GB2205302A - Container - Google Patents

Abstract

A bulk container for particulate material is formed from a single length of flexible tubular material that defines two side-by-side containment sections, (2, 3) joined by a lifting band (8). Each containment section has a side wall structure (5, 7) closed at its lower end by a base (4, 6). The containment sections are secured together against significant relative movement. <IMAGE>

Description

CONTAINER This invention relates to containers. It has particular relevance to flexible bulk containers such as are used in the storage and transport of materials in granular, powder and other particulate forms, but is also applicable to containers destined for other end uses.

Flexible bulk containers as aforesaid are generally in the form of large bags or sacks, which are often required to carry loads in the range of 0.5 to 2 tonnes, in each case with considerable safety margin above the rated load.

The containers are commonly made from woven fabric, particularly woven polypropylene or other suitable synthetic material.

There have in the past been many proposals for the manufacture of such containers, and the common features of all these containers have been a wall structure closed at a lower end by a base, with lifting means being provided at the upper end of the wall structure. The lifting means is capable of engagement by a fork-lift truck, crane or other lifting mechanism in order to lift the container. Many different wall structures and base constructions are known, and similarly many different forms of lifting means have been suggested. The constant objective has been to simplify contruction of these containers while improving their load capacity and safety, particularly in the interface between the wall structure and the lifting means.

The present invention seeks to provide a container that comes closer to attaining these objectives, and takes a radically different approach to the construction of flexible bulk containers.

According to the invention a container comprises first and second side by side containment sections, each containment section having a base and a wall structure extending upwardly from the base, and a lifting band joining together upper regions of the two wall structures, the lifting band and both wall structures being formed from a single tube of flexible material.

The total load of the container is split between the first and second containment sections. The container is lifted by engaging the lifting band with a forklift truck, crane or other lifting mechanism and it will be appreciated that the lifting load is applied to the full width of the tube of flexible material, the load thus being tranmitted into the full circumferential extent of the material forming the wall structure of both of the containment sections.

Although the tube from which the container is formed may be formed from a plurality of sections that are stitched or otherwise secured together transversely of the tube, maximum advantage is gained from the invention if the tube is a continuous single length of tubular material. In the context of flexible bulk containers the material will preferably be a woven fabric, particularly a tubular woven fabric so that the tube is free from any seams whatsoever.

However, it is also envisaged that the tubular material may be formed from one or more lengths of flat woven fabric joined by a seam or seams extending longitudinally of the tube. In either arrangement the construction is desirably such that the warp threads of the woven fabric extend up the wall structures of the two containment sections and through the lifting band, with weft threads extending around the circumference of the wall structures.

The material of the tube may conveniently be folded and secured to form the base of each containment section, so that the container can then be formed from a single piece of material. There is obviously considerable manufacturing advantage to be gained from this, as well as safety and operating advantages since the lifting integrity of the container is not weakened by any joined areas.

The container, at least immediately prior to filling, must have means through which each containment section may be filled. In its simplest and most preferred form, this is a slit cut in the flexible material at an upper part of each containment section, the slit extending substantially parallel to the direction of load transmission through the lifting band and the wall-structure so that it does not materially weaken the lifting capacity of the material. In the preferred woven construction each slit is thus parallel to the warp threads. Each containment section may thus be independently filled through its own individual filling slit. Alternatively, a single filling slit could be provided in the flexible material where it forms part of the lifting band, such slit again extending parallel to the direction of the lifting forces.In this embodiment a tube may be inserted through the slit and directed into either one of the containment sections so that both sections may be filled in turn by way of the single slit. In a further alternative, filling may be effected through the bases of the containment sections, each base being formed with a filling opening that can subsequently be closed for transportation of the container after it has been filled.

Preferably means are provided for joining the containment sections together below the upper regions of the wall structures thereof, in order to hold the containment sections in adjacent relationship.

