GB1602726A

GB1602726A - Bulk material container

Info

Publication number: GB1602726A
Application number: GB1787677A
Authority: GB
Original assignee: Feltham & Son Ltd Walter H
Current assignee: Feltham & Son Ltd Walter H
Priority date: 1978-04-28
Filing date: 1978-04-28
Publication date: 1981-11-18

Description

(54) BULK MATERIAL CONTAINER (71) We, WALTER H. FELTHAM & SON LIMITED, a British Company of 6 Caxton Road, Wood Green, London N22 6TB, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to containers for bulk material, generally of finely divided form.

The use of large bags for transporting bulk quantities of powdered or granular material is known.

These bags, which frequently have carrying capacities of 0.5 tons upwards, the load depending, inter alia, on the bulk density of the material to be carried, are being used increasingly in place of small sacks having a capacity of about 50 kilos.

The bags may be of disposable form, in which case their contents are removable therefrom simply by suspending the bags and slitting the bottoms thereof, or of reusable type in which case some kind of opening means must be provided in the bottom thereof, for example a discharge chute with a tie cord or a discharge hole in which a self-sealing disc can be inserted. Such bags are loaded through an open mouth.

Containers for bulk material of the aforesaid type generally fall into one of three classes: a. Bags which have carrying loops attached thereto, the bags themselves taking the loading strain when suspended by the carrying loops.

Such containers are described in for exmple British patent specifications Nos. 1,431,581 and 1,431,582.

b. Bags formed with a metal lifting collar about the open mouth, the collars consisting of a heavy gauge tubular ring frame which enables the bag to be suspended for filling and emptying.

c. Bags comprising a webbing sling which provides loops by which the bag may be suspended for filling and which take up the major part of the strain imparted to the assembled sling and bag by material in the bag. The function of the bag is mainly to serve as a retaining means for the load therein.

This invention relates to bulk containers of the third aforesaid type, which containers have the advantage over the first two types of being capable of taking larger loads owing to the greater strength which webbing may possess over that of the bag-forming material and the absence of the need for sophisticated lifting machinery as is required with the second aforesaid type of bulk container.

According to the present invention, there is provided a container for bulk material which comprises a bag having a base, four sides upstanding from the base when the bag is full and a bag opening opposite the base, the bag being hemmed at the upstanding edge regions of two opposed sides to form slots, slots which are directly opposite each other being interconnected by means of slots of like width formed by hemming of marginal regions of the base of the bag, the through slots thereby formed housing webbing which extends out of mouths of the slots of said opposed sides above the bag opening where the webbing is formed into handles for engagement by lifting gear for the container.

Such containers have the particular advantage over containers of the third type as aforesaid hitherto produced of maintaining a basically straight-sided form when full thereby allowing more efficient packing of filled containers in for example the hold of a ship. Such forming of the container is made possible by the presence of hemming at the corner regions produced by stitching and acting as a reinforcement. With hitherto produced bags of the aforesaid third type, opposed margins of a tubular length of material have generally been welded together to laterally close the container.

Moreover, because the webbing is retained within slots, its position in relation to the base of the container when filled is guaranteed. In contrast, with hitherto produced containers of the aforesaid third type, the webbing which forms a sling passes around the outside of the container being fully exposed to view apart from when it passes through short retaining slots formed by welding of open ended patches of fabric to the outside of the container. With such bags, there is substantial risk that the webbing will slip in relation to the base of the container when fully loaded and possibly reduce support for the load in the container. The webbing may be threaded through the aforesaid slots in a number of different ways.For example, closed lengths of webbing may be located at opposite sides of the container, passing down one side wall hem, across the slot-forming hem in the base of the container and up the opposite upstanding hem before returning externally of the container to the first hem. This provides a two point lift bag since each of the pieces of webbing passing out of the container can be hooked onto a crane. A four point lift bag can be produced if the aforesaid arrangement is varied by dispensing with the final section of webbing as aforesaid passing outside the bag from one hemmed region to the opposite hemmed region and simply providing a length of webbing upstanding from each of the vertical slots and folded back on itself, the return portion being sewn to the main portion of the webbing.

