FLEXIBLE CONTAINER COMPRISING SEVERAL LIFTING MEANS

Abstract: The present invention relates to a flexible intermediate bulk container with multiple lifting means. Said container comprising at least two lifting loops (3, 15) which are integral extensions (2, 10, 15) of a side wall structure and a base structure (4). Said extensions (2, 10, 15) are folded and joined to adjacent side wall panels such that each lifting loop (3, 15) connects with or are integral parts of two or three side wall panels and all fibers of the lifting loops (3, 15) have the same lifting height. The wall structure can have double layer walls (16, 17) such that each lifting loop (15) is connected to or integral with both layers and the ends of each lifting loop (15) are displaced, one from another. Both wall structure and lifting loops (3, 15) can have integrally woven or stitched reinforcing bands. Said container can have upper closing means comprising top lid (19), filling spout (20) and a wall structure (18) with an open lower end.

Description: Flexible container comprising several lifting means This invention relates to flexible intermediate bulk contain (FIBC) used in the storage and transport of bulk products in granular, powder or paste forms. Said FIBCs having integral lifting means, i.e. the lifting means are extensions of the side wall structure. The total width of all lifting means constitutes at least 25 % of the FIBC circumference and at least 50 % of the longitudinal fibres of the wall structure are directly engaged when it is lifted. Generally speaking are FIBCs manufactured from at least one piece of woven fabric, particularly woven poly-propylene or other suitable synthetic material and required to carry loads of 500 kgs or more with a considerable safety margin. Several proposals for the construction of such FIBCs are known. Typical commom features are: a side wall structure, made up from one or more panels of woven fabric stitched up to form a tube or from a piece of tubular fabric eliminating side seams. a base construction closing the lower -open end of the lifting mean(s) at the upper end of the side wall struc¬ ture capable of taking the load when the lifting mean(s) are engaged with suitable lifting mechanisms like hooks or tines of a fork lift truck. and frequently closing means at the upper end of the side wall structure in the form of a lid of flexible product, stitched to the upper circumference of the wall structure. The lid can be equipped with a filling spout of flexible material. The lifting means can be separate lifting loops stitched on to the side wall structure or be formed by integral extentions of the side wall structure. In the applicants GB patent no. 1.475.019 the combined width of the two lifting loops corresponds to 50 % of the FIBC circumference, i.e. all longitudinal fibres of the wall structure are engaged when it is lifted. FIBCs in accordance with above patent have proved to be very successful for the storage and transport of numerous bulk products. A major reason for the success has been the simple construction and the high lifting capacity. However, the use of said FIBCs have also hade their restrictions, especially when applied in areas with restricted overhead clearance e.g. loading in closed containers or railway wagons, as the total height when lifted is too large compared with fill height of the contained product. For FIBCs having four lifting loops sewn onto the wall struc¬ ture, restricted overhead clearance does not constitute a problem. SUBSTITUTE SHEET FIBCs having two tunnel shaped lifting loops, sewn on or integral with the wall structure, are also known. From GB patent no. 1,549,448 a FIBC having two tunnel shaped lifting loops, which are sewn onto two adjacent sides of the wall structure engaging only 50 % of the longitudinal fibres of the wall structure when the FIBC is lifted, is known. Further it is known from US patent no. 4,300,608 to use two lifting loops which are integral parts of two opposing sides of the wall structure, again only 50 % of the side wall structure circumference is engaged when the FIBC is lifted. In this respect the two embodiments are identical. The latter, however, have the advantage of upraised and opened lifting loops due to-the inserts of the lifting loops, making engage¬ ment with suitable lifting mechanisms, especially the tines of a fork lift truck, easy. As the inserts are separate pieces this solution will be more expensive. The applicants EP patent no. 0,050,845 relates to a FIBC manufactured from two or four panels of woven fabric which, when stitched together, formes a FIBC with a single or double layer base and four integral lifting loops. The lifting means are direct extensions of said panels constituting the wall structure. Their combined width corresponds