet having the patterns of preferred bending of Fig. 10;; Fig. 21 is a perspective view of a laminate incorpor ating a three dimensional structure formed from a sheet according to this invention; and Fig. 22 is a container comprising a three dimensional structure formed from a sheet according to this invention.

In the following description of the various embodiments of the invention iliustrated the same numbers will be used for similar integers.

With reference to Figs. 1 and 2 the cardboard sheet loins formed with two patterns of preferred bending.

The first pattern 11, which is shown in dashed lines, defines an array of lines of preferred bending which will rise above the plane of the sheet 10 as depicted in Fig. 1 when the sheet is developed into a three dimensional Fig. The second pattern 12, which is shown in dotted lines, defines an array of lines of preferred bending which will fall below the plane of the sheet 10 when so developed.

The patterns 1 1 and 12areeachformed bycutting into the cardboard through approximately half its thickness. The pattern 11 is formed on the upper surfaceofthesheet loans seen in Fig. land the pattern 12 isformed on the lower surface thereof.

Each of the patterns 11 and 12 comprise a recurring array of abutting pattern units which are in register with one another. Each pattern comprises a backbone,13in pattern 11 and 14in pattern 12,anda pluralityofstraight ribs, 15 in the pattern 11 and 16 in pattern 12. Each of the backbones is non-linear and made up of a pluralityofstraight lines, 17 in pattern 11 and 18 in pattern 12, connected end to end. Each rib 15, 16 is connected at one end to ajunction between two lines 17,18 ofthe backbone 13,14 of its own pattern and is connected at its other end to a junction between two lines 17,18 ofthe backbone 13, l4ofthe other pattern.

The units of patterns 11 and 12 may each be described with reference to a single 3 by grid 3 grid comprising parallel vertical lines A, B and C and parallel horizontal lines 1,2 and 3. In the case of Fig. 1 the distance between 1 and 2 equals the distance between 2 and 3 but the distance between A and B is greater than the idstance between B and C. The spacing between lines A, B and C meansthatthe angles between each rib 15, 16 and the adjacent lines 17,18, is not equal and thus the sum of the diagonally opposed pairs of angles or and T, and ss and 6, are not equal to 180 . In the case of pattern 11 the angle between line 17 extending from Al to B2 and the rib 15 extending from B2 to B3 issmallerthan the angle between that rib 15 and the line 17 extending from B2 to C1.

As is seen in Fig. 2 compression of the sheet 10 of Fig. 1 in the plane ofthe sheet developes the sheet into a three dimensional structure comprising an array of ridges and valleys. Because of the angular relationship between the ribs 15, 16 and the lines 17, 18 ofthe backbones 13,14the segments ofthe sheet between B and C lines of the grid will come into face to face abutment while the segments between the A and B lines arestill extending transverselyto the plane of that abutment i.e. the structure "locks-u p" before it is fully collapsed. In the embodiment ofthe inventionshownin Fig.2thethreedimensional structure is flat, i.e. the crests ofthe ridges and valleys lie in two parallel planes.

The embodiment shown in Figs. 3 and 4 is similarto that shown in Figs. and and 2 exceptthatthe distance between grid lines 1 and 2 is smallerthan that between lines 2 and 3. Athree dimensional structure similarto that of Fig. 2 can be developed from the sheet of Fig.3 exceptthatthe structure is curved.

The embodiment shown in Fig. 5, 6A and 6B is similarto that shown in Figs. 1 and 2 exceptthatthe grid is square but based on a 5 by 3 unit ratherthan a 3 by3 unit This allows the angles between each rib 15, 16 and the adjacent lines 17,1 8to be unequal without the spacings between lines A, B, C, D and E being unequal. As is seen in Figs. 6A and 6B the sheet 10 of Fig. 5 develops a flatthree dimensional structure and locks-up.

Theembodimentshown in Figs.7 and 8isvery similarto that shown in Figs. 5, 6A and 6B exceptthat the backbones ofthe embodiment of Fig. Shave an essentially wave-like form whereas those of Fig. 7 have an essentially stepped form.

The embodiment shown in Figs. 9 and 10 is similar to that of Figs. 5, 6A and 6B exceptthatthe spacing between lines 1 and 2 is greaterthan the spacing between lines 2 and 3. As is seen in Fig. 10 the sheet 10 of Fig. 9 develops as a curved three dimensional structure which locks-up.

The embodiment shown in Figs. 11 and 12 is similar to that of Figs. 5, 6A and 6B exceptthatthe spacings between lines A, B, C, D and E are not equal. As is seen in Fig. 12 the sheet 10 of Fig. 11 develops as a flat three dimensional structure which locks up. In this case the segments between the A and B lines lock-up before any ofthe other segments come into face to face contact, thus all the segments lie transversely to the A, B segments when the structure is locked-up.

