GB2322221A - Folded sheet - Google Patents

Abstract

A sheet 10 of material having folds in it, the folds comprising a set of concertina radial folds 17,18, meeting at a common point 16 in the centre of the sheet to enable the sheet to be folded flat with the common point 16 defining an apex (27) of a triangular portion (26) of the folded sheet, and having a further fold (31) across said triangular portion (26) to enable the apex (27) to be folded across the folded sheet. The sheet 10 may be provided with a front cover (35) and a rear cover (36) attached together to fold about line (37). The sheet may have a map printed on it.

Description

FOLDED SHEET This invention relates to a sheet of material having folds in it to enable the sheet to be readily folded into a folded sheet, particularly to facilitate storage and sale, and also to be readily unfolded for use in an open and flat state.

The invention is particularly, but not exclusively, directed to such a sheet which has a map printed on it. The folded map should be of a much-reduced size in comparison with its unfolded state to be convenient for sale/purchase, carrying and storage, and be easy to unfold for use, and then to fold up again.

It is an object of the present invention to provide a sheet of material having folds in it, which may be folded to a greatly-reduced size.

The present invention consists ot a sheet of material having folds in it, said folds comprising a set of concertina radial folds meeting at a common point in the centre or in the vicinity of the centre of the sheet to enable the sheet to be folded flat with the common point defining an apex of a triangular portion of the folded sheet, and a further fold across said triangular portion to enable the apex to be folded across the folded sheet.

Preferably said folds also comprise an additional fold to enable the folded sheet with the apex folded across It to be folded yet again.

The additional fold may be parallel to, or perpendicular to said further fold.

Preferably also each concertina radial fold directed towards a corner of the sheet has a reverse-fold portion from said corner to a reverse point of the radial fold, and has two perpendicularly disposed back folds from the reverse point to a respective edge of the sheet to enable the corner to be tucked in.

Preferably further all of the reverse points lie on a common straight line when the sheet is first folded flat, and said further fold is along that common line.

Preferably further the sheet is provided with a front cover and a rear cover attached together to fold towards one another about a line parallel to either any additional fold or, in the absence of any additional fold, to the further fold to enclose the folded sheet.

Preferably further either the front cover or the rear cover is secured to at least a part of the triangular portion of the folded sheet.

Preferably further at least the surface of the sheet to be folded Inwardly has a map printed on it.

Other preferred features of the invent ion will be apparent from the following description and from the subsidiary claims of the specification.

The invention will now be further described, merely by way of example, by reference to the accompanying drawings in which: Figure 1 is a view of an opened and flat map according to a preferred example of the invention, and Figure 2 is a view of the map shown in Figure 1 when It has been partially folded.

Referring now to the drawings, there is provided a rectangular sheet 10 of a suitable material which is able to accept and retain folds for easy folding and unfolding. The lines of the folds may be perforated for this purpose, or to guide initial folding in manufacture. In this preferred example the surface on view in Figure 1 is printed with a map, and the material of the sheet must be able to withstand the unfolding and folding of the map the many thousands of times to be expected in its normal lifetime. Typically the material of the sheet is coatea cartridge paper normally used for maps.

The sheet 10 has folds in it shown in the drawings as dashed lines bearing either circles wit central dots in them, see II, representing arrowheads where the fold tends to rise out of the plane of the flattened open sheet 10, or circles with crosses in them, see 12, representing arrow flights where the fold tends to sink below the plane of the flattened open sheet 10.

Each fold is described below.

As shown in Figure 1, the sheet 10 has a top edge 13, a bottom edge 14 and two side edges 15. Because the sheet is rectangular, opposite edges are of equal length but the top and bottom edges 13,14 are longer than the side edges 15. The sheet 10 could be square with all edges of the same length, or of other symmetrical shape, such as circular.

The sheet 10 is provided with a set of radial concertina folds meeting at a common point 16 either in the centre of the sheet 10, as in this preferred example, or in the vicinity of the centre of the sheet 10 if the folds are required to be somewhat offset. The set of radial concertina folds consists firstly of a vertical fold 17 across the sheet 10 parallel to the side edges 15 with the left and right hand halves of the sheet 10 folded backwards to each side of the vertical fold 17. In the flattened sheet, the vertical fold 17 therefore tends to rise out of the plane of the sheet, as denoted by its arrowheads 11.

The set of radial concertina folds also consists of two mutually perpendicular diagonal folds 18 across the sheet 10 and symmetrical with the vertical fold 17. The diagonal folds 18 are directed towards the corners of the sheet 10, but reach the top and bottom edges 13,14 just inwards of the corners because the sheet 10 is not square; for a square sheet the diagonal folds 18 would exactly zsincie with the diagonals of the square. Each diagonal fold 18 is generally of opposite fold relative to the vertical fold 17, with the sheet halves to each side of it folded upwards to meet each other.

~onseauently, apart from a reversal described below, the diagonal folds 18 tend to sink below the plane of the flattened open sheet 10, as denoted by the arrow flight symbols on them.

The reversal mentioned just above is in the fold direction of the diagonal folds 18. Each diagonal fold 18 has a portion 19 which extends from a reverse point 20 at least one third of the length of the diagonal fold 18 from the common point 16, to the corner of the sheet 10. Each portion 19 is reversed in its direction of fold, so that each of the four portions 19 has the same fold direction as the vertical fold 17. Each reverse point 20 also coincides with the ends of two perpendicularly mutually disposed back folds 21 normal to respective edges of the sheet 10 and folded oppositely to the portions 19.