to 50 % of the circumference, thus all longitudinal fibres are engaged when the FIBC is lifted. FIBC according to above EP-patent permits handling in areas with restricted overhead clearance but the lifting capacity is reduced due to hoop stress concentrations at the top center of each of the four wall panels. Another disadvantage of SUBSTITUTE SHEET these FIBCs is the apparent distortion of the lifting loops making direct engagement with normal lifting mechanisms difficult. For example will a fork lift truck driver need a helper to engage the tines into the lifting loops, adding costs to every handling operation. Both disadvantages can to some extent be reduced by increasing the length of the lifting loops, but then the requirement for overhead clearance incre¬ ases. This type of FIBC constitutes an obvious compromise and its use will therefore be restricted. In the continued research and development work with this type of FIBCs, i.e. FIBCs having low lifting heights and a plurality of integral lifting loops, the inventors tried to meet the needs for improved lifting capacity, reliability and ease of handling. The main object of the present invention is to provide an improved FIBC with lifting loops preferably two or four, which can easily be engaged by suitable lifting mechanisms, especially the tines of a fork lift truck and at the same time meet the requirements for easy handling in areas with restricted overhead clearance and having a high lifting capacity. Another object is to reduce the difference between total height when lifted and the fill height of contained product to permit stacking in areas with restricted overhead clearance increasing the transport capacity of closed vehicles and containers. A further object is to permit filling of the FIBC whilst hanging by its lifting loops only, e.g. hanging on the tines of a fork lift truck. SUBSTITUTE SHEET To meet the above objects the inventors had to find ways to reduce, or compensate for the influence of the hoop stress concentrations at the top center of each of the four wall panels. There are two reasons for build up of hoop stress: a. The horizontal load component, viewed perpendicular to the wall panels, results in hoop stress as each part load from each lifting loop is not at the wall panel center. Thus the longer the lifting loops, the smaller the angle and the smaller will the hoop stress component be. b. A pure geometrical problem, due to the width of the liftin loop, which can be up to 1/4 of the FIBC circumference. In a FIBC according to above EP patent the extension of one wall panel is split in two halves, each to form a lifting loop and half of an adjacent wall panel. The edge of a lifting loop reaching from the top center of a wall panel to the top center of an adjacent wall panel will then have a shorter lifting height than the other edge of the lifting loop, which reaches to and from the upper corner between the two wall panels. The inner edge of the lifting loop will therefore take the higher load when the FIBC is lifted on fork lift truck tines. The inventors now found that if each half of said wall exten¬ sion was rotated such that one edge would reach from the top center of one side wall panel to the corner of the same side SUBSTITUTE SHEET wall panel and the other edge would reach from the same corner to the top center of the other adjacent side wall panel before stitching up the corner seam of the wall structure, the lifting height of both edges of the lifting loops would be equalized. Not only are both edges of the lifting loops equalized but all fibres in between are equalized and the lifting capacity of the modified FIBC increases. This implies that all fibres in the longitudinal direction of thee lifting loops have substantially the same lifting height in the unstressed mode. Another surprising effect of this modification of the basic construction of FIBCs in accordance with this EP patent is that the apparent distortion of lifting loops disappears, making direct engagement of the lifting loops by the tines of a fork lift truck easy. However, the remaining hoop stress at the top center of each side wall panel was still considerable due to the loads in the lifting loops being off center and the lifting capacity of the FIBC was therefore limited. Increasing the length of the extensions of the wall structure forming the lifting loops would reduce the hoop stress, but caused an undesirable increase in the FIBC lifting height. It is known in the art to close a FIBC at the top with a lid of woven flexible material stitched to the side wall structure along its upper circumference at the product fill level or above. Said lid can have a filling spout of flexible material in its center. After filling of the FIBC, the filling spout is tied off, preventing