GB2262504A - Bulk container with semi-rigid support member - Google Patents

Abstract

The invention provides a semi-rigid bulk container 1, for use in storing and transporting in particular mortar and mortar- like products. The container comprises a flexible bag 2 of a woven fabric and an associated semi-rigid support member 3 to increase the rigidity of the flexible bag and allow the container to retain when not full substantially the same shape as it would have when full. The invention also provides a semi-rigid support member for use as part of such a container. The support member 3 may take the form of a bag or a box and may fit either inside or outside the flexible bag 2. It may have handles 4 of piano wire stitched to the woven fabric and, where the support member is a tube of semi-rigid material forming four sides of the container, a removable base of plywood and polystyrene sandwich board. The container may alternatively have the form of an open-topped box, with sides tapering slightly outwards and upwards from the base to allow nesting of several containers. <IMAGE>

Description

CONTAINER Field of the Invention This invention relates to a container of the type in the form of a semi-rigid bag, which may be used for the storage and transportation of moist or wet materials such as mortar, and also for the storage and transport of dry powdered materials such as flour, paint pigments, etc. The invention also relates to a support member for use in association with the container.

Backqround to the Invention Bulk containers are known which take the form of a flexible bag, usually made from a woven material. These are used for the storage and transportation of bulk materials, in particular materials in powdered or granular form. The bags are typically provided with lifting handles, by which they can be lifted and carried using e.g. a fork lift truck.

Flexible bulk containers, whilst being convenient for storing and transporting materials, can nevertheless be difficult to fill because, having little rigidity when empty, they are prone to collapse during the filling process. They are particularly difficult to fill with wet products, such as mortar, which have to be piped into them.

In the handling of mortar, this problem is overcome by storing and transporting the mortar in strong, rigid, bath-like containers made from materials such as steel or glass reinforced plastics (GRP). However, such containers are relatively expensive and are extremely attractive to potential thieves. They are also easily damaged, even using (as is the current practice) a protective lining of builder's film to shield the inside of the container from the mortar.

It is therefore an aim of the present invention to provide a bulk container for use in storing and transporting both wet and dry products (including mortar), which overcomes or at least mitigates the above described problems. The container should be sufficiently rigid as not to collapse on filling, but should also be relatively cheap to manufacture and not easily damaged during use.

Statement of the Invention According to the present invention there is provided a semirigid bulk container comprising a flexible bag made of a woven fabric; and an associated support member made from a semirigid material which increases the rigidity of the flexible bag and. allows the container to retain when not full substantially the same shape as it would have when full. The container preferably also comprises one or more lifting handles.

Such a container is relatively simple and inexpensive to manufacture. However, because it has an associated support member to increase its rigidity, it will retain its shape when standing empty and not collapse when it is being filled with a product (such as mortar) to be stored and transported in it.

The container is such as can be used to store and transport a variety of different bulk materials, including dry powdered or granular materials, wet or moist products such as mortar, etc. It is preferably for use in the storage or transportation of mortar or mortar-like products. It will typically have the form of a square or approximately squaresided box, this three-dimensional shape being retained because of the presence of the support member.

The flexible bag is preferably made of a woven fabric of the type conventionally used in the manufacture of flexible bulk containers. This bag will provide the main strength in the container of the present invention, whilst the support member provides its rigidity. The bag may be open at its upper end, or closeable, eg, by means of a draw-string.

The support member may take the form of an inner lining for the flexible bag, and may or may not be detachable therefrom.

Alternatively, the support member may be located outside of the flexible bag in use, again being detachable or not as required.

Where the support member is joined to the flexible bag, the two are preferably stitched together along the top rim of the flexible bag. They may additionally, however, be stitched together around the base or lower part of the bag.

The support member may take the form of a bag or box of an appropriate size and shape to fit either inside or outside the flexible bag. Alternatively, it may take the form of an openended tube which supports only the sides of the flexible bag and not the base.

Preferably, the support member takes the form of an inner lining for the flexible bag, and is slightly larger in circumference than the flexible bag, such that insertion of the support member into the bag pulls the fabric of the latter taut around the former. This tension in the flexible bag means that the container "springs" easily open, immediately ready for filling, when in use. The liner can still be attached to the flexible bag, for instance by stitching at the corners of the container.

