GB2257417A - Lift bag for bulk material - Google Patents

Abstract

A lift bag for bulk material is made of woven material closed at one end to form the bottom (12) of the bag and is provided with a lifting loop (13) at its upper end. Below the loop (13), V-shaped openings (14) are formed in opposed wall portions of the bag to permit filling thereof and also subsequent engagement of a fork lift or hook with the loop (13) to lift the bag and its contents. Contraction means such as an elasticated portion, pleating or a drawstring, is provided in the upper end portion (16) of the bag which is automatically operative, or which can be operated, in order to contract the outer periphery of the upper end portion (16) of the bag in order to form an at least partial closure of the upper end portion (16) of the bag, and to tauten the bag material adjacent to the contraction means, when the bag is left freestanding with its contents therein. <IMAGE>

Description

LIFT BAG FOR BULK MATERIAL This invention relates to a lift bag for bulk material and having a loop or loops at its upper end by means of which the bag and bulk material contents can be lifted and transported by a fork lift or hook, and which loop(s) comprise direct extensions of the side walls of the bag and forms openings for filling and lifting purposes.

The invention has been developed primarily in connection with a lift bag of the type used by farmers for storage of large volumes of fertilisers, typically up to half tonne in weight, and which comprise an outer liner of woven material, and usually having an inner liner of plastics film (polyethylene or other suitable impervious material) in which the bulk material is stored. The filling of the inner liner usually takes place by first inflating the liner with air to facilitate the pouring in of the material, followed by charging of the inflated liner with the bulk material. The liner is then usually sealed-up by any suitable means, and is either attached to the outer liner or bag by a tie, or is tucked into the outer bag in any convenient way.

The outer liner of the bag has an upper carrying loop by means of which the bag and its contents can be lifted by a fork lift or a hook, and then transported to a storage site.

It is usual for the outer liner of the bag to be a fabric woven from suitably strong and weather resistant material, such as polypropylene, and by reason of the warps and wefts from which the fabric is made, the bag can have sufficient tensile strength in two perpendicular directions, which makes the bag suitably strong to withstand loads which are applied to the wall of the bag during lifting, and during storage.

One known way of making the outer liner involves starting with a supply of woven tube, which is laid flat, and which is secured by stitching along one end to form the bottom of the liner,- and the opposite end is slit midway of the upper overlapping edges, followed by stitching together of these edges which will form the top of the bag.

The upper end of the tube is gathered into a form in which the slits open out to form opposed V-shaped openings in each side of the top end of the tube, and which is bridgedover by a top loop, and then a strip of material e.g. a strip of coated polypropylene is taken around this top loop to strengthen and improve the wear resistance of the loop to render it capable of being engaged by a fork lift arm or hook.

However, while these (and other) ways of forming the loop at the upper end of the bag render the bag suitable for initial filling, handling and storage purposes, they have been found to deteriorate with time when stored out in the open. by reason of continual wind action.

Thus, in that the upper end of the bag (when filled) must be capable of allowing easy entry of a fork lift arm or a hook through the opposed V-shaped openings in order to engage the loop. and also by reason of the inevitable flexing of the upper end of the bag when the bag and heavy contents are lifted via the loop, once the bag is set down again to a free standing mode there will be a tendency for the material of the bag at the upper end, and particularly adjacent to the loop, to become somewhat slack.

Therefore, under fluctuating wind loads, repeated flapping of the woven material causes fretting of the fibres of the warps and wefts, which causes the material to lose substance over a period of time and a consequent loss of strength. Similar damage can also occur to the inner liner.

This is disadvantageous for at least two reasons.

First of all, the weather resisting properties of the bag may suffer, with consequent risk of water coming into contact with the bulk material, which is clearly undesirable, and especially in the case of storage of water soluble fertilisers. Secondly, the loss of strength may cause the bag to tear when lifted again, which is not only undesirable, but also potentially dangerous.

The invention therefore addresses this problem, and seeks to provide a novel structure for the upper lifting end of the bag which is better able to withstand wind loads when filled with material and in a free standing mode, and which preferably also provides for improved closure of the upper end of the bag.

According to the invention there is provided a lift bag for bulk material which is made of woven material which is closed at one end to form the bottom of the bag and which is provided with at least one lifting loop at its upper end below which openings are formed in opposed wall portions of the bag to permit filling of the bag and also subsequent engagement of a fork lift or hook with the loop to lift the bag and its contents; in which means is provided in the upper end portion of the bag which is automatically operative, or which can be operated, in order to contract the outer periphery of said upper end portion of the bag in order to form an at least partial closure of the upper end of the bag, and to taughten the woven material adjacent thereto, when the bag is left freestanding with its contents therein.

