GB2136771A - Containers for bulk material - Google Patents

Abstract

A container for bulk materials comprises a bottom wall, two side walls joined to the bottom wall, two end walls (4, 5) joined to the bottom wall and the side walls, and a top closure (8), at least part of the top closure (8) being formed by two overlapping layers of fabric (11, 12) each joined to or integral with the upper part of a respective end wall and being stitched together along at least one stitching line (15, 16) extending parallel to the side walls, an opening (13) into the container being formed below the upper one of the overlapping layers. <IMAGE>

Description

SPECIFICATION Improvements relating to containers for bulk material This invention relates to containers for bulk material, such as powdered or granular material for use in chemical processes or in agriculture.

Our U.K. Patent No. 1581438 is directed to a container having a bottom wall, two side walls each joined to the bottom wall, two end walls each joined to the bottom wall and to the side walls, a top wall joined to the side walls but not to the end walls and an inner top or lid joined to and extending between the upper edges of the end walls and below the top wall, both the top wall and the inner top or lid having openings therein through which the container may be filled.

The container may be filled through a filling tube inserted through the openings in the top wall and the inner lid. During filling, the container may be supported by inserting the tines of a fork-lift truck into the space between the top wall and the inner lid so that the container is supported from the tines, which engage the inner surface of the top wall.

Similariy, the filled container may be transported by suspension of the top wall from the tines of a fork-lift truck. Care must be taken by the fork-lift truck operator when positioning the tines, as there is a danger of the tines fouling the opening in the inner lid, so tearing the fabric of the inner lid, damaging the container and possibly exposing the contents to the atmosphere. In view of the filling openings through the top wall and the inner lid full protection of the contents is in any case lacking, and it is common practice to use an impervious inner liner within the container, that is capable of being fully closed to protect the contents.

Other types of container have lifting structures different from the top wall arrangement described above, one common example being the provision of two or more lifting loops secured to the side walls of the container. The top of such a container may be closed by a fabric lid, having an opening therethrough, which again limits the protection afforded to the contents. Simple box-type bags with no special lifting attachments may suffer a similar defect.

The object of the present invention is to mitigate the aforesaid disadvantages.

According to the invention a container for bulk materials comprises a bottom wall, two side walls each joined to the bottom wall, two end walls each joined to the bottom wall and the side walls, and a lid extending over the side and end walls, at least part of the lid being formed by two overlapping layers of fabric each joined to the upper part of a respective end wall and being stitched together along at least one stitching line extending substantially parallel to the side walls, an opening into the container being formed below the upper one of the overlapping layers.

The two overlapping layers effectively form a valve through which a filling tube may be inserted to fill the containers with material. When the filling tube is withdrawn the opening is protected by the overlying upper layer, so protecting the contents of the container from the atmosphere.

Preferably, the overlapping layers of fabric are stitched together along two lines, one adjacent to each side wall of the container. The stitching may simply secure the layers together or it may alternatively stitch the layers to the upper edges of the side walls themselves. In either case the stitching completes continuous lines of connection between the end walls and helps to prevent these moving apart under the pressure of material within the container.

In one embodiment of the invention a first layer of the inner top extends from a first end wall and terminates in an edge lying closer to the second than to the first end wall, a second layer of the inner top extends from the second end wall over the first layer and terminates in an edge lying closer to the first than to the second end wall, the edges of the two layers are free except at the stitching line or lines and the edges of the first layer forms the opening into the container.

In an alternative embodiment the overlapping layers are formed by a length of fabric extending between the upper parts of the end walls and folded substantially to an S-shape to form an outermost, centre and innermost layer, all three layers being joined by the stitching line or lines. The opening may be formed in the innermost one of the three layers or in either fold line between adjacent layers.

Other fabric arrangements that give the required overlapping relatonship are also possible.

The container may be formed with any suitable lifting arrangement, one example being a plurality of lifting loops secured to the side walls of the container. More preferably, the lifting arrangement comprises a top wall joined to the side walls but not the end walls and extending over the lid. In such a container, preferably the bottom wall, side walls and top wall are formed from a single length of woven fabric stitched at its free ends to form a continuous lifting loop. The end walls and inner top are formed from similar fabric stitched as required to the base and side walls. Conveniently the fabric is woven from a high tenacity synthetic fibre, for example polypropylene, polyethylene terephthalate, rayon, nylon or mixtures thereof. Polypropylene is particularly preferred as it is relatively cheap and can be woven to have the required strength.

The invention will be better understood from the following description of particular embodiments of containers in accordance therewith, given 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 shows in more detail the inner top of the container of Figure 1; and Figure 3 is a perspective view from above of part of a second embodiment of container.

As shown in Figure 1 a container according to the invention has a bottom wall 1, side walls 2 and 3, two end 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 container also includes an inner lid 8. The end walls 4 and 5 are stitched to the side walls 2 and 3 as indicated by the lines of stitching 9 and the end walls are also stitched to the bottom wall 1 as indicated by the lines of stitching 10. The end walls are not stitched to the top wall 6 and neither is there any stitched connection between the inner lid 8 and the side walls 2 and 3.

As will be seen from Figure 2 the inner lid 8 is formed by a first layer of fabric 11 extending from the upper edge of the end wall 5 and a second layer of fabric 12 extending from the upper edge of the end wall 4. The layer 11 terminates in an edge 13 closerto the end wall 4 than to the end wall 5, while the layer 12 terminates in an edge 14 closer to the end wall 5, and thus overlaps the layer 11 in the central part of the lid. The overlapping edges of the two layers 11 and 12 are joined together by stitching 15, 16 respectively extending substantially parallel to the side walls and completing a continuous connection between the upper edges of the end walls to tie these together across the top of the bag.