The webbing loops thus formed may be sewn to the container itself thereby to avoid the risk of the webbing slipping out of the slots. The hemming of the upstanding edge regions of the opposed sides of the bag may be positioned internally or externally of the bag in either of which cases suitable arrangements of selvage of adjacent sides may be devised to allow edgewise sewing together of the sides of the bag. However, it has been found that greater strength is imparted to the bag if the hemming takes place externally of the bag.

Bags according to the present invention which can be loaded onto ships using conventional loading gear can be safely made of sufficient size to take 1 to 2 ton loads. The loads will generally be of particulate form, and include, for example, fertilisers, minerals, animal foodstuffs, feeds, clay, chemicals or detergents, metal powders, plastics granules, cement and even foodstuffs, provided that the containers are suitably lined.

The material of the container itself may be woven from a high tenacity synthetic fibre. for example. polypropylene. polyethylene terephthalate, rayon, nylon and mixtures thereof. It may also be possible to use a strong natural fibre. such as jute, since the major part of the loading is taken up by the webbing. Because of this factor, it has been found that a 5:1 safety ratio, i.e. an ability to take a load five times greater than that permitted by the strength of the bag forming material alone, can reliably be obtained when using lighter gauge bag forming material than hitherto used for this purpose. especially when external hemming as aforesaid is adopted.In general. it is possible to employ as bag forming material (12 to 18) x (10 to 15) per square inch woven polypropylene of from 1,000 to 2,000 denier. depending on loading arrangements. One suitable material for the bag is 15 x 12 per square inch woven polypropylene of 2,000 denier. this being a relatively cheap and readily available material possessing the required strength. A lighter material which will frequently meet requirements is 15 x 13 per square inch woven polypropylene of 1,150 denier. Polypropylene has a tensile strength of 5 gram per denier and a single 2,000 denier tape is thus capable of supporting 10,000 grams. With a weave of 15 tapes per inch, the tensile strength per inch then is thus 150 kilograms which is well above the preferred minimum figure of 83.3 kilograms.

The webbing employed to take the strain of a load carried in the container is preferably woven polyethylene terephthalate of the type used for vehicle seat belts.

For a better understanding of the invention, and to show how the same can be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, wherein: Figure 1 is a perspective view of one form of bag embodying this invention; Figures 2a and 2b show two stages in the formation of a seam whereby sides of the bag are joined together; Figure 3 is a perspective view on an enlarged scale of a corner of a bag of Figure 1; Figure 4 is a perspective view of an alternative form of bag embodying this invention; Figure 5 is a perspective view of a bag embodying this invention constructed in an alternative manner to that shown in Figure 1; Figure 6 is a perspective view on an enlarged scale of the bag of FigureS;; Figures 7a and 7b show schematically two ways in which a seam can be formed when joining the sides of the bag of Figure 5 together; Figure 8 shows a perspective view of a bagforming section during the provision of webbing therein; Figures 9a to 9d show stages in the formation of a spout-carrying base section of a bag embodying the invention; and Figure 10 is a section through a portion of the arrangement shown in Figure 9d showing the stitching involved in the connection of a spout to the bottom section.

Referring to Figure 1 of the drawings, the container is formed with a body 1 having a substantially square base 2, the preferred fabric for the body and base being polypropylene of 2,000 denier woven at 15 x 12 per square inch, that is with 15 warp tapes and 12 weft tapes to the inch.

The body is formed from a single length of fabric which provides the square base 2 and a pair of opposite side walls 3. The side walls are interconnected by panels 4 formed of the same polypropylene material and stitched at stitching positions shown generally at 5, 6 and 7 to marginal regions of the fabric length forming the side walls 3 and base 2 of the container. A hem is provided all around the upper margin of the container by folding over selvage at the respective side-forming portions to form a hem about one inch wide and applying stitching 8. Moreover, wide hems are provided at the long edge regions of the single length of fabric providing the side walls 3 and square base 2. These wide hems, shown at 9, provide a continous slot extending down the marginal region of one side 3 along the side of the square base 2 and up the opposite side wall marginal region. The slots accommodate lengths of webbing 10 extending the full lengths thereof and protruding from the ends 11 of the slot (see Figure 3), being bent back on themselves to form loops 12. The loops are closed by sewing of the overlying web material together.

