GB1604442A

GB1604442A - Flexible bulk containers

Info

Publication number: GB1604442A
Application number: GB35664/77A
Authority: GB
Original assignee: Tay Textiles Ltd
Current assignee: Tay Textiles Ltd
Priority date: 1977-08-25
Filing date: 1977-08-25
Publication date: 1981-12-09
Also published as: SE422043B; FI782575A; NO782780L; NO147101C; NO147101B; FI61175B; SE422043C; FI61175C; SE7808970L

Description

(54) IMPROVEMENTS RELATING TO FLEXIBLE BULK CONTAINERS (71) We, TAY TEXTILES LIMITED, a British Company, of Park Mill, Dundee, Scotland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to flexible bulk containers.

Such containers may be used in the storage and transport of materials in granular, powder and other particulate form, such as chemicals, foodstuffs, cement and so forth.

The containers are generally in the form of large bags or sacks. They are often required to carry loads of up to one tonne or more, and there should desirably be a considerable safety margin abobve this working load. The containers are frequently made from woven fabric, for example woven polypropylene or another suitable synthetic material.

To avoid the use of pallets, slings or the like when lifting a bulk container, it may be provided with lifting means such as loops of high strength webbing stitched to the side of the container. The points of attachment of the lifting loops can be regions of high stress concentration, and failure of or damage to the stitching for the loops or the bag material itself, may occur. This may be a particular problem if a container is subjected to rough treatment such as intermittent lifting movements which can result in high transient stresses.

There has been proposed a container in which lifting loops are provided by a fold in material integral with the main body of the container.

According to the invention there is provided a flexible bulk container having sidewalls and a base, the sidewalls comprising two adjacent strip portions of material each having a transverse fold so as to comprise two legs, for each strip portion there being a seam joining the two legs along one edge thereof, and there being seams joining the remaining edges of the legs of one portion and the corresponding remaining edges of the legs of the other portion so as to join the two strip portions together. each seam terminating at a distance from the respective fold whereby two lifting loops are provided by the folded material.

The two strip portions could be completely separate strips, preferably of the same width as each other. In this case the container may be fitted with a separate bottom which may be square or circular depending on whether the finished container is to be square or circular, the bottom being fitted to the ends of the strips remote from the loops. Alternatively, the free ends of the strips may be gathered in and connected together to form the bottom of the container.

Generally speaking, in the above arrangements the strips will be of equal length and will be folded double. In an alternative arrangement one strip is longer than the other, and is folded so that one leg is longer than the other. The additional material thus provides a flap which can be used to form the base of the container. In this arrangement the additional length of material should equal the width of the strips.

Joining of the various strip portion edge portions need not be direct, and intermediate fabric portions, for example in the form of gussets, could be employed. In a preferred embodiment, the two strip portions are parts of a single continuous strip of material, suitably folded and joined. The strip may define an integral base for the container.A container with an integral base may thus comprise a single strip of material, wherein the base of the container is defined by a section of the strip intermediate the ends thereof, whose length is substantially equal to the width of the strip, there being two said strip portions extending on opposite sides of the base, the two legs of one portion being joined together by a seam along one side of the strip, the two legs of the other portion being joined together by a seam along the other side of the strip, the remaining side of one leg of the one portion being joined by a seam to the remaining side of one leg of the other portion, and the remaining side of the other leg of the one portion beingjoined by a seam to the remaining side of the other leg of the other portion.

It will be appreciated that the single continuous strip could, if required, comprise one or more separate strips joined end to end or even laterally prior to the various folding or joining operations.

The lifting loops of a container in accordance with the invention may be formed by material which is the full width of the container, so that lifting stresses are distributed substantially evenly over the material of the container. If required, the various seams, particularly those running from the lifting loops, could be provided with reinforcement.

In the case of woven fabric these seams will generally run along the selvedges of a strip portion, and advantageously these selvedges can be inherently reinforced. Thus in a region adjacent the selvedges there could be a higher density of warp threads or warp threads of higher tenacity.

In the above-described specific example of a container comprising a single strip, if made from woven fabric, such reinforced selvedges are of particular advantage since of six seams, four can be along pairs of selvedges of respective fabric portions, and the remaining two each include one selvedge.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a plan view of single continuous strip of material before folding and joining to make a container in accordance with the invention; Fig. 2 is a plan view showing the first stage in the folding and joining operations; Fig. 3 shows an intermediate stage, in the operation; Fig. 4 shows a further stage in the operation; and Fig. 5 is a perspective view of the completed container.