In use, a filling tube 17 may be inserted between the layers 11 and 12so that the end of the tube lies clear of the edge 13. Thus, material supplied through the tube will fall into the container in order to fill this.

With the tube withdrawn it will be seen that the overlapping arrangement gives excellent protection to the contents of the container. If desired an impervious inner liner may be included in the inner container, the liner having a neck that, for filling purposes, can be brought between the two layers so that the filling tube may be inserted into it.

It will be seen that when the container is lifted on the top wall by the tines of a fork-lift truck inserted as shown in Figure 1,the tines will slide over the top surface of the upper layer 12 of the lid 8 and will be unable to foul the filling opening defined by the edge 13 of the lower layer. Alternatively, the filled contain ermay, if desired, be handled buy a crane, and in this case the fabric of the top wall may be gathered together towards the centre of the wall and secured in position by a tie to form a single lifting point engageable by a crane hook.

Figure 3 shows an alternative form of container. In this embodiment the end walls 4', 5' and the lid are formed from a single length of fabric, folded in the central region of the lid to an S-shape to form an outermost layer 20, central layer 21 and innermost layer 22. The three layers are stitched together at the sides of the lid by lines of stitching 23, 24 extending parallel to the side walls. The opening into the container may be formed in one example by a cut along line a on the fold between the middle and innermost layers 21 and 22. The cut may extend from one line of stitching to the other, orfor a more limited distance as indicated in Figure 3.As an alternative to a cut along the fold line the innermost layer 22 may be cut with a slit or with a hole of any convenient shape as long as the cut is of such a size that the opening defined thereby is entirely covered by the overlying layers.

In a further embodimentthe opening is formed by a cut along line b on the fold between the outermost and middle layers 20 and 21, the cut extending either the full distance between the lines of stitching or for part only of this distance. Such a cut will lie at least partially below the plane of the outermost layer and will not be fouled by fork-lift truck tines presented in the direction of the arrow. The folded construction will give good protection to the container contents, and if required the container may be completely closed by closing the cut by staples, tape or any other suitable means. It may then be possible to dispense entirely with an inner liner for the container.

The container shown in Figure 3 is provided with lifting loops 25 secured along the vertical seams between adjacent side and end walls of the container. It may, of course, be modified by substituting any other convenient arrangement of lifting loops. In a further alternative, the lid structure shown in Figure 3 may be substituted for the lid structure shown in Figures 1 and 2, to give a container having a top wall that may be filled and handled in exactly the same way as the embodiment shown in Figures 1 and 2.

In the containers thus far described the edges of the inner top are not secured in any way to the side walls 2,3 of the container. In a modified embodiment, however, those edges may be stitched to the side walls either along the full length thereof orfor any required part of the length, for example for a distance co-terminous with the stitching lines securing the layers together.

When a container as described having a top wall such as 6 is lifted, the load is taken by the continuous lifting loop comprising the bottom wall, side walls and top wall. If desired, this may be strengthened by stitching to the edges of the lifting loop lengths of additional fabric, for example, of webbing such as is commonly used for vehicle seat belts. The containers described will generally include a seam in the lifting loop positioned on the bottom wall of the container. However, it is not necessary that the seam be so positioned, and 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 will be more than one seam such as 7.

In all instances in this specification and claims where one element is referred to as being "joined to" another element it will be understood that the elements may be integral sections of a single length of fabric, or they may be separate lengths of fabric stitched or otherwise secured together.

The top wall may be continuous as shown in Figure 1, or it may be formed with a slot or other filling opening if it is desired to gain access to the openings in the inner top through the top wall.

The bottom wall of the container may be fitted with an outlet spout through which the container may be discharged, the spout being openable or closable will, so rendering the bag re-usable. A discharge structure other than a spout may alternatively be used. In a further arrangement no specific discharge means is provided, and the contents may then be discharged from the container merely by cutting an opening in the bottom wall and liner if provided, and allowing the contents to flow out. The container is then discarded.

Claims (8)

1. Acontainerfor bulk materials, the container comprising a bottom wall, two side walls each joined to the bottom wall, two end walls each joined to the bottom wall and the side walls, and a lid extending over the side and end walls, at least part of the lid being formed by two overlapping layers of fabric each joined to the upper part of a respective end wall and being stitched together along at least one stitching line extending substantially parallel to the side walls, an opening into the container being formed below the upper one of the overlapping layers.

2. A container according to claim 1 in which the overlapping layers of fabric are stitched together along two lines, one adjacent to each side wall of the container.

3. A container according to claim 2 in which the stitching only secures the layers together.

4. A container according to claim 2 in which the stitching stitches the layers together and to the upper edges of the side walls,

5. A container according to any one of the preceding claims in which a first layer of the inner top extends from a first end wall and terminated in an edge lying closer to the second than to the first end wall, a second layer of the inner top extends from the second end wall over the first layer and terminates in an edge lying closer to the First than to the second end wall,the edges of the two layers are free except at the stitching line or lines and the edge of the first layer forms the opening into the container.

6. A container according to any one of claims 1 to 4 in which the overlapping layers are formed by a length of fabric extending between the upper parts of the end walls and folded substantially to an S-shape to form an outermost, centre and innermost layer, all three layers being joined by the stitching line or lines.

7. A container according to any one of the preceding claims in which the lifting arrangement comprises a top wall joined to the side walls but not the end walls and extending over the lid.

8. A container for bulk materials, substantially as herein described with reference to Figures 1 and 2 or to Figure 3 of the accompanying drawings.