The manner of joining together the panels 4 and the material forming the side walls 3 and square base 2 can be readily understood by reference to Figures 2a and 2b. Firstly a flap 13 of folded over side wall material is formed. The panel is then laid across the flap 13 and stitching 14 is formed through the single layer of panel 4 and the double layer of side wall material. The panel 4 is then bent back upon itself and further stitching 15 is provided passing through two layers of panel material and two layers of side wall material. When it is necessary for the panel 4 to be joined to the opposite side wall marginal region, an analogous procedure is adopted at the opposite side wall. The stitching 14 will generally be about 3/4 inch in from the fold in the material of the side wall 3.

Although the stitching 14 may form the outer margin of the hem 9, it is preferred, as shown in Figure 3, to provide additional stitching 9a defining the outer margin of the hem 9, the inner margin of the hem 9 being provided by stitching 9b generally positioned about 4 inches in from the fold in the side wall-forming material. The folding over of the panel 4 which is shown in Figure 3 reflects an alternative method of joining together the panel 4 and the side wall 3 involving provision of stitching through a single thickness of material of the panel 4.

Referring next to Figure 4, an alternative form of container embodying the invention is shown.

This container provides two point lifting, in contrast to the four point lifting shown in Figure 1. The walls of the container are formed in the same manner as in Figure 1. However, instead of the free ends of the webbing being formed into loops, they are here joined together to form a bridge section 16. By providing a continuous length of webbing, there is no risk that the webbing will be lost from the container. In contrast, with the container of Figure 1. there is the risk that this may happen and accordingly it is preferred that the webbing itself then be sewn into the slots formed by the hem 9.

Referring next to Figure 5, in which like reference numerals denote like parts to Figure 1, a variant of the bag shown in Figure 1 is shown in which the hem 9, instead of lying within the bag, lies on the exterior thereof, thereby providing two slots extending around the exterior of the bag. The webbing 10 lies in the slots in like manner to the webbing shown in Figure 1 and in all other respects, the basic construction of the bag is the same as that shown in Figure 1.

However, because of the greater load bearing capacity of the webbing when employed in this manner, it has been found to be possible to employ a lighter gauge polypropylene fabric for use in the construction of the bag. With such a construction, it is possible to employ a fabric for the body and base which is polypropylene of 1,150 denier at 15 x 13 per square inch, that is 15 warp tapes and 13 weft tapes to the inch. The manner in which the lengths of webbing 10 protrude from the ends 11 of the slots can be seen clearly by reference to Figure 6. Loops are closed by sewing of the overlying web material together (not shown).

The manner of joining together the panels 4 and the material forming the side walls 3 in the bag construction of Figure 5 can be readily understood by reference to Figures 7a and 7b in which analogous features to features shown in Figures 2a and 2b bear the same reference numerals as in Figures 2a and 2b with the addition of primes.

Thus referring to the constructional arrangement shown in Figure 7a, firstly a flap 13' folded under side wall forming material is formed. The panel 4 is then laid across the main part of the material of the side wall 3 and stitching 14' is formed through the single layer of panel 4 and one layer of side wall material. The panel 4 is then bent back upon itself and further stitching 15' is provided passing through the two layers of panel material and two layers of side wall material. This arrangement is in fact analogous to that achieved in Figure 2b.