This improves the integrity and handling of the container as it prevents the two containment sections from moving away from each other. In one simple form the joining means may be a simple girth band passed around both containment sections. In other constructions, joining may be by way of a suitable shear resistant adhesive applied between adjacent side walls of the two containment sections, or by providing means securing together the bases of the two containment sections so that they are joined substantially parallel to the direction of the lifting loop. One particularly convenient way in which this may be done is to fold the flexible material so that it forms the required base together with an additional flap.That additional flap may be folded beneath the base to extend towards the other containment section, the additional flaps of the two containment sections then being stitched or otherwise secured together at their free ends. Either'the adhesive arrangement or the joined bases have the additional advantage that when one of the containment sections is emptied the material of that section is retained as part of a continuous loop with the remaining filled section, so that the filled section will still be held suspended from a lifting means engaged with the lifting loop, and will not fall therefrom. There is thus a very easy facility for using half only of the contents of a container, the other half remaining fully protected in its own containment section until required for use.

The lifting band may be in the form of the simple flattened tube, which will then have a width substantially equal to a width dimension of each of the containment sections. To facilitate handling and improve appearance, however, the tubular section forming the lifting band may be gathered together into a handle-like structure, being held in its gathered condition by appropriate ties or by a sleeve of wear-resistant material wrapped around the gathered handle.

Each of the containment sections may, if required, be provided with an impervious inner liner in which the load is actually contained, so protecting the load from ingress of moisture through the material of the containment sections. Whether or not an inner liner is used, protection can also be given by a sheath of impervious material applied around the lifting band and extending downwardly over each of the containment sections for any required distance, if required right to the bottom of the containment sections. The sheath can be lifted for filling purposes, and when rolled down after filling will avoid the necessity of providing a separate closure for any filling opening in the upper part of the container. The sheath may simply be gathered together with the lifting loop in any handle construction that is formed from the loop.

In order that the invention may be better understood, specific embodiments of containers in accordance therewith will now be described in more detail, by way of example only, in conjunction with the accompanying drawings in which: Fig. 1 is a front elevation of a first embodiment of container; Fig. 2 is a side elevation of the container of Fig. 1; Fig. 3 is a plan view of the container of Fig. 1; Figs. 4 and 5 are plan views of alternative embodiments of container; Fig. 6 is a front elevation of yet another embodiment; Fig. 7 is a part bottom plan view of the container of Fig. 6; and Fig. 8 shows the container of Fig. 6 in a different position of use.

Referring to Figs. 1 to 3 there is shown a container 1, comprising first and second side by side containment sections 2 and 3. The containment section 2 comprises a base 4 and a wall structure 5 extending upwardly from the base. The containment section 3 comprises a base 6 and a wall section 7 extending upwardly from the base. The upper regions of the two wall structures 5 and 7 are joined together by a lifting band 8, which is gathered together into the form of a handle 9 and held in its gathered position by a sleeve 10 loosely fitted over the central part of the lifting band.

The lifting band and both wall structures are formed from a single tube of flexible material, and the bases 4 and 6, although they could be stitched into the ends of the tubular material, are preferably formed by suitable folding and securing of parts of the tubular material.

The flexible material is desirably woven polypropylene or other suitable synthetic material, and is preferably tubular woven polypropylene interwoven in any appropriate weaving pattern, usually smooth woven, although twill, basket and rib weaves may alternatively be used.

Whatever the weave, it is preferred that for maximum strength the warp yarns of the fabric extend upwardly in both wall structures and through the lifting band as indicated by the typical warp thread indicated at 11 in Fig. 1. The weft threads will then extend around the wall structures, as indicated by typical wefts 12 and 13 in Fig.

I, and correspondingly weft threads will extend around the lifting band 9. If desired, reinforcing bands comprising warp threads of higher tensile strength may be integrally woven into a base fabric utilising lower strength warp threads, but generally it will suffice for all warp threads to be of the same nominal strength.

When tubular woven fabric is used, it is desirably folded longitudinally into a gussetted formation in order to assist folding during formation of the bases and to assist the tube to fall into the required configuration when the containment sections are filled.