product to flow out if the FIBC should top le. SUBSTITUTE SHEET The inventors now found that if they supplied such a lid with a wall structure which has an open lower end, placed it inside the FIBC with the wall structure pointing downwards, a double wall structure was created in the upper part of the FIBC. This arrangement would then permit the outer wall extensions forming the lifting loops to start below the produ fill height, without creating openings in the combined wall structure from which product inside the FIBC would leak out. Thus the length of the lifting loops could be increased, hoop stress in the outer wall structure reduced and the lifting capacity of the FIBC could be increased without increasing its total lifting height. The lid with its inner wall structure can be made of light and inexpensive product as its only function is to keep the bulk product inside the FIBC. The lid with its inner wall structure is fastened to the outer,wall with suitable fastening means, e.g. stitching, glue etc. The positioning of the lid will be at the product fill height or above. The inner wall structure shall overlap the outer wall structure with a suitable margin. The fastening of the inner wall structure to the outer need only be strong enough to keep it in position until the FIBC is filled as the pressure from the contents will press the inner wall structure against the outer wall structure. Preferabley the lid is given a squarish shape with its corners protruding into the openings of the lifting loops, causing the lifting loops to open and stand erect making engagement of suitable lifting mechanisms even easier. SUBSTITUTE SHEET It fhe cuts creating the outer wall extensions on two adjacent side panels are stopped approximately at the area being the top of the lifting loops, each pair of lifting loops will transform into "tunnels" forming two tunnel shaped lifting loops. Normally a uniform load distribution along the wall structure increases the lifting capacity. But the hoop stress concen¬ tration at the top center of each side panel still caused problems on some of the prototypes. Instead of improving the load distribution the inventors therefore tried to relieve the area around the top center of the wall panels of lifting stress to avoid the negative effects of the hoop stress. This was obtained by strengthening sections of the wall fabric on each side of and at some distance from the center of each wall panel. The reinforced sections of the side walls continu¬ ing into and becoming parts of the lifting loops will then take a larger part of the lifting stress than the parts of the side wall and lifting loop fabric consisting of base fabric only. The top center area of the wall panels are then relieved on both lifting and hoop stress and the lifting capacity of the FIBC is increased. Surprisingly the distance between the center of the side walls and the reinforced section of the wall fabric had no significant influence of the lifting capacity. Such reinforcing sections of the base fabric can be achieved by either integrally woven reinforcing bands using conventional weaving techniques, e.g. by inserting two warp threads in the position of one or by simply stitching reinforcing bands onto the base fabric. FIBCs in accordance with the invention can be made in different ways. SUBSTITUTE SHEET A preferred embodiment is made from a single layer fabric which is split along the center from each side to a length corresponding to the height of the sidepanel + approx. the desired length of the lifting loops to construct a FIBC with four lifting loops or + approx. half the desired lifting loop length to construct one with only two lifting loops. The part of the fabric which has not been slit is used to form the base and two opposing side wall panels. An other arrangement is made from two identical pieces, each slit in half at approximately half of its full length. Again, the non-split layers shall form two opposing side wall panels. By rotating each of the split lengths and stitching the corner seams and the seams connecting the two halves of the adjacent side panels, one has formed the same top with two or four lifting loops, but now the lower end of the side wall structur is open. Another preferred construction is particularly based on the use of a tube of circular woven fabric or from suitable panels of flexible fabric stitched together to give the required form. The tube can have reinforcing bands. Along the upper edge of the tube, equidistant slits are made to form integral extensions of the wall structure. Each of the integral extensions are then stitched together in pairs forming integral lifting loops. To form lifting loops having constant lifting height across the width of the loops, the loops can either be sewn together at