In Fig. 1 the is shown a strip of woven fabric, for example woven polypropylene, with the warp threads running longitudinally of the strip and the selvedges along the edges thereof.

The opposite ends of the strip are defined by points A and B, and A' and B' respectively. Imaginary lines running transversely between points X and Y, C and D; C' and D'; and X' and Y'; divide the strip into five panels, 1, 2, 3, 4 and 5. Panels 1, 2, 4 and 5 are of equal size, so that the strip is symmetrical about its centre line 00. Panel 3 is as long as the strip is wide, i.e. lengths C' and D--D' are equal to lengths C-D and C'-D.

The opposite ends of the strip are then folded towards each other in the direction of the arrows on Fig. 1, about lines X-Y and X'-Y' respectively, so that point A meets point C; point B meets point D; point A' meets point C'; and point B' meets point D'.

The result is as shown in Fig. 2. There are thus defined two double folded strip portions having legs I and 2; and 4 and 5 respectively, interconnected by a central portion 3.

As shown in Fig. 3, legs 1 and 2 are stitched together along one edge of the strip, from the point B, D to a point E, spaced from the fold line X-Y. Similarly the legs 4 and 5 are stitched together along the other edge of the strip, from the points A', C' to a point E', spaced from the fold line X'-Y'. Stitching is indicated generally as S.

Subsequently point A is moved in the direction of the solid-line arrow on Fig. 3, to meet the point D', and stitching is inserted along the line D-AD', to join the end of leg I to the edge of the central portion 3.

Additionally, point B' is moved in the direction of the dotted-line arrow on Fig. 3, to meet the point C, and stitching is inserted along the line B'C--C'. The resultant position is shown in perspective in Fig. 4.

Finally, the edges X-D'A and Y'D'A are stitched together, as are the edges X--CB' and Y'CB', in each case the stitching extending from the points D'A or CB' to point spaced from the points X and Y' by an amount substantially equal to the distance E-Y or E'-X'. The final container is shown in Fig. 5. As can be seen, the central portion 3 constitutes the base of the container, the legs 1, 2, 4 and 5 constitue the side walls; and the folds interconnecting the legs 1 and 2, and 4 and 5, form two lifting loops 6 and 7.

In use, lifting tackle can be inserted through the loops, and the split 8 between them can be used as a filling opening. To close the container, the loops 6 and 7 could for example be bunched together and tied around.

The resultant container can be very strong, carrying loads of up to one tonne or more, with a safety margin of perhaps five times.

It will be appreciated that in carrying out the specific embodiment, it may not be necessary to perform all the steps in the specific order described herein. Furthermore, in practice the various points referred to may not be in their exact positions, due to the thickness of material, the need to accommodate stitching, etc., Although woven fabric and stitching have been referred to, other materials such as sheet plastic for example could be used, and other joining methods such as riveting or welding.

WHAT WE CLAIM IS:- 1. A flexible bulk container having sidewalls and a base, the sidewalls comprising two adjacent strip portions of material each having a transverse fold so as to comprise two legs, for each strip portion there being a seam joining the two legs along one edge thereof, and there being seams joining the remaining edges of the legs of one portion

