WO2013096978A1

WO2013096978A1 - Polyhedral body

Info

Publication number: WO2013096978A1
Application number: PCT/ZA2012/000095
Authority: WO
Inventors: John Stegmann
Original assignee: John Stegmann
Priority date: 2011-12-22
Filing date: 2012-12-20
Publication date: 2013-06-27

Abstract

A polyhedral body which is formed by folding segments, on an injection moulded sheet of material which carries a label, about respective lines of weakness so that complementary formations on adjacent segments can be interengaged with one another.

Description

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POLYHEDRAL BODY

BACKGROUND OF THE INVENTION

[0001] This invention relates to a polyhedral body and to a method of making this type of body. The invention is described hereinafter with particular reference to the manufacture of a cube i.e. a six-sided body of regular dimensions but this is exemplary only and is non-limiting.

[0002] Cubes which are marked on most or all of their faces, with printing or by means of other techniques, are commonly used in puzzles, as children's toys and for promotional purposes. Typically a printed image is applied to at least some of the faces. Manufacturers attempt to utilise industrial high speed printing techniques which invariably require the use of sheet material. In order to print on a cube some degree of adaptation and compromise is called for, even if use is made of a digital printer which is capable of printing on a three-dimensional object.

[0003] A cube can be made in various ways, for example as a solid wooden body to which printing or printed paper is applied. A cube can also be made from cardboard or from stitched and stuffed printed cloth. The availability of plastics has led to the manufacture of solid plastic cubes and hollow plastic cubes. A variation is a hollow clear plastic cube which contains a close fitting, folded, printed paper or cardboard cube.

[0004] An object of the present invention is to provide a method of making a polyhedral body, typically a cube, in a high speed manner and to predetermined quality .

characteristics, which can have durable full colour printing on all faces of the polyhedron with the faces being precisely registered with respect to one another.

SUMMARY OF THE INVENTION

[0005] The invention provides a method of making a polyhedral body which includes the steps of forming a sheet of material with a plurality of lines of weakness which divide the sheet into a plurality of segments, each segment being of a defined shape, and respective lines of weakness being located at junctions of adjacent segments, with the sheet including a periphery, a first side and a second side which is opposed to the first side, folding segments relative to adjacent segments about the respective lines of weakness so that surfaces of adjacent segments, formed by respective portions of the second side, subtend an angle which is less than 180° between them, and placing edges of respective segments formed by peripheral portions of the sheet into contact with one another thereby to form a polyhedral body.

[0006] The sheet and the lines of weakness may be formed in any appropriate way for example by means of a press, a stamping operation, through the use of die cutting techniques, or the like. Preferably the sheet is injection moulded from a suitable plastics material.

[0007] Before the segments are folded at least one label may be applied to the first side thereby to cover at least partially at least some of the segments.

[0008] The label is preferably pre-printed. The label may be made from any appropriate material. The label is preferably made from a plastics material and, when use is made of an injection moulding technique to form the sheet, the sheet may be moulded so that it becomes integral with the plastic material.

[0009] The plastic label may have a shape which, in outline, is identical to the outline shape of the sheet of material i.e. the shape formed by its periphery. In an alternative approach the plastic label has a shape similar to the outline shape of the sheet of material although the plastic label may be smaller in size than the outline shape.

[0010] Each line of weakness may be formed by a portion of the sheet which is of reduced thickness compared to the remainder of the sheet. Each segment, at its edges, may be tapered in thickness e.g. mitred.

[0011] In one preferred form of the invention adjacent segments have complementary formations on opposing sides of a common line of weakness which are interengaged with one another when the segments are folded, as aforesaid.

[0012] Frictional forces may be employed, particularly arising from the use of the aforementioned interengageable complementary formations, to ensure that the folded sheet is retained in a desired polyhedral form. It is possible though to make use of adhesives or welding techniques to enhance the strength of the final product.

[0013] In one preferred form of the invention used for the manufacture of a cube a sheet of material is divided into a first strip which includes three square segments and a second strip which includes three square segments, wherein a third segment in the first strip is connected to a first segment in the second strip along a line of weakness which is selected so that with both strips horizontal the third segment in the first strip is positioned above and overlies the first segment in the third strip. This is exemplary only - other configurations of the sheet can also be made to facilitate the formation of a cube.

[0014] In a different form of the invention there is provided a method of making a polyhedral body which includes the steps of forming a label which is divided, at least notionally, into a plurality of sections, forming a plurality of segments from a suitable material, adhering each segment to a corresponding section of the label, folding adjacent sections and corresponding segments relatively to each other and securing the segments together to form a polyhedral body.

