WO2003060258A2

WO2003060258A2 - Assembly of a frame and a cloth to be stretched thereon

Info

Publication number: WO2003060258A2
Application number: PCT/NL2002/000866
Authority: WO
Inventors: Aart Van Der Stigchel
Original assignee: New Business Initiatives B V; Aart Van Der Stigchel
Priority date: 2001-12-28
Filing date: 2002-12-23
Publication date: 2003-07-24
Also published as: WO2003060258A3; NL1019677C2; AU2002360011A1

Abstract

Assembly of a frame and a cloth to be stretched thereon, comprising: - at least one first frame part comprising at least two first arms mutually pivotable via a first pivot member, - at least one second frame part comprising at least one second arm, - wherein the first pivot member of the first arms is slidable along a second arm.

Description

ASSEMBLY OF A FRAME AND A CLOTH TO BE STRETCHED THEREON

Foldable tents are known which consist of foldable, rectangular panels, wherein tent poles run along the diagonals of these panels. Such tent poles are fixed to the corner points of the tent-cloth as well as to a pivot point in the centre of the tent-cloth. The erection of such a tent takes place by unfolding the tent-cloth with the four poles. The length of the poles is herein slightly greater than the length of the diagonals of the cloth, whereby some force is required to press the tent poles with the pivot point against the cloth. The pivot point of the four poles is herein pressed into a bulge in the tent-cloth, wherein the poles are pressed over a dead point due to the tension between the ring of the cloth and these poles. The panel hereby acquires some firmness. Such tent panel constructions have drawbacks however, such as for instance that the wind can blow into^: such panels, such panels can be pushed in accidentally by a person or that guy ropes are required to stabilize such a tent. In order to obviate such drawbacks, the present invention provides an assembly of a frame and a cloth to be stretched thereon, comprising:

- at least one first frame part comprising at least two first arms mutually pivotable via a first pivot member,

- at least one second frame part comprising at least one second arm,

- wherein the first pivot member of the first arms is slidable along a second arm. The assembly according to the present invention has the advantage that it can be erected very easily by for instance one person. A further advantage is that, because the first pivot member is slidable along the second arm, a very high tension can be applied to the cloth, whereby relatively long and relatively rigid rods which are difficult to bend can be used as arms. In an assembly according to the invention the panel is formed by sliding the first pivot member along the second arm during stretching of the assembly.

In a preferred embodiment the second frame part comprises a second pivot member for pivoting two or more arms. In this embodiment it becomes possible to manufacture square or polygonal assemblies.

In a further preferred embodiment the outer ends of the arms are connected to corner points of at least one cloth in order to stretch the cloth using the frame. This embodiment makes it possible, using the frame, to manufacture for instance tents, umbrellas or screens.

In preference the arms are longer and/or the sum of two arms together lying substantially mutually in line is longer than half a diagonal of the cloth. A diagonal of the cloth is herein defined as twice the distance of a first or second pivot member to a respective corner point to which such a pivot member is connected by means of an arm. That the arms are longer than half a diagonal has the advantage that, if the pivot members are forced against the cloth by sliding a first pivot member, the cloth is hereby tensioned, wherein the tension becomes greater as the difference between the length of the arms and the half-diagonal becomes greater. A suitable ratio of arm length/half-diagonal length can be chosen depending on the type of cloth and the type of material from which the arms are manufactured.

The arms are preferably rods which are flexible to at least some extent. If the arms are flexible, the arms take on an arcuate form between a corner point and a pivot member when they are under tension. The embodiment hereby also acquires an aesthetically pleasing bulging form. A correctly chosen flexibility of the rods has the advantage that a stable construction is obtained. The rods preferably comprise fibre glass. Very strong but also flexible rods can be obtained using this material. In a further embodiment the cloth has a substantially non-stretching periphery. In order to obtain a suitable bulging in a stretched cloth, it is important that the edges of the cloth do not stretch during the stretching or when in stretched state. It is herein advantageous that the corner joints between the arms and the cloth absorb forces without stretching the cloth along the edges. For this purpose the cloth is preferably strengthened along the edges thereof with strengthening means, such as band material or the like. In view of the relatively high tension under which the cloth can be stretched using embodiments according to the present invention, it is recommended that the cloth is additionally strengthened, mainly along the edges, in order to be able to bear such forces.