Each containment section has a filling slit 14, 15 respectively, formed in the region of the outwardly facing shoulder in the transition region between the wall structure and the lifting band. The slits extend parallel to the warp thread of the fabric, so that the load-carrying capacity is not impaired. A filling spout may simply be inserted in turn through each of the slits in order to fill the containment sections. After filling, each slit may be closed by stitching or by an adhesive patch if required.

An alternative way in which the containment sections may be filled is by leaving the base open until after filling, or by incorporating a closable filling opening into the base of each section. A filling opening, whether provided in the upper shoulder region or in the base may incorporate a tube actually glued into the containment section and forming a permanent part thereof, the tube being simply attachable to a filling spout in order to fill the respective section. Any such tube may be flexible in order that it can be tied off after filling.

The adjacent side walls 16, 17 of the two containment sections are secured together in adjacent relationship by areas of adhesive 18. The preferred adhesive is a contact adhesive that is strong in shear strength, although a high peel strength is unnecessary as forces tending directly to separate the two containment sections will rarely be experienced.

It will readily be appreciated that the filled container may be lifted by engagement of the lifting loop 9 onto the tine of a fork-lift truck, or onto a hook or similar device of a crane or other lifting means. If the two container sections are filled with a similar weight of material the balance of the load on the tine or hook will be ideal, and if there are any small imbalances then the adhesive 18 will assist in resisting the effects of these.

It will be seen that the lifting forces are transmitted directly from the lifting band into the whole of the wall area of each containment section and, if the bases are integrally formed from the same material, downwardly through each wall section and into the base thereof. The container is thus extremely strong and is free from any stitched connections and transverse joints that will tend to weaken it in any direction tranversely of the applied lifting load.

Figs. 4 and 5 illustrate alternative top formations for the container. In Fig. 4, two modifications are illustrated, usable separately or together. Firstly, the sleeve 10 is replaced by simple ties 21 which may be used to hold together the gathered tubular fabric forming the lifting loop. Clearly, any required number of ties may be applied. Secondly, the adhesive 18 holding the containment sections together is omitted, and the holding is effected by gathering together parts of the material where the sections abut one another, and stitching the gathered parts together as indicated as 22, 23. Each line of stitching may extend from the base of the assembly to the region where the two sections diverge, or for any lesser part of such length.

In the embodiment of Fig. 5 the tubular material forming the lifting loop has not been gathered together, but forms a substantially flat band 26 which may be engaged in flat form by the tine of a fork-lift truck or may simply be gathered together and placed on a crane hook. Fig. 5 also shows a modification wherein each containment section does not have its own separate filling slit, but rather a common filling slit 31 is provided in the upper part of the central region of the lifting band. By inserting a flexible filling spout into the slit 31 and directing it into each container section in turn both sections may be filled. After filling, the slit 31 may be closed by stitching or by an adhesive patch.

Figs 6 to 8 illustrate a further embodiment of container that is generally similar to that shown in Fig.

1, and is similarly manufactured from gussetted tubular woven polypropylene, with the warp threads extending upwardly in the wall structures of the two containment sections 38, 39 and through the lifting loop 40. However, two containment sections are neither adhered nor stitched together at their interface, but are held in adjacent relationship by a modified base structure.

As will be apparent from Fig. 7 each base is formed by a simple folding of the gussetted fabric, the base being closed by a line of stitching 41, 41a. The fabric of the base of a first containment section is extended in its gussetted form to form an additional flap 42 extending towards the other containment section, and similarly the other containment section has an additional flap 43 formed by the gussetted fabric. The two additional flaps are overlapped and joined by stitching at 44 in order that the containment sections are held adjacent, both when the container is standing on the ground, and when it is suspended from a hook as shown in Fig. 6. If it is desired to discharge the contents of one of the containment sections then that section is simply cut open at any suitable lower part thereof and the contents are allowed to discharge.It will be noted that the joining together of the two bases means that a continuous loop of the woven fabric still remains, even though one of the containment sections may have been emptied, and thus that the remaining filled containment section will not fall from the hook.