[0015] With this form of the invention the label is used to interconnect the segments with the folding of the label taking place about lines, between adjacent sections, which act as hinge points.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 is a view in plan of one form of a label used in the manufacture of a cube in accordance with the invention,

Figure 2 shows a reverse side of the label of Figure 1 ,

Figure 3 depicts schematically an injection moulding process used in the manufacture of the cube,

Figure 4 shows a product produced in the injection moulding step,

Figure 5 is a view in cross section of the injection moulded product, on an enlarged scale, taken on a line 5-5 in Figure 4, Figure 6 shows, in perspective, a cube produced using the techniques of the invention, Figure 7 shows locking formations included in the cube,

Figures 8 and 9 are plan and elevation views respectively of a segment according to a different form of the invention, and

Figure 10 illustrates a half section of a cube made using a number of segments of the type shown in Figures 8 and 9.

DESCRIPTION OF PREFERRED EMBODIMENT

[0017] Figure 1 of the accompanying drawings illustrates in plan a label 10 which is made from a suitable flexible plastic material. Figure 1 shows what is referred to as an inner side 12 of the label while Figure 2 shows what is referred to as an outer side 14 of the label. In Figure 2 the label is inverted relative to the arrangement shown in Figure 1. The inner side 12 is devoid of markings. The outer side 14 is pre-printed using a suitable industrial printing technique so that the side 14 is notionaily divided into six squares, each designated 16. Each square carries printing or marking 18 of any appropriate kind.

[0018] In a manufacturing step (Figure 3) the label 12 is loaded, using automatic or manual techniques, into a mould 22. The mould has a female section designated 24 into which the label 12 fits. An injection moulding machine 26 is then used to inject plastic of a suitable kind into the mould. This is done in accordance with standard injection moulding techniques. What is important here however is that in the injection moulding process a plastic sheet 30 is produced, see Figure 4, which has the same shape as the label. Additionally the label, being made from a plastic material, is moulded onto the sheet and forms an integral whole together with the sheet. [0019] Referring as well to Figure 5, the sheet 30 has a first side 32, to which the label is bonded. On a second side 34, i.e. the side which is visible in Figure 4, the sheet is formed with five lines of weakness 38A to 38E. Each line is positioned so that, in conformance with the squares shown in Figure 2, the sheet is effectively divided into six segments 40 to 50 each of a square outline. The segments are positioned in a first strip 52 and a second strip 54. Each strip has three segments. The strips are interconnected via a line of weakness 38C which is located between the third segment 44 in the first strip and the segment 46 in the second strip.

[0020] Figure 5 shows, in cross section, a line of weakness 38B between the segment 44 and an adjacent segment 42. The line of weakness is formed by a deep V-shaped channel 52 which leaves a thin fold line 56 between adjacent segments. The sides of the segments are bevelled or mitred to angles which are approximately 50°. Similarly an edge 60 of the sheet is mitred. This mitre angle reduces the possibility of a particle on a mitred surface preventing adjacent segments from being positioned at precisely 90° to each other.

[0021] In a subsequent step the sheet 30 is folded to form a cube 62 as is shown in Figure 6. Each segment is folded relative to an adjacent segment so that the side of segment which does not carry the label is moved to an angle of approximately 90° relative to the adjacent segment. The fold lines 38A, 38B, 38D and 38E are in Figure 4 all vertically disposed and folding therefore takes place in a horizontal direction. The line of weakness 38C however is horizontally disposed and folding therefore takes place in a vertical direction. In this way the various segments are brought into a cubic form. [0022] In the moulding process each segment is formed with a pair of formations adjacent each edge. The formations are marked X and Y in Figure 4. Figure 7 illustrates the formations on an enlarged scale. The formations X consist of spaced apart projections designated X1 and X2. The formation Y consists of a single projection marked Y1. The positions of the projections or formations are alternated. Thus when one segment is folded through 90° relative to an adjacent segment each formation Y1 on the respective segment slips into the spaced apart projections X1 and X2 on the other segment - this occurs with a tight frictional fit. In this way the segments are firmly secured to each other. The folding process is enhanced by the bevelled edges of the segments. The X and Y formations are preferably shaped and positioned so as to help to establish a desired fold angle between adjacent segments. The number and shape of the formations can be varied as appropriate to achieve satisfactory performance. Thus the described and illustrated features of the formations in Figure 7 are exemplary only and are non-limiting.