In further embodiments the first and/or second pivot members comprise a pivot means for each arm connected thereto. This pivot means preferably comprises a shaft or pin. An advantage hereof is that, in the folded-up state of the assembly, the arms or rods can pivot independently of each other and adjacently of each other, whereby the arms can be arranged parallel without twisting when the assembly is folded up.

The second arm, along which the first pivot member slides, preferably comprises a covering with a low friction. Sliding of the first pivot member along the second arm hereby becomes easier, whereby the erection of the assembly becomes simpler and for instance requires less force. The first pivot member preferably further comprises a sliding member which encloses the first arm along which the first pivot member slides, and this part is sufficiently long to distribute the frictional forces over a relatively large surface area. The guiding of the first pivot member along the second arm is hereby improved.

In a further preferred embodiment the first pivot member further comprises an engaging part for guiding this part along the arm, which part can for instance be embodied as an optionally pivoting rod which can be used for a better engagement by the person operating the first pivot part. The sliding movement force can hereby be applied in simple manner. A force can for instance further be exerted to release the bending force of the arms in order to reduce possibly remaining friction between the first pivot part and the second arm.

In a further preferred embodiment the first pivot member is slidable along the second arm further than halfway along the diagonal or arcuate diagonal extending substantially along this arm. The second pivot member for instance is herein placed further than halfway along the diagonal or arcuate diagonal, so that the second arm along which the first pivot member is slid is a little longer than half the diagonal. It is hereby possible to slide the first pivot part beyond the "dead" point of the tensioning, whereby it is fixed in the arms and the cloth by the tension.

The smallest angle between two frame parts preferably lies in the interval of 35-90 degrees.

The bending of the arms due to the stretching is preferably up to 15 percent of the diagonal length. This enables a great tension on the cloth, the cloth edges and the arms . In a particular embodiment the assembly comprises at least two pairs of the frame parts, which each comprise a first frame part and a second frame part, wherein the pairs of frame parts mutually overlap in that two pairs of two arms are arranged crossing each other. An advantage of such a preferred embodiment is that the outer ends of the combined assembly, when they are pulled toward each other under tension, further increase the bending tension, whereby an even more stable assembly is created than on the basis of only the bending tension of the sliding crosses.

A further aspect of the present invention comprises at least two overlapping frame parts, each comprising four arms and cloth for stretching thereon, further comprising:

- fourfold pivot means for holding together and pivoting the arms per frame part, wherein the frame parts are flexible and wherein cloth can be stretched by means of tensioning means and the arms of the frame parts.

A particular embodiment hereof comprises three such crosses. Using this embodiment a tent assembly can be erected very simply by folding out four arms per cross and pulling toward each other the outer corner points of the thereby created rectangle by means of the tensioning means. Because points of the mutually overlapping arms tension the cloth by bending the whole, the assembly becomes very stable.

A further aspect of the present invention provides a method for stretching a polygonal cloth, comprising the following steps of:

- partly folding out at least three arms which form part of at least two frame parts, - forming at least one frame part using these arms which comprises at least an arm along at least one diagonal or perpendical line of a polygonal cloth,

- sliding a pivot member along one of the arms along the diagonal or perpendical line in order to force all arms under tension against the cloth.

Further features and details of the present invention will be elucidated with reference to the annexed figures, wherein: - figure 1 is a perspective view of a node of four ribs according to an embodiment according to the present invention;

- figures 2-4 are perspective views of an embodiment according to the present invention; - figure 5 is a cut-away perspective view of a further embodiment according to the present invention;

- figure 6 is a cut-away perspective view of a further embodiment according to the present invention;

- figure 7 is a cut-away perspective view of a further embodiment according to the present invention;

- figures 8-12 are perspective views of a further embodiment according to the present invention;

- figure 13 is a perspective view of a further embodiment according to the present invention; - figure 14 is a perspective view of a further embodiment according to the present invention;

- figure 15 is a perspective view of a further embodiment according to the present invention;

- figure 16 is a partly cut-away perspective view of a further embodiment according to the invention;

- figure 17 is a perspective view of a detail of the embodiment of figure 16;

- figure 18 is a perspective view of a further embodiment according to the present invention; - figure 19 is a perspective view of a further embodiment according to the present invention;

- figure 20 is a perspective view of a further embodiment according to the present invention; - figure 21 is a perspective view of a further embodiment according to the present invention.