Any suitable means may be provided to effect the required contraction of the outer periphery of said upper end portion of the bag, when the latter is filled with material and left in a freestanding mode. Thus, in one form, this may be achieved by the formation of, or incorporation in the woven fabric of an elasticated portion. However, other means may be adopted, such as suitable pleating, or the use of a drawstring or the like.

One embodiment of lift bag according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a perspective illustration of the lift bag filled with bulk material. and suspended via its upper lifting loop by a fork lift; and, Figure 2 is a perspective view of the filled bag showing the form taken up by the bag when in a freestanding position.

Referring now to the drawing, a lift bag according to the invention is designated generally by reference 10, and is intended primarily for the storage and transportation of large volumes of bulk material, such as fertiliser. The bag has an outer liner 11 made of woven material which is closed at one end to form the bottom 12 of the bag and which is provided with one or more lifting loop 13 at its upper end, below which V-shaped openings 14 are formed in opposed wall portions of the bag to permit filling of the bag and also subsequent engagement by fork lift 15 (or a hook not shown) with the loop 13 to lift the bag and its contents.

Figure 1 shows the position taken up by the bag and its contents when suspended from fork lift 15, whereas Figure 2 shows a relaxed position taken up by the bag when unloaded on the ground during storage.

Means is provided in an upper end portion 16 of the bag which is automatically operative, or which can be operated, in order to contract the outer periphery of the upper end portion 16 in order to form an at least partial closure of the upper end of the bag, as can be seen from Figure 2, and whereby also this will effect taughtening of the woven material adjacent thereto, when the bag is left freestanding with its contents therein, as shown in Figure 2.

The means provided in the upper end portion 16 of the bag is not shown in Figures 1 and 2, but may take any suitable form to effect the required contraction of the outer periphery of the upper end portion 16 when the upper lifting load is no longer applied to the bag via loop 13, i.e. when the bag is freestanding as shown in Figure 2.

By way of example only, this means, when it is required to be automatically operative, may comprise the formation of, or incorporation in the woven fabric of an elasticated portion. whereby the warp length of the fabric in the portion 16 can automatically reduce when the upper load is removed.

However, other means may be adopted,-such as the formation of suitable pleating which can partly unfold when vertical load is applied to the lifting loop 13, but which can operate automatically to draw-in the outer periphery of the upper end portion 16 to take-up the position shown in Figure 2.

Alternatively, if the means provided is required to be capable of being operated manually, this means may comprise the incorporation of a suitable drawstring arranged in the region of the upper end portion 16.

Although not shown. usually a plastics film inner liner will be provided within the outer liner 11 of the bag 10, which will be filled with the bulk material contents of the bag.

Accordingly, the upper end of the bag can be made more rigid by reducing, within the lifting area. the total circumference of the warp tapes to a reduced area which, when relaxed and in a stored position, enables a proportion of the lifting area to form a closure or lid.

The benefits of the arrangement are, firstly, increased rigidity in the lifting area, and secondly a lid which contains the inner liner and therefore reduces the possibility of wind damage being done to the inner liner, and thirdly the risk of wind damage being done to the outer liner is also reduced.

Claims (10)

CLAIMS:

1. A lift bag for bulk material, which is made of material closed at one end to form the bottom of the bag and which is provided with at least one lifting loop at its upper end, below which loop openings are formed in opposed wall portions of the bag to permit filling of the bag and also subsequent engagement of a fork lift or hook with the loop to lift the bag and its contents; in which bag means is provided in the upper end portion of the bag which is automatically operative, or which can be operated, in order to contract the outer periphery of said upper end portion of the bag in order to form an at least partial closure of the upper end portion of the bag, and to tauten the bag material adjacent to said means, when the bag is left freestanding with its contents therein.

2. A lift bag according to claim 1, wherein the contraction means comprises an elasticated portion.

3. A lift bag according to claim 2, wherein said elasticated portion is incorporated in the material of the bag.

4. A lift bag according to any preceding claim, wherein the contraction means comprises pleating in the bag material.

5. A lift bag according to any preceding claim, wherein the contraction means comprises a drawstring or the like.

6. A lift bag according to any preceding claim, wherein said openings are substantially V-shaped.

7. A lift bag according to any preceding claim, and further comprising an inner liner to be filled with the bulk material.

8. A lift bag according to any preceding claim, wherein said bag material is woven.

9. A lift bag according to claim 8, wherein said bag material is polypropylene.

10. A lift bag substantially according to any one of the embodiment variations thereof hereinbefore described with reference to Figure 2 of the accompanying drawing.