The join achieved is a particularly strong one owing to the provision of stitching 15' through four layers of fabric. A less strong but more rapidly produced connection is illustrated in Figure 7b and is achieved by again folding the material of the side wall 3 to form a flap 13'. Only a marginal region of the panel 4 is then laid over the side wall 3 adjacent the fold therein and the panel is itself folded back on itself to provide a fold in line with the fold in the side wall forming material. When the panel forming material is in this latter disposition, two rows of stitching 17 and 18 each extending through two thicknesses of panel 4 and two thicknesses of side wall material 3 are formed. The arrangements shown in Figures 7a and 7b show additional details to those shown in Figures 2a and 2b concerning the construction of the hem 9.In particular, they show the provision of stitching at 9a and 9b about one inch and four inches respectively in from the fold in the side wall forming material defining the outer and inner margins respectivley of the slots formed by the hem 9.

In general, the formation of the hem 9 will be completed before joining together the sections of the bag. The webbing 10 will in fact be laid on the material being employed to form the base and side panels prior to completion of the hem 9 by provision of the stitching 9b as shown best by reference to Figure 8 in which like reference numerals denote like parts shown in the preceding drawings and which shows, in addition, stitching 19 whereby end loops are formed from the webbing 10.

The bags described hereinabove with reference to Figures 1 to 8 of the drawings are basically of the disposable type in that no special provision is made for emptying of particulate material therefrom. This will generally be achieved simply by slashing the underside of the bag. However. for reasons of economy, it is preferred that the bags be reusable and in this case, a spout depending from the base 2 is preferably provided, the spout generally being formed from the same material as the remainder of the bag and being closed either by means of a strap and a buckle or simply by folding over of the end of the spout and tying it with twine. The containers shown in Figures 1 and 5 are formed from three pieces of fabric, that is a long length forming the side panels 3 and base 2 and two smaller pieces forming the panels 4.If a spout is to be formed, this procedure is desirably modified by adopting the procedure of Figures 9a to 9d wherein the single piece of fabric for forming the side panels 3 and base 2 is replaced by three separate pieces of fabric given the reference numerals 3' for side wall-forming material and 2' for base-forming materal. A piece of fabric 21 having the same dimensions as the base panel 2' is laid over the base panel 2'. A circle 22 or other figure corresponding to the cross-section of the proposed spout is marked on the piece of material 21 and the pieces are stitched together at 23 adjacent and outside the circle 22 (Figure 9a).A hole 24 is then cut through the two layers of fabric2' and 21 and the upper of the two layers which is shown in Figures 9a and 9b to be the sheet 21 is drawn through the hole 24 and pulled out on the other side of the hole so as to lie flat underneath the panel 2' (Figure 9c). The side panels 3' are then sewn to the base panel 2', 21 and a tube 25 of the same fabric as the bag forming material is then sewn onto the base panel 2', 21 at aposition around the periphery of the hole 24. The assembled strip formed of side panels 3' and spout bearing panel 2', 21 is now ready for use in the assembly of the complete bag in place of the integral strip for forming side panels 3 and base 2 referred to hereinabove in connection with Figure 1 and 5. The bag is so assembled that the spout lies on the exterior of the base.

The manner of joining the spout to the base can be best observed by reference to Figure 10 in which the stitching 23 can be seen to be inverted as a result of the pulling through the holes 24 of the material 21. Owing to its being flexible, the spout 25 can readily be folded in the manner shown at its base region 26 to provide a triple thickness of spout material which is joined to the base by stitching 27 which additionally passes through four thicknesses of base-formingmaterial.

Although the containers referred to hereinabove in connection with the drawings are formed basically from three pieces of fabric, that is a piece forming the base and side walls and additional panels 4, it is possible for them to be formed from two pieces of fabric if it is not intended that a spout be formed. For this purpose, two lengths of fabric are laid in cruciform manner, the overlying portions are sewn together to provide a double thickness base and the remaining portions are brought up and sewn together where they adjoin, the marginal regions of at least one of the lengths of fabric having been formed with wide hemming as aforesaid in which webbing is disposed.

In use, the bag is filled through the opening defined by the side walls 3 and panels 4. The bag is lifted by engaging loops 12 or bridge sections 16. When suspended in this way, the major part of the strain caused by the loading in the bag is taken up by the webbing which has a much greater tensile strength than the sheet material from which the body of the container is formed.