In an embodiment (fig. 1) according to the present invention, four ribs 4,5,6,7 are mutually connected in crosswise manner. This crosswise connection will be referred to in the following as a sliding cross. The sliding cross comprises two double pivot parts 14,15.

Double pivot part 15 comprises side wall 27, upper wall 28 and side wall 29. Ribs 5,7 are fixed thereto by means of pins 141,142. Sliding pivot part 14 comprises side walls 22,24 and upper wall 23. Ribs 4,6 are mounted pivotally by means of pins 25,26. Sliding pivot part 14 further comprises bush 17 for distributing frictional forces which result during sliding of sliding part 14 over rib 7. Rib 7 is further covered with a friction-reducing layer such as for instance Teflon, whereby the friction between bush 17 and arm 7 is greatly decreased.

As can be seen in figure 2, the sliding cross is applied in for instance rectangular tent-cloth panels. Ribs or arms 4,5,6,7 are herein longer than the diagonals of the periphery of the cloth. Ribs 4,5,6,7 are herein pressed under tension against the cloth in the situation of tent-cloth panel 3 in figure 2. In an application of a sliding cross according to the present invention a tent-cloth is bent slightly and placed under a slight tension by folding open all arms, whereafter sliding part 14 and two associated arms are slid round a rib to the centre and just a little beyond it (for instance 7 to 10 percent) , whereby the periphery of the polygon (a quadrilateral in figure 2) is tensioned and the cloth is tensioned by an increased curvature of the ribs .

In a cloth panel 3 (fig. 2) a rectangular cloth 12 is stretched by two frame parts 1,2 placed crosswise. These bent poles 1,2 comprise ribs 4,5,6,7. Bands 8,9,10 and 11 are stitched along the edges of cloth 12. These bands 8,9,10,11 are fixed on the outer ends 18,19,20,21 of ribs 4,5,6,7. Because the rods 1,2 consisting of ribs 5,7 and 6,4 are longer than the diagonals of rectangle 8,9,10,11, the poles 1,2 are bent in the direction of the cloth by means of pressing pole 2 respectively ribs 4,6 through just further than the centre of pole 1. Due to this arc and the tension on the ribs and thereby on the cloth, a very rigid construction of the cloth panel is created, which can be folded up and transported in the folded state in very simple manner. Folding up of panel 3 takes place by moving pivot joint 14 in the direction of arrow A. This joint, and therewith ribs 4,6, are herein forced through a "dead point". In the position in figure 2 the framework has stability because pivot joint 14 is situated slightly beyond the centre of tube 1 in the direction of corner point 19.

This is for instance a position situated for instance 7 to 10 percent of the diagonal length from the centre. By now displacing this joint 14 in the direction of arrow A in the direction of a stop 16 this tension is relieved, as shown in figure 3, and joints 14 and 15 can be folded up as shown in figure 4. This results in a package with a length which is roughly half the length of the diagonals.

Folding out of the ribs takes place in order to obtain a stretched cloth in reverse direction, so that a cloth panel can be erected very rapidly in simple manner . Using two such tent panels which are fastened to each other on one side, an A-shaped tent (not shown) can be made in very simple manner, which tent can be easily erected by one person and can serve as work tent, for instance on the public highway.

In a further embodiment (fig. 5) two of the above described sliding crosses are applied. In this embodiment however, two ribs of two different crosses overlap each other. The tent-cloth 52 of this embodiment comprises seven corners and three surfaces. Two surfaces each have three corner points which are stretched by three points of a cross. For the cross with poles 41,42 these are corner points 53,54,55 and, for the surface which has to be stretched by cross 31,32, the corner points 57,58,59. Corner points 56,57 are stretched by ribs 56 and 57 of crosses of opposite cloth parts. This results in triangular roof surface 55,56,57. Owing to this construction a more spacious (work) tent is created using two crosses than the above mentioned A-shaped tent. Such a tent can also be erected very rapidly and simply and can be transported in compact manner through being able to fold up both the crosses. Through the use of the crosses, relatively large tent sizes are also possible in this embodiment owing to the great tensioning of the tent-cloth made possible by the tension built up by the sliding crosses, as elucidated above.

Since two such crosses move apart due to bending force in the ribs, it is necessary to mutually connect at least two of the corner points. In the embodiment corner points 54 and 58 are connected by means of a threshold 44. Threshold 44 can be embodied very simply by means of for instance a wire.