The support member may be made from any suitable semi-rigid material, for instance, plywood. However, it is preferably made from a semi-rigid plastics material, more preferably a material comprising two outer layers, the gap between which is divided into a series of partitions by elongate spacer elements whose longitudinal axes run in a direction substantially parallel to the planes of the outer layers (the spacer elements themselves thus being substantially perpendicular to the planes of the outer layers). A suitable material is currently available under the trade mark Correx

Such materials are available having a variety of different spacings for the spacer elements of the inner layer. They are currently used for the manufacture of boxes and other packaging.They are reasonably flexible, and yet can provide sufficient rigidity to the flexible bag to allow it to stand alone and to be easily filled without collapsing.

A further advantage of such materials is that they have a reasonable flexibility and, if crushed or distorted out of shape, can usually be re-formed into their original shape and re-used. Thus, the support member in the container of the present invention is difficult to damage. If accidentally crushed, eg: by a heavy vehicle, it can usually be restored to its correct shape and re-used.

The support member may be made from a water impermeable material, or may be coated with a water impermeable layer, for instance if the container is to be used to store and transport moist or wet products. However, it is not essential that the support member be water impermeable. Even if wet products are to be stored in the container, an additional inner liner, of a water impermeable material, could be used in association with the flexible bag and the support member of the container, so as to prevent the passage of moisture into or out of the container.

Whilst the support member may be located either inside or outside the flexible bag, it is preferably located inside as a liner to the flexible bag. This is because semi-rigid materials such as Correx are often not particularly resistant to puncture. The lifetime of the support member is considerably enhanced if it is protected by an outer flexible bag.

Seams in the support member are preferably welded, rather than stitched, together. This is a particularly convenient way of

connecting together pieces of a material such as Correx~and it overcomes a common disadvantage of existing woven flexible bags, from which finely powdered or wet materials can escape through stitch holes at seams in the woven fabric. A container in accordance with the present invention is particularly advantageous because the presence of the support member also reduces the amount of product escape through stitch holes present in the flexible bag.

Semi-rigid, multi-layer materials such as Correx can often be scored so as to allow them easily to be folded into a desired shape. Thus, a single length of a suitable semi-rigid material may be scored at three lines along its length so as to form three corners of a four-sided tube, and the two free ends welded together to form the fourth corner. This tube can then be used as an inner or outer support member for a flexible bag. Alternatively, the semi-rigid material may simply be bent into an appropriate shape. A material such as Correx, for instance, may be bent over a stiff, straight edge, beyond its elastic limit, to form a hinge-like crease in the material.This is often preferable since when the material is scored, this ruptures one of the outer layers and allows the ingress, into the partitions of the inner layer of the material, of products stored in the container or of moisture or other contaminants from the atmosphere.

The container of the present invention is preferably collapsible, e.g. by folding, into a reasonably flat construction which can easily be stored. A suitable construction of the support member would allow the container easily to be collapsed and re-assembled when ready to be filled with a product. Again, scoring along the semi-rigid material at appropriate positiol1s may be used so as to facilitate disassembly of the container.

The container may have the form of a square- or rectangularsided box. The sides of this box may taper slightly, outwards and upwards from the base of the container, to allow several containers to be stacked together in nesting formation, particularly if the container is open-topped. Such a construction also means that the container falls open, and stays open, at its upper end relatively easily when the container is placed on the ground or another surface. This in turn makes the container easier to fill, particularly advantageous when it is to be used for the storage or transportation of moist products such as mortar.

The lifting handles of the container may be attached in any suitable manner to the sides of the container. They are preferably sewn onto the sides of the flexible bag, which will have more structural strength than the support member.

Typically, the container will comprise four lifting handles, which may be positioned either one at each corner of the container or one in the middle of each of its sides.

Alternatively, the container may only comprise two lifting handles, one on each of two opposite sides of the container.

The lifting handles may be used to lift the container using, for example, the tines of a fork lift truck. However, because the container is rigid enough to stand alone, it may also be lifted (either full or empty) with its base supported from below.

The lifting handles may be reinforced, for instance, with piano wire.

The container may also comprise a reinforcing band extending circumferentially around the tops of the side walls of the flexible bag. This will increase the strength of the bag in those regions where the lifting handles are likely to take the most strain. The reinforcing band is preferably made from a webbing material or other fabric of a similar strength, and will typically be sewn around the sides of the flexible bag.