If required, a cover provided with a filling spout may be provided for the container. Such a cover may be formed in the same manner as the central section made up of base panel 2', material 21 and spout 25 shown in Figure 9d. It will generally be attached to the remainder of the bag at the completion of construction thereof. The manner of sewing it to the bag in upper marginal regions thereof will not be critical since the cover will not be load bearing.

If required, an inner lining of impervious material, for example sheet polyethylene having a thickness of about 0.0035 inches can be used within the bag to prevent powder migrating through the woven fabric of the bag.

WHAT WE CLAIM IS:- 1. A container for bulk material which comprises a bag having a base, four sides upstanding from the base when the bag is full and a bag opening opposite the base, thebagbeinghemmed at the upstanding edge regions of two opposed sides to form slots, slots which are directly opposite each other being interconnected by means of slots of like width formed by hemming of marginal regions of the base of the bag, the through slots thereby formed housing webbing which extends out of mouths of the slots of said opposed sides above the bag opening where the webbing is formed into handles for engagement by lifting gear for the container.

2. A container is claimed in claim 1 wherein all said slots lie within the bag.

3. A container as claimed in claim 1, wherein the bag is hemmed in such manner that all said slots lie outside the bag.

4. A container as claimed in any one of the preceding claims, wherein the end portions of lengths of webbing protrude from mouths of the slots at upper margins of the bag and each end portion is bent over and sewn to another part of the length of webbing protruding from the same slot to form a loop.

5. A container as claimed in any one of claims 1 to 3, wherein lengths of webbing protruding from some of said slots are sewn to lengths of webbing protruding from other slots to form lifting handles.

6. A container as claimed in claimS, wherein the protruding lengths of the same piece of webbing are joined together to form said handles .

7. A container as claimed in any one of the preceding claims, wherein the bag is formed of woven polypropylene, polyethylene terephthalate, rayon or nylon fibres or from a mixture of said fibres.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. reasons of economy, it is preferred that the bags be reusable and in this case, a spout depending from the base 2 is preferably provided, the spout generally being formed from the same material as the remainder of the bag and being closed either by means of a strap and a buckle or simply by folding over of the end of the spout and tying it with twine. The containers shown in Figures 1 and 5 are formed from three pieces of fabric, that is a long length forming the side panels 3 and base 2 and two smaller pieces forming the panels 4.If a spout is to be formed, this procedure is desirably modified by adopting the procedure of Figures 9a to 9d wherein the single piece of fabric for forming the side panels 3 and base 2 is replaced by three separate pieces of fabric given the reference numerals 3' for side wall-forming material and 2' for base-forming materal. A piece of fabric 21 having the same dimensions as the base panel 2' is laid over the base panel 2'. A circle 22 or other figure corresponding to the cross-section of the proposed spout is marked on the piece of material 21 and the pieces are stitched together at 23 adjacent and outside the circle 22 (Figure 9a).A hole 24 is then cut through the two layers of fabric2' and 21 and the upper of the two layers which is shown in Figures 9a and 9b to be the sheet 21 is drawn through the hole 24 and pulled out on the other side of the hole so as to lie flat underneath the panel 2' (Figure 9c). The side panels 3' are then sewn to the base panel 2', 21 and a tube 25 of the same fabric as the bag forming material is then sewn onto the base panel 2', 21 at aposition around the periphery of the hole 24. The assembled strip formed of side panels 3' and spout bearing panel 2', 21 is now ready for use in the assembly of the complete bag in place of the integral strip for forming side panels 3 and base 2 referred to hereinabove in connection with Figure 1 and 5. The bag is so assembled that the spout lies on the exterior of the base. The manner of joining the spout to the base can be best observed by reference to Figure 10 in which the stitching 23 can be seen to be inverted as a result of the pulling through the holes 24 of the material 21. Owing to its being flexible, the spout 25 can readily be folded in the manner shown at its base region 26 to provide a triple thickness of spout material which is joined to the base by stitching 27 which additionally passes through four thicknesses of base-formingmaterial. Although the containers referred to hereinabove in connection with the drawings are formed basically from three pieces of fabric, that is a piece forming the base and side walls and additional panels 4, it is possible for them to be formed from two pieces of fabric if it is not intended that a spout be formed. For this purpose, two lengths of fabric are laid in cruciform manner, the overlying portions are sewn together to provide a double thickness base and the remaining portions are brought up and sewn together where they adjoin, the marginal regions of at least one of the lengths of fabric having been formed with wide hemming as aforesaid in which webbing is disposed. In use, the bag is filled through the opening defined by the side walls 3 and panels 4. The bag is lifted by engaging loops 12 or bridge sections 16. When suspended in this way, the major part of the strain caused by the loading in the bag is taken up by the webbing which has a much greater tensile strength than the sheet material from which the body of the container is formed. If required, a cover provided with a filling spout may be provided for the container. Such a cover may be formed in the same manner as the central section made up of base panel 2', material 21 and spout 25 shown in Figure 9d. It will generally be attached to the remainder of the bag at the completion of construction thereof. The manner of sewing it to the bag in upper marginal regions thereof will not be critical since the cover will not be load bearing. If required, an inner lining of impervious material, for example sheet polyethylene having a thickness of about 0.0035 inches can be used within the bag to prevent powder migrating through the woven fabric of the bag. WHAT WE CLAIM IS:-