In a further embodiment (fig. 6) the points of two crosses positioned against each other overlap in similar manner as in the embodiment of figure 5. In this embodiment however, two corner points are overlapped per two crosses. This affords several particular advantages. A stable tent is formed per se by applying the sliding crosses. Such a screen can be erected very simply and rapidly. By applying a threshold or tensioning wire 64 it is however also possible to further increase the tension on the cloth, thereby increasing the stability. Tent 60.in figure 6 is embodied with overlapping crosses 65,66,67. The crosses are fixed to cloth 68 at the outer ends. The tent is further provided with a threshold or for instance tensioning wire 64 which pulls together the ends 61A, 61D of the ribs of respective crosses 65,66. The whole is hereby under tension and this provides the tent with sturdiness.

The crosses 65A, 66A, 67A are embodied as the above described sliding crosses or fourfold fold-out hinges. Like sliding crosses, such fold-out hinges can fold up in the direction of the outside of the tent, or in the direction of the cloth.

In this embodiment the crosses are likewise bent in the direction substantially perpendicular to the node. Due to the tension on the periphery of the cloth, wherein the cloth is preferably strengthened using for instance stitched-on bands, the ribs of the rectangles of the tent are substantially straight. The large surfaces 61A, 61B, 63B, 64A; 62A, 62B, 62C, 62D and 61D, 61C, 63C, 63D are bulged outward and brought under tension by the bending of the crosses. This results in bulged rectangles. Both the smaller surfaces

62A, 62B, 63B, 63A and 62C, 62D, 63D, 63C are stretched tight by the bending force of the ribs fixed on the respective corner points. Substantially flat transition rectangles are hereby created between the side surfaces and the upper surface of the tent. Such a tent can be erected very rapidly and take a relatively large form due to the intrinsic stability of the construction, wherein the simplicity of erection remains.

The front side and the rear side of the tent can be equipped with cloth walls or doors and the like.

Figure 6A shows a top view of tent 60 wherein the threshold 64 is released and the cloth panels are folded out. Clearly shown hereby is how the crosses overlap each other, and also shown is that corner points 65A, 66A are provided with sliding crosses, wherein the small parallel dashes indicate the sliding direction of the above described sliding parts of the sliding cross.

Such a screen is very useful in situations where a strong visual screening is desired quickly, such as for instance at accident or disaster locations.

A further tent (fig. 7) comprises four panels as in the embodiment of figures 2-4, which are all fixed to each other at a point 71. These rectangles are further fixed to each along both the sides ending in point 71, whereby the four surfaces 72,73,74,75 form a dome-like tent. Owing to the tension applied to the cloth by respective sliding crosses 76,77,78,79, there results a very stable construction. This construction can be strengthened still further by mutually connecting corner points 76a, 77a, 78a, 79a by means of thresholds or tensioning cords. The position of corner points 76a, 77a, 78a, 79a can hereby be mutually fixed on the one hand and the tension on tent construction 70 as a whole can be increased on the other by shortening the thresholds or cords.

A further embodiment according to the present invention 80 (fig. 8) is provided with more arms or ribs, whereby a cloth panel 88 obtains more points. Three ribs 83,84,87 are connected at one end to joint 81 comprising pivot pins 103,104,106. Also in this embodiment a band is fixed along edges 96; 97, 95; 97, 94; 95, 93; 94 and 96; 93 to the cloth which is held under tension by the ribs, whereby the ribs are slightly curved. Ribs 85,86 are mounted pivotally on sliding part 82 by means of panel 101,102. Sliding part 82 can slide over rib 87 in similar manner as the sliding part of figure 1 over a rib sliding area. Because sliding part 82 slides slightly over a dead point, the ribs 85,86 lie at an angle which is slightly smaller than 180 degrees, wherein rib 87 largely divides this angle in two. The angle between ribs 85,86 on the side of joint 81 is of course slightly greater than 180 degrees.

The folding-up of cloth panel 80 is shown in figures 8, 9, 10, 11 and 12. The cloth panel is shown in fully stretched state in figure 8. Figure 9 shows how sliding part 82 is slid along rib 87 together with ribs 85,86 in order to remove a large part of the tension on the cloth. In this position the ribs 85,86 are straight. Ribs 83,84,87 are here still situated in a state of some tension. In figure 10 the ribs 83,84,87 are folded back relative to joint 81, whereby the whole can be folded up. After the ribs 83,84,87 have been folded back, figure 11 shows that through loosening of the cloth the ribs 85,86 can be folded back after sliding part 82 has been slid back in the direction of joint 81. All ribs can then be folded toward each other whereby cloth panel 80 comes to lie in fully folded-up state as shown in figure 12.