an angle making the inner edge of the lifting loop longer than the outer, or by rotating one of the extensions half way around its axis before connecting it to its counterpart. SUBSTITUTE SHEET A construction especially suited for high lifting stresses, comprises a side wall structure having an outer wall and an inner wall lying within and closely adjacent to the outer wall, a base closing a lower open end of the side wall struc¬ ture, and a plurality of lifting loops at the upper end of the side wall structure. Each lifting loop having a first end that is connected to or integral with the outer wall and a second end that is connected to or integral with the inner wall. This embodiment of the invention thus constitutes what can be considered a double-walled FIBC closed by a base structure common to the two walls. The first and second ends of each lifting loop may be connected to or integral with the respec¬ tive walls in substantially the same circumferential region of the wall structure. Preferably, however, the first and second ends of each lifting loop are displaced one from the other around the circumference of the FIBC, as overall stress distribution thereby is improved. In a particularly preferred arrangement, four lifting loops are provided, and the circum¬ ferential spacing between the two ends of each lifting loop is substantially equal to the circumferential spacing between adjacent ends of adjacent lifting loops. The scope and characterizing features of the invention are as defined in the attached claims. In order that the invention may be better understood, the manufacture of some embodiments of FIBCs will be described in more detail, by way of example only, with reference to the accompanying drawings. SUBSTITUTE SHEET Fig. 1 shows a blank in the form of a length of flat woven fabric which has been slit at both ends along the center line before it is folded and stitched togethe to form a FIBC with four lifting loops and a single layer base. Fig. 2 shows a blank in the form of a length of flat woven fabric which has been slit at one end along its center line before it, together with an identical blank, is folded and stitched together to form the top bf a FIBC with two tunnel shaped lifting loops and an open bottom end of the wall structure. Fig. 3 shows a perspective view of the FIBC with four liftin loops made from the blank of fig. 1. Fig. 4 shows a perspective view of a blank in the form of a length of tubular woven fabric which has been slit at the top to form eight integral extensions of the wall structure before the eight extensions are stitched together to form the top of a FIBC with four lifting loops. Fig. 5 shows a perspective view of a blank in the form of a length of tubular woven fabric which has been cut at the central region along the cutting lines 12. Fig. 6 is a cross section at the central region of fig. 5 after the panels 13 have been folded and stitched onto the lifting loops. SUBSTITUTE SHEET Fig. 7 shows a perspective view of a FIBC with four lifting loops with a double wall structure which is open at its lower end. Fig. 8 shows a perspective view of a top closure with filling spout and a wall structure which is open at its lower end. Fig. 1 shows length of flat woven fabric 1 which has been slit along the middle from both ends to form the four integral extensions 2 (2a, 2b, 2c and 2d) , each representing a lifting loop 3 (3a, 3b, 3c and 3d) and one half of two opposing side panels, the hatched center area 4 of the fabric represents the base of the FIBC. The integral extensions 2a and 2b are now folded and rotated connecting the corners 5a, 5b, 5c and 5d with the corresponding points 5a, 5b, 5c and 5d along the edge of base fabric and stitched togehter with the common seam 6b thereby forming one side panel. The next step is to fold the integral extensi¬ ons 2c and 2d and connecting the corners 5e, 5f, 5g and 5h along the other edge of the base fabric and stitch up the common seam 6e to form another sidepanel opposite to the first. The base is then closed sewing the base seams from 5a to 5d and 5e to 5h. The last step to close the wall structure implies stitching up the corner seams 6a, 6c, 6d and 6f. The result is a FIBC with four integral lifting loops and a wall structure with four side wall panels closed at its lower end with a single layer fabric. SUBSTITUTE SHEET To form a FIBC with only two lifting loops one has to reduce the length of the cuts 8a and 8b to the vicinity of the top of the lifting loops marked by their center lines 7 (7a and 7b) . The FIBC can also be constructed with a double layer base by extending the integral extensions 2a - 2d. The length of the extensions shall correspond to half the width of the base. The double base is formed by joining the extensions either inside or