Obviously, it will drop somewhat in position, but the remaining continuous lifting band will continue to support it on the hook as shown in Fig. 8. It should be mentioned that a similar effect will occur in the Fig. 1 embodiment due to the presence of the adhesive 18, but the simple, wholly-stitched construction of Fig. 6 may be preferred.

For some loads, the protection afforded by the flexible tubular material may be sufficient. Other loads may require more protection against the ingress of moisture, and this can be given in either or both of two ways.

The first way is to incorporate in each containment section an inner liner of impervious material as indicated at broken lines 51 and 52 in Fig. 1. The impervious liner in each containment section extends up to the filling slit, and each liner has an open mouth into which a filling tube passing through the slit may be inserted. After filling the open mouth of the liner may be closed off and secured by a tie such as 53, 54. Note, however, that although this protects the contents, it does not prevent the ingress of moisture into the region between the tubular wall fabric and the inner liner. To give protection against this, a weatherproof tubular jacket may simply be slipped over the containment sections and the lifting loop before the containment sections are secured together either by adhesive as shown in Fig. 1 or by a joining. of the base structures as shown in Fig. 6.The jacket, indicated in dotted outline 61 in Fig. 6, can be gathered together into any sleeve or tie forming part of the handle so that it is held in the required position, and may extend downwardly over as much as is required of the height of each containment section. In order to effect filling, the jacket, which is loose at each lower end, may simply be lifted to expose the filling opening and then pulled down again over the respective containment section once filling has been effected. The jacket will thus give full protection against precipitation and will readily shed water from the container sides without allowing penetration through the tubular fabric, either through fabric interstices, or through the filling slits, which may be left open when such jacket is provided.

It will be appreciated that the container may be made in a range of different sizes, and that it may be made from materials other than woven polypropylene, or indeed any woven fabric. Thus, for smaller or lighter loads, containers made from a multi-ply paper construction can readily be envisaged.

The cross-section of each containment section is principally dictated by the construction of the base thereof, and although the containment sections shown in the drawings are of substantially square cross-section it will be appreciated that this is not essential and that any cross-section may be used.

Claims (15)

1. A container comprising first and second side by side containment sections, each containment section having a base and a wall structure extending upwardly from the base, and a lifting band joining together upper regions of the two wall structures, the lifting band and both wall structures being formed from a single tube of flexible material.

2. A container according to claim 1 in which the tube is a continuous single length of tubular material.

3. A container according to claim 1 or claim 2 in which the tube is formed from woven fabric, warp threads of the woven fabric extend up the wall structures of the containment sections, and weft threads of the woven fabric extend around the circumference of each wall structure.

4. A container according to any one of the preceding claims in which the tube is formed from tubular woven fabric.

5. A container according to any one of the preceding claims in which the material of the tube is folded and secured to form the base of each containment section.

6. A container according to any one of the preceding claims in which each containment section has a filling slit cut at an upper part thereof, the slit extending substantially parallel to the direction of load transmission through the lifting band and wall structure.

7. A container according to any one of the preceding claims and including joining means for joining the containment sections together below the upper regions of the wall structures thereof.

8. A container according to claim 7 in which the joining means is a shear-resistant adhesive applied between adjacent side walls of the two containment sections.

9. A container according to claim 7 in which the joining means is stitching between adjacent parts of the side walls of the two containment sections.

10. A container according to claim 7 in which the joining means comprises means joining together the bases of the two containment sections in a direction substantially parallel to the direction of the lifting loop.

11. A container according to claim 10 in which each base includes an additional flap folded beneath the remainder of the base and extending towards the other containment section, the additional flaps being secured together at their free ends.

12. A container according to any one of the preceding claims in which the lifting band is formed by gathering together part of the material of the tube into a handlelike structure, retaining means being applied around the gathered material.

13. A container according to any one of the preceding claims in which each containment section is provided with an impervious inner liner.

14. A container according to any one of the preceding claims in which a sheath of impervious material extends around the lifting band and downwardly over each of the containment sections.

15. A container substantially as herein described with reference to figures 1 to 3, or figure 4, or figure 5, or figures 6 to 8 of the accompanying drawings.