Theembodimentshown in Figs. 13 and 14issimilar to that of Figs. 5, 6A and 6B exceptthatthe patterns 11 and 12 are based on grids which are displaced from one another in a vertical direction. As is seen in Fig. 14 the sheet 10 of Fig. 13 develops as a stepped three dimensional structure which locks-up.

The embodiment shown in Figs. 15, 16A and 1 6B is similarto that of Figs. 5, 6A and 6B exceptthat the patterns 11 and 12 each comprises the 5 by 3 unit of Fig. Stogetherwith the mirror image of that unit. The pattern unit ofthe embodiment of Fig. is thus based on a 5 by 5 grid rather than a 5 by 3 g rid. Itwill be noted that in this embodiment the patterns 11, 12 includes notonlythe backbones 13,14 and ribs 15,16 but but also successive islands 19,20 isolated from the remainder of that pattern 11, 12 by the other ofthe patterns 12,1 l.As is seen in Figs. l6Aand and 16B the sheet 10 of Fig. 15 develops into a corrugated locked-up structure.

The embodiments shown in Fig. 17 and 18 is very similarto that of Figs. 1 5, 16A and 16B exceptthatthe patterns 11 and 12 are stretched such that they are based on a5 by7 grid ratherthan a 5 by5grid. Fig. 18 shows a three dimensional structure formed from the sheet 10 of Fig. which has been only partly developed and stopped prior to reaching the lockedupstage.

The embodiment shown in Figs. 19 and 20 is the same as the embodiment shown in Figs. 5, 6A and 6B except that there is a horizontal dimensional transition from the grid designated 1,2 and 3 to the grid designated 1 2' and 3'. This dimensional transition is reflected in the change in thickness ofthe developed, locked-up, structure shown in Fig. 20.

Fig. 21 shows a laminated structure comprising the structureofFig.6Bsandwiched between two planar sheets. Fig. 22 shows a containerformed from the developed structure of Fig. 6B.

Claims

1. A substantially planar sheet of relatively inflexible material formed with two interdigitating patterns of preferred bending, one pattern being designed to facilitate bending out of the plane ofthe sheet on one side ofthat plane and the other pattern being designed to facilitate bending out of the plane on the othersidethereof,each pattern comprising anon- linear backbone ofstraight lines, joined together in end to end relationship, and having a plurality of ribs, constituted by straight lines, extending transversely ofthe backbone, each rib terminating at one end in juxtaposition with thejunction oftwo lines in the backbone of its pattern and atthe other end in juxtaposition with the junction oftwo lines in the backbone of the other pattern,the patterns being such that no line crosses a line ofthe same or of the other pattern, the present invention being characterised in thatthe sum of the angle between a rib and one ofthe juxtaposed lines ofthe backbone of its pattern and the angle between the other ofthose juxtaposed lines and the rib ofthe other pattern is not equal to 1800; such that the sheet is capable, by the application ofcompressiveforces in the planeofthe sheet to develop into an array of ridges and valleys which can lock-up (as herein defined).

2. A substantially planar sheet of relatively inflexible material as claimed in claim 1 in which each of the pattern is made up of a plurality of pattern units placed in side by side and end to end register.

3. A substantially planar sheet of relatively inflexible material as claimed in claim 1 in which one pattern of preferred bending is applied to one side of the sheet and the outer pattern of applied bending is applied to the other side ofthe sheet.

4. A substantially planar sheet of relatively inflexible material as claimed in claim 1 in which the angle between a rib and one of the juxtaposed lines ofthe backbone of its pattern is 90".

5. A substantially planar sheet of relatively inflexible material as claimed in claim 2 in which each pattern unit is based on a national grid comprising three longitudinal linesandfivevertical lines.

6. A substantially planar sheet of relatively inflexible material as claimed in claim 5 in which the grid upon which each pattern unit is based has the longitudinal lines uniformly spaced and the vertical lines non-uniformly spaced such that when developed the three dimensional structure formed by the sheet is stepped.

7. A substantially planar sheet of relatively inflexible material as claimed in claim 5 in which the grid upon which each pattern unit is based has the horizontal lines non-uniformly spaced such that when developed thethree dimensional structure formed by the sheet is curved.

8. A structure consisting of and including a sheet as claimed in any one of the preceding claims.

9. A sheet of relatively inflexible material substantially as hereinbefore described with reference to, and as shown in, Figs. 1 and 2, or Figs 3 and 4, or Figs. 5, 6A, and 6B,or Figs 7 and 8, or Figs. 9 and 10, or Figs.

11 and 12, orFigs.13and 14, orFigs.15,16A,and 16B, or Figs. 17 and 18, or Figs. 19 and 20, or Fig. 21, or Fig.

22, of the accompanying drawings.