[0023] The sheet material is capable of bending around each line of weakness. Although each line of weakness reduces the strength of the sheet of material it is to be borne in mind that the flexible plastic label which is adhered to the sheet helps to stiffen the folded sheet.

[0024] The folded sheet can be kept in a cubic form merely by means of the interengaged formations X and Y. Use can however be made of an adhesive to strengthen the bonds in the final product. Alternatively use can be made of welding or similar techniques to fix the sides together. [0025] The end product is a cube of regular shape which is produced in an effective, efficient manner to a high quality standard, and rapidly, using appropriate injection moulding and material handling techniques. Embellishments on the cube can take on any suitable form determined only by the nature of the printing on the label.

[0026] In the preceding explanation the sheet material is integrally formed although it is divided into a plurality of segments with adjacent segments separated from one another by means of respective lines of weakness. The plastic label is adhered to the segments. In a different approach the flexible plastic label is notionally divided into sections and is used with a plurality of segments which, effectively, are separately formed i.e. the segments are not directly linked to each other. Instead the segments are adhered to the plastic label which provides a hinge joint between adjacent segments which, otherwise, are separable. With this approach the preformed label is placed in a mould and each of the segments is "over moulded" onto the label. A fold line between adjacent segments is thus formed by the label material only.

[0027] Figures 8 and 9 are an inside plan view, and a view in elevation, respectively of a segment 80 which is one of six similar segments (the balance are not shown) which are used to make a cube. An inspection of Figure 7 shows that the formations are in the nature of upstanding tubular projections with tapered upper ends 84 and sides 86 which are at right angle to a planar inner surface 88 of the segment.

[0028] The segment is bevelled along its four edges. The level angle 90 is 50°. This ensures that when adjacent segments are positioned at a right angle to each other any small particles of dirt or other material on a mitred face cannot unduly interfere with the positioning of the segments correctly relative to one another. [0029] Figure 10 is a view in section of a cube formed from the segment 80 and four side segments 80A to 80D respectively. The manner in which the formations interact and engage with one another is apparent particularly from this Figure.

[0030] It is possible, apart from applying the labels to the segments, to decorate one or more segments, using any suitable technique, before or after assembly of the segments into a polyhedral body.

Claims

WO 2013/096978 -| Q , PCT/ZA2012/000095CLAIMS

1. A method of making a polyhedral body which includes the steps of forming a sheet of material with a plurality of lines of weakness which divide the sheet into a plurality of segments, each segment being of a defined shape, and respective lines of weakness being located at junctions of adjacent segments, with the sheet including a periphery, a first side and a second side which is opposed to the first side, folding segments relative to adjacent segments about the respective lines of weakness so that surfaces of adjacent segments, formed by respective portions of the second side, subtend an angle which is less than 180° between them, and placing edges of respective segments formed by peripheral portions of the sheet into contact with one another thereby to form a polyhedral body.

2. A method according to claim 1 wherein the sheet is injection moulded from a suitable plastics material.

3. A method according to claim 2 wherein, before the segments are folded, at least one label is applied to the first side thereby to cover at least partially at least some of the segments.

4. A method according to claim 3 wherein the sheet is moulded so that the label becomes integral with the plastic material.

5. A method according to claim 3 or 4 wherein the label has a shape which, in outline is identical, or similar, to the outline shape of the sheet of material. WO 2013/096978 -j -| PCT/ZA2012/000095

6. A method according to any one of claims 1 to 5 wherein each line of weakness is formed by a portion of the sheet which is of reduced thickness compared to the remainder of the sheet and each segment, at its edges, is mitred.

7. A method according to any one of claims 1 to 6 wherein adjacent segments have complementary formations on opposing sides of a common line of weakness which are interengaged with one another when the segments are folded.

8. A method of making a polyhedral body which includes the steps of forming a label which is divided, at least notionally, into a plurality of sections, forming a plurality of segments from a suitable material, adhering each segment to a corresponding section of the label, folding adjacent sections and corresponding segments relatively to each other and securing the segments together to form a polyhedral body.

9. For use in the manufacture of a polyhedral body a sheet of material with a plurality of lines of weakness which divide the sheet into a plurlality of segments, each segment being of a defined shape, and respective lines of weakness being located at junctions of adjacent segments, with the sheet including a periphery, a first side and a second side which is opposed to the first side, each line of weakness being formed by a portion of the sheet which is of reduced thickness compared to the remainder of the sheet, and each segment, at its edges, being mitred, and wherein adjacent segments, on the second side have complementary formations on opposing sides of a common line of weakness which are interengageable with one another when the segments are folded so that the respective surfaces, on the second side, are at 90° relative to each other.