It may be further reinforced by the incorporation of a stiffening rod (eg: of steel) under the reinforcing band itself.

Where the semi-rigid material from which the support member is made is a material having two outer layers and an inner partitioned layer, the support member is preferably so arranged in the container that the longitudinal axes of the spacer elements defining the partitions run substantially parallel to the base of the container (i.e. roughly horizontal in use). This provides greater rigidity to the container as a whole, since materials of this type tend to be more rigid in one direction and more flexible in the other, perpendicular, direction.

More preferably, the support member is made up of two adjacent layers of a semi-rigid material or materials, further to increase rigidity. Where the semi-rigid material is of the partitioned type, then the two layers will preferably be arranged such that the longitudinal axes of the spacer elements in one run substantially perpendicular to the longitudinal axes of those in the other. This crosslamination increases the rigidity of the double-thickness support member.

The support member preferably includes one or more electrically conductive elements, such as conductive metal strips These could conveniently be incorporated between the two outer layers of a semi-rigid material comprising two outer layers and an inner partitioned layer. The conductive strips reduce the build-up of static electricity in materials stored inside the container. Static build-up can lead to explosions in some very fine powdered materials which might typically be stored in the container, such as starch. A conductive strip to reduce the static is less easily incorporated into a conventional woven flexible bulk container than it is into the support member of a container in accordance with the present invention.

The container, with its associated support member, is preferably of such a strength that it can support up to fourfive times its own weight. It should be possible for four or five such containers, when fully loaded, to be stacked one on top of another for storage.

The container may additionally comprise a removable reinforcing base, which may be placed inside the flexible bag so as to provide extra support and rigidity, particularly in the case where the support member takes the form of a foursided, open-ended tube with no base of its own. The reinforcing base might conveniently comprise an inner layer (around 50-lOOmm thick) of polystyrene, sandwiched between (and preferably glued to) two outer layers of plywood. The base would preferably be supplied as a separate item, to be placed inside the container when the latter is ready for use.

When not in use, a large number of such bases could easily be stacked one on top of the other, for storage.

The present invention provides, in addition to the above described container, a semi-rigid support member for use as part of, or in association with, such a container. This support member may, for instance, take the form of a bag to be used as a lining for the flexible bag or as an outer cover for it.

The present invention will now be described by way of example only and with reference to the accompanying illustrative drawings, of which: - Figure 1 shows a semi-rigid bulk container in accordance with the present invention; - Figure 2 is part of a cross section taken along the line II-II in Figure 1; - Figure 3 shows an alternative semi-rigid bulk container in accordance with the invention; - Figure 4 is a part cross section taken along the line IV IV in Figure 3; - Figure 5 is a schematic cross-section taken through part of the support member of the container shown in Figure 1; - Figure 6 shows a further example of a semi-rigid bulk container in accordance with the invention - Figure 7 shows a removable reinforcing base for use with the container shown in Figure 6; and - Figure 8 shows the container of Figure 6, in its collapsed position.

Detailed Description of the Drawings Referring firstly to Figure 1, there is shown a semi-rigid bulk container 1 in accordance with the present invention.

The container comprises an outer flexible bag 2 made from a relatively high strength woven material such as is used to make conventional flexible bulk containers. It also comprises an inner support member 3 (in the form of a four-sided, openended tube) made from a semi-riaid plastics material, in this

case that sold under the trade mark CorrexS The structure of this material is shown in more detail in Figure 5.

The bag also comprises four lifting handles, 4, one set at each corner of the container. The lifting handles are made from a high strength webbing material and are sewn to the insides of the outer flexible bay 2. Each comprises a Ushaped loop, the free ends of which are fastened to bag 2.

The container takes the form of an approximately square-sided box, although its dimensions A, B and C will vary according to customer requirements, including the type of product with which the container is to be filled. For instance, in some areas of use, the container may be of capacity 300 e or 250 Q or less; in others, its capacity will be much larger than this. The sides of the outer flexible bag 2 are stitched together (stitching shown in places). In contrast, seams in the support member 3 (which constitutes a lining for the container) are welded together.

Because of the presence of the support member 3, the container 1 has sufficient rigidity to retain its box-like shape even when empty. The container, or a number of such containers, can thus easily be filled with whatever product is to be stored and transported in it. For instance, a number of containers can be lined up in a row and filled sequentially in a much less difficult and time-consuming manner than would previously have been necessary.