A further embodiment is cloth panel 90 (fig. 13) . This cloth panel comprises on a joint 91 four ribs and a sliding part 92, to which two ribs are fixed. The operation of this embodiment is analogous to the operation of cloth panel 80. A support pole 93 is further fixed to cloth panel 90. This pole is mounted on joint 91. Using this pole 93 the cloth panel can be placed or held fixedly in desired position.

A further cloth panel 94 is embodied in similar manner to cloth panel 90. Rib 95 here however takes a heavier form, whereby a pole 96 can be mounted on the end thereof. A further cloth panel 97 is embodied as cloth panel 90 with a stronger rib 95 than in cloth panel 94. This embodiment is for instance suitable for placing against an outer wall, whereafter work can be carried out under the cloth panel, wherein the work to be carried out and personnel carrying out the work are sheltered from for instance precipitation such as rain or wind. By varying the length of pole 96 or embodying thereof with multiple legs, workpieces can be screened at different working heights. Possible additional legs can improve the standing firmness.

In tent 160 (fig. 16) four cloth panels 80 are fixed to each other in order to obtain a substantially dome-shaped tent. It is possible herein to manufacture the cloths of the different panels from one cloth. The tension applied to the cloth by making use of the sliding crosses of panels 80 is in principle to provide the tent with sufficient strength. It is however still possible to apply thresholds 161 in order to increase the tension in the whole. It is further possible to close off the remaining openings 0 with cloth parts which can for instance acquire the functionality of doors or wind guards. Using this embodiment tent constructions are possible which are very spacious and which can be erected very rapidly.

A detail of the frame of tent 160 is shown in fig. 17. The ribs of two cloth panels 80 are shown here, as well as three pieces of tensioning band 171,172,173 which are fixed along the sides of the cloth, which tensioning band pieces absorb the forces along the edges of the cloth exerted by the ribs of the cloth panels.

Figures 18-21 show four embodiments for fixing to the poles the cloths with the tensioning bands arranged along the periphery of the cloth.

Figure 18 shows corner part 180, wherein rib 181 is fixed to tensioning bands 183 by means of corner fixing part 182. Cloth 184 is stitched to tensioning bands 183. Because the corner of cloth 184 is not connected to rib 181, damage to the cloth is avoided.

A corner point 190 is provided with a rib 191, to which is fixed ring 192. This ring 192 is in turn fixed to tensioning band 193 onto which the cloth 194 is stitched. In a further embodiment of a higher point, a rib 201 is provided with conical end part 202. A tensioning band 203 is wound at least once and optionally for instance glued round this conical part. Cloth 204 is herein also stitched onto tensioning band 203. If use is made of larger cloths which form a tent by means of a plurality of tensioning frames, it is important that the cloth can be tension-free at the corner points. Points of ribs must for instance be prevented from damaging the cloth at that position. A corner point 210 is provided for this purpose with spacers 211,212,213 to which tensioning bands 217 are attached. These wire parts 211,212,213 are fixed to each other by means of wire parts 214,215,216. Three tensioning bands and two ribs 218 are present at this corner point. The ribs present are fixed to wire parts 214,215,216. In this embodiment this takes place by feeding wire parts 214,215 through eyes of end parts 219 of the ribs. A corner point 210 can be embodied in similar manner as a corner part with a plurality of tensioning bands 217 and optionally a plurality of ribs 219, subject to the tent design and the applied cloth panels .

The present invention is not limited to the above described preferred embodiments; the rights sought are defined by the following claims.

Claims

1. Assembly of a frame and cloth to be stretched thereon, comprising:

- at least one second frame part comprising at least one second arm,

- wherein the first pivot member of the first arms is slidable along a second arm.

2. Assembly as claimed in claim 1, wherein the second frame part comprises a second pivot member for pivoting two or more second arms.

3. Assembly as claimed in claim 1 or 2, wherein the outer ends of the arms are connected to corner points of at least one cloth in order to stretch the cloth using the frame.

4. Assembly as claimed in one or more of the foregoing claims, wherein the arms are longer and/or the sum of two arms together lying substantially mutually in line is longer than half a diagonal of the cloth.