outside the FIBC. The FIBC constructed from the single length of fabric in fig. 1, shown in a perspective view in fig. 3, has four, alternatively two, lifting loops which are easily engaged by the tines of a fork lift truck, have reduced lifting height and can be filled whilst supported by its lifting loops only. The FIBC can also be made from two identical lengths of flat woven fabric as shown in fig. 2 where the cut 8a has been reduced to make a FIBC with only two lifting loops. Each length of fabric constitutes one full side wall panel and two halves of the adjacent side wall panels when formed in the same manner as described for fig. 1, but this FIBC will be open at the lower end of the wall structure. The FIBC may then be completed by adding to it a suitable base structure. In its simplest form the base can take the form of a separate cut piece of fabric simply stitched to the lower ends of the wall structure. The cut length of circular woven fabric in fig. 4 has been slit at the top at eight equidistant places around the circum¬ ference. The cuts 9 forms eight integral extensions 10a - lOh each having upper end corners a and b. SUBSTITUTE SHEET By folding and rotating the extensions in pairs, matching corner a with corner b and corner b with corner a of adjacent extensions, e.g. 10a and 10b and join them with the seams 11, four lifting loops, identical to 3a - 3d of fig. 3 except for their joining seam, are formed. The construction thus achieved comprises a side wall structure with four lifting loops being integral extensions of the side wall structure having a joining seam at their top end and is identical to the construction shown in fig. 3 except there are no side seams (6a - 6f) and the wall structure is open at its lower end. As indicated on fig. 4 the integral extensions 10a - lOh can be cut at an angle with the principal axis. By folding the extensions in pairs matching corner a with corner a and corner b' with corner b' of adjacent extensions, e.g. 10a and 10b and join them with the seams 11, four lifting loops are formed, Due to the angle of the top cut of each extension both edges of the lifting loops and all fibres in between are equalized to the same lifting height. It is obvious that the same affect can be obtained without cutting the extensions 10a - lOh at an angle as long as the seam 11 forms an angle with the principle axis. In that case the two joined extensions will form overlaps at said angle. The cut blank of Fig. 4 have been made up from a tube of circular woven fabric. It isi of course possible to make such blanks from one or more pieces of flat woven fabric by joining two or more edges with seams and thus create a tube. SUBSTITUTE SHEET The cut blanks of Fig. 4 have been illustrated with all cuts being of equal length creating FIBC tops with four lifting loops. However, by reducing the central cut on any two opposin side panels to approximately half their length, the top of a FIBC with only two lifting loops is formed. Due to absence of tensile hoop stress at the four upper corner of the wall structure, the length of these cuts can be reduced maintaining the lifting capacity of the construction. The forming of the lifting loops have been illustrated using the preferred arrangement of the integral extensions having equal length. However, it is within the scope of the invention to have said extensions of different lengths as long as the sum of each pair of extensions which are joined together is the same. It is also possible to construct the top of the FIBC when only two opposing side panels have integral extensi¬ ons and connect the ends of these extensions to adjacent side panels of the wall structure, somewhere between its upper and lower ends. If joined at the lower end, the wall structure will comprise two side panels with double layers and two side wall panels with a single layer. Elongating the extensions still further, they can be joined together below the lower end of the wall structure and even form a single layer base construction. Figure 5 shows a blank in the form of a length of tubular woven fabric. Optionally the fabric can have reinforcing bands (not shown on the drawing) woven integrally with or connected to the base fabric extending parallel to the axis of the tube. To form lifting loops the tube is cut longi- SUBSTITUTE SHEET tudinally in the central region at equidistant places and between adjacent reinforcing bands when such bands are used. One may also cut four panels of the base fabric along three edges 12 to form flaps 13, which are folded along their uncut edge and joined to the uncut parts of the tube with the seams 14. Fig. 6 shows a cross-section of the sentral region of the tube after folding and joining of the flaps, the flaps having the same width as the uncut parts of the