As thus far described, the sheet 10 may be folded by lifting the centres of the side edges 15 whereupon the sections of the vertical fold 17 and diagonal folds 18 above the common point 16 begin to concertina together, the sections of the vertical fold 17 and the diagonal folds 13 below the common point 16 begin to concertina together, and the portions 19 start to raise the corners of the sheet 13. ContInued lifting of the centres of the side edges 15 until they meet each other completes the concertina folds above and below the common point 16 and tucks the four corners n, producing a folded sheet which can be laid down flat as shown n Figure 2 of the drawings, and which can be as small as one sixth sf the area of the unfolded sheet.

Referring now to Figure 2, the folded sheet 10 has a rectangular portion 25 contiguous with the base of a triangular portion 26. The apex 27 of the triangular portion 26 is the reverse side of the sheet 10 at the common point 16. The sloping edges 28 of the triangular portion 26 are the reverse sides of the diagonal folds 18. The side 29 of the rectangular portion 25 opposite the triangular portion 26 is constituted by the side edges 15. The opposite sides 30 of the rectangular portion 25 at each end of the site 29 are the folded over top edge 13 and bottom edge 14 respectively.

A further fold 31 across the triangular portion 26 adjacent the rectangular portion 25 now enables the rectangular portion 25 to be folded across the triangular portion 26, almost halving again the size of the folded sheet to one twelfth of the area of the unfolded sheet. The further fold 31 is formed by four straight folds 32 forming a square joining together the reverse points 20 and shown in Figure 1. The left hand straight fold 32 tends to rise from the flattened sheet as do the right hand halves of the upper and lower straight folds 32. The right nand straight fold 32 and the left hand halves of the upper and lower straight folds 32 tend te sink below the plane of the -'attened sheet 10.

Figure 2 also shows a front cover 35 and a rear cover 36 for the folded sheet 10. The covers 3,36 are attached together to fold towards one another about a line 37 perpendicular to the further fold 31 and coincident with an additional fold 38 joining the apex 27 to the centres 39,40 of the side edges 15 across the folded sheet as seen - Figure 2. The direction of told of the additional fold 38 is reversed where it crosses the rectangular portion 25. The additional fold 38 is also shown in Figure 1 with its reversals of told direction.

The front cover 35 is glued to the upper part of the reverse face of the triangular portion 25 and the rear cover 36 is glued to the lower part of the reverse face of the rectangular portion 25. Consequently, the steet 10 is fully sandwiched by the front and rear covers when it is fully folded about the further fold 31 and then the additional fold 38, taking the size of the folded sheet down to one twenty-fourth of the open sheet.

In order to open the fully folded sheet 10, the covers 35,36 are opened from each other, hInging about the line 37 and causing the folded sheet to open about the additional fold 38 and then begin to open about the further fold 31. The front centre 39 opposite the apex 27 can then be lifted away from the centre 46 and the sheet fully unfolded. The springy nature of the sheet 10 enables it to be readily folded up again with the classing of the covers 35,36 causIng folding of the additional fold 38. Tabs (not shown can facilitate separation of the front and rear centres 39,40 or the common poit 16 can be slightly offset to the left or right (as viewed in Figure 1) for this purpose.

In a modifIcation of the preferred example, the additional fold 38 Is parallel to the further fold 31 instead of perpendicular to it. In one case, the sheet 10 may be much wider than its length, producing a very wide rectangular portion 25 with the further fold 38 midway between the further fold 31 and the side 29. The front and rear covers 5,36 are always glued to the sheet 10 to each side of and to hinge about the additional fold 38 to fully enclose the folded sheet.

In another modification of the preferred example, the additional fold 38 is omitted. Figure 2 is then further amended by the front cover 35 replacing both covers 35,36 as shown, a new rear cover 36 of similar size to the front cover being behind and covering the rear of the rectangular portion 25, and the fold 37 coinciding with the further fold 31.

Claims (1)

1. A sheet (10) of material having folds in it, said folds comprising a set of concertina radial folds (17,18) meeting at a common point (16) in the centre or in the vicinity of the centre of the sheet to enable the sheet to be folded flat with the common point (16) defining an apex (27) of a triangular portion (26) of the folded sheet, and a further fold (31) across said triangular portion (25) to enable the apex (27) to be folded across the folded sheet.

2. A sheet according to Claim 1 wherein said folds also comprising an additional fold (38) to enable the folded sheet with the apex (27) folded across it to be folded yet again.

3. A sheet according to Claim 2 wherein the additional fold (38) is parallel to said further fold (3i).

4. A sheet according to Claim 2 wherein the additional fold (38) is perpendicular to said further fold (31).

5. A sheet according to any one of the preceding Claims wherein each concertina radial fold (18) directed towards a corner cf the sheet has a reverse-fold portion (19) from said corner to a reverse point (20) of the radial fold (18), and has two perpendicularly disposed back folds (21) from the reverse point (20) to a respective edge (13,14,1so of the sheet to enable the corner to be tucked in.

5. A sheet according to Claims i and 3 wherein all of the reverse points (20) lie on a common straight line when the sheet is first folded flat, and said further fold (31) is along that common line.

7. A sheet according to any one of the preceding claims provided with a front cover (35) and a rear cover (36) attached together to fold towards one another about a line (37) parallel to either any additional fold (38) or, in the absnece of any additional fold, to the further sl (31) to enclose the folded sheet.

8. A sheet according to Claim 7 wherein either the front cover (35) or the rear cover (36) is secured to at least a part of the triangular portion (26) of the folded sheet.

9. A sheet according to any one of the preceding claims in which at least the surface of the sheet to be folded inwardly has a map printed on it.

10. A sheet of material substantIally as wherein described with reference to and as shown in the accompanying drawings.