5. Assembly as claimed in one or more of the foregoing claims, wherein the arms are rods which are to at least some extent flexible.

6. Assembly as claimed in claim 5, wherein the rods comprise fibre glass.

7. Assembly as claimed in one or more of the foregoing claims, wherein the cloth has a substantially non-stretching periphery.

8. Assembly as claimed in one or more of the foregoing claims, wherein the corner joints between the arms and the cloth absorb forces without stretching the cloth along the edges.

9. Assembly as claimed in one or more of the foregoing claims, wherein the cloth is strengthened along the edges thereof with strengthening means.

10. Assembly as claimed in one or more of the foregoing claims, wherein the first and/or second pivot members comprise a pivot means for each arm connected thereto.

11. Assembly as claimed in claim 10, wherein the pivot means comprises a shaft.

12. Assembly as claimed in one or more of the foregoing claims, wherein the second arm, along which the first pivot member slides, comprises a covering with a low friction.

13. Assembly as claimed in one or more of the foregoing claims, wherein the first pivot member comprises a sliding member which encloses the first arm along which the first pivot member slides, and this part is sufficiently long to distribute the frictional forces over a relatively large surface area.

14. Assembly as claimed in one or more of the foregoing claims, wherein the first pivot member further comprises an engaging part for guiding thereof along the second arm.

15. Assembly as claimed in one or more of the foregoing claims, wherein the first pivot member is slidable along the second arm further than halfway along the diagonal or arcuate diagonal extending substantially along this arm.

16. Assembly as claimed in one or more of the foregoing claims, wherein the smallest angle between two frame parts lies in the interval of 35-90 degrees.

17. Assembly as claimed in one or more of the foregoing claims, comprising four arms with a relative length ratio such that a quadrilateral assembly is substantially rectangular, as seen from a point perpendicularly of the node of the arms.

18. Assembly as claimed in one or more of the foregoing claims, comprising four arms with a relative length ratio such that a quadrilateral assembly is substantially kite-shaped, as seen from a point perpendicularly of the node of the arms .

19. Assembly as claimed in one or more of the foregoing claims, wherein the bending of the arms due to the stretching is up to 15 percent of the diagonal length.

20. Assembly as claimed in one or more of the foregoing claims, comprising at least two frame parts, which each comprise a first frame part and a second frame part, wherein the pairs of frame parts mutually overlap in that at least one pair of two arms are arranged crossing each other.

21. Assembly as claimed in one or more of the foregoing claims, wherein two corner points of the assembly are mutually connected such that these points are pulled toward each other.

22. Tent comprising at least one assembly as claimed in one or more of the claims 1-21.

23. Screen comprising at least one assembly as claimed in one or more of the claims 1-21.

24. Fixing member for fixing a cloth or cloth reinforcement to an arm, comprising:

- at least two fixing eyes for fixing the cloth or the cloth reinforcement thereto, - at least one connecting part for connecting the fixing eyes, and

- fastening means for fastening the fixing member to the arm.

25. Fixing member for fixing a cloth or cloth reinforcement to an arm, comprising: - an annular member for fixing the cloth or the cloth reinforcement thereto,

- fastening means for fastening the fixing member to the arm.

26. Fixing member for fixing a cloth or cloth reinforcement to an arm, comprising:

- a conical member for fixing the cloth or the cloth reinforcement thereto, - wherein this conical member is arranged on the arm close to the end thereof.

27. Fixing member for coupling at least two arms and at least two cloth reinforcements to each other, comprising : - one eye per cloth reinforcement for fastening the cloth reinforcement to the fixing member,

- one coupling part per eye for fastening the eye to another eye,

- fastening means per arm for fastening the arm to a coupling part.

28. Assembly comprising at least two overlapping frame parts, each comprising at least arms and cloth for stretching thereon, further comprising:

- pivot means for holding together and pivoting the arms per frame part,

- wherein the frame parts are flexible, and

- wherein the cloth can be stretched by means of tensioning means and/or the arms of the frame parts.

29. Method for stretching a polygonal cloth, comprising the following steps of:

- partly folding out at least three arms which form part of at least two frame parts,

- forming at least one frame part using these arms which comprises at least an arm along at least one diagonal or perpendical line of a polygonal cloth, - sliding a pivot member along one of the arms along the diagonal or perpendical line in order to force all arms under tension against the cloth.