tube, which eventually will become the lifting loops 15. The flaps can for example be cut wider than the lifting loops and be wrapped several times around the lifting loops before joined to the lifting loops by suitable means like glue, seam etc. , the result being narrower lifting loops. The reinforcing bands can have the same width or be narrower than the width of the lifting loops. The next step is to take hold of one end of the length or tubular fabric and to turn this inside out and draw it into and through the remainder of the fabric to form a double- walled tube, then effectively folding the fabric around the center parts of the uncut sections that will form the lifting loops 15. The tube then constitutes a side wall structure having an inner wall 16 and an outer wall 17. Either during the folding operation or after, the inner wall is rotated through e.g. 45° relative to the outer wall to arrive at the structure shown in fig. 7. It will be seen that this action displaces the first and second ends of each lifting loop from another by 4 5o around the circumference of the wall structure, and that circumferential spacing between adjacent ends of adjacent lifting loops is also 45°. The amount of SUBSTITUTE SHEET rotation is free but must be minimum equivalent to the width of the lifting loops to also impart a 180° rotation of each loop to equalize the lifting height of both edges of the lifting loops and all other fibers in between the same. Having achieved the structure shown in fig. 7, the FIBC may then be finished by adding to it a suitable base structure and possibl a suitable top structure e.g. of the type shown in fig. 8. The base may be formed by extensions of the fabric of either the inner wall, the outer wall or both walls, the extensions being suitable cut, folded and stitched to form a base of the required shape or by simply stitching a separate cut piece of fabric to the lower ends of the two walls. In the preferred arrangement, the tube of fig. 5 is folded and rotated in such a way that the folded flaps are forming a protective layer of fabric inside the lifting loops protect¬ ing the loadcarrying fibers of the lifting loops from wear in accordance with the applicants EP patent application no. 84102.195,9. According to above patent application the flaps 13 can also be used to form protective sleeves for the lifting loops. FIBCs according to the invention may be open or closed by a cut piece of fabric stitched around the upper part of the side wall structure said piece of fabric having any suitable opening through which the FIBC can be filled. However, as it is an object of the invention to reduce the height of the lifting loops above the product fill height, a better arrangement is to fit the top fabric with a wall structure of approximately the same girth diameter as the SUBSTITUTE SHEET FIBC and which has an open lower end. The top structure shown in fig. 8 is made from a length of tubular woven piece of fabric 18 which at the top has been cut to form four flaps (19a - 19d) which are joined together with seams or other suitable means to form a single layer top of squarish form. In the center is fitted a tubular piece of fabric 20 which will serve as filling chute and which can be closed by tying off with string etc. It will be appreciated that this top structure also can be stitched together from several panels of fabric giving it the same principal shape as that of fig. 8. The top structure of fig. 8 can be placed inside any FIBC according to the invention, and any other FIBC when it is appropriate to close its upper end of the side wall structure, with its lower open end below the deepest cut in the side wall structure of said FIBC. This effectively seals off any cut opening of the arrangement through which product otherwise can flow when the fill height of the product in the FIBC is raised to its maximum, i.e. above the deepest cut opening in the wall structure. In a preferred arrangement the top construction of Fig. 8 is placed inside the FIBC shown on Fig. 3 in such a way that the corners 21 fit the openings 22 of the lifting loops 3a - 3d pressing them open to make engagement of lifting mechanisms even easier. The FIBCs shown in the figures in accordance with the invention are basically of preferred form and arrangement. However, it will be understood that FIBCs may be made in other ways, e.g. the FIBC with double walls, manufactured from a single SUBSTITUTE SHEET length of tubular woven fabric, may also be construed from two similar sections of tubular fabric, each having been cut at one end to form upstanding integral extensions. One such length of fabric is then drawn into the other length of fabri with a minimum displacement corresponding to the width of the extensions, e.g. 45° between the two lengths. The