1. A container for bulk material which comprises a bag having a base, four sides upstanding from the base when the bag is full and a bag opening opposite the base, thebagbeinghemmed at the upstanding edge regions of two opposed sides to form slots, slots which are directly opposite each other being interconnected by means of slots of like width formed by hemming of marginal regions of the base of the bag, the through slots thereby formed housing webbing which extends out of mouths of the slots of said opposed sides above the bag opening where the webbing is formed into handles for engagement by lifting gear for the container.

2. A container is claimed in claim 1 wherein all said slots lie within the bag.

8. A container as claimed in claim 7, wherein

the bag is formed of (12 to 18) x (10 to 15) per square inch woven polypropylene of from 1,000 to 2,000 denier.

9. A container as claimed in claim 8, wherein the bag is formed from 15 x 12 per square inch woven polypropylene of 2,000 denier.

10. A container as claimed in claim 8, wherein the bag is formed from 15 x 13 per square inch woven polypropylene of 1,150 denier.

11. A container as claimed in any one of the preceding claims which has a 5:1 safety ratio as hereinbefore defined.

12. A container as claimed in any one of the preceding claims, wherein the webbing is formed of woven polyethylene terephthalate fibre.

13. A container as claimed in claim 2 or any one of claims 4 to 12 when appended to claim 2, wherein a said opposed side is connected to an adjoining side in the manner substantially as described herein with reference to Figures 2a and 2b of the accompanying drawings.

14. A container as claimed in claim 3 or any one of claims 4 to 12 when appended to claim 3, wherein a said opposed side is connected to an adjoining side in amannersubstantiallyashereinbefore described with reference to Figure 7a or 7b of the accompanying drawings.

15. A container as claimed in any one of the preceding claims, whose base is formed with an emptying spout depending therefrom.

16. A container as claimed in claim 15, wherein the spout is joined to the base in a manner substantially as hereinbefore described with reference to Figures 9a to 9d and 10 of the accompanying drawings.

17. A container as claimed in any one of Claims 1 to 12, wherein said two opposed sides and base are formed of a continous length of material.

18. A container of bulk material, substantially as hereinbefore described with reference to, and as shown in, Figure 1 or 4 of the accompanying drawings in conjunction with Figures 2a and 2b or Figure 3 of the accompanying drawings.

19. A container for bulk material, substantially as hereinbefore described with reference to, and as shown in, Figure 5 of the accompanying drawings optionally in conjunction with Figures 6 and 7a or Figure 7b of the accompanying drawings.