Figure 2 shows a cross section taken through the container 1 in Figure 1, along the line II-II. The inner support member 3 and the outer woven bag 2 are seen adjacent one another.

In this particular case. semi-riaid support member 3 is made

from Correx+;which is water impervious. Thus, either wet or dry products may be stored in container 1 without the risk of leakage through its sides.

Support member 3 is fabricated from a flat sheet of Correxk which is bent or folded at appropriate points to form the four sides needed to line the outer bag 2. The whole container can easily be folded flat when not in use, for ease of transportation and storage. Despite this, once erected, the container is capable of standing alone even when empty.

The internal structure of the support member 3 is not shown in detail in either of Figures 1 or 2. It can be seen from Figure 2, however, that the support member and the outer flexible bag 2 are joined together at the top rim of the container 1, typically using stitching. They may also be joined together, if desired, by stitching around the bottom edges of the support member.

The semi-rigid bulk container 10 shown in Figure 3 is of very similar construction to that shown in Figure 1, and comprises a flexible outer bag 11 of a woven material and an inner

support member 12 made from CorrexLor a' similar semi-rigid plastics material. The outer bag 11 and support member 12 are preferably joined at the rim of the container, by stitching the two components together.

Container 10 comprises two lifting handles, 13, by which it may be lifted using the tines of a fork lift truck. These handles are stitched to the insides of the flexible bag 11, as shown.

Again, the dimensions A, B, C of container 10 are chosen according to the requirements of a particular customer.

Figure 4 shows part of a cross section taken along the line IV-IV in Figure 3. Support member 12, seen adjacent the outer bag 11, is constructed in the same way as support member 3 of the container shown in Figure 1. Container 10 also folds flat for ease of transportation and storage, when empty.

Figure 5 shows in more detail the internal structure of the material from which the support members 3 and 12 are constructed. Figure 5A is a section taken through a short length of such a material. The material is seen to comprise two outer layers 20, of plastic cardboard. The gap between these layers is divided into a series of partitions 23 by elongate spacer elements 21. The exact spacing of elements 21 may differ between different types of material.

The material shown in Figure 5 is semi-rigid. The outer layers 20 are in this case, although they need not be, impermeable to water.

The longitudinal axes of the spacer elements 21 run in planes perpendicular to the plane of Figure 5A. In the containers 1 and 10 of Figures 1 and 3 respectively, greater rigidity is achieved if the direction of these longitudinal axes in the support members 3 and 12 is roughly parallel to the base of each container.

Figure 5B shows schematically how the semi-rigid material shown in Figure 5A may be bent into an appropriate shape, allowing the material to be used as an inner lining or outer reinforcing layer in association with a flexible bag of a particular shape.

Figure SC shows schematically how sharper angles can be obtained when shaping a support member made from the material shown in Figure SA. Here, one of the outer layers 20 has been scored in a direction parallel to the longitudinal axes of the spacer elements 21. The scoring, at point 22, breaches the outer layer 20 and allows the material to be folded to form a more acute angle, and hence to be shaped into a corner.

However, scoring the material in this way means that products can enter the inner, partitioned layer of the material through the gap 22. This is thus not a particularly favourable way of shaping a support member made from such a material.

Whilst the support members 3 and 12 of containers 1 and 10 respectively are preferably joined to the outer bags 2 and 11 at the rim, the support members may alternatively be supplied as completely separate elements which are then inserted into the outer flexible bags, as liners, when the containers are ready for use.

The container shown in Figure 6 comprises an outer woven

rlexible bag 30 and an inner Correx4supp6rt member 31, in the form of a four-sided open-ended tube. The container has four lifting handles 32, each reinforced with piano wire. The top edges of the outer bag 30 are reinforced by means of rim band 33, of a woven webbing material, underneath which are provided 5mm steel reinforcing rods 34, for added strength.

Shown schematically is the position occupied inside the container, in use, of a removable base 35. This is provided as a separate item, placed inside the container when the latter is ready for use. It increases the strength and rigidity of the overall container.

Typical dimensions for the container, ie: 900 x 900 x 600mm, are indicated in Figure 6. These dimensions are exemplary only.

Removable base 35 is shown in more detail in Figure 7. The base comprises an inner layer 36 of polystyrene (thickness 50mm) sandwiched between, and glued to, two outer layers 37 of relatively thin plywood.