free end of each upstanding extension of the resulting outer wall structure is then sewn onto the free end of the adjacent upstanding extension of inner wall structure. In other arrang ments the inner and outer wall structures may be formed from suitable panels of fabric stitched together to give the required construction. The examples described is of a FIBC having two or four lifting loops, but it will be appreciated that the invention can be applied to a FIBC having any even number of loops, and that when formed from a fabric having interwoven or stitched on reinforcing bands, those bands will be located according to the number of the loops. Other modifications will be apparent to those skilled in the art. The FIBC of the invention can be equipped with protective sleeve(s) as described in the applicants EPO-patent applicatio no. 84102.195,9. By the present invention one has obtained a FIBC with multiple lifting loops having a high lifting capacity as at least fifty per cent of all vertical fibres in the wall structure are engaged to carry the load. The lifting loops of the FIBC have a low lifting height which has been equalized over the full width and can easily be engaged by normal lifting mecha¬ nisms, e.g. the tines of a fork lift truck. One is therefore SUBSTITUTE SHEET independent of special or complicated lifting devices. The FIBC can be filled whilst hanging by its lifting loops only, which together with a square base construction contributes to its square shape. An essential advantage which is obtained by the present invention is that the product in the FIBC can have a fill height above the actual wall structure. This is made possible with the insertion of a top construction, comprising a top lid with filling spout and a wall structure with an open lower end, placed inside the top of the FIBC. The distance between fill height and the top of the lifting loops is thereb considerably reduced. Such. FIBCs can be handled in areas with very small overhead clearance, and when stacked in transport means like closed containers, railway wagons etc. very little space is left unused. The top structure helps the FIBC retain its square shape when stacked for storage and transport. With the present invention one is free to apply a multitude of base constructions, for instance base constructions in accordance with the applicants GB patent no. 1,580,576 and EP patent application no. 84110,404,5. If required, any of the base constructions may be equipped with any suitable spout or other discharge arrangement. SUBSTITUTE SHEET

Claims: Claims 1. A flexible intermediate bulk container (FIBC) comprising at least two lifting loops (3, 15) which are integral extensions of the side wall structure, formed from at least one piece of flexible woven material (1) , said FIBC having a base structure (4) formed from integral parts or extensions of the side wall structure or from separate cut pieces of flexible woven material, said lifting loops (3, 15) having a total combined width of at least 25 % of the wall structure circumference c h a r a c t e r i z e d i n t h a t the integral extensions (2, 10, 15) of two opposite place side wall panels are folded and joined to corresponding parts of their adjacent side wall panels in such a way that each lifting loop (3, 15) thus formed connects with or are integral parts of two or three adjacent side wall panels and that both edges of said lifting loops (3, 15) and all fibres in between have substantially the same lifting height in the unstressed mode. 2. A FIBC according to claim l, c h a r a c t e r i z e d i n t h a t the integral extensions (2) are folded and rotated before joined to the base structure (4) and thus each integral extension (2) forms one half of the two adjacent side panels. SUBSTITUTE SHEET 3. A FIBC according to claim 1, c h a r a c t e r i z e d i n t h a t the integral extensions (10) of two opposing side wall panels are folded and rotated before joined to the corres¬ ponding integral extensions (10) of adjacent side wall panels or alternatively with only two opposing side wall panels having integral extensions (10) , said extensions are folded and rotated before joined to the adjacent side wall panels. 4. A FIBC according to claim 1, c h a r a c t e r i z e d i n t h a t the integral extensions (10) are joined at an angle with the principle axis forming the lifting loops. 