GB2168949A

GB2168949A - Flexible bulk container

Info

Publication number: GB2168949A
Application number: GB08432759A
Authority: GB
Inventors: Denis Pollitt
Original assignee: LOLIFT B G Ltd
Current assignee: LOLIFT B G Ltd
Priority date: 1984-12-29
Filing date: 1984-12-29
Publication date: 1986-07-02
Also published as: GB8432759D0; GB2168949B

Abstract

A flexible bulk container has a base (1), four side walls (2 to 5) and a top wall (6) joining the upper edges of two opposite side walls (2, 3). Each of the other side walls (4, 5) has an upwardly projecting extension (12) having an opening (17) and so forming an additional lifting section lying immediately below the top wall. When the container is lifted, load is then transferred directly into all four side walls. <IMAGE>

Description

SPECIFICATION Intermediate bulk containers This invention relates to intermediate bulk containers. Such containers are generally manufactured from woven fabric and used for the conveyance and storage of bulk material, such as powdered or granular material for use in chemical processes or in agriculture.

There have been many different proposals for intermediate bulk containers, both for the container structure as such and for the means by way of which the container may be lifted. The general requirements are to provide lifting means which may readily be engaged by the tines of a fork lift truck or by a lifting hook and that will ensure good load transference from the lifting means into the side wall fabric of the container. There is also a requirement that the container retain a compact shape, usually substantially square in horizontal cross-section, when it is filled and lifted. The invention seeks to provide a container having these desirable qualities.

According to the invention a flexible intermediate bulk container comprises a base, four side walls extending upwardly from the base, and a top wall joining the upper edges of two opposite side walls and forming a lifting band, in which each of the other two opposite side walls has an upwardly projecting extension forming a lifting section lying immediately below the top wall.

Containers comprising a base, four side walls and a top wall joining the upper edges of two op posite side walls are known from our earlier patent specifications No. 1581437 and 1581438. In these constructions the top wall forms a lifting band for the container, the whole of the lifting stress being taken by that'band and transmitted into the side walls joined by that band. In the present invention the container is modified by extending the two other opposite side walls upwardly so that each terminates in an additional lifting section lying im mediately below the top wall that forms the main Wing band. Thus, to lift the container both the main lifting band and the additional lifting sections are engaged so that the lifting load is transmitted directly into all four side walls, so significantly im proving the stress distributions in the container.In deed, this may lead to a lighter weight fabric being used than may otherwise be the case, or the omis sion of additional side wall reinforcement that may otherwise be necessary. A further advantage of transmitting lifting load directly into the other two opposite side walls is that this inhibits any tend ency of those side walls to bulge outwardly and thus assists the maintenance of the container in a generally square horizontal cross-section, with re sultant space advantages when stacking the filled containers Preferably each extension comprises a bight and two legs, each leg being joined to an upper edge of the respective side wall from which it extends.

Particularly preferred embodiments of containers are those in which the combined width of the legs of each extension substantially equals the width of the side wall from which that extension extends, and wherein the free end of one leg is joined to one half of the upper edge of the respective side wall, and the free end of the other leg is joined to the other half of the upper edge of the respective side wall. The joint may be a direct joint, i.e. the covering of the extension may be integral with the fabric of the side wall or may be stitched directly to the fabric of the side wall, or it may be an indirect joint utilising an intermediate section of fabric between the upper edge of the side wall and the extension.

It is particularly preferred if the length of each extension, measured along the centre line thereof from the junction of one leg with the upper edge of the side wall to the junction of the other leg with the upper edge of the side wall, is substantially equal to the length of the top wall measured along the centre line thereof between the upper edges of the two side walls which the top wall joins. This has been found to be the optimum relationship for substantially uniform stress transfer into the side walls of the container.

The basic structure of base, side walls and top wall may be formed in any one of a number of ways, but preferably the base, the top wall and the two opposite side walls which are joined by the top wall are formed from one or more pieces of fabric stitched to form a continuous lifting loop.

One single continuous length of fabric is particularly preferred, the two free ends of the fabric being joined by a seam positioned in or adjacent to the base of the container. The fabric used in the manufacture of the container may be any suitable fabric, and commonly the fabric will be woven from a high tenacity synthetic fibre, for example polypropylene, polyethylene terephthalate, rayon, nylon or mixtures thereof, using any suitable weave pattern. A particularly preferred material for the container is 14 x 11 per square inch plain woven polypropylene of 2000 denier; loads of 1500 Kg and even more may safely be handled in containers made from such fabric.

The container will generally be provided with an impervious inner liner within the space enclosed by the container side walls in order that the material to be carried is fully protected, and such liner will usually be formed with a filling neck. When the container is to be emptied a cut can be made in the bottom wall of both the container and the inner liner (if provided), so that the contents merely fall from the container, which can then be disposed of.

If the container is required to be re-usable a discharge spout arrangement may be fitted to the bottom wall of the container, for example as described in patent specification No. 1431582 or 1536237.

Particular embodiments of containers are described in the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view from above of a first embodiment of container in accordance with the invention; Figure 2 is a perspective view from below of the container of Figure 1; Figure 3 is a view of the container with part cut away showing it in a filling position; Figure 4 is a view of the container of Figure 1 in a lifting position; and Figure 5 is a view corresponding to Figure 2 of a second embodiment of container in accordance with the invention.

As shown in Figure 1 a container according to the invention has a base or bottom wall 1, a first pair of opposite side walls 2 and 3, a second pair of opposite side walls 4 and 5 and a top wall 6.