Figure 8 shows schematically how the container shown in Figure 6 may be collapsed when empty, for convenient storage and transportation. Base 35 is removed, and the container is then flattened, the base of the flexible bag 30 easily stretching on bias to the required diagonal length.

Claims (35)

Claims

1. A semi-rigid bulk container comprising a flexible bag made of a woven fabric; and an associated support member made from a semi-rigid material which increases the rigidity of the flexible bag and allows the container to retain when not full substantially the same shape as it would have when full.

2. A container according to Claim 1, adapted for use in the storage or transportation of mortar or mortar-like products.

3. A container according to Claim 1 or Claim 2, wherein the support member is made from a semi-rigid plastics material.

4. A container according to Claim 3, wherein the support member is made from a material comprising two outer layers, the gap between which is divided into a series of partitions by elongate spacer elements whose longitudinal axes run in a direction substantially parallel to the planes of the outer layers.

5. A container according to Claim 4, wherein the support member is so arranged in the container that the longitudinal axes of the spacer elements defining the partitions run substantially parallel to the base of the container.

6. A container according to any one of the preceding claims, having the form of a square or approximately square-sided box.

7. A container according to any one of the preceding claims, wherein the support member has the form of an inner lining for the flexible bag.

8. A container according to Claim 7, wherein the support member is slightly larger in circumference than the flexible bag, such that insertion of the support member into the bag pulls the fabric of the latter taut around the former.

9. A container according to any one of Claims 1-6, wherein the support member is located outside of the flexible bag in use.

10. A container according to any one of the preceding claims, wherein the support member is detachable from the flexible bag.

11. A container according to any one of Claims 1-9, wherein the support member and the flexible bag are stitched together.

12. A container according to any one of the preceding claims, wherein the support member has the form of an open-ended tube.

13. A container according to any one of the preceding claims, wherein the support member is made from a water impermeable material or is coated with a water impermeable layer.

14. A container according to any one of the preceding claims, comprising an additional inner liner for use in association with the flexible bag and the support member of the container.

15. A container according to any one of the preceding claims, wherein any seams in the support member are welded together.

16. A container according to any one of the preceding claims, wherein the support member is made from a single length of a semi-rigid material which is scored and folded at three lines along its length so as to form three corners of a four-sided tube, the two free ends of the material being welded together to form the fourth corner.

17. A container according to any one of Claims 1-15, wherein the support member is made from a single length of a semi-rigid material which is bent into the desired shape.

18. A container according to any one of the preceding claims which is collapsible into a substantially flat configuration.

19. A container according to any one of the preceding claims, having the form of a square- or rectangular sided box, the sides of which taper outwardly and upwardly from the base of the container.

20. A container according to any one of the preceding claims, additionally comprising one or more lifting handles.

21. A container according to Claim 20, wherein the lifting handle(s) are sewn onto the sides of the flexible bag.

22. A container according to Claim 20 or Claim 21, comprising four lifting handles.

23. A container according to Claim 22, wherein the lifting handles are positioned one at each corner of the container.

24. A container according to Claim 20 or Claim 21, comprising two lifting handles, one on each of two opposite sides of the container.

25. A container according to any one of Claims 20-24, wherein the lifting handle(s) are reinforced.

26. A container according to any one of the preceding claims, additionally comprising a reinforcing band extending circumferentially around the tops of the side walls of the flexible bag.

27. A container according to Claim 26, wherein the reinforcing band is made from a webbing material.

28. A container according to Claim 26 or Claim 27, additionally incorporating a stiffening rod under the reinforcing band.

29. A container according to any one of the preceding claims, wherein the support member is made up of two adjacent layers of a semi-rigid material or materials.

30. A container according to Claim 4, wherein the support member is made up of two adjacent layers of the semi rigid material, the two layers being arranged such that the longitudinal axes of the spacer elements in one run substantially perpendicular to the longitudinal axes of those in the other.

31. A container according to any one of the preceding claims, wherein the support member includes one or more electrically conductive elements.

32. A container according to Claim 4 and Claim 31, wherein the electrically conductive element(s) are incorporated between the two outer layers of the semi-rigid material.

33. A container according to any one of the preceding claims, additionally comprising a removable reinforcing base.

34. A semi-rigid bulk container substantially as herein described with reference to the accompanying illustrative drawings.

35. A semi-rigid support member for use as part of a container according to any one of the preceding claims.