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. It will be appreciated that the single continuous strip could, if required, comprise one or more separate strips joined end to end or even laterally prior to the various folding or joining operations. The lifting loops of a container in accordance with the invention may be formed by material which is the full width of the container, so that lifting stresses are distributed substantially evenly over the material of the container. If required, the various seams, particularly those running from the lifting loops, could be provided with reinforcement. In the case of woven fabric these seams will generally run along the selvedges of a strip portion, and advantageously these selvedges can be inherently reinforced. Thus in a region adjacent the selvedges there could be a higher density of warp threads or warp threads of higher tenacity. In the above-described specific example of a container comprising a single strip, if made from woven fabric, such reinforced selvedges are of particular advantage since of six seams, four can be along pairs of selvedges of respective fabric portions, and the remaining two each include one selvedge. An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a plan view of single continuous strip of material before folding and joining to make a container in accordance with the invention; Fig. 2 is a plan view showing the first stage in the folding and joining operations; Fig. 3 shows an intermediate stage, in the operation; Fig. 4 shows a further stage in the operation; and Fig. 5 is a perspective view of the completed container. In Fig. 1 the is shown a strip of woven fabric, for example woven polypropylene, with the warp threads running longitudinally of the strip and the selvedges along the edges thereof. The opposite ends of the strip are defined by points A and B, and A' and B' respectively. Imaginary lines running transversely between points X and Y, C and D; C' and D'; and X' and Y'; divide the strip into five panels, 1, 2, 3, 4 and 5. Panels 1, 2, 4 and 5 are of equal size, so that the strip is symmetrical about its centre line 00. Panel 3 is as long as the strip is wide, i.e. lengths C' and D--D' are equal to lengths C-D and C'-D. The opposite ends of the strip are then folded towards each other in the direction of the arrows on Fig. 1, about lines X-Y and X'-Y' respectively, so that point A meets point C; point B meets point D; point A' meets point C'; and point B' meets point D'. The result is as shown in Fig. 2. There are thus defined two double folded strip portions having legs I and 2; and 4 and 5 respectively, interconnected by a central portion 3. As shown in Fig. 3, legs 1 and 2 are stitched together along one edge of the strip, from the point B, D to a point E, spaced from the fold line X-Y. Similarly the legs 4 and 5 are stitched together along the other edge of the strip, from the points A', C' to a point E', spaced from the fold line X'-Y'. Stitching is indicated generally as S. Subsequently point A is moved in the direction of the solid-line arrow on Fig. 3, to meet the point D', and stitching is inserted along the line D-AD', to join the end of leg I to the edge of the central portion 3. Additionally, point B' is moved in the direction of the dotted-line arrow on Fig. 3, to meet the point C, and stitching is inserted along the line B'C--C'. The resultant position is shown in perspective in Fig. 4. Finally, the edges X-D'A and Y'D'A are stitched together, as are the edges X--CB' and Y'CB', in each case the stitching extending from the points D'A or CB' to point spaced from the points X and Y' by an amount substantially equal to the distance E-Y or E'-X'. The final container is shown in Fig. 5. As can be seen, the central portion 3 constitutes the base of the container, the legs 1, 2, 4 and 5 constitue the side walls; and the folds interconnecting the legs 1 and 2, and 4 and 5, form two lifting loops 6 and 7. In use, lifting tackle can be inserted through the loops, and the split 8 between them can be used as a filling opening. To close the container, the loops 6 and 7 could for example be bunched together and tied around. The resultant container can be very strong, carrying loads of up to one tonne or more, with a safety margin of perhaps five times. It will be appreciated that in carrying out the specific embodiment, it may not be necessary to perform all the steps in the specific order described herein. Furthermore, in practice the various points referred to may not be in their exact positions, due to the thickness of material, the need to accommodate stitching, etc., Although woven fabric and stitching have been referred to, other materials such as sheet plastic for example could be used, and other joining methods such as riveting or welding. WHAT WE CLAIM IS:-

1. A flexible bulk container having sidewalls and a base, the sidewalls comprising two adjacent strip portions of material each having a transverse fold so as to comprise two legs, for each strip portion there being a seam joining the two legs along one edge thereof, and there being seams joining the remaining edges of the legs of one portion

and the corresponding remaining edges of the legs of the other portion, so as to join the two strip portions together, each seam terminating at a distance from the respective fold whereby two lifting loops are provided by the folded material.

2. A container as claimed in claim 1 wherein the strip portions consist of separate strips of material.

3. A container as claimed in claim 2 wherein one strip is longer than the other, and is folded so that one leg is longer than the other, thereby providing a flap forming the base of the container.

4. A container as claimed in claim 1 wherein the strip portions are part of a single continuous strip of material.

5. A container as claimed in claim 4, wherein the strip defines an intergral base for the container.

6. A container as claimed in claim 5 wherein the base of the container is defined by a section of the strip intermediate the ends thereof, whose length is substantially equal to the width of the strip, there being two said strip portions, extending on opposite sides of the base, the two legs of one portion being joined together by a seam along one side of the strip, the two legs of the other portion being joined togehter by a seam along the other side of the strip, the remaining side of one leg of the one portion being joined by a seam to the remaining side of one leg of the other portion, and the remaining side of the other leg of the one portion being joined by a seam to the remaining side of the other leg of the other portion.

7. A container as claimed in claim 6 wherein the free end of the one portion is joined to one edge of the base and the free end of the other portion isjoined to the other edge of the base.

8. A container as claimed in Claim 7 wherein the portions are of equal length.

9. A container as claimed in claim 8 wherein the fold lines bisect their respective portions.

10. A flexible bulk container, substantially as hereinbefore described with reference to the accompanying drawings.