The bottom wall 1, side walls 2 and 3 and top wall 6 are formed from a single length of woven fabric, the ends of which are sewn together along a seam 7 at the base of the bag as shown in Figure 2. This length of fabric thus forms a continuous lifting loop. The two other side walls 4 and 5 are each stitched to the side walls 2 and 3 as indicated by the lines of stitching 9 and are also stitched to the bottom wall 1 as indicated by the lines of stitching 10. The top wall 6 is formed with a central filling opening 11, which is shown as a circular opening but may be of any suitable shape or may simply be a slit cut in the fabric parallel to the direction of the side walls 4 and 5.

Each of the side walls 4 and 5 is formed with an upwardly projecting extension 12 forming a lifting section 9 immediately below the top wall. Each lifting extension is of woven fabric integral with the woven fabric of the respective side wall and of equal width to the side wall. The upper part of the extension is vertically cut along the centre thereof to form two legs 13 and 14, the free upper edges of which are brought together and stitched along a line 15 to form a bight. It will be understood that this operation produces an opening 17 in the upper part of the extension.It will further be seen that the length of each extension, measured along the center line thereof from the junction of one leg with the upper edge (line A-A) of the side wall to the junction of the other leg with the upper edge of the side wall, is substantially equal to the length of the top wall measured along the centre line thereof between the upper edge (line B-B) of the side wall 2 and the corresponding upper edge of the side wall 3.

In use the container will generally be provided with an impervious inner liner, preferably made from a plastics material, and having a filling neck 18. This may be secured around the lower end of a filling spout 19 by a tie member such as 20 and material may then be fed through the spout into the inner liner, the container being suitably supported during this operation. Such support may conveniently be by way of the tines of a fork lift truck introduced below the top wall 6.

After filling, and for further handling, the fabric of the top wall 6 may be gathered together as shown in Figure 4, the extensions of the side walls 4 and 5 also being gathered into the central region of the container. The extensions and the top wall may then be held together in their gathered position by a tie 21 so forming a single lifting point which may be engaged by a crane hook. It will be appreciated that when the container is lifted in this way load will be applied to the top lifting band and to the additional lifting sections formed by the side wall projections, and load will thus be transmitted into the fabric of all four side walls.This enables a strong, safe container to be made from a lighter fabric than may otherwise be the case, and the load transference into all four side walls assists in maintaining the container in a substantially square horizontal cross-sectional configuration, resisting the spreading effect due to the pressure of the bulk material in the container.

Figure 5 shows a somewhat modified container, wherein the extension of each of the side walls 4 and 5 is formed by a length of fabric separate from the side wall fabric. This length of fabric is folded to form a bight 22 and two spaced legs 23, 24, each having a width substantially equal to half the width of the upper edge of the respective side wall.

The free end 25 of one leg is stitched at 26 to the upper edge of the side wall, while the free end 27 of the other leg is stitched at 28 to the remaining part of the upper edge of the respective side wall.

The lifting and load transference effects are similar to those already described.

Both the containers described have been shown with the seam 7 in the bottom wall of the container, but it is not necessary that this seam be so positioned, as it may lie in either of the side walls 2 or 3, or even in the top wall 6. The continuous lifting loop formed by these walls may be formed from more than one length of material, in which case clearly there would be more than one seam such as 7.

As described, the containers are filled through the centre opening in the top wall. However, in a modified embodiment such opening may be omitted so that the top wall is continuous and its strength unimpaired. Filling may then be effected through either of the openings 17 in the flaps 12 after the container has been gathered in at the top as shown in Figure 4.

The bottom wall of the container may be fitted with an outlet spout through which the contents may be discharged, the spout being openable or closable at will; so rendering the bag re-usable.

Many different outlet arrangements are now used and any of these may be utilised in the container of the invention. However, it is not necessary to provide an outlet spout, and the contents may then be discharged from the container merely by cutting an opening in the bottom wall and liner and allowing the contents to flow out. The container is then discarded.

Claims

1. A flexible bulk container comprising a base, four side walls extending upwardly from the base, and a top wall joining the upper edges of two opposite side walls and forming a lifting band, in which each of the other two opposite side walls has an upwardly projecting extension forming a lifting section lying immediately below the top wall.

2. A flexible bulk container according to claim 1 in which each extension comprises a bight and two legs, each leg being joined to an upper edge of the respective side wall from which it extends.

3. A flexible bulk container according to claim 2 in which the combined width of the legs of each extension substantially equals the width of the side wall from which that extension extends, the free end of one leg is joined to one half of the upper edge of the respective side wall, and the free end of the other leg is joined to the other half of the upper edge of the respective side wall.

4. A flexible bulk container according to claim 3 formed from woven fabric, in which the fabric of each leg of each extension is integral with the fabric of the respective side wall to which such leg is joined.

5. A flexible bulk container according to claim 3 formed from woven fabric, in which the fabric of each leg of each extension is directly stitched to the upper edge fabric of the respective side wall to which such leg is joined.

6. A flexible bulk container according to claim 3 formed from woven fabric, in which the fabric of each leg of each extension is joined to the fabric of the respective side wall by an intermediate section of fabric between such leg and the upper edge of the respective side walls.

7. A flexible bulk container according to claim 4 or claim 5 in which the length of each extension, measured along the centre line thereof from the junction of one leg with the upper edge of the side wall to the junction of the other leg with the upper edge of the side wall, is substantially equal to the length of the top wall measured along the centre line thereof between the upper edges of the two side walls which the top wall joins.

8. A flexible bulk container according to any one of the preceding claims in which the base, the top wall and the two opposite side walls which are joined by the top wall are formed from one or more pieces of fabric stitched to form a continuous lifting loop.

9. A flexible bulk container substantially as herein described with reference to Figures 1 to 4 or to Figure 5 of the accompanying drawings.