5. A FIBC according to claim 4, c h a r a c t e r i z e d i n t h a t the integral extensions (10) of the side wall structure have been cut at an angle at their ends and that the integral extensions (10) of the two opposing side wall panels are folded and joined to the corresponding integral extensions (10) of adjacent side wall panels, connecting shorter edges (a) with shorter edges (a) and longer edges (b) with longer edges (b) , or alternatively with only two opposing side wall panels having integral extensions (10) , said extensions (10) are foled before joined to the upper end of the two adjacent side wall panels such that the shorter edges (a) connect with a corner in the side wall structure. SUBSTITUTE SHEET 6. A FIBC according to claims 1-5, c h a r a c t e r i z e d i n t h a t one pair of opposing side wall panels have a different width to the other pair of opposing side wall panels. 7. A FIBC according to claims 1-6 , c h a r a c t e r i z e d i n t h a t the integral extensions (2, 10) of two opposing side wall panels have only been cut into two halves from their free ends (a, b) to the approximate top (7) of the liftin loops (3) , thus forming only two lifting loops (3) . 8. A FIBC according to claim 1-7, c h a r a c t e r i z e d i n t h a t each side wall panel has at least two reinforcing bands, so placed that at least one reinforcing band runs through each lifting loop (3) and that the reinforcing bands are integrally woven with the base fabric or stitched onto the base fabric. 9. A FIBC according to claim 8 , c h a r a c t e r i z e d i n t h a t the base fabric (1) comprises the reinforcing bands and that each side wall panel has a band of reduced strength in its center. 10. A FIBC according to claims 1-9, c h a r a c t e r i z e d i n t h a t the FIBC is closed by a top structure placed inside the FIBC. Said top structure comprising a top lid (19) with a slit or filling spout (20) and a wall structure (18) of approximately the same girth diameter as the FIBC, SUBSTITUTE SHEET said wall structure (18) being fastened to the FIBC side wall structure by suitable means with its lower open end below the deepest cut in the FIBC side wall structure. 11. A FIBC according to claim 1, c h a r a c t e r i z e d i n t h a t the side wall structure has double layer walls (16, 17) formed from at least one tubular piece of flexible woven material such that each lifting loop (15) is connected to or integral with the fabric of both walls (16, 17) and that the first and second ends of each lifting loop (15) are displaced one from another around the circum¬ ference of the wall structure, a distance which is at least equal to the width of the lifting loops (15), thus both edges of said lifting loops (15) and all fibres in between have the substantially the same lifting height in the unstressed mode. 12. A FIBC according to claim 11, c h a r a c t e r i z e d i n t h a t the inner and outer walls (16, 17) and the lifting loops (15) are all formed from a continuous length of tubular shape having cuts (12) in the central region forming flaps (13) , which, when folded, wrapped around and joined to the uncut parts of the bands connecting each end of the tube, will form multiple layer lifting loops (15) when the tube is folded to form a double-walled side wall structure and then rotating the inner wall (16) relative to the outer wall (17) to displace both ends of the lifting loops (15) . SUBSTITUTE SHEET 13. A FIBC according to claim 12, c h a r a c t e r i z e d i n t h a t two similar tube shaped sections are used, each having been cut at one end to form single or multiple layers integral extensions (15) , forming the FIBC by drawing one length of fabric into the other with a minimum dis¬ placement equivalent to the lifting loop width and joinin the free ends of adjacent extensions to form lifting loops (15) or alternatively that only one of the tube shaped sections have been cut to form said extensions and that the free ends of said extensions from one layer of the side wall structure are joined to the other layer of the side wall structure with a minimum displacement equivalent to the lifting loop width. 14. A FIBC according to claims 11-13, c h a r a c t e r i z e d i n t h a t each side panel layer has at least one reinforcing band so situated that the reinforcing band runs through the uncut layer of the lifting loop (15) and that the rein¬ forcing bands are integrally woven with the base fabric or stitched onto the base fabric. 15. A FIBC according to claims 11-14, c h a r a c t e r i z e d i n t h a t the FIBC is closed by a top structure placed inside the FIBC. Said top structure comprising a top lid (19) with a slit or filling spout (20) and a wall structure (18) of approximately the same girth diameter as the FIBC, said wall structure (18) being fastened to at least the inner FIBC side wall structure by suitable means with its lower open end below the deepest cut in the FIBC side wall structure. SUBSTITUTE SHEET

Inventors: MYKLEBUST EIRIK, RASMUSSEN ODD FREDRIK, MYKLEBUST, EIRIK, RASMUSSEN, ODD, FREDRIK
Applicants: NORSK HYDRO AS, NORSK HYDRO A.S
Application year: 1988
Main classification: B65D88
IPC codes: B65D30, B65D33, B65D88